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Vision Eye Test

Regular and comprehensive vision eye tests protect your vision by early diagnosis.  Make sure that you always see clearly.  Following is what you can expect during an eye test at McDougal Eye Center.

Visual Acuity
Visual acuity measurements evaluate how clearly each eye is seeing.  As part of the testing, you are asked to read letters on distance and near reading charts.  The results of visual acuity testing are written as a fraction, such as 20/40.

When testing distance vision, the top number in the fraction is the standard distance at which testing is done: twenty feet.  The bottom number is the smallest letter size you could read.  Normal distance visual acuity is 20/20, meaning you can read at 20 feet a letter that most human beings should be able to read at 20 feet.  If you have 20/40 visual acuity, it means you can read at 20 feet a letter that people with “normal” vision can read at 40 feet, so you have poorer vision.

Refraction Test (Eye Chart)
Refractions are the part of the eye exam during which you look through a set of lenses at an eye chart trying to determine the best view of the letters.  Using an instrument called a phoropter, the doctor places a series of lenses in front of your eyes and measures how they focus light using a hand-held lighted instrument called a retinoscope.  The doctor may also choose to use an automated instrument that automatically evaluates the focusing power of the eye. 

The power is then refined by your responses to determine the lenses that allow the clearest vision.  The result translates the data from the refraction into a prescription for either glasses or contacts that brings your eyesight to 20/20 vision – perfect vision.

The refraction test can also help to determine whether you have other eye problems, such as ulcers or infections of cornea, detached or damaged retina, macular degeneration or blockage of blood flow to the retina.

This testing may be done without the use of eye drops to determine how the eyes respond under normal seeing conditions.  In some cases, such as for patients who can’t respond verbally or when some of the eyes focusing power may be hidden, eye drops are used.  The drops temporarily keep the eyes from changing focus while testing is done.

Besides a vision test, you also need an annual eye health exam

If getting contact lenses, you will also need a contact lens exam for some special measurements. 

Patients Say:

Comprehensive testing to determine vision needs. If new glasses are not needed you are told the truth. They are not in the business to sell glasses but to give honest evaluations. — Robert B.   


Gilbert / Southern Location

Office Hours:
Monday – Friday 8am - 6pm
Extended Hours:
Wednesday until 7pm
Saturday 8am - 2pm

Closed Sundays and Major Holidays


Main / Sossaman Location

Office Hours:
Tuesday - Friday 8am - 5pm
(closed lunch 1-2pm)
Saturday 8am to 1pm

Closed Sundays, Mondays and Major Holidays