Reading up close

Question 1

threats to vision in wet AMD

Answer 1

sub retinal heme
subRPE heme
sub retinal detachment
subRPE detachment (PED)

Question 2

if someone is a smoker, what is there likelihood of recurrence of a CNVM?

Answer 2

1.7-2.2x more likely

Question 3

what magnification is required in a telescope in order for the patient to watch TV with 20/40 print?

BCVA dist

• OD: 20/120
• OS: 20/120

SUBJ

• OD: +1.00Ds
• OS: +1.00Ds

Answer 3

3x
want/need
120/40=3x

Question 4

the pt is Red +6.00D readers. How much BI prism is required

Answer 4

8 BI each eye

Question 5

what M print size represents standard newspaper print size?

Answer 5

1M

Question 6

this patient can read 4M letters on the Lighthouse near card at a test distance of 40cm. How is the near VA recorded by convention?

Answer 6

.4m/4M

Question 7

that patient moves the near acuity card to a test distance of 10cm. what print size should he be able to read at this distance?

Answer 7

1M
RDM

Dold/Dnew=.4/.1=4x larger

Question 8

the patient was shown a CCTV to help him read his mail. what type of magnification is this?

Answer 8

Relative size magnification

Question 9

how much mag is provided by a +12D HHM when it is used as a collimating magnifier at a distance of 25cm

Answer 9

3x

M=Fd
M=(12D)(.25)=3x

Question 10

prism and high add powers

Answer 10

high plus readers with a power off +4D or higher require BI prism bc the high plus lenses result in a high convergence demand at near. The required amount of prism PER EYE is the dioptric power of the lens plus 2

Question 11

11M subtends ___arcminutes at one meter

Answer 11

5

Question 12

1M= what snellen

Answer 12

20/20 at 1m

20/50 at 40cm (newspaper size)

Question 13

E on the 20/20 line

Answer 13

subtends 5 arc minutes, has 5 components, thus, each line within the E subtends 1 arc minute at 1 meter

Question 14

1M at near

Answer 14

when a 1M letter is viewed at 40cm, the acuity will decrease by a factor of 2.5X because the distance has decreased by 2.5X (1m/0.4m). Thus, reading a 1M letter at 40cm requires a MAR of 2.5, which is appx the same as 20/50 vision (20 x 2.5=50)

Question 15

relative size magnification

Answer 15

due to the change in actual size of the object WITHOUT a change in the distance of the object from the patient
-a CCTV, large print book, enlarging reading material with a copier are examples

Question 16

best reading option for someone with advanced visual impairment

Answer 16

CCTV

Question 17

collimating magnifier

Answer 17

when a plus lens is positioned so that the object that is being viewed is located at the primary focal point of the lens, and parallel like leaves the lens. the magnification of a collimating (often HHM) magnifier is give by M=Fd

DOES NOT need an add or accommodation

Question 18

non-collimating magnifier

Answer 18

stand magnifier
-the object is inside the focal length of the lens, resulting in divergent light leaving the lens. The patient must accommodate or use an add in order to see the object clearly. The max magnification provided by a stand magnifier is a combination of the original mag of the lens + additional mag provided by accommodation, resulting in the equation M=F/4 +1

this is sometimes called conventional mag

Need an Add or accommodation