Glasses prescription Visual acuity OD -1.00 / -0.25 X 90 6/6 OS Plano HM

OD OS K1 43.50 43.20 K2 44.00 44.00 AL 23.12 23.20 Lens calculation for OS A constant 118.00 IOL Ref 20.00 0.66 20.50 0.31 21.00 -0.05 21.50 -0.41 22.00 -0.78

The above biometry belongs to a 45 year-old man who is about to undergo left eye operation with lens implant.

a. What does the left A-scan show?

You decide to implant a 21.50D with A constant 118.00. However, on the day of the operation, you run out of lenses with 118.00 instead you are given a 21.50 with A constant of 118.50.

b. What would be the post-operative refraction from what you have 
    predicted? (more or less myopic)

 

Answer aThe left eye is aphakic. 
Note that the A scan has only two spikes whereas the right eye has four spikes.
 

Answer bThe refraction will be less myopic than expected.