Aimee T. Broman

THE NUMBER OF PEOPLE WITH GLAUCOMA WORLDWIDE IN 2010 AND 2020

Aim: To estimate the number of people with open angle (OAG) and angle closure glaucoma (ACG) in 2010 and 2020. Methods: A review of published data with use of prevalence models. Data from population based studies of age specific prevalence of OAG and ACG that satisfied standard definitions were used to construct prevalence models for OAG and ACG by age, sex, and ethnicity, weighting data proportional to sample size of each study. Models were combined with UN world population projections for 2010 and 2020 to derive the estimated number with glaucoma. Results: There will be 60.5 million people with OAG and ACG in 2010, increasing to 79.6 million by 2020, and of these, 74% will have OAG. Women will comprise 55% of OAG, 70% of ACG, and 59% of all glaucoma in 2010. Asians will represent 47% of those with glaucoma and 87% of those with ACG. Bilateral blindness will be present in 4.5 million people with OAG and 3.9 million people with ACG in 2010, rising to 5.9 and 5.3 million people in 2020, respectively. Conclusions: Glaucoma is the second leading cause of blindness worldwide, disproportionately affecting women and Asians.

Influence of corneal structure, corneal responsiveness, and other ocular parameters on tonometric measurement of intraocular pressure

PurposeTo estimate the relationships between ocular parameters and tonometrically measured intraocular pressure (IOP), to determine the influence of ocular parameters on different instrument measurements of IOP, and to evaluate the association of ocular parameters with a parameter called hysteresis. MethodsPatients presenting at a glaucoma clinic were recruited for this study. Subjects underwent IOP measurement with the Goldmann applanation tonometer (GAT), the TonoPen, and the Reichert Ocular Response Analyzer (ORA), and also measurements of central corneal thickness (CCT), axial length, corneal curvature, corneal astigmatism, central visual acuity, and refractive error. Chart information was reviewed to determine glaucoma treatment history. The ORA instrument provided a measurement called corneal hysteresis. The association between measured IOP and the other ocular characteristics was estimated using generalized estimating equations. ResultsAmong 230 patients, IOP measurements from the TonoPen read lowest, and ORA read highest, and GAT measurements were closest to the mean IOP of the 3 instruments. In a multiple regression model adjusting for age, sex, race, and other ocular characteristics, a 10 μm increase in CCT was associated with an increase of 0.79 mm Hg measured IOP in untreated eyes (P<0.0001). Of the 3 tonometers, GAT was the least affected by CCT (0.66 mm Hg/10 μm, P<0.0001). Hysteresis was significantly correlated with CCT with a modest correlation coefficient (r=0.20, P<0.0007). ConclusionsAmong parameters related to measured IOP, features in addition to CCT, such as hysteresis and corneal curvature, may also be important. Tonometric instruments seem to be affected differently by various physiologic characteristics.

Association of visual field loss and mobility performance in older adults: Salisbury Eye Evaluation Study.

Purpose. To determine the association between visual field loss and orientation and mobility (O&M) performance in a population-based sample of older adults and to identify the specific regions of the visual field that are most strongly associated with O&M performance. Methods. A population-based sample of 1504 persons between the ages of 72 to 92 was enrolled in the third round of Salisbury Eye Evaluation. Monocular visual fields (60° radius) were tested with the 81-point, single intensity (24 dB) screening test strategy on the Humphrey Field Analyzer. Binocular visual fields were estimated from a combination of the monocular fields. The number of points missed was calculated for the overall visual field and for 3 non-overlapping regions: central (≤ 20° radius), upper- and lower-peripheral visual fields. Orientation and mobility performance was evaluated by walking speed, number of bumps, and number of orientation errors on a circuitous, 32.8-m course seeded with obstacles. Log-linear regressions and linear regressions, adjusting for age, gender, body mass, height, cognitive and general health status, were performed. Results. Loss in the overall visual field was associated with an increase in the number of bumps and decrease in walking speed. Visual field loss was not associated with the number of orientation errors. Out of the three visual field sub-regions that we tested, in terms of percentage of loss, the central and lower peripheral regions showed comparable decrements in walking speed and the central region was most strongly associated with number of bumps. Conclusions. The loss in visual field, which occurs with aging, is associated with a decline in mobility performance. Walking speed decreases, and the number of bumps into obstacles increases, with decreases in the visual field. The number of orientation errors is not associated with the loss in visual field that occurs with aging.

