PubMed Health⌕ Search

Biomedical subjects

Wai-Man Chan

Publications and source records attributed to Wai-Man Chan.

At least 19 recordsLinked to original sources
PubMed2006

Visual field and multifocal electroretinography and their correlations in patients on hydroxychloroquine therapy.

PURPOSE: To evaluate the effects of hydroxychloroquine on visual field and multifocal electroretinography (mfERG) and their correlations in patients taking hydroxychloroquine. METHODS: This was a cross-sectional study in which patients on hydroxychloroquine therapy underwent automated 10-2 threshold static visual field examination and mfERG recordings. Non-parametric unadjusted and age-adjusted Spearman correlation coefficients rho were calculated between the cumulative dose of hydroxychloroquine and the visual field mean deviation (MD) and pattern standard deviation (PSD) values; and the mfERG response amplitudes and peak latencies. Correlation analysis was also performed between the visual field MD and PSD values and the mfERG response amplitudes and peak latencies. RESULTS: A total of 26 eyes in 13 patients were analyzed. The mean duration of hydroxychloroquine therapy was 4.9 years and the mean cumulative dose was 574 g. No significant correlation was found between the cumulative dose of hydroxychloroquine and the visual field MD and PSD values. There were significant correlations between the cumulative dose of hydroxychloroquine and mfERG N1 and P1 response amplitudes for the central rings (ring 1-3). The correlations between the dose of hydroxychloroquine and mfERG N1 and P1 response amplitudes were strongest for the paracentral ring 2 (rho =-0.63 and rho =-0.62, respectively, P = 0.001). Significant correlations were also found between the visual field MD values and mfERG response amplitudes of various ring eccentricities. CONCLUSIONS: In patients on hydroxychloroquine, mfERG response amplitude correlated with both the 10-2 visual field MD values and with the cumulative dose of hydroxychloroquine used. The use of mfERG can provide objective measurement of retinal function in patients on hydroxychloroquine and may provide supplementary quantitative information to visual field findings.

Adult↗
PubMed2006

Aqueous humor levels of vascular endothelial growth factor and pigment epithelium-derived factor in polypoidal choroidal vasculopathy and choroidal neovascularization.

PURPOSE: To determine the aqueous levels of vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) in patients with active polypoidal choroidal vasculopathy (PCV) and choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) and pathologic myopia. DESIGN: Prospective, comparative control study. METHODS: Aqueous humors were collected from 32 eyes of 32 patients for either active PCV or CNV. Among them, 11 eyes had active and symptomatic PCV, 12 eyes had active CNV secondary to AMD, and nine eyes had active CNV of pathologic myopia. Levels of VEGF and PEDF were determined by commercially available enzyme-linked immunosorbent assay kits. A group of 10 aqueous samples from 10 patients who underwent cataract surgery without other ocular or systemic diseases comprised the controls. RESULTS: VEGF concentrations in aqueous humor were markedly increased in patients with PCV, CNV of AMD, and CNV of myopia when compared with the controls (analysis of variance [ANOVA], P < .001). VEGF levels in eyes with PCV were, however, significantly lower than those of exudative AMD (P = .045). The PEDF levels were also significantly different among the groups (ANOVA, P = .001), and we observed increased levels in PCV, CNV of AMD, and CNV of myopia. CONCLUSIONS: VEGF and PEDF factors were coexpressed and increased with positive correlation in aqueous humor of eyes with active PCV. The different levels of both factors in eyes of PCV and AMD might suggest distinct clinical entities or different angiogenesis courses between PCV and AMD.

Adult↗
PubMed2005

Homozygous HOXA1 mutations disrupt human brainstem, inner ear, cardiovascular and cognitive development.

We identified homozygous truncating mutations in HOXA1 in three genetically isolated human populations. The resulting phenotype includes horizontal gaze abnormalities, deafness, facial weakness, hypoventilation, vascular malformations of the internal carotid arteries and cardiac outflow tract, mental retardation and autism spectrum disorder. This is the first report to our knowledge of viable homozygous truncating mutations in any human HOX gene and of a mendelian disorder resulting from mutations in a human HOX gene critical for development of the central nervous system.

