Characteristics of the Corneal Endothelium Across the Primary Angle Closure Disease Spectrum.

Purpose: To evaluate the corneal endothelial characteristics across the primary angle closure (PAC) disease spectrum amongst patients diagnosed as PAC suspects (PACS), PAC, PAC glaucoma (PACG), and previous acute PAC (APAC). Methods: We analyzed a total of 529 subjects (51 PACS, 170 PAC, 234 PACG, and 74 with previous APAC). All subjects had undergone laser peripheral iridotomy prior to study recruitment. Corneal endothelial parameters were measured using a noncontact specular microscope and the following parameters were obtained: mean central endothelial cell density (ECD; cells/mm2), coefficient of variation (CV) in cell area, and percentage of hexagonal cells. Results: The mean age of the subjects was 65.1 ± 8.2 years, and 55.2% were females. The mean central ECD was 2582.0 ± 472.8 cells/mm2 in PACS, 2566.0 ± 408.3 cells/mm2 in PAC, 2523.8 ± 406.8 cells/mm2 in PACG, and 2504.0 ± 558.1 cells/mm2 in APAC, with no significant differences in ECD across the subgroups (P = 0.61). The CV was lowest in PACS (34.38 ± 6.05 µm2/cell), and highest in APAC (37.61 ± 7.98 µm2/cell), but the differences were not significant (P = 0.07). Likewise, the percentage of hexagonality was not significantly different between the groups. A subgroup analysis on the eyes with previous APAC with their fellow eye also showed no significant differences in the corneal endothelial characteristics. Conclusions: The corneal ECD and morphological characteristics such as CV and hexagonality are not significantly different across the PAC disease spectrum. This may reflect the lack of a sustained and/or dramatic IOP insult and/or an insignificant deleterious effect from medications, age, and chronicity on corneal endothelial parameters.

Projection of Eye Disease Burden in Singapore.

INTRODUCTION: Singapore's ageing population is likely to see an increase in chronic eye conditions in the future. This study aimed to estimate the burden of eye diseases among resident Singaporeans stratified for age and ethnicity by 2040. MATERIALS AND METHODS: Prevalence data on myopia, epiretinal membrane (ERM), retinal vein occlusion (RVO), age macular degeneration (AMD), diabetic retinopathy (DR), cataract, glaucoma and refractive error (RE) by age cohorts and educational attainment from the Singapore Epidemiology of Eye Diseases (SEED) study were applied to population estimates from the Singapore population model. RESULTS: All eye conditions are projected to increase by 2040. Myopia and RE will remain the most prevalent condition, at 2.393 million (2.32 to 2.41 million) cases, representing a 58% increase from 2015. It is followed by cataract and ERM, with 1.33 million (1.31 to 1.35 million), representing an 81% increase, and 0.54 million (0.53 to 0.549 million) cases representing a 97% increase, respectively. Eye conditions that will see the greatest increase from 2015 to 2040 in the Chinese are: DR (112%), glaucoma (100%) and ERM (91.4%). For Malays, DR (154%), ERM (136%), and cataract (122%) cases are expected to increase the most while for Indians, ERM (112%), AMD (101%), and cataract (87%) are estimated to increase the most in the same period. CONCLUSION: Results indicate that the burden for all eye diseases is expected to increase significantly into the future, but at different rates. These projections can facilitate the planning efforts of both policymakers and healthcare providers in the development and provision of infrastructure and resources to adequately meet the eye care needs of the population. By stratifying for age and ethnicity, high risk groups may be identified and targeted interventions may be implemented.

Evaluation of Primary Angle-Closure Glaucoma Susceptibility Loci in Patients with Early Stages of Angle-Closure Disease.

