CLINICAL TECHNIQUES - VOLK Lenses and Slit lamp

Question 1

What is the neutral density filter on the slit lamp complemented by?

Answer 1

The rheostat on the instrument

Question 2

What is the red free (green) filter used for?

Answer 2

Enhances contrast of blood vessels on the retina.
Enhances view of nerve fibre layer.

Question 3

How far should AMSLER chart be? How many degrees is the visual field for fixation for an AMSLER chart?

Answer 3

33cm
20 degrees (central 10 degrees)

Question 4

Why should the pupil not be dilated in AMSLER grid testing?

Answer 4

Avoid photostress effect.

Question 5

How wide is the field of view in colour fundus photography?

Answer 5

30-35 degrees

Question 6

What does autoflouresence refer to?

Answer 6

Emission of intrinsic flouresence by substance subsequent to stimulation by excitation energy

Question 7

What is the source of autoflouresence?

Answer 7

Lipofuscin in the RPE is source of backgroudn autofloureseence of retina –> byproduct of phagocytosis of outer segments in the RPE.