Fundus Photography: Retinal Imaging for Diabetic Retinopathy, Glaucoma and Retinal Disease

Key takeaways

• What it shows: A colour photograph of the back of the eye, retina, macula, optic disc and vessels.
• What it is used for: Screening and monitoring of diabetic retinopathy, age-related macular degeneration, glaucomatous optic disc change, hypertensive and retinal vascular disease.
• What it cannot do: Fundus photography does not measure intraocular pressure, visual fields, retinal thickness or leakage, and a single photograph may not cover the far peripheral retina.
• Image quality matters: Cataract, small pupils, dry eye and poor fixation can degrade or obscure the image.
• Interpretation is clinical: Photographs support, but do not replace, an examination and interpretation by the ophthalmologist who requested the test.

At a glance

Also known as

• Fundus photo / retinal photography / retinal imaging
• Colour fundus photograph (CFP)
• Eye screening photo, "retina ka photo", "aankh ka retina test" in everyday Indian usage
• Non-mydriatic fundus photography (taken without dilating drops)
• Ultra-widefield retinal imaging (a distinct, wider-angle technique)

What fundus photography is

The fundus is the inside back surface of the eye. A fundus camera shines light through the pupil, focuses on the retina, and records a colour digital image. The photograph is a permanent, shareable record that can be placed side by side with images taken months or years later.

Some units use a standard mydriatic tabletop camera, some use a non-mydriatic camera that works through an undilated pupil in a darkened room, and some use ultra-widefield systems that capture a much larger area of retina in one shot. Portable and smartphone-based fundus cameras are increasingly used in community diabetic retinopathy screening in India. Image quality and field of view differ between these systems, so a report from one device is not directly interchangeable with another.

Why fundus photography is done

• Diabetic retinopathy screening and grading: to document microaneurysms, dot and blot haemorrhages, hard exudates and new vessels.
• Age-related macular degeneration: to record drusen, pigment change and scarring.
• Glaucoma: to photograph the optic disc so that cupping and rim change can be compared over years. The photograph supports, but does not make, a glaucoma diagnosis.
• Hypertensive and retinal vascular disease: vein or artery occlusion, arteriolar narrowing, cotton wool spots.
• Retinal tears, degenerations and detachment: documentation of peripheral lesions, usually alongside a dilated indirect examination.
• Papilloedema and optic disc swelling: baseline documentation in neurological presentations.
• Retinopathy of prematurity in specialist neonatal units, using dedicated wide-field paediatric cameras.
• Drug safety monitoring, for example with hydroxychloroquine or ethambutol, as part of a wider protocol that includes other tests.

Who should get this test

• People with diabetes: retinal screening is recommended from diagnosis in type 2 diabetes and within a few years of diagnosis in type 1 diabetes, then at intervals decided by the ophthalmologist based on findings and diabetes control. Screening intervals shorten in pregnancy and with poor control.
• People with known or suspected glaucoma, or a strong family history, for baseline disc documentation.
• Older adults with reduced or distorted central vision being assessed for macular degeneration.
• People with high blood pressure and visual symptoms, or when hypertensive retinal change is suspected.
• High myopes requiring documentation of peripheral retinal degeneration.
• People on retinotoxic medication under a monitoring protocol.
• Preterm infants meeting screening criteria, in a specialist setting.

Fundus photography is not a routine test for every adult with normal vision and no risk factors. The decision rests with the treating eye specialist.

What fundus photography cannot detect or exclude

Fundus photography is a surface picture. It has clear limits.

• It does not measure intraocular pressure. Tonometry is a separate test. A normal-looking disc photograph does not exclude glaucoma, and a suspicious disc does not confirm it.
• It does not measure vision or visual field. Perimetry is needed for functional loss.
• It does not show retinal thickness, fluid or layer structure. Macular oedema can be present despite an unremarkable photograph; optical coherence tomography (OCT) is far more sensitive for this.
• It does not show leakage or blood flow dynamically. Fluorescein angiography or OCT-angiography is required to assess leakage, ischaemia and some new vessels.
• Standard fields may miss the far periphery. Peripheral tears, holes and lattice degeneration can be missed unless ultra-widefield imaging or a dilated indirect ophthalmoscopic examination with scleral indentation is performed.
• It does not assess the front of the eye: cornea, lens, anterior chamber angle or eyelids.
• It cannot see through dense media opacity. Cataract, vitreous haemorrhage or corneal scarring may make the retina unphotographable; in that situation B-scan ultrasound may be used.
• It does not grade optic nerve function in isolation.

