Diabetic Retinopathy: Symptoms, Stages, Screening and Treatment

Author: Dr Val Phua
Estimated reading time: 20 minutes

Diabetic retinopathy is a complication of diabetes that damages the small blood vessels of the retina—the light-sensitive tissue lining the inside of the back of the eye.

It can occur in people with:

• Type 1 diabetes
• Type 2 diabetes
• Other forms of long-standing diabetes

Diabetic retinopathy is particularly dangerous because the early and intermediate stages often cause no symptoms. A person may have clear vision and still have significant retinal changes requiring closer monitoring.

As the condition progresses, it can cause:

• Diabetic macular oedema
• Bleeding inside the eye
• Abnormal retinal blood-vessel growth
• Scar-tissue formation
• Tractional retinal detachment
• Glaucoma
• Permanent loss of vision

A global analysis estimated that approximately one in five people with diabetes had some degree of diabetic retinopathy, with the number affected expected to increase substantially as the worldwide prevalence of diabetes rises.

The encouraging news is that most severe visual loss from diabetic retinopathy can be prevented through:

• Regular retinal screening
• Appropriate blood-glucose management
• Blood-pressure control
• Management of cholesterol and kidney disease
• Timely anti-VEGF injections
• Laser treatment
• Vitreoretinal surgery when required

The purpose of screening is to identify retinal changes before the patient notices vision loss. The 2026 American Diabetes Association Standards and the American Academy of Ophthalmology guidelines continue to emphasise regular, validated retinal screening and prompt referral when retinopathy is detected.

The Quick Answer

What Is Diabetic Retinopathy?

Diabetic retinopathy develops when prolonged exposure to high blood glucose and other metabolic factors damages the retinal circulation.

The retinal blood vessels may:

• Become abnormally permeable
• Leak fluid or blood
• Develop small outpouchings
• Become blocked
• Reduce oxygen supply to retinal tissue
• Produce abnormal new blood vessels

These changes may affect peripheral retinal circulation, the central macula or both.

Does Diabetic Retinopathy Cause Symptoms?

Not necessarily.

Early diabetic retinopathy usually causes no symptoms. Sight may remain normal even when retinal photographs show multiple haemorrhages, microaneurysms or vascular abnormalities.

When symptoms occur, they may include:

• Blurred vision
• Fluctuating vision
• Distorted vision
• Difficulty reading
• Reduced contrast
• Colours appearing dull
• Floaters
• Cobwebs
• Dark spots
• A sudden haze
• A curtain or missing area of vision

Can Diabetic Retinopathy Cause Blindness?

Yes.

Severe visual loss can result from:

• Diabetic macular oedema
• Vitreous haemorrhage
• Tractional retinal detachment
• Macular ischaemia
• Neovascular glaucoma
• Permanent retinal scarring

However, regular screening and timely treatment greatly reduce the risk of reaching these stages.

Can Diabetic Retinopathy Be Cured?

There is no single treatment that permanently removes the underlying diabetic tendency.

Treatment may:

• Reduce retinal leakage
• Improve macular swelling
• Cause abnormal vessels to regress
• Reduce the risk of bleeding
• Prevent retinal detachment
• Stabilise or improve vision

Continued control of diabetes and lifelong retinal monitoring are still required.

Is Diabetic Retinopathy an Emergency?

Early diabetic retinopathy is not usually an emergency.

Arrange urgent same-day assessment if you develop:

• A sudden shower of floaters
• New cobwebs or dark spots
• Sudden blurred or hazy vision
• A large red or black area in the vision
• A curtain or shadow
• Sudden loss of central or peripheral vision
• Eye pain with redness and blurred vision

These symptoms may indicate vitreous haemorrhage, retinal detachment or neovascular glaucoma.

Understanding the Retina and Macula

The Retina

The retina is a thin layer of specialised nerve tissue at the back of the eye.

It converts light into electrical signals that travel through the optic nerve to the brain.

For normal vision, the retina requires:

• A healthy blood supply
• Transparent retinal tissue
• A clear vitreous cavity
• An attached retinal surface
• Normal communication with the optic nerve

The Macula

The macula is the central portion of the retina.

It is responsible for:

• Reading
• Recognising faces
• Driving
• Colour perception
• Fine detail
• Central visual clarity

The centre of the macula is called the fovea.

Fluid affecting the macula can impair vision even when the rest of the retina remains attached.

The Retinal Blood Vessels

The retina has a fine network of arteries, veins and capillaries.

Diabetes can damage:

• Endothelial cells lining the vessels
• Supporting pericyte cells
• The blood-retinal barrier
• Capillary circulation
• Retinal nerve cells

This produces a combination of leakage and inadequate blood supply.

How Does Diabetes Damage the Retina?

Chronic High Blood Glucose

Long-term exposure to elevated blood glucose produces biochemical and structural changes within retinal vessels.

The risk generally increases with:

• Longer duration of diabetes
• Higher average glucose exposure
• Greater variation in glucose
• Coexisting hypertension
• Kidney disease
• Abnormal blood lipids

Landmark randomised trials demonstrated that improved glycaemic control reduces the development and progression of microvascular complications in both type 1 and type 2 diabetes.

Breakdown of the Blood-Retinal Barrier

Healthy retinal capillaries regulate which substances leave the circulation.

When the barrier is damaged, vessels may leak:

• Plasma
• Lipoproteins
• Fluid
• Blood cells

This can produce:

• Retinal swelling
• Hard exudates
• Diabetic macular oedema
• Reduced visual function

Capillary Closure

Damaged capillaries may become blocked.

The affected retina then receives less oxygen.

