Snellen Chart numbers Sphere

Question 1

6/6

Answer 1

sphere 0.25 cyl 0.50

Question 2

6/9

Answer 2

sphere 0.50 cyl 1.00

Question 3

6/12

Answer 3

sphere 0.75 cyl 1.50

Question 4

6/18

Answer 4

sphere 1.00 cyl 2.00

Question 5

6/24

Answer 5

sphere 1.25 cyl 2.50

Question 6

6/36

Answer 6

sphere 1.75 cyl 3.50

Question 7

6/60

Answer 7

sphere 2.50 cyl 5.00

Question 8

3/36

Answer 8

sphere 3.00 cyl 6.00

Question 9

3/60

Answer 9

sphere 4.00 cyl 8.00

Question 10

1/24

Answer 10

sphere 4.50 cyl 9.00

Question 11

1/36

Answer 11

sphere 5.75 cyl 11.50

Question 12

1/60

Answer 12

sphere 7.50 cyl 15.00

Question 13

Anisha is 20 years old, and has a prescription of -3.00 DS and pinhole
acuity of 6/6
* What is her vision likely to be recorded as?
Her optometrist found a retinoscopy result of -2.50 DS
* What acuity is she likely to achieve with this result?
A second optometrist found a result of -3.50 DS
* What acuity is she likely to achieve now?

Answer 13

has a prescription of -3.00 DS and
pinhole acuity of 6/6 she was uncorrecgted -3.00D so in image formed in the front of the retina estimated vision: 3/36
retinoscopy result of -2.50 DS. she was undercorrested by -0.50DS image still formed in front of retina but closer to the fovea estimated VA: 6/9
found a result of -3.50 DS overcorrested by -0.50 image formed behind the retina estimates VA: 6/6 as younger patient can accomodate

Question 14

Rob is 25 years old and has a refractive error of +6.00 DS
* What is his vision likely to be?
retinoscopy result of +5.00 DS what is his VA likely to be??
retinoscopy result of +7.00 DS
What is his acuity likely to be?

Answer 14

ref error of +6.00 which patient was uncorrected by image forms behind the retina estimated VA worse that 6/6 due to high hyperopia
ret of +5.00 undercorrected by +1.00DS image formed behind retina w this lens estimated VA: 6/6 as patient can accommodate +1DS
ret of +7.00DS overcorrected by +1.00DS image is formed in front of the retina w this lens due to overcorrection by 1 so estimated VA: 6/18

Question 15

Elaine is 60 years old and has a refractive error of -3.00
DS and pinhole acuity of 6/6
What is his vision likely to be?
retinoscopy result of -2.50 DS
* What acuity is she likely to achieve with this result?
found a result of -3.50 DS What acuity is she likely to achieve now?

Answer 15

patient uncorrected by -3.00DS the image will form in front of the retina estimated VA: 3/36
patient undercorrected by -0.50DS image will form in front of retina estimated VA: 6/9
patient was overcorrected by -0.50 of image will form behind the retina estiamted VA: 6/9 as older patients cant accommodate

Question 16

Lesley is 22 has a prescription of -4.00DS and a pinhole acuity of 6/6 the optom put a -3.00DS in front of her eye what level of scuiy is she likely to acheive?

Answer 16

corrected by -1.00DS so 6/18

Question 17

you have refrqacted a patient and found that the best sphere is -1.50 DS however patient has VA of 6/9 and u find that their acuity improves to 6/6 w/ a pinhole. what is the estimated amnt of uncorrected cyl power??

Answer 17

patients VA is 6/9 so cyl is -1.00DC