Accuracy of new postoperative ACD prediction formula using anterior segment OCT

Abstract

Purpose : To examine the accuracy of a new prediction formula for postoperative anterior chamber depth (ACD), which we devised from measured values by anterior segment optical coherence tomography (OCT).

Methods : The new prediction formula for postoperative ACD was devised from measurements in 65 eyes of 47 patients (74.5±6.9 years; Group A) implanted with AcrySof® (Alcon) intraocular lens (IOL) at Kanazawa Medical University Hospital from June 2016 through April 2017, and tested in 32 eyes (72.3±7.4 years; Group B) likewise implanted. The preoperative angle-to-angle depth (ATAD) from the corneal posterior zenith (CPZ) to the angle-to-angle width, the central clear zone depth (CCZD) from CPZ to the central clear zone, and lens equator depth (LED) from CPZ to the lens equatorial width, and the postoperative ACD from CPZ to the IOL anterior zenith at 1-month after cataract surgery, were measured using anterior segment OCT (CASIA2/TOMEY in Biometry-mode).

Results : As the correlation with postoperative ACD in Group A was higher in CCZD (R²=0.643), LED (R²=0.619), and ATAD (R²=0.485) in order, the prediction formula [postoperative ACD = CCZD×0.43+LED×0.295+ATAD×0.284 – 0.172 (R²=0.84, p<0.001)] was devised using multiple linear regression analysis. In Group B, there was a strong correlation between the prediction formula and actual measured values [y = 1.054x – 0.322 (R²=0.86, p<0.001)]. The average error between the measured and predicted values of the postoperative ACD was 0.09±0.12 mm, and its corresponding refraction error was 0.12±0.146D. The rates of prediction of ACD within±0.25D, ±0.50D, and ±0.75D were 78.1%, 93.8%, and 100%, respectively.

Conclusions : The prediction formula for postoperative ACD, calculated with ATAD, CCZD, and LED, showed high accuracy, and may be useful for preoperative estimation.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.