What You Should Know About Eye Exams

 Wondering what to expect during your exam?  To check for vision problems and eye disorders, the doctor may use  bright lights, instruments, an array of lenses, special eye drops, and  other techniques:

Visual Acuity Test: To measure  how clearly you see at a distance, you identify letters of various  sizes on a printed chart, typically positioned 20 feet away.  Or you may  view a chart inside a machine.  The type gets smaller as you move down  its rows.  You’ll cover one eye, then the other, as you read the letters  aloud.  Your score will then be compared to how someone with normal  vision sees at that distance.

Refraction Assessment: If  your eyesight isn’t perfect, this test helps your doctor determine the  right prescription for glasses or contact lenses.  You look into a  mask-like device called a Phoroptor, which holds lenses of various  strengths.  As you focus on an eye chart, your doctor will flip two  lenses into your view and ask it the letters are more or less clear.  By  repeating this step with different combinations, the doctor can  pinpoint the power that gives you the best possible vision.  If you  currently wear glasses or contacts, the doctor will check to see whether  your prescription has changed.

Pupil Size and Reactivity Test: The  doctor shines a light into each eye to see whether both pupils are the  same size and contract normally.  Pupil problems can be a warning sign  of such disorders as high blood pressure, multiple sclerosis, or  glaucoma. 

 Eye Movement Exam: You  track a moving target, such as the doctor’s hand or a pen.  As your eyes  travel up and down, and from side to side, the doctor checks whether  they are properly aligned.  This test screens for strabismus - a  disorder in which the eyes don’t move together when focusing on an  object-and other eye movement disorders.

Visual Field Exam: There  are several ways to test your peripheral (side) vision, but they all  involve covering one eye and staring straight ahead with the other.  In  the most basic test, your doctor moves his hand through your field of  vision, and asks if you can see how many fingers he’s holding up.  Or  you may watch a screen as dots if light flash.  Usually, you’ll press a  button each time you see a dot, enabling a computer to map your field of  vision.  The test detects blind spots due to glaucoma, a stroke, or  other ailments.

Slit Lamp Exam: A slit lamp is a  microscope with a thin beam of light, used to examine the front of each  eye, including your iris (colored portion), sclera (white area),  eyelid, lens, and cornea, under magnification. The doctor may use  special eye drops to dilate (expand) your pupils, then repeat the exam,  to view the retina and back of the eye.  The test checks for cataracts,  macular degeneration, diabetes complications, cornea scratches or  infections, and chronic dry eye.  The eye drops take about 15 minutes to  work and may sting briefly.  You might notice a medicinal taste in your  mouth as the drops drain from your tear ducts into your throat.  After  the exam, your eyes will be more sensitive to light for a few hours,  until the dilating drops wear off. 

 Schirmer Tear Test: To  gauge the moistness of your eyes, the doctor can place extremely thin  strips of blotting paper under your lower eyelids.  It doesn’t hurt.   After five minutes, the doctor checks how much of the strip is saturated  with tears.  

Glaucoma Test: Also known  as tonometry, this test gauges the pressure inside your eyes, which goes  up if you have glaucoma.  First, the doctor uses special eye drops to  numb your eyes.  He may also add a squirt of orange dye to make it  easier to view your cornea.  Using a little probe on the slit lamp, he  gently presses on each cornea to measure eye pressure.  It doesn’t hurt,  and the numbing drops wear off in about 20 minutes. 

Getting the results

 After your exam is over, the doctor will  go over the findings with you, alert you to any risks, and suggest steps  to protect your vision, which could be as simple as having another  checkup in one or more years.  If your current glasses or contacts  aren’t doing the trick anymore, you’ll get a prescription for new ones.   If other eye problems are detected, your doctor will explain treatment  options, which may include eye drops, medication, or other therapies.

What  if your previously perfect vision isn’t what it used to be?  If the  problem is mild-you can still pass the driver’s eye test, read  comfortably, and safely perform everyday tasks-you may decide not to get  corrective lenses yet.  But if it’s impairing you even moderately, then  it’s time for glasses or contacts.  Don’t like those solutions?  Ask if  you’re a candidate for laser surgery to reshape your cornea, which can  enhance your vision.