Lights, Camera, Eyes: The Benefits of Topography and Fundus Photography
At a glance: Every Bolt Eye Group patient gets two kinds of eye pictures for $39. Corneal topography maps the front of your eye and screens for keratoconus. Fundus photography takes photos of the retina and optic nerve at the back of your eye. Your doctor uses them to confirm your eyes are healthy, and shows them to you.
Most people think of an eye exam as reading letters on a chart. The chart tells us how well you see. It doesn't tell us much about the health of your eye. These two pictures fill that gap, and they take only a few minutes.
What is corneal topography?
The cornea is the clear dome at the front of your eye. It covers the colored iris and the pupil, and it does most of the work of focusing light.
Corneal topography measures the shape of that dome. The result is a color map, a bit like a weather map. Warm colors show where the cornea is steeper, and cool colors show where it is flatter. A healthy cornea is smooth and evenly curved.
The test is quick and painless. You rest your chin, look at a light, and the machine takes its pictures. Nothing touches your eye.
What can topography find?
- Keratoconus. The cornea slowly thins and bulges into a cone shape. It often starts in the teens or twenties. Early on, it can look like ordinary astigmatism.
- Irregular astigmatism. Uneven curves that glasses can't fully correct.
- Changes after LASIK or other vision surgery. The map shows how the cornea has healed and whether its shape is stable.
- Scars and swelling. Past injuries or infections can leave the cornea uneven.
The map also helps us fit contact lenses. Specialty lenses, such as scleral lenses and DreamSculpt™ Ortho-K, are designed from the shape of your cornea. Our post on fixing astigmatism without surgery explains how the map guides your lens choice.
Why do we screen everyone for keratoconus?
Keratoconus is easy to miss without a map. A teen whose glasses never seem quite sharp, or whose astigmatism keeps going up, may have it and not know.
Finding it early matters more than ever. There is now an FDA-approved treatment, called corneal cross-linking, that can slow or stop keratoconus from getting worse. The earlier it's found, the more vision it can protect.
That's why topography is part of our imaging for every patient, not only for people who already have symptoms. Learn more on our keratoconus page and in our post on keratoconus and scleral lenses.
What is fundus photography?
The fundus is the inside back wall of the eye. It includes:
- the retina, the layer that senses light
- the macula, the center of the retina you use for reading and faces
- the optic nerve, which carries signals to the brain
- the blood vessels that feed them
Fundus photography uses a special camera to take a detailed color photo of this area through your pupil. It takes a few seconds and doesn't hurt. Your doctor may also use dilating drops to widen the pupil and see more of the retina.
What can retinal photos show?
- Diabetic retinopathy, which is damage to the retina's blood vessels from diabetes
- Macular degeneration
- Signs of glaucoma at the optic nerve
- Bleeding inside the eye
- Blood vessel changes that can point to high blood pressure
Many of these problems cause no pain and no blurry vision at first. A photo can catch them before you notice anything. See our pages on diabetic eye exams, glaucoma and macular degeneration.
Why keep photos if your eyes are healthy?
Even when everything looks healthy, the photos are worth having. They become your baseline. Each year we compare your new photos with the old ones, so small changes stand out.
Your doctor also shows you the photos. You can see your own retina and optic nerve and understand what the doctor is looking at.
What does the $39 cover?
- At every visit: retinal (fundus) photos and corneal topography, for $39.
- With an in-office telehealth visit: the same $39 also includes two OCT glaucoma scans, one of the optic nerve and one of the macula. OCT uses light, not ultrasound, to show the retina layer by layer. You also take all your images home on a free I-Scan Platinum Lifetime Baseline, a credit-card-size USB drive.
In-office telehealth is available at every Bolt Eye Group office. Learn how in-office telehealth works.
When should you see an eye doctor?
Book an exam if:
- it's been more than a year since your last exam
- you have diabetes, high blood pressure or a family history of glaucoma
- your glasses never seem sharp, or your prescription keeps changing
- you see more glare or halos at night
Call us right away or go to the emergency room for sudden vision loss, new flashes or floaters, or a curtain or shadow across your vision.
Frequently asked questions
Do topography and fundus photography hurt?
No. Neither test touches your eye. You look at a light for a few seconds while the machine takes pictures.
Do I need my eyes dilated?
Not always. Retinal photos are taken through your pupil, and your doctor may widen it with drops to see more. If you are dilated, bring sunglasses. Your near vision may be blurry for a few hours.
Why do I need these if my eyes feel fine?
Many eye diseases cause no symptoms early on. The map and photos can catch changes before you notice them. They also give you a baseline to compare against in future years.
Is OCT the same as an ultrasound?
No. OCT uses light to make a detailed cross-section of the retina, layer by layer. Nothing touches your eye.
Book an exam at your nearest Bolt Eye Group office
We accept VSP, EyeMed, Davis Vision, Spectera, Medicare and major medical plans, including Blue Cross Blue Shield, Aetna, UnitedHealthcare, Cigna and Humana.
Book an exam at your nearest Bolt Eye Group office in Canton, East Cobb, Lawrenceville and Riverdale, GA, or Johnson City, TN. Find your office and book online.