A fundus photograph reported as showing no abnormality means no abnormality was seen in the photographed area on that day. That is not the same as disease being excluded. If your vision changes or symptoms persist despite a normal photograph, go back to your eye doctor rather than waiting for the next scheduled screening.

Related but different examinations

These tests answer different questions. Which one comes first depends on the presentation: sudden distortion of central vision usually leads to OCT of the macula; a flashing-lights-and-floaters presentation needs a dilated peripheral examination; routine diabetes screening commonly starts with fundus photography.

How to prepare

Preparation is set by the unit performing the test and by the camera in use. Your unit's written instructions take precedence over any general guidance.

• Bring your glasses and current prescription, plus previous eye reports and photographs for comparison.
• Bring a list of your medicines and tell staff about glaucoma, previous eye surgery, or a history of allergy to eye drops.
• Contact lenses may need to be removed; ask your unit in advance.
• Eye make-up is best avoided on the day, as it can smear the chin rest and the image.
• Bring sunglasses and a companion if dilating drops are planned.
• No fasting is needed for plain colour fundus photography. If you have diabetes, eat and take your usual medicines as prescribed unless your treating doctor has told you otherwise, do not skip meals or alter diabetes medication for this test on your own.
• Do not drive yourself home if drops are used; blurring and glare typically last a few hours and vary between people.

If you have glaucoma or a narrow anterior chamber angle

Dilating drops can, uncommonly, trigger an acute angle-closure attack in susceptible eyes. Tell the team if you have been told you have narrow angles or have had a laser iridotomy. Severe eye pain, redness, haloes, vomiting or sudden vision loss after dilation needs emergency assessment.

If you are pregnant

Fundus photography itself involves no radiation and no injected dye. Diabetic retinopathy can progress during pregnancy, so screening is often brought forward. Discuss the use of dilating drops with the eye team and your obstetrician.

Children and infants

Paediatric imaging uses lower-concentration dilating drops and dedicated cameras. Screening for retinopathy of prematurity is performed only in specialist neonatal units under defined protocols.

Older adults and people with cataract

Dense cataract scatters light and can make images hazy or unusable. The team may proceed with a dilated clinical examination or alternative imaging instead. Older adults may take longer to recover from dilation glare.

People with cardiac disease or on multiple medicines

Phenylephrine-containing dilating drops can raise blood pressure slightly. Tell staff about uncontrolled hypertension or significant heart disease so an alternative drop can be considered. Do not stop or change any prescribed medicine yourself, speak to the prescriber.

What happens during fundus photography

• Check-in and history: vision, symptoms, diabetes duration and medicines are recorded.
• Drops, if required: dilating drops sting briefly and take time to work. Pupils may be checked before imaging.
• Positioning: you rest your chin and forehead against the camera and look at a small fixation light. Keeping still and blinking when told helps image quality.
• Capture: a bright flash is fired for each field. Several fields may be taken per eye for diabetic retinopathy grading. Afterimages and dazzle for a minute or two are expected.
• Review: the operator checks image quality and repeats any blurred field.

How long the process takes

• Imaging itself: usually only a few minutes per eye.
• If dilating drops are used: allow additional waiting time for the pupils to open, which varies with iris colour, age and diabetes; darker irides often dilate more slowly.
• Recovery: blurred near vision and glare sensitivity after dilation commonly last a few hours, sometimes longer.
• Total visit: plan for a longer appointment than the imaging time alone, particularly if OCT, pressure checks or a consultation are booked the same day.

Understanding your report

A fundus photography report describes what is visible in each photographed field. Common terms include:

• Optic disc: described by colour, margins and cup-to-disc ratio. A large cup can be physiological, especially in large discs; it is not by itself a diagnosis of glaucoma.
• Macula: described by foveal reflex, drusen, pigment change or scarring.
• Vessels: calibre, tortuosity, arteriovenous crossing changes, occlusions.
• Retinal lesions: microaneurysms, dot/blot haemorrhages, hard exudates, cotton wool spots, neovascularisation, laser scars.
• Periphery: commented on only if adequately imaged.

Diabetic retinopathy is usually reported using a recognised severity scale (for example no apparent retinopathy, mild, moderate or severe non-proliferative, and proliferative), with macular oedema described separately. Grading is a judgement made on visible features and can differ between graders and between camera fields. Ask your ophthalmologist which scale was used and what your grade means for your follow-up interval.

A grade is not a prediction. Results vary depending on individual clinical circumstances, and the same photograph can mean different things depending on your vision, diabetes control, blood pressure, previous treatment and OCT findings. Never self-interpret the images or the wording of the report, the doctor who requested the test must interpret it in clinical context.

