Laser Glaucoma Treatment: Types, Suitability, Risks and Recovery

Author: Dr Val Phua
Estimated reading time: 22 minutes

Laser treatment is an important part of modern glaucoma care.

Depending on the type of glaucoma and the anatomy of the eye, laser may be used to:

• Improve the drainage of fluid from the eye
• Open a narrow or blocked drainage angle
• Reduce fluid production inside the eye
• Lower intraocular pressure
• Reduce dependence on glaucoma eye drops
• Delay or reduce the need for glaucoma surgery
• Treat an acute or potentially dangerous angle-closure mechanism

The term laser glaucoma treatment does not refer to one procedure.

Several different lasers and treatment strategies are used, including:

• Selective laser trabeculoplasty
• Argon laser trabeculoplasty
• Laser peripheral iridotomy
• Laser peripheral iridoplasty
• Micropulse laser trabeculoplasty
• Transscleral cyclophotocoagulation
• Micropulse transscleral laser treatment
• Slow-coagulation cyclophotocoagulation
• Endoscopic cyclophotocoagulation

Each treatment targets a different part of the eye.

Laser treatment may be performed as:

• The first treatment for glaucoma
• An alternative to eye drops
• An additional treatment when drops are insufficient
• A treatment after previous glaucoma surgery
• An urgent procedure for angle closure
• A procedure for advanced or painful glaucoma

The most commonly used laser for open-angle glaucoma is selective laser trabeculoplasty, or SLT.

Large randomised trials support SLT as a safe and effective first-line treatment for open-angle glaucoma and ocular hypertension. In the six-year LiGHT trial, approximately 70% of eyes initially treated with SLT remained at target pressure without glaucoma medication or incisional surgery, and disease progression and trabeculectomy were less frequent than in eyes initially treated with drops.

Laser treatment does not restore optic-nerve tissue that has already been lost.

Its purpose is to reduce the risk of further glaucomatous damage by controlling intraocular pressure and, where relevant, correcting an abnormal drainage mechanism.

The Quick Answer

What Is Glaucoma?

Glaucoma is a group of eye diseases that damage the optic nerve.

The damage is often associated with intraocular pressure that is too high for that individual optic nerve.

Glaucoma may cause:

• Progressive loss of peripheral vision
• Difficulty seeing in dim lighting
• Reduced contrast
• Loss of central vision in advanced disease
• Permanent blindness if severe disease remains uncontrolled

Early glaucoma commonly causes no noticeable symptoms.

What Does Laser Glaucoma Treatment Do?

The effect depends on the procedure.

Laser may:

• Improve fluid drainage through the trabecular meshwork
• Create an opening in the peripheral iris
• Contract the peripheral iris to widen the drainage angle
• Reduce aqueous-fluid production by treating the ciliary body

Can Laser Cure Glaucoma?

No.

Laser can lower eye pressure or correct an anatomical mechanism, but the patient still has glaucoma or remains at risk of developing it.

Continued monitoring is required.

Can Laser Restore Lost Vision?

No.

Vision already lost from glaucomatous optic-nerve damage usually cannot be restored.

Laser aims to preserve remaining vision.

Is Laser Better Than Eye Drops?

Neither option is universally better.

For many patients with newly diagnosed open-angle glaucoma or ocular hypertension, SLT is an effective first-line alternative to drops. It avoids daily adherence and medication-related ocular-surface effects, although its pressure-lowering effect can diminish and additional treatment may eventually be required.

Is Laser Painful?

Most glaucoma laser procedures cause little or no sharp pain.

Patients may notice:

• Pressure from the contact lens
• Bright flashes
• Mild stinging
• A temporary ache
• Headache
• Light sensitivity

Cyclophotocoagulation may require stronger local anaesthesia, sedation or general anaesthesia because it treats the ciliary body through or inside the eye.

How Long Does Laser Treatment Take?

The laser portion commonly takes approximately 5 to 20 minutes.

Additional time is needed for:

• Eye-pressure measurements
• Preparation
• Anaesthetic drops
• Pupil constriction or dilation
• Post-laser monitoring
• Medication

How Quickly Does Laser Lower Eye Pressure?

This depends on the procedure.

SLT commonly takes several weeks to reach its full effect.

Laser peripheral iridotomy changes the pupil-block mechanism immediately, although the drainage angle and eye pressure still require reassessment.

Cyclophotocoagulation may begin lowering pressure within days, but its final effect may take several weeks.

Understanding Intraocular Pressure

How Is Fluid Produced?

A clear fluid called aqueous humour is produced by the ciliary body behind the iris.

It normally flows:

• Through the pupil
• Into the anterior chamber
• Through the trabecular meshwork
• Into Schlemm’s canal
• Into the venous circulation

What Causes Pressure to Rise?

