Anisometropia

Question 1

What is anisometropia

Answer 1

Unequal refractive state between the 2 eyes, occurring in one or both principal meridians

> 1.00 D

Question 2

When can anisometropia lead to problems?

Answer 2

When corrected or uncorrected

Question 3

What happens when anisometropia is uncorrected

Answer 3

Results in the inhabits to have sharply focused images on the retinas of both eyes simultaneously

Which may lead to suppression or amblyopia

Question 4

What is amblyopia

Answer 4

Unilateral or bilateral condition where BCVA is poorer than 20/20 in the absence of any structural anomalies or ocular disease

Question 5

What occurs if anisometropia is corrected?

Answer 5

Differential Prism imbalance

Question 6

What is prism imbalance?

Answer 6

Any movement of visual axes away from the OCs can lead to prismatic imbalance according to prentices

Problems occur as a result of differential prismatic effects, horizontal and/or vertical

Question 7

Horizontal prismatic effects seldom(rarely) causes problems for the anisometrope because

Answer 7

the visual system is capable of reasonably large amplitude horizontal fusional vergence movements

Question 8

What type of vergence allow anisometropes to work through horizontal prismatic effects?

Answer 8

Positive & negative fusional vergence

Question 9

Vertical prismatic effects are most likely a problem when

Answer 9

Visual axes are lowered for reading

When a corrected anisometrope lowers theirs eyes to read through an add

Question 10

Why is vertical imbalance more often in anisometropes than horizontal

Answer 10

Because our eyes have limited capability of vertical fusional movements

Question 11

Why do not all anisometropic MF users excperience vertical imbalance?

Answer 11

Tolerances vary

Question 12

When do anisometropes experience vertical prismatic effects?

Answer 12

some are symptomatic when they’re >1,50D difference in vertical meridians of each lens especially recent onset

Question 13

Vertical imbalance is especially a probles if recent onset and unilateral. For ex:

Answer 13

Cataract surgery
Trauma/surgery
Retinal surgery/disease
(Scleral buckle)

Question 14

To determine if vertical imbalance will be a problem, you can ask pt to read and observe them

Answer 14

1. If they’re drop their eyes only, they wont need compensation
2. If they lower head, they are reading through the OC to prevent the vertical imbalance and will probably experience difficult in MF