ABSTRACT
BACKGROUND: Amblyopia is a relatively common condition in which visual acuity through an eye is subnormal despite no overt pathology. Pattern visual evoked potential (PVEP) can detect any defect from optic nerve to occipital cortex and pattern electroretinogram (PERG) can detect retinal defects specially the ganglion layers. This study was performed to evaluate the cortical and retinal activity in strabismic and anisometropic amblyopia. METHODS: PVEP and PERG were recorded simultaneously in 40 amblyopes (20 strabismics and 20 anisometropics) and 20 normal control subjects. Normal subjects were age and sex matched with patients. RESULTS: The P(100) latency in PVEP was increased in both groups of patients but the P(100) amplitude was reduced only in anisometropic group. In PERG, the amplitude of P(50) was reduced in all patients with no significant change in latency. CONCLUSION: Beside reduced PVEP responses in strabismic and anisometropic amblyopia, the activity of retina reduced too. It is likely that retinal impulses can affect the development of visual system.
ABSTRACT
Contrast sensitivity is proposed as a potential screening tool for the early detection of diabetic retinopathy. A cross-sectional study was performed in a tertiary referral university eye centre. A total of 80 diabetes patients were recruited and tests were performed on 154 eyes. Contrast sensitivity was checked using Cambridge low-contrast grating. Abnormal contrast sensitivity was observed in 27.1% of eyes with diabetic retinopathy, compared with 9.0% in unaffected eyes, a statistically significant difference. Cambridge low-contrast grating is a potential screening tool for early detection of diabetic retinopathy by non-ophthalmologists.
Subject(s)
Contrast Sensitivity , Diabetic Retinopathy/diagnosis , Vision Screening/methods , Aged , Analysis of Variance , Case-Control Studies , Chi-Square Distribution , Cross-Sectional Studies , Diabetes Mellitus, Type 1/complications , Diabetes Mellitus, Type 1/metabolism , Diabetes Mellitus, Type 1/therapy , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/metabolism , Diabetes Mellitus, Type 2/therapy , Diabetic Retinopathy/epidemiology , Diabetic Retinopathy/etiology , Disease Progression , Early Diagnosis , Female , Humans , Iran/epidemiology , Male , Ophthalmoscopy , Sensitivity and Specificity , Severity of Illness Index , Single-Blind Method , Surveys and Questionnaires , Time Factors , Vision Screening/standards , Visual AcuityABSTRACT
Contrast sensitivity is proposed as a potential screening tool for the early detection of diabetic retinopathy. A cross-sectional study was performed in a tertiary referral university eye centre. A total of 80 diabetes patients were recruited and tests were performed on 154 eyes. Contrast sensitivity was checked using Cambridge low-contrast grating. Abnormal contrast sensitivity was observed in 27.1% of eyes with diabetic retinopathy, compared with 9.0% in unaffected eyes, a statistically significant difference. Cambridge low-contrast grating is a potential screening tool for early detection of diabetic retinopathy by non-ophthalmologistsp
Subject(s)
Cross-Sectional Studies , Sensitivity and Specificity , Diabetic Retinopathy , Contrast Sensitivity , Diabetes ComplicationsABSTRACT
Monocular and binocular transient visually evoked responses (VER) were recorded on 50 adult subjects using a pattern reversal stimulus (check size 5.5 min arc). The peak-to-trough amplitude of the VER wave was measured and compared with the subjective visual acuity (Landolt C). The binocular amplitude enhancement over the monocular amplitude was around 26% across the acuity range studied, whereas the mean binocular subjective visual acuity improvement was around 11.3%, but this varied from 1% at the high acuity end to 17% at the low acuity end of the range.
