David S. Friedman

Prevalence of age-related macular degeneration in the United States

OBJECTIVE To estimate the prevalence and distribution of age-related macular degeneration (AMD) in the United States by age, race/ethnicity, and gender. METHODS Summary prevalence estimates of drusen 125 microm or larger, neovascular AMD, and geographic atrophy were prepared separately for black and white persons in 5-year age intervals starting at 40 years. The estimated rates were based on a meta-analysis of recent population-based studies in the United States, Australia, and Europe. These rates were applied to 2000 US Census data and to projected US population figures for 2020 to estimate the number of the US population with drusen and AMD. RESULTS The overall prevalence of neovascular AMD and/or geographic atrophy in the US population 40 years and older is estimated to be 1.47% (95% confidence interval, 1.38%-1.55%), with 1.75 million citizens having AMD. The prevalence of AMD increased dramatically with age, with more than 15% of the white women older than 80 years having neovascular AMD and/or geographic atrophy. More than 7 million individuals had drusen measuring 125 microm or larger and were, therefore, at substantial risk of developing AMD. Owing to the rapidly aging population, the number of persons having AMD will increase by 50% to 2.95 million in 2020. Age-related macular degeneration was far more prevalent among white than among black persons. CONCLUSION Age-related macular degeneration affects more than 1.75 million individuals in the United States. Owing to the rapid aging of the US population, this number will increase to almost 3 million by 2020.

Possible mechanisms of primary angle-closure and malignant glaucoma

POPULATION STUDIES AND RISK FACTORSDuring the last 5 years, population-based prevalence surveys, large-scale clinical evaluations, and technological advances in diagnostic methods have contributed to our understanding of primary angle-closure glaucoma (PACG). During the early 20th century, the assoc

Glaucoma in a rural population of southern India: The Aravind comprehensive eye survey

PURPOSE To determine the prevalence of glaucoma and risk factors for primary open-angle glaucoma in a rural population of southern India. DESIGN A population-based cross-sectional study. PARTICIPANTS A total of 5150 subjects aged 40 years and older from 50 clusters representative of three southern districts of Tamil Nadu in southern India. METHODS All participants had a comprehensive eye examination at the base hospital, including visual acuity using logarithm of the minimum angle of resolution illiterate E charts and refraction, slit-lamp biomicroscopy, gonioscopy, applanation tonometry, dilated fundus examinations, and automated central 24-2 full-threshold perimetry. MAIN OUTCOME MEASURES Definite primary open-angle glaucoma (POAG) was defined as angles open on gonioscopy and glaucomatous optic disc changes with matching visual field defects, whereas ocular hypertension was defined as intraocular pressure (IOP) greater than 21 mmHg without glaucomatous optic disc damage and visual field defects in the presence of an open angle. Manifest primary angle-closure glaucoma (PACG) was defined as glaucomatous optic disc damage or glaucomatous visual field defects with the anterior chamber angle partly or totally closed, appositional angle closure or synechiae in the angle, and absence of signs of secondary angle closure. Secondary glaucoma was defined as glaucomatous optic nerve damage and/or visual field abnormalities suggestive of glaucoma with ocular disorders that contribute to a secondary elevation in IOP. RESULTS The prevalence (95% confidence interval) of any glaucoma was 2.6% (2.2, 3.0), of POAG it was 1.7% (1.3, 2.1), and if PACG it was 0.5% (0.3, 0.7), and secondary glaucoma excluding pseudoexfoliation was 0.3% (0.2,0.5). On multivariate analysis, increasing age, male gender, myopia greater than 1 diopter, and pseudoexfoliation were significantly associated with POAG. After best correction, 18 persons (20.9%) with POAG were blind in either eye because of glaucoma, including 6 who were bilaterally blind and an additional 12 persons with unilateral blindness because of glaucomatous optic neuropathy in that eye. Of those identified with POAG, 93.0% had not been previously diagnosed with POAG. CONCLUSIONS The prevalence of glaucoma in this population is not lower than that reported for white populations elsewhere. A large proportion of those with POAG had not been previously diagnosed. One fifth of those with POAG had blindness in one or both eyes from glaucoma. Early detection of glaucoma in this population will reduce the burden of blindness in India.

