Widefield retinal imaging: what it is and what to expect
Widefield retinal imaging is a photograph of the inside back wall of the eye. An ultra-widefield camera records a much larger area of the retina in one picture than a standard retinal camera does, reaching well out towards the edges.
In brief
- What it is: a colour photograph of the retina covering a wide area.
- What it feels like: painless. A brief bright flash.
- How long: a few minutes for both eyes.
- Preparation: none. Dilating drops are sometimes used.
- What it is for: a record of the retina that can be compared at later visits.
What the photograph shows
The retina lines the inside of the eye like wallpaper on the inside of a ball. A standard retinal photograph records the central part: the optic nerve, the macula and the main blood vessels. A widefield photograph also records the mid and outer retina, where some conditions begin.
On the picture the doctor can see the optic nerve, the macula, the retinal blood vessels, any bleeding, deposits or pigment changes, and many lesions lying away from the centre.
Why it is done
- Diabetes: diabetic changes can appear in the outer retina as well as the centre. A wide photograph records their extent and gives a baseline for the next visit. See diabetic eye screening.
- Blocked retinal veins and other conditions of the retinal blood vessels: to record how much of the retina is involved.
- Lesions that are being watched: for example a pigmented spot or an area of thinning at the edge of the retina, where the question at each visit is whether it has changed.
- High short-sightedness: the outer retina is more often thin in very short-sighted eyes, and a record is useful.
- Explaining findings: seeing your own retina on the screen makes the doctor's explanation easier to follow.
It is not a routine test for every visit. It is advised when a record of the retina would help, and the reason is explained beforehand.
What you will experience
- You sit at the camera and rest your chin and forehead on a support.
- You look at a target light inside the camera with one eye.
- The technician lines up the camera and asks you to open your eyes wide. There is a brief bright flash as the picture is taken.
- The other eye is photographed in the same way. A picture is sometimes repeated if a blink or the eyelashes covered part of the view.
The test is painless and nothing touches the eye. After the flash you may see a coloured after-image for a short while. If dilating drops are used, near vision is blurred for a few hours. See before your visit for what dilation means for driving and reading.
How long it takes
A few minutes for both eyes. If dilating drops are used, add the 20 to 30 minutes the drops take to work.
How to prepare
- No fasting and no change to your medicines or eye drops.
- Bring earlier retinal photographs or reports if you have them.
- If dilation is likely, arrange not to drive yourself home, and bring sunglasses.
- Heavy eye make-up on the lashes can get in the way of the picture.
What the result can tell
- What the retinal surface looks like across a wide area on the day of the photograph.
- Whether bleeding, deposits, abnormal vessels or other visible changes are present, and where.
- Whether anything has changed since an earlier photograph.
What the result cannot tell
- It does not replace the doctor's examination. A photograph is flat. The doctor examining a dilated eye sees the retina in depth and can look at any area from different angles.
- The far edge can be missed. Eyelids and lashes can cover the upper and lower edges of the picture, so the outermost retina is not always recorded. A person with new flashes, floaters or a shadow in the vision needs a dilated examination, whatever a photograph shows.
- It shows the surface, not the layers. Swelling within the retina is seen and measured on an OCT scan, not on a photograph.
- It does not show blood flow or leakage. Those need other tests.
- Image quality varies. Cataract, a small pupil or haze inside the eye can make the picture less clear.
- It does not measure vision or eye pressure.
Widefield imaging at the hospital
Dr. P. Siva Reddy Eye Hospital has ultra-widefield retinal imaging on site. The doctor reads the photograph together with your examination. How the different retina tests fit together is described on the retina diagnostics page.
Frequently asked questions
Is widefield retinal imaging painful?
No. It is a photograph and it is painless. Nothing touches the eye. There is a brief bright flash as the picture is taken.
How long does it take?
A few minutes for both eyes. Each picture takes a moment, and one may be retaken if you blinked.
Do my eyes need to be dilated?
Not always. Many pictures can be taken without drops. Dilating drops give a clearer and wider view in some eyes, and the doctor may dilate the pupils anyway in order to examine the retina directly.
Does the photograph replace a dilated retina examination?
No. The photograph is a record that supports the examination. The doctor decides whether a dilated examination is also needed, and for many conditions it is.
Is the flash harmful?
The flash is brief. You may see a coloured after-image for a short while afterwards, as after a camera flash. It fades.
Why is a photograph taken if the doctor has already looked?
A photograph is a lasting record. At a later visit, it lets the doctor compare the retina directly with how it looked before, and it lets you see what is being described.
How is this different from an OCT scan?
The photograph shows the surface of the retina across a wide area. An OCT scan shows a small central area in cross-section, layer by layer. They answer different questions and are often used together.
Related pages
Appointments and contact
You can reach Dr. P. Siva Reddy Eye Hospital on WhatsApp or by phone during OPD hours.
OPD hours: Monday to Saturday, 10 AM to 2 PM and 4:30 PM to 7 PM. Closed on Sunday.