Prevalence of Primary Open-angle Glaucoma in an Urban South Indian Population and Comparison with a Rural Population

Older Drivers and Glaucoma in India: Driving Habits and Crash Risks

PRéCIS:: In India, older drivers with glaucoma show greater driving difficulty but are not involved in higher number of on-road accidents. To achieve balance between safety aspects and independence for drivers with glaucoma is important.

PURPOSE

The purpose of this study was to analyze driving habits of patients with glaucoma and to compare their driving behavior, driving difficulties, and accident rates with nonglaucoma controls.

PATIENTS

Patients with glaucoma aged older than 40 years were recruited. Subjects with best-corrected visual acuity ≤6/24 in the better-seeing eye and those having primary eye disorder other than glaucoma were excluded. Age-matched nonglaucoma controls were recruited. Subjects with clinically significant cataract and/or with best-corrected visual acuity ≤6/24 in both eyes were excluded. All cases and controls were legally licensed to drive.

MATERIALS AND METHODS

In this study, Driving Habits Questionnaire was used. Collected data were statistically analyzed using SAS, version 9.2 (GLM procedure), and IBM SPSS, version 22. P-values <0.05 were considered statistically significant.

RESULTS

All controls and 84% (n=84/100) of cases were current drivers. Among them, 16% (n=16/100) cases had stopped driving, of which 31.25% (n=5/16) had stopped because of self-reported ocular causes. Cases drove lesser number of days per week (P=0.001) and had more driving dependence on other drivers (44%, n=37/84) compared with controls. Glaucoma was significantly associated with driving difficulty in the rain, in rush-hour traffic, and at night. Comparing driving difficulty scores and visual field index within glaucoma group showed statistical significance [F(1,82)=22.12, P<0.001]. Composite scores of driving difficulty (P<0.001) and driving space (P=0.003) between the 2 groups showed strong statistical significance. Controls had higher number of self-reported accidents (P<0.001).

CONCLUSIONS

Patients with glaucoma show greater driving difficulty, self-regulate their driving behavior, and restrict their driving. Older patients with glaucoma in India are not involved in higher rates of on-road crash risks compared with nonglaucoma drivers.

Glaucoma blindness-A rapidly emerging non-communicable ocular disease in India: Addressing the issue with advocacy

Glaucoma, a leading cause of irreversible blindness, can be prevented or stabilized the progression if identified early and managed it appropriately. In India, around 12 million people suffer from glaucoma, and 1.5 million are blind due to it, so making the third most common cause of blindness. More than 75% of glaucoma are undiagnosed, which perhaps represent the submerged portion of the iceberg phenomenon of the traditional disease explanations. Though glaucoma per se does not lead to mortality, glaucoma blindness is categorized as a severe form of disability (category VI) out of seven World Health Organization (WHO) classification on the global burden of diseases. Indeed, there is a large gap between the prevailing burden of glaucoma and service being delivered about its prevention compared to other leading causes of blindness in India. Considering the magnitude of the problem as well as the severity of disability, a strong and effective advocacy is an urgent call to deal glaucoma problem in the country. For a resource-limited country, where mass population based-screening programs are not feasible, alternative methods like facility-based opportunistic screening and referring the high-risk groups for early detection and treatment should be aimed. However, glaucoma should not be screened in isolation from other eye problems. In fact, screening of any potential blinding ocular problems, including glaucoma, should be a clear mandate under comprehensive eye program of the WHO to achieve Universal Eye Health Coverages. This paper highlights the strategy inclusive of advocacy to curtail the increasing burden of glaucoma blindness in India.

Spectrum of Eye Disease in Diabetes (SPEED) in India: A prospective facility-based study. Report # 4. Glaucoma in people with type 2 diabetes mellitus

Purpose

To estimate the proportion of people with type 2 diabetes mellitus (T2DM) and glaucoma in a facility-based cross-sectional observational study in India.

Methods

All people received a comprehensive eye examination. Glaucoma-specific examinations included applanation tonometry, optic disc and cup evaluation, and stereo biomicroscopy in all people; gonioscopy and visual field testing in glaucoma suspects. The International Society of Geographic and Epidemiologic Ophthalmology guidelines were used to diagnose and classify glaucoma.

Results

The study recruited 11,182 people (average age: 58.2 ± 10.6; range 39-96 years). Glaucoma was diagnosed in 4.9% (n = 547) people. About 76.8% (n = 420) of those with glaucoma had bilateral disease, and 98.7% (n = 540) were >40 years. Among people with bilateral disease, 94.5% (n = 397) had primary glaucoma - open angle in 59.3% (n = 228) and angle closure in 40.2% (n = 169). Diabetes duration was ≤10 years in 71.5% (n = 300) people. On linear regression, the following were associated with glaucoma: advancing age [compared with < 40 years age group; odds ratio [OR] in 50-60 year age group: 1.36 [95% confidence interval (CI): 1.01-1.8], P < 0.035); >60 years age group (OR: 2.05, 95% CI: 1.57-2.67; P < 0.001), and diabetic neuropathy (OR: 2.62, 95% CI: 1.35-5.10, P < 0.003). Glycemic control did not have significant association (P = 0.425).

Conclusion

Presence of glaucoma in people with T2DM in this cohort was similar to the general population prevalence studies in India. Glaucoma was invariably bilateral. A comprehensive eye examination in people age 40 years and older with diabetes and/or glaucoma is beneficial.

