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Biomedical subjects

C M G Cheung

Publications and source records attributed to C M G Cheung.

9 recordsLinked to original sources
PubMed2005

Anatomical success rate of macular hole surgery with autologous platelet without internal-limiting membrane peeling.

AIM: To describe our experience and success rate of macular hole surgery with pars plana vitrectomy with autologous platelet and without internal limiting membrane peel. METHODS: Retrospective review of 56 consecutive patients who underwent macular hole surgery. RESULTS: Anatomical success was achieved in 55 out of 56 patients (98.2%). Functional success was achieved in 37 out of 56 patients (66.1%). A total of 21 patients (37.5%) achieved postoperative visual acuity of 6/12 or better. No intraoperative complications were encountered. Postoperative complications included cataract progression in eight eyes and raised intraocular pressure in 20 eyes. CONCLUSIONS: Our success rate was comparable to that reported in macular hole surgery incorporating internal limiting membrane (ILM) peel or with autologous platelet without ILM peel.

Aged↗
PubMed2003

Inhibition of 11beta-hydroxysteroid dehydrogenase type 1 lowers intraocular pressure in patients with ocular hypertension.

BACKGROUND: Intraocular pressure (IOP) is maintained by a balance between aqueous humour (AH) production (dependent on sodium transport across a ciliary epithelial bi-layer) and drainage (predominantly through the trabecular meshwork). In peripheral epithelial tissues, sodium and water transport is regulated by corticosteroids and the 11beta-hydroxysteroid dehydrogenase (11beta-HSD) isozymes (11beta-HSD1 activating cortisol from cortisone, 11beta-HSD2 inactivating cortisol to cortisone). AIM: To analyse expression of 11beta-HSD in the human eye and investigate its putative role in AH formation. DESIGN: Multipart prospective study, including a randomized controlled clinical trial. METHODS: The expression of 11beta-HSD1 in normal human anterior segments was evaluated by in situ hybridization (ISH). RT-PCR for 11beta-HSDs, glucocorticoid and mineralocorticoid receptors (GR, MR) was performed on human ciliary body tissue. AH cortisol and cortisone concentrations were measured by radioimmunoassay on specimens taken from patients with primary open-angle glaucoma (POAG) and age-matched controls. Randomized, placebo-controlled studies of healthy volunteers and patients with ocular hypertension (OHT, raised IOP but no optic neuropathy) assessed the effect of oral carbenoxolone (CBX, an inhibitor of 11beta-HSD) on IOP. RESULTS: ISH defined expression of 11beta-HSD1 in the ciliary epithelium, while RT-PCR analysis of ciliary body tissue confirmed expression of 11beta-HSD1, with additional GR and MR, but not 11beta-HSD2 expression. In both POAG patients and controls, AH concentrations of cortisol exceeded those of cortisone. The CBX-treated healthy volunteers who demonstrated the largest change in urinary cortisol metabolites, indicative of 11beta-HSD1 inhibition, had the greatest fall in IOP. Patients with OHT showed an overall reduction of IOP by 10% following CBX administration, compared to baseline (p<0.0001). DISCUSSION: CBX lowers IOP in patients with ocular hypertension. Our data suggest that this is mediated through inhibition of 11beta-HSD1 in the ciliary epithelium. Selective and topical inhibitors of 11beta-HSD1 could provide a novel treatment for patients with glaucoma.

11-beta-Hydroxysteroid Dehydrogenase Type 2↗
PubMed2002

Peripapillary choroidal neovascularisation in sarcoidosis.

PURPOSE: To describe a rare manifestation of sarcoidosis. METHODS: Case report of a patient with histologically proven sarcoidosis, who developed peripapillary choroidal neovascularisation in the absence of uveitis or optic nerve disease. RESULTS: Oral corticosteroids achieved reduction in the size of the peripapillary choroidal neovascularisation. Laser treatment was effective in treating the remaining peripapillary choroidal neovascularisation, resulting in improvement of visual acuity. CONCLUSIONS: Isolated peripapillary choroidal neovascularisation is a previously unreported complication of sarcoidosis. A combination of oral corticosteroids and laser can be successful in treating this type of lesion, thereby preventing permanent visual loss.

Administration, Oral↗