Evaluation of choroidal thickness with EDI-OCT in primary open-angle glaucoma cases

OBJECTİVE: Examining the change of choroidal thickness and the effect of anti-glaucomatous treatment to choroidal thickness in primary open angle glaucoma (POAG) by using EDI-OCT. MATERİAL AND METHODS: Prospective and non-interventional study was planned that included 50 patients had not received treatment of glaucoma, diagnosed with POAG and 50 healty volunteers, admitted to clinic without any ocular pathology. Antiglaucomatous monotheraphy was started for glaucoma patients and cases who met the inclusion criteria were followed up for 6 months. At baseline all samples underwent best-corrected visual acuity (BCVA), intraocular pressure (IOP), central corneal thickness (CCT) and optical coherence tomography (OCT) assessments, visual field (VF) tests and mfERG. In all visits, BCVA, IOP assessments, OCT scans and VF tests were performed. In addition mfERG recordings were obtained at month 1,3 and 6. Results were compared statistically. RESULTS: 96 patients completed the study. There were significant differences between the mean values of choroidal thicknesses of glaucoma and control groups in all visits. Mean value of choroidal thickness decreased from 254.91 μm to 237.55 μm at month 6 in glaucoma group. Initial mean value of choroidal thickness was 287.42 μm and the mean value was 285.02 μm at month 6 in control group, there was no significant decrease for control group.Reduction of the mean choroidal thickness was not observed in glaucoma patients using Brinzolamid+Timolol, Dorzolamid+Timolol ve Bimatoprost+Timolol (p>0.05) in the progression analysis.It was observed that as OCT parameters, mean values retinal nerve fiber layer thickness (RNFL), inferior quadrant of optical disk RNFL thickness and neuroretinal rim area of glaucoma group were significantly lower than control group in all controls. In addition, the mean values of cup volume (CV), average cup-disc rate (ACDR) and vertical cup-disc rate (VCDR) were significantly higher in control group compared to control group. As multifocal electroretinography recording, only the mean amplitude value of 1.ring N1 wave and 2.ring P1 wave were lower in glaucoma group compared to the control group. There were significant correlations between the mean value of RNFL, the mean deviation (MD) and pattern standart deviation (PSD) and the mean BCVA value for both groups.While there was a significant correlation between BCVA and RNFL for glaucoma group, and significant correlations were found between the mean value of ACDR, VCDR, N1- P2 wave amplitudes and choroidal thickness for the control group. CONCLUSION: Decline of choroidal thickness may be seen in POAG. In addition, although controlling IOP, choroidal thickness reduction may continue in POAG. However, as a anti-glocomatous treatment, using brinzolamide + timolol, dorzolamide+ timolol or bimatoprost +timolol may prevent choroidal thickness decrease in POAG.When we look at these results, larger prospective studies in the future will hold more open and detailed light on this issue. There is no enough diagnostic value of mfERG in the early stage of glaucoma.