Hand hygiene and risk of influenza virus infections in the community: a systematic review and meta-analysis.

Community-based prevention strategies for seasonal and pandemic influenza are essential to minimize their potential threat to public health. Our aim was to evaluate the efficacy of hand hygiene interventions in reducing influenza transmission in the community and to investigate the possible modifying effects of latitude, temperature and humidity on hand hygiene efficacy. We identified 979 articles in the initial search and 10 randomized controlled trials met our inclusion criteria. The combination of hand hygiene with facemasks was found to have statistically significant efficacy against laboratory-confirmed influenza while hand hygiene alone did not. Our meta-regression model did not identify statistically significant effects of latitude, temperature or humidity on the efficacy of hand hygiene. Our findings highlight the potential importance of interventions that protect against multiple modes of influenza transmission, and the modest efficacy of hand hygiene suggests that additional measures besides hand hygiene may also be important to control influenza.

Perilimbal conjunctival pigmentation in Chinese patients with vernal keratoconjunctivitis.

PURPOSE: To document the disease spectrum and evaluate the presence of perilimbal conjunctival pigmentation in Chinese patients with vernal keratoconjunctivitis (VKC). METHOD: A case-control study was conducted between November 2004 and July 2005. Patients aged 18 or younger with VKC and age-matched children attending our eye clinic for refractive or orthoptic problems were recruited and compared. Detailed slit-lamp examination was performed noting in particular the presence of perilimbal conjunctival pigmentation, the severity of papillary reaction, and corneal complications of VKC. RESULTS: A total of 19 patients and 23 controls were evaluated. The presence of bilateral large tarsal or limbal papillae and epithelial defect were significantly associated with symptoms severity (Fisher's exact test, P=0.015 and P=0.035 respectively). All VKC patients were found to have perilimbal conjunctival pigmentation in at least one eye. There was a significant correlation in the colour and density of pigments between the two eyes (Sperman's rho=0.93, P<0.001). None of the controls was found to have such perilimbal conjunctival pigmentation (Fisher's exact test, P<0.001). CONCLUSION: The presence of perilimbal conjunctival pigmentation appears to be a consistent clinical finding in Chinese patients with VKC and may be a useful diagnostic sign for patients with subtle signs or symptoms.

A prospective study on trypan blue capsule staining under air vs under viscoelastic.

AIM: To compare the safety and effectiveness of trypan blue capsule staining under air vs under viscoelastic. METHODS: A total of 52 consecutive patients planned for phacoemulsification of white mature cataract were randomly assigned to trypan blue staining under air or under viscoelastic. Perioperative changes in best-corrected visual acuity (BCVA), central corneal thickness (CCT), and endothelial cell density (ECD) were compared between the two groups. The differences in operating and phacoemulsification times, staining pattern, and complications between the two groups were also recorded. RESULTS: Phacoemulsification of white mature cataract was performed in 50 (96%) eyes. The median preoperative BCVA was hand movement. No significant differences in the baseline characteristics were found between the two groups. At 3 months after phacoemulsification, the median BCVA improved to 0.8. The mean CCT returned to preoperative level by 1 month postoperatively and the mean ECD loss was 11.9% 3 months postoperatively. No significant differences in median BCVA, mean phacoemulsification and operation times, mean CCT, and mean ECD were found between the two groups. CONCLUSIONS: Trypan blue staining of the anterior lens capsule under air or under viscoelastic were similarly effective and safe methods for the phacoemulsification of white mature cataract.

Idiopathic macular hole surgery in Chinese patients: a randomised study to compare indocyanine green-assisted internal limiting membrane peeling with no internal limiting membrane peeling.

OBJECTIVE: To compare the anatomical and visual outcomes of primary idiopathic macular hole surgery using indocyanine green-assisted internal limiting membrane peeling versus no internal limiting membrane peeling. DESIGN: Prospective randomised controlled clinical trial. SETTING: University teaching hospital, Hong Kong. PATIENTS: Fifty-one eyes of 49 Chinese patients with primary idiopathic macular hole were studied. INTERVENTIONS: Patients were randomised to undergo pars plana vitrectomy with indocyanine green-assisted internal limiting membrane peeling (26 eyes) or surgery without internal limiting membrane peeling (25 eyes). Perfluorocarbon gas was used in all cases as internal tamponade. MAIN OUTCOME MEASURES: Primary macular hole closure rate and best-corrected visual acuity. RESULTS: The mean follow-up duration was 12 months (range, 6-23 months). Respectively to the indocyanine green-assisted internal limiting membrane peeling group and non-internal limiting membrane peeling group, the primary anatomical closure rate was 92.3% and 32.0% (P<0.001), whereas improvement in best-corrected visual acuity was 3.7 and 1.5 lines (P=0.002). More eyes in the first group (84.6%) had improvement of 2 or more lines of best-corrected visual acuity after surgery than in the second group (32.0%) [P<0.001]. Multivariate logistic regression showed indocyanine green-assisted internal limiting membrane peeling was the only significant predictor for primary closure of the macular hole (adjusted odds ratio=30.8). CONCLUSION: Indocyanine green-assisted internal limiting membrane peeling in idiopathic macular hole surgery results in significantly better anatomical and visual outcomes compared with non-internal limiting membrane peeling in Chinese patients.