The eye responds by producing signalling molecules, including vascular endothelial growth factor, or VEGF.

Abnormal New Blood Vessels

High VEGF levels can stimulate fragile new vessels to grow on:

• The optic disc
• The retinal surface
• The iris
• The drainage structures at the front of the eye

These vessels are abnormal and may:

• Bleed easily
• Form scar tissue
• Pull on the retina
• Block the drainage of fluid from the eye

The Main Forms of Diabetic Retinopathy

Non-Proliferative Diabetic Retinopathy

Non-proliferative diabetic retinopathy, or NPDR, is the earlier stage.

The word “non-proliferative” means that abnormal new vessels have not yet developed.

NPDR may be classified as:

• Mild
• Moderate
• Severe

Proliferative Diabetic Retinopathy

Proliferative diabetic retinopathy, or PDR, is the advanced stage in which abnormal new vessels grow because of retinal oxygen deprivation.

These vessels can lead to:

• Vitreous haemorrhage
• Fibrous scar tissue
• Tractional retinal detachment
• Neovascular glaucoma

Diabetic Macular Oedema

Diabetic macular oedema, or DME, refers to retinal thickening caused by leakage in or near the macula.

DME can occur:

• With mild NPDR
• With moderate or severe NPDR
• With PDR
• In one eye or both eyes

It is not a separate stage of retinopathy and may be present at any severity level.

Mild Non-Proliferative Diabetic Retinopathy

Microaneurysms

The earliest visible changes are often microaneurysms.

These are tiny outpouchings of damaged retinal capillaries.

They may appear as small red dots on retinal examination or photography.

Vision Is Usually Normal

Mild NPDR commonly causes no symptoms unless macular oedema is also present.

Treatment generally focuses on:

• Diabetes management
• Blood-pressure control
• Appropriate follow-up
• Monitoring for progression

Moderate Non-Proliferative Diabetic Retinopathy

Increasing Vascular Damage

Moderate NPDR may include:

• More retinal haemorrhages
• Microaneurysms
• Hard exudates
• Cotton-wool spots
• Venous changes
• Early intraretinal microvascular abnormalities

The severity can vary considerably within this category.

Closer Follow-Up May Be Needed

The monitoring interval depends on:

• The extent of retinal changes
• Presence of DME
• Glucose and blood-pressure control
• Pregnancy
• Kidney disease
• Previous rate of progression

Severe Non-Proliferative Diabetic Retinopathy

Significant Retinal Ischaemia

Severe NPDR indicates extensive retinal vascular damage and a higher risk of progression to PDR.

Ophthalmologists may use the 4-2-1 rule, which considers:

• Extensive haemorrhages or microaneurysms in all four retinal quadrants
• Venous beading in at least two quadrants
• Prominent intraretinal microvascular abnormalities in at least one quadrant

The presence of one or more of these findings helps classify severe disease.

Treatment May Be Considered Before PDR Develops

Management depends on:

• Follow-up reliability
• Whether one or both eyes are affected
• Pregnancy plans
• Cataract or other upcoming surgery
• Macular oedema
• The condition of the fellow eye
• Access to emergency care

Selected patients may be considered for laser or injection treatment before the disease progresses further.

Proliferative Diabetic Retinopathy

What Does Proliferative Mean?

“Proliferative” refers to the growth of abnormal new retinal blood vessels.

These vessels develop in response to severe retinal ischaemia.

The New Vessels Are Fragile

Unlike normal mature vessels, the abnormal vessels:

• Lack stable supporting structures
• Leak easily
• Bleed into the vitreous
• Grow with fibrous tissue
• Contract over time

PDR May Be Asymptomatic

A patient can have PDR and still see well if:

• The macula remains dry
• No major bleeding has occurred
• The scar tissue has not pulled on the central retina

This is why screening remains essential even when vision is clear.

Diabetic Macular Oedema

What Is Diabetic Macular Oedema?

DME occurs when damaged retinal vessels leak fluid into the macula.

OCT may show:

• Retinal thickening
• Intraretinal cysts
• Subretinal fluid
• Hard exudates
• Altered foveal contour

Centre-Involving and Non-Centre-Involving DME

DME may be classified according to whether swelling involves the central fovea.

Centre-involving DME affects the retinal centre and is more likely to reduce detailed vision.

Non-centre-involving DME affects areas near, but not directly within, the central fovea.

Symptoms of DME

DME may cause:

• Blurred central vision
• Difficulty reading
• Distortion
• Reduced contrast
• Colours appearing washed out
• Unequal image size between the eyes
• Fluctuating vision

The symptoms may develop gradually.

DME With Good Vision

OCT-detected centre-involving DME does not always require immediate injection if visual acuity remains good.

In DRCR Retina Network Protocol V, initial aflibercept, laser or observation produced similar two-year visual outcomes when treatment was added if vision worsened. Carefully monitored observation may therefore be reasonable for selected eyes with centre-involving DME and good visual acuity.

Observation is an active management strategy requiring scheduled follow-up—not permission to ignore the condition.

Diabetic Macular Ischaemia

What Is Macular Ischaemia?

Macular ischaemia occurs when the fine capillary network supplying the macula becomes significantly reduced or closed.

It may cause:

• Blurred vision
• Reduced contrast
• Poor reading vision
• Visual loss out of proportion to retinal swelling

Can Injections Restore the Circulation?

Anti-VEGF injections can treat leakage and neovascularisation but cannot reliably recreate capillaries that have already closed.

Vision may therefore remain limited even when OCT swelling improves.

Symptoms of Diabetic Retinopathy

No Symptoms

The most common early presentation is no visual complaint at all.

A normal spectacle prescription or clear distance vision does not exclude diabetic retinopathy.

