الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The aim of this study is to investigate the structure- function relationships in glaucoma suspect & early open angle glaucoma patients by using three different imaging techniques. The structural changes are recorded using SD-OCT while functional changes evaluation by using two tests; standard automated perimetry (subjective method) which is considered the gold standard test for glaucomatous changes and multifocal electroretinogram( mfERG ) which is objective method used for visual function evaluation.
Forty eyes of 21 patients and twenty eyes of 10 normal individuals as a control group were enrolled in this prospective comparative non-randomized study. They were recruited from the outpatient clinic of Ophthalmology department, Minia University Hospital.The patents were divided into three groups 1- group 1: included 20 eyes of 10 patients suspected to have POAG glaucoma.
2- group 2: included 20 eyes of 11 patients with early POAG
3-group 3: included 20 eyes of 10 healthy individuals.
Patients with history of ocular or systemic diseases, causes of secondary glaucoma, non- glaucomatous optic neuropathy, any retinal or macular dystrophy and history of ocular surgery were excluded from the study. As well as, patients with BCVA < 6/60, refractive error > ±5 diopter, involuntary ocular movement (nystagmus) .
All patients underwent comprehensive ophthalmological evaluation. Standard automated perimetry was recorded using the Humphrey Field Analyzer II.The strategy used was 24-2 Swedish interactive thresholding algorithm (SITA) full-threshold for 54 retinal locations and Background illumination was 31.5 abs, stimulus size III and white colour on white background. Tests with more than 20% fixation lose and more than 20% false positive or false negative were excluded.
The optical coherence tomography was performed with the SD-OCT (RTVue XR 100 Avanti). The RNFL thickness was obtained from the ONH scan, the parameters are derived from a 3.45 mm circle centered on the optic disc. The GCC scan was done by scanning 6 mm circle centered 1mm temporal to the fovea in order to emphasize the temporal region, which corresponds to the nasal visual field (area most susceptible to early glaucomatous damage).
The multifocal electroretinogram was recorded on the RETI-port/scan2/ mfERG version 19-99_D4_7_14E (Roland Consult, Wiesbaden, Germany), according to the standard ISCEV guidelines of mfERG recording.
The data used in analysis were both global and hemispheric (superior and inferior hemispheres) to facilitate the analysis and make it more reliable as the correlation was done between the corresponding areas of the retina which assessed in OCT, mfERG and HFA.
In the present study we found that, in early stages of POAG, mfERG has a significant correlation with OCT parameters, while the correlation between HFA and OCT was poor. This finding can be explained based on theories of pathophysiology of POAG. If the pathology is mainly on the optic disc and its vasculature, it will affect the structure of RNFL thickness by OCT but will not affect mfERG or VF at early stages. If the pathology is mainly in the ganglion cell layer, so it will affect its thickness on macular OCT and on mfERG but not on VF.