PURPOSE: To investigate whether newly identified genetic loci for primary angle-closure glaucoma (PACG) are associated with early stage angle-closure disease defined as primary angle closure suspect (PACS). DESIGN: Case-control study. PARTICIPANTS: A total of 1397 PACS patients and 943 controls of Chinese ethnicity from Singapore and 604 PACS patients and 287 controls of Indian ethnicity. METHODS: The 8 PACG single nucleotide polymorphisms (SNPs; rs11024102 at PLEKHA7, rs3753841 at COL11A1, rs1015213 located between PCMTD1 and ST18 son chromosome 8q, rs3816415 at EPDR1, rs1258267 at CHAT, rs736893 at GLIS3, rs7494379 at FERMT2, and rs3739821 mapping in between DPM2 and FAM102A) were genotyped by Taqman assays. The association between SNP genotypes and PACS status was measured using logistic regression. A P value of 0.006 was set to account for the testing of 8 genetic loci using a Bonferroni correction. A meta-analysis was conducted to calculate the overall P value and accompanying per-allele odds ratios for each SNP analyzed. MAIN OUTCOME MEASURES: Association of PACG loci with PACS status. RESULTS: The PACS patients were significantly older in both cohorts (Chinese, P < 0.001; Indian, P = 0.002), and there were also more women (P < 0.001, both Chinese and Indian cohorts). In the Chinese cohort, significant evidence of association was noted at 3 SNPs: rs1015213 [A] in PCMTD1-ST18 (odds ratio [OR], 2.36; 95% confidence interval [CI], 1.36-4.11; P = 0.002), rs3816415 [A] in EPDR1 (OR, 1.49; 95% CI, 1.19-1.85; P < 0.001), and rs3739821 [G] in DPM2-FAM102A (OR, 1.40; 95% CI, 1.18-1.65; P < 0.001). Only PCMTD1-ST-18 was replicated modestly in the Indian population (P = 0.056). Meta-analysis showed significant evidence of association for PCMTD1-ST-18 (OR, 1.55; 95% CI, 1.18-2.04; P = 0.002) and DPM2-FAM102A (OR, 1.27; 95% CI, 1.12-1.45; P = 0.0002). CONCLUSIONS: In this study, 2 of 8 PACG-associated loci were associated significantly with PACS status, the earliest stage in the angle-closure glaucoma disease course. The association of these PACG loci with PACS status suggests that these loci may confer susceptibility to a narrow angle configuration.

Intraocular pressure change after phacoemulsification in angle-closure eyes without medical therapy.

PURPOSE: To evaluate the intraocular pressure (IOP) change and associated factors 6 months after phacoemulsification in eyes with primary angle-closure suspect (PACS) and eyes with primary angle closure (PAC) that had no medical therapy. SETTING: Singapore National Eye Center, Singapore, Singapore. DESIGN: Retrospective case series. METHODS: Patients with PACS or PAC (with corrected distance visual acuity <20/40) who had uneventful phacoemulsification were recruited. Patients were excluded if they were on IOP-lowering medications within 6 months preoperatively and postoperatively. Preoperative gonioscopy, A-scan biometry, anterior segment optical coherence tomography, and automated refraction were reviewed. Factors related to the percentage of and absolute IOP change were assessed using multiple linear regression analyses after adjusting for age, sex, and diagnosis. RESULTS: The study evaluated 85 patients (85 eyes; 52 PACS, 33 PAC) after 7 eyes (1 PACS, 6 PAC) were excluded because of poor quality imaging. Overall, IOP decreased by 19.9% from the preoperative mean of 16.1 mm Hg ± 3.1 (SD) to 12.9 ± 2.7 mm Hg. The IOP change between the PACS group (-3.3 ± 2.8 mm Hg; -20.6%) and the PAC group (-3.2 ± 4.7 mm Hg; -19.6%) was similar (P > .05). In multiple linear regression analyses, a higher preoperative IOP (ß = 0.68, P < .001) and fewer clock hours of peripheral anterior synechiae (PAS) (ß = -0.30, P = .03) predicted a greater absolute change in and percentage of reduction in IOP, respectively. CONCLUSIONS: The mean IOP reduction 6 months after phacoemulsification was 20%. Less IOP reduction was observed in the presence of lower preoperative IOP and more extensive PAS.

Persistence of Glaucoma Therapy and Visual Field Progression.

