Oc anatomy

Question 1

Avg corneal 1) central 2) peripheral thickness?

Answer 1

1) 500-550microns centrally, 2) 660 peri

Question 2

Avg HVID?

Answer 2

11.7mm (vertical usually smaller, ~9-11)

Question 3

palpebral aperture ht important for determining which CL fitting characteristic?

Answer 3

LD - lens diameter (NOT HVID?)

Question 4

low upper lid - good for ____ fits
high upper lid - good for ____ fits
high lower lid - decrease ___
low lower lid - poor candidate for which lens type?

Answer 4

lid attachment
interpalpebral
LD
rigid bifocal (requires inf. lid support)

Question 5

how is lid tension determined?

-tight lids have what effect? Loose lids?

Answer 5

lid eversion
tight - pull lens UP OR squeeze it down (watermelon)
loose - push lens down

Question 6

normal blink rate/minute?

-help determine which lens ___ to use

Answer 6

10-15/min

-material (based on rate/completeness of blink)

Question 7

pupil dia - measure in bright or dim?

• what aspect of CL fitting does it determine?
• effects of smaller OZD?

Answer 7

dim
OZD
smaller OZD = more glare/flare @ night (when pupil dilated)

-also important in bifocals, ortho-K, refractive surgery