kane2
I refer to the following article:
April 2020, Ophthalmology. 127(8)
Jack X Kane et al
Purpose: To assess the accuracy of intraocular lens (IOL) power formulas modified specifically for patients with keratoconus (Holladay 2 with keratoconus adjustment and Kane keratoconus formula) compared with normal IOL power formulas (Barrett Universal 2, Haigis, Hoffer Q, Holladay 1, Holladay 2, Kane, and SRK/T).
Design: Retrospective consecutive case series.
Participants: A total of 147 eyes of 147 patients with keratoconus.
Methods: Data from patients with keratoconus who had preoperative IOLMaster biometry were included. A single eye per qualifying patient was randomly selected. The predicted refraction was calculated for each of the formulas and compared with the actual refractive outcome to give the prediction error. Subgroup analysis based on the steepest corneal power measured by biometry (stage 1: ≤48 diopters [D], stage 2: >48 D and ≤53 D, and stage 3: >53 D) was performed.
Main outcome measure: Prediction error.
Results: On the basis of the mean absolute prediction error (MAE), the formulas were ranked as follows: Kane keratoconus formula (0.81 D), SRK/T (1.00 D), Barrett Universal 2 (1.03 D), unmodified Kane (1.05 D), Holladay 1 (1.18 D), unmodified Holladay 2 (1.19 D), Haigis (1.22 D), Hoffer Q (1.30 D), and Holladay 2 with keratoconus adjustment (1.32 D). The Kane keratoconus formula had a statistically significant lower MAE compared with all formulas (P < 0.01). In stage 3 keratoconus, all nonmodified formulas had a hyperopic mean prediction error ranging from 1.72 to 3.02 D.
Conclusions: The Kane keratoconus formula was the most accurate formula in this series. The SRK/T was the most accurate of the traditional IOL formulas. All normal IOL formulas resulted in hyperopic refractive outcomes that worsened as the corneal power increased. Suggestions for target refractive aims in each stage of keratoconus are given.
MY COMMENTS:
The arguments that I gave on my website:
https://sites.google.com/view/prof-barrett3
apply equally to this article.
I need not go over them again, only to say, that I still maintain that the only, true Keratoconus formula is my Keratoconus formula.
This is rapidly turning into a David vs Goliath struggle.
GENERAL DISCUSSION:
At the moment, we have three, competing groups claiming to have possession of the only, true Keratoconus formula.
We have the Kendrick M. Wang group led by,of course, Kendrick M. Wang and consisting of Kendrick M. Wang, Albert S. Jun, John G. Ladas, Aazim Siddique, Fasika A. Woreta and Divya Srikumaran.
Then, we have the Jack X Kane group led by, of course Jack X Kane and consisting of Jack X Kane, Ben Connell, Harry Yip, James Charles McAlister, Peter Beckingsale, Grant R. Snibson and Elsie Chan.
Then, of course we have me, the Eye Enigma.
Let us first consider the Kendrick M. Wang group.
As you will recall, this group studied the efficacy of the following formulas in the treatment of keratoconus patients requiring cataract surgery:
Hoffer Q, SRK/T, Holladay I, Holladay II, Haigis and Barrett Universal ll formula.
It turned out that the Barrett Universal ll formula was the most accurate for mild to moderate keratoconus and hence the Barrett Universal ll formula was declared to be the winner of that contest.
Next, let us consider the Jack X Kane group.
As you will recall, this group studied the efficacy of the following formulas in the treatment of keratoconus patients requiring cataract surgery :
Kane keratoconus formula, SRK/T, Barrett Universal ll formula, unmodified Kane, Holladay I, unmodified Holladay 2, Haigis, Hoffer Q, and Holladay 2 with keratoconus adjustment.
It turned out that the Kane keratoconus formula was the most accurate formula in that series and hence the Kane keratoconus formula was declared to be the winner of that contest.
Next, the following questions will have to asked:
Will the Kendrick M. Wang group continue to test all of their formulas or only continue testing the Barrett Universal ll formula?
Will the Jack X Kane group continue testing all of their formulas, or only continue testing the Kane keratoconus formula?
Logic would dictate that the Kendrick M. Wang group should discard all of the other formulas and just concentrate on the Barrett Universal ll formula and that the Jack X Kane group should discard all of their other formulas and just concentrate on the Kane keratoconus formula.
This would leave the Barrett Universal ll formula as the sole winner on one side and the Kane keratoconus formula as the sole winner on the other side.
However, the Jack X Kane group has already found in their study that the Kane keratoconus formula was superior to the Barrett Universal ll formula. So then, shouldn't the Kendrick M. Wang group do the honourable thing and drop out of the race altogether , thus leaving the Eye Enigma and Jack X Kane as the only, two remaining contenders for the title of the only, true Keratoconus formula?
The Barrett Universal ll formula was never designed to be used as a keratoconus formula. Its only purpose was to be used as a general purpose formula for normal eyes and it has now been superseded by the Kane formula.
Not only that, we now have newer formulas such as the Kane keratoconus formula, which are designed specifically for keratoconic eyes.
The Barrett Universal ll formula cannot possibly be the only, true Keratoconus formula.
My Keratoconus formula is the only, true Keratoconus formula.
https://sites.google.com/view/haigis
https://sites.google.com/view/kane3
https://sites.google.com/view/prof-barrett3
Written by:
The Eye Enigma
3 March 2021