James Muecke

Complications of mitomycin C therapy in 100 eyes with ocular surface neoplasia

Aim: To determine the complications associated with mitomycin C (MMC) in the treatment of ocular surface neoplasia. Methods: A retrospective and consecutive study of 100 eyes in 91 patients with ocular surface neoplasia treated with MMC in a single centre between November 1998 and January 2005. Outcome measures included complications of MMC and the treatment required for these complications. Results: One to three 7 day cycles of topical MMC 0.04% four times a day were given to 59 eyes with localised corneal-conjunctival intraepithelial neoplasia (CIN), 19 eyes with diffuse CIN, six eyes with recurrent CIN, one eye with ocular surface squamous cell carcinoma, three eyes with primary acquired melanosis (PAM) with atypia, nine eyes with conjunctival malignant melanoma (MM), two eyes with sebaceous carcinoma with pagetoid spread, and one eye with recurrent atypical fibroxanthoma. Nine patients had bilateral CIN. 31 (34%) cases developed an allergic reaction to MMC and 14 (14%) eyes had epiphora secondary to punctal stenosis at a mean follow up period of 26.5 months. Conclusion: In the largest study looking at complications of topical MMC in the treatment of ocular surface neoplasia, allergic reaction and punctal stenosis are relatively common. Serious complications were not observed suggesting the safe use of MMC in mid-term follow up.

Prevalence of glaucoma in rural Myanmar : the Meiktila Eye Study

Aim: To determine the prevalence of glaucoma in the Meiktila district of central, rural Myanmar. Methods: A cross-sectional, population-based survey of inhabitants ⩾40 years of age from villages in Meiktila district, Myanmar, was performed; 2481 eligible participants were identified and 2076 participated in the study. The ophthalmic examination included Snellen visual acuity, slit-lamp examination, tonometry, gonioscopy, dilated stereoscopic fundus examination and full-threshold perimetry. Glaucoma was classified into clinical subtypes and categorised into three levels according to diagnostic evidence. Results: Glaucoma was diagnosed in 1997 (80.5%) participants. The prevalence of glaucoma of any category in at least one eye was 4.9% (95% CI 4.1 to 5.7; n = 101). The overall prevalence of primary angle-closure glaucoma (PACG) was 2.5% (95% CI 1.5 to 3.5) and of primary open-angle glaucoma (POAG) was 2.0% (95% CI 0.9 to 3.1). PACG accounted for 84% of all blindness due to glaucoma, with the majority due to acute angle-closure glaucoma (AACG). Conclusion: The prevalence of glaucoma in the population aged ⩾40 years in rural, central Myanmar was 4.9%. The ratio of PACG to POAG was approximately 1.25:1. PACG has a high visual morbidity and AACG is visually devastating in this community. Screening programmes should be directed at PACG, and further study of the underlying mechanisms of PACG is needed in this population.

Ocular biometry and determinants of refractive error in rural Myanmar: The Meiktila Eye Study.

Objective: To describe the ocular biometry and determinants of refractive error in an adult population in Myanmar. Methods: A cross-sectional, population-based survey of the inhabitants 40 years of age and over from villages in the Meiktila District was performed; 2481 eligible participants were identified, and 2076 participated in the study. Biometric components including axial length (AL), anterior chamber depth (ACD), vitreous chamber depth (VCD), lens thickness (LT) and corneal curvature (CC) were measured. Lens opalescence was measured using the Lens Opacity Grading System III. Non-cycloplegic refraction was measured with an autorefractor. Results: Complete biometric, refractive and lenticular data were available on 1498 participants. Men had longer ALs, ACDs, VCDs and steeper CCs than women. There was an increase in LT, nuclear opalescence (NO) and myopic shift with increasing age, with no significant change in AL with age. In the 40–59 year age group, VCD was a significant predictor of refractive error, but LT (p<0.001) and NO (p<0.001) were stronger predictors. In the 60+ age group, NO (p<0.001) was also the dominant predictor of refractive error. Conclusion: This Burmese population, particularly women, has a relatively short AL and ACD. NO is the strongest predictor of refractive error across all age groups in this population.