PURPOSE: To determine the association of visual field (VF) progression with medication persistence in a cohort on glaucoma therapy. PATIENTS AND METHODS: Pharmacy records were examined over 3 years for patients started on glaucoma monotherapy. A patient was persistent if a prescription was refilled for the same medication < 90 days after the previous prescription had lapsed; otherwise was nonpersistent. Only patients with > 5 reliable VFs within 1-year pretherapy and 6-year posttherapy were included. Progression was analyzed with pointwise linear regression and defined using 2 criteria: (A) ≥ 2 adjacent progressing points (slope P < 0.01) in 1 hemifield; and (B) ≥ 3 progressing points (slope P < 0.01). The mean number and mean slope of progressing points and the mean global slopes were determined. RESULTS: Of 1206 patient eyes (131 persistent, 1075 nonpersistent), 941 were excluded leaving 175 (47 persistent and 128 nonpersistent) for analysis. The mean follow-up durations were 59.3 ± 10.9 and 58.2 ± 9.7 months (P = 0.07) for persistent and nonpersistent eyes, respectively. Overall, 2/47 (4.3%) and 10/128 (7.8%) eyes progressed among persistent and nonpersistent patients, respectively (P = 0.52) using criterion A and 1/47 (2.1%) and 12/128 (9.4%; P = 0.19) eyes using criterion B. Mean number of progressing points (0.3 ± 0.9 vs. 0.7 ± 1.8; P = 0.17), mean slope of progressing points (-2.2 ± 1.1 vs. -2.8 ± 1.3 dB/y; P = 0.27), and mean global slope (0.7 ± 0.5 vs. -0.1 ± 0.8 dB/y; P = 0.07) were similar for persistent and nonpersistent patients, respectively. CONCLUSION: There were small but appreciable differences in VF progression rates between persistent and nonpersistent patient eyes on glaucoma drops, but differences were not significant.

Anterior Chamber Angle and Intraocular Pressure Changes After Phacoemulsification: A Comparison Between Eyes With Closed-angle and Open-angle Glaucoma.

PURPOSE: To compare the angle and intraocular pressure (IOP) changes after phacoemulsification between eyes with closed-angle or open-angle glaucoma. METHODS: Angle measurements using Visante AS-OCT imaging was performed for a prospective cohort of 24 subjects with closed-angle and 30 subjects with open-angle glaucoma before and 3 months after phacoemulsification. IOP measurement was measured at 6 and 12 months after surgery using Goldmann applanation tonometry as secondary outcome measures. RESULTS: Eyes with closed angles were smaller than those with open angles (mean axial length 22.88 vs. 24.11 mm, P<0.001). Mean anterior chamber depth, area, volume, AOD500, AOD750, ARA, TISA500, and TISA750 increased after phacoemulsification in all eyes regardless of preexisting angle status (all P<0.001). Increase in AOD500, AOD750, TISA500, and TISA750 were greater in eyes with open angles compared with closed angles (P=0.03, 0.04. 0.04, 0.04, respectively). Mean IOP decreased by 1.8 and 2.1 mm Hg at 6 and 12 months, respectively, after phacoemulsification for all eyes (P<0.001 for both timepoints compared with preoperative baseline). However, postoperative reduction in the mean IOP was not significantly different between eyes with closed and open angles (Mann-Whitney test P=0.32 at 6 mo and P=0.75 at 12 mo postsurgery compared with preoperative). CONCLUSIONS: Angle opening postphacoemulsification was considerable in all eyes. A similar IOP reduction after phacoemulsification was observed in all eyes regardless of angle status.

Future requirements for and supply of ophthalmologists for an aging population in Singapore.