Blurred Vision

Blur may be caused by:

• Diabetic macular oedema
• Macular ischaemia
• Vitreous haemorrhage
• Cataract
• Fluctuating blood glucose
• Corneal or ocular-surface disease

Fluctuating Vision

Rapid changes in blood glucose can temporarily alter the focusing power of the natural lens.

Vision may change:

• From day to day
• Between morning and evening
• During periods of unstable glucose

A glasses prescription should ideally be measured when blood glucose is reasonably stable.

Distorted Vision

Straight lines may appear:

• Bent
• Wavy
• Broken
• Uneven

This may indicate macular swelling or another macular condition.

Floaters and Cobwebs

Vitreous haemorrhage may be perceived as:

• Small black dots
• Threads
• Cobwebs
• Red clouds
• A smoky haze
• A large dark area

The severity depends on the amount and location of bleeding.

Sudden Visual Loss

Sudden visual loss may occur with:

• Dense vitreous haemorrhage
• Tractional retinal detachment
• Combined retinal detachment
• Retinal vascular occlusion
• Acute neovascular glaucoma

Urgent examination is required.

A Curtain or Missing Visual Field

A dark curtain or missing area may indicate retinal detachment.

This is an emergency.

Eye Pain

Diabetic retinopathy itself is usually painless.

Pain, redness, headache, nausea and blurred vision may indicate:

• Neovascular glaucoma
• Corneal disease
• Infection
• Another acute eye condition

Does Diabetic Retinopathy Affect Both Eyes?

Diabetic retinopathy commonly affects both eyes because diabetes is a systemic condition.

However, the severity may differ because of:

• Unequal retinal circulation
• Previous retinal vascular occlusion
• Carotid-artery disease
• Previous laser or injections
• Different ocular anatomy
• Previous surgery
• Local retinal factors

Marked asymmetry may prompt investigation for another circulatory or ocular condition.

Risk Factors

Duration of Diabetes

The longer a person has diabetes, the greater the cumulative risk of retinal damage.

Retinopathy may already be present when type 2 diabetes is first diagnosed because high glucose may have existed unnoticed for years. This is why retinal examination is recommended at the time of diagnosis of type 2 diabetes.

Blood-Glucose Control

Higher long-term glucose exposure is strongly associated with development and progression of retinopathy.

Improved control reduces risk, but glucose targets should be individualised to avoid severe hypoglycaemia and other complications.

High Blood Pressure

Hypertension places additional stress on damaged retinal vessels.

The UK Prospective Diabetes Study demonstrated that improved blood-pressure control reduced microvascular complications in people with type 2 diabetes and hypertension.

Abnormal Blood Lipids

Raised cholesterol and triglycerides may be associated with:

• Hard exudates
• Retinal leakage
• Cardiovascular risk
• Retinopathy progression

In the ACCORD Eye study, intensive glycaemic treatment and fenofibrate added to statin therapy reduced retinopathy progression in selected participants with type 2 diabetes, although medication decisions must consider the patient’s wider cardiovascular, kidney and metabolic health.

Kidney Disease

Diabetic kidney disease often indicates broader microvascular damage.

Patients with:

• Protein in the urine
• Reduced kidney function
• Dialysis requirements

may have a greater risk of severe retinopathy.

Pregnancy

Pregnancy may accelerate existing diabetic retinopathy, particularly when:

• Retinopathy is already present
• Glucose control changes rapidly
• Hypertension or pre-eclampsia develops
• Diabetes has been present for many years

Patients with pre-existing type 1 or type 2 diabetes should receive retinal assessment before pregnancy when possible and early in pregnancy, with follow-up based on the severity of retinal disease.

Smoking

Smoking increases cardiovascular and vascular risk and should be stopped.

Anaemia and Sleep Apnoea

Anaemia and obstructive sleep apnoea may worsen tissue oxygenation and should be assessed and managed when clinically relevant.

Puberty and Young-Onset Diabetes

Rapid growth, hormonal changes and longer lifetime exposure make regular screening particularly important in children and young adults with diabetes.

Can Rapid Improvement in Blood Glucose Worsen Retinopathy?

Early Worsening Can Occur

A large and rapid improvement in glucose may sometimes cause a temporary worsening of pre-existing retinopathy.

This phenomenon was recognised in landmark intensive-control studies.

It does not mean that good glucose control is harmful overall. Long-term control remains protective.

Monitoring Should Be Coordinated

Patients with:

• Severe NPDR
• PDR
• Significant DME
• Pregnancy
• Very high HbA1c before treatment intensification

may require retinal assessment before or soon after major changes in diabetic treatment.

Do not deliberately keep glucose high to protect the eyes. Coordinate the rate of improvement and retinal follow-up with the diabetes and eye-care teams.

Screening Recommendations

Type 1 Diabetes in Adults

Adults with type 1 diabetes should generally have an initial dilated and comprehensive retinal examination within five years after the onset of diabetes.

Earlier examination may be appropriate when:

• The date of onset is uncertain
• Visual symptoms are present
• Pregnancy is planned
• Another eye condition exists
• The clinician has a specific concern

Type 2 Diabetes in Adults

A dilated comprehensive retinal examination is recommended at the time type 2 diabetes is diagnosed because retinopathy may already be present.

Follow-Up When No Retinopathy Is Present

If repeated annual examinations show no retinopathy and glucose indicators remain within the individual target range, screening every one to two years may be considered.