Eye pressure may increase when:

• The trabecular meshwork does not drain effectively
• The iris blocks the drainage angle
• Scar tissue closes the angle
• Inflammation or pigment obstructs drainage
• Abnormal blood vessels cover the angle
• Fluid production exceeds drainage
• Previous surgery or injury alters eye anatomy

What Is the Target Eye Pressure?

The target pressure is the level judged sufficiently low to reduce the risk of further optic-nerve damage.

It depends on:

• Starting pressure
• Severity of glaucoma
• Rate of progression
• Corneal thickness
• Age
• Life expectancy
• Optic-nerve appearance
• Visual-field damage
• Other risk factors

A pressure considered normal for one person may still be too high for another.

The Main Types of Laser Glaucoma Treatment

Selective Laser Trabeculoplasty

SLT treats the trabecular meshwork in open-angle glaucoma.

It stimulates biological changes that improve aqueous drainage.

Argon Laser Trabeculoplasty

ALT also treats the trabecular meshwork but causes small thermal burns and structural contraction.

It has largely been replaced by SLT in many centres.

Laser Peripheral Iridotomy

LPI creates a small opening in the peripheral iris.

It is used principally for pupil-block-related angle closure.

Laser Peripheral Iridoplasty

Iridoplasty applies contraction burns to the far peripheral iris to pull it away from the drainage angle.

Transscleral Cyclophotocoagulation

This treatment applies laser through the sclera to reduce aqueous production by the ciliary body.

Endoscopic Cyclophotocoagulation

ECP treats the ciliary processes directly from inside the eye using an endoscope.

Selective Laser Trabeculoplasty

What Is SLT?

Selective laser trabeculoplasty is a pressure-lowering treatment for eyes with an accessible drainage angle.

A short-pulsed laser targets pigmented cells within the trabecular meshwork.

The energy is absorbed selectively by pigment-containing cells while producing relatively little thermal damage to surrounding tissue.

SLT uses substantially less energy than ALT and causes less structural injury to the trabecular meshwork.

How Does SLT Lower Pressure?

The exact mechanism is complex.

The laser appears to stimulate:

• Cellular signalling
• Release of inflammatory mediators
• Macrophage recruitment
• Remodelling of the trabecular extracellular matrix
• Improved drainage through Schlemm’s canal

SLT does not drill physical drainage holes through the meshwork.

Who May Be Suitable for SLT?

SLT may be considered for:

• Primary open-angle glaucoma
• Ocular hypertension
• Normal-tension glaucoma
• Pseudoexfoliative glaucoma
• Pigmentary glaucoma
• Selected secondary open-angle glaucomas
• Some angle-closure eyes after iridotomy if sufficient trabecular meshwork is visible

Can SLT Be the First Treatment?

Yes.

The American Academy of Ophthalmology review concluded that high-level evidence supports SLT as:

• Primary treatment
• A replacement for medication
• Additional treatment alongside drops

The six-year LiGHT trial found better long-term disease control and less need for incisional glaucoma surgery when SLT was used as initial therapy rather than beginning with drops.

Why Might SLT Be Chosen Before Drops?

Possible advantages include:

• No daily treatment burden
• No risk of forgetting doses
• Less exposure to preservatives
• Reduced ocular-surface toxicity
• Avoidance of some systemic medication effects
• Potentially several years of pressure control
• Ability to repeat treatment in selected eyes
• No permanent surgical implant

Why Might Drops Still Be Preferred?

Drops may be preferred when:

• Immediate titration is required
• The angle cannot be visualised adequately
• The trabecular meshwork is inaccessible
• Previous SLT produced a severe pressure spike
• Active inflammation is present
• The patient declines laser
• The desired target pressure is unlikely to be achieved with SLT alone

How Is SLT Performed?

Step 1: Checking the Drainage Angle

Gonioscopy is performed to confirm that the trabecular meshwork is visible and suitable for treatment.

Step 2: Preparing the Eye

Anaesthetic drops are applied.

An eye-pressure-lowering drop may be given before or immediately after treatment to reduce the risk of a temporary pressure spike.

Step 3: Placing the Contact Lens

A special gonioscopy lens is placed on the eye.

The lens:

• Keeps the eyelids apart
• Magnifies the drainage angle
• Directs the laser beam
• Stabilises the eye

Step 4: Applying the Laser

Laser spots are applied around part or all of the trabecular meshwork.

The patient may see:

• Bright flashes
• Coloured lights
• Brief dimming

Step 5: Checking Eye Pressure

Eye pressure may be checked after the procedure, particularly in patients at greater risk of an acute pressure rise.

Is 360-Degree SLT Better Than 180-Degree SLT?

SLT may treat:

• 90 degrees
• 180 degrees
• 270 degrees
• 360 degrees of the angle

Recent systematic reviews found that 360-degree treatment generally provides greater and more durable pressure reduction than 180-degree treatment without a significant increase in serious complications. Treatment extent is nevertheless individualised according to pigmentation, previous laser and pressure-spike risk.