Treatment of radiation maculopathy with intravitreal injection of bevacizumab (Avastin).

Purpose: To evaluate the safety and efficacy of intravitreal injection of bevacizumab as a treatment option for radiation maculopathy secondary to plaque radiotherapy. Methods: Interventional case series of five patients who developed radiation maculopathy complicating plaque radiotherapy with ruthenium 106 for choroidal melanoma. One to two intravitreal injections of bevacizumab (0.5 mL) were given, with an interval of 4 weeks between each injection. The main outcome measures were visual acuity and results of clinical ophthalmic examination and optical coherence tomography. Results: Preinjection visual acuity ranged from hand movements to 20/25. The average preinjection central macular thickness measured by optical coherence tomography was 351 &mgr;m. Three of five patients had no improvement in macular edema after treatment with a single injection of bevacizumab at the 2-week follow-up (average postinjection central macular thickness, 287 &mgr;m). Maculopathy in these three patients was long-standing (3–5 years). Improvement in visual acuity occurred in two patients (from 20/30 to 20/25 and from 20/25 to 20/20). Maculopathy in these two patients was diagnosed 1 week before treatment was offered. Resolution of macular edema occurred after a single injection in Patient 4 and after two injections in Patient 5. Patient 4 did not receive direct radiation to the fovea. All but one patient (Patient 5; dose, 8,000 cGy) received a radiation dose of 10,000 cGy to the tumor apex. Conclusions: In this series, treatment of radiation maculopathy with intravitreal injection of bevacizumab was useful in two patients as measured by improvement in visual acuity due to resolution of macular edema. These patients were younger and had macular edema for a shorter duration. One patient did not receive direct radiation to the fovea, and the other had a lower dose of radiation.

Treatment of ocular surface squamous neoplasia with Mitomycin C

Aim To report the outcome of treatment of non-invasive ocular surface squamous neoplasia (or conjunctival-corneal intra-epithelial neoplasia (CCIN)) where topical mitomycin C (MMC) has been used in the treatment regimen. Design Prospective, non-comparative interventional case series. Participants 91 primary or recurrent CCIN lesions from 90 patients treated in a single ocular oncology centre over a 10.5-year period. Intervention 73 cases of localised, non-invasive CCIN and eight cases of recurrent CCIN received a treatment regimen of surgical excision±cryotherapy, followed by two to three 1-week cycles of adjuvant topical MMC (0.04% four times a day). 10 cases of diffuse CCIN received two to three 1-week cycles of topical MMC (0.04% four times a day) as sole primary treatment. Main outcome measure Successful treatment was defined as no clinical recurrence of CCIN. Results Mean follow-up of 56.8 months (range 5.8 to 119.8) and median 57.3 months, revealed no recurrences (0%) in the localised primary group, and one persistent case and two recurrences (30%) in the diffuse primary group. There was one recurrence (12.5%) in the recurrent group, but this was in the only eye with a diffuse type of recurrence. Conclusions MMC treatment following surgical excision appears to decrease the recurrence rate of localised CCIN and should be considered as adjuvant therapy in primary treatment. MMC should also be considered as adjuvant therapy in the treatment of localised recurrent disease. MMC may be used as sole therapy in more diffuse disease, but close ongoing follow-up is recommended in view of the significant risk of persistent or recurrent disease.

Prevalence of refractive error in rural Myanmar: the Meiktila Eye Study.

