ERRORS OF REFRACTION

Question 1

AMETROPIA

Answer 1

refractive error

Question 2

Eyeglasses

Answer 2

the safest and simplest way to correct a refractive error

Question 3

high index lenses

Answer 3

reduce the lens thickness and weight and are useful in correcting high refractive errors and provide comfort and better cosmetic appearance

Question 4

safety glasses or eye protectors

Answer 4

recommended for those who are involved in certain sports and hazardous activities

Question 5

shatterproof eyeglasses

Answer 5

they are recommended for those who have good vision in only one eye

Question 6

polycarbonate plastic

Answer 6

material of choice when ocular protection is the foremost consideration in making glasses as it is more impact resistant than plastic or hardened glass

Question 7

ambylopia

Answer 7

lazy eye

Question 8

sulfonamides

Answer 8

is a medication that causes the ciliary processes to swell and also the forward movement of the lens

Question 9

uncorrected hyperopia

Answer 9

frequently associated with accommodative esotropia

Question 10

concave lenses

Answer 10

the type of lenses for myopic eyes

Question 11

convex lenses

Answer 11

the type of lenses for hyperopic eyes

Question 12

refractive surgeries

Answer 12

range of procedures that is aimed at changing the refraction of the eye by altering the cornea or lens

Question 13

hypermetropia up to 4D, astigmatism up to 4D and myopia up to 12D

Answer 13

the range that LASIK surgery can correct

Question 14

250um

Answer 14

the residual bed that should remain after LASIK surgery to avoid ectasia

Question 15

ectasia

Answer 15

the bulging and thinning of the cornea

Question 16

lasik

Answer 16

the laser beam would reshape the cornea after opening a flap

Question 17

photorefractive keratectomy

Answer 17

the epithelial cells are removed with laser, which is the superficial corneal layer to the Bowman’s layer

Question 18

clear lens exchange

Answer 18

replace the natural lens of the eye with an introcular lens implant

Question 19

phakic posterior chamber implant

Answer 19

implantable contact lens is implanted behind the iris and in front of the lens

Question 20

-3D to -20.5D

Answer 20

the range that phakic posterior chamber implant can correct

Question 21

59 diopters

Answer 21

the total refractive power of the eye

Question 22

1.40

Answer 22

the refractive power of the lens

Question 23

1.38

Answer 23

the refractive power of the cornea

Question 24

myopia

Answer 24

the eyeball is too long

Question 25

myopia

Answer 25

the image is focused in front of the retina

Question 26

hyperopia

Answer 26

the eyeball is short

Question 27

hyperopia

Answer 27

the image is focused at the back of the retina

Question 28

astigmatism

Answer 28

there is an irregular curvature of the eyeball

Question 29

presbyopia

Answer 29

there is a loss of accommodation of the lens due to it being hardened

Question 30

more than -6 diopters

Answer 30

meaning of high myopia in which the axial length is usually greater than 26 mm

Question 31

pathological or degenerative myopia

Answer 31

progressive anteroposterior elongation of the scleral envelop associated with range of secondary ocular changes

Question 32

Amblyopia

Answer 32

Is the unilateral, or rarely bilateral, decrease in best corrected visual acuity (VA) caused by form vision deprivation and/or abnormal binocular interaction, for which there is no identifiable pathology of the eye or visual pathway.

Question 33

Strabismic amblyopia

Answer 33

results from abnormal binocular interaction where there is continued monocular suppression of the deviating eye.

Question 34

Anisometropic amblyopia

Answer 34

is caused by a difference in refractive error between the eyes and may result from a difference of as little as 1 dioptre. it is frequently associated with microstrabismus and may co-exist with strabismic amblyopia

Question 35

Stimulus deprivation amblyopia

Answer 35

Results from vision deprivation. It may be unilateral or bilateral and is typically caused by opacities in the media (e.g. cataract) or ptosis that covers the pupil.

Question 36

Bilateral ametropic amblyopia

Answer 36

Results from high symmetrical refractive errors, usually hypermetropia.

Question 37

Meridional amblyopia

Answer 37

Results from image blur in one meridian. It can be unilateral or bilateral and is caused by uncorrected astigmatism (usually >1 D) persisting beyond the period of emmetropization in early childhood.

Question 38

crowding phenomenon

Answer 38

The phenomenon where VA in amblyopia is usually better when reading single letters than letters in a row.

Question 39

A difference in best-corrected VA of two Snellen lines or more (or >1 log unit)

Answer 39

Is indicative of amblyopia.

Question 40

7–8 years

Answer 40

The sensitive period during which the acuity of an amblyopic eye can be improved is usually up to ___ years in strabismic amblyopia

Question 41

occlusion of the normal eye

Answer 41

most effective treatment for amblyopia

Question 42

6 months

Answer 42

how long should occlusion of the normal eye as treatment take

Question 43

penalization

Answer 43

the vision of the normal eye is blurred with atropine and works best with mild-moderate amblyopia