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Biomedical subjects

S A Obstbaum

Publications and source records attributed to S A Obstbaum.

At least 19 recordsLinked to original sources
PubMed1992

Lens-induced glaucoma.

The crystalline lens is implicated as a causative element in producing several forms of glaucoma. Etiologically they represent a diversity in the presentation of the glaucomatous process. These conditions include glaucoma related to: lens dislocation (ectopia lentis), lens swelling (intumescent cataract), classical pupillary block, aqueous misdirection--ciliary block, phacoanaphylaxis, lens particle, and phacolytic glaucoma. The management of elevated intraocular pressure often requires altering the intraocular relationship of anatomic structures surrounding the lens or lens removal. We will review the entities that produce these lens-induced glaucomatous conditions and suggest a rational approach to their diagnosis and treatment.

Aqueous Humor↗
PubMed1992

The Binkhorst Medal Lecture. Biologic relationship between poly(methyl methacrylate) intraocular lenses and uveal tissue.

Implantation of a poly(methyl methacrylate) (PMMA) intraocular lens (IOL) after cataract surgery is associated with breakdown of the blood-ocular barrier and a foreign body inflammatory response. Although the material is biocompatible, it is not inert. The history of PMMA IOL implantation has reflected mechanical, chemical, and immunological interactions between the IOL and ocular tissues. The common link in these events is instability of the blood-ocular barrier. In this lecture, I discuss the nature of these interactions and present evidence that currently investigated methods of surface modification and capsular bag IOL implantation are effective in stabilizing the blood-ocular barrier.

Animals↗
PubMed1991

Stability of refraction during four years after radial keratotomy in the prospective evaluation of radial keratotomy study.

The Prospective Evaluation of Radial Keratotomy Study is a nine-center clinical trial of a standardized technique of radial keratotomy in 435 patients who had simple myopia with a preoperative refraction between -2.00 and -8.00 diopters. We studied the stability of the refractive error during four years after surgery for each of 341 eyes first operated on that had a single surgical procedure. Between baseline and two weeks after surgery, all eyes became less myopic; between two weeks and three months, 161 eyes (59%) lost 1.00 D or more of the initial effect; and between three and six months, 266 eyes (95%) had a stable refraction with less than 1.00 D change. The change from six months to four years was less than 1.00 D for 246 eyes (72%). There was 1.00 D or more decrease in surgical effect (increased minus power) for 13 eyes (4%), and 1.00 D or more increase in surgical effect (decreased minus power) for 82 eyes (24%). Eyes with larger amounts of preoperative myopia and smaller diameter of the clear zone were more likely to have an increasing effect of the surgery. The duration of this continued increasing effect of the surgery is unknown.

Adult↗
PubMed1979

Cataract extraction in glaucoma.

Cyclodialysis lens extraction or cyclodialysis canalicular trabeculectomy lens extraction in one eye and cataract extraction in the fellow eye were performed in 24 glaucoma patients. The combined procedure follow-up was from five to 12 years in the first group, two to four years in the second group, and from three to ten years in the control group. The 50% success rate of cyclodialysis lens extraction can be enhanced with no significant increase in surgical morbidity or postoperative complications by performing a cyclodialysis canalicular trabeculectomy where the disinsertion of the scleral spur is carried out under direct visualization.

Aged↗
PubMed1979

The effects of timolol on cataract extraction and intraocular pressure.

We studied the effect of timolol on post-operative intraocular pressures (IOPs) in a control and experimental group of 30 eyes, each in patients who had uncomplicated intracapsular cataract extractions, most with iris clip lenses. Closure of the eye in each case was with three 6-0 silk sutures preplaced in a morticed incision. Six control eyes had IOP increases of 6 mm Hg or more within 24 hours of surgery. One patient treated with timolol had an IOP increase of 6 mm Hg or more. The differences in IOP between the control and experimental groups were statistically significant at the .01 level. The pressure lowering ability of timolol appears to be prophylactic as well as therapeutic. It is well suited for pseudophakic eyes as pressure reduction is not associated with pupillary alterations.

