Toric ICL: Astigmatism Correction, Suitability, Procedure, Risks and Recovery

Author: Dr Val Phua
Estimated reading time: 22 minutes

A Toric Implantable Collamer Lens, or Toric ICL, is an intraocular lens designed to correct both myopia and regular astigmatism without removing the natural crystalline lens.

It is sometimes described as a toric “implantable contact lens”. The formal name is Toric Implantable Collamer Lens because the lens is made from Collamer and is surgically positioned inside the eye.

During Toric ICL surgery:

A small incision is created at the edge of the cornea.
The folded Toric ICL is inserted into the eye.
It unfolds behind the iris and in front of the natural lens.
The lens is rotated to a precisely calculated axis.
Its four footplates are positioned behind the iris.
The incision usually seals without stitches.

A standard spherical ICL corrects myopia.

A Toric ICL corrects:

Myopia
Regular astigmatism

The toric component must remain accurately aligned with the intended axis. A correctly powered lens that rotates significantly may leave residual astigmatism and reduce unaided vision.

Modern Toric ICL studies generally report:

High refractive predictability
Good unaided distance vision
Stable astigmatic correction
Favourable rotational stability
High patient satisfaction

However, Toric ICL implantation is intraocular surgery.

Possible complications include:

Rotation away from the intended axis
Residual astigmatism
Inappropriate vault
Raised eye pressure
Cataract formation
Endothelial cell loss
Inflammation
Infection
Halos or glare
The need for lens realignment or exchange

Successful treatment therefore depends on more than choosing the correct lens power. It requires accurate refraction, careful anatomical measurements, appropriate sizing, precise axis marking and long-term monitoring.

The Quick Answer

What Is a Toric ICL?

A Toric ICL is a thin, foldable phakic intraocular lens.

“Phakic” means that the natural crystalline lens remains inside the eye.

The Toric ICL is positioned:

Behind the iris
In front of the natural lens
Within the posterior chamber of the eye

The lens contains:

A spherical component to correct myopia
A cylindrical component to correct astigmatism

What Is the Difference Between a Standard ICL and a Toric ICL?

A standard spherical ICL corrects myopia but does not fully correct clinically significant astigmatism.

A Toric ICL corrects both:

The spherical myopic prescription
The cylindrical astigmatic prescription

The Toric ICL must be implanted at a specific axis.

Is Toric ICL Surgery Painful?

Most patients experience little or no pain during surgery.

Anaesthetic eye drops are commonly used.

The patient may notice:

Bright lights
Gentle pressure
Cool fluid
Blurred movement
Mild awareness of the eye being touched

Sharp pain is not expected and should be reported immediately.

How Long Does the Procedure Take?

The surgical portion commonly takes approximately 10 to 30 minutes per eye in an uncomplicated case.

Additional time is needed for:

Registration
Preoperative markings
Pupil dilation
Preparation
Anaesthesia
Eye-pressure monitoring
Postoperative examination

How Quickly Does Vision Recover?

Many patients notice a major improvement within the first day.

Vision may continue improving over:

Several days
Several weeks
Occasionally several months

Temporary blur may result from:

Pupil dilation
Mild corneal swelling
Inflammation
Dry eye
Residual refractive error
Toric-axis settling
Neuroadaptation

Is the Toric ICL Permanent?

The lens is designed to remain inside the eye long term.

It does not require routine replacement after a fixed number of years.

The lens may nevertheless need to be repositioned, exchanged or removed if:

It rotates significantly
The vault is unsuitable
Cataract develops
Eye pressure becomes problematic
The prescription changes significantly
Another intraocular operation is required

Is Toric ICL Surgery Reversible?

The lens can usually be surgically removed.

It is more accurate to describe the procedure as removable rather than completely reversible.

The eye has still undergone intraocular surgery, and removal does not guarantee that every measurement or visual characteristic returns precisely to its preoperative state.

Understanding Astigmatism

What Is Astigmatism?

Astigmatism occurs when the eye has different focusing power in different meridians.

Instead of focusing light into one sharp point, the eye creates two principal focal lines or a more elongated blur.

Regular astigmatism may be caused by:

Corneal curvature
The natural crystalline lens
A combination of corneal and internal optical factors

Possible symptoms include:

Blurred distance vision
Blurred near vision
Ghosting
Shadowed letters
Eye strain
Headaches
Glare
Starbursts
Difficulty driving at night

What Is Regular Astigmatism?

Regular astigmatism has principal meridians that are approximately perpendicular to each other.

It can usually be represented by:

Cylinder power
Cylinder axis

Regular astigmatism may be corrected with:

Spectacles
Toric contact lenses
Corneal laser treatment
A Toric ICL
A toric intraocular lens during cataract surgery

What Is Irregular Astigmatism?

Irregular astigmatism occurs when the corneal surface does not form two regular perpendicular meridians.

Possible causes include:

Keratoconus
Corneal scarring
Previous infection
Eye trauma
Previous corneal surgery
Corneal ectasia
Contact-lens warpage

A Toric ICL may reduce the regular refractive component but does not reshape or regularise an abnormal cornea.

Patients with substantial irregular astigmatism may still require:

Rigid gas-permeable lenses
Scleral lenses
Corneal cross-linking
Topography-guided treatment
Other corneal procedures

How Does a Toric ICL Correct Astigmatism?

The lens has different optical powers in different meridians.

Its cylindrical correction must align with the eye’s astigmatic axis.

The planned lens incorporates:

Spherical power
Cylindrical power
A defined toric orientation

The manufacturer’s calculation system determines the intended implantation axis using information such as:

Manifest refraction
Corneal astigmatism
Surgically induced astigmatism
Incision location
Vertex-distance conversion
Lens model and power availability

Why Does the Axis Matter?

A toric lens must remain close to its intended axis to provide the planned correction.

Rotation reduces the effective cylindrical correction.

As a useful approximation:

1 degree of rotation loses about 3.3% of the cylindrical effect.
5 degrees loses about 17%.
10 degrees loses about one-third.
15 degrees loses about half.
30 degrees effectively neutralises the intended cylinder correction.