How Effective Is SLT?

The pressure response varies.

A clinically useful response is often defined as an eye-pressure reduction of approximately 20% or more.

The effect is influenced by:

• Baseline eye pressure
• Type of glaucoma
• Degree of angle pigmentation
• Previous treatment
• Extent of laser
• Individual biological response

Higher starting pressure generally provides a greater opportunity for absolute pressure reduction.

SLT is less likely to produce a large numerical reduction when the untreated pressure is already low, as in some normal-tension glaucoma patients.

How Long Does SLT Last?

The effect may last:

• Several months
• Several years
• Longer in some patients

Its effectiveness may gradually diminish.

The patient may then require:

• Repeat SLT
• Eye drops
• Another laser
• Minimally invasive glaucoma surgery
• Trabeculectomy or drainage-device surgery

Can SLT Be Repeated?

Yes, in selected patients.

Repeat SLT can produce additional pressure lowering when the first treatment was initially successful but later wore off.

Systematic reviews support repeat SLT as a useful option with generally low complication rates, although the response is not guaranteed and may be smaller or shorter than the original response.

Does SLT Work Immediately?

Not usually.

Some pressure change may occur within days, but the full effect commonly takes approximately four to six weeks.

Existing glaucoma medication is usually continued unless the ophthalmologist advises otherwise.

Risks of SLT

Possible complications include:

• Temporary eye-pressure elevation
• Mild inflammation
• Redness
• Aching
• Light sensitivity
• Temporary blurred vision
• Corneal swelling
• Small anterior-chamber bleeding
• Inflammation of a previously quiet eye
• Rare macular oedema
• Rare sustained pressure rise
• Failure to lower pressure

Most adverse effects are mild and self-limiting. Pressure spikes and inflammation are the most common recognised complications, and heavily pigmented angles may carry a greater pressure-spike risk.

SLT in Pigmentary and Pseudoexfoliative Glaucoma

SLT may work well in eyes with a heavily pigmented trabecular meshwork.

However, greater pigment absorption may increase the risk of:

• Excessive inflammation
• A significant early pressure spike

The surgeon may therefore modify:

• Laser energy
• Treatment extent
• Pre-laser medication
• Post-laser monitoring

Argon Laser Trabeculoplasty

What Is ALT?

Argon laser trabeculoplasty applies thermal burns to the trabecular meshwork.

The burns cause:

• Local tissue contraction
• Mechanical stretching of adjacent meshwork
• Biological remodelling

Is ALT Still Used?

ALT remains effective, but SLT has replaced it in many settings because SLT:

• Uses less energy
• Produces less structural tissue damage
• Is more suitable for repeat treatment
• Has comparable long-term pressure-lowering efficacy

High-level evidence indicates that SLT and ALT are broadly equivalent in safety and long-term effectiveness, although their tissue effects differ.

Can ALT Be Repeated?

Repeat ALT is more limited because the treatment causes permanent thermal scarring.

Micropulse Laser Trabeculoplasty

What Is MLT?

Micropulse laser trabeculoplasty delivers laser energy as short bursts separated by rest periods.

The aim is to produce a biological response while reducing continuous thermal injury.

Is MLT Better Than SLT?

Current comparative evidence suggests that MLT and SLT can both lower pressure in open-angle glaucoma.

Recent meta-analyses have not established clear overall superiority of MLT, and SLT has a larger evidence base and more established long-term data.

Direct Selective Laser Trabeculoplasty

What Is Direct SLT?

Direct SLT applies laser through the limbus without using a gonioscopy contact lens.

The system automatically targets the trabecular region from outside the eye.

Potential advantages include:

• No contact lens
• Short treatment time
• Less operator dependence
• Potentially easier treatment delivery

Long-term comparative evidence remains less extensive than for conventional gonioscopy-guided SLT.

Laser Peripheral Iridotomy

What Is LPI?

Laser peripheral iridotomy creates a small full-thickness opening in the peripheral iris.

The opening allows aqueous fluid to pass directly from behind the iris into the anterior chamber.

This equalises pressure across the iris and reduces forward bowing caused by pupil block.

What Is Pupil Block?

Aqueous fluid normally flows through the pupil.

When flow is restricted between the iris and natural lens:

• Pressure increases behind the iris.
• The peripheral iris bows forwards.
• The drainage angle becomes narrow or closes.
• Eye pressure may rise suddenly or gradually.

LPI bypasses the blocked pupil pathway.

Who May Need LPI?

LPI may be recommended for:

• Acute primary angle closure
• The fellow eye after an acute angle-closure attack
• Primary angle closure
• Primary angle-closure glaucoma
• Selected primary angle-closure suspects
• Iris bombe from posterior synechiae
• Certain secondary pupil-block mechanisms
• Preparation for some phakic intraocular lenses without a central port

Does Every Narrow Angle Require LPI?

