Clinical Analysis of Electroretinogram in Hypertensive Retinopathy

PURPOSE: Among electroretinogram variables, changes in OPs have frequently been reported as an early index of microcirculatory changes in diabetes mellitus patients without clinical signs of diabetic retinopathy. But studies on the relationship of hypertensive retinopathy and ERG have rarely been reported. This study was performed to investigate the relationship between retinal functional damage of hypertension and related changes in ERG. METHODS: Sixty-six essential hypertensive patients who visited our health screening center from January to July in 2001 were incruited as subjects. Among 122 eyes of 61 patients, 56 eyes with normal appearing retina were classified as group A while another 66 eyes with evidence of hypertensive retinopathy were as group B and 30 eyes of 15 persons of similar ages with normal blood pressure were normal control group as group C. Amplitude and implicit time were measured according to the standard electroretinogram procedure recommended by the ISCEV. RESULTS: In rod response, the amplitude of b wave of group A and B were smaller than that of group C(p<0.01), and the SOP of group A and B were also smaller than that of group C(p<0.01). The SOP of group B was smaller than that of group A(P<0.01). Regardless of degree of hypertension, the SOP value of group B was smaller than that of group A(P<0.01). Among patients with less than 5 years of duration, the SOP value of group B was smaller than that of group A(P<0.01). Among Group A with more than 5 years of duration, regardless of hypertensive retinopathy, the SOP was decreased. Among Group B with less than 5 years of duration, the SOP was also decreased regardless of retinopathy. CONCLUSIONS: Regardless of hypertensive retinopahy, scotopic b-amplitude and SOP were reduced in hypertension patients. Those patient with longer duration, decreased SOP was related to microcirculation alteration in hypertension despite normal appearing retina.

The Usefulness of Standard Electroretinogram in Classification of Central Retinal Vein Occlusion

PURPOSE: Central retinal vein occlusion is classified as ischemic and non-ischemic types. Ischemic type has poor visual prognosis because of neovascular complications. Fluorescein angiography shows lower reproducibility and predictability of neovascularization and has complications although it has been the standard method for classification. This study was made to determine the usefulness of the electroretinogram (ERG) in the classification and predictor of neovascularization. METHODS: Forty-two eyes with central retinal vein occlusion were classified as ischemic and non-ischemic groups by means of indirect ophthalmoscope and fluorescein angiography finding. All patients were examined with standard electroretinogram and followed. During the follow-up period, development of neovascularization was evaluated. All parameters of electroretinogram were analyzed. RESULTS: Compared to the control group, a and b wave amplitudes in maximal combined response, b/a ratio, b wave amplitude in cone response, and b wave implicit time in 30Hz flicker response showed statistically significant difference in only ischemic central retinal vein occlusion (P<0.05). Compared to the control group, a and b wave amplitudes in maximal combined response, b/a ratio show statistically significant difference in only central retinal vein occlusion with rubeosis. CONCLUSIONS: Standard electroretinogram is thought to be a useful method for classifying the central retinal vein occlusion and predicting the rubeosis in central retinal vein occlusion.

Us efulness of Standard Electro retinogram in the Early Diagnosis of Diabetic Retinopathy: Analysis using Receiver Operating Characteristic(ROC) Curve

Authors recorded standard electroretinogram in two groups of diabetic patients. Group A, consisted of 60 eyes with no visible diabetic retinopathy and Group B, 30 eyes with mild nonproliferative diabetic retinopathy. The electroretinogram was recorded according to the standard electroretinogram procedure recommanded by the ISCEV. In rod and cone response, the amplitude of b wave were 329.0+/-46.9 microvoltin Group A and 308.8+/-37.8 microvoltin Group B. The implicit time of b wave were 40.5+/-3. 0microvoltin Group A and 45.8+/-5.4microvolti n Group B. The summed amplitude of oscillatory potentials were 125.7+/-38.7microvolt in Group A and 112.0+/-17.7microvoltin Group B. Above results indicate that for the disgnostic criteria for diabetic retinopathy, the amplitude and implict time of b wave, and the summed amplitude of oscillatory potentials in maximal combined response were useful. On receiver operating characteristic(ROC) curves in maximal combined response, cut off value for the amplitude and implicit time of b wave were 315 microvoltand 42ms espectively. Cut off value for the summed amplitude of oscillatory potentia-als was 118 microvolt. In results, on ROC curve, the implicit time of b wave in maximal combined response was most accurate, and the summed amplitude of oscillary potentials was the next, followed by the amplitude of b wave in the maximal combined response.