Causes of blindness and visual impairment in a population-based sample of U.S. Hispanics

OBJECTIVE To describe the causes of blindness and visual impairment in a population-based sample of Hispanics. DESIGN A cross-sectional study. PARTICIPANTS A random sample of 4774 Hispanic residents of Santa Cruz and Pima Counties in Southern Arizona aged 40 years and older who participated in Proyecto VER (Vision Evaluation and Research). TESTING Subjects were interviewed and underwent a thorough ophthalmic examination. Presenting and best-corrected visual acuity was determined using the Early Treatment of Diabetic Retinopathy Study protocol, followed by a standardized ophthalmic examination to determine the causes of visual loss. Anterior and posterior segment specialists in ophthalmology confirmed the causes. MAIN OUTCOME MEASURES Causes of visual loss (best-corrected acuity worse than 20/40). RESULTS The response rate of eligible participants was more than 70%. Best-corrected acuity in the better seeing eye worse than 20/40 increased from 0.3% in those aged 40 to 49 to 5.6% in those aged 65 and older. The leading cause was cataract, accounting for 42% of all visual loss, followed by age-related macular degeneration (15%), and diabetic retinopathy (13%). Among 14 people who were bilaterally blind, open-angle glaucoma was the leading cause. Women had higher age-adjusted prevalence of severe cataract compared with men and were more likely to be visually impaired from cataract, diabetic retinopathy, and open-angle glaucoma, although gender differences were not statistically significant. CONCLUSIONS Causes of visual impairment differ from those reported in Caucasian populations, with open-angle glaucoma being the leading cause of blindness. Further work on gender-based obstacles to eye care in the Hispanic community may be warranted.

Age, gender, biometry, refractive error, and the anterior chamber angle among Alaskan Eskimos

BACKGROUND The prevalence of angle-closure glaucoma (ACG) is greater for Eskimos/Inuit than it is for any other ethnic group in the world. Although it has been suggested that this prevalence may be due to a population tendency toward shallower anterior chamber angles, available evidence for other populations such as Chinese with high rates of ACG has not consistently demonstrated such a tendency. METHODS A reticule, slit-lamp, and standard Goldmann one-mirror goniolens were used to make measurements in the anterior chamber (AC) angle according to a previously reported protocol for biometric gonioscopy (BG) (Ophthalmology 1999;106:2161-7). Measurements were made in all four quadrants of one eye among 133 phakic Alaskan Eskimos aged 40 years and older. Automatic refraction, dilated examination of the anterior segment and optic nerve, and A-scan measurements of AC depth, lens thickness, and axial length were also carried out for all subjects. RESULTS Both central and peripheral AC measurements for the Eskimo subjects were significantly lower than those previously reported by us for Chinese, blacks, and whites under the identical protocol. Eskimos also seemed to have somewhat more hyperopia. There were no differences in biometric measurements between men and women in this Eskimo population. Angle measurements by BG seemed to decline more rapidly over life among Eskimos and Chinese than blacks or whites. Although there was a significant apparent decrease in AC depth, increase in lens thickness, and increase in hyperopia with age among Eskimos, all of these trends seemed to reverse in the seventh decade and beyond. CONCLUSIONS Eskimos do seem to have shallower ACs than do other racial groups. Measurements of the AC angle seem to decline more rapidly over life among Eskimos than among blacks or whites, a phenomenon also observed by us among Chinese, another group with high ACG prevalence. This apparent more rapid decline may be due to a cohort effect with higher prevalence of myopia and resulting wider angles among younger Eskimos and Chinese.

Risk factors for type ii diabetes and diabetic retinopathy in a mexican-american population: proyecto ver

PURPOSE Risk factors for type II diabetes and diabetic retinopathy were determined in a population-based study of Mexican-Americans. DESIGN Proyecto VER (Vision, Evaluation, and Research) is a cross-sectional study in a random sample of the self-described Hispanic populations in Tucson and Nogales, Arizona, age 40 and older. METHODS Of 6,659 eligible subjects, 4,774 (72%) participated in the home questionnaire and clinic visit. Diabetes was defined as self-report of a physician diagnosis or hemoglobin A(1c) value of > or = 7.0%. Only type II diabetes was included. Diabetic retinopathy was assessed on stereo fundus photographs of all persons with diabetes. Questions were asked about demographic, personal, socioeconomic, and diabetes related variables. RESULTS 1023 (21.4%) of the sample had type II diabetes, and 68% were in the low-income group (annual income less than

Low Luminance Visual Dysfunction as a Predictor of Subsequent Visual Acuity Loss from Geographic Atrophy in Age-Related Macular Degeneration

20,000). Diabetes was associated with Native-American ancestry, higher acculturation, low income, less education, and increasing body mass index after age and gender adjustment. Persons with previously undiscovered diabetes were more likely to have no regular source of care, no insurance, and currently smoke compared with persons with known diabetes. Only low income was related to proliferative retinopathy, once adjusted for other factors (odds ratio [OR] = 3.93, 95%, confidence limitations [CL] = 1.31-11.80). CONCLUSIONS Several socioeconomic and other factors were associated with diabetes, but few were related to diabetic retinopathy. Persons in the low-income group appeared to be at greater risk of diabetes and the ocular complications of diabetes compared with those with more income. Further longitudinal studies in this population are needed to confirm the associations.

Age and sex variation in angle findings among normal Chinese subjects: a comparison of UBM, Scheimpflug, and gonioscopic assessment of the anterior chamber angle.

