Page 46 - The Book Pi in eye

Rajesh Khanna, MD

is calculated based on data obtained from the eye.

Calculations:
The ophthalmologist will use all of these measurements to
determine the best power of intraocular lens (IOL). Once the three
variables are obtained, there a few mathematical formulas employed
to generate the lens power. These are Hoffer Q for eyes smaller than
22mm, and SRKT is good for eyes between 22-26 mm. Holladay 2
and Haigis can be used for a variety of ranges, but requires more data
and customizations. A good surgeon may compare calculation results
with different formulas.
The surgeon can further refine his/her results based on the
outcome of previous results. Calculations after previous eye surgery
are tougher as the assumptions made in the formula are changed.
Furthermore, after previous Lasik, the relationship between anterior
and posterior cornea is changed. RK interferes in corneal power
detection as well. Special formulas are required on these special cases.

Summary of a good consultation:

1. Review of medical and visual history
2. Check vision, refraction, and auto refraction
3. Corneal topography to analyze shape of the eye
4. Pachymetry to measure the thickness of the cornea
5. Slit lamp: to observe tear film and cornea and lens
6. Intraocular pressure to rule out glaucoma
7. Dilated exam to rule out pathologies like diabetes,
hypertension, glaucoma, and macular degeneration
8. Axial length measurement of the eye
9. Explanation on eye model, visual charts
10. Get chance to talk to surgeon
11. Patient Testimonials: Important to read, will verify the
doctors intelligence and proficiency
12. Optional tests, OCT, CST, Visual field

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