Racial differences in the prevalence of age-related macular degeneration: The Baltimore Eye Survey

OBJECTIVE To determine the prevalence of age-related macular degeneration (AMD) and signs of age-related maculopathy in a population-based sample of blacks and whites 40 years of age or older from East Baltimore. DESIGN Cross-sectional population-based study. PARTICIPANTS A total of 5308 black and white subjects received a screening eye examination that included fundus photography. MAIN OUTCOME MEASURES Stereoscopic color fundus photographs were graded for the presence and severity of drusen, pigmentary abnormalities, geographic atrophy, and choroidal neovascularization in the macula. RESULTS Drusen > or = 64 microm were identified in about 20% of individuals in both groups, but large drusen (>125 microm) were more common among older whites (15% for whites versus 9% for blacks over 70). Pigmentary abnormalities were also more common among older whites (7.9% for whites versus 0.4% for blacks over 70). Age-related macular degeneration was more prevalent among whites than blacks. The prevalence of AMD was 2.1 % among whites over 70 years of age. No cases of AMD were detected among 243 black subjects in this age group. Logistic regression adjusting for age, sex and smoking (current, former, or never) detected an odds ratio of 4.4 (95% confidence interval: 1.5-12.4) for whites with AMD compared with blacks. CONCLUSION Although drusen are common in both blacks and whites over the age of 40, more severe forms of age-related maculopathy and late AMD are more prevalent in older whites.

Prevalence of Amblyopia and Strabismus in White and African-American Children Aged 6 through 71 Months: The Baltimore Pediatric Eye Disease Study

OBJECTIVE To determine the age-specific prevalence of strabismus in white and African American children aged 6 through 71 months and of amblyopia in white and African American children aged 30 through 71 months. DESIGN Cross-sectional, population-based study. PARTICIPANTS White and African American children aged 6 through 71 months in Baltimore, MD, United States. Among 4132 children identified, 3990 eligible children (97%) were enrolled and 2546 children (62%) were examined. METHODS Parents or guardians of eligible participants underwent an in-home interview and were scheduled for a detailed eye examination, including optotype visual acuity and measurement of ocular deviations. Strabismus was defined as a heterotropia at near or distance fixation. Amblyopia was assessed in those children aged 30 through 71 months who were able to perform optotype testing at 3 meters. MAIN OUTCOME MEASURES The proportions of children aged 6 through 71 months with strabismus and of children aged 30 through 71 months with amblyopia. RESULTS Manifest strabismus was found in 3.3% of white and 2.1% of African American children (relative prevalence [RP], 1.61; 95% confidence interval [CI], 0.97-2.66). Esotropia and exotropia each accounted for close to half of all strabismus in both groups. Only 1 case of strabismus was found among 84 white children 6 through 11 months of age. Rates were higher in children 60 through 71 months of age (5.8% for whites and 2.9% for African Americans [RP, 2.05; 95% CI, 0.79-5.27]). Amblyopia was present in 12 (1.8%) white and 7 (0.8%) African American children (RP, 2.23; 95% CI, 0.88-5.62). Only 1 child had bilateral amblyopia. CONCLUSIONS Manifest strabismus affected 1 in 30 white and 1 in 47 African American preschool-aged children. The prevalence of amblyopia was <2% in both whites and African Americans. National population projections suggest that there are approximately 677,000 cases of manifest strabismus among children 6 through 71 months of age and 271 000 cases of amblyopia among children 30 through 71 months of age in the United States.

Common Variants at 9p21 and 8q22 Are Associated with Increased Susceptibility to Optic Nerve Degeneration in Glaucoma

Optic nerve degeneration caused by glaucoma is a leading cause of blindness worldwide. Patients affected by the normal-pressure form of glaucoma are more likely to harbor risk alleles for glaucoma-related optic nerve disease. We have performed a meta-analysis of two independent genome-wide association studies for primary open angle glaucoma (POAG) followed by a normal-pressure glaucoma (NPG, defined by intraocular pressure (IOP) less than 22 mmHg) subgroup analysis. The single-nucleotide polymorphisms that showed the most significant associations were tested for association with a second form of glaucoma, exfoliation-syndrome glaucoma. The overall meta-analysis of the GLAUGEN and NEIGHBOR dataset results (3,146 cases and 3,487 controls) identified significant associations between two loci and POAG: the CDKN2BAS region on 9p21 (rs2157719 [G], OR = 0.69 [95%CI 0.63–0.75], p = 1.86×10−18), and the SIX1/SIX6 region on chromosome 14q23 (rs10483727 [A], OR = 1.32 [95%CI 1.21–1.43], p = 3.87×10−11). In sub-group analysis two loci were significantly associated with NPG: 9p21 containing the CDKN2BAS gene (rs2157719 [G], OR = 0.58 [95% CI 0.50–0.67], p = 1.17×10−12) and a probable regulatory region on 8q22 (rs284489 [G], OR = 0.62 [95% CI 0.53–0.72], p = 8.88×10−10). Both NPG loci were also nominally associated with a second type of glaucoma, exfoliation syndrome glaucoma (rs2157719 [G], OR = 0.59 [95% CI 0.41–0.87], p = 0.004 and rs284489 [G], OR = 0.76 [95% CI 0.54–1.06], p = 0.021), suggesting that these loci might contribute more generally to optic nerve degeneration in glaucoma. Because both loci influence transforming growth factor beta (TGF-beta) signaling, we performed a genomic pathway analysis that showed an association between the TGF-beta pathway and NPG (permuted p = 0.009). These results suggest that neuro-protective therapies targeting TGF-beta signaling could be effective for multiple forms of glaucoma.