OBJECTIVE To show that low luminance visual dysfunction is predictive of subsequent visual acuity (VA) loss in eyes with geographic atrophy (GA) resulting from age-related macular degeneration (AMD). DESIGN Cohort study examining the prospective natural history study of GA from 1992 through 2000 at the Wilmer Eye Institute. PARTICIPANTS Ninety-one participants with GA resulting from AMD without choroidal neovascularization in at least 1 eye who completed a 2-year study examination. METHODS Annual examinations included measurement of best-corrected VA, low luminance VA, Pelli-Robson contrast sensitivity, reading speed, examination, and fundus photography. The total GA area was quantified, as was the GA within a 10.2-mm(2) circle centered on the fovea. MAIN OUTCOME MEASURES Visual acuity loss at 2 years and risk factors for visual loss. RESULTS Participants with baseline VA of 20/50 or more had a 40% 2-year rate of VA loss of 3 lines or more, compared with 13% for the participants with worse baseline acuities. The baseline low-luminance deficit (LLD) in VA was a strong predictor of subsequent VA loss for all levels of baseline VA. Within the good baseline VA group, the relative risk (RR) of 3-line loss for the worse LLD group compared with the better LLD group was 2.88 (95% confidence interval [CI], 1.13-7.35). The LLD is a stable and reproducible measure. Other significant visual function predictors of subsequent VA loss in eyes with good baseline VA included foveal dark-adapted sensitivity (RR, 4.20; 95% CI, 1.39-12.71) and reduced reading rate (RR, 2.43; 95% CI, 1.11-5.31). The rate of VA loss within the good acuity group was higher when the GA included 25% to 75% of the central 10.2 mm(2) than in eyes with GA including less than 25% or more than 75% of the central 10.2 mm(2). The following were not significant predictors of subsequent VA loss among these participants: age, gender, fellow eye diagnosis, fellow eye VA, baseline GA area, and GA enlargement rate. CONCLUSIONS Visual function measures can predict the risk of future VA loss in subjects with GA and good baseline VA. They may allow identification of the highest risk group for VA loss, enabling more efficient design of clinical trials. They also may be appropriate surrogate measures of foveal health in short-term treatment trials.

Effectiveness of Careful Bedside Examination in Assessment, Diagnosis, and Prognosis of Vestibular Neuritis

BackgroundLimited data are published on the ultrasound biomicroscope (UBM) findings of the anterior chamber angle. This work provides a population-based assessment of angle findings and compares 3 modalities for assessing angle dimensions. MethodsA sample of 268 persons who had participated in a population-based study of glaucoma prevalence in Singapore were reexamined by UBM (nasal, temporal, and inferior angles only), Scheimpflug photography of angle width, and gonioscopy. Angle findings were compared, and age and sex influences evaluated. ResultsThe temporal angle was the widest of the 3 angles imaged with the UBM, and the inferior angle was the narrowest (nearly 20% more narrow than the temporal angle, P<0.005). Women were found to have narrower angles than men and older persons had more narrow angles. Scheimpflug photography did not provide enough detail of the angle to increase our understanding of angle anatomy. ConclusionsThe data reported support earlier findings that the anterior chamber angle is narrower in older individuals and women. Methods of assessing the angle may themselves influence the appearance of the angle. Limited agreement exists between the angle quantification methods studied. An ideal method of angle assessment would not contact the eye and would not require light be directed at the eye.

A randomized trial of visual impairment interventions for nursing home residents: Study design, baseline characteristics and visual loss

OBJECTIVE To determine whether the use of 4 bedside tests (head-impulse, head-heave, head-shake, and vibration tests) can be as effective as the caloric test, a widely accepted standard, in the diagnosis and prediction of the time to recovery from vestibular neuritis. DESIGN Inception cohort (1-year follow-up), criterion standard study. SETTING Primary referral center. PATIENTS All patients had acute vertigo, and those having a diagnosis of vestibular neuritis were eligible for inclusion in the study. Sixty-eight patients (43 men and 25 women; mean age, 54.9 years) met this criterion, and 53 of them (77.9%) completed the study. MAIN OUTCOME MEASURES Spontaneous head-shaking and vibration-induced nystagmus elicited with a battery-powered device were tested wearing Frenzel goggles. The head-impulse and head-heave tests were performed manually. Caloric irrigation was administered with hot, cold, and ice water. RESULTS At baseline, more than half of the patients exhibited positive signs with all 4 tests and all had caloric paralysis or paresis. Signs with the head-impulse and head-heave tests correlated highly (odds ratio, 24.9; P < .001), as did those with the head-shake and vibration tests (odds ratio, 22.8; P < .001). Patients with a positive sign with the head-impulse or vibration test were 70% less likely to recover than were those with a negative sign. Head-impulse (hazard ratio, 0.08; P = .002) and head-shake (hazard ratio, 0.23; P = .01) test results were associated with the outcome of the caloric test. CONCLUSION Careful bedside examination of patients with vestibular neuritis has both diagnostic value in the short term and prognostic value in the long term.