The Relationship Between Ambient Atmospheric Fine Particulate Matter (PM2.5) and Glaucoma in a Large Community Cohort

Purpose

Glaucoma is more common in urban populations than in others. Ninety percent of the world's population are exposed to air pollution above World Health Organization (WHO) recommended limits. Few studies have examined the association between air pollution and glaucoma.

Methods

Questionnaire data, ophthalmic measures, and ambient residential area air quality data for 111,370 UK Biobank participants were analyzed. Particulate matter with an aerodynamic diameter < 2.5 μm (PM2.5) was selected as the air quality exposure of interest. Eye measures included self-reported glaucoma, intraocular pressure (IOP), and average thickness of macular ganglion cell-inner plexiform layer (GCIPL) across nine Early Treatment Diabetic Retinopathy Study (ETDRS) retinal subfields as obtained from spectral-domain optical coherence tomography. We examined the associations of PM2.5 concentration with self-reported glaucoma, IOP, and GCIPL.

Results

Participants resident in areas with higher PM2.5 concentration were more likely to report a diagnosis of glaucoma (odds ratio = 1.06, 95% confidence interval [CI] = 1.01-1.12, per interquartile range [IQR] increase P = 0.02). Higher PM2.5 concentration was also associated with thinner GCIPL (β = -0.56 μm, 95% CI = -0.63 to -0.49, per IQR increase, P = 1.2 × 10-53). A dose-response relationship was observed between higher levels of PM2.5 and thinner GCIPL (P < 0.001). There was no clinically relevant relationship between PM2.5 concentration and IOP.

Conclusions

Greater exposure to PM2.5 is associated with both self-reported glaucoma and adverse structural characteristics of the disease. The absence of an association between PM2.5 and IOP suggests the relationship may occur through a non-pressure-dependent mechanism, possibly neurotoxic and/or vascular effects.

Heavy metal toxicity and the aetiology of glaucoma

Despite recent advances, our understanding of the aetiological mechanisms underlying glaucoma remains incomplete. Heavy metals toxicity has been linked to the development of neurodegenerative diseases and various ocular pathologies. Given the similarities in pathophysiology between glaucoma and some neurodegenerative disorders, it is plausible that heavy metal toxicity may play a role in the development of glaucoma. Heavy metal exposure may be occupational, or through water or dietary contamination. In this report, we review mechanisms for systemic and neurotoxicity for arsenic, cadmium, chromium, cobalt, lead, mercury, and manganese, and weigh the evidence for an association between glaucoma and the accumulation of heavy metals either in ocular tissues or in the central nervous system.

Latest Developments in Normal-Pressure Glaucoma: Diagnosis, Epidemiology, Genetics, Etiology, Causes and Mechanisms to Management

Normal-pressure glaucoma (NPG) is part of the spectrum of the open-angle glaucomas and morphologically characterized, as any glaucoma, by a loss of neuroretinal rim parallel to an enlargement and deepening of the optic cup, and development or enlargement of parapapillary beta zone. These morphological characteristics, in addition to the therapeutic benefit of lowering the intraocular pressure (IOP), make NPG differ from vascular-induced optic neuropathy. Based on the anatomy of the optic nerve as a cerebral fascicle, the physiological counter-pressure against the IOP is the orbital cerebrospinal fluid pressure (CSFP), with both pressures forming the trans-lamina cribrosa pressure difference (TLCPD). In contrast to the IOP, the TLCPD is the true pressure exerting force on the optic nerve fibers when passing through the lamina cribrosa. As a theoretical notion, an abnormally high TLCPD due to a low CSFP, in association with a low arterial blood pressure, could therefore be involved in the pathogenesis of NPG. It fits with the finding that the reduction of the IOP (and thus indirectly of the TLCPD) is (the only proven) procedure for NPG therapy. This review additionally highlights the genetic background, diagnostic methods, and therapeutic modalities of NPG.

Renewal of driving license in India and glaucoma: A study of prevalent practice and its lacunae

Purpose

Glaucoma affects different aspects of vision including visual field. This prospective observational study aims to collect details of driving license (DL) renewal procedure (in an urban metro in India) among patients with diagnosed glaucoma and the method of reporting of vision-related requirements during renewal.

Methods

One-hundred patients with diagnosed glaucoma above 40 years, having valid DL (with at least one renewal cycle), were included. Patients with other ocular comorbidities were excluded. Driving Habits Questionnaire and a questionnaire about license renewal were administered. Driving eligibility was compared to international guidelines.

Results

Study population included patients with 69% early, 29% moderate, and 2% advanced glaucoma. Sixteen percent of patients had stopped driving. Legal license renewal procedure was bypassed by 45%. Form-1 was not submitted by 43% and 49% did not submit Form-1A at the time of renewal. Only 7.01% mentioned about glaucoma in the self-declaration form. None were asked about their visual field during renewal. Among 61 patients who submitted a medical certificate, the undersigning doctor was an ophthalmologist in only six patients. Thirty percent patients with valid Indian DL would not have satisfied International College of Ophthalmologists guidelines. Driving difficulties were experienced by 44%, more so in advanced glaucoma (F (1, 82) = 22.12, P < 0.001).

Conclusion

Vision-related testing at the time of renewal of DL is inadequate in India. Chronic eye diseases such as glaucoma are commonly not self-declared or detected at pre-renewal testing. Clear-cut guidelines about visual requirements and implementation are required to prevent road traffic events because of vision-related errors.

