Comparing the Effect of Laser Peripheral Iridotomy to Lens Extraction on Anterior Segment Morphology in Narrow Angle Eyes using Anterior Segment Optical Coherence Tomography (ASOCT)

Abstract

 

Purpose

 

To measure changes in the trabecular-iris space area (TISA) and trabecular-iris circumference volume (TICV) in eyes with narrow angles from laser peripheral iridotomy (LPI) or lens extraction (LE) using ASOCT

 

Methods

 

Eyes with narrow angles scheduled for LE or LPI were recruited from the Robert Cizik Eye Clinic/UTHealth and enrolled in a prospective observational study. Each patient underwent an ocular examination including slit lamp, intraocular pressure (IOP) and gonioscopy followed by ASOCT imaging preoperatively and postoperatively. Images were then read by an experienced reader, and TISA500 and TICV500 were used to assess the change in the angle pre- and post-LE and LPI. A mixed effect model was used.

 

Results

 

Patients with narrow angles who underwent LE (29 eyes from 21 patients) and LPI (40 eyes from 25 patients) were enrolled. Demographics and results are in tables 1 and 2.

 

Conclusions

 

LE and LPI both produce deepening in the anterior chamber angle, which can be measured using ASOCT. While both treatments are effective in deepening the angle, LE showed a proportionately greater postoperative change in both TISA500 and TICV500 measurements. Both LPI and LE are effective for deepening the angle, but LE deepens the angle two times as great. This suggests that both may potentially be effective treatments in disease states where deepening of the angle is required. The relationship between the amount of angle deepening and efficacy of treatment of angle closure remains undefined.

 

 

Table 1. Summary Statistics for Demographics (LE = Lens Extraction; LPI = Laser Peripheral Iridotomy)

 

 

Table 2. Angle Measurements Before and After Procedure (LE = Lens Extraction; LPI = Laser Peripheral Iridotomy; TISA = Trabecular-Iris Space Area; TICV = Trabecular-Iris Circumference Volume)

 

Keywords: 421 anterior segment • 550 imaging/image analysis: clinical • 445 cataract