Sequential morphological and functional features of retinal damage in mice exposed to different doses (40 vs. 20 mg/kg) of sodium iodate (NaIO3) were analyzed. Retinal morphology, apoptosis (TUNEL assay), and function (electroretinography; ERG) were examined at several time points after NaIO3 administration. The higher dose of NaIO3 caused progressive degeneration of the whole retinal area and total suppression of scotopic and photopic ERG. In contrast, the lower dose induced much less severe degeneration in peripheral part of retina along with a moderate decline of b- and a-wave amplitudes in ERG, corroborating the presence of regions within retina that retain their function. The peak of photoreceptor apoptosis was found on the 3rd day, but the lower dose induced more intense reaction within the central retina than in its peripheral region. In conclusion, these results indicate that peripheral area of the retina reveals better resistance to NaIO3 injury than its central part.
PurposeTo evaluate photopic negative response (PhNR) discrimination ability between healthy and glaucomatous patients.
MethodsNinety eyes of 50 patients with primary open angle glaucoma (POAG) and 45 eyes of 23 healthy age- and sex-matched controls were investigated. Based on European Glaucoma Society criteria, POAG patients were divided into three groups: early, moderate and advanced glaucoma. Following measurements were analysed: mean defect (MD) from Humphrey Visual Field Analyzer, SITA standard 24-2 white on white perimetry; nerve fibre index (NFI) obtained from scanning laser polarimetry; and GDx and PhNR amplitude and PhNR/b-wave ratio. PhNR was elicited by red stimuli with flash strength of 1.6 cd s/m2 on blue background of 25 cd/m2. Correlations between retinal ganglion cells function (PhNR), retinal sensitivity (MD) and structure (NFI) were calculated. Sensitivity and specificity of PhNR parameters were calculated with standard formulas. Receiver operating characteristic (ROC) curves were used to determine optimal cut-off values. The area under the curve (AUC) was used to compare the ROC curves results between PhNR amplitude and ratio.ResultsPhNR amplitude and ratio were significantly reduced in early, moderate and advanced glaucoma groups compared to controls. The sensitivity and specificity to detect glaucoma in early POAG were equal to 53.3 and 90.0 % for PhNR amplitude and 60.0 and 70.0 % for PhNR ratio; in moderate POAG 63.3 and 80.0 % for PhNR amplitude and 60.0 and 86.7 % for PhNR ratio; and in advanced POAG 76.6 and 80.0 % for PhNR amplitude, 90.0 and 73.3 % for PhNR ratio. There were no significant differences between AUC for PhNR amplitude (0.76–0.86) and PhNR ratio (0.78–0.86), p > 0.05. PhNR amplitudes and ratios correlated significantly with MD measured by SAP and NFI obtained from GDx (p < 0.05). PhNR amplitude significantly decreases with advancement of visual field defects in glaucoma patients.ConclusionsPhNR reveals dysfunction of RGCs in early, moderate and advanced stage of POAG. PhNR has good discrimination ability in detecting glaucomatous patients. PhNR might be a useful test in glaucoma diagnosis.
Background To evaluate retinal ganglion cell (RGC) function after intraocular pressure (IOP) reduction measured by pattern electroretinogram (PERG) in patients with newly diagnosed, non-treated preperimetric and early stages of primary open-angle glaucoma (POAG).MethodsTwenty-four eyes from 24 patients with POAG: 11 eyes with preperimetric glaucoma and 13 eyes with early glaucoma received Ganfort
® (bimatoprost + timolol) once a day for a period of 1 month. Before and after the treatment, following measurements were analyzed: IOP, mean ocular perfusion pressure (MOPP), peak time of P50 and amplitude of P50 and N95 waves in PERG (ISCEV standard 2012). Correlations between PERG P50 and N95 waves, IOP and MOPP were calculated.ResultsAfter therapy, IOP significantly decreased in all eyes, on average 31%. Significant increase in MOPP in all eyes on average 14% was detected. PERG amplitude of P50 and N95 waves increased in 75 and 79% eyes, respectively, on average P50 by 28% and N95 by 38%. There were no significant interactions between the change of PERG parameters in time and stage of glaucoma.ConclusionsSignificant IOP-lowering therapy can improve RGC function measured by PERG, in patients with preperimetric and early stages of POAG.
A new case with OMD is added to preceding reports. The mfERG and OCT tests are important in detection of OMD patients. It can help in differential diagnosis of amblyopia, optic nerve diseases and non-organic visual disorders.
PurposeTo asses the retinal pigment epithelium (RPE) function measured by EOG testing in patients with neurofibromatosis type 1 (NF-1). Our preliminary EOG results suggested dysfunction of the RPE in individuals with NF-1. In order to confirm our initial results we performed EOG examination on a larger group of NF-1 patients.PatientsStudies were performed on 36 patients with clinically diagnosed NF-1 and compared to normal healthy controls.MethodsStandard EOG recordings were performed in accordance with the International Society for Clinical Electrophysiology of Vision (ISCEV) standards.ResultsIn NF-1 patients the Arden indexes of the EOG test were significantly higher primarily due to the lower values of dark troughs. Supernormal EOGs (exceeding the value of the mean + 2 SD from the control group) were present in 58% of NF-1 patients.ConclusionsDysfunction of the RPE is a characteristic feature of individuals with NF-1.
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