Quantification of RAPD by an automated pupillometer in asymmetric glaucoma and its correlation with manual pupillary assessment

Purpose:

The relative afferent pupillary defect (RAPD) is an important sign of asymmetrical retinal ganglion cell damage. The purpose of this study was to quantify RAPD by a pupillometer (RAPiDo, Neuroptics) and assess its correlation with asymmetric glaucoma and manual pupillary assessment.

Methods:

A total of 173 subjects were enrolled in the study and categorized into glaucoma, n = 130, and control, n = 43. Subjects were all recruited in the Glaucoma Clinic of the Aravind Eye Hospital in Madurai during their follow-up. They were 18 years and older, with best corrected visual acuity of 6/36 or better. Exclusion criteria included all retinal pathologies, optic atrophies, ocular injuries, severe uveitis, cloudy corneas, dense cataracts, or use of mydriatics or miotic drugs. RAPD was assessed in all subjects using an automated pupillometer and the results were compared with the swinging flash light test conducted on the same subjects by an experienced ophthalmologist. We looked at the correlation between RAPD and the intereye difference in cup-to-disc ratio (CDR), mean deviation (MD) of visual field testing, and retinal nerve fiber layer (RNFL) thickness. Sensitivity and specificity were assessed by area under the receiver operator characteristic (AUROC) analysis.

Results:

Glaucoma patients had significant RAPD (0.55 ± 0.05 log units) when compared with the controls (0.25 ± 0.05 log units), P < 0.001. Significant intereye differences in CDR, MD, and RNFL between glaucoma and control (P < 0.001) were seen. There was a good correlation between the magnitude and sign of RAPD and these intereye differences in CDR (r = 0.52, P < 0.001), MD (r = 0.44, P < 0.001) and RNFL thickness (r = 0.59, P < 0.001). When compared with the experienced ophthalmologist, AUROC was 0.94, with 89% sensitivity and 91.7% specificity.

Conclusion:

The good correlation between the magnitude of RAPD, as measured by the automated pupillometer, and intereye differences in MD, CDR, and RNFL thickness in glaucomatous, and the good sensitivity and specificity when compared with the experienced ophthalmologist, suggest that pupillometry may be useful as a screening tool to assess asymmetric glaucoma.

Heterogeneity in arterial hypertension and ocular perfusion pressure definitions: Towards a consensus on blood pressure-related parameters for glaucoma studies

PURPOSE

Glaucoma studies have long taken into account the blood pressure (BP) status of patients. This study summarizes and evaluates the impact of the different criteria that have been used for BP-related variables in glaucoma research.

METHODS

Studies included in two meta-analyses that reviewed the role of BP in glaucoma were analyzed. Additional studies published after the search periods of the meta-analyses were also included. Criteria for the definition of arterial hypertension and other BP-related variables, such as mean arterial pressure (MAP) and mean ocular perfusion pressure (MOPP), were retrieved.

RESULTS

Sixty-four studies were evaluated. One-third used 140 mmHg as a systolic BP cut-off to define hypertension, 20% used 160 mmHg and the remaining half used various other criteria. Less than 20% of studies reported MAP and/or MOPP. While eight of the ten studies reporting MAP used a correct formula that only happened for five of the eleven studies reporting MOPP. Using as an example average blood pressure values, incorrectly used formulas could have led to an overestimation of more than 100% of the expected values.

CONCLUSION

Considerable heterogeneity exists in BP-related variables in glaucoma research and different definitions can lead to large disparities. Glaucoma research would benefit from a consensus regarding blood pressure parameters.

Cost-effectiveness of glaucoma screening in cataract camps versus opportunistic and passive screening in urban India: A study protocol

India has an estimated 12 million people affected with glaucoma; however, no organised screening programme exists. Cases are usually detected opportunistically. This study documents the protocol for detecting glaucoma in suspects in cataract camps conducted by Shroff Charity Eye Hospital in North India. We report a cost-effectiveness alongside prospective study design of patients attending cataract camps where glaucoma screening will be integrated. The eligible population for glaucoma screening is non-cataract patients. Patients will undergo glaucoma screening by a trained optometrist using a pre-determined glaucoma screening algorithm. Specific diagnostic cut-off points will be used to identify glaucoma suspects. Suspected patients will be referred to the main hospital for confirmatory diagnosis and treatment. This group will be compared to a cohort of patients arriving from cataract camps conducted by the institute in similar areas and undergoing examination in the hospital. The third arm of the study includes patients arriving directly to the hospital for the first time. Cost data will be captured from both the screening components of cataract-only and glaucoma screening-integrated camps for screening invitation and screening costs. For all three arms, examination and treatment costs will be captured using bottom-up costing methods at the hospital. Detection rates will be calculated by dividing the number of new cases identified during the study by total number of cases examined. Median, average and range of costs across the three arms will be calculated for cost comparisons. Finally, cost-effectiveness analysis will be conducted comparing cost per case detected across the three arms from a quasi-societal perspective with a time horizon of 1 year . Ethics approval for the study has been obtained from the institutional ethics committee of the hospital. The study protocol will be useful for researchers and practitioners for conducting similar economic evaluation studies in their context.

