Comparison of Changes in Macular Ganglion Cell-Inner Plexiform Layer Thickness Between Medically and Surgically Treated Eyes With Advanced Glaucoma

Abstract

Purpose: To compare changes in the macular ganglion cell layer and inner plexiform layer (mGCIPL) thickness over 5 years between surgically treated eyes (STE) and medically treated eyes (MTE) with advanced glaucoma.

Design: Retrospective, comparative case series.

Methods: Eighty-six patients comprising 43 with open-angle glaucoma (OAG) with trabeculectomy and 43 with medically treated OAG. The mGCIPL thickness was measured more than 5 times during follow-up by optical coherence tomography. Main outcome measure was differences in mGCIPL thickness thinning rate between the groups.

Results: The mean age at study initiation was 62.5 ± 9.2 years in STE and 62.7 ± 9.5 years in MTE. The mean deviations (MD), according to the Humphrey Field Analyzer central program 30-2, and the mGCIPL thickness in each sector showed no significant differences at initial measurement. The averaged intraocular pressure (IOP) throughout follow-up was 10.5 ± 2.0 mm Hg in STE and 10.8 ± 0.8 mm Hg in MTE (P = .429; Mann-Whitney U test). There was no significant difference in the MD changes over 5 years between the 2 groups (P = .405; Mann-Whitney U test). Changes in the mGCIPL thickness over 5 years in MTE were significantly greater than that in STE in all sectors (all 6 sectors P < .0001, Mann-Whitney U test). The IOP fluctuation over 5 years in STE was significantly less than that in MTE (P < .0001, Mann-Whitney U test).

Conclusions: The structure of the mGCIPL was better preserved in STE than in MTE, even when the IOPs during follow-up were similar.