Scleral Lenses (M2)

Question 1

What are the three zones that make up a scleral lens?

Answer 1

1. optic zone
2. transition zone
3. landing (haptic) zone

Question 2

What are the indications for scleral lenses?

Answer 2

1. correction of corneal induced refractive error
2. regular corneal astigmatism
3. irregular corneal astigmatism
4. corneal ectasia

Question 3

What are examples of corneal ectasia?

Answer 3

1. keratoconus
2. Pellucids marginal degeneration
3. keratoglobus

Question 4

What are the advantages of the scleral lens over the corneal lens?

Answer 4

1. improved patient comfort
2. more stable vision
3. less chance of lens dislodge
4. easier fit

Question 5

What are the disadvantages of the scleral lens compared to the corneal lens?

Answer 5

1. large lens
2. need for non preserved saline
3. fitting sclera
4. requires fit set
5. cost of lens high

Question 6

What is the height that is important when determining a scleral lens?

Answer 6

height difference from 10mm chord to 15mm chord

Question 7

What is the method to select the initial lens for the scleral Jupiter lens?

Answer 7

1.00D steeper than steep cornea to obtain vault, then flatten BC until almost touches cornea

Question 8

What is the method to select the initial lens for the scleral msd lens?

Answer 8

select recommended sag lens based on steep K’s

Question 9

What are the adjustment parameters that can be altered?

Answer 9

1. mid peripheral curve to fit cornea and limbus
2. edge clearance to align on sclera
3. toric edge curves available
4. fenestration (to help with removal) available but not recommended

Question 10

How much does a 100 micron change in sag height alter power of tear lens?

Answer 10

0.12D added

Question 11

What is done to evaluate the lens fit of a scleral lens?

Answer 11

1. NaFl pattern
2. optic section to observe lens surface, tear reservoir layer, and corneal thickness
3. observe central and limbal vault
4. evaluate conjunctival impingement and blanching
5. let settle for 10 to 15 min

Question 12

What should be filled in the scleral lens when inserting?

Answer 12

non preserved saline (unisol 4)

Question 13

What change is made to decrease blanching in scleral lenses?

Answer 13

flatten edge lift

Question 14

When an edge is flattened, what happens to the overall sag depth of lens?

Answer 14

decreases

Question 15

If a patient has an oblate shaped cornea due to post refractive corneal surgery, what should the initial scleral lens be?

Answer 15

4.40 sag lens with increased profile

Question 16

What is it called when loose conj travels into limbal vault area of the lens?

Answer 16

conjunctival prolapse, hooding, or chalasis