The interval should remain individualised according to:

• Diabetes duration
• Glucose control
• Blood pressure
• Kidney disease
• Previous retinal findings
• Pregnancy
• Access to care

Follow-Up When Retinopathy Is Present

When retinopathy is detected, examinations should generally occur at least annually and more frequently when the disease is:

• Moderate or severe
• Progressing
• Associated with DME
• Proliferative
• Being actively treated
• Present during pregnancy

Children With Type 1 Diabetes

Pediatric screening schedules depend on:

• Age
• Pubertal status
• Duration of diabetes
• Existing retinopathy
• Current guideline recommendations

The diabetes and eye-care teams should establish an individual screening schedule.

Children With Type 2 Diabetes

Because young people with type 2 diabetes may already have a period of unrecognised hyperglycaemia, retinal screening commonly begins at or soon after diagnosis.

Pregnancy

Patients with pre-existing type 1 or type 2 diabetes should ideally be examined:

• Before conception
• During the first trimester
• During later trimesters as indicated
• For up to one year postpartum according to retinopathy severity

Pregnancy-related screening recommendations do not apply in the same way to gestational diabetes developing during pregnancy without pre-existing diabetes.

Retinal Photography and Artificial Intelligence Screening

Retinal Photography

Retinal cameras can document:

• Microaneurysms
• Haemorrhages
• Exudates
• Venous changes
• New vessels
• Previous laser scars

Validated photography programmes can improve access to screening.

Artificial Intelligence Assessment

Validated automated systems may analyse retinal images for referable diabetic retinopathy.

These systems can be useful in:

• Primary-care clinics
• Diabetes centres
• Community screening programmes
• Areas with limited specialist access

Screening Is Not a Complete Eye Examination

A retinal photograph may not adequately assess:

• Eye pressure
• Cataracts
• The peripheral retina
• The optic nerve
• Corneal disease
• Every cause of visual symptoms

An ungradable image or abnormal screening result requires referral for a proper eye examination.

How Is Diabetic Retinopathy Diagnosed?

Visual-Acuity Testing

Visual acuity measures central high-contrast vision.

Good visual acuity does not exclude retinopathy.

Dilated Retinal Examination

Dilating drops enlarge the pupil so the ophthalmologist can examine:

• The optic disc
• Macula
• Retinal vessels
• Peripheral retina
• Vitreous

Fundus Photography

Photographs help:

• Document severity
• Compare changes
• Support grading
• Monitor treatment
• Improve patient education

Optical Coherence Tomography

OCT produces detailed cross-sectional images of the macula.

It can detect:

• Retinal thickening
• Intraretinal cysts
• Subretinal fluid
• Vitreomacular traction
• Epiretinal membrane
• Retinal tissue loss
• Treatment response

OCT has become central to the diagnosis and monitoring of DME.

Fluorescein Angiography

A fluorescent dye is injected into a vein and photographed as it travels through the retinal circulation.

The test may demonstrate:

• Areas of leakage
• Capillary closure
• Macular ischaemia
• New vessels
• Sources of focal leakage

OCT Angiography

OCT angiography provides non-invasive images of retinal blood flow.

It may show:

• Capillary dropout
• Enlargement of the foveal avascular zone
• Abnormal vascular networks
• Retinal ischaemia

It does not fully replace fluorescein angiography because it does not directly display leakage.

Ultrasound

When blood or cataract prevents the retina from being seen, ultrasound can assess for:

• Retinal detachment
• Traction
• Vitreous membranes
• Intraocular masses

Treatment Goals

Treatment aims to:

• Preserve useful vision
• Reduce macular swelling
• Cause abnormal vessels to regress
• Prevent vitreous haemorrhage
• Prevent or repair retinal detachment
• Reduce the risk of neovascular glaucoma
• Minimise treatment burden
• Maintain the patient’s independence

The correct treatment depends on whether the main problem is:

• NPDR
• DME
• PDR
• Vitreous haemorrhage
• Tractional retinal detachment
• A combination of these

Systemic Diabetes Management

Blood-Glucose Control

Good long-term control reduces the risk of developing and worsening retinopathy.

Targets should be set with the diabetes team according to:

• Age
• Type and duration of diabetes
• Cardiovascular disease
• Hypoglycaemia risk
• Kidney function
• Pregnancy
• Other health conditions

Blood-Pressure Control

Treating hypertension protects:

• Eyes
• Kidneys
• Heart
• Brain

Cholesterol Management

Management may include:

• Dietary changes
• Exercise
• Statins
• Other lipid-lowering medication
• Fenofibrate in selected patients

Medication decisions should be made by the treating physician.

Kidney and Anaemia Management

Retinal disease may be more difficult to control when severe kidney disease or anaemia remains untreated.

Stop Smoking

Smoking cessation supports general vascular health and reduces cardiovascular risk.

Observation

When Is Observation Appropriate?

Observation may be appropriate for:

• Mild NPDR
• Selected moderate NPDR
• DME that does not involve the centre
• Centre-involving DME with good visual acuity
• Stable disease after treatment

Observation requires:

• Scheduled examinations
• OCT when indicated
• Retinal photographs
• Good systemic control
• Immediate reporting of new symptoms

Observation Does Not Mean the Disease Is Harmless

The purpose is to avoid unnecessary treatment while maintaining a safe opportunity to intervene if the condition worsens.

Anti-VEGF Injections for Diabetic Macular Oedema

What Is VEGF?

VEGF is a signalling protein that increases:

• Blood-vessel permeability
• Retinal leakage
• Abnormal new-vessel growth

How Do Anti-VEGF Injections Work?

Anti-VEGF medication is injected into the vitreous cavity.

It may:

• Reduce macular leakage
• Reduce retinal thickness
• Improve vision
• Stabilise vision
• Improve retinopathy severity
• Cause abnormal vessels to regress

Which Medicines Are Used?