The effect of phacoemulsification plus goniosynechialysis in acute and chronic angle closure patients with extensive goniosynechiae

BACKGROUND

Patients with primary angle closure/glaucoma (PAC/PACG) with extensive peripheral anterior synechiae (PAS), and coexisting cataract, increasingly have been treated with phacoemulsification combined with goniosynechialysis (Phaco-GSL). Since the mechanisms of acute and chronic PAC/PACG may differ, the treatment effect of this procedure also may differ. The purpose of this study was to establish whether there was a difference in the therapeutic effect of Phaco-GSL on these two groups of patients, the results of which could provide clinical evidence for improvement in treatment protocols for patients with PAC/PACG and extensive PAS.

METHODS

This study was a retrospective cohort study. Twenty-seven patients, 13 with acute PAC/PACG and 14 with chronic PAC/PACG, were treated surgically by Phaco-GSL. The intraocular pressure (IOP), surgical success rate, the need of medication, the extent of PAS, the time and the rate of recurrence of PAS (re-PAS) and other indicators were observed post-operatively for at least 3 months.

RESULTS

After surgery, IOP decreased (preoperative vs postoperative: 29.77 ± 11.55 mmHg vs 14.92 ± 1.66 mmHg in the acute group and 26.00 ± 11.2 mmHg vs 14.93 ± 2.7 mmHg in the chronic group), the extent of PAS reduced (preoperative vs. postoperative: 314.23 ± 49.07° vs 116.54 ± 73.78° in the acute group and 285.00 ± 53.28° vs 156.43 ± 56.35° in the chronic group), the topical and systemic anti-glaucoma drug requirements decreased, in both groups and in the acute group, respectively. Compared with the acute group, the success rate (acute vs chronic: 100% vs 64.3%) was lower in the chronic group, while the incidence of re-PAS (acute vs chronic: 30% vs 83.3%) were higher in the chronic group. All differences mentioned above were statistically significant (p < 0.05). In addition, there were five patients in total who showed re-PAS of more than 90° (4 in chronic group and 1 in acute group) and all these re-PASs formed within 1 week postoperatively.

CONCLUSION

Although Phaco-GSL is effective in both groups, there may be differences in the effect between the two groups. Chronic patients are more susceptible to re-PAS. Thus, these patients should be observed closely and treated appropriately in the early post-surgical time period.

Prevalence of Normal-Tension Glaucoma in the Chinese Population: A Systematic Review and Meta-Analysis

PURPOSE

To investigate the prevalence of normal-tension glaucoma (NTG) in the Chinese population through systematic review and meta-analysis.

DESIGN

Systematic review and meta-analysis.

METHODS

All Chinese population-based studies that reported the prevalence of NTG were identified. We searched PubMed and Chinese databases including Wanfang, China National Knowledge Infrastructure, and VIP for studies published before December 31, 2017. Random effects meta-analysis was conducted to estimate the pooled prevalence of NTG.

RESULTS

Twelve studies were included in this review and meta-analysis, including 9 population-based studies and 3 studies from glaucoma clinics and managed care networks. The 9 population-based studies included a total of 30,892 subjects with 498 patients with primary open-angle glaucoma (POAG) and 354 patients with NTG. The prevalence of estimated NTG ranged from 0.36% to 1.98% and the percentage of NTG among POAG ranged from 51.43% to 83.58%. In the glaucoma clinic and managed care network studies, NTG prevalence was much lower. The overall pooled proportion of NTG among POAG in the Chinese population was 70.0% (95% confidence interval [CI] 62.0-77.0%). The overall pooled prevalence of POAG and NTG was 2.0% (95% CI 1.0-2.0%) and 1.0% (95% CI 1.0-1.0%), respectively. For the meta-regression of the NTG/POAG proportion, we found that age, gender, intraocular pressure, and China versus not China were not significantly associated with NTG/POAG prevalence, although the proportional prevalence decreased with increasing age category.

CONCLUSIONS

In this systematic review, we found that NTG is common among patients with POAG in the Chinese population. Our findings can help guide future glaucoma studies and public health guidelines in the Chinese population.

Cohort profile: design and methods in the eye and vision consortium of UK Biobank

PURPOSE

To describe the rationale, methods and research potential of eye and vision measures available in UK Biobank.

PARTICIPANTS

UK Biobank is a large, multisite, prospective cohort study. Extensive lifestyle and health questionnaires, a range of physical measures and collection of biological specimens are collected. The scope of UK Biobank was extended midway through data collection to include assessments of other measures of health, including eyes and vision. The eye assessment at baseline included questionnaires detailing past ophthalmic and family history, measurement of visual acuity, refractive error and keratometry, intraocular pressure (IOP), corneal biomechanics, spectral domain optical coherence tomography (OCT) of the macula and a disc-macula fundus photograph. Since recruitment, UK Biobank has collected accelerometer data and begun multimodal imaging data (including brain, heart and abdominal MRI) in 100 000 participants. Dense genotypic data and a panel of 20 biochemistry measures are available, and linkage to medical health records for the full cohort has begun.

FINDINGS TO DATE

A total of 502 665 people aged between 40 and 69 were recruited to participate in UK Biobank. Of these, 117 175 took part in baseline assessment of vision, IOP, refraction and keratometry. A subgroup of 67 321 underwent OCT and retinal photography. The introduction of eye and vision measures in UK Biobank was accompanied by intensive training, support and a data monitoring quality control process.

FUTURE PLANS

UK Biobank is one of the largest prospective cohorts worldwide with extensive data on ophthalmic diseases and conditions. Data collection is an ongoing process and a repeat of the baseline assessment including the questionnaires, measurements and sample collection will be performed in subsets of 25 000 participants every 2-3 years. The depth and breadth of this dataset, coupled with its open-access policy, will create a powerful resource for all researchers to investigate the eye diseases in later life.

