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

Abstract

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. Retrospective, comparative case series. 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. 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 ± 2.0mm Hg in STE and 10.8 ± 0.8mm 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). The structure of the mGCIPL was better preserved in STE than in MTE, even when the IOPs during follow-up were similar.