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Biomedical subjects

G H Bresnick

Publications and source records attributed to G H Bresnick.

At least 37 records · Page 2Linked to original sources
PubMed1987

Temporal aspects of the electroretinogram in diabetic retinopathy.

We measured the temporal aspects of several components of the electroretinogram in 72 patients with diabetes and 29 control subjects. The measurements consisted of the implicit times of the a wave and oscillatory potentials elicited by a bright-flash stimulus and the implicit time of the b wave in response to a 30-Hz flickering light. The a wave and first three oscillatory potential nodes were significantly delayed in the patients with diabetes compared with the controls; among the diabetics, a significant increase in the delay of the second and third nodes occurred as a function of increasing retinopathy severity. Similarly, the 30-Hz flicker implicit times (with and without a background light) were significantly delayed in patients with diabetes, and the magnitude of the delay increased with increasing retinopathy severity. The correlations of 30-Hz flicker implicit times with retinopathy severity were significant for retinopathy level graded in color fundus photographs as well as for retinal capillary nonperfusion and leakage graded in fluorescein angiograms. A comparison of 30-Hz flicker implicit times in 15 patients with one eye treated with panretinal laser photocoagulation and the other eye untreated (treatment was randomly assigned) showed a significant delay in the treated eyes compared with the untreated eyes (paired eye comparison). This suggests that panretinal laser photocoagulation induces a further delay in the b-wave implicit times of eyes treated for diabetic retinopathy.

Adult↗
PubMed1987

Predicting progression to severe proliferative diabetic retinopathy.

The longer-term progression of retinopathy was observed in a previously described group of 85 diabetic patients enrolled in the Early Treatment Diabetic Retinopathy Study. The probability of progression to severe retinopathy was significantly greater for eyes with the following baseline characteristics: greater overall retinopathy severity, higher fluorescein leakage, higher capillary nonperfusion, and lower electroretinographic oscillatory potential amplitudes. The summed amplitudes of the oscillatory potentials, the overall severity of retinopathy, and the severity of fluorescein angiographic leakage were found to be independent predictors of progression to severe proliferative retinopathy in a regression model; capillary nonperfusion was not found to predict progression independently when fluorescein leakage was included in the model. Probability curves based on the regression model can be used to support clinical decisions concerning when to perform panretinal laser photocoagulation and how often to follow up patients with less than severe proliferative diabetic retinopathy.

Adult↗
PubMed1987

Oscillatory potential amplitudes. Relation to severity of diabetic retinopathy.

The oscillatory potentials of the electroretinogram and other visual function tests were evaluated in a group of 174 diabetic and 54 control subjects. Retinopathy severity in diabetic patients was measured in color fundus photographs and fluorescein angiograms. The summed amplitudes of the oscillatory potentials were significantly lower in diabetic compared with control subjects, and the amplitudes decreased progressively as the retinopathy severity increased. Among diabetic patients, a significant correlation was found between the oscillatory potentials and the other visual function tests; lower amplitudes were associated with lower visual field and visual acuity scores and higher Farnsworth-Munsell 100-hue error scores. Stepwise regression analysis showed that the most important predictors of oscillatory potential amplitudes were retinopathy level, fluorescein leakage, and age; capillary nonperfusion did not add to the predictive power of the model when fluorescein leakage was included.

Adult↗
PubMed1986

Diabetic macular edema. A review.

Diabetic macular edema can be classified into a focal variety, characterized by focal leakage from microaneurysms, often with accumulation of extravascular lipoprotein in a circinate pattern around the focal leakage, and a diffuse variety, with diffuse leakage from retinal vessels often accompanied by cystoid macular changes. Laser photocoagulation is directed at microaneurysms for focal leakage and is applied in a grid pattern for diffuse leakage. Several prospective randomized clinical trials have shown that laser-treated eyes fare better than untreated eyes: there is a higher rate of modest visual improvement and a lower rate of visual deterioration in eyes treated with laser photocoagulation. In patients with diabetic macular edema, especially the diffuse variety, systemic factors also may play a pathogenic role. Fluid retention and hypertension due to cardiovascular and renal disease exacerbate retinal capillary leakage. Correction of systemic abnormalities (reduced blood pressure, diuresis) may reduce macular edema and should be included as part of the total management of patients with diabetic macular edema.

