Pradeep Y. Ramulu

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.

Iris cross-sectional area decreases with pupil dilation and its dynamic behavior is a risk factor in angle closure.

PurposeTo estimate the change in iris cross-sectional (CS) area with pupil dilation using anterior segment optical coherence tomography comparing eyes with angle closure (AC) to open angle glaucoma (OAG). MethodsSixty-five patients from the Wilmer Glaucoma service, 36 with definite or suspected OAG and 29 with definite or suspected AC, underwent anterior segment optical coherence tomography imaging under 3 conditions (pupil constriction to light, physiologic dilation in the dark, and after pharmacologic dilation). The nasal and temporal iris CS areas were measured with custom software, 3 times in each of 4 meridians. The principal outcome variables were iris CS area and change in iris CS area/mm pupil diameter change. The relation of these parameters to potential variables that would influence iris area was estimated by multivariate regression. ResultsCS area was smaller in eyes with larger pupil diameter, those that had undergone trabeculectomy, and those of European-derived persons (P<0.05 for all in a univariate analysis). In a multivariate model with CS area as the dependent variable, larger pupil diameter (with a 0.19 mm2 decrease in CS area for each 1 mm of pupil enlargement, P=0.0002), and trabeculectomy remained significant factors. In a second multivariate model, AC irides had less change in CS area/mm pupil enlargement than OAG or OAG suspects (P=0.01). Change in iris CS area was essentially complete in 5 seconds (n=10 eyes). ConclusionsThe iris loses nearly half its volume from a pupil diameter of 3 to 7 mm, probably by eliminating extracellular fluid. Smaller iris CS area change with physiologic pupil dilation is a potential risk factor for AC. Dynamic iris CS area change deserves testing as a prospective indicator of AC.

Driving Cessation and Driving Limitation in Glaucoma: The Salisbury Eye Evaluation Project

OBJECTIVE To determine if glaucoma is associated with driving limitation or cessation. DESIGN Cross-sectional analysis within a longitudinal, population-based cohort study. PARTICIPANTS AND CONTROLS One thousand one hundred thirty-five ever-drivers between 73 and 93, including 70 subjects with unilateral and 68 subjects with bilateral glaucoma. METHODS All subjects reported their driving habits during each of 4 study rounds. During the fourth and final study round, subjects were assessed systematically for the presence of glaucoma. MAIN OUTCOME MEASURES Self-reported driving cessation or driving limitation, including cessation of night driving, driving fewer than 3000 miles annually, or cessation of driving in unfamiliar areas. RESULTS Fifteen percent of subjects without glaucoma no longer were driving at the end of the cohort study, compared with 21% of unilateral glaucoma subjects (P = 0.2) and 41% of bilateral glaucoma subjects (P<0.001). Multivariate regression analysis showed that bilateral (odds ratio [OR], 2.6; P = 0.002), but not unilateral (OR, 1.5; P = 0.3), glaucoma subjects were more likely no longer to be driving when compared with subjects without glaucoma. The odds that bilateral glaucoma subjects no longer were driving doubled for every 5 dB of visual field (VF) worsening in the better eye (P<0.001). Driving cessation within the previous 2 years was analyzed using separate multiple regression models, and both bilateral (OR, 3.6; P = 0.004) and unilateral (OR, 2.4; P = 0.06) glaucoma subjects were more likely to stop driving over this period than subjects without glaucoma. Driving cessation associated with bilateral glaucoma was present in 0.82% of the population, or 1 in every 122 individuals. Greater numbers of driving limitations were not more likely among subjects with glaucoma than subjects without glaucoma. However, bilateral glaucoma subjects did attribute more driving limitations to difficulties with their vision than subjects without glaucoma (OR, 2.2; P = 0.02). CONCLUSIONS Bilateral, and possibly unilateral, glaucoma is associated with significantly higher rates of driving cessation among the elderly. The substantial difference in driving patterns seen with different degrees of better-eye VF damage suggests that minimizing VF loss in the better-seeing eye is associated with better functional outcomes.

