ESCRS - PP13.07 - Accuracy Of Barrett And Kane Formulae In Keratoconus Patients

Accuracy Of Barrett And Kane Formulae In Keratoconus Patients

Published 2022 - 40th Congress of the ESCRS

Reference: PP13.07 | Type: ESCRS 2022 - Posters | DOI: 10.82333/7eex-dv49

Authors: Vaishal Kenia* 1 , Raj Kenia 1 , Sneha Maru 1 , Laxmi Mudaliya 1 , Onkar Pirdankar 1

1KENIA EYE HOSPITAL,MUMBAI,India

Purpose

To compare accuracy of Barrett and Kane formulae in keratoconus patients

Setting

Private Eye Hospital, India

Methods

A retrospective study where keratoconus subjects diagnosed with Grade 1 central keratoconus (K<48.00D), age ranged between 45-75 years were enrolled. Subjects with any systemic illness, previous corneal surgery, intraoperative complications were excluded. Post operative 1 month refraction was noted. IOL power calculations were done using Barrett (Barrett  Univarsal 2 (Bar U2), Barrett  total K (BarTK), Barrett True K (Bar TRK), measured Barrett True K (Mea Bar TRK) and Kane KC formulae. Median Absolute error (MedAE) was calculated as median of absolute difference between post operative and target refraction spherical equivalent. Also percentage of eyes with absolute error spherical equivalent within 0.5D, >0.51 D were noted. 

Results

23 eyes with mean±SD age 62.21±7.0 years were included. All the Barrett variants resulted in similar refractive outcomes. Median Absolute error with Bar 2, BarTK, Pred Bar TRK, Mea Bar TRK and Kane was 0.33, 0.22, 0.19, 0.26 and 0.24D respectively.  82.60% and 17.40% eyes had spherical equivalent within 0.50D and >0.51D respectively using Kane formula. With all four variant of Barrett, 78.26% and 21.74% eyes had spherical equivalent within 0.50D and >0.51D respectively.

Conclusions

In keratoconus eyes, specialised formulae like Barrett total K, Barrett true K, Barrett true K measured and Kane KC performed better.