Clinical Trials as Topic↗
PubMed1985

Association of hue discrimination loss and diabetic retinopathy.

The results of Farnsworth-Munsell 100-hue, visual acuity, and visual field testing were compared with the severity of retinopathy in a group of 90 diabetic patients. The patients showed significantly higher than expected Farnsworth-Munsell 100-hue scores, with a tritanlike axis, compared with published age norms for nondiabetic individuals. The magnitude of the acquired blue-yellow hue discrimination defect correlated significantly and to a similar extent with both the severity of overall diabetic retinopathy and the severity of macular edema and hard exudate formation. Visual acuity loss correlated somewhat more significantly with macular edema than with overall retinopathy, whereas the converse was true for visual fields. For all visual function tests, the correlations were more significant for fluorescein leakage in the macula than for capillary nonperfusion in the macula. Abnormal hue discrimination was found in 65% (32/49) of eyes with proliferative diabetic retinopathy, suggesting a potential role for this test in screening for proliferative diabetic retinopathy in primary care facilities. Also, because the ability of diabetic patients with color vision deficiency to perform color-dependent tests for urinary and blood glucose may be impaired, such patients should be made aware of this potential problem.

Adult↗
PubMed1985

Karsch-Neugebauer syndrome: split foot/split hand and congenital nystagmus.

A family with four members with split foot/split hand malformations and congenital nystagmus is described. The clinical characteristics in this family correspond to those seen in two other families previously reported. Taken together, these three families suggest that a single, pleiotropic dominant gene is causal. Karsch-Neugebauer syndrome is suggested as an appropriate eponymic designation for this disorder.

Abnormalities, Multiple↗
PubMed1984

Autosomal dominant peripheral preretinal deposits.

Abnormal yellow-white peripheral preretinal deposits are described as an autosomal dominant disorder in ten members of a large pedigree spanning three generations. The absence of any other major vitreoretinal abnormalities or retinal function disorders suggests that this is a benign disease; the nature and origin of the preretinal deposits is obscure.

Electrooculography↗
PubMed1984

Abnormalities of the foveal avascular zone in diabetic retinopathy.

The dimensions of the foveal avascular zone (FAZ) were measured in fluorescein angiograms from 36 diabetic patients and 20 nondiabetic controls. The median values for longest diameter, mean diameter, and circumference were significantly greater in the diabetic group than in the control group. Longest diameters greater than 1.0 mm were found almost exclusively in eyes with proliferative diabetic retinopathy. The FAZ dimensions were strongly positively correlated with the severity of capillary nonperfusion in the posterior retina, but not with fluorescein leakage. The presence of proliferative diabetic retinopathy was also strongly correlated with capillary nonperfusion. Retinal capillary occlusion as the cause of FAZ enlargement in diabetic retinopathy is supported by these findings.

Adult↗
PubMed1984

Electroretinographic oscillatory potentials predict progression of diabetic retinopathy. Preliminary report.

The oscillatory potential (OP) amplitudes of the electroretinogram (ERG) were determined in a group of 85 diabetic patients entering the Early Treatment Diabetic Retinopathy Study (ETDRS). The rate of progression among nonphotocoagulated eyes to the Diabetic Retinopathy Study high-risk characteristics (DRS-HRC) during a ten- to 40-month follow-up period was determined. Progression occurred in 19 of 85 eyes at risk. Those eyes with abnormal OP amplitudes (less than or equal to 75 microV) at study entry had a tenfold higher rate of progression to DRS-HRC than did eyes with normal amplitudes (greater than 75 microV). Although the level of retinopathic severity at study entry was a significant factor in the rate of subsequent progression, the amplitudes of the OPs remained a significant risk factor even after correcting the initial retinopathic level. The ERG seems to be a useful clinical tool in predicting the rate of progression of diabetic retinopathy. The reduction in OP amplitudes probably is a quantitative measure of the degree of overall inner layer retinal ischemia.

Adolescent↗
PubMed1984

Urinary glucose testing inaccuracies among diabetic patients. Effect of acquired color vision deficiency caused by diabetic retinopathy.