Rotation beyond 30 degrees may introduce astigmatism in an unintended direction.

The clinical effect also depends on the cylinder power.

A small rotation may be more noticeable when the Toric ICL contains a high cylindrical correction.

What Is the Toric ICL Axis?

The axis describes the orientation of the cylindrical correction.

It should not be confused with:

The incision meridian
The lens footplate direction
The corneal steep meridian
The spectacle-cylinder axis without conversion
The axis printed on a glasses prescription

The surgeon follows the planned implantation orientation generated for the specific lens.

Does the Spectacle Prescription Directly Determine the ICL Power?

Not by itself.

Spectacle refraction is measured some distance in front of the eye.

The ICL is positioned inside the eye.

The calculation must account for:

Vertex distance
Spherical power
Cylindrical power
Axis
Anterior-chamber depth
Lens position
Available lens powers
Expected surgically induced astigmatism

The final Toric ICL power should be calculated using the approved manufacturer planning system and verified by the surgeon.

Corneal Versus Refractive Astigmatism

The spectacle-cylinder measurement reflects the total optical astigmatism of the eye.

Corneal topography measures primarily the anterior corneal surface.

The two measurements may differ because of:

Posterior corneal astigmatism
Natural-lens astigmatism
Tear-film instability
Measurement variability
Contact-lens warpage
Accommodation
Irregular corneal shape

The surgeon should determine whether the astigmatism is:

Consistent
Regular
Stable
Appropriate for toric correction

Who May Be Suitable for a Toric ICL?

A suitable patient generally has:

Myopia
Clinically significant regular astigmatism
A stable spectacle prescription
Adequate anterior-chamber depth
Adequate endothelial cell density
Suitable internal eye dimensions
A clear natural crystalline lens
No uncontrolled glaucoma
No active eye inflammation
Realistic expectations
The ability to attend long-term reviews

Toric ICL may be especially useful when:

Myopia is high
Corneal laser treatment would remove excessive tissue
The cornea is relatively thin but structurally normal
Dry-eye risk is significant
The patient wishes to preserve corneal tissue
Optical quality is a major priority
Astigmatism is too large to leave untreated

How Much Astigmatism Is Needed?

The threshold depends on:

Available Toric ICL powers
The patient’s symptoms
Corneal and refractive measurements
Expected residual cylinder
Alternative treatment options
Local regulatory approval

A very small amount of astigmatism may not justify a toric lens if the expected clinical benefit is minimal.

Significant astigmatism should not be ignored because residual cylinder may reduce:

Unaided visual acuity
Contrast
Night vision
Satisfaction
Quality of vision

Can Toric ICL Treat Low Myopia?

Yes, in selected patients.

A Toric ICL may be considered in lower myopia when:

Corneal laser surgery is unsuitable
Astigmatism is significant
The ocular surface is poor
The patient wishes to avoid corneal tissue removal
The eye has suitable internal anatomy
The patient accepts intraocular surgical risks and long-term monitoring

The balance of benefits and risks differs from high myopia because patients with low myopia may also achieve excellent vision with:

Spectacles
Toric contact lenses
LASIK
Femto-LASIK
PRK
TransPRK
SMILE

Is Toric ICL Especially Useful for High Myopic Astigmatism?

Yes.

High myopia combined with astigmatism may require substantial corneal tissue removal if treated with laser surgery.

Toric ICL offers:

Correction of a large spherical prescription
Correction of regular astigmatism
No corneal stromal ablation
Preservation of corneal shape
Potentially favourable optical quality
A large effective optical zone

Published studies of Toric ICL implantation generally demonstrate strong refractive and visual outcomes in moderate-to-high myopic astigmatism.

How Stable Must the Prescription Be?

The prescription should generally be stable for at least approximately one year.

The surgeon should compare previous:

Spectacle prescriptions
Contact-lens prescriptions
Manifest refractions
Cycloplegic refractions
Corneal measurements

Ongoing refractive change increases the risk of residual myopia or astigmatism after surgery.

Is There a Minimum Age?

Toric ICL surgery is generally performed in adults with stable refraction.

The exact age range depends on:

Lens model
Local regulatory approval
Prescription stability
Ocular anatomy
Surgeon assessment

Reaching the minimum permitted age does not automatically establish suitability.

Is There a Maximum Age?

There is no single biological cut-off for every patient.

Increasing age raises additional issues, including:

Presbyopia
Early cataract
Natural-lens growth
Declining endothelial cell density
Glaucoma risk
Future cataract surgery

A patient with early cataract may be better served by cataract surgery with a toric intraocular lens rather than placing a Toric ICL in front of a lens that may soon require removal.

Who May Not Be Suitable?

Toric ICL may be inappropriate or require particular caution in the presence of:

A shallow anterior chamber
Low endothelial cell density
Visually significant cataract
Uncontrolled glaucoma
Narrow drainage angles
Active uveitis
Active eye infection
Significant iris abnormalities
Zonular weakness
Unstable refraction
Severe irregular astigmatism
Uncontrolled diabetes
Pregnancy or breastfeeding
Unrealistic expectations

Pregnancy and Breastfeeding

Elective Toric ICL surgery is generally postponed during pregnancy and breastfeeding.

Possible concerns include:

Refractive fluctuation
Changes in corneal curvature
Tear-film instability
Medication exposure
Hormonal influences on measurement stability

The prescription should be rechecked after the eyes have stabilised.

Diabetes

Well-controlled diabetes does not automatically exclude every patient.

The assessment should consider:

Glucose stability
HbA1c
Diabetic retinopathy
Lens clarity
Corneal endothelial health
Wound healing
Infection risk
Refractive stability

Poorly controlled diabetes may cause fluctuating refraction and less predictable outcomes.

Keratoconus

Toric ICL does not treat keratoconus.

It may be considered in selected stable keratoconic eyes when:

Progression has been controlled
Cross-linking has been performed when indicated
Refraction is stable
The astigmatism has a correctable regular component
The patient achieves useful corrected vision with spectacles
Internal eye anatomy is suitable

A Toric ICL cannot fully correct severe irregular astigmatism.