When results can be misleading

Findings that can appear falsely abnormal or be over-called

• Large physiological optic cups in large discs, mistaken for glaucomatous cupping.
• Myopic tilted discs and peripapillary atrophy, which distort disc assessment.
• Tilted or off-centre images and lens glare artefacts, which can mimic haemorrhages or drusen.
• Dust or fingerprint on the camera optics, producing repeating spots across images.
• Normal variants such as myelinated nerve fibres or a prominent choroidal pattern in lightly pigmented fundi.

Findings that can be falsely missed or under-called

• Macular oedema: often invisible on a flat colour photograph but clearly seen on OCT.
• Peripheral retinal tears and detachment outside the imaged field.
• Small pupils (long-standing diabetes, older age, pilocarpine use) producing dark, incomplete images.
• Media opacity: cataract, corneal scarring, dry eye, vitreous haze, reducing contrast and hiding subtle lesions.
• Poor fixation in people with reduced central vision, nystagmus or in young children.
• Single-field imaging when protocol requires multiple fields; fewer fields means lower sensitivity.

If the report says the image quality was inadequate or ungradable, the test needs repeating or a dilated clinical examination arranged. An ungradable image is not a normal result.

Risks and safety

Plain colour fundus photography

No injection, no radiation and no contact with the eye. The main effects are brief dazzle and afterimages from the flash. Photosensitive individuals should mention epilepsy or flash sensitivity beforehand.

Photography with dilating drops

• Stinging on instillation, blurred near vision and glare for several hours.
• Reduced ability to drive, read or work at a screen until the effect wears off.
• Uncommon: local allergic reaction with redness, itching or lid swelling.
• Uncommon but important: acute angle-closure glaucoma in anatomically predisposed eyes.
• In children, systemic effects of cyclopentolate or atropine such as flushing, dry mouth or irritability can occur; doses are weight-appropriate in paediatric practice.

Non-mydriatic photography

Avoids drop-related effects but is more likely to produce ungradable images in small pupils or cataract, which may mean a repeat visit with dilation.

Fluorescein angiography: a different test, different risk profile

Safety statements about plain fundus photography do not apply to angiography. Fluorescein dye commonly causes transient nausea and temporary yellowing of skin and urine, and carries a small risk of serious allergic reaction. The risks of the two tests should not be treated as the same.

Special situations

Diabetes on glucose-lowering therapy

No fasting is required. Continue meals and prescribed medicines as usual. Rapid improvement in blood glucose after starting intensive treatment can transiently worsen retinopathy, so screening intervals may be tightened, discuss this with your diabetes team and ophthalmologist.

Pregnancy

Diabetic retinopathy may progress faster in pregnancy, and screening is usually arranged early and repeated. Gestational diabetes alone is generally managed differently from pre-existing diabetes; follow the plan your obstetric and eye teams set.

Children

Imaging may need a parent's help with fixation. Handheld wide-field cameras are used in infants. Cycloplegic drops blur near vision for longer in children, plan for time away from school work.

Older adults

Cataract, small pupils and dry eye reduce image quality. Falls risk after dilation is real; arrange an escort.

Chronic kidney disease and heart failure

Fundus photography needs no injected contrast and no fluid loading, so it poses no fluid or renal burden. Diabetic kidney disease and retinopathy often coexist, and retinal findings may prompt closer renal review.

People with visual impairment or poor fixation

Steadier results may be obtained with widefield or handheld systems, or the team may rely on a clinical examination instead.

Fundus photography in the Indian context

• Diabetes burden: India has one of the largest diabetes populations in the world, and diabetic retinopathy screening capacity is a recognised public health priority. Community and teleophthalmology screening using portable fundus cameras is widely used to reach people who cannot attend a hospital eye clinic.
• Teleophthalmology and AI grading: Several Indian screening programmes transmit fundus images to a central grading centre, and AI-assisted grading tools are in use in some settings. AI grading is a triage aid; images flagged as abnormal, and ungradable images, still require review by an eye specialist.
• Glaucoma: glaucoma is frequently detected late in India because early disease is symptomless. Disc photographs are valuable as a baseline for future comparison but must be combined with intraocular pressure measurement and visual fields.
• Nutritional and systemic contributors: anaemia, uncontrolled hypertension and chronic kidney disease are common and can influence retinal appearance and disease progression.
• Drug-related monitoring: ethambutol used in anti-tubercular therapy can affect the optic nerve, and hydroxychloroquine is used widely in rheumatology. Both require structured eye monitoring that goes beyond a fundus photograph alone.
• Regulation: fundus photography is an ophthalmic imaging test and is not covered by the PC-PNDT Act, which applies to ultrasound and prenatal diagnostic procedures. Digital retinal images and any linked personal data are personal data under the Digital Personal Data Protection Act, 2023, and should be stored and shared accordingly. Advertising of eye tests must comply with the Drugs and Magic Remedies (Objectionable Advertisements) Act, 1954, and NMC professional conduct rules, no test can promise to prevent blindness.

