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Biomedical subjects

R Ritch

Publications and source records attributed to R Ritch.

At least 199 records · Page 11Linked to original sources
PubMed1991

Tears of the retinal pigment epithelium: occurrence in association with choroidal effusion.

Two patients developed large tears of the retinal pigment epithelium associated with choroidal effusion. One tear occurred after combined cataract/filtration surgery complicated by postoperative choroidal detachment; the second developed in a patient with idiopathic uveal effusion syndrome. Weakness of the junctions of the pigment epithelial cells secondary to the accumulation of fluid in the subretinal or suprachoroidal space may result in tearing of the retinal pigment epithelium as it is stretched.

Aged↗
PubMed1991

5 alpha-dihydrocortisol in human aqueous humor and metabolism of cortisol by human lenses in vitro.

Glucocorticoids have long been implicated in the etiology of primary open-angle glaucoma (POAG) and cataract. Cortisol metabolites have biologic activity and may affect aqueous humor dynamics. This study was done to determine whether these metabolites are found in human aqueous humor and can be produced by ocular tissues. Radioimmunoassays (RIA) were developed for 5 alpha-dihydrocortisol (5 alpha-DHF) and 5 beta-dihydrocortisol (5 beta-DHF). These assays, as well as a cortisol RIA, were used to quantify these three steroids in 20 surgically derived aqueous humor specimens from patients with and without POAG. The mean concentrations of cortisol and 5 alpha-DHF were 2.5 and 1.3 ng/ml, respectively. In the small group studied, there was no statistically significant difference between the aqueous humor steroid levels in patients with and without POAG. The amount of 5 beta-DHF was at the lower limits of detection of the assay system and could not be uniquivocally shown. Human lenses metabolized cortisol in vitro to 5 alpha-DHF and 3 alpha,5 alpha-tetrahydrocortisol (3 alpha,5 alpha-THF). There was no 5 beta-DHF or cortisone formed. The 5 alpha-DHF and 3 alpha,5 alpha-THF were identified by their positions on thin-layer chromatography, their retention times on high-performance liquid chromatography, and recrystallization with authentic standards to constant specific activity. The data suggest that the lens is the source of 5 alpha-DHF in aqueous humor.

Aged↗
PubMed1990

Combined exfoliation and pigment dispersion syndrome.

Both exfoliation syndrome and pigmentary dispersion syndrome can lead to secondary glaucoma. We treated five patients who had pigmentary dispersion and who subsequently developed exfoliation. In one patient who had bilateral pigment dispersion syndrome, the presence of exfoliation increased the difficulty of controlling intraocular pressure in the affected eye. In a monocular patient, exfoliation and pigmentary dispersion were concurrently present with characteristic defects of both pigmentary dispersion and exfoliation as seen by transillumination defects of the iris. A third patient had bilateral pigmentary dispersion and uncontrollable intraocular pressure in an eye with exfoliation. Despite argon laser trabeculoplasty, the pressure remained uncontrolled. Another patient had a filtering operation in the left eye, with gradually increasing intraocular pressure in the right eye. Exfoliation material complicated the pressure control in the unoperated on eye. Another patient had an eight-year history of glaucoma in the left eye for which filtering surgery was performed. Exfoliation was present in both eyes with controlled pressure in the filtered eye but uncontrolled pressure in the nonfiltered eye.

Anterior Eye Segment↗
PubMed1990

Ocular findings in oculodermal melanocytosis.

We examined 194 patients with oculodermal melanocytosis. Dermal involvement alone was present in 67 (34.5%) patients, while 12 (6.2%) had only ocular involvement. The remaining 115 (59.3%) patients had both ocular and dermal pigmentation. Dermal hyperpigmentation in the combined distribution of the ophthalmic and maxillary divisions of the trigeminal nerve and hyperpigmentation of the nasal or buccal mucosa were closely associated with ocular involvement. Ocular hyperpigmentation most commonly involved the episclera. Associated ocular findings included elevated intraocular pressure with or without glaucoma (10.3%), uveitis (2.6%), cataract (1%), asymmetric cupping of the optic nerve head unassociated with glaucoma (9.8%), and orbital melanoma (0.5%). The most serious complication of oculodermal melanocytosis is malignant transformation, while glaucoma appears to be the more common one. Patients with oculodermal melanocytosis and ocular hyperpigmentation should be followed up at regular intervals for the development of either of these complications.

Adolescent↗
PubMed1990

Early intraocular pressure rise after trabeculectomy.

Intraocular pressure (IOP) was measured 4 to 6 hours after surgery and on the first postoperative day in 35 eyes of 35 consecutive patients undergoing initial trabeculectomy. In 27 eyes, the anterior chamber was re-formed at the completion of surgery with balanced salt solution, and in eight eyes it was reformed with hyaluronate sodium. A total of six eyes (17%) had an IOP of 40 mm Hg or greater 4 to 6 hours after surgery. Patients who received hyaluronate to maintain the depth of the anterior chamber had a significantly greater chance of experiencing a marked postoperative IOP rise, both at 4 to 6 hours (P = .005) and on the first postoperative day (P = .0038). There was no correlation between the postoperative IOP rise and the patient's age, sex, glaucoma diagnosis, preoperative IOP, use of 5-fluorouracil, or the number of sutures used to close the scleral flap. Hyaluronate may contribute to an early increase in IOP that could result in further visual field loss in eyes with severe glaucomatous damage. We recommend early monitoring of IOP after trabeculectomy and avoiding the routine use of hyaluronate.