Choroidal Thickness Measured by Spectral Domain Optical Coherence Tomography: Factors Affecting Thickness in Glaucoma Patients

PURPOSE To measure choroidal thickness and to determine parameters associated with it. DESIGN Cross-sectional study. PARTICIPANTS Seventy-four glaucoma patients and glaucoma suspects. METHODS Spectral domain optical coherence tomography (SD-OCT) scans were obtained to estimate average choroidal thickness in a group of glaucoma suspects and glaucoma patients. The average thickness was calculated from enhanced depth SD-OCT images and manually analyzed with Image J software. Open-angle glaucoma, open-angle glaucoma suspect, primary angle-closure glaucoma, primary angle closure, and primary angle-closure suspect were defined by published criteria. Glaucoma suspects had normal visual fields bilaterally. Glaucoma was defined by specific criteria for optic disc damage and visual field loss in ≥1 eye. The most affected eye was analyzed for comparisons across individuals, and right/left and upper half/lower half comparisons were made to compare thickness against degree of visual field damage. MAIN OUTCOME MEASURES Average macular and peripapillary choroidal thickness measured using SD-OCT. RESULTS The choroidal-scleral interface was visualized in 86% and 96% of the macular and peripapillary scans, respectively. In multivariable linear regression analysis, the macular choroid was significantly thinner in association with 4 features: Longer eyes (22 μm per mm longer [95% confidence interval (CI), -33, -11]), older individuals (31 μm thinner per decade older [95% CI, -44, -17]), lower diastolic ocular perfusion pressure (26 μm thinner per 10 mmHg lower [95% CI, 8, 44]), and thicker central corneas (6 μm per 10 μm thicker cornea [95% CI, -10, 0]). The choroid was not significantly thinner in glaucoma patients than in suspects (14 μm [95% CI, -54, 26]; P = 0.5). Peripapillary choroidal thickness was not significantly different between glaucoma and suspect patients. Thickness was not associated with damage severity as estimated by visual field mean deviation or nerve fiber layer thickness, including comparisons of right with left eye or upper with lower values. CONCLUSIONS Age, axial length, CCT, and diastolic ocular perfusion pressure are significantly associated with choroidal thickness in glaucoma suspects and glaucoma patients. Degree of glaucoma damage was not consistently associated with choroidal thickness. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.

Doctor–Patient Communication, Health-Related Beliefs, and Adherence in Glaucoma : Results from the Glaucoma Adherence and Persistency Study

OBJECTIVE To use multiple data sources to determine drivers of patient adherence to topical ocular hypotensive therapy. DESIGN Retrospective database and chart reviews in combination with prospective patient surveys. Diverse medical environments where insured patients in the research database seek care. PARTICIPANTS Three hundred patients with a new claim diagnosis for open-angle glaucoma who initially were prescribed one of three prostaglandins and 103 physicians participating in the same medical plans. METHODS A structured interview addressing self-reported adherence, experiences with medication, communication with the physician, and health-related beliefs associated with adherence behavior was administered to surveyed patients. Phone interviews were conducted with participating ophthalmologists. MAIN OUTCOME MEASURE Of adherence, medication possession ratio. RESULTS Eight variables were associated independently with a lower medication possession ratio: (1) hearing all of what you know about glaucoma from your doctor (compared with some or nothing); (2) not believing that reduced vision is a risk of not taking medication as recommended; (3) having a problem paying for medications; (4) difficulty while traveling or away from home; (5) not acknowledging stinging and burning; (6) being nonwhite; (7) receiving samples; and (8) not receiving a phone call visit reminder. The multivariate model explained 21% of the variance. CONCLUSIONS These findings indicate that doctor-patient communications and health-related beliefs of patients contribute to patient adherence. Patient learning styles that are associated with less concern about the future effects of glaucoma and the risks of not taking medications are associated with lower adherence. Specifically, knowledge about potential vision loss from glaucoma is a critical element that tends to be missed by more passive doctor-dependent patients who tend to be poorly adherent. These findings suggest that educational efforts in the office may improve patient adherence to medical therapies.