Prevalence of Primary Glaucoma as Diagnosed by Study Optometrists of L. V. Prasad eye Institute - Glaucoma Epidemiology and Molecular Genetics Study

PURPOSE

To report the prevalence of primary glaucoma as identified by study optometrists of the L. V. Prasad Eye Institute - Glaucoma Epidemiology and Molecular Genetics Study (LVPEI-GLEAMS).

METHODS

Two study optometrists and a total number of 3833 individuals participated in the LVPEI-GLEAMS. All subjects underwent a complete medical history and comprehensive eye examination including slit lamp photography, imaging of anterior and posterior segment, frequency doubling technology and standard automated perimetry including gonioscopy with a Sussman 4 mirror goniolens, post dilated evaluation of the optic disc and fundus was done with a 90 D lens by the study optometrist. A diagnosis of primary open angle glaucoma (POAG), primary angle closure suspect (PACS), primary angle closure (PAC), primary angle closure glaucoma (PACG), normal tension glaucoma (NTG), glaucoma/disc suspect or no glaucoma was made based on the clinical examination.

RESULTS

Estimated prevalence of OAG (POAG and NTG) was 1.07% (0.74-1.39), PACS 2.03% (1.58-2.48), PAC 1.77% (1.35-2.19), PACG 0.21% (0.06-0.35) as identified by the study optometrists on site.

CONCLUSIONS

Prevalence of all the categories of primary glaucoma, as reported by the study optometrists of LVPEI-GLEAMS was comparable to previous findings of other regions in South India.

Eight-Year Incidence of Open-Angle Glaucoma in the Tema Eye Survey

PURPOSE

To determine the incidence of open-angle glaucoma (OAG) and its risk factors in the Tema Eye Survey in Ghana, West Africa.

DESIGN

Longitudinal, observational population-based study.

PARTICIPANTS

One thousand two hundred five of 1500 participants 40 years of age or older selected randomly from 5603 participants originally drawn from the population and who had undergone a baseline examination.

METHODS

All participants underwent baseline and follow-up ophthalmologic examinations 8 years apart. Glaucoma diagnosis was determined based on the International Society for Geographical and Epidemiologic Ophthalmology criteria.

MAIN OUTCOME MEASURES

Incidence and odds ratio (OR).

RESULTS

The response rate was 80.3%. Of 1101 nonglaucomatous participants at baseline who had complete follow-up data, 4.6% (95% confidence interval [CI], 3.7%-5.2%) demonstrated OAG over the 8-year period, or 0.58% (95% CI, 0.4%-0.8%) per year. The 8-year incidence increased with age from 3.1% in those 40 to 49 years old to 7.0% in those 60 to 69 years old. Baseline risk factors for incident OAG were male gender (OR, 2.1; 95% CI, 1.1-4.0; P = 0.025), older age relative to those 40 to 49 years old (those 50-50 years old: OR, 2.6; 95% CI, 1.2-5.7; those 60-69 years old: OR, 4.3; 95% CI, 2.0-8.8; and for those 70 years of age and older: OR, 6.3; 95% CI, 2.6-15.4; all P < 0.001), higher intraocular pressure (IOP; OR, 1.4; 95% CI, 1.1-1.8; P < 0.001), larger vertical cup-to-disc ratio (OR, 5.8; 95% CI, 5.2-6.6; P < 0.001), and thinner central cornea (OR, 1.2; 95% CI, 1.03-1.5; P = 0.013). A separate analysis performed with central corneal thickness-based IOP correction did not change the outcome of the associative model of incident glaucoma.

CONCLUSIONS

The incidence of OAG is higher in this population than reported in nonblack populations outside Africa. This is important not only in Ghana and probably other West African countries but also wherever people of the West African diaspora reside. These data enhance our understanding of the epidemiologic factors of OAG in this setting and may serve as reference for public health policy and planning.

Community care for diabetic retinopathy and glaucoma in India: A panel discussion

Diabetic retinopathy (DR) and glaucoma are emerging causes of blindness and visual impairment in India and the world. Both diseases do not have any early warning symptoms, and once the symptoms appear, the diseases are reasonably advanced. Because of the long-standing nature of the diseases, one cannot adopt the cataract detection and treatment model so successfully developed in India. It requires an altogether different approach for screening and related infrastructure including human capital development. The solutions developed to reduce the burden of DR/glaucoma should be customized to urban, semi-urban, and rural areas. Greater advocacy, improving the health-seeking behavior, development of infrastructure and skilled personnel appropriate for the points of care, and an emphasis in comprehensive eye care are some of the solutions.

Prevalence and risk factors of glaucoma in an adult population from Shahroud, Iran

Purpose

To determine the prevalence of glaucoma and its risk factors in a 40- to 64-year-old Iranian population.

Methods

In this cross-sectional study, 6311 individuals between the ages of 40–64 years old in Shahroud, a northeastern city in Iran, were selected through multistage cluster sampling. All participants underwent eye exams, optometry, and imaging. They had stereoscopic optic disc photography, visual field evaluation, and their intraocular pressure (IOP) was measured by ophthalmologists before pupil dilation. Glaucoma was defined by the standardized criteria, offered by the International Society for Geographical and Epidemiological Ophthalmology (ISGEO).