Acetates↗
PubMed1990

Antibodies to Epstein-Barr virus in iridocorneal endothelial syndrome.

Antibody titers to Epstein-Barr virus were determined in 13 patients with iridocorneal endothelial syndrome and in 13 healthy race-, age-, and sex-matched controls. Both the geometric mean titer of IgG antibodies to the Epstein-Barr virus capsid antigen and the proportion with high titers of IgG antibodies to the Epstein-Barr virus capsid antigen (greater than or equal to 1:640) were significantly higher in 12 seropositive patients with iridocorneal endothelial syndrome than in 12 seropositive controls (1/761:1/202, P = .001; 83.3%:8.3%, P less than .001). Ten of 12 seropositive patients with iridocorneal endothelial syndrome and five of 12 seropositive controls had antibodies to Epstein-Barr virus-induced early antigens (greater than or equal to 1:10) (Fisher's Exact Test, P less than .05), while four seropositive patients with iridocorneal endothelial syndrome and one seropositive control had low to undetectable levels of antibodies to Epstein-Barr virus-associated nuclear antigen (less than or equal to 1:5) (P greater than .1). Antibody levels to cytomegalovirus or measles virus were not different between patients with iridocorneal endothelial syndrome and controls. Additional studies showed no evidence of humoral immune disorder or collagen vascular disease in the patients with iridocorneal endothelial syndrome. The serologic profiles suggest that the patients with iridocorneal endothelial syndrome examined had a cellular immune abnormality sufficient to permit reactivation of latent Epstein-Barr virus infection and imply, but do not establish, a role for Epstein-Barr virus infection in the pathogenesis of some cases of the iridocorneal endothelial syndrome.

Adult↗
PubMed1990

Glaucoma in oculodermal melanocytosis.

Oculodermal melanocytosis (ODM) is a developmental disorder of the embryonic neural crest involving virtually all of the structures of the eye derived from this tissue. The authors examined 194 previously unreported Thai patients with ODM. Elevated intraocular pressures (IOPs) developed in the ipsilateral eye of 15 patients at initial examination and in 5 others during follow-up, for a total of 10.3% of the patients. Three patients had congenital or late congenital glaucoma, 14 had ocular hypertension or open-angle glaucoma, and 3 had acute angle-closure glaucoma. Five of the patients with open angles had acute pressure rises accompanied by anterior uveitis. Melanocytic hyperpigmentation of the anterior chamber angle was extensive in all patients except those with acute angle-closure glaucoma. There was no consistent correlation between the extent or density of angle pigmentation and the development of elevated IOP. A larger cup-to-disc ratio in the involved eye, presumably congenital, was present in an additional 19 patients. Glaucoma is common in eyes with ODM and may develop at any age. Patients with ODM and initially normal IOP should be examined at regular intervals. Patients with open angles and acutely elevated IOP should be examined carefully for signs of anterior uveitis and treated medically.

Adolescent↗
PubMed1990

Acute angle-closure glaucoma in a patient with acquired immunodeficiency syndrome successfully treated with argon laser peripheral iridoplasty.

Laser iridectomy relieves pupillary block and is the procedure of choice for angle-closure glaucoma. Since not all cases of angle closure glaucoma are due to this mechanism, iridectomy is not always curative. Argon laser peripheral iridoplasty causes a contraction of peripheral iris away from the trabecular meshwork, and is useful in these circumstances. We successfully treated bilateral acute angle-closure glaucoma in a patient with acquired immunodeficiency syndrome with this procedure.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Juvenile glaucoma, race, and refraction.

Of 68 patients who presented between the ages of 10 and 35 years with elevated intraocular pressure, 25 were classified as juvenile ocular hypertension and 43 as juvenile primary open-angle glaucoma. Blacks constituted a greater proportion of the primary open-angle glaucoma patients (47%) than of the ocular hypertensives (20%) and in both groups presented at younger ages than did whites. Myopia was present in 59% of the ocular hypertensives and 73% of the primary open-angle glaucoma patients, of whom 39% had more than 6 diopters of myopia. All eyes of black patients with more than 3 diopters of myopia had glaucomatous defects compared with 52% of such eyes of white patients. Our data suggest that myopia is strongly associated with juvenile open-angle glaucoma and that young black patients with elevated intraocular pressure, especially when myopic, are more susceptible to glaucomatous damage than are whites.

Adolescent↗
PubMed1989

Racial differences in optic nerve head parameters.