Glaucoma and Reading Speed: The Salisbury Eye Evaluation Project

OBJECTIVE To determine if, and at what point, glaucoma affects spoken reading speed. METHODS Data were collected from the Salisbury Eye Evaluation, a population-based evaluation of visual function and disability in the elderly population. Nonscrolling text was displayed on a screen and the rate words were read aloud was measured. Subjects reading slower than 90 words/min were defined as having impairment. Glaucoma status was determined using optic disc appearance and visual field testing. RESULTS One thousand one hundred fifty-four subjects completed evaluations of spoken reading speed and glaucoma status. Univariate analysis demonstrated reading impairment in 16.0% of subjects without glaucoma, 21.1% of subjects with unilateral glaucoma (P = .25), and 28.4% of subjects with bilateral glaucoma (P = .006). Multivariable regression demonstrated nonsignificant increases in the odds of reading impairment for subjects with unilateral (odds ratio, [OR], 1.13; P = .69) and bilateral glaucoma (OR, 1.25; P = .43), though subjects with bilateral glaucoma in the highest quartile of better-eye visual field loss read slower (beta = -32 words/min; P = .01) and were more often reading impaired than controls without glaucoma (OR, 3.8; P = .04). Race, cognitive ability, education, and visual acuity were important predictors of reading impairment. CONCLUSIONS High rates of spoken reading impairment were found throughout this elderly sample. Glaucoma was associated with slower reading and increased reading impairment with advanced bilateral field loss.

Fear of Falling and Visual Field Loss from Glaucoma

OBJECTIVE To determine if visual field (VF) loss resulting from glaucoma is associated with greater fear of falling. DESIGN Prospective, observational study. PARTICIPANTS Fear of falling was compared between 83 glaucoma subjects with bilateral VF loss and 60 control subjects with good visual acuity and without significant VF loss recruited from patients followed up for suspicion of glaucoma. METHODS Participants completed the University of Illinois at Chicago Fear of Falling Questionnaire. The extent of fear of falling was assessed using Rasch analysis. MAIN OUTCOME MEASURES Subject ability to perform tasks without fear of falling was expressed in logits, with lower scores implying less ability and greater fear of falling. RESULTS Glaucoma subjects had greater VF loss than control subjects (median better-eye mean deviation [MD] of -8.0 decibels [dB] vs. +0.2 dB; P<0.001), but did not differ with regard to age, race, gender, employment status, the presence of other adults in the home, body mass index (BMI), grip strength, cognitive ability, mood, or comorbid illness (P ≥ 0.1 for all). In multivariate models, glaucoma subjects reported greater fear of falling as compared with controls (β = -1.20 logits; 95% confidence interval [CI], -1.87 to -0.53; P = 0.001), and fear of falling increased with greater VF loss severity (β = -0.52 logits per 5-dB decrement in the better eye VF MD; 95% CI, -0.72 to -0.33; P<0.001). Other variables predicting greater fear of falling included female gender (β = -0.55 logits; 95% CI, -1.03 to -0.06; P = 0.03), higher BMI (β = -0.07 logits per 1-unit increase in BMI; 95% CI, -0.13 to -0.01; P = 0.02), living with another adult (β = -1.16 logits; 95% CI, -0.34 to -1.99 logits; P = 0.006), and greater comorbid illness (β = -0.53 logits/1 additional illness; 95% CI, -0.74 to -0.32; P<0.001). CONCLUSIONS Bilateral VF loss resulting from glaucoma is associated with greater fear of falling, with an impact that exceeds numerous other risk factors. Given the physical and psychological repercussions associated with fear of falling, significant quality-of-life improvements may be achievable in patients with VF loss by screening for, and developing interventions to minimize, fear of falling.

Use of Retinal Procedures in Medicare Beneficiaries From 1997 to 2007

OBJECTIVE To observe how the treatment of retinal conditions changed over the preceding decade. METHODS Medicare fee-for-service data claims filed between 1997 and 2007 were analyzed. RESULTS Fewer than 5000 intravitreal injections of a pharmacological agent were performed annually between 1997 and 2001. Thereafter, the annual number of intravitreal injections more than doubled every year through 2006, reaching a high of 812,413 in 2007. Photodynamic therapy procedures decreased 83% from a peak of 133,565 procedures in 2004 to 22,675 procedures in 2007, while laser treatment of choroidal lesions or neovascularization decreased 83% from a peak of 82,089 in 1999 to a minimum of 13,821 in 2007. Vitrectomies for primary retinal detachment (with or without scleral buckling) increased 72% over the study period from 11,212 in 1997 to 19,923 in 2007, while scleral buckles performed without vitrectomy decreased 69% from 8691 to 2660. Substantial volume increases were also observed for vitrectomy with retinal membrane stripping (90% increase from 29,426 in 1997 to 56,051 in 2007) or endolaser panretinal photocoagulation (86% increase from 10,319 in 1997 to 19,154 in 2007). Volumes of pneumatic retinopexy, laser prophylaxis for retinal detachment, laser treatment for retinal edema, and laser treatment for retinopathy all changed less than 25% from 1997 and 2007. CONCLUSIONS Marked changes in the use of several retinal procedures occurred between 1997 and 2007, particularly in the treatment of macular degeneration and retinal detachment. These changes point to greater acceptance and incorporation of vitrectomy and intravitreal injection as treatment modalities.