No.

Large randomised trials in asymptomatic primary angle-closure suspects found that LPI reduced progression to primary angle closure, but the untreated event rate was relatively low.

The five-year Singapore ANA-LIS trial found progression in 5.0% of treated eyes compared with 9.4% of untreated fellow eyes. The clinical decision therefore depends on the individual risk of angle closure rather than the presence of a narrow angle alone.

Factors that may support prophylactic LPI include:

• Very narrow or occludable angles
• Elevated eye pressure
• Peripheral anterior synechiae
• Symptoms suggestive of intermittent angle closure
• A strong family history
• Limited access to emergency eye care
• Frequent pupil dilation
• Use of medication that may dilate the pupil
• Fellow-eye acute angle closure
• A higher-risk anatomical profile

Does LPI Always Open the Angle Completely?

No.

LPI corrects the pupil-block component.

The angle may remain narrow because of:

• Plateau iris
• A large or forward-positioned natural lens
• Thick peripheral iris
• Anteriorly positioned ciliary processes
• Peripheral anterior synechiae
• Other non-pupil-block mechanisms

A 2026 analysis from the Singapore ANA-LIS cohort found persistent gonioscopic closure in approximately one-third of treated eyes after five years, reinforcing the need for repeat gonioscopy after apparently successful LPI.

How Is LPI Performed?

Step 1: Constricting the Pupil

Pilocarpine may be used to:

• Constrict the pupil
• Stretch and thin the peripheral iris
• Facilitate laser penetration

It may cause:

• Brow ache
• Headache
• Temporary blurred distance vision

Step 2: Lowering Pressure Risk

An eye-pressure-lowering drop may be given before treatment.

Step 3: Applying Anaesthetic Drops

The surface of the eye is numbed.

Step 4: Placing the Contact Lens

A specialised iridotomy lens is placed on the cornea.

Step 5: Creating the Opening

A laser opening is created in the peripheral iris.

The treatment may use:

• Nd laser
• Argon laser followed by Nd
• Another device-specific sequence

Step 6: Confirming Patency

The ophthalmologist confirms that the opening passes completely through the iris.

Step 7: Checking Eye Pressure

Eye pressure may be rechecked after treatment.

Risks of LPI

Possible complications include:

• Temporary eye-pressure rise
• Mild inflammation
• Small iris bleeding
• Corneal injury
• Lens injury
• Closure of the iridotomy
• Need for repeat treatment
• Glare
• Lines or arcs of light
• Monocular double images
• Persistent narrow angles
• Rare retinal or macular complications

The American Academy of Ophthalmology review found that LPI generally widens the angle and has a favourable safety profile, although pressure spikes, bleeding and dysphotopsias are recognised.

Visual Symptoms After LPI

Some patients notice:

• A horizontal line
• A crescent
• Ghosting
• Glare
• Light entering from above or the side

These symptoms are called dysphotopsias.

A 2024 systematic review did not establish a simple universal relationship between iridotomy location and visual symptoms.

LPI and Acute Angle Closure

Acute angle closure is an emergency.

Symptoms may include:

• Severe eye pain
• Red eye
• Blurred vision
• Halos
• Headache
• Nausea
• Vomiting

Initial medication is often required to lower pressure and clear the cornea before LPI can be completed.

LPI is then used to relieve pupil block in the affected eye and commonly to protect the fellow eye.

LPI Versus Cataract Surgery

LPI creates a bypass through the iris but leaves the natural lens in place.

Cataract or clear-lens extraction:

• Removes the bulky natural lens
• Deepens the anterior chamber
• Widens the drainage angle
• May provide greater pressure reduction in selected angle-closure eyes

Lens extraction may be more appropriate when:

• A cataract is present
• The lens is a major cause of angle crowding
• Angle-closure glaucoma is established
• Eye pressure remains uncontrolled after LPI
• Visual function is limited by the lens

LPI and cataract surgery are therefore not interchangeable procedures.

Laser Peripheral Iridoplasty

What Is Iridoplasty?

Laser peripheral iridoplasty applies low-energy contraction burns to the extreme peripheral iris.

The treated iris contracts and pulls away from the drainage angle.

When Is Iridoplasty Used?

It may be considered for:

• Plateau-iris configuration
• Persistent appositional angle closure after LPI
• Acute angle closure when LPI cannot initially be performed
• Selected eyes in which the peripheral iris remains crowded

Does Iridoplasty Replace LPI?

Usually not when pupil block is present.

LPI addresses pressure behind the iris.

Iridoplasty changes peripheral iris shape.

The procedures may be complementary.

How Effective Is Iridoplasty?

Iridoplasty can widen the angle anatomically, but long-term pressure control is variable.

