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Biomedical subjects

B Streeten

Publications and source records attributed to B Streeten.

6 recordsLinked to original sources

The anterior capsulotomy of extracapsular cataract extraction.

Cataracts are a major cause of blindness, and more than 75% of all cataract operations performed in the United States are associated with an intraocular lens (IOL) implant. Since approximately 63% of all IOL implants are of the posterior chamber type and associated with extracapsular cataract extraction (ECCE), it is important for the ophthalmic surgeon to perfect this operation. We describe herein the important surgical anatomy of the zonular-lens capsular attachments and present the results of a poll of experts as to the important aspects of the anterior capsulotomy of the ECCE.

Adolescent↗

Argon laser iridotomy on primary angle closure or pupillary block glaucoma.

Scanning and transmission electron microscopy were performed on peripheral iridectomy specimens from seven patients with failed pulsed argon laser iridotomies. Four to seven hours after the laser, severe edema, coagulation necrosis, focal vascular occlusion, and hemorrhage were present. Five days after the laser, cell detritus and collapsed cell processes were noted. Forty-two days after the laser, the anterior iris surface appeared considerably thinned and irregular. Eight and one-half months after the laser, the burn site displayed a dense matted appearance. Two years after the laser, the anterior iris showed a depression with pigment dispersion, irregular stroma, and disruption of the dilator muscle. The lack of inflammation could be due to the use of pulsed argon laser heat delivered at very short intervals, with deep penetration and minimal heat dispersion, since the beam is highly collimated.

Follow-Up Studies↗

Argon laser iridotomy in the treatment of patients with primary angle-closure or pupillary block glaucoma: a clinicopathologic study.

A "pulsed" argon laser was successful in 48 of 64 (75%) attempted laser iridotomies. Scanning and transmission electron microscopy performed on specimens taken at varying intervals following laser treatment revealed progressive scarring of iris tissue. The complications appear minimal at this time, but longer follow-up is required before it can be stated that laser and surgical peripheral iridectomies are comparable. However, the laser's simplicity and ease of administration appear to warrant its continued use at this time.

Argon↗

Corneal opacification occurring after phacoemulsification and phacofragmentation.

Four patients developed progressive corneal opacification five to eight months after ultrasonic cataract extraction. Transmission electron microscopy was performed in all patients. Scanning electron microscopy, performed in only one patient, showed radiating folds of Descemet's membrane with pits on its posterior surface as well as focal traumatic disruption probably caused by probe contact. Bullous keratopathy was present in one patient. Two other patients had folds of Descemet's membrane and a thin retrocorneal fibrous layer. All four tumor specimens showed secondary epithelial and stromal changes. The common denominator was the total or partial absence of endothelium or marked alterations of its remnants.

Aged↗

Vitreous membranes. A light and electron microscopical study.

Patients with pigmented vitreous membranes were subjected to partial vitrectomy, and the membranes were studied by light and electron microscopy. Two yellow ochre membranes from eyes removed at autopsy were also examined. The membranes were composed of degenerating red cells and a delicate matrix of collagen. Phagocytic cells of uncertain origin and migrating retinal pigment epithelial cells were present in some of the membranes. Vascular channels were observed in only two cases, in which the membranes had clinical features different from those in the remaining cases. The development of new techniques of vitrectomy and the relatively normal clinical appearance of the posterior pole of the retina in these cases both suggest the potential clinical value of vitreous membrane excision. Additional histopathologic studies of vitrectomy specimens will enhance our understanding of the indications for this procedure.

Adult↗