OBJECTIVE To determine the prevalence of refractive error and associated risk factors in the Meiktila District of central rural Myanmar. DESIGN Population-based cross-sectional study. PARTICIPANTS Randomized stratified cluster sampling of the inhabitants 40 years or older from villages in Meiktila was performed; 2481 eligible participants were identified, 2076 participated in the study, and adequate refractive data were obtained on 1863 individuals (75.1%). METHODS Demographic data including age, gender, and education level were obtained from all participants. The ophthalmic examination included autorefraction, nuclear opalescence (NO) grading at the slit lamp, and applanation tonometry. MAIN OUTCOME MEASURES Refractive errors were classified by type of ametropia and their prevalence was determined. Univariate and multivariate analyses were performed and odds ratios were calculated for the predictors of refractive error within the statistical models. RESULTS Mean refractive error measured -1.3 diopters (D) (standard deviation [SD], 2.9) and mean cylindrical error measured 1.1 D (SD, 1.5). Myopia of >-1.0 and >-6.0 D occurred in 42.7% (95% confidence interval [CI], 40.4%-44.9%) and 6.5% (95% CI, 5.4%-7.6%) of subjects, respectively. Myopic refractive error was associated significantly with a higher degree of NO (P<0.001) and age. Hypermetropia of >+1.0 D occurred in 15% (95% CI, 5.4%-7.6%) of the population and was associated with higher education levels (P<0.001). Astigmatism worse than 1.0 D occurred in 30.6% (95% CI, 28.5%-32.7%) of the population and was associated with age (P<0.001) and NO (P<0.001). CONCLUSION Myopia was more prevalent in older subjects and in those with increased NO. The prevalence rates of myopia in the > or =40 age group are higher than those found in other Asian regions and are likely to contribute to visual impairment.

Homozygous Mutations in PXDN Cause Congenital Cataract, Corneal Opacity, and Developmental Glaucoma

Anterior segment dysgenesis describes a group of heterogeneous developmental disorders that affect the anterior chamber of the eye and are associated with an increased risk of glaucoma. Here, we report homozygous mutations in peroxidasin (PXDN) in two consanguineous Pakistani families with congenital cataract-microcornea with mild to moderate corneal opacity and in a consanguineous Cambodian family with developmental glaucoma and severe corneal opacification. These results highlight the diverse ocular phenotypes caused by PXDN mutations, which are likely due to differences in genetic background and environmental factors. Peroxidasin is an extracellular matrix-associated protein with peroxidase catalytic activity, and we confirmed localization of the protein to the cornea and lens epithelial layers. Our findings imply that peroxidasin is essential for normal development of the anterior chamber of the eye, where it may have a structural role in supporting cornea and lens architecture as well as an enzymatic role as an antioxidant enzyme in protecting the lens, trabecular meshwork, and cornea against oxidative damage.

Cataract surgical coverage and self-reported barriers to cataract surgery in a rural Myanmar population.

Purpose:  The aim of this study is to determine the cataract surgical coverage and investigate the barriers to cataract surgery as reported by those with cataract‐induced visual impairment in rural Myanmar.

Risk factors for primary open‐angle glaucoma in a Burmese population: the Meiktila Eye Study

Purpose:  To report the risk factors associated with primary open‐angle glaucoma (POAG) in the Burmese population.

Cataract in rural Myanmar: prevalence and risk factors from the Meiktila Eye Study

Aims: To determine the prevalence of and risk factors for cataracts in a rural region of central Myanmar. Methods: A cross-sectional, population-based survey of inhabitants ⩾40 years of age from villages of central Myanmar; 2076 participated, and 2044 (82.3%) had an examinable lens in at least one eye. Data recording included smoking history, occupation, education level, betel-nut chewing, height and weight, and dilated lens assessment using Lens Opacities Classification System III grading: nuclear (⩾4), cortical (⩾2) and posterior subcapsular (⩾2) cataracts. Aphakic and pseudophakic eyes were included as operated cataracts for statistical analysis. Results: The prevalence of any cataract including operated eyes was 40.39% (95% CI 37.30 to 43.48%): 27.35% nuclear, 20.91% cortical and 11.34% posterior subcapsular cataracts. No significant association was found between cataract and betel-nut use, gender, smoking or outdoor occupation. The likelihood of all cataract types increased with age (multivariate analysis including operated eyes: OR 1.154, CI 1.13 to 1.18, p<0.001). Low level of education and low body mass index were associated with nuclear cataracts. Large village size was associated with increased risk for nuclear cataract (OR 3.23, CI 1.989 to 5.250, p<0.001) and decreased risk for cortical cataract (OR 0.20, CI 0.08 to 0.47, p<0.001). Conclusions: The prevalence of cataract in rural Myanmar is similar to that in other developing Asian regions. Cataracts are strongly associated with increasing age, and are more common in those with lower education and lower body mass index.