Cost and insurance in India

Charges for fundus photography vary widely across the country and cannot be quoted as a single national figure. Confirm the price with the facility before your appointment.

Factors that affect what you pay:

• City and type of facility, government, charitable eye hospital, standalone clinic or corporate hospital.
• Technology used, standard fundus camera versus ultra-widefield or autofluorescence imaging.
• Number of eyes and number of fields imaged.
• Whether dilating drops, OCT, tonometry or perimetry are bundled into a package.
• Whether a specialist consultation and formal grading report are included.
• Camp or community screening programmes, which are often subsidised or free.

Insurance: outpatient diagnostic tests are frequently not covered under standard indemnity health insurance unless linked to an admission or covered by an OPD rider. Diabetic retinopathy screening may be covered under specific diabetes care programmes or government schemes. Check with your insurer and the hospital billing desk in advance.

Myths and facts

Frequently asked questions

Does fundus photography hurt?

Fundus photography itself is painless and nothing touches the eye. Dilating drops, if used, sting for a few seconds. The camera flash is bright and leaves a brief afterimage. Most people find the main inconvenience is the blurred vision and glare sensitivity afterwards rather than the photography itself.

Will I need dilating drops?

It depends on the camera and on your pupil size. Non-mydriatic cameras often work without drops, particularly in younger eyes with clear lenses. Drops are usually needed when pupils are small, cataract is present, or wide, multi-field or peripheral imaging is required. The imaging team decides on the day.

Can I drive home afterwards?

Not if dilating drops were used. Blurring of near vision and sensitivity to glare typically last a few hours and can last longer in some people. Arrange a companion or transport, and bring sunglasses. Without dilation, most people can resume normal activity straight away after the dazzle settles.

How often should fundus photography be repeated if I have diabetes?

The interval depends on the retinopathy grade, diabetes duration and control, blood pressure, kidney function and pregnancy status. Some people are reviewed annually; those with more advanced changes are seen far more frequently. Your ophthalmologist sets and adjusts the interval, so follow the date you are given.

Is fundus photography better than OCT?

Neither is better; they answer different questions. Fundus photography shows the surface appearance of the retina in colour and is well suited to screening and documentation. OCT shows cross-sectional retinal layers and detects fluid or swelling that a photograph can miss. They are frequently used together.

Can fundus photography detect retinal detachment?

It can show detachment or a tear if the abnormality lies within the imaged field, and ultra-widefield systems image far more periphery. However, a standard fundus photograph can miss peripheral tears. Flashes, new floaters or a shadow in the vision need an urgent dilated examination, not just a photograph.

Is fundus photography safe in pregnancy?

The imaging involves no radiation and no injected dye, so photography itself poses no known concern in pregnancy. Dilating drops are absorbed in small amounts and their use should be discussed with your eye team and obstetrician. Retinal screening is often brought forward in pregnancy for women with pre-existing diabetes.

What if my images are reported as ungradable?

Ungradable means the pictures were not clear enough to assess, usually because of small pupils, cataract, dry eye or movement. It is not a normal result and it is not an abnormal one. The test is normally repeated with dilation, or a dilated clinical examination is arranged instead.

Can children have fundus photography?

Yes. Children are imaged with paediatric-appropriate dilating drops, and infants with handheld wide-field cameras in specialist settings, such as retinopathy of prematurity screening. Cooperation and fixation are the main practical challenges, and cycloplegic drops blur near vision for longer in children than in adults.

Sources

• International Council of Ophthalmology, Guidelines for Diabetic Eye Care.
• American Academy of Ophthalmology, Preferred Practice Pattern guidelines on Diabetic Retinopathy, Age-Related Macular Degeneration, Primary Open-Angle Glaucoma and Posterior Vitreous Detachment, Retinal Breaks and Lattice Degeneration.
• International Clinical Diabetic Retinopathy and Diabetic Macular Oedema Disease Severity Scales.
• All India Ophthalmological Society and Vision 2020 India, diabetic retinopathy screening resources.
• Government of India, National Programme for Control of Blindness and Visual Impairment.
• Digital Personal Data Protection Act, 2023 (Government of India).
• Drugs and Magic Remedies (Objectionable Advertisements) Act, 1954 (Government of India).