Depending on local approval, availability and clinical circumstances, treatment may include:

• Aflibercept
• Ranibizumab
• Bevacizumab
• Faricimab
• Higher-dose aflibercept formulations

Bevacizumab is used off-label for ocular treatment in many healthcare systems.

Is One Injection Enough?

Usually not.

Treatment often begins with repeated injections separated by several weeks.

The interval may later be extended according to:

• OCT appearance
• Visual acuity
• Retinal fluid
• Previous response
• The medication used
• The treatment protocol

Are All Anti-VEGF Medicines Equal?

All commonly used anti-VEGF medicines can improve vision in centre-involving DME with visual impairment.

In Protocol T, the average difference between aflibercept, bevacizumab and ranibizumab depended partly on baseline vision. When initial visual loss was mild, average outcomes were similar; when starting vision was worse, aflibercept produced greater average improvement at one year.

The most appropriate drug depends on:

• Baseline vision
• Previous response
• Cost and funding
• Availability
• Injection interval
• Systemic and ocular history
• Physician judgement

Newer Extended-Interval Treatments

Phase 3 trials have shown that faricimab and aflibercept 8 mg can maintain visual gains in many patients using extended treatment intervals after an initial loading phase. These treatments may reduce injection burden for selected patients, although individual response and local regulatory approval vary.

What Happens During an Eye Injection?

Before the Injection

The clinic may:

• Check vision
• Measure eye pressure
• Perform OCT
• Confirm the eye and medication
• Apply anaesthetic drops
• Clean the eyelids and eye with antiseptic

During the Injection

A small instrument keeps the eyelids open.

The medication is injected through the white part of the eye.

The injection itself is usually brief.

After the Injection

Temporary symptoms may include:

• Grittiness
• Watering
• A small red patch
• A moving bubble
• Mild floaters
• Brief blurred vision

Warning Signs After an Injection

Seek urgent assessment for:

• Increasing pain
• Increasing redness
• Marked light sensitivity
• Worsening vision
• Thick discharge
• Increasing eyelid swelling

These may indicate endophthalmitis or another serious complication.

Steroid Treatment for Diabetic Macular Oedema

Why Are Steroids Used?

Inflammation contributes to retinal leakage in DME.

Intravitreal corticosteroids may reduce:

• Inflammation
• Vascular permeability
• Macular swelling

Types of Steroid Treatment

Treatment may include:

• Dexamethasone implant
• Fluocinolone acetonide implant
• Other intravitreal steroid preparations

When May Steroids Be Considered?

Steroids may be considered when:

• DME responds incompletely to anti-VEGF treatment
• Injection frequency is difficult to sustain
• The eye has undergone vitrectomy
• The patient is already pseudophakic
• Anti-VEGF treatment is unsuitable
• There is a strong inflammatory component

Risks

Steroid treatment can cause:

• Raised eye pressure
• Glaucoma
• Cataract progression
• Need for pressure-lowering medication
• Need for glaucoma surgery
• Infection related to injection

The MEAD trials demonstrated visual and anatomical benefits from dexamethasone implants but also confirmed substantial rates of cataract and pressure elevation.

Laser Treatment for Diabetic Macular Oedema

Focal or Grid Laser

Macular laser treatment applies small burns to areas of retinal leakage or thickening.

It may be considered for:

• Selected non-centre-involving DME
• Focal leakage away from the fovea
• DME requiring additional treatment
• Situations in which injections are unsuitable

Laser Is No Longer the First Treatment for Most Vision-Impairing Centre-Involving DME

Anti-VEGF therapy generally provides better visual outcomes for centre-involving DME with reduced vision.

Laser remains useful in selected patterns and as an adjunct.

Possible Laser Effects

Patients may notice:

• Small blind spots
• Reduced contrast
• Temporary blur
• Difficulty adapting immediately after treatment

Careful modern laser aims to minimise damage to central vision.

Treatment of Proliferative Diabetic Retinopathy

Panretinal Photocoagulation

Panretinal photocoagulation, or PRP, places multiple laser spots in the peripheral retina.

The laser reduces the stimulus driving abnormal vessel growth.

PRP aims to:

• Cause abnormal vessels to regress
• Reduce future bleeding
• Reduce the risk of severe visual loss
• Reduce the risk of neovascular glaucoma

Anti-VEGF Injections

Anti-VEGF injections can also cause abnormal vessels to regress.

They may be particularly useful when PDR occurs with DME.

PRP Versus Anti-VEGF

DRCR Protocol S found that both PRP and ranibizumab were viable treatments for PDR.

At five years:

• Average visual acuity was similar.
• Severe visual loss was uncommon with either strategy.
• Ranibizumab-treated eyes had less visual-field loss and a lower rate of vision-impairing DME.
• Injection treatment required substantially more visits and repeated injections.

Why Follow-Up Reliability Matters

Anti-VEGF suppression is temporary.

If injections are stopped and follow-up is lost:

• New vessels may reactivate.
• Bleeding may occur.
• Scar tissue may progress.
• Retinal detachment may develop.

PRP may provide a more durable strategy for patients who may have difficulty attending frequent appointments.

Combined Treatment

Some patients receive both:

• Anti-VEGF injections
• PRP laser

This may provide rapid regression from injections with longer-term stability from laser.

What Is PRP Treatment Like?

Before Treatment

The pupil is dilated, and anaesthetic drops are applied.

A contact lens may be placed on the eye.

During Treatment

The patient may see:

• Bright flashes
• Coloured lights
• After-images

Some patients feel:

• Mild discomfort
• Pricking
• Aching
• Pressure

Treatment may be divided over more than one session.