BACKGROUND: Singapore's population, as that of many other countries, is aging; this is likely to lead to an increase in eye diseases and the demand for eye care. Since ophthalmologist training is long and expensive, early planning is essential. This paper forecasts workforce and training requirements for Singapore up to the year 2040 under several plausible future scenarios. METHODS: The Singapore Eye Care Workforce Model was created as a continuous time compartment model with explicit workforce stocks using system dynamics. The model has three modules: prevalence of eye disease, demand, and workforce requirements. The model is used to simulate the prevalence of eye diseases, patient visits, and workforce requirements for the public sector under different scenarios in order to determine training requirements. RESULTS: Four scenarios were constructed. Under the baseline business-as-usual scenario, the required number of ophthalmologists is projected to increase by 117% from 2015 to 2040. Under the current policy scenario (assuming an increase of service uptake due to increased awareness, availability, and accessibility of eye care services), the increase will be 175%, while under the new model of care scenario (considering the additional effect of providing some services by non-ophthalmologists) the increase will only be 150%. The moderated workload scenario (assuming in addition a reduction of the clinical workload) projects an increase in the required number of ophthalmologists of 192% by 2040. Considering the uncertainties in the projected demand for eye care services, under the business-as-usual scenario, a residency intake of 8-22 residents per year is required, 17-21 under the current policy scenario, 14-18 under the new model of care scenario, and, under the moderated workload scenario, an intake of 18-23 residents per year is required. CONCLUSIONS: The results show that under all scenarios considered, Singapore's aging and growing population will result in an almost doubling of the number of Singaporeans with eye conditions, a significant increase in public sector eye care demand and, consequently, a greater requirement for ophthalmologists.

Graft failure and intraocular pressure control after keratoplasty in iridocorneal endothelial syndrome.

PURPOSE: To describe and compare graft survival and intraocular pressure (IOP) control after penetrating keratoplasty (PK) and Descemet stripping automated endothelial keratoplasty (DSAEK) in eyes with iridocorneal endothelial (ICE) syndrome. DESIGN: Retrospective case series. METHODS: Multicenter study conducted at the Singapore National Eye Centre (SNEC) and Price Vision Group. Twenty-nine consecutive eyes with ICE syndrome that underwent keratoplasty between 1991 and 2011 were identified from the SNEC transplant database and Price Vision Group patient database and the following data extracted: demographics, graft failure, IOP indices, and glaucoma treatment pre- and postkeratoplasty. The main outcome measures were graft failure and need for additional IOP-lowering treatment after keratoplasty. RESULTS: The mean follow-up duration was 7.0 ± 4.9 years in the PK group (n = 17) and 4.0 ± 2.6 years in the DSAEK group (n = 12). After a mean of 4.1 ± 3.1 years, 37.9% of grafts (11/29) failed: 7 PK compared to 4 DSAEK (P = .72). The graft failure rate was 50% in eyes with prekeratoplasty glaucoma surgery vs 31.6% in those without (P = .43). Additional glaucoma treatment was required in 37.9% of eyes (11/29): 41.2% of PK eyes and 50% of DSAEK eyes (P = .28) Eyes that had undergone glaucoma surgery before keratoplasty were less likely to require escalation of IOP-lowering therapy postkeratoplasty (9.1% vs 50%, P = .03). CONCLUSIONS: One-third of grafts failed after keratoplasty for ICE syndrome at a mean duration of 4 years and additional IOP-lowering treatment was required in 37.9%. Both PK and DSAEK had similar outcomes with regard to graft failure and IOP control.

Comparison of two spectral domain optical coherence tomography devices for angle-closure assessment.

PURPOSE: To compare two spectral domain optical coherence tomography (SD-OCT) devices for the identification of angle structures and the presence of angle closure. METHODS: This was a prospective comparative study. Consecutive patients underwent gonioscopy and anterior segment imaging using two SD-OCT devices (iVue and Cirrus). Images were evaluated for the ability to detect angle structures such as Schwalbe's line (SL), trabecular meshwork (TM), Schlemm's canal (SC), and scleral spur (SS), and the presence of angle closure. Angle closure was defined as iris contact with the angle wall anterior to the SS on SD-OCT, and nonvisibility of the posterior TM on gonioscopy. Angle closure in an eye was defined as ≥two quadrants of closed angles. AC1 statistic was used to assess the agreement between devices. RESULTS: Of the 69 subjects studied (46.4% male, 84.1% Chinese, mean age 64.0 ± 10.5 years), 40 subjects (40 eyes, 58.0%) had angle closure on gonioscopy. The most identifiable structure on Cirrus SD-OCT was the SS (82.2%) and SL on iVue SD-OCT (74.5%). Angle closure was indeterminable in 14.5% and 50.7% of Cirrus and iVue scans (P < 0.001), respectively. Interdevice agreement for angle closure was moderately strong (AC1 = 0.67), but agreement with gonioscopy was only fair (AC1 = 0.35 and 0.50 for Cirrus and iVue, respectively). CONCLUSIONS: It was more difficult to determine angle closure status with iVue compared with Cirrus SD-OCT. There was fair agreement between both devices with gonioscopy for identifying angle closure.

