Quantitative topographic irregularity a a predictor of pectacle-corrected viual acuity after refractive urgery

PURPOE: To evaluate a new topographic index called topographic irregularity a a quantitative predictor of corrected viion after refractive urgery. METHOD: We defined topographic irregularity a the ummed difference at all point between a topographic refractive corneal power map and it bet-fit pherocylinder. We propectively tudied 107 eye of 107 patient 3 month after a variety of refractive procedure. Topographic irregularity wa calculated from topographic map, and the correlation between topographic irregularity and pectacle-corrected viual acuity wa determined uing both high-contrat and low-contrat acuity chart. Thi correlation wa compared with correlation for the urface regularity index and the urface aymmetry index. Next, we analyzed 54 of thee topographic map to create a regreion cale relating urface regularity index, urface aymmetry index, and topographic irregularity to predict pectacle-corrected viual acuity. Thi cale wa then ued to predict pectacle-corrected viual acuity on the remaining 53 potoperative patient. REULT: The correlation of topographic irregularity with pectacle-corrected viual acuity (R2 = .36) wa comparable to the correlation for the urface regularity index (R2 = .36) and tronger than for the urface aymmetry index (R2 = .11) when pectacle-corrected viual acuity wa meaured with high-contrat eye chart. Topographic irregularity correlated more trongly with pectacle-corrected viual acuity (R2 = .42) than either the urface regularity index (R2 = .28) or the urface aymmetry index (R2 = .14) when pectacle-corrected viual acuity wa meaured with low-contrat eye chart. Uing the regreion cale, prediction of high-contrat and low-contrat pectacle-corrected viual acuity from topographic irregularity wa uperior to or comparable to prediction uing the urface regularity index and the urface aymmetry index. CONCLUION: Topographic irregularity ha a cloer correlation with pectacle-corrected viual acuity than exiting topographic indexe. Topographic irregularity i alo an accurate predictor of pectacle-corrected viual acuity and may be a more enitive tool for evaluating potoperative viual performance than current topographic meaure.