A Singapore randomised trial found limited one-year complete success when iridoplasty was compared with medical therapy in eyes with persistent angle closure after LPI. Evidence is therefore less robust than for SLT or LPI, and patient selection is important.

Cyclophotocoagulation

What Is Cyclophotocoagulation?

Cyclophotocoagulation lowers pressure by treating the ciliary body, which produces aqueous fluid.

Traditional cyclophotocoagulation was often reserved for:

• Advanced glaucoma
• Painful blind eyes
• Eyes with poor visual potential
• Glaucoma after failed surgery

Modern micropulse and slow-coagulation techniques are increasingly considered earlier in selected seeing eyes because they aim to reduce collateral tissue damage.

Continuous-Wave Transscleral Cyclophotocoagulation

How Does Continuous-Wave Treatment Work?

A diode-laser probe is placed against the sclera over the ciliary body.

Continuous laser energy produces coagulative treatment of the ciliary processes.

This reduces aqueous-fluid production.

Who May Need It?

It may be considered for:

• Refractory glaucoma
• Neovascular glaucoma
• Glaucoma after multiple failed operations
• Eyes with silicone oil
• Congenital or developmental glaucoma
• Painful glaucoma
• Eyes in which filtration surgery is unsuitable
• Eyes requiring substantial pressure reduction

How Is It Performed?

Treatment often requires:

• Local anaesthetic injection
• Sedation
• General anaesthesia in selected patients

The probe is moved around the eye while avoiding:

• The 3 and 9 o’clock meridians
• Areas of thin sclera
• Previous filtering blebs
• Drainage-device tubes
• Certain surgical scars

Risks of Continuous-Wave Cyclophotocoagulation

Possible complications include:

• Pain
• Inflammation
• Reduced vision
• Hypotony
• Choroidal detachment
• Macular oedema
• Bleeding
• Cataract progression
• Phthisis bulbi
• Sympathetic ophthalmia, very rarely
• Need for repeat treatment

The risks are influenced by:

• Total energy
• Number of treatment spots
• Previous surgery
• Glaucoma type
• Visual potential
• Individual tissue response

Micropulse Transscleral Laser Treatment

What Is Micropulse Cyclophotocoagulation?

Micropulse transscleral laser treatment delivers laser in repeated short bursts separated by rest periods.

The off periods allow tissue to cool.

The probe is swept across the ciliary-body region rather than creating individual stationary continuous-wave burns.

Why Is Micropulse Used?

The aim is to lower eye pressure while reducing the risk of:

• Excessive ciliary-body destruction
• Prolonged inflammation
• Hypotony
• Severe vision loss
• Phthisis

A 2025 meta-analysis found similar pressure control between micropulse and continuous-wave treatment, while micropulse was associated with lower risks of hypotony, prolonged inflammation and phthisis. It sometimes required more medication or repeat treatment.

Can Micropulse Treatment Be Repeated?

Yes.

Repeat treatment may be considered when:

• The original response was incomplete
• The effect diminishes
• The eye remains anatomically suitable
• The expected benefit exceeds the cumulative risk

Slow-Coagulation Cyclophotocoagulation

What Is Slow Coagulation?

Slow-coagulation cyclophotocoagulation uses lower power over a longer duration at each treatment location.

The aim is to create controlled ciliary-body treatment without the audible tissue “pops” associated with excessive rapid heating.

Evidence is evolving, and optimal energy settings remain under investigation.

A 2026 systematic review found slow-coagulation, conventional continuous-wave and micropulse methods had differing balances between pressure reduction, retreatment and complications; no single protocol is ideal for every glaucoma type.

Endoscopic Cyclophotocoagulation

What Is ECP?

Endoscopic cyclophotocoagulation treats the ciliary processes from inside the eye.

A small camera and laser probe allow the surgeon to see the ciliary processes directly.

When Is ECP Performed?

ECP may be performed:

• At the time of cataract surgery
• Through a limbal incision in an eye with an intraocular lens
• Through the pars plana in selected complex eyes
• As part of a combined glaucoma procedure

What Are the Potential Advantages?

Possible advantages include:

• Direct visualisation of the treatment
• Controlled treatment endpoint
• Avoidance of laser transmission through the sclera
• Ability to combine treatment with cataract surgery

What Are the Limitations?

ECP is intraocular surgery.

Possible risks include:

• Inflammation
• Bleeding
• Eye-pressure spikes
• Cystoid macular oedema
• Hypotony
• Retinal complications
• Infection
• Reduced vision

Systematic reviews suggest that ECP may lower pressure and medication requirements, especially when combined with cataract surgery, but the comparative randomised evidence is less extensive than for SLT.

Choosing the Correct Laser

Open-Angle Glaucoma

The main laser option is usually SLT.