Use of Various Glaucoma Surgeries and Procedures in Medicare Beneficiaries from 1994 to 2012

PURPOSE Determine how procedural treatments for glaucoma have changed between 1994-2012. DESIGN Retrospective, observational analysis. PARTICIPANTS Medicare Part B beneficiaries. METHODS We analyzed Medicare fee-for-service paid claims data between 1994-2012 to determine the number of surgical/laser procedures performed for glaucoma in the Medicare population each year. MAIN OUTCOME MEASURES Number of glaucoma-related procedures performed. RESULTS Trabeculectomies in eyes without previous scarring decreased 52% from 54 224 in 1994 to 25 758 in 2003, and a further 52% to 12 279 in 2012. Trabeculectomies in eyes with scarring ranged from 9054 to 13 604 between 1994-2003, but then decreased 48% from 11 018 to 5728 between 2003-2012. Mini-shunts done via an external approach (including ExPRESS [Alcon Inc, Fort Worth, TX]) increased 116% from 2718 in 2009 to 5870 in 2012. The number of aqueous shunts to the extraocular reservoir increased 231% from 2356 in 1994 to 7788 in 2003, and a further 54% to 12 021 in 2012. Total cyclophotocoagulation procedures increased 253% from 2582 in 1994 to 9106 in 2003, and a further 54% to 13 996 in 2012. Transscleral cyclophotocoagulations decreased 45% from 5978 to 3268 between 2005-2012; over the same period, the number of endoscopic cyclophotocoagulations (ECPs) increased 99% from 5383 to 10 728. From 2001 to 2005, the number of trabeculoplasties more than doubled from 75 647 in 2001 to 176 476 in 2005, but since 2005 the number of trabeculoplasties decreased 19% to 142 682 in 2012. The number of laser iridotomies was fairly consistent between 1994-2012, increasing 9% over this period and ranging from 63 773 to 85 426. Canaloplasties increased 1407% from 161 in 2007 to 2426 in 2012. Between 1994-2012, despite a 9% increase in beneficiaries, the total number of glaucoma procedures and the number of glaucoma procedures other than laser procedures decreased 16% and 31%, respectively. CONCLUSIONS Despite the increase in beneficiaries, the number of glaucoma procedures performed decreased. Glaucoma procedures demonstrating a significant increase in use include canaloplasty, mini-shunts (external approach), aqueous shunt to extraocular reservoir, and ECP. Trabeculectomy use continued its long-term downward trend. The continued movement away from trabeculectomy and toward alternative intraocular pressure-lowering procedures highlights the need for well-designed clinical trials comparing these procedures.

Real-World Assessment of Physical Activity in Glaucoma Using an Accelerometer

OBJECTIVE To determine the association between glaucomatous visual field (VF) loss and the amount of physical activity and walking in normal life. DESIGN Prospective, observational study. PARTICIPANTS Glaucoma suspects without significant VF or visual acuity loss (controls) and glaucoma subjects with bilateral VF loss between 60 and 80 years of age. METHODS Participants wore an accelerometer over 7 days of normal activity. MAIN OUTCOME MEASURES Daily minutes of moderate or vigorous physical activity (MVPA) was the primary measure. Steps per day was a secondary measure. RESULTS Fifty-eight controls and 83 glaucoma subjects provided sufficient study days for analysis. Control and glaucoma subjects were similar in age, race, gender, employment status, cognitive ability, and comorbid illness (P>0.1 for all). Better-eye VF mean deviation (MD) averaged 0.0 decibels (dB) in controls and -11.1 dB in glaucoma subjects. The median control subject engaged in 16.1 minutes of MVPA daily and walked 5891 steps/day, as compared with 12.9 minutes of MVPA daily (P = 0.25) and 5004 steps/day (P = 0.05) for the median glaucoma subject. In multivariate models, glaucoma was associated with 21% less MVPA (95% confidence interval [CI], -53% to 32%; P = 0.37) and 12% fewer steps per day (95% CI, -22% to 9%; P = 0.21) than controls, although differences were not statistically significant. There was a significant dose response relating VF loss to decreased activity, with each 5 dB decrement in the better-eye VF associated with 17% less MVPA (95% CI, -30% to -2%; P = 0.03) and 10% fewer steps per day (95% CI, -16% to -5%; P = 0.001). Glaucoma subjects in the most severe tertile of VF damage (better-eye VF MD worse than -13.5 dB) engaged in 66% less MVPA than controls (95% CI, -82% to -37%; P = 0.001) and took 31% fewer steps per day (95% CI, -44% to -15%; P = 0.001). Other significant predictors of decreased physical activity included older age, comorbid illness, depressive symptoms, and higher body mass index. CONCLUSIONS Overall, no significant difference in physical activity was found between individuals with and without glaucoma, although substantial reductions in physical activity and walking were noted with greater levels of VF loss. Further study is needed to characterize better the relationship between glaucoma and physical activity. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Association of Vision Loss in Glaucoma and Age-Related Macular Degeneration with IADL Disability

