Joseph A. Khawly

Intraocular lens changes after short- and long-term exposure to intraocular silicone oil: An in vivo study

OBJECTIVE Silicone oil frequently is used as a vitreous substitute after complex vitreoretinal procedures. The authors sought to study the effect of short- and long-term exposure to silicone oil on polymethyl methacrylate (PMMA, MC60BM; Alcon, Ft. Worth, TX), silicone (SI-30NB; AMO, Irvine, CA), and soft acrylic (MA60BM; Alcon) intraocular lenses (IOLs). DESIGN An experimental animal study. INTERVENTION Forty-one New Zealand white rabbits underwent lensectomy, vitrectomy, capsulotomy, and placement of one of the three types of IOLs into the ciliary sulcus. All lenses were weighed before implantation and 24 hours after explanation. In the short-term study, an fluid-air exchange was performed followed by the use of silicone oil (1000 centistokes) to coat the posterior lens surface. Immediately thereafter, an air-fluid exchange was performed and the remaining silicone on the posterior lens surface was aspirated or wiped or both for 1 minute using a soft-tipped extrusion cannula for 1 minute. In the long-term study, the posterior segment was filled with 1000 centistokes silicone oil after fluid-air exchange. Animals were observed by slit-lamp biomicroscopy and photographed at 1 week, 1 month, and 3 months after surgery. At 3 months, all animals underwent silicone-fluid exchange, an attempt to manually remove any remaining silicone oil, and lens explanation. RESULTS In the short-term study, no silicone oil remained after manual wiping and/or aspiration in any of the four rabbits implanted with PMMA or acrylic IOLs. In the animals with silicone IOLs, a significant amount of silicone oil remained on the posterior lens surface of all lenses (P < 0.01 for silicone vs. acrylic and silicone vs. PMMA). No statistically significant difference was found when comparing the lens weights in each group before and after implantation. In the long-term study, aqueous droplet formation was found on the posterior lens surface of six of nine PMMA IOLs and ten of ten silicone IOLs at 3 months. No opacities were observed in the group with acrylic IOLs (P < 0.001 for acrylic vs. silicone, P = 0.0018 for acrylic vs. PMMA, and P = 0.047 for PMMA vs. silicone). Adherent silicone oil remained on two of nine PMMA IOLs and on none of ten acrylic IOLs. In contrast, a significant amount of silicone oil remained on the posterior lens surface of ten of ten silicone IOLs (P < 0.001 for silicone vs. acrylic and silicone vs. PMMA). Furthermore, there was a statistically significant increase in lens weights before and after implantation in the silicone IOL group but not in the PMMA or acrylic group (P < 0.01). CONCLUSIONS It is extremely difficult or impossible to remove remaining silicone oil from the posterior surface of a silicone IOL after short- or long-term exposure to silicone oil. This oil may interfere with the surgeons view of the retina and may diminish the patients visual acuity. In contrast, oil is readily removed from the posterior surface of an acrylic IOL. The authors therefore recommend the use of a soft acrylic or PMMA IOL over a silicone IOL when choosing a lens for implantation in patients who may require vitreoretinal procedures with silicone oil tamponade.

Choroidal Hemorrhage Associated With Systemic Tissue Plasminogen Activator

PURPOSE To determine the cause of spontaneous choroidal hemorrhage in a 67-year-old man after a myocardial infarction and administration of tissue plasminogen activator. METHODS The patient underwent ocular examination. RESULTS The patient retained excellent visual acuity and the choroidal hemorrhage resolved completely within two months. CONCLUSION The administration of tissue plasminogen activator was responsible for the large extent of hemorrhage and should be considered in the differential diagnosis of hemorrhagic choroidal detachment.

Appearance and rapid growth of retinal tumor (reactive astrocytic hyperplasia

Abstract · Background: Tumors of the retina are often seen in association with systemic syndromes such as neurofibromatosis, tuberous sclerosis, and von Hippel-Lindau disease. These masses are either astrocytic hamartomas or capillary hemangiomas. Retinal tumors unassociated with other systemic disease have also been reported. · Methods: The ophthalmologic evaluation and clinical course of a 65-year-old woman who developed an epiretinal membrane followed by a vascularized retinal mass in the macular area are described. · Results: Appearance and rapid growth of the lesion were documented with fundus photography and fluorescein angiography. The lesion was treated with photocoagulation following growth that threatened the foveal region. Choroidal neovascularization subsequently developed toward the fovea, and visual acuity has remained poor. After 4 years of follow-up no local recurrence or systemic disease possibly related to the tumor has occurred. · Conclusions: This is the first report of documented appearance and rapid growth of a retinal tumor that resembles a reactive astrocytic hyperplasia.

Retinopathy and Optic Neuropathy in Bone Marrow Transplantation for Breast Cancer

PURPOSE To characterize the ocular toxicity of a bone marrow transplant regimen does not include total body or focal head irradiation. METHODS Nine patients with advanced breast cancer were referred for visual symptoms after high-dose chemotherapy with cisplatin, cyclophosphamide, and carmustine and autologous bone marrow transplantation without total body irradiation or local head irradiation. RESULTS Symptoms consistent with optic neuropathy and retinopathy developed in five patients. Retinopathy alone developed in three patients and optic neuropathy alone developed in one. Retinal abnormalities included cotton-wool spots, intraretinal hemorrhages, and macular exudate. Optic nerve findings included disk swelling and subsequent pallor. Symptoms and signs associated with retinopathy were generally reversible, whereas those associated with optic neuropathy often were permanent. Retinopathy and/or optic neuropathy developed in all of the patients from 1 to 5 months after bone marrow transplantation. Resolution or stabilization of findings was observed 2-4 months after presentation. Two patients with optic neuropathy showed progression of field and acuity loss after 4 months. When compared with control subjects, the exposure of patients to cyclophosphamide and carmustine was no different. However, cisplatin exposure was 1.2-fold higher in patients with ocular toxicity compared with control subjects. CONCLUSION Optic neuropathy and retinopathy are presumed to arise from the administration of a high-dose chemotherapy regimen. As techniques in supportive care improve, long-term adverse effects of these therapies now are becoming apparent.