The Preoperative Assessment

Toric ICL planning requires both refractive and anatomical assessment.

The surgeon must determine:

The appropriate spherical power
The appropriate cylindrical power
The intended axis
The lens size
The expected vault
The likelihood of rotational stability
The health of the natural lens and corneal endothelium

Medical and Eye History

Important information includes:

Previous eye surgery
Eye trauma
Glaucoma
Uveitis
Cataract
Diabetes
Autoimmune disease
Medication
Pregnancy plans
Contact-lens use
Retinal tears or detachment
Previous corneal laser surgery
Keratoconus or cross-linking

Visual-Acuity Testing

Both unaided and corrected vision are measured.

Corrected vision establishes the eye’s visual potential.

Toric ICL cannot reverse poor vision caused by:

Amblyopia
Retinal disease
Optic-nerve damage
Macular scarring
Advanced glaucoma
Severe irregular astigmatism

Manifest Refraction

Manifest refraction determines the subjective spectacle prescription.

The measurement should be:

Repeatable
Stable
Consistent with previous prescriptions
Consistent with the patient’s visual experience

Small errors in cylinder power or axis can affect the final toric result.

Cycloplegic Refraction

Cycloplegic drops temporarily relax accommodation.

This may be helpful in:

Younger adults
Inconsistent refraction
Accommodative spasm
Large differences between subjective and objective measurements

Corneal Topography

Topography assesses anterior corneal curvature.

It helps determine whether astigmatism is:

Regular
Symmetrical
Stable
Associated with keratoconus
Caused partly by contact-lens warpage

Corneal Tomography

Tomography provides three-dimensional assessment of:

Anterior corneal curvature
Posterior corneal curvature
Corneal thickness
Corneal elevation
Astigmatic pattern
Ectasia-risk indices

Although ICL does not remove corneal tissue, tomography remains important because a Toric ICL should not be expected to correct an unstable or highly irregular cornea.

Contact Lenses Before Measurements

Contact lenses can alter:

Corneal curvature
Astigmatism magnitude
Astigmatism axis
Tear-film quality
Refraction

They should be discontinued before definitive measurements.

The required interval depends on:

Soft or rigid lens type
Duration of wear
Toric-lens stability
Orthokeratology
Corneal warpage
Repeat measurement stability

Anterior-Chamber Depth

Anterior-chamber depth is the distance between the corneal endothelium and the natural lens.

Adequate space is required to protect:

The corneal endothelium
The drainage angle
The natural lens

The minimum acceptable depth depends on:

Lens model
Measurement method
Local regulatory requirements
Endothelial cell count
Surgeon judgement

White-to-White Measurement

White-to-white is the visible horizontal corneal diameter.

It has traditionally been used with anterior-chamber depth to recommend ICL size.

However, the Toric ICL rests behind the iris rather than at the visible corneal edge.

White-to-white is therefore an indirect estimate of the space supporting the lens.

Anterior-Segment OCT

Anterior-segment OCT may assess:

Anterior-chamber width
Angle-to-angle distance
Crystalline-lens rise
Anterior-chamber depth
Angle configuration
Postoperative vault
ICL position
Toric orientation

Ultrasound Biomicroscopy

Ultrasound biomicroscopy can image structures behind the iris.

It may assess:

Sulcus-to-sulcus distance
Ciliary-body anatomy
Ciliary sulcus shape
ICL footplate position
Posterior-chamber relationships
Causes of unusual vault or rotation

Endothelial Cell Count

The corneal endothelial cells keep the cornea clear by pumping fluid out of it.

These cells do not regenerate substantially after loss.

The preoperative examination assesses:

Cell density
Cell-size variation
Cell shape
Age-related reserve

Long-term endothelial monitoring remains important after any ICL implantation.

Pupil Measurement

Pupil size may influence:

Halos
Glare
Night vision
Awareness of the central port
Optical edge effects

A large pupil does not automatically exclude surgery but should be included in counselling.

Eye-Pressure and Angle Assessment

Eye pressure is measured before surgery.

The drainage angles are assessed because an ICL may narrow them, particularly if the vault is high.

Retinal Examination

Patients seeking Toric ICL commonly have moderate or high myopia.

High myopia increases the lifetime risk of:

Retinal tears
Retinal detachment
Myopic macular degeneration
Macular schisis
Peripheral retinal degeneration

Correcting the refractive error does not remove these risks.

Planning the Toric Power

The calculation considers:

Manifest spherical power
Manifest cylindrical power
Cylinder axis
Vertex-distance conversion
Incision location
Expected surgically induced astigmatism
Available Toric ICL powers
Intended lens position

The final calculation should use the manufacturer-approved planning software.

Why Must the Incision Be Included?

A corneal incision can create a small amount of astigmatic change.

This is called surgically induced astigmatism.

The magnitude is generally small with a modern small incision but may still matter when planning precise toric correction.

The calculation may account for:

Incision width
Incision location
Surgeon-specific effect
Corneal biomechanics

What Is Cyclotorsion?

Cyclotorsion is rotation of the eye around its visual axis.

The eye may rotate when a patient moves from:

Sitting upright
To lying flat under the operating microscope

If the eye rotates but the planned axis is not adjusted, the Toric ICL may be aligned incorrectly.

How Is the Axis Marked?

Possible methods include:

Manual limbal marking while the patient is sitting upright
A reference mark at the horizontal meridian
A toric axis marker
Digital image-guided registration
Intraoperative navigation systems

Manual marking should generally be performed before:

The patient lies down
The pupil is widely dilated
Surface landmarks become distorted

Is Digital Marking More Accurate?

Digital systems may reduce:

Ink-mark fading
Smudging
Marker misplacement
Cyclotorsion error
Subjective axis estimation

However, they depend on:

Clear preoperative imaging
Reliable registration
Stable ocular-surface landmarks
Correct calibration
Surgeon verification

Technology does not replace careful confirmation of the correct eye, lens and axis.

ICL Sizing

Toric ICLs are available in several overall lengths.

The selected size influences:

Vault
Lens stability
Contact with the ciliary sulcus
Likelihood of movement or rotation
Anterior-chamber crowding

Sizing is therefore important for both anatomical safety and toric stability.

