Victoria W. Y. Wong

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.

Quality of Reporting of Key Methodological Items of Randomized Controlled Trials in Clinical Ophthalmic Journals

Purpose: To evaluate the reporting quality of key methodological items in randomized controlled trials (RCTs) in four general clinical ophthalmology journals.Methods: The reporting of 11 key methodological items in RCTs published in American Journal of Ophthalmology, Archives of Ophthalmology, British Journal of Ophthalmology and Ophthalmology in the year 2005 was assessed. Results : Sixty-seven eligible RCTs were assessed and the mean number of items reported was 6.3 per RCT. No significant difference in the mean number of items reported was found between the four journals (P = 0.20). The most frequently reported item was ethics approval and informed consent (97.0%), followed by masking status (85.1%), description of withdrawals (76.1%), adverse events (73.1%), and intention-to-treat analysis (71.6%). Details on sequence generation, randomization restriction, allocation concealment, allocation implementation, patient flow diagrams, and sample size calculation were reported in < 50% of the RCTs assessed. Both sample size and page length of the RCTs correlated with the number of methodological items reported (P = 0.024 and P = 0.008, respectively). Conclusions: Similar to other specialties, rooms for improvement exist in the reporting of key methodological items of RCTs in clinical ophthalmic journals. Stricter adoption of the CONSORT statement might enhance the reporting quality of RCTs in ophthalmic journals.

One-year outcomes of conventional and accelerated collagen crosslinking in progressive keratoconus

We compared one-year outcomes of conventional (3 mW/cm2, 365-nm ultraviolet-A light, 30 minutes) and accelerated (18 mW/cm2, 365-nm ultraviolet-A light, 5 minutes) collagen crosslinking (CXL) in patients with progressive keratoconus. Main outcome measures were change in keratometry, uncorrected visual acuity (UCVA), and best-corrected visual acuity (BCVA). Nineteen patients in each group completed 1-year follow-up. Preoperatively, there were no inter-group differences for age, keratometry, corneal thickness, and spherical equivalent (p > 0.127). One year postoperatively, maximum and minimum keratometry were flattened by 1.6 diopters (p < 0.023) and 2 diopters (p < 0.047) respectively after conventional CXL, and, 0.47 diopters (p = 0.471) and 0.19 diopters (p = 0.120) respectively after accelerated CXL. Association analysis showed significant negative association between baseline maximum keratometry and change in maximum keratometry after accelerated CXL (p = 0.002) but not after conventional CXL (p = 0.110). Corneal thickness was reduced significantly in both groups (p = 0.017). An improvement in UCVA (p < 0.001) and BCVA (p < 0.022) was noted in both groups along with a reduction in spherical equivalent postoperatively (p < 0.026). There were no inter-group differences for any of the parameters postoperatively (p > 0.184). Although no statistically significant differences were observed between both treatment modalities, a more effective topographic flattening was observed with conventional CXL as compared to accelerated CXL in this study.

Diamond burr polishing for recurrent corneal erosions: results from a prospective randomized controlled trial.

Purpose: To evaluate the use of diamond burr polishing as an in-office treatment for recurrent corneal erosion (RCE). Methods: A double-masked randomized controlled trial was conducted. Patients with RCE secondary to trauma or anterior basement membrane dystrophy underwent epithelial debridement (ED) or diamond burr superficial keratectomy (DBSK) at the slit lamp. Patients were followed up for 6 months, and the recurrence rates of RCE and visual outcomes were compared. Results: Forty-eight eyes of 48 patients were recruited. The mean ± SD age was 38.3 ± 12.9 years. Twenty-five patients underwent DBSK, and 23 patients received ED alone. There was no significant difference in the baseline demographics between the 2 groups. Kaplan-Meier survival analysis showed significantly less major and minor recurrences and less need for repeated surgical interventions in the DBSK group compared with the ED group (P < 0.001). Eyes in the DBSK group also had significantly lower mean magnitude of astigmatism after treatment compared to the ED group (P = 0.021). Conclusion: Diamond burr polishing is a safe, convenient, and inexpensive treatment option for the management of RCE and resulted in better outcomes compared to simple epithelial debridement.

Pediatric ocular surface infections: a 5-year review of demographics, clinical features, risk factors, microbiological results, and treatment.