Pseudophakic rhegmatogenous retinal detachment in a large Asian tertiary eye centre: a cohort study.

BACKGROUND: To determine the incidence and identify risk factors for the development of rhegmatogenous retinal detachment in patients who had cataract surgery at the Singapore National Eye Centre between 2001 and 2003. DESIGN: Retrospective case-control study. PARTICIPANTS: All patients who had cataract surgery between 2001 and 2003 and subsequently retinal detachment surgery in the same eye, between 2001 and June 2008, at Singapore National Eye Centre. METHODS: Review of case records. MAIN OUTCOME MEASURES: Incidence of posterior capsular rupture and retinal detachment. RESULTS: Thirty-nine eyes, out of 24 846 cataract operations performed between 2001 and 2003, developed rhegmatogenous retinal detachment in the follow-up period from 2001 to 2008 (cumulative incidence 0.16%, 95% confidence interval 0.11-0.21%). Of the 508 eyes with posterior capsular rupture during cataract surgery, nine developed retinal detachment (cumulative incidence 1.77%, 95% confidence interval 0.87-3.23%). Men were more likely to develop retinal detachment (P < 0.001). On Kaplan-Meier survival analysis, younger patients had a higher probability of retinal detachment in comparison with older subjects (P < 0.001). Similarly, eyes with posterior capsular rupture during surgery had shorter interval duration to retinal detachment, compared with eyes that did not (P = 0.002). When compared with patients more than 70 years of age, younger patients had significantly higher hazard ratios of retinal detachment (hazard ratio 19.7, 95% confidence interval 3.6-107.3, P < 0.05). CONCLUSION: The incidence of pseudophakic retinal detachment in our institution is low. Posterior capsular rupture during surgery, men and younger age at time of surgery increases the risk of developing retinal detachment, and careful observation for the occurrence of retinal detachment may be warranted in these groups of patients.

Microsporidial keratoconjunctivitis in the tropics: a case series.

PURPOSE: To present a series of microsporidial keratoconjunctivitis in 24 eyes. METHODS: Retrospective non-comparative observational case series. Medical records were retrieved and individuals evaluated based on symptoms, risk factors, visual acuity, slit lamp biomicroscopy and pathological examination of cornea epithelial scrapings. Demographic features, clinical course, predisposing factors, microbiological profile, treatment, final clinical outcome and visual acuity were recorded. RESULTS: Of the 22 patients, 90.9% were men, with a mean age of 30.3 years (range 15 - 76 years). Two (9.1%) had bilateral involvement, 15 (68.2%) were non-contact lens users, 17 (77.3%) reported contamination with mud within 2 weeks (mean 6.8 days) of onset of symptoms. All patients presented with conjunctivitis and coarse, multifocal, punctate epithelial keratitis. Two out of 24 eyes (8.3%) had anterior stromal infiltrates, while 8 (33.3%) had anterior uveitis. Microsporidial spores were identified on modified trichrome staining of corneal epithelial scrapes in all eyes. All eyes were treated with epithelial debridement, topical fluoroquinolone and hexamidine diisethionate, 7 (31.8%) patients received oral albendazole, and all eyes with anterior uveitis received topical steroids. All cases resolved without visually significant sequelae. CONCLUSION: Microsporidial keratoconjunctivitis occurred mainly in males, is usually unilateral, presents as conjunctivitis and coarse, multifocal, punctate epithelial keratitis, and may incite anterior uveitis. Soil contamination is an important risk factor. Treatment with debridement, fluoroquinolones, hexamidine diisethionate with or without systemic albendazole is effective, with steroids reserved for any associated anterior uveitis.