What Is Vault?

Vault is the distance between:

The posterior surface of the Toric ICL
The anterior surface of the natural crystalline lens

Vault is commonly measured using anterior-segment OCT.

Why Does Vault Matter?

A suitable vault helps protect:

The natural lens
The drainage angle
The iris
The corneal endothelium

It also influences how the ICL fits within the eye.

A lens with poor anatomical fit may be more likely to:

Rotate
Decentre
Produce an unsuitable vault
Contact surrounding structures

What Is an Ideal Vault?

There is no single ideal value for every patient.

A commonly used clinical target is approximately 250 to 750 micrometres.

The result must be interpreted with:

Patient age
Natural-lens position
Angle width
Eye pressure
Endothelial cell density
Toric stability
Changes over time

Does Vault Affect Rotation?

Vault and rotation may be related because both are influenced by:

Lens size
Ciliary sulcus anatomy
Footplate position
Lens orientation
Internal ocular dimensions

However, they are not interchangeable.

A lens can have:

An acceptable vault but rotate
A high vault but remain stable
A low vault without significant rotation

Rotational stability must be assessed directly.

Does Vault Change Over Time?

Yes.

Vault may vary with:

Pupil size
Lighting
Accommodation
Natural-lens growth
ICL orientation
Body position
Measurement method
Age

Long-term follow-up studies suggest that vault often decreases gradually as the natural lens thickens and moves forwards with age.

Low Vault

A low vault places the Toric ICL close to the natural lens.

Possible concerns include:

Contact with the natural lens
Anterior subcapsular lens opacity
Cataract
Reduced margin for future lens growth

A low numerical vault does not always require immediate surgery.

The decision depends on:

Actual lens contact
Patient age
Lens clarity
Eye pressure
Stability over time

High Vault

A high vault pushes the iris forwards.

Possible concerns include:

Narrow drainage angles
Raised eye pressure
Pigment dispersion
Iris contact
Increased proximity to the corneal endothelium

Can a Toric ICL Be Rotated to Change the Vault?

Changing the orientation of a spherical ICL may alter vault in selected eyes because internal dimensions vary between meridians.

A Toric ICL is different.

Its cylinder must remain aligned with the planned optical axis.

Rotating it solely to alter vault may create significant residual astigmatism.

If the vault is unsuitable, management may require:

Observation
A specially recalculated orientation
Lens exchange
A different lens size
Removal

How Is Toric ICL Surgery Performed?

Step 1: Confirming the Plan

Before surgery, the team confirms:

Patient identity
Correct eye
Lens model
Lens size
Spherical power
Cylindrical power
Planned implantation axis
Allergies
Consent

Step 2: Axis Marking

Reference marks may be placed while the patient is sitting upright.

This helps account for cyclotorsion when the patient later lies beneath the microscope.

Step 3: Pupil Dilation

Dilating drops enlarge the pupil.

This allows the lens to pass behind the iris.

Step 4: Anaesthesia

Anaesthetic eye drops numb the eye.

Mild sedation may be given.

Step 5: Sterile Preparation

The eyelids and surrounding skin are cleaned.

A sterile drape is placed around the eye.

An eyelid holder keeps the eye open.

Step 6: Creating the Corneal Incision

A small incision is made near the corneal edge.

One or more side-port incisions may also be created.

The incision location should match the toric calculation whenever surgically induced astigmatism has been incorporated.

Step 7: Maintaining the Anterior Chamber

The surgeon may use:

Ophthalmic viscosurgical material
Balanced salt solution
Another chamber-maintenance technique

The purpose is to preserve space and protect the internal eye structures.

Step 8: Inserting the Lens

The folded Toric ICL is loaded into an injector.

It is delivered through the small incision.

Step 9: Allowing the Lens to Unfold

The lens unfolds inside the anterior chamber.

The surgeon confirms that it is not:

Inverted
Twisted
Damaged
Trapped in the incision

Step 10: Positioning the Footplates

The four footplates are gently placed behind the iris.

The ICL rests in the posterior chamber in front of the natural lens.

Step 11: Rotating to the Planned Axis

The surgeon aligns the toric reference marks with the intended axis.

This may be guided by:

Preoperative ink marks
A toric marker
Digital image guidance
Intraoperative registration

Step 12: Removing Viscoelastic

When a viscosurgical material has been used, it is removed thoroughly.

Retained viscoelastic can cause a marked early rise in eye pressure.

Step 13: Final Checks

The surgeon assesses:

Lens centration
Toric axis
Pupil shape
Corneal wound
Anterior-chamber depth
Immediate vault appearance
Chamber stability

The incision usually seals without stitches.

Can Both Eyes Be Treated Together?

Practice varies.

Possible approaches include:

One eye at a time
Separate surgical dates
Bilateral same-day surgery under strict protocols

Separating the eyes allows the surgeon to assess:

First-eye vault
First-eye rotation
First-eye refractive result
Pressure response

The second-eye plan may occasionally be adjusted based on the first-eye findings.

What Happens Immediately Afterwards?

Temporary symptoms may include:

Blurred vision
Light sensitivity
Mild aching
Grittiness
Watering
Halos
A dilated pupil
Redness

Vision may improve quickly but can fluctuate.

The First Postoperative Examination

The review commonly assesses:

Unaided vision
Refraction when required
Toric axis
Vault
Eye pressure
Corneal clarity
Inflammation
Wound integrity

Eye Drops After Surgery

Medication may include:

Antibiotic drops
Steroid drops
Non-steroidal anti-inflammatory drops
Eye-pressure-lowering medication
Lubricating drops

Patients should:

Wash their hands
Avoid touching the bottle tip to the eye
Space different drops apart
Use the prescribed taper
Avoid stopping steroid medication without advice

The First Week

Vision generally continues to sharpen.

Temporary symptoms may include:

Halos
Glare
Mild dryness
Fluctuating focus
Light sensitivity

The Toric ICL axis may be rechecked if unaided vision is less clear than expected.

The First Month

The refractive result and lens position become more stable.

