Keratometry

Question 1

Keratometry

Answer 1

First produced by B&L in late 1920s/early 1930s
- Measures central anterior curvature of the cornea, 3mm
- Detects corneal astigmatism
- Provides dioptric power of steepest and flattest meridian
- Detects irregular/oblique astigmatism

Question 2

Uses of keratometer

Answer 2

1. Fitting and eval of CLa
2. Determines K’s prior to IOL surgery
3. Determines cause of refractive error
4. Assesses changes in cornea shape
5. Starting point/baseline for refraction
6. Evaluates distortion or irregularity
   MCAR=Mires clear and regular

Question 3

Keratometry readings

Answer 3

Difference between horizontal and vertical is corneal astig
- Allows you to find with the rule or against
* If flatter curve is in the horizontal meridian it is recorded as with the rule *

Question 4

Advantages of keratometry (Good for pts with)

Answer 4

Good for pts with:
1. Poor fixation
2. Corneal abnormalities
3. Distorted mires
4. Corneal dryness

Provides clear understanding of integrity of precorneal tear film, a dynamic view of the surface of the cornea

Question 5

Conversion of diopters to radians

Answer 5

Use flatter meridian
D=1.3375(index)-1.00/R(radius)
or D=0.3375/R (in meters)
Ex: 0.3375/42.00D= 8.03mm BC
Add 1mm for soft lens