Results

Of the 5190 people who participated in the study (82.2%), data from 4637 people were used in the analysis. The prevalence of glaucoma was 1.92% [95% confidence intervals (CI): 1.53–2.31]; 1.4% (95% CI: 0.96–1.84) in women and 2.62% (95% CI: 1.95–3.28) in men. Glaucoma prevalence was 0.9% in the 40–44 years age group, and significantly increased to 3.55% in the 60–64 years age group. In the multiple logistic regression model, age [odds ratio (OR) = 1.08, 95% CI: 1.05–1.12], IOP (OR = 1.04, 95% CI: 1.01–1.06), axial length (OR = 1.34, 95% CI: 1.1–1.63), corneal radius of curvature (OR = 2.76, 95% CI: 1.26–6.06), and corneal diameter (OR = 0.63, 95% CI: 0.46–0.87) showed significant statistical association with glaucoma.

Conclusions

The prevalence of glaucoma was considerably high at older ages. Major risk factors confirmed by this study included older age and high IOP. Certain ocular biometric components such as the axial length and the corneal radius of curvature must be noted as important glaucoma risk factors at younger ages.

Simplifying "target" intraocular pressure for different stages of primary open-angle glaucoma and primary angle-closure glaucoma

Lowering of intraocular pressure is currently the only therapeutic measure for Glaucoma management. Many longterm, randomized trials have shown the efficacy of lowering IOP, either by a percentage of baseline, or to a specified level. This has lead to the concept of 'Target" IOP, a range of IOP on therapy, that would stabilize the Glaucoma/prevent further visual field loss, without significantly affecting a patient's quality of life. A clinical staging of Glaucoma by optic nerve head evaluation and perimetric parameters, allows a patient's eye to be categorized as having - mild, moderate or severe Glaucomatous damage. An initial attempt should be made to achieve the following IOP range for both POAG or PACG after an iridotomy. In mild glaucoma the initial target IOP range could be kept as 15-17 mmHg, for moderate glaucoma 12-15 mmHg and in the severe stage of glaucomatous damage 10-12 mmHg. Factoring in baseline IOP, age, vascular perfusion parameters, and change on perimetry or imaging during follow up, this range may be reassessed over 6 months to a year. "Target" IOP requires further lowering when the patient continues to progress or develops a systemic disease such as a TIA. Conversely, in the event of a very elderly or sick patient with stable nerve and visual field over time, the target IOP could be raised and medications reduced. An appropriate use of medications/laser/surgery to achieve such a "Target" IOP range in POAG or PACG can maintain visual fields and quality of life, preventing Glaucoma blindness.

The Prevalence of Pseudoexfoliation and the Long-term Changes in Eyes With Pseudoexfoliation in a South Indian Population

PURPOSE

To report the prevalence, long-term changes and associated factors for pseudoexfoliation (PEX) in a population aged 40 years and above from rural and urban south India.

MATERIALS AND METHODS

At baseline (the Chennai Glaucoma Study), 7774 subjects were examined. After 6 years, as a part of the incidence study, 133 of the 290 subjects diagnosed with PEX at baseline were reexamined for long-term changes. Participants had detailed examination at base hospital.

RESULTS

At baseline PEX was noted in 290 [3.73%, 95% confidence interval (CI), 3.3-4.2] subjects. It was associated with glaucoma in 24 (8.3%), ocular hypertension (OHT) in 21 (7.2%), and occludable angles in 24 (8.3%) subjects. The age-adjusted and sex-adjusted prevalence was 3.41% (95% CI, 3.39-3.43). Increasing age was a significant associated factor. Using the 40- to 49-year age group as a reference, the odds ratio increased from 8.4 (95% CI, 4.1-17.1) for the 50- to 59-year age group to 51.2 (95% CI, 25.8-101.6) for the 70 years and above age group. Other associated factors were rural residence (P<0.001), higher intraocular pressure (P<0.001), cataract (P<0.001), being underweight (P=0.01), manual labor (P=0.03), and aphakia (P<0.001). Of the 133 subjects reexamined, 8 (6.0%) subjects developed glaucoma and all had OHT at baseline. Rates of cataract surgery were (P<0.001) higher in subjects with PEX.

CONCLUSION

Prevalence of PEX was higher in rural population and baseline OHT was a significant factor for conversion to glaucoma.

Prevalence of retinal nerve fiber layer defects: The Korea National Health and Nutrition Examination Survey 2008-2012

Purpose

To investigate the prevalence and associated factors of retinal nerve fiber layer defects (RNFLDs) in a Korean population.

Methods

The Korea National Health and Nutrition Examination Survey (KNHANES) is a population-based study using a complex, stratified, multistage, probability-cluster survey. We performed a review of 2008–2012 data from the KNHANES. Two masked ophthalmologists evaluated fundus photography to detect RNFLDs. All participants underwent ocular and systemic evaluations.

Results

A total of 28,637 subjects aged ≥ 19 years with at least one evaluable fundus photograph were enrolled. The estimated prevalence of RNFLDs in this Korean population was 4.8% (95% confidence interval, 4.4%–5.3%). The estimated percentages of glaucomatous RNFLD and non-glaucomatous RNFLD subjects were 34.4% and 65.6%, respectively. In a multivariate analysis, the prevalence of RNFLDs was significantly associated with older age (P < 0.001), male gender (P = 0.047), glycosylated hemoglobin (P = 0.048), disc hemorrhage (P = 0.016), ISNT rule (P < 0.001), and vertical cup to disc ratio (P < 0.001).