The surgeon may reassess:

Residual cylinder
Axis alignment
Vault
Eye pressure
Natural-lens clarity

Long-Term Follow-Up

Long-term examinations may include:

Unaided and corrected vision
Refraction
Toric axis
Eye pressure
Drainage-angle assessment
Vault measurement
Natural-lens examination
Endothelial cell count
Retinal examination

Expected Visual Results

Modern Toric ICL implantation generally provides strong refractive outcomes in appropriately selected eyes.

Published studies report:

High rates of useful unaided distance vision
Significant reduction in refractive cylinder
Good rotational stability
Stable corrected vision
High patient satisfaction

The result depends on:

Accuracy of refraction
Appropriate cylindrical power
Accurate axis planning
Lens size
Rotational stability
Vault
Retinal and optic-nerve health
Healing

How Much Residual Astigmatism May Remain?

A small amount may remain because of:

Available lens-power increments
Measurement variation
Posterior corneal astigmatism
Surgically induced astigmatism
Minor rotation
Natural refractive change
Irregular corneal optics

The presence of a small residual cylinder does not necessarily mean that the lens has rotated.

Rotational Stability

Modern Toric ICLs generally demonstrate favourable rotational stability.

Most lenses remain sufficiently close to the intended axis to preserve useful cylinder correction.

However, clinically significant rotation can occur.

Possible contributors include:

Lens size
Internal eye anatomy
Ciliary sulcus shape
Footplate position
Vault
Implantation orientation
Surgical manipulation
Individual variation

When Does Rotation Occur?

Rotation may be detected:

During surgery
During the first postoperative day
During the first few weeks
Less commonly later

Some early movement may occur as the lens settles.

Late rotation is less common but remains possible.

How Is Rotation Measured?

The surgeon may use:

Slit-lamp examination
Dilated inspection of lens marks
Retroillumination photography
Anterior-segment OCT
Digital image analysis
Comparison with the planned axis

The axis should be interpreted together with the residual refraction.

Symptoms of Toric ICL Rotation

Possible symptoms include:

Blurred distance vision
Ghosting
Shadowed images
Headlight streaking
Reduced night vision
Unequal vision between the eyes
Vision that was initially clear and became worse

Small rotation may cause no noticeable symptoms.

How Much Rotation Requires Treatment?

There is no universal numerical threshold.

The decision depends on:

Degree of rotation
Toric power
Residual astigmatism
Unaided vision
Patient symptoms
Stability over repeated visits
Likelihood of recurrent rotation

A 5-degree rotation may matter in a high-cylinder lens but cause little difficulty in a low-cylinder lens.

What Happens if the Toric ICL Rotates?

Management may include:

Observation
Repeat refraction
Confirming the true axis
Treating dry eye
Spectacle correction
Surgical realignment
Lens exchange
Corneal laser enhancement in selected cases

Surgical Realignment

The surgeon re-enters the eye through a small incision and rotates the ICL to the intended axis.

Realignment may be considered when:

Rotation is clinically significant
Residual cylinder affects vision
The lens is otherwise appropriately sized
Recurrent rotation is considered unlikely

Recurrent Rotation

If the lens rotates again after realignment, possible causes include:

Inappropriate lens size
Poor anatomical fit
Unusual sulcus anatomy
Unstable footplate position
Inappropriate implantation orientation

Lens exchange may be more appropriate than repeated realignment.

Lens Exchange

The Toric ICL may be exchanged for:

A different size
A different toric power
A differently planned orientation
A spherical ICL with separate astigmatism treatment
No implant, when removal is preferred

Exchange is another intraocular operation and carries additional risk.

Residual Astigmatism Without Rotation

Residual cylinder may occur even when the Toric ICL is correctly aligned.

Possible explanations include:

Inaccurate preoperative refraction
Contact-lens-induced corneal warpage
Posterior corneal astigmatism
Surgically induced astigmatism
Available lens-power limitations
Irregular astigmatism
Natural-lens changes

Treatment should address the cause rather than automatically rotating the lens.

Laser Enhancement After Toric ICL

A small residual refractive error may sometimes be treated with:

LASIK
Femto-LASIK
PRK
TransPRK

This may be considered when:

The Toric ICL is well positioned
The axis is stable
Vault is appropriate
The cornea is suitable
Refraction is stable
The expected benefit exceeds the risk

Halos and Glare

Patients may notice:

Rings around lights
Glare
Starbursts
Light streaks
Night-driving difficulty

Possible contributors include:

Central-port optics
Large pupils
Residual astigmatism
Toric misalignment
Dry eye
ICL edge reflections
Natural-lens reflections

Symptoms often become less noticeable with time.

Raised Eye Pressure

Eye pressure may rise because of:

Retained viscosurgical material
Steroid response
Pupillary block
High vault
Angle narrowing
Pigment dispersion
Inflammation

Symptoms may include:

Eye pain
Headache
Nausea
Halos
Blurred vision

A pressure rise may also cause no symptoms.

Pupillary Block

Modern central-port ICLs allow aqueous fluid to pass through the lens.

This substantially reduces the need for a preoperative iridotomy.

Pupillary block remains possible if:

The central port is obstructed
The lens is incorrectly positioned
Significant inflammatory material is present
The pupil or iris behaves abnormally

Pigment Dispersion

Excessive ICL contact with the back of the iris may release pigment.

Pigment may accumulate in the drainage system and contribute to:

Raised eye pressure
Pigment dispersion
Secondary glaucoma

Cataract Formation

The natural lens remains inside the eye and continues ageing.

Cataract may develop because of:

Normal age-related change
Low vault
Direct lens contact
Surgical trauma
Metabolic factors
Genetic predisposition

Modern central-port lenses appear to have reduced the risk of anterior subcapsular lens opacity compared with earlier designs, but they do not prevent ordinary age-related cataract.

What Happens if Cataract Develops?

Treatment usually involves:

Removing the Toric ICL
Removing the cloudy natural lens
Implanting a suitable cataract intraocular lens

The previous toric correction and corneal astigmatism are considered when selecting the cataract lens.