Trypan blue- and indocyanine green-assisted epiretinal membrane surgery: clinical and histopathological studies.

PURPOSE: To evaluate the clinical outcome and electron microscopic findings of trypan blue (Tb) and indocyanine green (ICG) assisted epiretinal membrane (ERM) surgery. METHODS: This is a prospective consecutive noncomparative interventional case series. After pars plana vitrectomy, 0.1 ml of 0.6 mg/ml Tb solution was applied for 1 min under air for ERM staining. After ERM removal, internal limiting membrane (ILM) was further peeled after staining with 0.2 ml of 1 mg/ml ICG solution. Intraoperative specimens were sent for electron microscopy. Tb was considered useful if the edge of ERM was stained where peeling could be initiated with a clearer visualisation of the overall extent of the ERM. RESULTS: In all, 16 eyes from 16 patients were recruited. There were nine grade 1 ERMs, five grade 2 ERMs, and two grade 3 ERMs. Tb was useful in six (67%) of the nine eyes with grade 1 ERMs and in all eyes with grade 2 or 3 ERMs. The three remaining grade 1 ERMs were removed together with surrounding ILM that was stained by ICG. The mean line of improvement was 1.3 lines with the median BCVA improved from 6/12 to 6/9. All 16 eyes had symptomatic improvement and none developed ERM recurrence. No complication related to Tb or ICG was observed clinically or angiographically. Electron microscopy of the Tb-stained ERM specimens showed fragments of ILM in all specimens. CONCLUSIONS: Tb and ICG are useful intraoperatively to improve the visualisation and facilitate complete removal of ERM and ILM in macular ERM surgery.

Is ophthalmology evidence based? A clinical audit of the emergency unit of a regional eye hospital.

AIM: To evaluate the proportion of interventions that are evidence based in the acute care unit of a regional eye hospital. METHODS: A prospective clinical audit was carried out at Hong Kong Eye Hospital in July 2002 to investigate the extent to which ophthalmic practices were evidence based. The major diagnosis and intervention provided were identified through chart review. A corresponding literature search using Medline and the Cochrane Library was performed to assess the degree to which each intervention was based on current, best evidence. Each diagnosis intervention pair was accordingly analysed and graded. The level of best, current evidence supporting each intervention was graded and analysed. RESULTS: A total of 274 consecutive consultation episodes were examined. 22 cases were excluded since no diagnosis or intervention was made during the consultation. 108 (42.9%) patient interventions were found to be based on evidence from systematic reviews, meta-analyses, or randomised controlled trials (RCT). Evidence from prospective or retrospective observational studies supported the interventions in 86 (34.1%) patients. In 58 (23.0%) cases, no evidence or opposing evidence was found regarding the intervention. The proportion of evidence based on RCT or systematic reviews was higher for surgical interventions compared with non-surgical interventions (p=0.007). The proportion of interventions based on RCT or systematic reviews was higher for specialist ophthalmologists than trainee ophthalmologists (p=0.021). CONCLUSION: This study demonstrated that the majority of interventions in the ophthalmic unit were evidence based and comparable to the experience of other specialties.

Changing patterns of strabismus: a decade of experience in Hong Kong.

BACKGROUND/AIMS: Racial variation in the pattern of strabismus is known, but few large scale studies on non-white populations are available. Furthermore, longitudinal change in this pattern within a local setting has not been well documented in the past. This study aims to support the clinical impression that exotropia is more common in Chinese patients, and that the proportion of patients with exotropia has been increasing in the past decade. METHODS: A total of 2704 consecutive patients with the diagnosis of primary horizontal strabismus, seen in the strabismus clinic of the Hong Kong Eye Hospital, were retrospectively analysed to determine the relative prevalence of esotropia and exotropia. Characteristics recorded include patient demographics, type of strabismus, and whether the nature of the squint was constant or intermittent. RESULTS: 742 (27.4%) patients were found to have esotropia, 548 (20.3%) had constant exotropia, 1213 (44.9%) had intermittent exotropia, and 201 (7.4%) had microtropia. The proportion of exotropic to esotropic patients was shown to increase steadily throughout the past decade (p<0.0001). This was mainly accounted for by an increase in the number of patients with intermittent exotropia, and a corresponding decrease in the number of patients with esotropia. CONCLUSION: Exotropia was shown to be more prevalent than esotropia in a Hong Kong Chinese population. Furthermore, the proportion of patients with intermittent exotropia appears to be increasing, in contrast with esotropic patients. The exact nature of this trend, and possible aetiological factors will require further study.