Evaluation of Ocular Biometry in PACD With Two Swept Source Optical Coherence Tomography Devices

Primary angle-closure disease (PACD) is the leading cause of blindness worldwide. PACD is an anatomic disorder, typically of relatively small eye with shallow anterior chamber depth (ACD), thick lens, shorter axial length (AL), small corneal curvature, and relatively anterior lens position. Pupillary block, plateau iris and phacomorphic mechanisms play major roles in the pathophysiology of the disease, and pupillary block is thought to be the most common causal mechanism.

For decades, phacoemulsification and intraocular lens implantation (PEI) has been proposed for initial management of PACD.4 PEI relieves pupillary block, deepening ACD and widening irido-corneal angle.

Biometry is essential in evaluating ocular dimensions and calculating IOL power in PACD, and ocular biometers have been evolving in recent years. Optical coherence tomography (OCT) includes partial coherence interferometry (PCI), and swept source OCT (SS-OCT) is in general use in clinical practice. The agreement of the calculations of these devices has been studied by many investigators; however, research into their agreement in PACD patients has been sparse so far. A newer SS-OCT, Anterion, is now available and its performance needs to be evaluated.