Question

short note on construction of Snellen's chart ( 5 marks ) ​

Answer 1

Answer:

The Snellen chart is a collection of letters of ever decreasing size from top to bottom. There is number below each letter and with the patient standing at six meters (this forms the numerator). The uncovered eye is formally tested by asking the patient to read the smallest series of letters. This forms the denominator.

Normal vision is thus charted thus:

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6/6 vision the chart line with “6” under it

•

6/24 would indicate that at six meters the larger letter with “24” under it would be all that could be read

If no letters can be read then:

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Counting fingers (CF)

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Hand movements (HM)

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Perception of light (PL)

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No perception of light (NPL)