Supplemental Skills

Question 1

Common error with measuring axial length (A-scan)

Answer 1

short axial length due to compression of the cornea with contact A-scan ultrasonography

Question 2

Information needed to calculate power of an intraocular lens

Answer 2

• corneal curvature
• axial length
• lens manufacturer’s A constant

Question 3

Anterior chamber depth

Answer 3

• may affect IOP
• can be compressed when a contact A-scan probe is used
• often shallower in a pt w/nuclear sclerotic cataracts

Question 4

What is minimal tear-film breakup time considered normal?

Answer 4

10 sconds

Question 5

Most pts tested for glare sensitivity with the brightness acuity test (BAT) have significant decrease in vision at what light intensity?

Answer 5

Medium

Question 6

What is the average axial length of the human eye?

Answer 6

23.00 to 23.50 mm

Question 7

Schirmer test

Answer 7

measures basal tear production

Question 8

What is average corneal curvature of human eye?

Answer 8

43.00 mm

Question 9

What makes an eye more myopic?

Answer 9

• longer eye (<43.00 mm)

* image of an object focuses in front of the retina

Question 10

Farnsworth-Munsell D-15

Answer 10

• tests color vision

* consists of 15 pated-colored chips of similar brightness must be arranged by pt in a specific color sequence

Question 11

OCT measures

Answer 11

central retinal thickness

Question 12

Thick cornea IOP will be:

Answer 12

falsely high

Question 13

Thin cornea IOP will be:

Answer 13

falsely low

Question 14

Increased corneal thickness is commonly associated with:

Answer 14

abnormalities of the corneal endothelial cells

Question 15

Normal tear production for Schirmer test with topical anesthetic (Schirmer II)

Answer 15

more than 10 mm in 5 minutes

Question 16

Phenol red thread test measures

Answer 16

• tear output

* similar to schirmer test

Question 17

Gonioscopy

Answer 17

examines angle structure of the eye

Question 18

Glare testing

Answer 18

most useful in evaluation of cataract

Question 19

What is the normal thickness of the central cornea

Answer 19

0.56 to 0.58 mm

Question 20

What will result from a 1-mm error in axial length

Answer 20

approximately 3 D of change in postoperative refractive error

Question 21

How do you measure if pt has abnormal tear-film breakup?

Answer 21

• stain tears with fluorescein
• ask pt not to blink
• record when blue patches appear