Narrow or Closed Angles

Possible treatments include:

• LPI
• Iridoplasty
• Cataract or lens extraction
• SLT after the angle has opened sufficiently
• Cyclophotocoagulation in refractory disease

Refractory or Advanced Glaucoma

Possible treatments include:

• Micropulse transscleral laser
• Slow-coagulation cyclophotocoagulation
• Continuous-wave cyclophotocoagulation
• ECP
• Incisional glaucoma surgery

Painful Blind Eye

Cyclophotocoagulation may be used to lower pressure and reduce pain.

Laser Treatment Versus Eye Drops

Advantages of Laser

• No daily adherence
• No bottle-handling difficulty
• Less preservative exposure
• Fewer medication interactions
• Reduced long-term drop burden
• Potentially several years of control

Advantages of Drops

• No laser procedure
• Easy to start or stop
• Dose can be adjusted
• Different drug classes can be combined
• Useful when laser is contraindicated or insufficient

Limitations of Both

Neither treatment guarantees lifelong control.

Glaucoma may still progress because:

• The pressure target was insufficiently low
• Pressure fluctuates
• Treatment effect diminishes
• The optic nerve remains vulnerable
• Medication adherence is imperfect
• Another pressure-independent risk factor is present

Laser Treatment Versus Glaucoma Surgery

Laser is generally less invasive than:

• Trabeculectomy
• Glaucoma drainage-device surgery
• Subconjunctival stent surgery

However, incisional surgery may achieve a lower target pressure.

Surgery may be recommended when:

• Glaucoma is advanced
• Pressure remains above target
• Visual fields continue worsening
• Medication and laser are inadequate
• Very low pressure is required
• The drainage angle is extensively scarred

The Pre-Laser Assessment

Medical and Eye History

Important information includes:

• Type of glaucoma
• Previous laser treatment
• Previous glaucoma surgery
• Cataract surgery
• Uveitis
• Retinal disease
• Herpes infection
• Medication allergies
• Asthma or heart disease
• Anticoagulant use
• Pregnancy
• Current glaucoma drops

Visual-Acuity Testing

Vision is measured before treatment.

This provides a baseline for postoperative comparison.

Eye-Pressure Measurement

Eye pressure is measured and compared with:

• Previous readings
• The target pressure
• Current treatment
• Disease progression

Gonioscopy

Gonioscopy assesses:

• Whether the angle is open
• Degree of pigmentation
• Peripheral anterior synechiae
• Neovascularisation
• Plateau iris
• Suitability for SLT or LPI

Optic-Nerve Examination

The optic nerve is examined for:

• Rim thinning
• Cupping
• Disc haemorrhage
• Asymmetry
• Progression

OCT Imaging

OCT may measure:

• Retinal nerve-fibre layer
• Ganglion-cell layer
• Optic-nerve structure
• Progression over time

Visual-Field Testing

Visual-field testing helps determine:

• Severity
• Functional loss
• Rate of progression
• Required target pressure

Anterior-Segment Imaging

Anterior-segment OCT or ultrasound biomicroscopy may be useful for:

• Narrow angles
• Plateau iris
• Lens vault
• Ciliary-body anatomy
• Persistent angle closure

Preparation Before Laser

Instructions vary according to the procedure.

Patients should generally:

• Continue glaucoma drops unless told otherwise
• Bring a current medication list
• Report medication allergies
• Arrange transport when vision may be temporarily blurred
• Avoid driving immediately after pupil dilation
• Eat normally unless sedation is planned

Blood-thinning medication should not be stopped unless the prescribing doctor and ophthalmologist specifically advise it.

Recovery After SLT

The First Day

The eye may feel:

• Mildly sore
• Gritty
• Light-sensitive
• Slightly blurred

Normal activities are often possible.

Eye Drops

The patient may receive:

• A short course of anti-inflammatory drops
• No additional drops
• Temporary pressure-lowering treatment

Evidence has not shown that brief postoperative steroid or non-steroidal anti-inflammatory treatment prevents SLT’s pressure-lowering effect.

Existing Glaucoma Medication

Existing drops should usually continue until the ophthalmologist confirms that SLT has lowered pressure adequately.

Recovery After LPI

Temporary symptoms may include:

• Blurred vision
• Brow ache
• Mild light sensitivity
• Redness
• A small amount of iris bleeding
• Headache from pilocarpine

Anti-inflammatory drops are commonly prescribed for several days.

The iridotomy must later be checked for:

• Patency
• Adequate size
• Persistent angle closure
• Pressure response

Recovery After Cyclophotocoagulation

Recovery is more variable.

Possible symptoms include:

• Pain
• Redness
• Swelling
• Blurred vision
• Light sensitivity
• Inflammation

Treatment may include:

• Steroid drops
• Cycloplegic drops
• Antibiotics in selected procedures
• Oral pain medication
• Temporary pressure-lowering medication

The eye pressure may fluctuate before stabilising.

