Biomedical subjects

Tamer H Mahmoud

Publications and source records attributed to Tamer H Mahmoud.

3 recordsLinked to original sources

PubMed2007

Natural history of foveolar lucencies observed by optical coherence tomography after macular hole surgery.

PURPOSE: To describe the incidence, course, and anatomic and functional outcomes of foveolar lucencies observed by optical coherence tomography after macular hole surgery. METHODS: Retrospective chart review of all idiopathic macular hole surgeries performed between February 2002 and August 2003. Available data involving eyes with foveolar lucencies after macular hole surgery were collected regarding best-corrected visual acuity, lens status, slit-lamp biomicroscopy, and optical coherence tomography before and at follow-up visits ranging from 1 week to 27 months after macular hole surgery. RESULTS: Thirty-five eyes of 35 patients were identified. Foveolar lucencies were detected by optical coherence tomography in 9 of the 35 eyes (26%). Operative procedures included creation of a posterior vitreous detachment in 8 eyes and indocyanine green-assisted internal limiting membrane peeling in 5 eyes. Intraocular tamponade consisted of 30% sulfur hexafluoride gas in 6 eyes and 20% perfluoropropane gas in 3 eyes with at least 1 week of face-down positioning. Postoperative visual acuity showed gradual improvement coinciding with decreasing size and eventual disappearance (3 to 11 months) of the foveolar lucency. CONCLUSION: Foveolar lucencies observed by optical coherence tomography are a common finding after macular hole surgery (26%). They occur with and without indocyanine green-assisted internal limiting membrane peeling. Earlier disappearance of the foveolar lucency does not correlate with the type of gas used for tamponade. They gradually decrease and eventually resolve with time without additional surgical intervention and with further improvement of visual acuity.

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PubMed2003

Lensectomy and vitrectomy decrease the rate of photoreceptor loss in rhodopsin P347L transgenic pigs.

BACKGROUND: Photoreceptor degeneration in retinitis pigmentosa (RP) runs an inevitable, gradually progressive course. A wide variety of growth factors of different origins have been shown to slow the rate of degeneration in some rodent models of RP. Recently, lens-derived neurotrophic factors have been shown to rescue degenerating ganglion cells in crush models of the optic nerve. Our objective was to evaluate the potential rescue effect of lensectomy and vitrectomy (L&V) on photoreceptor degeneration in a large-animal model, the rhodopsin P347L transgenic pig. METHODS: We operated on one eye of each of 49 3-week-old pigs--15 vitrectomies and 34 L&V, 6 of which received steroids. Retinal paraffin sections were prepared for all eyes, in addition to immunohistochemistry in four eyes, 8 weeks after L&V. RESULTS: At eight weeks after L&V, operated eyes showed significantly more nuclei in the outer nuclear layer (ONL) than the unoperated fellow eyes. The better preservation of the ONL persisted but was less prominent by 20 weeks after surgery. Steroid treatment did not markedly reduce the better preservation of the ONL seen at 8, 10, and 12 weeks after surgery. The significant difference in cell count between operated and unoperated eyes in the L&V group at 8 weeks was due to the difference in the number of rods, not the cones. CONCLUSION: Lensectomy and vitrectomy delay photoreceptor degeneration in rhodopsin P347L transgenic pigs. Lens-related rescue effect is a probable reason for the delayed degeneration.

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PubMed2002

Intraoperative choroidal hemorrhage in the Osler-Rendu-Weber syndrome.

PURPOSE: To describe a patient with Osler-Rendu-Weber syndrome who developed a nonsimultaneous intraoperative choroidal hemorrhage in each eye. METHOD: Interventional case report. A 65-year-old Caucasian woman with Osler-Rendu-Weber syndrome developed a choroidal hemorrhage in the left eye during vitrectomy for a complicated retinal detachment with a poor visual outcome. Fifteen years later, she developed a macula on retinal detachment in the right eye, which also had a dense cataract. Immediately after uncomplicated phacoemulsification and intraocular lens implantation, under monitored anesthesia care and retrobulbar block, and without valsalva stress, ophthalmoscopy demonstrated a choroidal hemorrhage. A planned scleral buckle was replaced by pneumatic retinopexy. RESULTS: Seven months postoperatively, the retina remained attached with resolution of the choroidal hemorrhage. Visual acuity was 20/30. CONCLUSION: Choroidal hemorrhage may occur more commonly in individuals with Osler-Rendu-Weber syndrome. Recognition of this possible association and institution of appropriate intraoperative precautions may facilitate a good visual outcome.

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