The eye is a beautiful organ, and it is the only place in the human body where a doctor can see a part of the central nervous system, the optic nerve. The observation of that nerve is a crucial part of a comprehensive eye examination. Both the dilated and the undilated eye exams provide important information to an eye doctor. Let s explore the undilated exam first. The Undilated Eye Exam One of the first parts of a comprehensive eye exam is a test of your vision, and perhaps a measurement to determine an eyeglass prescription, both of which require that your eyes remain undilated. In addition, eye doctors will examine your
responses to light prior to dilation. This can be important for determining whether the visual pathways for each eye are functioning properly. There is also an examination, called gonioscopy, which allows the doctor to examine your eye s drainage angle with a special mirrored lens. The angle that is being referred to is the angle between the iris, which makes up the colored part of your eye, and the cornea, which is the clear window front part of your eye. When the angle is open, your ophthalmologist can see most, if not all, of your eye s drainage system. When the angle is narrow, only portions of the drainage angle are visible, and in acute angle-closure glaucoma, none of it is visible.
Part of a glaucoma examination is formal visual field testing, where your peripheral, or side vision, is tested. Ideally, your eyes are not dilated during this test. Finally, there are other parts of the front of the eye, the iris for example, which should be examined when your eyes are not dilated. The Dilated Eye Exam The view to the back of the eye is limited when the pupil is not dilated. When your pupil is small, an eye doctor can see your but the view is limited. In order to see the entire retina, the pupil must be dilated. This is achieved through the use of eye drops. They typically take about 15-30 minutes to fully dilate the pupils, depending the person s response to the medication, and typically take 4-6 hours to wear off. Onc your eyes are dilated, there is an increase in light sensitivity because the pupil is large and more light is coming through, so bring your sunglasses, or your ophthalmologist may provide some disposable shades for your use. You may also experience blurry vision, particularly if you are trying to read. Some patients feel a tightening or different sensation in their eyelids. If it is your first time having your eyes dilated or you know your vision is too impaired for driving after dilation, bring a friend or companion to drive you home from your examination.
While in the past there were some eye drops that could reverse the dilation, these are no longer available, so you will have to wait the 4-6 hours before the drops completely wear off. What Conditions are Diagnosed with a Dilated Eye Exam? Glaucoma The optic nerve can be seen through an undilated pupil, but for optimum viewing a dilated pupil is required. This is important for the diagnosis of, as well as other diseases of the optic nerve. Macular Degeneration Two very common retinal diseases, diabetic retinopathy and (AMD), are diagnosed and monitored by examining the retina through a dilated pupil. Other Conditions In addition to macular degeneration and glaucoma, there are many other conditions that require pupil dilation, such as detection of a retinal tear or detachment, or an ocular tumor, just to name a few. How Frequently Should You Have a Comprehensive Dilated Eye Exam? The National Eye Institute generally recommends that starting at age 60 everyone should have an annual, comprehensive, dilated eye examination. If you are African-American, the recommended age of having a dilated eye exam is 40 years old, because of the higher risk of glaucoma.
The American Academy of Ophthalmology has specific recommendations for diabetic patients. It is recommended that Type 1 diabetics have their first eye exam within five years of diagnosis. Type 2 diabetics, should have their eye exam at the time of diagnosis. If you are a diabetic woman considering pregnancy, it is recommended to have an exam prior to conception or early in the first trimester. Summary As part of a comprehensive eye examination, pupil dilation is very important at revealing the status of your optic nerve and retina, and is critical to preventing and treating eye conditions that could potentially lead to vision loss. Whether eye dilation during an exam is necessary depends on the reason for your exam, your age, your overall health and your risk of eye diseases. The eye drops used for dilation cause your pupils to widen, allowing in more light and giving your doctor a better view of the back of your eye. Eye dilation assists your doctor in diagnosing common diseases and conditions, possibly at their earliest stages. They include: Eye dilation also makes your vision blurry and your eyes more light sensitive, which, for a few hours, can affect your ability to drive or work.
So if eye dilation is greatly inconvenient, ask your doctor about arranging another appointment. Alternatives to dilation are available, but they aren\’t as effective for allowing a careful examination of the back of your eye. In determining whether eye dilation is necessary for you, your eye doctor may consider: Your age. The risk of eye diseases increases with age. The National Institutes of Health (NIH) recommends a yearly dilated eye exam if you\’re 60 or older. Your ethnic background. Some ethnic backgrounds are at increased risk of certain eye diseases. African-Americans and Hispanics, who are at increased risk of glaucoma, are advised to have a dilated eye exam every one to two years, starting at age 40. Your eye health. Having a history of eye diseases that affect the back of the eye, such as retinal detachment, may increase your risk of future eye problems. Your overall health. Certain diseases, such as diabetes, increase the risk of eye disease. The reason you are seeking an eye evaluation. Certain symptoms may require a dilated examination to determine the cause. Some conditions requiring follow-up examinations may not need dilation at every visit unless there are new symptoms or concerns. Feb. 07, 2018