The Casa Vision eye chart screener - Near Test

ABOUT THE NEAR TEST

The Casa Vision eye chart is a tri-colored eye chart designed to detect changes in vision. This self-testing vision chart which is comprised of Snellen letters varying from 20/200 to 20/20 is used for near vision.

The background colors employed on this chart are green, red and yellow. These are the diagnostic colors involved in chromatic aberration of the eye. The relative clarity in one color with respect to the others relays information as to the visual state of the observer, hence, lending diagnostic value to the test.

Use your near prescription when using the vision chart. Testing distance is done at 16” (40cm) from the observer’s eyes. Test vision differences in one eye at a time and with both eyes open.

If the observer sees certain letters blurry in one color or more, please go see your eye doctor. The Casa Vision eye chart screener is not a substitute for regular eye exams at the eye doctor.

The undercorrected or uncorrected presbyopic patient will see the letters on the green background clearer. Certain hyperopic patients may also see the letters on the green background clearer. The overcorrected presbyopic patient will see the letters on the red background clearer (like certain overcorrected hyperopic patients). Certain myopic patients due to an overaction of accommodation for a near target may see the letters on the red background clearer. The uncorrected astigmatic patient will see the letters on the yellow background clearer.

COMMON VISION RELATED EMERGENCIES

1. If the letters are clearer in the green color, contact your eye doctor immediately if you have already been diagnosed with dry macular degeneration in the past. (Possible hyperopic shift in the early stage of the wet form of macular degeneration).
2. If the letters are clearer in the red color, there may be a progression in the cataract formation (if already been diagnosed in the past).
3. If the letters are clearer in the red color, there may be a rise in blood sugar level (diabetics).
4. In diabetic patients, a moderate amount of alcohol can cause blood sugar to rise. Excess alcohol can decrease your blood sugar level and therefore the letters may be clearer in the green color.
5. For some non-diabetic patients, excess blood alcohol can decrease the amplitude of accommodation and as a result the letters will be clearer in the green color. (Accommodation represents the focusing power of the eyes for near vision).

*Results may vary from individual to individual