ESCRS - POCAT597 - Refractive Prediction Accuracy Of Barrett True-K Versus Intraoperative Aberrometry (Ora) In Post-Radial Keratotomy (Rk) Cataract Surgery.

Refractive Prediction Accuracy Of Barrett True-K Versus Intraoperative Aberrometry (Ora) In Post-Radial Keratotomy (Rk) Cataract Surgery.

Published 2026 - 44th Congress of the ESCRS

Reference: POCAT597 | Type: Free paper | DOI: 10.82333/dmtp-sp40

Authors: Prof. Dr Amit Gupta* 1 , Dr VIPASHA SHARMA 2 , LEKHA CHANDEL 2 , Dr DEEKSHA SHARMA 2 , Sonam Yangzes 2 , CHINTAN MALHOTRA 2

1AEC,PGIMER,CHANDIGARH,India;AEC,PGIMER,CHANDIGARH,India, 2AEC,PGIMER,CHANDIGARH,India

Purpose

To compare the refractive prediction accuracy of the Barrett True K formula and intraoperative wavefront aberrometry (ORA) in post RK cataract surgery by assessing mean absolute error (MAE), arithmetic mean error (AME), and the proportion of eyes within ±0.50 D, ±1.00 D, and ±2.00 D of predicted postoperative refraction.

Setting

Advanced Eye Centre, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India. Retrospective comparative study.

Methods

Thirty-six post-RK eyes of 27 patients (9 bilateral) undergoing cataract surgery were retrospectively analysed. Preoperative biometry using the IOLMaster version 700 (Carl Zeiss Meditec AG) was performed, and IOL power was calculated with the Barrett True-K formula for post-RK eyes. Intraoperative aphakic measurements were obtained using the Optiwave Refractive Analysis (ORA) system (Alcon). Postoperative spherical equivalent was recorded, and prediction error (actual minus predicted refraction) was calculated. Mean Arithmetic Error (MAE), AME, and percentages within ±0.50 D, ±1.00 D, and ±2.00 D were analyzed using paired statistical testing.

Results

Mean age was 51.09 ± 6.71 years and mean axial length was 27.97 ± 2.54 mm (range 24-32.74 mm). Ten eyes had 8 or less incisions, 12 eyes had 12 or less incisions, 6 eyes had combine RK with Ak incisions and 8 eyes had more than 16 RK incisions. Both methods demonstrated good refractive accuracy. ORA showed a numerically lower MAE compared with Barrett (0.98 D vs 1.27 D; p = 0.197). The proportion of eyes within ±0.50 D was 41.7% (ORA) versus 38.9% (Barrett); within ±1.00 D, 66.7% versus 63.9%; and within ±2.00 D, 94.4% versus 77.8% respectively. Both methods exhibited mild myopic bias (AME −0.39 D vs −0.43 D; p = 0.878).

Conclusions

Both the Barrett formula and intraoperative aberrometry demonstrated satisfactory refractive prediction accuracy in this cohort. ORA showed a trend toward slightly improved precision and a higher proportion of eyes within broader refractive thresholds, although differences were not statistically significant. While no tool is perfect, intraoperative aberrometry brings us closer to customised real time precision for each patient.