Measurement of Changes in Angle Configuration Following Phacoemulsification Using the Anterior Segment OCT

Abstract

Purpose: : To measure changes in angle configuration following phacoemulsification using anterior segment OCT.

Methods: : Patients undergoing phacoemulsification at the National University Hospital, Singapore, were included in the study. Imaging of the eye scheduled for surgery was done using AS–OCT prior to cataract surgery and repeated at least one month following surgery. We specially sought to include subjects with suspected narrow angles. Images were obtained of the nasal, temporal and inferior angle quadrants in dark conditions. Images were analysed by a masked observer using custom software (Mathworks Inc., Natick, MA). Differences between pre and post–phaco measurements of angle opening distance at 500µm (AOD₅₀₀), angle recess area (ARA₅₀₀), and trabecular–iris space area (TISA₅₀₀) were calculated for each angle quadrant and were subject to statistical analysis using the paired samples test.

Results: : Twenty–one eyes of 21 subjects were included in the study. The mean age was 70.5 years +/– 7.6 and 11 of the subjects were men. Following phacoemulsification there was a significant increase in AOD₅₀₀, ARA₅₀₀, and TISA₅₀₀ in the nasal, temporal and inferior angle quadrants relative to pre–operative measurements. (see table)

Conclusions: : Quantitative analysis of changes in angle configuration following cataract extraction reveals a significant increase in all measured parameters. Using AS–OCT imaging the angle opening distance (AOD₅₀₀), angle recess area (ARA₅₀₀) and trabecular–iris space area (TISA₅₀₀) are shown to increase in the nasal, temporal and inferior angle quadrants.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • cataract • anterior segment