Exams and Tests

During the eye examination, the ophthalmologist performs the following tests:

• Visual acuity, which is the level of detail a person can see, is checked. If the patient's visual acuity is not 20/20, testing may include refraction to determine if glasses will improve vision.
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• The patient's visual field, which is the area (or "field") in which a person can see other people and objects, is also checked.
  
  
• The front of each eye is examined using a special microscope, called a slit lamp, to check for cataracts.
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• Tonometry is a method used to measure the pressure inside the eye. If the pressure is increased, it may indicate glaucoma.
  
  
  • If signs of glaucoma are noted, a formal, computerized visual field examination may be performed.
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  • Visual field testing checks the peripheral (or side) vision, typically by using an automated visual field machine. This test is done to rule out any visual field defects due to glaucoma.
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• The ophthalmologist examines the patient's retina to check for diabetic retinopathy; this requires dilation of the pupils with eye drops to ensure an adequate examination of the retina.
  
  
  • If significant signs of diabetic retinopathy are noted, a fluorescein angiogram may be done to help show the extent of damage done to the retinal blood vessels and to help guide treatment.
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  • During a fluorescein angiogram, a yellow dye is injected into the blood vessels of the hand or the arm; this dye travels all over the body through the blood vessels, and film or digital photographs are taken as the dye travels through the blood vessels in the retina.
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  • Where the blood vessels in the retina are damaged, the dye leaks out of the blood vessels. This leakage and its location are shown on the photographs.