Purpose: To evaluate the clinical and microbiological profiles of pediatric patients with ocular surface infections requiring corneal or conjunctival scraping for diagnosis. Methods: The medical records of 138 consecutive patients aged 18 years or younger who had undergone corneal or conjunctival scraping over a 5-year-period in a tertiary ophthalmic center were reviewed. Demographics, clinical features, risk factors, microbiological results, and treatment were recorded. Results: Ocular surface infections were classified into 4 groups: infectious keratitis (group 1); blepharokeratoconjunctivitis (group 2); conjunctivitis (group 3); and congenital nasolacrimal duct obstruction or dacryocystitis (group 4). The groups had different mean ages of presentation, with group 4 presenting the youngest at 2 years and group 1 presenting the oldest at 14 years. Contact lens wear and blepharitis were the major risk factors. The positive culture rate was 60.9%, of which 65.5% were Gram-positive organisms. Coagulase-negative staphylococci were the most common organisms (23.2%), followed by Pseudomonas aeruginosa (9.4%) and Staphylococcus aureus (8.0%). Microbial yield was highest in group 1 (86%) and lowest in group 3 (38.6%). There were 9 orthokeratology-related infectious keratitis cases (18%) and 9 chlamydial ophthalmia neonatorum cases isolated. Conclusions: With increasing contact lens wear in the pediatric and adolescent populations and the common occurrence of blepharokeratoconjunctivitis and staphylococcal ocular surface infections, parents and children should be highly vigilant with eyelid hygiene and contact lens practice.

Comparison of lidocaine 2% gel versus amethocaine as the sole anesthetic agent for strabismus surgery

PURPOSE To compare the efficacy of lidocaine 2% gel with amethocaine 1% eyedrops as the sole anesthetic agent for one-stage adjustable suture strabismus surgery. DESIGN Prospective, double-masked randomized trial. PARTICIPANTS Fourteen consecutive patients scheduled to undergo bilateral and symmetrical strabismus surgery under topical anesthesia in one institution. METHODS Each patient was randomized to receive lidocaine 2% gel in one eye and amethocaine 1% eyedrops in the other eye as the sole anesthetic agent for surgery. Masking of the patient and surgeon was ensured by administration of a placebo gel and eyedrop as part of the regimen. Pain and discomfort were assessed via a 10-cm visual analog scale. MAIN OUTCOME MEASURES Subjective pain and discomfort perceived during surgery were assessed separately by the patient and the surgeon, and the need for any additional anesthesia was recorded. RESULTS A total of 14 subjects indicated mean pain and discomfort scores of 2.6 and 3.2 respectively, for lidocaine gel, and 5.3 and 6.2, respectively, for amethocaine drops (P = 0.01). The mean number of additional drops required by eyes randomized to lidocaine gel was 0.3, compared with 1.6 for amethocaine drops (P = 0.02). CONCLUSIONS In terms of pain control, lidocaine 2% gel alone is a superior topical anesthetic for one-stage adjustable suture strabismus surgery when compared with amethocaine 1% eyedrops.

Orthokeratology-Associated Infectious Keratitis in a Tertiary Care Eye Hospital in Hong Kong

PURPOSE To analyze cases of orthokeratology-associated infectious keratitis managed in a tertiary care eye hospital in Hong Kong between 2003 and 2013. DESIGN Retrospective study. METHODS Case records of patients with infectious keratitis attributable to orthokeratology contact lenses were analyzed. Data analyzed included clinical features, microbiological evaluation, and treatment outcomes. RESULTS A total of 23 patients were included (16 female, 7 male, mean age: 15.0 ± 4.2 years; range: 9-23 years). All patients were using overnight orthokeratology for an average of 2.7 ± 2.8 years (range: 3 months - 10 years) before the onset of infection. Clinical features included corneal infiltrate (n = 14, 60.9%) and corneal perineuritis (n = 12, 52.2%). Fifteen eyes (65.2%) had a positive microbiological culture obtained from corneal scrapings. The most commonly isolated organism was Pseudomonas aeruginosa (n = 6), followed by coagulase-negative Staphylococcus (n = 5) and Acanthamoeba (n = 3). Five cases of Pseudomonas aeruginosa and 5 cases of Acanthamoeba were identified from contact lenses or contact lens solution. The mean duration from disease onset to remission was 31.9 ± 34.9 days (range: 6-131 days). All patients responded to medical treatment, and no emergency surgical intervention was needed. The best-corrected logMAR visual acuity improved significantly from 0.62 ± 0.51 (20/83 Snellen) to 0.15 ± 0.20 (20/28 Snellen) (Wilcoxon signed rank test, P < .001). CONCLUSIONS Orthokeratology-associated infectious keratitis continues to be a serious problem, especially in regions with high prevalence of myopia. Early clinical and microbiological diagnosis and intensive treatment can improve final visual outcomes.

