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Biomedical subjects

R C Watzke

Publications and source records attributed to R C Watzke.

At least 19 recordsLinked to original sources
PubMed1992

A model for the apparent decrease in optical transmittance of the diabetic eye.

This paper compares observed changes of ocular transmittance at short and long wavelengths in diabetic patients with values predicted by a model based on the Rayleigh light scattering properties of albumin. Selective chromatic adaptation was used to obtain critical flicker fusion (CFF) frequency thresholds from 21 subjects and 18 patients with insulin-dependent diabetes. The Ferry-Porter characteristic of each color-sensitive mechanism of each patient was compared to age-specific control values. For those eyes without an indication of neural injury, changes in optical density associated with the red- and blue-sensitive mechanisms were calculated and adjusted to reflect accelerated yellowing of the lens produced by increased duration of diabetes. The range of concentration of glycosylated albumin required to fit the model to the adjusted short-wavelength changes in optical density was determined and used to calculate the theoretical long-wavelength changes in optical density. The experimentally derived long-wavelength changes in optical density fell within the 95% confidence level of the values described by the model. These results support the premise that the apparent decrease in optical transmittance observed in patients with diabetes mellitus is caused by light scattering produced by dilute increase of plasma proteins within the retina.

Adaptation, Ocular↗
PubMed1991

Acute idiopathic blind spot enlargement. A spectrum of disease.

The authors present a report on their experience with 10 patients with acute idiopathic blind spot enlargement. All had enlarged steep-margined blind spots without accompanying changes in optic disc appearance, significantly diminished visual acuity or color vision. Fluorescein angiography was obtained in eight patients. Five patients had retinal appearance that was either normal or could not be attributed to a known disease entity. Three patients had the multiple evanescent white dot syndrome, one had acute macular neuroretinopathy, and at least one had presumed ocular histoplasmosis. It has been proposed that acute idiopathic blind spot enlargement is a subset of multiple evanescent white dot syndrome. The authors' findings suggest that multiple evanescent white dot syndrome and other retinal diseases, some not yet identified, are subsets of acute idiopathic blind spot enlargement.

Acute Disease↗
PubMed1991

Retinal vasculitis--a primer.

Retinal vasculitis is a diagnosis that is generally suggested by an ophthalmologist. Frequently patients with the disorder are referred to nonophthalmologists for further diagnostic evaluation or treatment. The criteria for defining vasculitis differ greatly between ophthalmologists and other physicians. To facilitate collaboration between ophthalmologists and their colleagues, we have sought to clarify the term "retinal vasculitis" by discussing its subcategories, the potential role of antiphospholipid antibodies, and the etiology of retinal vasculitis. We offer guidelines for evaluating the disorder and treating patients.

Humans↗
PubMed1990

Photographic grading in the retinopathy of prematurity cryotherapy trial.

We report a system for photographic grading of the posterior fundus features of retinopathy of prematurity and correlation of such features with potential future visual function. The severity of temporal vessel traction, retinal fold, macular ectopia, retinal detachment, retrolental mass, blood vessel attenuation, retinal pigment epithelial scarring, and cataract was assessed by review of photographs at the Fundus Photograph Reading Center, Portland, Ore, according to a scheme designed to avoid bias or knowledge of treatment status. Reliability for all features was in the fair to excellent range (kappa greater than .40), except for blood vessel attenuation (kappa = .18), which was not a factor in the final outcome determination. The grading scheme provided the basis for the 3-month conclusions of the multicenter trial of cryotherapy for retinopathy of prematurity. This system will have further application in the 12-month Cryotherapy for Retinopathy of Prematurity Study conclusions and in future long-term correlation with visual acuity as the trial patients mature.

Cataract↗
PubMed1989

Growth features of choroidal neovascular membranes in age-related macular degeneration.

The authors studied 80 eyes of patients with choroidal neovascular membranes (CNVMs) associated with age-related macular degeneration between 1982 and 1988. In each case, fluorescein angiography was done on two occasions separated by an interval of 2 days to 11 weeks (average, 13 days) without intervening photocoagulation. Forty-three CNVMs (54%) grew toward the fovea during the interval between fluorescein angiograms, with growth rates ranging from 1 to 24 microns daily (average, 10 microns daily). The CNVM growth was related to the time interval between angiograms (P less than 0.0001), but was not associated with morphologic features of the CNVM. These results reinforce the need for early detection and prompt evaluation of elderly patients with symptoms of CNVMs.