Blindness and long-term progression of visual field defects in chinese patients with primary angle-closure glaucoma.

PURPOSE: To investigate the long-term rates of blindness and visual field (VF) progression in treated primary angle-closure glaucoma (PACG) patients. DESIGN: Retrospective observational case series. METHODS: PACG patients with ≥10 years of follow-up were analyzed. All VFs (static automated perimetry, central 24-2 threshold test) performed were reviewed and reliable VFs (fixation losses <20%, false positives and false negatives <33%) were scored using the Advanced Glaucoma Intervention Study (AGIS) system. Progression of a VF defect was defined as a change of ≥4 from baseline on 2 consecutive VF tests. RESULTS: From the 137 eyes of 87 patients with PACG with ≥10 years of follow-up identified, 6% and 30.1% were blind based on initial visual acuity (VA) and VF criteria respectively and 12.0% had an initial AGIS score of 20; these were excluded. Eighty-three eyes from 57 patients (all Chinese, mean age 59.9 ± 8.2 years, 67.5% female) were analyzed. The mean AGIS score was 5.14 ± 4.37 at baseline. VF deterioration was detected in 27 eyes (32.5%) of 21 patients, with 4.8% and 7.2% of eyes progressing to blindness based on VA and VF criteria respectively. On Cox regression, eyes with VF progression had higher mean overall IOP (P < .001), and higher prevalence of previous acute angle closure (AAC, P = .008). CONCLUSIONS: Over 10 years, a third of PACG patients were found to have VF progression, with 7% progressing to blindness while on treatment. Eyes with higher mean overall IOP and a history of previous AAC were more likely to have VF progression.

Corneal graft survival and intraocular pressure control after descemet stripping automated endothelial keratoplasty in eyes with pre-existing glaucoma.

PURPOSE: To describe the effect of Descemet stripping automated endothelial keratoplasty (DSAEK) on intraocular pressure (IOP) and corneal graft survival in eyes with pre-existing glaucoma or ocular hypertension. DESIGN: Retrospective, observational case series. METHODS: We performed a retrospective review of 184 eyes that underwent DSAEK from January 2007 through May 2009 at the Singapore National Eye Centre. Eyes with pre-existing glaucoma or ocular hypertension that underwent DSAEK were included, whereas those with a follow-up period of less than 12 months were excluded. Main outcome measures were graft failure and need for additional IOP-lowering treatment after DSAEK. RESULTS: Forty-seven eyes (51% male; mean age, 66.6 years) with glaucoma underwent DSAEK and were followed-up for a mean of 27.3 ± 8.5 months. Before DSAEK, 60% were taking at least 1 topical IOP-lowering medication, whereas 14 eyes (30%) previously had undergone glaucoma filtration surgery. After DSAEK, visual acuity improved by a mean of 5.4 ± 3.7 Snellen lines. Seventeen percent of grafts failed at a mean of 12.8 ± 7.0 months. The mean IOP increased by 2.1 mm Hg to 16.0 ± 2.5 mm Hg, with 62% requiring additional IOP-lowering treatment and 28% needing filtration surgery at a mean of 9.3 months after DSAEK. Eyes without prior filtration surgery and eyes that underwent additional intraoperative procedures during DSAEK were 10 and 18 times more likely to require IOP-lowering treatment after DSAEK (P = .002 and P = .008), respectively. CONCLUSIONS: With prompt and appropriate intervention, IOP in glaucomatous eyes undergoing DSAEK can be controlled with minimal increase after DSAEK. Eyes with previous filtration surgery require fewer medications to control elevated IOP than eyes that have not had previous surgery.

Risk factors for poor visual outcome following cataract surgery in Vogt-Koyanagi-Harada disease.