Different Topographic Response Between Mild to Moderate and Advanced Keratoconus After Accelerated Collagen Cross-linking.

Purpose: To evaluate the clinical and topographic effects after accelerated corneal collagen cross-linking (CXL) in keratoconus. Methods: This was a prospective interventional study in 25 eyes of 24 Asian patients with keratoconus, where 10 eyes in group 1 had mild to moderate keratoconus with the steepest keratometry reading (Kmax) < 58 diopters (D), and 15 eyes in group 2 had advanced keratoconus with Kmax ≥ 58.0 D. The patients underwent accelerated CXL with 18 W/cm2 UV-A light for 5 minutes. Clinical and topographic parameters were obtained before and 1 year after treatment. Results: Overall, spectacle-corrected distance visual acuity, refraction, average keratometry readings, Kmax, anterior elevation at the apex, and corneal endothelial cell density remained stable (P < 0.102). Posterior elevation at the apex increased at 1 year (P = 0.002). The thinnest pachymetry readings also showed significant reduction (P < 0.001). Kmax in group 1 increased by 1.00 ± 1.63 D (range, −2.2 to 5.4 D; P = 0.012), whereas Kmax in group 2 reduced by 1.69 ± 2.61 D (range, −8.4 to 3.2 D; P = 0.013) at 1 year after accelerated CXL. The change in Kmax between the 2 groups was significantly different (P < 0.001). There was no intergroup difference for the change in other parameters. A significant correlation was found between the preoperative Kmax and postoperative change in Kmax at 1 year (r = −0.648; P < 0.001). Conclusions: Accelerated CXL seems to be effective in preventing progression and causing topographic flattening in advanced cases of keratoconus but not as effective in the less progressed counterparts.

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

AimTo compare the safety and effectiveness of trypan blue capsule staining under air vsunder viscoelastic.MethodsA 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.ResultsPhacoemulsification 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.ConclusionsTrypan 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.

Long-term results of oral valganciclovir for treatment of anterior segment inflammation secondary to cytomegalovirus infection

Background The purpose of this study was to assess the efficacy of oral valganciclovir in the treatment of anterior segment inflammation caused by cytomegalovirus (CMV) infection. Methods Consecutive patients with anterior segment inflammation due to CMV causing anterior uveitis or corneal endotheliitis treated with oral valganciclovir were reviewed. Diagnosis of CMV infection was confirmed by polymerase chain reaction of the aqueous aspirate prior to commencement of oral valganciclovir. All patients were treated with an oral loading dose of 900 mg valganciclovir twice daily for at least 2 weeks, followed by an additional 450 mg valganciclovir twice-daily maintenance therapy. Changes in visual acuity, intraocular pressure (IOP), use of antiglaucomatous eye drops, and recurrence were analyzed. Results Thirteen eyes of 11 patients were followed for a mean of 17.2 months. Two patients had bilateral corneal endotheliitis. All eyes had absence of anterior segment inflammation within 3 weeks after treatment. Following treatment, the mean logMAR visual acuity improved significantly from 0.58 at baseline to 0.37 at the last follow-up (P = 0.048). The mean IOP and number of antiglaucomatous eye drops also decreased significantly (P = 0.021 and P = 0.004, respectively). Five (38.5%) eyes had recurrence of anterior uveitis after valganciclovir was stopped and required retreatment with oral valganciclovir. Conclusion Oral valganciclovir appeared to be effective in controlling CMV anterior uveitis, resulting in visual improvement and IOP reduction following control of inflammation. However, despite the initial clinical response in all cases, recurrence after cessation of oral valganciclovir could occur.