Aged↗
PubMed1988

Results and complications of pneumatic retinopexy.

Fifty-one patients with primary rhegmatogenous retinal detachment (RD) were treated by pneumatic retinopexy. The overall success rate for reattachment with one operation was 63%. Of the 34 phakic eyes, 25 (74%) were reattached; of the 17 aphakic or pseudophakic eyes, seven (41%) were reattached (P less than 0.05). Postoperative complications included the development of new tears (22%), inadequate closure of the original tear, shifting and delayed absorption of subretinal fluid, and opening of previously closed tears. Pneumatic retinopexy is a valuable new technique; however, careful patient selection and postoperative management is required.

Aged↗
PubMed1986

Abnormal glucose metabolism and parafoveal telangiectasia.

Parafoveal telangiectasia is a microvascular abnormality of the macula that may be developmental or acquired. Twenty-eight patients with this condition and normal fasting blood glucose levels underwent ophthalmologic evaluation and glucose tolerance testing. Bilateral telangiectasia was more frequently associated with laboratory evidence of abnormal glucose metabolism than unilateral disease (five of eight cases vs six of 17 cases). In five of our patients, results of glucose tolerance testing were consistent with diabetes even though fasting blood glucose levels were normal. Right-angle venules, which have been reported to be an important sign of bilateral disease, were also found in unilateral telangiectasia. Unilateral telangiectasia occurs in females as well as males. Glucose tolerance testing should be performed in all patients who have bilateral parafoveal telangiectasia.

Adult↗
PubMed1979

Direct and indirect laser photocoagulation of central serous choroidopathy.

A 3 1/2-year prospective randomized clinical trial showed a definite superiority of direct argon laser photocoagulation to the fluorescein leaking site compared to indirect treatment away from the leak in patients with central serous choroidopathy. One patient in each treatment group developed a subretinal neovascular membrane after photocoagulation to the fluorescein leak. Moderate prolongation of the neurosensory detachment did not adversely influence the final visual acuity in the indirect treatment group. Although direct laser photocoagulation reduces the duration of central serous choroidopathy, there is a risk of producing subretinal neovascularization. The principles of risk vs benefit should be explained to all patients and treatment should be advised only for compelling reasons.

Adolescent↗
PubMed1977

Bilateral choroidal melanomas. Case report and incidence.

A 55-year-old woman had bilateral choroidal melanoma. To our knowledge, this is the second reported case in the United States. To calculate the incidence of bilateral cases, we determined the incidence of unilateral choroidal and ciliary body melanomas among the white population in Iowa. We also studied the incidence of these melanomas by different age and sex groups. One of 2,500 whites will develop a choroidal melanoma during his or her lifetime. Based on these values and those of life expectancy in patients harboring a choroidal melanoma, we calculated the risks of developing a second primary melanoma in the other eye. In a population of 50 million whites, 1 person will develop a bilateral choroidal melanoma during his or her lifetime. In other words, a bilateral case is expected to occur once every 18 years in the United States.

Age Factors↗
PubMed1976

Retinal vascular changes of incontinentia pigmenti.

Of 19 patients with incontinentia pigmenti, seven had a bizarre retinal anomaly that consisted of a zone of abnormal arteriovenous connections and preretinal fibrotic tissue at the temporal equator, with no perfusion peripheral to it. In one patient, the vascular changes progressed and required photocoagulation. This retinal lesion may represent an early stage of the pseudoglioma that so commonly is reported with this skin disease. Incontinentia pigmenti should be considered in the differential diagnosis of retinal vascular disease in girls and women of any age.

Adolescent↗
PubMed1975

Retinal hemorrhages in posterior vitreous detachment.

Detachment of the posterior vitreous can cause clinically significant retinal hemorrhage. Two patients with acute posterior vitreous detachment had massive retinal hemorrhages overlying the optic disks. These absorbed in time without sequealae. A third patient had numerous small blot hemorrhages scattered near the optic disk and macula. A fourth patient presented with a small macular hemorrhage causing temporary visual loss. All patients had moderately severe myopia and were in good health without hypertension or diabetes. There was no history of trauma or Valsalva maneuver. Hematologic and coagulation studies were normal. These cases indicate that retinal hemorrhages due to posterior vitreous detachment may be strikingly large, multiple, and, when involving the macula, cause temporary visual loss.

Adult↗