AIM: To determine risk factors for poor visual outcome following cataract surgery in Vogt-Koyanagi-Harada (VKH) disease. METHODS: Retrospective review of all VKH patients who underwent cataract surgery, for demographics, initial corticosteroid dose, treatment outcome, quiescence at time of cataract surgery, perioperative corticosteroid prophylaxis, preoperative best-corrected visual acuity (BCVA), cataract surgery technique, intraocular lens implanted, additional surgical procedures, complications and BCVA at 6 and 12 months postsurgery. RESULTS: 28 of 105 VKH patients (50 eyes) had cataract surgery. The mean age at surgery was 55 ± 13 years. The mean duration of postoperative follow-up was 89.8 months (range 8-252 months). At 12 months postsurgery, no patients lost more than two lines of their preoperative acuity. Forty-one eyes (82%) improved by two or more Snellen lines. Thirty-four eyes (68%) had a BCVA of 20/40 or better. Sixteen eyes (32%) had a poor visual acuity, nine (18%) from pre-existing macular lesions, two from cystoid macular oedema, one from posterior capsule opacification and four from disease recurrence. Recurrent inflammation was the only significant risk factor for poor visual outcome (p=0.004, χ(2) test). CONCLUSION: Recurrent inflammation is a critical poor prognostic factor for cataract surgery in VKH, but with appropriate management, good visual outcomes can be achieved.

Persistence of patients receiving topical glaucoma monotherapy in an Asian population.

OBJECTIVE: To determine the persistence rates of patients who started taking topical intraocular pressure (IOP)-lowering monotherapy in a Singapore eye hospital. METHODS: This was a retrospective review of patients who started taking a single IOP-lowering medication between October 1, 2005, and September 30, 2006. Pharmacy dispensing records were traced for 3 years from the date of first prescription. A patient was defined as persistent if he or she was prescribed the same medication before or within 90 days after the previous prescription had lapsed during this period. Persistence was assessed after 1 and 3 years. RESULTS: A total of 2781 patients started taking topical IOP-lowering monotherapy during the 1-year study period. The mean (SD) age was 61.1 (15.7) years; 50.2% were male, and most were Chinese (81.1%) or Singaporean residents (85.4%). After 1 year, only 22.5% of patients (626 of 2781) persistently received the same therapy, which decreased to 11.5% (320 of 2781) after 3 years. Prostaglandin analogues had better persistence rates at 1 year compared with timolol maleate (29.6% vs 23.7%; P = .004) and all other medications combined (29.6% vs 20.6%; P < .001). Those who were not persistent at year 1 were younger (P < .001) and more likely to not be Singaporean (P = .008), not receiving government subsidies (P < .001), and receiving unilateral therapy (P < .001). CONCLUSIONS: In this hospital-based study, the persistence rate of patients who started taking topical IOP-lowering monotherapy was low after 1 (22.5%) and 3 years (11.5%). These rates are lower than in previous studies in Western countries and may have implications for glaucoma care in Singapore and other parts of Asia.

Angle imaging: advances and challenges.

Primary angle closure glaucoma (PACG) is a major form of glaucoma in large populous countries in East and South Asia. The high visual morbidity from PACG is related to the destructive nature of the asymptomatic form of the disease. Early detection of anatomically narrow angles is important and the subsequent prevention of visual loss from PACG depends on an accurate assessment of the anterior chamber angle (ACA). This review paper discusses the advantages and limitations of newer ACA imaging technologies, namely ultrasound biomicroscopy, Scheimpflug photography, anterior segment optical coherence tomography and EyeCam, highlighting the current clinical evidence comparing these devices with each other and with clinical dynamic indentation gonioscopy, the current reference standard.

Demonstration of angle widening using EyeCam after laser peripheral iridotomy in eyes with angle closure.