After Treatment

Temporary symptoms may include:

• Blurred vision
• Light sensitivity
• Headache
• Reduced night vision
• Coloured spots
• Eye ache

Possible Trade-Offs

PRP may affect:

• Peripheral visual field
• Night vision
• Dark adaptation
• Contrast
• Macular swelling

The purpose is to accept some peripheral retinal damage to prevent severe central visual loss from uncontrolled PDR.

Vitreous Haemorrhage

What Is Vitreous Haemorrhage?

The vitreous is the clear gel filling the centre of the eye.

Fragile new vessels may bleed into this gel.

Symptoms

A bleed may produce:

• A few new floaters
• Numerous black dots
• Cobwebs
• A red haze
• A dark cloud
• Sudden major loss of vision

Does the Blood Clear?

Some haemorrhages gradually clear.

The rate depends on:

• Amount of blood
• Continued bleeding
• Age and vitreous consistency
• Previous vitrectomy
• Underlying traction

Initial Treatment Options

Management may include:

• Anti-VEGF injection
• PRP when the retina can be seen
• Observation in selected cases
• Vitrectomy

In DRCR Protocol AB, both initial aflibercept and vitrectomy with PRP were viable approaches for vitreous haemorrhage from PDR, with different advantages in speed of visual recovery, treatment burden and later procedures.

Vitrectomy Surgery

What Is Vitrectomy?

Vitrectomy is an operation that removes the vitreous gel and blood from inside the eye.

The surgeon may also:

• Remove scar tissue
• Relieve traction
• Repair retinal detachment
• Apply endolaser
• Insert gas or silicone oil

When May Surgery Be Needed?

Vitrectomy may be considered for:

• Non-clearing vitreous haemorrhage
• Recurrent dense haemorrhage
• Tractional retinal detachment involving or threatening the macula
• Combined tractional and rhegmatogenous retinal detachment
• Severe fibrous proliferation
• DME associated with significant vitreomacular traction
• Neovascular complications requiring surgical management

Recovery

Recovery depends on:

• The retinal condition
• Whether gas or silicone oil is used
• Whether the macula was detached
• Duration of retinal damage
• Cataract status
• Postoperative complications

Clearing the blood does not guarantee normal vision if the macula has already been damaged by ischaemia, swelling or detachment.

Tractional Retinal Detachment

How Does It Develop?

Fibrous tissue grows together with abnormal vessels.

As this tissue contracts, it pulls the retina away from the wall of the eye.

Symptoms

A tractional detachment may cause:

• Progressive blur
• Distortion
• A missing visual field
• A dark shadow
• Sudden deterioration if a retinal tear develops

When Is Surgery Required?

Surgery is generally considered when traction:

• Involves the macula
• Threatens the macula
• Produces progressive visual loss
• Is combined with a retinal tear
• Causes recurrent bleeding

Neovascular Glaucoma

How Does It Occur?

Severe retinal ischaemia may cause abnormal vessels to grow over:

• The iris
• The drainage angle

These vessels and accompanying scar tissue can block fluid drainage.

Symptoms

Neovascular glaucoma may cause:

• Eye pain
• Redness
• Headache
• Nausea
• Halos
• Sudden blurred vision
• A hard or tender eye

Treatment

Treatment may involve:

• Anti-VEGF injection
• PRP
• Eye-pressure medication
• Glaucoma laser
• Glaucoma surgery
• Treatment of the retinal ischaemia

This requires urgent specialist care.

Diabetic Retinopathy During Pregnancy

Pregnancy Can Accelerate Disease

Patients with pre-existing diabetes may experience progression during pregnancy.

Risk is greater with:

• Existing severe retinopathy
• Long diabetes duration
• Poor previous control
• Rapid glucose improvement
• Hypertension
• Pre-eclampsia
• Kidney disease

Screening Should Begin Early

Retinal assessment should ideally occur before conception or in the first trimester, followed by monitoring based on severity and continuing postpartum when indicated.

Treatment Is Individualised

PRP remains an important treatment for PDR during pregnancy.

The use of anti-VEGF injections requires careful discussion because of limited pregnancy safety data and possible systemic effects on vascular development.

Treatment decisions should involve:

• The retinal specialist
• Obstetrician
• Endocrinologist or diabetes physician
• The patient

Diabetic Retinopathy in Children and Young Adults

Early Disease Is Possible

Retinopathy is less common soon after the onset of type 1 diabetes, but risk rises with duration and puberty.

Young people with type 2 diabetes may develop complications earlier because the disease may be aggressive and diagnosis delayed.

Vision May Remain Normal

Children should not be screened only when they report symptoms.

Family Support Matters

Parents and caregivers can help by ensuring:

• Eye appointments are attended
• Glucose monitoring is maintained
• Blood pressure is checked
• Medication is taken correctly
• New visual symptoms are reported

Cataract Surgery and Diabetic Retinopathy

Diabetes Increases Cataract Risk

People with diabetes may develop cataracts:

• At a younger age
• More rapidly
• Alongside retinopathy or DME

Retinal Assessment Is Important Before Surgery

Preoperative assessment may include:

• Dilated retinal examination
• Macular OCT
• Retinal photography
• Treatment of active DME or PDR

Surgery May Worsen Macular Oedema

Cataract surgery can increase postoperative retinal inflammation.

Patients with existing DME may have a greater risk of worsening swelling.

Should Retinopathy Be Treated First?

When possible, significant PDR or DME is commonly stabilised before elective cataract surgery.

However, a dense cataract may prevent retinal treatment or examination, making combined or staged management necessary.

Which Intraocular Lens Is Suitable?