The performance of two urinary glucose tests (Clinitest and Diastix) and several color vision and lightness discrimination tests was assessed in 43 diabetic patients and 43 age-matched controls. Most of the diabetics had proliferative diabetic retinopathy, with normal or mildly reduced visual acuity. The diabetics made significantly more errors on color interpretation of the urinary test results than did controls. The extent of errors for both diabetics and controls correlated with the severity of color vision deficiency but not with lightness discrimination deficiency. The diabetics' performance of the Clinitest test and, to a lesser extent, of the Diastix test was significantly better in bright light than in dimmer light. The type of color vision deficiency among most of the diabetics was characteristic of the acquired blue-yellow defect associated with diabetes mellitus. All of the color vision tests enabled identification of patients likely to make a large number of urine-testing errors with high sensitivity and fairly high specificity.

Adult↗
PubMed1983

Butterfly-shaped macular dystrophy in four generations.

Four generations in a family were affected by butterfly-shaped macular dystrophy. Affected members ranged in age from 8 to 77 years. In addition to the primary features of autosomal dominant inheritance, bilateral symmetrical pigmented macular lesion, and a low electrooculographic light peak-dark trough ratio, we discovered additional progressive changes: peripapillary and parafoveal chorioretinal atrophy, enlarged blind spots, and paracentral scotomas with diminished visual acuity late. Because of the progressive change in the ophthalmologic appearance of the fundus, the diagnosis could easily be overlooked in advanced cases.

Adolescent↗
PubMed1983

Diabetic maculopathy. A critical review highlighting diffuse macular edema.

Retinal ischemia and edema are the two major intraretinal components of diabetic maculopathy. Focal macular edema is caused by focal leakage from retinal microaneurysms and dilated capillary segments; diffuse edema is caused by leakage from diffusely dilated retinal capillaries throughout the posterior pole. Diffuse macular edema may be exacerbated by systemic factors such as cardiac or renal failure, and hypertension. It is postulated that dysfunction of the retinal pigment epithelial barrier and transport functions might contribute to the problem of diffuse macular edema. Newer techniques of laser grid photocoagulation for diffuse edema have been proposed. It is postulated that photocoagulative debridement of a disordered retinal pigment epithelium could be a mechanism of action of this treatment.

Adolescent↗
PubMed1982

New visual acuity charts for clinical research.

Three new visual acuity charts facilitate quantitative use of visual acuity test results. The charts have high-contrast lettering on washable white polystyrene. Each line has five Sloan letters; the lines are of equal difficulty and there is a geometric progression in letter size from line to line. This provides a similar task for each line on the chart with the letter size being the only variable. Charts with different letter sequences are used for testing right and left eyes.

Humans↗
PubMed1981

Visual function abnormalities in macular heterotopia caused by proliferative diabetic retinopathy.

In seven patients with displacement of the macula in one eye caused by vitreoretinal traction from proliferative diabetic retinopathy, the macula was displaced toward the optic disk in all but one eye. The eyes with macular heterotopia showed (1) reduced visual acuity (ranging from 6/6 (20/20) to 6/24 (20/80), (2) reduced static perimetry sensitivity (particularly in the temporal field) with displacement of the peak sensitivity toward the blind spot, (3) loss of hue discrimination, and (4) metamorphopsia. In two eyes with macular heterotopia, Stiles-Crawford data provided evidence for photoreceptor disorientation; one eye had mixed orientation, and the other a displaced peak suggesting regular photoreceptor tilting. The proposed mechanisms of visual loss in eyes with macular heterotopia secondary to traction from proliferative diabetic retinopathy include detachment of the macula, disorientation of photoreceptors in the macula, and disturbance of normal neural connections within the retina caused by stretching of the retina.

Adult↗
PubMed1980

Pars plana vitrectomy. Treatment for tractional macula detachment secondary to proliferative diabetic retinopathy.

Pars plana vitrectomies were performed on 43 eyes with traction macular detachment secondary to proliferative diabetic retinopathy. Anatomic success, as judged by reattachment of the macula, occurred 28 (65%) eyes. Improved visual acuity occurred in 11 (26%) eyes. Severe complications occurring after vitrectomy included moderate to severe rubeosis iridis diabetica (28%), neovascular glaucoma (16%), vitreous hemorrhage (49%), and phthisis bulbi (14%). Eyes that received scatter photocagulation therapy at some time prior to macular detachment had a substantially lower incidence of successful postoperative reattachment of the macula than eyes never treated with photocoagulation.

Adolescent↗