When Can I Return to Work?

After uncomplicated SLT or LPI, many patients return to ordinary activities within one or two days.

More time may be required after cyclophotocoagulation because of:

• Anaesthesia
• Inflammation
• Pain
• Blurred vision
• The severity of the underlying glaucoma

Can I Use Screens?

Yes.

Screens do not reverse laser treatment.

Temporary dryness or blur may make prolonged screen use uncomfortable.

When Can I Drive?

Driving should resume only when:

• Vision is clear enough
• The pupil is no longer significantly affected
• Glare is manageable
• Sedative effects have resolved
• The patient meets the legal visual standard

When Can I Exercise?

Light activity is usually possible after uncomplicated SLT or LPI.

More strenuous activity may need to be avoided temporarily after cyclophotocoagulation or another intraocular procedure.

Can I Fly?

Routine uncomplicated SLT and LPI do not place a gas bubble inside the eye and generally do not prevent flying.

Travel should not interfere with:

• Early pressure checks
• Post-laser review
• Access to emergency care

Can Laser Treatment Fail?

Yes.

Possible reasons include:

• The treated mechanism was not the principal cause of pressure elevation
• The trabecular meshwork did not respond
• The angle remains closed
• Scar tissue limits drainage
• The treatment effect wears off
• The disease requires a lower target pressure
• The laser dose was deliberately conservative
• Glaucoma continues progressing despite apparently acceptable pressure

How Is Success Defined?

Success may mean:

• Lower eye pressure
• Reaching the target pressure
• Fewer medications
• Avoiding surgery
• Preventing an acute angle-closure attack
• Stable optic-nerve structure
• Stable visual fields

A successful laser does not necessarily eliminate all glaucoma drops.

Common Myths

“Laser Cures Glaucoma”

False.

It controls pressure or treats an anatomical mechanism.

“Laser Restores Vision Lost from Glaucoma”

False.

Established optic-nerve loss is usually permanent.

“Laser Is Only Used After Drops Fail”

False.

SLT may be used as first-line treatment.

“SLT Burns Holes in the Drainage System”

False.

It stimulates a biological drainage response.

“SLT Works Immediately”

Not usually.

The full effect may take several weeks.

“SLT Always Eliminates Drops”

False.

Some patients remain on medication.

“Laser Can Be Repeated Indefinitely”

False.

Repeatability depends on the procedure, response and tissue condition.

“LPI Is a Pressure-Lowering Procedure for Every Glaucoma Patient”

False.

It primarily treats pupil block and angle closure.

“A Successful LPI Means the Angle Is Permanently Wide”

False.

Persistent or recurrent narrowing may occur.

“Everyone with Narrow Angles Needs an Iridotomy”

False.

The decision depends on individual risk.

“Cyclophotocoagulation Is Only for Blind Eyes”

No longer universally true.

Modern micropulse and slow-coagulation techniques may be used in selected seeing eyes.

“Micropulse Laser Has No Risks”

False.

It may have a safer complication profile than conventional continuous-wave treatment but can still cause inflammation, hypotony, vision loss or insufficient pressure reduction.

“Normal Eye Pressure Means Glaucoma Is Stable”

False.

Stability must be assessed with optic-nerve imaging and visual fields.

Frequently Asked Questions

Which Laser Is Best for Glaucoma?

The correct laser depends on the glaucoma mechanism.

• Open-angle glaucoma: usually SLT
• Pupil-block angle closure: usually LPI
• Persistent peripheral angle crowding: selected iridoplasty
• Refractory glaucoma: cyclophotocoagulation or surgery

Can SLT Be Performed in Both Eyes on the Same Day?

Yes, in selected patients.

Some ophthalmologists treat the eyes separately to:

• Assess the first-eye response
• Reduce simultaneous pressure-spike risk
• Limit bilateral inflammation

Can LPI Be Performed in Both Eyes?

Yes.

The fellow eye is commonly treated when one eye has experienced acute angle closure.

Can I Stop My Glaucoma Drops After Laser?

Only when instructed.

Stopping treatment too early may allow pressure to rise before the laser effect develops.

How Soon Should Pressure Be Checked?

The schedule depends on:

• Type of laser
• Starting pressure
• Glaucoma severity
• Angle pigmentation
• Previous pressure spikes
• Medication

Some patients require a check within hours.

Others may be reviewed after several days or weeks.

Can SLT Be Used After Cataract Surgery?

Yes.

SLT may be performed in an eye with an intraocular lens if the drainage angle is open and visible.

Can SLT Be Used After Glaucoma Surgery?

Possibly.

It may be considered when sufficient functional trabecular meshwork remains visible.

Can SLT Be Used in Angle-Closure Glaucoma?

Sometimes, after LPI or lens extraction has opened enough of the angle to expose the trabecular meshwork.