Conclusions

The prevalence of RNFLDs in a large Korean population-based sample with a minimum age of 19 years was 4.8%. RNFLD prevalence was associated with old age, male gender, glycosylated hemoglobin, disc hemorrhage, and glaucomatous optic disc.

Public awareness of common eye diseases in Jordan

BACKGROUND

Cataract, glaucoma, diabetic retinopathy and dry eye disease are common with high prevalence in Jordan. This study aims to assess the awareness of these ocular diseases among Jordanian population.

METHOD

A self-designed questionnaire was developed in Arabic and used to interview people in different provinces of Jordan. Socio-demographic data e.g. age, gender and level of education was reported. Public awareness of four ocular diseases; cataract, glaucoma, diabetic retinopathy (DR) and dry eye disease (DED) was assessed. Questions about familiarity with the diseases, familiarity with their risk factors and participants' source of knowledge were asked. Moreover, awareness of the effect of these disease on the eye whether they are blinding, preventable, treatable and/or the vision is back to normal following treatment was also assessed.

RESULTS

A total of 802 participants (232 males and 570 females) completed the questionnaire. The average age (± standard deviation) of the study participants was 28 ± 11.6 (range 18 to 80 years old). Awareness of cataract, glaucoma, DR and DED was reported by 31%, 38%, 37% and 52% of the study population, respectively. Family/relatives/friends and mass media appeared to be the most common sources of knowledge. Age and level of education of the participants were significantly associated with the level of disease awareness.

CONCLUSION

This work shows that the level of awareness of the four ocular diseases among Jordanians is good and compares with many reports in the developed and developing countries. Familiarity and knowledge about ocular diseases is essential as it would increase the chance of the subject being tested and thus diagnosed early enough if any problem occurred. Better understanding of the disease would encourage subjects to seek medical care sooner which in turn would prevent visual impairment. Therefore, awareness campaigns should be made to target unaware population.

Performance of an iPad Application to Detect Moderate and Advanced Visual Field Loss in Nepal

PURPOSE

To evaluate the accuracy and efficiency of Visual Fields Easy (VFE), a free iPad app, for performing suprathreshold perimetric screening.

DESIGN

Prospective, cross-sectional validation study.

METHODS

We performed screening visual fields using a calibrated iPad 2 with the VFE application on 206 subjects (411 eyes): 210 normal (NL), 183 glaucoma (GL), and 18 diabetic retinopathy (DR) at Tilganga Institute of Ophthalmology, Kathmandu, Nepal. We correlated the results with a Humphrey Field Analyzer using 24-2 SITA Standard tests on 373 of these eyes (198 NL, 160 GL, 15 DR).

RESULTS

The number of missed locations on the VFE correlated with mean deviation (MD, r = 0.79), pattern standard deviation (PSD, r = 0.60), and number of locations that were worse than the 95% confidence limits for total deviation (r = 0.51) and pattern deviation (r = 0.68) using SITA Standard. iPad suprathreshold perimetry was able to detect most visual field deficits with moderate (MD of -6 to -12 dB) and advanced (MD worse than -12 dB) loss, but had greater difficulty in detecting early (MD better than -6 dB) loss, primarily owing to an elevated false-positive response rate. The average time to perform the Visual Fields Easy test was 3 minutes, 18 seconds (standard deviation = 16.88 seconds).

DISCUSSION

The Visual Fields Easy test procedure is a portable, fast, effective procedure for detecting moderate and advanced visual field loss. Improvements are currently underway to monitor eye and head tracking during testing, reduce testing time, improve performance, and eliminate the need to touch the video screen surface.

Prevalence of glaucoma in Eastern India: The Hooghly River Glaucoma Study

Context:

Glaucoma is the leading cause of global irreversible blindness. No recent study with adequate sample size has been carried out to estimate glaucoma prevalence in Eastern India.

Aims:

The aim of this study was to assess and compare the prevalence and types of glaucoma in a rural and urban East Indian population.

Settings and Design:

The Hooghly River Glaucoma Study (HRGS) is a population-based cross-sectional study from West Bengal. A tertiary hospital in Kolkata was our urban study center. Our rural study area included 28 contiguous villages from the district of Hooghly surrounding the rural base hospital located at Dhobapara in village Bakulia. Individuals aged 40 years and above were included in this study.

Subjects and Methods:

All subjects underwent a detailed ophthalmic examination at our base hospitals including applanation tonometry, ultrasound pachymetry, gonioscopy, and frequency doubling technology perimetry. Glaucoma was defined using modified International Society of Geographical and Epidemiological Ophthalmology criteria.

Statistical Analysis Used:

Analysis was performed using Chi-square test and multiple logistic regression using SPSS.

Results:

Totally, 14,092 individuals participated; 2.7% were detected to have glaucoma in rural arm and 3.23% in urban arm (P < 0.001). In urban population, 2.10% had primary open angle glaucoma (POAG), 0.97% had primary angle closure glaucoma (PACG), and 0.15% had secondary glaucoma. In rural population, 1.45% had POAG, 1.15% had ACG, and 0.10% had secondary glaucoma.

Conclusions:

HRGS is the largest population-based glaucoma study in India to date with glaucoma prevalence comparable to other landmark Indian studies. POAG was the most common form of glaucoma in our study population as well. PACG was more common in this region than previously thought.