Lens selection should consider:

• Macular function
• Retinopathy severity
• Need for future retinal treatment
• Contrast sensitivity
• Astigmatism
• Visual potential

A monofocal or toric monofocal lens is commonly preferred when significant retinal disease is present.

Can Diabetic Retinopathy Be Prevented?

It cannot always be prevented completely.

Risk can be reduced through:

• Early diagnosis of diabetes
• Individualised glucose control
• Blood-pressure management
• Cholesterol management
• Kidney-disease treatment
• Smoking cessation
• Regular exercise
• Appropriate diet
• Attendance at retinal screening
• Prompt treatment when disease becomes sight-threatening

The strongest preventive strategy is the combination of systemic risk-factor control and regular retinal surveillance.

Common Myths

“My Vision Is Clear, So My Retina Must Be Normal”

False.

Early and even proliferative retinopathy may be present without symptoms.

“I Only Need an Eye Check When My Glasses Change”

False.

A refraction does not replace a retinal examination.

“Diabetic Retinopathy Only Occurs in Type 1 Diabetes”

False.

It affects both type 1 and type 2 diabetes.

“Eye Injections Cure Diabetes”

False.

Injections treat retinal leakage or abnormal vessels. They do not treat the underlying diabetes.

“One Injection Is Usually Enough”

False.

Many patients require repeated treatment and long-term monitoring.

“Laser Makes Vision Better Immediately”

PRP is primarily intended to prevent future severe visual loss.

It does not usually restore vision already lost from macular ischaemia or retinal detachment.

“If I Need Laser, the Eye Is Already Blind”

False.

Laser is often used while vision is still good to prevent bleeding and retinal detachment.

“Controlling Sugar Means I No Longer Need Eye Examinations”

False.

Good control reduces risk but does not eliminate it.

Frequently Asked Questions

How Often Should a Person With Diabetes Have an Eye Examination?

The interval depends on:

• Type of diabetes
• Duration
• Existing retinopathy
• Glucose control
• Pregnancy
• Kidney disease
• Previous treatment

Many patients require annual screening, while selected patients with repeated normal examinations and stable control may be reviewed every one to two years.

Can Diabetic Retinopathy Improve?

Mild retinal changes may stabilise or partially regress with improved systemic control.

Anti-VEGF treatment may improve the apparent retinopathy severity.

However, damaged or closed capillaries may not return to normal.

Can Glasses Correct Diabetic Retinopathy?

Glasses can correct:

• Short-sightedness
• Long-sightedness
• Astigmatism

They cannot correct retinal swelling, bleeding, ischaemia or detachment.

Why Does My Prescription Change When My Sugar Changes?

Blood-glucose variation can alter the water content and focusing power of the natural lens.

Wait until glucose is reasonably stable before purchasing expensive new spectacles whenever clinically appropriate.

Is DME the Same as PDR?

No.

DME is macular swelling caused by leakage.

PDR is abnormal new blood-vessel growth.

An eye may have either condition or both.

Do All Patients With DME Need Injections?

No.

Treatment depends on:

• Whether the centre is involved
• Visual acuity
• OCT findings
• Rate of change
• Patient circumstances

Selected eyes with centre-involving DME and good vision may be observed closely.

Are Anti-VEGF Injections Painful?

The eye is numbed first.

Most patients feel:

• Pressure
• A brief pinch
• Mild grittiness afterwards

Severe increasing pain is not normal.

How Long Will Injection Treatment Continue?

Some patients require treatment for months.

Others need intermittent injections for years.

The interval may lengthen when the retina remains dry and stable.

Can I Stop Injections When Vision Improves?

Do not stop without discussing the treatment plan.

Fluid or abnormal vessels may return before symptoms become noticeable.

Which Is Better for PDR: Laser or Injections?

Both can be effective.

The choice depends on:

• DME
• Follow-up reliability
• Cost
• Pregnancy
• Visual-field needs
• Previous bleeding
• Retinal traction
• Patient preference

Can Diabetic Retinopathy Return After Laser?

Yes.

PRP reduces the risk but does not remove the underlying diabetes.

Additional laser or injections may be required.

Can a Vitreous Haemorrhage Clear by Itself?

Some haemorrhages clear gradually.

Urgent assessment is still required to determine:

• Whether the retina is attached
• Whether active new vessels remain
• Whether laser, injections or surgery are required

Can Diabetic Retinopathy Cause Floaters?

Yes.

New floaters or cobwebs may indicate bleeding from abnormal vessels.

Does Diabetic Retinopathy Cause Eye Pain?

Usually not.

Pain may indicate neovascular glaucoma or another eye condition.

Can Cataract Surgery Be Performed?

Yes.

The retinal condition should be assessed and treated appropriately before, during or after surgery.

Does Pregnancy Always Worsen Retinopathy?

No.

The risk depends on the pre-pregnancy retinal stage and systemic factors.

Early examination and appropriate follow-up are essential.

When to Seek Urgent Review

Arrange urgent same-day eye assessment for:

• New floaters or cobwebs
• A sudden shower of black spots
• A sudden red or smoky haze
• Sudden blurred vision
• A curtain or missing visual field
• Sudden distortion
• Rapid loss of central vision
• Eye pain with redness or nausea
• Trauma to an eye with advanced retinopathy
• New symptoms after recent retinal treatment

Do not wait for the next routine diabetes appointment.

A Diabetic-Eye-Care Checklist

Every Day

• Take diabetes medication as prescribed.
• Monitor glucose according to the diabetes plan.
• Take blood-pressure medication correctly.
• Avoid smoking.
• Report new visual symptoms.

