What is retinal imaging?

Retinal imaging captures a wide-angle photograph of the back of the eye — the retina, macula, optic nerve, and blood vessels. It documents the current state of your eye health and provides a baseline for comparison at future exams. Changes between visits — even subtle ones — are easier to identify when there is a reference photograph on file.

OCT (optical coherence tomography) is a non-invasive scan that produces cross-sectional images of the retinal layers and optic nerve. Think of it like an ultrasound, but using light rather than sound. It can reveal structural changes in tissue that are invisible to direct examination — including early signs of macular degeneration, glaucoma, and diabetic retinopathy.

Is retinal imaging or OCT covered by OHIP?

Retinal photography and OCT are not covered by OHIP. They are billed as additional diagnostic services. The fee is typically charged at the time of your exam. Most private benefit plans include some coverage for diagnostic imaging — check your plan details or ask your optometrist's office to look into your coverage.

Do I need imaging at every exam?

Not necessarily. Your optometrist will recommend imaging based on your individual risk profile — age, family history, existing conditions like diabetes or glaucoma, and any clinical findings during the exam. Some patients benefit from imaging at every annual visit; others may only need it when a specific concern arises.

Will I see the images?

Yes. Retinal images and OCT scans should be reviewed with you. Your optometrist should show you what was found, explain what normal findings look like versus what is being monitored, and tell you what changes — if any — would prompt a follow-up.

Meibography is a specialized infrared imaging technique used in dry eye assessment. It visualizes the meibomian glands inside the eyelids — the glands responsible for producing the oily layer of your tear film. It can reveal gland atrophy or dropout that isn't apparent from symptoms alone, which helps guide dry eye treatment.

Retinal Imaging and OCT Eye Tests Explained

Your optometrist examines your eyes using a slit lamp and ophthalmoscope — instruments that allow direct visualization of the structures inside and at the back of the eye. But there are limits to what direct examination can reveal. Advanced imaging fills those gaps: it documents what was found, detects changes that can't be seen with the naked eye, and provides data that can be compared year over year.

Retinal photography

Retinal photography — sometimes called fundus photography — captures a wide-field photograph of the posterior segment of the eye: the retina, macula (the region responsible for central vision), optic nerve head, and retinal blood vessels.

What it's useful for:

Establishing a baseline. A photograph taken today becomes the reference point for every future exam. Subtle changes in the optic nerve or macula are far easier to identify when a clear prior image exists.
Documenting findings. Suspicious lesions, drusen (early AMD deposits), optic nerve cupping, or vascular changes can be photographed and tracked over time.
Diabetic retinopathy screening. Retinal photographs allow systematic review of the peripheral retina for haemorrhages, exudates, and new vessel growth — the hallmarks of diabetic eye disease.
Monitoring high myopia. Highly myopic eyes are prone to specific retinal changes. Photography provides a trackable record.

The process is quick and non-invasive. You look at a fixation target inside the camera; a brief flash captures the image. Dilating drops may or may not be required, depending on the camera and the reason for imaging.

OCT (optical coherence tomography)

OCT is a scanning technology that uses low-coherence near-infrared light to produce cross-sectional images of tissue — similar in principle to ultrasound, but with much higher resolution. In eye care, it's most commonly used to image the retina and optic nerve in detail that direct examination cannot match.

Macular OCT

The macula is the small central region of the retina responsible for sharp, detailed vision — reading, recognizing faces, driving. Macular OCT produces a layered cross-section of this tissue, revealing:

Age-related macular degeneration (AMD). OCT can detect the earliest structural signs of AMD — drusen deposits, pigment epithelial detachment, and the presence of subretinal fluid that indicates wet AMD — often before significant vision change is noticeable.
Diabetic macular oedema. Fluid accumulation in the macula from diabetic retinopathy appears clearly on OCT and guides treatment decisions.
Epiretinal membrane and macular hole. Conditions affecting the surface or centre of the macula are precisely characterized by OCT.

Optic nerve OCT

The optic nerve is the cable that carries visual signals from the retina to the brain. OCT of the optic nerve and the surrounding retinal nerve fibre layer (RNFL) is a core tool in glaucoma assessment.

Glaucoma damages retinal nerve fibres before central vision is affected. OCT can quantify RNFL thickness and compare it against age-matched normative data — flagging thinning that is statistically significant, even when a patient has no symptoms and appears normal on a visual field test. This makes it particularly valuable for:

Early glaucoma detection in patients with suspicious optic nerve appearance or elevated pressure
Glaucoma progression monitoring — tracking whether nerve fibre loss is continuing despite treatment

Meibography

Meibography is an imaging technique used specifically in dry eye assessment. It visualizes the meibomian glands — the rows of glands inside the upper and lower eyelids that produce the lipid (oily) layer of the tear film.

Meibomian gland dysfunction (MGD) is one of the most common causes of chronic dry eye. The glands can become blocked, atrophied, or dropout entirely — a process that can't be assessed by looking at the eye's surface alone. Infrared meibography reveals the structure and integrity of these glands, allowing targeted treatment and providing a baseline for monitoring response to therapy.

Why imaging matters for asymptomatic conditions

Many of the conditions that advanced imaging is designed to detect — early AMD, early glaucoma, mild diabetic retinopathy, meibomian gland atrophy — produce no noticeable symptoms in their early stages. Vision may feel completely normal. A comprehensive examination helps, but photography and OCT provide an additional layer of detection.

The value of imaging increases over time. A single set of images is useful. A longitudinal record — images from five or ten years of annual exams — is far more powerful, because it allows your optometrist to identify change, not just status.

What to ask at your next exam

If imaging hasn't been part of your routine exams, or if you're not sure what was done at your last visit, it's worth asking:

Has retinal photography been done, and is it on file?
Is an OCT of the macula or optic nerve recommended for me?
What risk factors — if any — make imaging particularly important in my case?

Your optometrist will tell you what's recommended for your individual situation versus what's optional, and what the images showed.

Retinal Imaging and OCT: What the Tests at Your Eye Exam Actually Show