For a patient history we will need a list of medications taken and occupational or environmental conditions that may be affecting vision. The doctor or her staff will ask about any eye or vision problems you may be having and about your overall health. You will also be asked about any previous eye or health conditions of you and your family members.
Visual acuity measurements evaluate how clearly each eye is seeing. During testing, you are asked to read letters on distance and near reading charts.
When testing distance vision, the top number in the fraction is the distance at which testing is done, twenty feet. The bottom number is the size of the letter you were able to read. A person with 20/40 vision would have to be at 20 feet in order to see what should be seen at 40 feet. Normal distance visual acuity is 20/20.
A refraction is done using a phoropter to determine the prescription needed to compensate for any refractive error (nearsightedness, farsightedness, or astigmatism). Some preliminary testing may be done using an automated refractor (computer) that evaluates your prescription first and then is refined by the doctor using the phoropter.
External examination of the eye includes evaluation of the cornea, eyelids, conjunctiva and surrounding eye tissue using bright light and magnification.
Evaluation of the lens, retina and posterior section of the eye may be done through a dilated pupil to provide a better view of the internal structures of the eye.
Measurement of pressure within the eye (tonometry) is performed. Normal eye pressures range from 10 to 21 millimeters of mercury (mm Hg), averaging about 14 to 16 mm Hg. Today we now know that measuring the eye pressure is only one part of checking for glaucoma. The optic nerve must be evaluated too. We now know that the corneal thickness influences the measurements and if any part of this evaluation is suspect for glaucoma you will be referred for further testing by an Ophthalmologist.
If you have questions regarding any eye or vision conditions diagnosed, or treatment recommended, don’t hesitate to ask for additional information or explanation from the doctor.