Results of previous studies have strongly indicated that the prevalence of elevated intraocular pressure is greater in blacks than in whites and that blacks are more susceptible than whites to glaucomatous damage at any given level of pressure. It has also been suggested that a larger disc area might predispose an eye to glaucomatous damage. We investigated the possibility that clinically quantifiable differences might exist in optic disc parameters between normotensive white and black patients. Disc area, cup-to-disc ratio, and cup volume measured with a video-ophthalmograph (Rodenstock Optic Disc Analyzer) were significantly larger in blacks than in whites, while there was no difference in the disc rim area between the two groups. We derived a mathematical model of the optic disc that relates posterior displacement of the lamina cribrosa to the disc area, distensibility of the disc, and intraocular pressure.

Adolescent↗
PubMed1989

A modification of the use of the glaucoma tamponade shell.

Filtering surgery may be complicated by excessive filtration or bleb leak in the postoperative period, resulting in a shallow or flat anterior chamber and choroidal detachment. A glaucoma tamponade shell with a raised inner platform increases the resistance to flow through the fistula, deepening the anterior chamber. Some surgeons apply a pressure patch over the shell to increase the tamponading effect and to prevent rotation of the shell. Nevertheless, the shell may still rotate, resulting in less than adequate tamponade. We describe a technique that prevents rotation of the shell.

Bandages↗
PubMed1989

S (blue) cone pathway vulnerability in retinitis pigmentosa, diabetes and glaucoma.

A variety of retinal disease lead to a decrease in the sensitivity of the S (blue) cone pathways. To determine the possible sites and mechanisms of this loss we compared the sensitivities of an S (blue/pi-1) and an M (green/pi-4) cone pathway in patients with retinal diseases that differ as to their primary locus of sensitivity loss. The sensitivities of an S and an M cone pathway were assessed in patients with retinitis pigmentosa, insulin-dependent diabetes mellitus and open-angle glaucoma using Stiles two-color increment threshold technique. A greater loss in sensitivity of an S than an M cone pathway was found for all three disease groups; however, the diabetic patients showed a more selective loss. The results suggest that multiple sites are involved and that the combined effects of metabolic abnormalities and hypoxia contribute to the selective loss.

Adaptation, Ocular↗
PubMed1988

A long Krupin-Denver valve implant attached to a 180 degrees scleral explant for glaucoma surgery.

A long glaucoma valve implant attached to an external scleral explant was used during filtration surgery in 72 eyes: 39 eyes with neovascular glaucoma and 33 eyes with other types of secondary glaucomas or with primary glaucoma in which prior filtration surgery had failed. The implant consisted of an open Silastic tube (outside diameter, 0.64 mm), which was placed into the anterior chamber. The external end of the tube contained a pressure-sensitive (opening pressure, 11 mmHg) and unidirectional slit-valve, and was sutured within the groove of a #220 Silastic explant. The 180 degree explant was placed beneath three rectus muscles and then sutured so that the grooved side was against the sclera, with the anterior edge 8 to 12 mm posterior to the limbus. The long glaucoma valve implant resulted in a large, posterior bleb extending over the area of the Silastic explant. The mean preoperative intraocular pressure (IOP) of 43.9 mmHg in the eyes with neovascular glaucoma was reduced to 17.4 mmHg after a mean follow-up of 20.2 months. The mean preoperative IOP of 38.1 mmHg in the eyes after failure of previous filtration surgery was reduced to 17.6 mmHg at a mean follow-up of 21.0 months. Postoperative IOP was less than 21 mmHg in 77% of eyes with neovascular glaucoma (47% required additional medication) and in 82% of eyes with previous failure of filtration surgery (56% required additional medication).

Adolescent↗
PubMed1988

Ocular sparganosis: a cause of subconjunctival tumor and deafness.

We report a patient with a subconjunctival mass lesion caused by a larva of Spirometra sp. The parasite, 44 cm long and 1.0 mm wide, was removed intact and alive with complete preservation of the patient's vision. The mode of infection was probably through consumption of contaminated drinking water.

Animals↗
PubMed1987

Preclinical diagnosis of pseudoexfoliation syndrome.

Although the diagnosis of pseudoexfoliation syndrome (PXS) is made by observation of pseudoexfoliation material (PXM) deposited on the anterior lens capsule, there are several additional signs related to pigment dispersion that are often present both in eyes with PXS and fellow eyes in unilateral cases. On the basis of the presence of these signs, we have categorized a group of patients as "pseudoexfoliation suspects" who demonstrated no evidence of PXM on the lens capsule in either eye. As PXM has previously been identified in the conjunctiva of affected eyes as well as fellow eyes in unilateral cases, we hypothesized that it could also be present in PXS suspect eyes. Inferior bulbar conjunctival biopsies were performed on four eyes with PXS, five fellow eyes, and 23 PXS suspect eyes, and specimens were examined by transmission electron microscopy. In eight PXS suspect eyes biopsy specimens demonstrated PXM, suggesting that PXS is more prevalent and possibly responsible for a greater proportion of glaucoma than previously suspected.

Aged↗