PURPOSE To determine if glaucoma and/or age-related macular degeneration (AMD) are associated with disability in instrumental activities of daily living (IADLs). METHODS Glaucoma subjects (n = 84) with bilateral visual field (VF) loss and AMD subjects (n = 47) with bilateral or severe unilateral visual acuity (VA) loss were compared with 60 subjects with normal vision (controls). Subjects completed a standard IADL disability questionnaire, with disability defined as an inability to perform one or more IADLs unassisted. RESULTS Disability in one or more IADLs was present in 18.3% of controls as compared with 25.0% of glaucoma subjects (P = 0.34) and 44.7% of AMD subjects (P = 0.003). The specific IADL disabilities occurring more frequently in both AMD and glaucoma subjects were preparing meals, grocery shopping, and out-of-home travelling (P < 0.05 for both). In multivariate logistic regression models run adjusting for age, sex, mental status, comorbidity, and years of education, AMD (odds ratio [OR] = 3.4, P = 0.02) but not glaucoma (OR = 1.4, P = 0.45) was associated with IADL disability. However, among glaucoma and control patients, the odds of IADL disability increased 1.6-fold with every 5 dB of VF loss in the better-seeing eye (P = 0.001). Additionally, severe glaucoma subjects (better-eye MD worse than -13.5 dB) had higher odds of IADL disability (OR = 4.2, P = 0.02). Among AMD and control subjects, every Early Treatment of Diabetic Retinopathy Study line of worse acuity was associated with a greater likelihood of IADL disability (OR = 1.3). CONCLUSIONS VA loss in AMD and severe VF loss in glaucoma are associated with self-reported difficulties with IADLs. These limitations become more likely with increasing magnitude of VA or VF loss.

Difficulty with Out-Loud and Silent Reading in Glaucoma

PURPOSE We evaluated the impact of glaucoma on out-loud and silent reading. METHODS. Glaucoma patients with bilateral visual field (VF) loss and normally-sighted controls had the following parameters measured: speed reading an International Reading Speed Text (IReST) passage out loud, maximum out-loud MNRead chart reading speed, sustained (30 minutes) silent reading speed, and change in reading speed during sustained silent reading. RESULTS Glaucoma subjects read slower than controls on the IReST (147 vs. 163 words per minute [wpm], P < 0.001), MNRead (172 vs. 186 wpm, P < 0.001), and sustained silent (179 vs. 218 wpm, P < 0.001) tests. In multivariable analyses adjusting for age, race, sex, education, employment, and cognition, IReST and MNRead reading speeds were 12 wpm (6%-7%) slower among glaucoma subjects compared to controls (P < 0.01 for both), while sustained silent reading speed was 16% slower (95% confidence interval [CI] = -24 to -6%, P = 0.002). Each 5 decibel (dB) decrement in better-eye VF mean deviation was associated with 6 wpm slower IReST reading (95% CI = -9 to -3%, P < 0.001), 5 wpm slower MNRead reading (95% CI = -7 to -2%, P < 0.001), and 9% slower sustained silent reading (95% CI = -13 to -6%, P < 0.001). A reading speed decline of 0.5 wpm/min or more over the sustained silent reading period was more common among glaucoma subjects than controls (odds ratio [OR] = 2.2, 95% CI = 1.0-4.9, P < 0.05). CONCLUSIONS Reading speed is slower among glaucoma patients with bilateral VF loss, with the greatest impact present during sustained silent reading. Persons with glaucoma fatigue during silent reading, resulting in slower reading over time.