Cataract Extraction↗
PubMed1979

Retinal detachment in pseudophakia.

In a series of cataract patients excluding myopic individuals, under age 60 years, and cases in which vitreous loss occurred, retinal detachment was no less frequent after intracapsular cataract extraction and Sputnik iris supported lenses than in controls. Both groups were followed up for a minimum of two years. The detachments predominantly occurred from retinal breaks in areas of the retina that looked normal preoperatively.

Age Factors↗
PubMed1979

Time analysis of corneal endothelial cell density after cataract extraction.

Serial endothelial photographs were taken preoperatively and postoperatively in 200 eyes; 111 eyes contained a Rayner iris clip lens, 54 eyes contained a Fyodorov Sputnik lens, and 35 eyes had no lens. Central endothelial cell density was changed in all instances, with counts in implanted eyes declining 25 to 30%, and in nonimplanted eyes 10 to 15%. In both instances, the decline essentially ceased at about three months. The cause of the greater decline in implanted eyes appeared to be mechanical and subsequent cell loss after the 90-day period was virtually equal for the two groups. Methods that may be used to alter the difference in cell density occurring with implantation are best analyzed by using the 90-day period data for comparison.

Animals↗
PubMed1979

Cystoid macular oedema and ocular inflammation. The corneo-retinal inflammatory syndrome.

Intraocular lens implantation may be associated with an inflammatory syndrome which leads to corneal decompensation and cystoid macular oedema. The inflammatory aspects often do not appear striking but manifest as mild ciliary flush, mild flare, moderate cells in the anterior chamber, and moderate vitritis. The cornea will decompensate in the presence of endothelial cell counts which are sufficient to maintain corneal clarity in the non-inflamed eye. Metal-looped lenses and poorly polished lenses cause iris chafing and capillary leakage which increase the severity of this syndrome. It is postulated that intraocular surgery initiates an inflammatory response which is augmented by certain components of intraocular lenses. The mediation for this increased inflammatory response may be inhibited by both steroidal and non-steroidal anti-inflammatory agents. The presence of white blood cells and their products, such as lysosomal enzymes, may be sufficient to perpetuate the inflammatory response and cause damage to abnormal and normal cells. The presence of protein and its immune components, as well as complement, may be involved in this syndrome.

Aged↗
PubMed1978

Trimolol: effect on intraocular pressure in chronic open-angle glaucoma.

Timolol maleate is an effective agent of reducing intraocular pressure in patients with chronic open-angle glaucoma. To date, there are no adverse side effects demonstrable with use of this medication. Its mechanism of action is not clearly delineated but preliminary data suggest an effect on outflow facility.

Adrenergic beta-Antagonists↗
PubMed1977

Iris-supported lens implantation v. simple cataract extraction. An analysis of data.

In a study of a selected age (greater than 60) and ocularly matched population requiring cataract extraction, a perfectly executed intracapsular cataract extraction followed by the introduction of a Fyodorov Type II ("Sputnik") lens did not lead to irreversible anterior or posterior segment changes different from those seen in a group followed for from 5 to 9 years. It did lead to an incidence of implant support dislocation and to membrane formation in about 10% of cases, reducible to about 2% with correctly made lenses and the appropriate use of postoperative drugs. The incidence of corneal degeneration (0), retinal detachment (2%), and intraretinal cystic maculopathy (3%) was equal in each group. Visual acuity levels were also equal. In appropriate cases, if the surgery is carried out with sufficient skill, the reward to risk ratio of implantation not only justifies but indicates the use of such lenses.

Aged↗
PubMed1976

Topical epinephrine and cystoid macular edema.

Epinephrine maculopathy occurred in one eye of a patient that spontaneously developed intraretinal cystic maculopathy in the other eye. The clinical and fluorescein angiographic apperance of the two conditions were identical. It is likely that the two conditions have a common organic denominator.

Administration, Topical↗