Endothelial Cell Loss

Some endothelial cell loss occurs after intraocular surgery.

Long-term monitoring is important because:

Endothelial cells decline naturally with age.
An ICL occupies space within the anterior segment.
High vault may bring the lens and iris complex forwards.
Additional intraocular surgery may cause further loss.

Infection

Endophthalmitis is a rare but serious infection inside the eye.

Possible symptoms include:

Increasing pain
Increasing redness
Worsening vision
Marked light sensitivity
Eyelid swelling
Discharge

Urgent treatment is required.

Inflammation

Mild inflammation is expected after surgery.

More significant inflammation may cause:

Pain
Light sensitivity
Blurred vision
Redness
Deposits on the ICL
Iris adhesions

Corneal Swelling

Temporary corneal swelling may occur because of:

Surgical manipulation
Raised eye pressure
Inflammation
Endothelial stress

Persistent swelling requires assessment.

ICL Decentration

The lens may not remain perfectly centred.

Minor decentration may cause no symptoms.

Significant decentration may contribute to:

Glare
Halos
Reduced optical quality
Vault asymmetry
Iris contact
Unstable toric correction

Retinal Risks

Toric ICL surgery corrects refractive error but does not shorten a myopic eyeball.

Patients remain at risk of:

Retinal tears
Retinal detachment
Myopic macular degeneration
Macular schisis

Urgent assessment is required for:

New flashes
A sudden shower of floaters
A curtain or shadow
Sudden visual loss

Does Toric ICL Cause Dry Eye?

Toric ICL causes less direct central corneal nerve disruption than LASIK, PRK or SMILE because the central cornea is not reshaped.

Temporary dryness may still occur because of:

Surgical drops
The corneal incision
Eyelid preparation
Reduced blinking
Pre-existing ocular-surface disease
Postoperative medication

Toric ICL Versus Spherical ICL with Glasses

A spherical ICL may correct the myopia while leaving astigmatism to be corrected with spectacles.

This may be reasonable when:

Astigmatism is minimal
Toric power is unavailable
The astigmatic measurement is unstable
The patient accepts spectacles

A Toric ICL generally provides better unaided vision when clinically significant regular astigmatism is present.

Toric ICL Versus LASIK

Possible Advantages of Toric ICL

No corneal stromal tissue removal
Suitable for higher myopic astigmatism
Preserves corneal shape
Removable or exchangeable
Potentially favourable optical quality
No LASIK flap

Possible Advantages of LASIK

No intraocular implant
No vault concern
No ICL-related cataract risk
No long-term implant-related endothelial monitoring
Rapid visual recovery
Easier enhancement

Toric ICL Versus SMILE

Possible Advantages of Toric ICL

No corneal tissue removal
Suitable for higher myopia
Direct toric correction
Less induction of corneal higher-order aberrations
Removable or exchangeable

Possible Advantages of SMILE

No intraocular surgery
No implant sizing
No vault issue
No ICL-related cataract risk
No toric lens that can rotate

SMILE astigmatism correction may be influenced by:

Cyclotorsion
Treatment centration
Corneal healing
Available treatment range

Toric ICL astigmatism correction is influenced more directly by lens-axis stability.

Toric ICL Versus PRK or TransPRK

Possible Advantages of Toric ICL

Faster early recovery
No epithelial defect
No corneal haze
No stromal tissue removal
Suitable for higher prescriptions

Possible Advantages of Surface Laser

No intraocular implant
No vault or sizing issue
No toric lens rotation
No ICL-related cataract concern
No intraocular surgical infection risk

Toric ICL Versus a Toric Cataract Lens

A Toric ICL preserves the natural crystalline lens and accommodation.

A toric cataract intraocular lens is implanted after the natural lens has been removed.

Toric cataract surgery may be more appropriate when:

A cataract is present
Presbyopia is advanced
Lens-related refractive change is occurring
The natural lens is likely to require removal soon

Can Toric ICL Correct Presbyopia?

A standard Toric ICL does not restore accommodation.

Patients may still require reading glasses as the natural lens ages.

Possible strategies include:

Both eyes corrected for distance
Mild monovision
Leaving one eye slightly short-sighted
Presbyopia-correcting phakic-lens designs where available

Can a Toric ICL Be Felt?

No.

The lens is positioned inside the eye behind the iris.

A persistent foreign-body sensation is more likely to arise from:

Dry eye
The corneal incision
Eyelid inflammation
A surface abrasion
Postoperative drops

Can the Lens Fall Out?

No.

The lens cannot fall out through ordinary activity.

It may rotate or move inside the eye if its anatomical fit is unsuitable.

Can I Rub My Eyes?

Eye rubbing should be avoided during early recovery.

Long-term vigorous rubbing is also discouraged because it may:

Irritate the ocular surface
Worsen allergy
Cause trauma
Affect susceptible corneas

When Can I Exercise?

Gentle walking is generally possible early.

Strenuous exercise, heavy lifting and contact sports may need to be avoided temporarily.

When Can I Swim?

Swimming is usually avoided during early healing because water may contain:

Bacteria
Parasites
Chemicals
Irritants

When Can I Use Screens?

Screens do not damage or rotate the Toric ICL.

Prolonged screen use may worsen dryness because blinking decreases.

When Can I Drive?

Driving should resume only when:

Vision meets the legal requirement
The patient feels confident
Glare is manageable
Depth perception is satisfactory
Sedative effects have resolved
The surgeon has not advised otherwise

When Can I Fly?

Routine uncomplicated Toric ICL surgery does not place gas inside the eye and usually does not prevent flying.

Travel should not interfere with:

Early postoperative reviews
Eye-pressure checks
Assessment of axis and vault
Access to urgent care

Common Myths

“Toric ICL Is Only a Stronger Version of an Ordinary ICL”

Incomplete.

It contains a cylindrical correction that must be aligned accurately.

“Once the Correct Power Is Chosen, the Axis Does Not Matter”

False.

Rotation reduces the effective astigmatic correction.

“A Few Degrees of Rotation Never Matter”

False.

The effect depends on the amount of rotation and the cylinder power.

