Abstract
Purpose: :
Long-term effects of pars plana vitrectomy (PPV) like the incidence of open-angle glaucoma and indocyanine green (ICG) toxicity are poorly established. The PROVE Study is an ongoing prospective, controlled clinical trial designed to assess changes in structure and function of the macula and optic nerve following PPV. Interim 3-month data is presented here.
Methods: :
Subjects undergoing unilateral non-emergent PPV are eligible for inclusion. Subjects with glaucoma, visual field defects, prior PPV, or advanced sight-threatening conditions affecting either eye are excluded. Enrollment objective is 40 subjects. Both the eye undergoing PPV (study eye) and the fellow eye (control) are analyzed pre-operatively (baseline), 3-months post-operatively and then yearly for 5 years. Study visits consist of complete examination by a retina and glaucoma specialist, intraocular pressure (IOP) measurements pachymetry, gonioscopy, Humphrey visual field (HVF) testing, fundus photography with autofluorescence, and optic nerve and macula optical coherence tomography (OCT) testing. Primary outcomes for this sub-analysis are changes in IOP, HVF, cup-disc ratio, peripapillary retinal nerve fiber layer (RNFL), and macular central subfield thickness (CST).
Results: :
Ten subjects have completed 3-month follow-up. Surgical indications included 4 eyes with macular hole (MH), 4 epiretinal membranes (ERM) and 2 vitreous opacities (VO). Baseline mean IOP (mmHg) was 18 ± 3 (standard deviation) and 18 ± 2.6 for study and fellow eyes, respectively and 16 ± 3 and 17 ± 2 at 3-months, respectively. Only one patient developed HVF changes concerning for glaucoma. No progression of cupping was observed in this cohort at 3 months. Baseline mean RNFL thickness (µm) was 95 ± 9 and 92 ± 4 for study and fellow eyes, respectively and 87 ± 13 and 93 ± 5 at 3-months, respectively. In 4 eyes with MH that underwent ICG staining with internal limiting membrane (ILM) removal, mean RNFL thickness was 15 µm less compared with fellow eyes (temporal RNFL quadrant 22 µm thinner, P=0.19). Mean baseline CST (µm) of 4 subjects with ERM was 395 and 255 for study and fellow eyes respectively. While mean CST in study eyes decreased 75 µm 3 months after PPV, it remained 70 µm thicker compared with fellow eyes (250 µm, P=0.15).
Conclusions: :
In this ongoing prospective study, interim analysis suggests no significant change in IOP, HVF, cup-disc ratio, peripapillary retinal nerve fiber layer (RNFL), and macular central subfield thickness (CST).
Clinical Trial: :
http://www.clinicaltrials.gov NCT01162356
Keywords: vitreoretinal surgery • intraocular pressure • clinical (human) or epidemiologic studies: outcomes/complications