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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↗
PubMed1991

Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study five years after surgery. The Perk Study Group.

In the Prospective Evaluation of Radial Keratotomy (PERK) Study, 793 eyes of 435 patients with 2 to 8 diopters (D) of myopia received a standardized surgery consisting of 8 incisions with a diamond-bladed knife set at 100% of the thinnest paracentral ultrasonic corneal thickness measurement and a diameter of the clear zone of 3.0 to 4.5 mm; 97 eyes (12%) received an additional 8 incisions. There were 757 eyes (95%) followed for 3 to 6.3 years. After surgery, uncorrected visual acuity was 20/40 or better in 88% of eyes. The refractive error was within 1 D of emmetropia for 64% of eyes; 19% were myopic and 17% were hyperopic by more than 1 D. Between 6 months and 5 years after surgery, 22% of the eyes had a refractive change of 1 D or more in the hyperopic direction. For 25 eyes (3%) there was a loss of 2 or more lines of best spectacle-corrected visual acuity.

Adult↗
PubMed1989

Posterior chamber intraocular lens dislocations and malpositions.

Decentration and malposition of posterior chamber intraocular lenses (PC IOL) accounts for one of the remaining and unresolved conditions associated with the implantation of these lenses. This condition assumes importance since in approximately 50% of cases where a PC IOL is removed there is an aspect of improper positioning. The common types of malpositions are: pupil capture; sunset syndrome; sunrise syndrome; horizontal decentration; and the windshield wiper syndrome. This paper will explore the causes and management of these conditions and discuss the virtues of capsular bag implantation.

Eye Diseases↗