Stenopaic Slit 2

Question 1

What are the standard subjective refraction procedures?

Answer 1

Astigmatic Dials
Crossed Cylinders
Stenopaic Slit
Fogging methods
Biochrome and accommodation balance techniques

Question 2

What are the binocular subjective refraction procdures?

Answer 2

Turville infinity balance
Vectograph Polaroid Techniques

Question 3

What is the general slit procedure?

What can it be performed in?

Answer 3

Pt or Dr rotates slit until to best position which occurs when the slit if perpendicular to the major focal line

Can be used on a trial frame with lenses

Question 4

What happens if the slit is hoirzontal?

Answer 4

The vertical rays are restricted

Question 5

What gives the pt the best vision?

Answer 5

When the small VFL is on the retina which means that horizontal median is corrected

Question 6

What is the stenopaic Slit procedure?

Answer 6

1. Occlude the eye not being tested
2. Find Best sphere
3. Add additional +0.75D to best sphere in order to move the COLC in front of the retina
4. Introduce the slit and have pt rotate the slit to find the best potion that gives the best VA
   Note: Orientation of slit
5. With slit in position add +/- spheres in front of the slit (and previous best sphere lenses) to determine the max plus (minimum minus) sphere that give optimum VA for that slit
6. Rotate the slit 90 and add +/- spheres to determine the max plus sphere that gives the best VA
7. Two powers = Refractive correction

Question 7

How many times are you performing best sphere?

Answer 7

3x!!

1. With out slit
2. With slit at preferred meridian
3. 90 away from preferred meridian