Reproducibility of corneal flap thickness in laser in situ keratomileusis using the Hansatome microkeratome.
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Biomedical subjects
Publications and source records attributed to D S Lam.
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PURPOSE: To evaluate the efficacy and safety of topical 2% lignocaine gel in providing analgesia during outpatient transpupillary or trans-scleral laser treatment of inflamed eyes. METHODS: A prospective study was carried out of consecutive eligible eyes undergoing laser treatment using 2% lignocaine gel as a topical anaesthetic and a coupling medium. At the conclusion of each procedure, patients were asked to grade a pain score (0 = no discomfort, 1 = mild discomfort, 2 = mild pain, 3 = moderate pain, 4 = severe pain). RESULTS: Twenty eyes in 19 patients received laser treatment. No pain was reported in 95% of cases treated (no discomfort in 75%, mild discomfort in 20%) and only mild pain in 5% (one patient). No adverse reactions were encountered in any of the patients. There were no complications associated with the procedures. CONCLUSIONS: Lignocaine 2% gel is safe and effective for outpatient transpupillary and trans-scleral laser treatment in inflamed eyes, providing adequate analgesia and serving as a coupling medium at the same time.
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PURPOSE: To investigate ocular complications arising from nephrotic syndrome and/or its treatments in children. METHODS: A cross-sectional study was conducted in a teaching hospital. A total of 31 paediatric patients with nephrotic syndrome were studied. Comprehensive ophthalmic assessments on best-corrected visual acuity, intraocular pressure, slit-lamp and fundus examination were taken. Information regarding histological diagnosis of nephrotic syndrome and its treatment regimen in each patient was reviewed and analysed. RESULTS: Bilateral posterior subcapsular cataracts were detected in three of 29 patients (10.3%) who received steroid therapy. Two had normal vision while one had visual acuity reduced to 6/15 in both eyes. The age of onset of the nephrotic syndrome in these three patients was 2 years, which was significantly younger than those without cataract (5.4 +/- 3.2 years, P < 0.001). Three patients (9.7%) had isolated asymptomatic fundal findings of tortuous and dilated retinal vessels. Hypertensive retinopathy was found in one patient (3.2%). No steroid-induced glaucoma, uveitis, ocular infection, or other eye complications related to the use of steroids or other immunosuppressive agents were noted. CONCLUSIONS: Children who have nephrotic syndrome often require prolonged, intermittent high dose of systemic corticosteroid therapy. Paediatricians should be aware of the potential risk of developing steroid-related complications, especially posterior subcapsular cataract. It appears to have a higher risk when steroid therapy is used in very young patients. Early detection would help to prevent amblyopia development, particularly in the group of immature eyes.
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PURPOSE: To study the efficacy and safety of diode laser peripheral iridoplasty as a first-line treatment of acute primary angle-closure glaucoma (PACG) without the use of systemic anti-glaucoma medications. PATIENTS AND METHODS: Nine consecutive patients with acute PACG were recruited into the study. Each patient received topical pilocarpine (4%), timolol (0.5%), apraclonidine (1%), and immediate diode laser peripheral iridoplasty as primary treatment. The intraocular pressures (IOPs) 15, 30, and 60 minutes after diode laser peripheral iridoplasty were documented by Goldmann applanation tonometry. RESULTS: The mean IOP of this group of patients was reduced from 66.3 +/- 9.7 mm Hg, before diode laser peripheral iridoplasty, to 36.6 +/- 16.4 mm Hg at 15 minutes, 26.3 +/- 12.6 mm Hg at 30 minutes, and 18.9 +/- 8.4 mm Hg at 60 minutes after diode laser peripheral iridoplasty. In seven of the nine patients, the corneal edema cleared up 1 hour after diode laser peripheral iridoplasty. In the remaining patient, the cornea cleared up 12 hours after diode laser peripheral iridoplasty. No significant complications were encountered. CONCLUSION: Diode laser peripheral iridoplasty, together with topical antiglaucoma medications without adjunctive systemic carbonic anhydrase inhibitors and hyperosmotic agents, appeared to be effective and safe in controlling the IOP in acute PACG.