Recent evidence suggests that SLT can lower pressure in selected primary angle-closure glaucoma eyes with visible trabecular meshwork, but it is not a substitute for treating the underlying angle closure.

Can LPI Close?

Yes.

A small opening may close because of:

• Pigment
• Inflammation
• Iris tissue
• Incomplete penetration

Repeat laser may be required.

Does LPI Cause Cataract?

LPI does not automatically cause a cataract.

The natural lens may already be crowded or ageing in eyes with narrow angles.

Direct laser injury to the lens is uncommon but possible.

Can Laser Cause Blindness?

Severe permanent visual loss is rare after SLT or LPI.

The risk is greater with more destructive procedures such as conventional cyclophotocoagulation, particularly in advanced or surgically complex eyes.

Can Glaucoma Continue Progressing After Successful Laser?

Yes.

The ophthalmologist may need to:

• Lower the target pressure further
• Repeat laser
• Add medication
• Perform surgery
• Investigate pressure-independent factors

How Often Must I Be Reviewed?

Review frequency depends on:

• Glaucoma severity
• Pressure
• Laser response
• Visual-field progression
• Optic-nerve findings
• The procedure performed

Glaucoma remains a lifelong condition even when pressure is well controlled.

When to Seek Urgent Eye Care

Seek urgent assessment for:

• Severe eye pain
• Rapidly worsening vision
• Increasing redness
• Severe headache
• Nausea or vomiting
• Marked halos associated with pain
• Significant light sensitivity
• Thick discharge
• A white corneal spot
• New flashes or floaters
• A curtain or shadow
• Sudden loss of previously clear vision

After laser treatment, these symptoms may indicate:

• A significant eye-pressure spike
• Acute inflammation
• Infection
• Corneal injury
• Angle closure
• Retinal disease
• Another ocular emergency

A Laser Glaucoma Treatment Checklist

Information to Report

• Current glaucoma drops
• Medication allergies
• Asthma
• Heart rhythm or blood-pressure problems
• Previous eye-pressure spikes
• Previous laser treatment
• Previous glaucoma surgery
• Uveitis
• Retinal disease
• Cataract surgery
• Blood-thinning medication

Tests That May Be Required

• Visual acuity
• Eye-pressure measurement
• Gonioscopy
• Optic-nerve examination
• OCT imaging
• Visual-field testing
• Corneal thickness measurement
• Anterior-segment OCT
• Ultrasound biomicroscopy
• Dilated retinal examination

Questions to Ask the Ophthalmologist

• What type of glaucoma do I have?
• What is my target eye pressure?
• Which laser procedure is being recommended?
• What structure will the laser treat?
• Is laser the first treatment or an additional treatment?
• How likely is the procedure to lower my pressure?
• Could I reduce or stop any drops?
• How long should the effect last?
• Can the procedure be repeated?
• What are the alternatives?
• What is my risk of a pressure spike?
• When will my pressure be checked?
• Should I continue my existing drops?
• What symptoms require urgent review?
• How will we determine whether the laser worked?
• How often will I need OCT and visual-field testing?

The Bottom Line

Laser glaucoma treatment includes several different procedures.

The main options are:

• Selective laser trabeculoplasty for open-angle glaucoma
• Laser peripheral iridotomy for pupil-block angle closure
• Laser peripheral iridoplasty for selected persistent angle crowding
• Cyclophotocoagulation for refractory or advanced glaucoma
• Endoscopic cyclophotocoagulation as an intraocular treatment, sometimes combined with cataract surgery

SLT improves drainage through the trabecular meshwork.

It may be used:

• As first-line treatment
• Instead of drops
• Together with drops
• As repeat treatment in selected patients

LPI creates an opening in the peripheral iris.

It reduces pupil block but may not completely open an angle narrowed by:

• Plateau iris
• A large natural lens
• Peripheral anterior synechiae
• Other anatomical factors

Cyclophotocoagulation reduces aqueous-fluid production.

Modern micropulse techniques may have fewer serious complications than conventional continuous-wave treatment, although repeat treatment or additional medication may still be needed.

Possible benefits of glaucoma laser include:

• Lower eye pressure
• Reduced medication burden
• Delayed surgery
• Prevention of acute angle closure
• Preservation of remaining vision

Possible risks include:

• Temporary pressure elevation
• Inflammation
• Pain
• Bleeding
• Glare or dysphotopsia
• Corneal injury
• Failure to lower pressure
• Hypotony or vision loss after cyclophotocoagulation
• Need for repeat treatment or surgery

The most important message is:

Laser treatment can be highly effective, but the correct procedure must match the glaucoma mechanism. Successful pressure lowering does not reverse existing optic-nerve damage or remove the need for lifelong monitoring with eye-pressure measurements, optic-nerve imaging and visual-field testing.

References

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