Autistic Disorder↗
PubMed2005

Failure of systemic antibiotic in preventing sequential endogenous endophthalmitis of a bronchiectasis patient.

PURPOSE: To report a rare presentation of bilateral, sequential Pseudomonas aeruginosa endogenous endophthalmitis in a woman with bronchiectasis. DESIGN: Interventional case report. METHODS: A 69-year-old woman with bronchiectasis developed right and then left endogenous endophthalmitis with the microbial of P. aeruginosa, even though a course of 3-week intravenous ceftazidime antibiotic was prescribed. RESULTS: The presentation of endogenous endophthalmitis in the right eye was late, and final visual acuity was hand movements. The condition was recognized much earlier in the left eye, and the infection was treated early on with vitrectomy and intravitreal antibiotics. Visual acuity at 1 year was stable at 20/40. CONCLUSION: Systemic antibiotic failed to eradicate the primary source of Pseudomonas infection in the bronchiectasis patient. Unusual, painful red eye may be the presenting feature of endogenous endophthalmitis. Early vitrectomy may be considered in endogenous endophthalmitis caused by virulent pathogens such P. aeruginosa.

Aged↗
PubMed2005

Intravitreal triamcinolone acetonide for choroidal granuloma in sarcoidosis.

PURPOSE: To report the clinical course of intravitreal triamcinolone acetonide on choroidal granuloma secondary to sarcoidosis that was refractory to systemic prednisolone DESIGN: Interventional case report. METHODS: A 29-year-old Chinese man with sarcoidosis presented with isolated posterior segment involvement in his left eye as retinal periphlebitis, retinal granulomas, and choroidal granuloma. Retinal periphlebitis and retinal granulomas responded well to oral corticosteroid but not the choroidal granuloma. It gradually grew in size and caused a drop in left-eye vision to 20/70. Intravitreal triamcinolone acetonide (4 mg) was injected three times in total. RESULTS: The choroidal mass began to shrink in size after the second injection and completely regressed after the third. The choroidal granuloma became a scar, with no angiographic leakage. The patient's visual acuity improved and remained stable at 20/40 at the last follow-up, 6 months after the last injection. CONCLUSIONS: Given the encouraging results, further study on intravitreal triamcinolone acetonide for macular and peripapillary choroidal granulomas secondary to systemic sarcoidosis is warranted.

Adult↗
PubMed2005

Multifocal electroretinographic changes in patients receiving hydroxychloroquine therapy.

PURPOSE: To evaluate the longitudinal changes in multifocal electroretinography (mfERG) in patients receiving hydroxychloroquine and to assess the effects of cumulative hydroxychloroquine dose on mfERG. DESIGN: Prospective cohort study. METHODS: Twenty-four eyes in 12 patients receiving hydroxychloroquine underwent mfERG recordings at baseline and 1 to 2 years later. The first negative (N1) and first positive (P1) response amplitudes and peak latencies were compared with normal controls. Serial changes in the pattern of mfERG abnormalities and in response amplitudes and peak latencies were also compared between eyes in which hydroxychloroquine therapy was continued or stopped. Correlation analyses were performed to assess the effects of a cumulative dose of hydroxychloroquine on mfERG. RESULTS: At baseline, reductions in N1 and P1 response amplitudes were observed in patients receiving hydroxychloroquine compared with controls. At follow-up, in addition to the reductions in N1 and P1 response amplitudes, increases in P1 peak latencies compared with controls were observed. In patients who stopped hydroxychloroquine therapy, there were significant increases in N1 and P1 response amplitudes at follow-up mfERG. CONCLUSIONS: Patients receiving hydroxychloroquine showed a longitudinal decline in retinal function; patients who stopped hydroxychloroquine therapy showed improvement. Although these data are insufficient to demonstrate the sensitivity of mfERG for evaluating early hydroxychloroquine toxicity, the results suggest that serial mfERG assessment may help detect early retinal changes associated with hydroxychloroquine therapy. Further studies with long-term results will be useful in clarifying the value of mfERG in evaluating early retinal toxicity due to hydroxychloroquine.

Adult↗