PURPOSE: To report the efficacy and safety of combined phacoemulsification, intraocular lens implantation, and limited goniosynechialysis, followed by diode laser peripheral iridoplasty, in the treatment of cataract and chronic angle-closure glaucoma. METHODS: Patients with chronic angle-closure glaucoma with total synechial angle closure and intraocular pressures higher than 21 mm Hg on maximally tolerated medications, and concurrent cataract, underwent phacoemulsification with posterior chamber intraocular lens implantation and goniosynechialysis followed by diode laser peripheral iridoplasty to the inferior half of the angle. Intraoperative complications, postoperative visual acuity, intraocular pressures, and complications were evaluated. RESULTS: Seven eyes of seven patients received the operation, and the mean follow-up was 8.9 months (range, 2-16 months). The mean preoperative intraocular pressure was 33.0 +/- 4.8 mm Hg. The mean postoperative intraocular pressure at most recent follow-up was 13.3 +/- 2.9 mm Hg. The absolute success rate (intraocular pressure less than 21 mm Hg without medication) was 100%. The visual acuity of all eyes improved by more than two Snellen lines. Postoperative complications included intraocular pressure spike, hyphema, and transient corneal decompensation. CONCLUSION: It appears that phacoemulsification with intraocular lens implantation combined with inferior 180 degree goniosynechialysis followed by diode laser peripheral iridoplasty is an effective and safe surgical procedure for treating chronic angle-closure glaucoma with total synechial angle closure and cataract.
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AIM: To determine the pattern of rhodopsin mutations in Chinese retinitis pigmentosa (RP) patients. METHODS: The rhodopsin gene was examined in 101 RP patients and 190 controls from Hong Kong. RESULTS: Three coding changes were identified: Pro347Leu, Ala299Ser, and 5211delC. Each protein sequence alteration was found in one patient. Ala299Ser also existed in two controls. CONCLUSION: The C-terminal nonsense mutation may cause mis-sorting of rhodopsin protein. The finding of controls with Ala299Ser suggests this is only the third missense alteration reported that does not cause RP. The expected frequency of rhodopsin mutations in RP is <7% (2/101=2.0%, 95% confidence interval: 0.2%-7.0%).
High-throughput screening for single nucleotide polymorphisms (SNPs) or mutations can be achieved by inexpensive technologies. We modified the original protocols of conformation-sensitive gel electrophoresis (CSGE) to increase throughput several fold to 1.3 samples/min, which is about five times faster than denaturing high-performance liquid chromatography (DHPLC). The modifications include decreasing the gel thickness, increasing the number of lanes to 96, and increasing the number of samples per lane to seven. This high-throughput CSGE method is fast, robust, and as simple as the original protocols. Together with a two-stage strategy for screening homozygotes and the replacement of ethidium bromide with SYBR Gold DNA dye staining, this protocol is a reliable and cost-effective alternative for laboratories that require high-throughput screening.
OBJECTIVES: To determine the incidence of acute primary angle-closure glaucoma in the Hong Kong Chinese population, and to identify risk factors for this condition. DESIGN: Prospective study. SETTING: University teaching hospital, Hong Kong. PARTICIPANTS: Patients with acute primary angle-closure glaucoma presenting between 1 March 1998 and 29 February 2000. MAIN OUTCOME MEASURES: Demographic data, presenting symptoms and signs, temporal details of the presentation, and precipitating factors. The crude regional incidence was calculated according to the Hong Kong population census of 1991 and the age-specific incidence was calculated. RESULTS: Seventy-two cases (72 eyes of 72 patients) of acute primary angle-closure glaucoma were recruited. The crude incidence was 10.4 per 100,000 per year in the population aged 30 years and older. Patients at higher risk of attacks were those aged 70 years or older (age-specific incidence, 58.7 per 100,000 per year) and females, who had a relative risk of 3.8 compared with males (95% confidence interval, 1.7-8.4). Only four (5.6%) patients had a positive family history of acute primary angle-closure glaucoma. Seventeen (23.6%) patients were noted to have an upper respiratory tract infection before the attack, and 25 (34.7%) patients had taken antitussive agents. There was a statistically significant inverse correlation between the monthly attack rate and the monthly rate of influenza (Spearman's rank correlation coefficient = -0.388; P=0.031). CONCLUSION: There is a high incidence of acute primary angle-closure glaucoma among Chinese residents of Hong Kong, with elderly females at highest risk. A significant proportion of patients reported upper respiratory tract infection or the use of antitussive medication prior to attacks.