In Vivo Imaging of the Schlemm's Canal and the Response to Selective Laser Trabeculoplasty.

OBJECTIVE

To evaluate the presence of angle dysgenesis on ASOCT (anterior segment optical coherence tomography) (ADoA) as a predictive factor in determining outcomes of selective laser trabeculoplasty (SLT).

DESIGN

A prospective clinical cohort study.

SUBJECTS

Patients with juvenile-onset open-angle glaucoma (JOAG) without angle dysgenesis on gonioscopy.

METHOD

JOAG patients with uncontrolled intraocular pressure (IOP), who were to undergo SLT, were evaluated for the presence or absence of ADoA, which was defined as the absence of Schlemm's canal (SC) and/or presence of a hyperreflective membrane (HM) over the trabecular meshwork, as identified on ASOCT before the SLT procedure. Furthermore, the number of ASOCT B-scans in which SC was identified as present, were then quantified. Success of SLT was defined as a reduction of IOP by 20% or more from pre-laser value at 6-month follow-up without any further IOP-lowering medication or surgery. Only 1 repeat SLT was admissible for defining SLT success over the 6-month period. A successful reduction in IOP at 6-month follow-up was correlated with the extent of ADoA.

RESULTS

In comparison to pre-SLT IOP, 57.1% eyes (20/35) showed more than 20% reduction in IOP at 6 months with a mean reduction of 7.6 ± 1.8 mm Hg (29.6%). When all 3 observers agreed, SC was identified in 90% eyes (18/20) with success vs 26.6% eyes (4/15) with failure (P 50% ASOCT B scans (>25/50 scans/eye) showed success (P 50% of ASOCT scans was associated with a 21.4 times greater chance of success.

CONCLUSIONS

The presence of SC on ASOCT is a strong predictor for successful IOP reduction after SLT in JOAG eyes.