PURPOSE: To evaluate EyeCam in detecting changes in angle configuration after laser peripheral iridotomy (LPI) in comparison to gonioscopy, the reference standard. DESIGN: Prospective comparative study. METHODS: Twenty-four subjects (24 eyes) with primary angle-closure glaucoma (PACG) were recruited. Gonioscopy and EyeCam (Clarity Medical Systems) imaging of all 4 angle quadrants were performed, before and 2 weeks after LPI. Images were graded according to angle structures visible by an observer masked to clinical data or the status of LPI, and were performed in a random order. Angle closure in a quadrant was defined as the inability to visualize the posterior trabecular meshwork. We determined the number of quadrants with closed angles and the mean number of clock hours of angle closure before and after LPI in comparison to gonioscopy. RESULTS: Using EyeCam, all 24 eyes showed at least 1 quadrant of angle widening after LPI. The mean number of clock hours of angle closure decreased significantly, from 8.15 +/- 3.47 clock hours before LPI to 1.75 +/- 2.27 clock hours after LPI (P < .0001, Wilcoxon signed rank test). Overall, gonioscopy showed 1.0 +/- 1.41 (95% CI, 0.43-1.57) quadrants opening from closed to open after LPI compared to 2.0 +/- 1.28 (95% CI, 1.49-2.51, P = .009) quadrants with EyeCam. Intra-observer reproducibility of grading the extent of angle closure in clock hours in EyeCam images was moderate to good (intraclass correlation coefficient 0.831). CONCLUSIONS: EyeCam may be used to document changes in angle configuration after LPI in eyes with PACG.

Plateau iris in Asian subjects with primary angle closure glaucoma.

OBJECTIVE: To determine the prevalence of plateau iris in Asian eyes with primary angle closure glaucoma (PACG) using ultrasound biomicroscopy (UBM). METHODS: In this cross-sectional observational study, subjects older than 40 years with PACG who had a patent laser peripheral iridotomy underwent UBM in 1 eye. Ultrasound biomicroscopy images were qualitatively analyzed using standardized criteria. Plateau iris in a quadrant was defined by anteriorly directed ciliary body, absent ciliary sulcus, steep iris root from its point of insertion followed by a downward angulation, flat iris plane, and irido-angle contact. At least 2 quadrants had to fulfill these UBM criteria for an eye to be classified as having plateau iris. RESULTS: One hundred eleven subjects (70 from Singapore, 41 from Thailand) with PACG were recruited. The mean (SD) age was 65.6 (8.1) years, and 63.9% were female. Based on standardized UBM criteria, plateau iris was found in 36 of 111 eyes (32.4%; 95% confidence interval, 24.4%-41.6%). In these 36 eyes, quadrant-wise analysis showed 66.7% had plateau iris in 2 quadrants; 22.2%, in 3 quadrants; and 11.1%, in all quadrants. CONCLUSIONS: About 30% of PACG eyes with a patent laser peripheral iridotomy were found to have plateau iris on UBM, highlighting the importance of non-pupil block mechanisms in Asian individuals.

Confirmation of the presence of uveal effusion in Asian eyes with primary angle closure glaucoma: an ultrasound biomicroscopy study.

OBJECTIVE: To confirm the presence of uveal effusion in the eyes of Asian patients with primary angle closure glaucoma (PACG) using ultrasound biomicroscopy (UBM). METHODS: In this observational case series, 70 patients with PACG (28 untreated patients with newly diagnosed PACG and 42 patients who had undergone previous laser iridotomy and were being monitored) and 12 patients with acute primary angle closure (APAC) were recruited. Eyes of patients with newly diagnosed PACG and APAC underwent UBM before and after laser iridotomy, whereas eyes of patients with treated PACG underwent UBM at enrollment. Uveal effusion was defined as a clear space between the choroid and sclera and was graded as follows: grade 0, none; grade 1, slitlike; grade 2, bandlike; and grade 3, obvious. RESULTS: Overall, uveal effusion was found in 11 of 70 eyes with PACG (15.7%; 95% confidence interval, 8.8%-26.2%) and in 3 of 12 eyes with APAC (25%; 95% confidence interval, 8.0%-53.4%). For patients with newly diagnosed PACG, uveal effusion was found in 4 of 28 eyes (14.2%; 95% confidence interval, 5.1%-32.1%) before laser iridotomy; 2 eyes had effusion after laser iridotomy. When present, the effusion was grade 1 in PACG eyes and grade 2 or 3 in APAC eyes. CONCLUSIONS: Uveal effusion was present in a significant proportion of Asian eyes with PACG and APAC, confirming a recent report of this finding.