Adherence with Topical Glaucoma Medication Monitored Electronically: The Travatan Dosing Aid Study

PURPOSE To assess patient adherence and behaviors with topical once-daily therapy for glaucoma. DESIGN Prospective, observational cohort study. PARTICIPANTS One hundred ninety-six patients with glaucoma who were being treated with a prostaglandin analog in 1 or both eyes at the Scheie or Wilmer Eye Institutes between August 2006 and June 2007. METHODS Detailed medical history was obtained from each patient. All subjects used the Travatan Dosing Aid (DA; Alcon, Fort Worth, TX) to administer travoprost as prescribed. Devices were collected at 3 months and the data of drop usage was downloaded using software provided with the dosing aid. Data were analyzed for the 8-week period starting 2 weeks after the enrollment visit and ending 2 weeks before the 3-month visit. MAIN OUTCOME MEASURES Assessment of adherence and patterns of drop usage as indicated by the DA. RESULTS A total of 282 subjects consented to be in the study and 86 (30%) withdrew before study completion or had device errors, leaving 196 subjects (70%) with evaluable data at 3 months. The overall mean (+/-standard deviation) adherence rate was 0.71 (+/-0.24), ranging from 0.02 to 0.97. One hundred nine of these patients (55.6%) took greater than 75% of the expected doses. Those with adherence of less than 50% of expected doses showed substantially increased dose taking immediately after the office visit and just before the return visit at 3 months (P = 0.03). The mean adherence rate estimates of the physician and patient self-report were 0.77 and 0.95, respectively. The agreement between the physician assessment and DA-recorded adherence rate showed poor correlation for individual cases (intraclass correlation coefficient, 0.09; 95% confidence interval, 0.00-0.19). CONCLUSIONS Nearly 45% of patients using an electronic monitoring device who knew they were being monitored and were provided free medication used their drops less than 75% of the time. Patients reported far higher medication use than their actual behavior. The ability of the physician to identify which persons are poorly adherent from their self-report or from other subjective clues is poor. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.

Lens Vault, Thickness, and Position in Chinese Subjects with Angle Closure

PURPOSE To investigate the association of lens parameters-specifically, lens vault (LV), lens thickness (LT), and lens position (LP)-with angle closure. DESIGN Prospective, comparative study. PARTICIPANTS One hundred two Chinese subjects with angle closure (consisting of primary angle closure, primary angle-closure glaucoma, and previous acute primary angle closure) attending a glaucoma clinic and 176 normal Chinese subjects with open angles and no evidence of glaucoma recruited from an ongoing population-based cross-sectional study. METHODS All participants underwent gonioscopy and anterior-segment optical coherence tomography (AS OCT; Carl Zeiss Meditec, Dublin, CA). Customized software was used to measure LV, defined as the perpendicular distance between the anterior pole of the crystalline lens and the horizontal line joining the 2 scleral spurs, on horizontal AS OCT scans. A-scan biometry (US-800; Nidek Co, Ltd, Tokyo, Japan) was used to measures LT and to calculate LP (defined as anterior chamber depth [ACD] +1/2 LT) and relative LP (RLP; defined as LP/axial length [AL]). MAIN OUTCOME MEASURES Lens parameters and angle closure. RESULTS Significant differences between angle-closure and normal eyes were found for LV (901±265 vs. 316±272 μm; P<0.001), LT (4.20±0.92 vs. 3.90±0.73 mm; P = 0.01), LT-to-AL ratio (0.18±0.04 vs. 0.16±0.03; P<0.001), ACD (2.66±0.37 vs. 2.95±0.37 mm; P<0.001), and AL (22.86±0.93 vs. 23.92±1.37 mm; P<0.001), but no significant differences were found for LP (4.76±0.51 vs. 4.90±0.54 mm; P = 0.34) or RLP (0.21±0.02 vs. 0.20±0.02; P = 0.14). After adjusting for age, gender, ACD, LT, and RLP, increased LV was associated significantly with angle closure (odds ratio [OR], 48.1; 95% confidence interval [CI], 12.8-181.3, comparing lowest to highest quartile), but no association was found for LT (OR, 1.78; 95% CI, 0.76-4.16), LP (OR, 1.94; 95% CI, 0.59-6.31), or RLP (OR, 2.08; 95% CI, 0.66-6.57). There was low correlation between LV and LT (Pearsons correlation coefficient [PCC], 0.17), between LV and RLP (PCC, 0.08), or between LV and LP (PCC, 0.2). CONCLUSIONS Eyes with angle closure have thicker lenses with greater LV compared with normal eyes. The LV, which represents the anterior portion of the lens, is a novel parameter independently associated with angle closure after adjusting for age, gender, ACD, and LT.