At Medical Reviews

Discuss:

• HbA1c
• Blood pressure
• Cholesterol
• Kidney function
• Anaemia
• Pregnancy plans
• Medication changes
• Episodes of severe hypoglycaemia

At Eye Appointments

Bring:

• Medication list
• Recent HbA1c result
• Blood-pressure information
• Details of previous eye injections
• Previous laser or surgical reports
• A description of new symptoms

Do Not Miss Follow-Up

This is particularly important when receiving:

• Anti-VEGF injections
• PRP
• Treatment for PDR
• Treatment during pregnancy
• Monitoring for tractional retinal detachment

The Bottom Line

Diabetic retinopathy is damage to the retinal circulation caused by diabetes.

It may progress through:

• Mild NPDR
• Moderate NPDR
• Severe NPDR
• Proliferative diabetic retinopathy

Diabetic macular oedema may occur at any stage.

Early disease often causes no symptoms. Regular retinal screening is therefore essential even when vision is clear.

The most important risk factors include:

• Duration of diabetes
• Long-term glucose exposure
• High blood pressure
• Abnormal cholesterol
• Kidney disease
• Pregnancy
• Smoking

Treatment may include:

• Systemic diabetes management
• Observation
• Anti-VEGF injections
• Intravitreal steroid treatment
• Focal or grid laser
• Panretinal photocoagulation
• Vitrectomy surgery

For centre-involving DME with visual impairment, anti-VEGF injections are generally the main initial treatment.

For PDR, both PRP and repeated anti-VEGF treatment are effective options. The best choice depends on the retinal findings, follow-up reliability, treatment burden and the presence of macular oedema.

Seek urgent assessment for:

• Sudden floaters
• Cobwebs
• A red or dark haze
• A curtain
• Sudden blurred vision
• Eye pain with redness

Diabetic retinopathy can cause permanent visual loss, but blindness is not inevitable.

The combination of early screening, good systemic care, timely retinal treatment and reliable follow-up gives patients the best chance of maintaining useful vision throughout life.

References

1. American Diabetes Association Professional Practice Committee. Retinopathy, neuropathy, and foot care: Standards of Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl 1)–S276.
2. American Academy of Ophthalmology Retina/Vitreous Panel. Diabetic Retinopathy Preferred Practice Pattern. San Francisco: American Academy of Ophthalmology; 2024.
3. Teo ZL, Tham YC, Yu M, et al. Global prevalence of diabetic retinopathy and projection of burden through 2045: systematic review and meta-analysis. Ophthalmology. 2021;128(11):1580–1591. doi:10.1016/j.ophtha.2021.04.027. PMID: 33940045.
4. Diabetes Control and Complications Trial Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med. 1993;329(14):977–986. doi:10.1056/NEJM199309303291401. PMID: 8366922.
5. UK Prospective Diabetes Study Group. Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes. Lancet. 1998;352(9131):837–853. doi:10.1016/S0140-6736(98)07019-6. PMID: 9742976.
6. UK Prospective Diabetes Study Group. Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38. BMJ. 1998;317(7160):703–713. PMID: 9732337.
7. Chew EY, Ambrosius WT, Davis MD, et al. Effects of medical therapies on retinopathy progression in type 2 diabetes. N Engl J Med. 2010;363(3):233–244. doi:10.1056/NEJMoa1001288. PMID: 20587587.
8. Diabetic Retinopathy Clinical Research Network. Aflibercept, bevacizumab, or ranibizumab for diabetic macular edema. N Engl J Med. 2015;372(13):1193–1203. doi:10.1056/NEJMoa1414264. PMID: 25692915.
9. Baker CW, Glassman AR, Beaulieu WT, et al. Effect of initial management with aflibercept versus laser photocoagulation versus observation on vision loss among patients with centre-involved diabetic macular edema and good visual acuity. JAMA. 2019;321(19):1880–1894. doi:10.1001/jama.2019.5790. PMID: 31037289.
10. Gross JG, Glassman AR, Liu D, et al. Five-year outcomes of panretinal photocoagulation versus intravitreous ranibizumab for proliferative diabetic retinopathy. JAMA Ophthalmol. 2018;136(10):1138–1148. doi:10.1001/jamaophthalmol.2018.3255. PMID: 30043039.
11. Wykoff CC, Abreu F, Adamis AP, et al. Efficacy, durability, and safety of intravitreal faricimab with extended dosing in patients with diabetic macular oedema: YOSEMITE and RHINE. Lancet. 2022;399(10326):741–755. doi:10.1016/S0140-6736(22)00018-6. PMID: 35085503.
12. Brown DM, Boyer DS, Do DV, et al. Intravitreal aflibercept 8 mg in diabetic macular oedema: PHOTON 48-week results. Lancet. 2024;403(10432):1153–1163. doi:10.1016/S0140-6736(23)02577-1. PMID: 38461843.
13. Boyer DS, Yoon YH, Belfort R Jr, et al. Three-year, randomised, sham-controlled trial of dexamethasone intravitreal implant in patients with diabetic macular edema. Ophthalmology. 2014;121(10):1904–1914. doi:10.1016/j.ophtha.2014.04.024. PMID: 24907062.
14. Early Treatment Diabetic Retinopathy Study Research Group. Photocoagulation for diabetic macular edema: ETDRS Report Number 1. Arch Ophthalmol. 1985;103(12):1796–1806. PMID: 2866759.
15. Antoszyk AN, Glassman AR, Beaulieu WT, et al. Effect of intravitreous aflibercept versus vitrectomy with panretinal photocoagulation on visual acuity in patients with vitreous haemorrhage from proliferative diabetic retinopathy. JAMA. 2020;324(23):2383–2395. doi:10.1001/jama.2020.23027. PMID: 33320223.