What is the retina?
ret•i•na [rétt'n] (plural ret•i•nas, ret•i•nae [rétt'nae]) noun a light-sensitive membrane lining the inside of the eye containing rods and cones that receive an image from the lens and send it to the brain through the optic nerve.
Light rays reflected from any object we look at enter the eye and are focused by the eye’s optical structures: cornea, iris, pupil, and lens. The final destination of the light rays is the retina, a layer of nerve tissue that lines two-thirds of the back of the eye. In the center of the retina is the macula, an area that is only 1.5 mm (0.06 in) in diameter. The macula is responsible for the clearest, most detailed vision.
The retina is made up of two types of cells: cones and rods. Cones are nerve cells that are sensitive to light, detail, and color. Millions of cone cells are packed into the macula, aiding it in providing the visual detail needed to scan the letters on an eye chart, see a street sign, or read the words in a newspaper.
Cones also produce the sensation we call color. Cones contain three different pigments, which respond either to blue, red, or green wavelengths of light. Cones mix the color signals to produce the variety of colors we see. If a person is missing one or more of the pigments, that person is said to be color-blind and has difficulty distinguishing between certain colors, such as red from green.
Rods are designed for night vision and the detection of motion and objects. They also provide peripheral vision, but they do not see as acutely as cones. Rods are insensitive to color. When a person passes from a brightly lit place to one that is dimly illuminated, such as entering a movie theater during the day, the interior seems very dark. After some minutes this impression passes and vision becomes more distinct. In this period of adaptation to the dark the eye becomes almost entirely dependent on the rods for vision, which operate best at very low light levels. Since the rods do not distinguish color, vision in dim light is almost colorless.
Light rays that reflect from the upper half of any object we look at are focused on the lower half of the retina. Rays from the lower half of the same object are focused on the upper half of the retina. This would seem to give us an upside-down picture of the world. Fortunately, these signals are rearranged when the brain processes them into an image that is right side up.
What is a retina specialist?A retina specialist is an ophthalmologist who has completed additional training in conditions which involve the vitreous body and retina of the eye. This subspecialty of ophthalmology is sometimes known as vitreoretinal medicine. Retina specialists treat a wide range of eye conditions, dealing with both adults and children, and they can be found working in hospitals and eye care clinics. The services of a vitreoretinal specialist may be recommended to a patient with an eye condition which cannot be cared for by a general ophthalmologist.
My eyes feel fine and my vision is good. Why should I have an eye exam?
Some health conditions that lead to vision problems can develop without any visual symptoms. Two of the most common retinal diseases that may develop without symptoms are diabetic retinopathy and macular degeneration.
Diabetic patients should get a dilated eye exam at least yearly because:
- Proliferative retinopathy can develop without symptoms. At this advanced stage, you are at high risk for vision loss.
- Macular edema can develop without symptoms at any of the four stages of diabetic retinopathy.
- You can develop both proliferative retinopathy and macular edema and still see fine. However, you are at high risk for vision loss.
- Your eye care professional can tell if you have macular edema or any stage of diabetic retinopathy. Whether or not you have symptoms, early detection and timely treatment can prevent vision loss.
- Age-related macular degeneration (AMD) is a disease associated with aging that gradually destroys sharp, central vision.
- AMD affects the macula, the part of the eye that allows you to see fine detail. AMD causes no pain.
- In some cases, AMD advances so slowly that people notice little change in their vision.
- In others, the disease progresses faster and may lead to a loss of vision in both eyes.
- AMD is a leading cause of vision loss in Americans 60 years of age and older.
Do you accept my insurance?
For your convenience, charges for your visit with Dr. Narain will be billed to your medical insurance by our billing contractor (Practice Med Solutions.) Vision plans like VSP cannot be billed for your appointments with us because we do not provide eyeglasses or refraction.
We accept Medicare as well as all PPO health insurance plans and are in-network for most. We also accept Physicians Medical Group of San Jose HMO plans. Please be sure to bring your insurance cards and referral forms for your first visit. If you are a member of an HMO, you must have a referral from your primary care physician prior to your first visit. Also, expect to pay your co-payment at the time of your appointment.
Please make sure to notify us of any changes in your insurance before your appointment.
For payment we accept all major credit cards, cash or personal checks.
For patients without insurance, we also accept Care Credit and can assist you in applying for an account if necessary. If special payment arrangements are needed, please contact our office staff prior to your appointment.
For more details, please see our Insurance and Billing page or call our office. We are happy to help you.
How long is my appointment going to take?
Typically, your first visit will take at least two hours and will consist of a complete eye examination. If treatment is required, it can usually be done the same day – this would extend the length of your appointment anywhere from 30 minutes to an hour depending on treatment required.
Retinal exam appointments take a long time relative to many other types of exams. We do our best to minimize time spent without compromising quality. Most of the time your exam can be completed within one hour.
What should I bring with me to my appointment?
Please bring with you to your appointment:
- All MEDICAL insurance information and co-pay
- Any notes given to you by your referring doctor
- A list of all medications you are taking
- Names of any other physicians you are presently seeing
- Any prescription eyewear
- Any eye drops you are currently using
- A driver if you are not comfortable driving after dilation (see below)
Can I get a prescription for glasses from your office?
No. We do not do refraction or write prescriptions for glasses. We can however make referrals to local optometrists whom we have worked with that have expertise with your specific issues.
Will my eyes be dilated?
Yes. Both eyes will be dilated for your first visit so that Dr. Narain is able to examine your retina. After your first exam, there are certain tests that you will not be dilated for; however any time that Dr. Narain examines your eyes, this will require dilation. Even if only one eye is symptomatic, it is important to dilate both eyes – 1) to compare the two and 2) to see if there are signs of the same process in the other eye.
Can I drive home after the appointment?
Because your eyes will be dilated, your vision will be affected for a while following your visit. It may be necessary for someone to drive you home after your appointment. Sunglasses are available at the front desk for your convenience.