“Residual Astigmatism Always Means the Lens Rotated”

False.

Other causes include inaccurate refraction, posterior corneal astigmatism, surgically induced astigmatism and irregular corneal optics.

“A Toric ICL Cannot Rotate”

False.

Modern lenses are generally stable, but clinically significant rotation can occur.

“The Lens Can Simply Be Rotated Vertically to Reduce High Vault”

Not necessarily.

Rotating a Toric ICL away from its planned optical axis may create significant residual astigmatism.

“Toric ICL Treats Keratoconus”

False.

It corrects refractive error but does not strengthen or regularise the cornea.

“Toric ICL Is Completely Reversible”

Misleading.

The lens is removable, but the eye has undergone intraocular surgery.

“Toric ICL Prevents Presbyopia”

False.

The natural lens continues ageing.

“Toric ICL Prevents Cataract”

False.

The natural lens can still develop cataract.

“Toric ICL Removes Retinal Risks”

False.

A highly myopic eye remains anatomically myopic.

“Toric ICL Never Needs Follow-Up”

False.

The lens axis, vault, eye pressure, natural lens and endothelial cells require monitoring.

Frequently Asked Questions

Can Toric ICL Correct All Astigmatism?

It is designed primarily for regular refractive astigmatism within the available lens range.

It may not fully correct:

Severe irregular astigmatism
Unstable astigmatism
Astigmatism caused by active keratoconus
Highly asymmetric corneal disease

What Happens if My Cylinder Falls Between Available Lens Powers?

The surgeon selects the lens expected to provide the best overall result.

A small residual cylinder may remain.

Can Both Eyes Have Different Toric Powers?

Yes.

Each eye has its own:

Spherical power
Cylinder power
Axis
Lens size
Anatomical measurements

Can Both Eyes Have Different Axes?

Yes.

Astigmatism axis commonly differs between the eyes.

Can Both Eyes Have Different ICL Sizes?

Yes.

Each eye is measured and planned separately.

Can One Eye Have a Toric ICL and the Other a Spherical ICL?

Yes.

This may occur when only one eye has clinically significant astigmatism.

Can the Axis Be Checked Without Dilating the Pupil?

The Toric ICL marks may sometimes be assessed through an undilated pupil.

Dilation may provide a clearer view.

Can the Lens Rotate Years Later?

Late rotation is uncommon but possible.

New blur or ghosting should be assessed rather than assumed to be dry eye or prescription change.

Can the Lens Be Realigned?

Yes.

Surgical realignment is usually possible.

How Soon Should a Rotated Lens Be Repositioned?

The timing depends on:

Degree of rotation
Symptoms
Residual cylinder
Lens stability
Eye pressure
Corneal and anterior-chamber condition

A clinically significant, clearly documented rotation is generally addressed after confirming the intended axis and excluding measurement error.

Can a Rotated Lens Rotate Again?

Yes.

Recurrent rotation may suggest an anatomical-fit or sizing problem.

Lens exchange may then be considered.

Can Laser Surgery Correct Residual Astigmatism?

Possibly.

The cornea must still be suitable for laser treatment.

The Toric ICL should first be confirmed to be:

Correctly aligned
Stable
Appropriately vaulted

Can ICL Surgery Improve Vision Beyond My Glasses?

Some high-myopic patients gain corrected visual-acuity lines because an internal lens avoids the image minification caused by strong minus spectacles.

Improvement is possible but cannot be guaranteed.

Can Toric ICL Cause Halos?

Yes.

Halos and rings around lights are recognised symptoms after ICL surgery.

Residual astigmatism or rotation may make them more noticeable.

Can I See the Central Port?

Most patients do not directly see it.

Some may perceive rings or halos in particular lighting.

Does the Lens Need Cleaning?

No.

The lens is inside the eye and does not require manual cleaning.

Can I Wear Contact Lenses After Toric ICL?

Yes, if necessary.

Possible reasons include:

Residual refractive error
Irregular astigmatism
Special visual tasks

Can I Have Cataract Surgery Later?

Yes.

The Toric ICL is usually removed during cataract surgery.

The cataract surgeon then selects an appropriate intraocular lens.

Can Toric ICL Treat Lazy Eye?

No.

It corrects optical refractive error but cannot reverse amblyopia established during childhood.

Does Toric ICL Change Eye Colour?

No.

The iris is not altered.

Can Toric ICL Cause Blindness?

Severe permanent visual loss is rare but possible.

Potential causes include:

Infection
Uncontrolled glaucoma
Severe endothelial failure
Retinal complications
Major inflammation
Other unrelated ocular disease

When to Seek Urgent Eye Care

Seek urgent assessment for:

Increasing eye pain
Increasing redness
Rapidly worsening vision
Severe headache
Nausea or vomiting
Marked halos associated with pain
Thick discharge
Significant light sensitivity
Sudden blur after initially clear vision
New ghosting or distortion
New flashes
A sudden shower of floaters
A curtain or shadow
Eye trauma

These symptoms may indicate:

Raised eye pressure
Infection
Significant inflammation
Toric lens rotation
Retinal tear or detachment
Another ocular emergency

A Toric ICL Assessment Checklist

Visual Goals to Discuss

Distance vision
Reading vision
Computer vision
Night driving
Contact sports
Occupation
Spectacle independence
Tolerance of halos
Future presbyopia

Medical Information to Report

Diabetes
Autoimmune disease
Pregnancy or breastfeeding
Medication
Allergies
Previous healing problems
Family history of glaucoma

Eye History to Report

Previous LASIK, PRK, TransPRK or SMILE
Keratoconus
Corneal cross-linking
Glaucoma
Uveitis
Cataract
Retinal tear or detachment
Eye trauma
Contact-lens intolerance
Previous ICL surgery

Measurements That May Be Required

Manifest refraction
Cycloplegic refraction
Corneal topography
Corneal tomography
Anterior-chamber depth
White-to-white diameter
Anterior-segment OCT
Ultrasound biomicroscopy
Endothelial cell count
Eye pressure
Drainage-angle assessment
Pupil size
Dilated retinal examination

Questions to Ask the Surgeon

Is my astigmatism regular and stable?
Why is a Toric ICL recommended?
What spherical and cylindrical powers are planned?
What is the intended axis?
How will cyclotorsion be controlled?
Will manual or digital marking be used?
How was the lens size selected?
What vault is expected?
How will the axis be checked after surgery?
What degree of rotation would require treatment?
What happens if the lens rotates?
Could recurrent rotation require lens exchange?
What is my endothelial cell count?
What is my risk of cataract?
What is my risk of raised eye pressure?
How likely are halos?
Could residual astigmatism be treated with laser?
How frequently will I need long-term review?
Which symptoms require urgent assessment?

