Procedure for Distance vision:
• Illumination should be adequate ( 100 foot candles)
• Customer is asked to sit comfortably at a 6 meter distance from the vision chart.
• Check the vision one eye (Uniocular) at a time, with the other eye fully occluded.
• Use a trial frame with occluder preferably if the customer does not have a PGP (or take care that the customer does not press the occluded eye with his fingers).
• Check the worst eye first.
• Check vision with the glasses (the recent one or which the customer uses regularly).
• Comment on the quality of vision as the customer reports.
• Observe the customer while checking vision. (Face turn, head tilts, chin position, squeezing of eyes)
• Comment on the customer’s response. ( Speed of response, missing alphabets, co-operation of customer)
• Customer is asked to read from the top letter Vision is taken as 6/60, 6/36, 6/24…. -Numerator indicates distance at which person is. - Denominator indicates distance at which person with normal vision able to read that letter
• If one cannot see the top line from 6 meter, customer is slowly asked to move towards the chart till one can read the top line.
• Vision is recorded as 5/60, 4/60, 3/60, 2/60 & 1/60
• If customer is unable to read even from 1 m he/she is asked to count fingers of examiner.
• Vision is recorded as CF-3m, CF-2m, CF- 1m & CF close to face.
• If customer cannot count fingers close to face then examiner moves his hand close to the customers face
• If customer can appreciate the hand movements (HM) VA is recorded as HM close to face.
• If customer cannot appreciate HM, then taken to a dark room and asked to close one eye firmly with palm and look straight.
• Light is thrown on the open eye from all directions i.e. up, down, nasal &temporal.
• If customer can recognize the light and indicate its direction then visual acuity is recorded as PL + & PR + is all 4 quadrants.
• If customer is not able to perceive light from a particular quadrant then negative sign is put against that quadrant and is said to have faulty PR.
• If customer can see the glow of light but cannot indicate the side of projected rays then vision is recorded as only PL with no PR.
• If customer cannot perceive any glow vision is recorded as No PL.
Order of testing vision
• Vision at 6 meters …….. if less
• Vision at 3 meters ……… if less, take the chart closer
• Counting fingers at 1 meter ……. If less
• Counting fingers close to face …….. if less
• Hand movements close to face……..if less
• Perception of light (PL) and Projection of rays (PR) in different quadrants.
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