Long-term follow-up of leiske closed-loop anterior chamber intraocular lenses.

PURPOSE: To provide long-term follow-up on the rates of endothelial cell loss in eyes with retained closed-loop anterior chamber intraocular lenses (IOLs). SETTING: Private practices, Chicago, Illinois, USA. METHODS: In 1980 to 1982, 3 surgeons performed 587 intracapsular cataract extractions with implantation of Leiske closed-loop anterior chamber IOLs. During the prospective part of the study from 1991 to 1996, 59 patients with 83 eligible eyes were followed using specular microscopy and pachymetry. The mean follow-up of the prospective study was 41.9 months, or 12.9 years from the original cataract surgery. RESULTS: No specific preoperative or postoperative factor except the behavior of the fellow eye (P =.022) predicted the rate of endothelial cell loss. During the prospective study, 6 patients required IOL exchange and corneal transplantation. The rate of corneal decompensation was heavily dependent on the initial measurement of endothelial cell density. Corneas with initial endothelial cell counts greater than 1000 cells/mm(2) had a decompensation rate of 1.5%, and corneas with counts of 500 cells/mm(2) or less had a decompensation rate of 57.1% (P <.01). CONCLUSIONS: Clinical examination and serial measurements of endothelial cell density provide the most reliable methods for monitoring patients with closed-loop anterior chamber IOLs. Endothelial cell counts can predict the rate of corneal decompensation. Patients with endothelial cell counts greater than 1000 cells/mm(2) usually do not require an IOL exchange.

An elevated hematogenous photosensitizer in the preterm neonate.

PURPOSE: Human blood contains low levels of protoporphyrin IX (PP IX), a photoactive compound that produces reactive oxygen species when exposed to light. It has been proposed that photoactivation of PP IX and subsequent generation of potentially tissue-damaging reactive oxygen may be a mechanism of retinal injury in retinopathy of prematurity (ROP). The purpose of this study is to determine an association between blood PP IX level and infant birth-weight and gestational age. METHODS: Erythrocyte PP IX levels were measured from the umbilical cord blood of 31 neonates, both full term and preterm. Birthweights and gestational ages were recorded. RESULTS: PP IX levels in infants weighing < 1000 grams (n = 7) average 200 micrograms/dl, which is significantly higher than PP IX levels in infants weighing > 1000 grams (125 micrograms/dl, n = 24; P < 0.02). CONCLUSION: Elevated PP IX levels may place preterm neonates at increased risk for photosensitizing retinal injury.

Surgical management of subluxed posterior-chamber intraocular lenses.

OBJECTIVE: To formulate a systematic approach to the surgical management of subluxed posterior-chamber intraocular lenses (IOLs). DESIGN: We reviewed the records of 31 consecutive patients who underwent anterior-segment surgery for IOL subluxation. Presumed anatomic causes of IOL subluxation were identified in 28 cases (90%). Three surgical procedures were used to correct the implant subluxation: modified McCannel sutures (19 eyes), IOL exchange (eight eyes), or IOL rotation (four eyes). RESULTS: Twenty-nine (94%) of the 31 patients obtained a postoperative visual acuity of 20/40 or better. Surgical complications included persistent vitreous in the anterior chamber (three cases), progressive capsular opacification (two cases), and anterior chamber and vitreous hemorrhage (one case). CONCLUSIONS: Our results show that, by implementing a planned surgical approach, subluxed posterior-chamber IOLs can be safely and effectively managed.

Excision of limbal dermoids.

We reviewed the clinical files of 10 patients who had undergone excision of unilateral epibulbar limbal dermoids. Preoperatively, all of the affected eyes had worse visual acuity (P less than .02) and more astigmatism (P less than .01) than the contralateral eyes. Postoperatively, every patient was cosmetically improved. Of the eight patients for whom both preoperative and postoperative visual acuity measurements had been obtained, in six it had changed minimally (less than or equal to 1 line), and in two it had improved (less than or equal to 2 lines). Surgical complications included persistent epithelial defects (40%) and peripheral corneal vascularization and opacity (70%). These complications do not outweigh the cosmetic and visual benefits of dermoid excision in selected patients.

Retinal arterial macroaneurysms: risk factors and natural history.

A case control study was conducted to identify the systemic and ocular risk factors for retinal arterial macroaneurysms. Forty-three patients with 52 photographically confirmed macroaneurysms were located. Forty-three age-matched, race-matched concurrent control patients were also identified. The patients with macroaneurysms had decreased visual acuity (p less than 0.0001) and a higher prevalence of hypertension (p = 0.037), female sex (p = 0.099), and retinal vein occlusions (p = 0.055) than controls. In patients with both a macroaneurysm and venous occlusion there was a 12.0 times higher prevalence of macroaneurysms in the area of retina drained by the occluded vein (p less than 0.05). Common findings associated with macroaneurysms included retinal haemorrhage (81% of patients), retinal exudate (70%), vitreous haemorrhage (30%), macular involvement (30%), and distal arteriolar narrowing (26%). Arteriolar occlusion occurred spontaneously (8%) or after laser photocoagulation (16%).

Murine tumor-induced platelet aggregation and coagulation: mechanisms, inhibitors, and species differences.

This study examined the platelet-aggregating and procoagulant activities of two hematogenously disseminating tumors, a mouse lymphoblastic leukemia (L5178Y) and a mouse renal adenocarcinoma (RAG). Tumor-induced human platelet aggregation was inhibited by addition of the following agents to platelet-rich plasma (PRP): a calcium channel blocker (verapamil), a chelator of divalent cations (EDTA), stimulators of adenylate cyclase (2-fluoroadenosine and forskolin), and inhibitors of cAMP phosphodiesterase (oxagrelate and papaverine). The platelet-aggregating activities of both cell lines were completely blocked by treatment of the cells with heat, sonication, phospholipase A2, and Triton X-100. These data suggest that L5178Y and RAG cell-induced human platelet aggregation are dependent on a heat-labile phospholipid component of the tumor cell membrane. L5178Y cells had greater platelet-aggregating activity in human plasma than in rat or mouse plasma, whereas RAG cells had greater procoagulant activity in rat or mouse plasma than in human plasma. The procoagulant activity of RAG cells in rat and mouse plasma was demonstrated by three lines of evidence: RAG cells induced heparinized PRP to clot; the thrombin inhibitor DAPA lengthened of the clotting time and the lag time before aggregation; and RAG cells shortened of the recalcification time of the plasma. The above data indicate that RAG cell-induced murine platelet aggregation and coagulation is dependent on thrombin generation.