The Bottom Line

A Toric Implantable Collamer Lens is positioned behind the iris and in front of the natural crystalline lens.

It corrects:

Myopia
Regular astigmatism

Potential advantages include:

No corneal stromal tissue removal
Correction of high myopic astigmatism
Preservation of corneal shape
Good optical quality
Rapid visual recovery
Removal or exchange when necessary

Possible disadvantages include:

Intraocular surgery
Need for accurate lens sizing
Need for precise toric-axis alignment
Possibility of rotation
Lifelong monitoring
Halos or glare
Risk of cataract
Risk of raised eye pressure
Endothelial cell loss

The defining additional consideration with a Toric ICL is rotational stability.

A lens with the correct spherical and cylindrical powers may not provide the expected unaided vision if it rotates away from its planned axis.

Residual astigmatism should therefore be evaluated by checking:

Manifest refraction
Corneal measurements
Toric lens axis
Vault
Lens centration
Ocular-surface quality

Modern Toric ICLs generally demonstrate favourable rotational stability and long-term refractive outcomes. Nevertheless, a small proportion of lenses require surgical realignment or exchange.

The most important message is:

Toric ICL surgery depends on the combination of accurate astigmatism measurement, careful lens-power calculation, appropriate anatomical sizing, precise axis marking, suitable vault and long-term monitoring. Correct lens power alone is not enough—the lens must also remain correctly oriented inside the eye.

References

Yang Y, et al. Rotational stability and outcomes of V4c toric Implantable Collamer Lenses placed at different lens orientations. J Refract Surg. 2025;41(1)–e38. PMID: 39783815.
Kamiya K, et al. Evaluation of long-term clinical outcomes after toric Implantable Collamer Lens implantation. J Cataract Refract Surg. 2023. PMID: 37395497.
Lee H, Kang DSY, Choi JY, et al. Rotational stability and visual outcomes of V4c toric phakic intraocular lenses. J Refract Surg. 2018;34(7):489–496. PMID: 30001453.
Sanders DR, Schneider D, Martin R, et al. Toric Implantable Collamer Lens for moderate-to-high myopic astigmatism. Ophthalmology. 2007;114(1):54–61.
Kamiya K, Shimizu K, Igarashi A, Komatsu M. Comparison of Collamer toric implantable contact lens implantation and wavefront-guided LASIK for high myopic astigmatism. J Refract Surg. 2008.
Larivoir NB, Ribeiro ACS, Morgado CR, Santhiago MR. Efficacy, predictability and safety of phakic Implantable Collamer Lenses V4c and V5: a systematic review and meta-analysis. J Refract Surg. 2025. PMID: 41369665.
Packer M. The Implantable Collamer Lens with a central port: review of the literature. Clin Ophthalmol. 2018;12:2427–2438. PMID: 30568421.
Packer M. Meta-analysis and review: effectiveness, safety and central-port design of the intraocular Collamer lens. Clin Ophthalmol. 2016;10:1059–1077. PMID: 27354760.
Packer M, et al. Implantable Collamer Lens procedure planning: a review of global approaches. 2024. PMID: 38601168.
Kojima T, Yokoyama S, Ito M, Horai R, Hara S, Nakamura T. Optimisation of an Implantable Collamer Lens sizing method using high-frequency ultrasound biomicroscopy. Am J Ophthalmol. 2012. PMID: 22245462.
Nakamura T, Isogai N, Kojima T, Yoshida Y, Sugiyama Y. Implantable Collamer Lens sizing method based on swept-source anterior-segment optical coherence tomography. Am J Ophthalmol. 2018. PMID: 29294311.
Alfonso-Bartolozzi B, Fernández-Vega-Cueto L, Lisa C, et al. Ten-year follow-up of posterior-chamber phakic intraocular lenses with central-port design in eyes with low and normal vault. J Cataract Refract Surg. 2024;50(5):441–447. PMID: 38085219.
Kisiel FB, Gurumurthy GJ. Endothelial cell loss after Implantable Collamer Lens V4c implantation: a meta-analysis. J Cataract Refract Surg. 2024;50(4):420–423. PMID: 38194352.
Shimizu K, et al. Eight-year outcomes of posterior-chamber phakic intraocular lens implantation with a central port for moderate-to-high ametropia. PMID: 34977099.
Chen D, et al. Implantable Collamer Lens versus small-incision lenticule extraction for high-myopia correction: a systematic review and meta-analysis. PMID: 34961514.
Li M, et al. Two-year visual outcomes of EVO Implantable Collamer Lens and small-incision lenticule extraction for correction of low myopia. PMID: 35492322.
Wei R, et al. Visual outcomes after SMILE and Implantable Collamer Lens V4c implantation for moderate myopia: one-year results. Graefes Arch Clin Exp Ophthalmol. 2021. PMID: 33661364.
Fernandes P, González-Méijome JM, Madrid-Costa D, Ferrer-Blasco T, Jorge J, Montés-Micó R. Implantable Collamer posterior-chamber intraocular lenses: a review of potential complications. J Refract Surg. 2011;27:765–776.
Sanders DR, Doney K, Poco M; ICL in Treatment of Myopia Study Group. United States Food and Drug Administration clinical trial of the Implantable Collamer Lens for moderate-to-high myopia: three-year follow-up. Ophthalmology. 2004;111(9):1683–1692. PMID: 15350323.
Alpins N. A new method of analysing vectors for changes in astigmatism. J Cataract Refract Surg. 1993;19(4):524–533.