Glaucoma awareness amongst glaucoma patients seeking a second opinion

PURPOSE

The aim of the study was to assess level of glaucoma awareness amongst glaucoma patients by studying characteristics amongst urban and rural glaucoma populations in North India.

METHODS

A questionnaire was designed and administered after appropriate validation amongst patients to identify determinants of glaucoma awareness. Trained personnel delivered the 11 questions to 1506 patients, aged 18 and above through random sampling. The questionnaire evaluated source of awareness, education, gender, location and age on the level of awareness of glaucoma. The outcomes were assessed based on patient's responses.

RESULTS

Age and education essay a significant role in glaucoma awareness. Awareness levels increased with the level of education significantly in both rural and urban settings (P value <0.001). Patients from lower educational backgrounds were significantly more likely to share their condition with their spouse compared to those with higher education (P value <0.001). Compared to the middle aged and elderly, young adults were less aware that glaucoma could run in families (P value <0.015).

CONCLUSIONS

There is a significant gap in the knowledge about glaucoma and its risks in both urban and rural set-ups in Northern India necessitating active steps to spread awareness regarding glaucoma and its relation with blindness.

Repeatability and agreement of central corneal thickness measurement with non-contact methods: a comparative study

PURPOSE

To compare the central corneal thickness (CCT) measurements and reliability of RTVue XR-100 anterior segment optical coherence tomography (AS-OCT), AL-scan optical biometer and Schwind Sirius anterior segment analysis system.

METHODS

The CCT was measured in one hundred and twenty-seven eyes of 127 healthy subjects with AS-OCT, AL-scan and Sirius system. Mean CCT was compared among the instruments, and the level of agreement was assessed using Bland-Altman plots. One eye each of 30 subjects was randomly assigned for intrasession intraoperator and interoperator repeatability which was assessed using coefficient of variation and intraclass correlation coefficient.

RESULTS

Mean CCT with AS-OCT, AL-scan and Sirius system was 496.72 ± 32.75, 507.43 ± 33.54 and 512.08 ± 33.1 µm, respectively. There was no statistically significant difference between AL-scan and Sirius system (p = 0.26). Significant difference was found between AS-OCT/AL-scan (p = 0.01) and AS-OCT/Sirius system (p < 0.0001). Bland-Altman analysis showed a high level of agreement between AL-Scan/Sirius system (Mean difference -4.6 µm) and a low level of agreement between AS-OCT/AL-scan (Mean difference -10.7 µm) and OCT/Sirius system (Mean difference -15.4 µm).

CONCLUSIONS

AS-OCT underestimated CCT measurements when compared to other two devices in healthy subjects. Hence, one must be cautious when analyzing the results from different machines and should be aware that the measurement values are not interchangeable.

Distribution of intraocular pressure, central corneal thickness and vertical cup-to-disc ratio in a healthy Iranian population: the Yazd Eye Study

PURPOSE

To determine the distribution of intraocular pressure (IOP), central corneal thickness (CCT) and vertical cup-to-disc ratio (VCDR) in the healthy Iranian population.

METHODS

This population-based, epidemiologic study evaluated Iranian aged 40-80 years, residing in Yazd, Iran, in 2010-2011. Eligible subjects were selected by cluster random sampling. Each participant underwent an interview and ophthalmologic examination including slit lamp examination, Goldmann applanation tonometry, binocular optic disc evaluation, stereoscopic fundus photography, ultrasonic pachymetry and visual field testing.

RESULTS

Of 2320 eligible individuals, 2098 subjects (response rate of 90.4%) participated in the study. One eye from 1159 subjects (total of 2262 normal eyes) were randomly selected for the purpose of the study. Mean age was 53.1 ± 9.6 years. Mean IOP, CCT and VCDR were 14.2 ± 2.5 mmHg, 543 ± 37 μm and 0.32 ± 0.14, respectively. Multiple regression analysis showed a significant correlation between IOP and age (regression coefficient = 0.02 per year, p = 0.015), CCT (regression coefficient = 0.02 per micron, p < 0.001), Spherical equivalent (regression coefficient = -0.15 per dioptre, p = 0.0.024) and smoking (regression coefficient = 0.89 higher for smokers, p = 0.009); it also showed a significant correlation between CCT with spherical equivalent (regression coefficient = 3.6 per dioptre, p = 0.002) and IOP (regression coefficient = 3.6 per mmHG, p < 0.001). There was no significant correlation with VCDR.

CONCLUSIONS

Mean IOP, CCT and VCDR were 14.2 ± 2.5 mmHg, 543 ± 35 μm and 0.32 ± 0.14, respectively, in healthy Iranians that is different from other ethnicities. It seems advisable to pay attention to ethnicity for interpretation of each person's variables.

Relationship between systemic hypertension, perfusion pressure and glaucoma: a comparative study in an adult Indian population

AIMS

To study the relationship between blood pressure (BP), intraocular pressure (IOP), mean ocular perfusion pressure (MOPP) and primary open angle glaucoma (POAG) in patients with hypertension and compare it to a control group of normotensives.

DESIGN

Cross-sectional observational study.

MATERIALS AND METHODS

A total of 108 subjects with primary hypertension and 100 age-matched controls without hypertension were enrolled for the study. IOP measurement using Noncontact Tonometer and dilated fundus evaluation using + 90 D lens were done for all cases. Single recording of BP was taken. Gonioscopy, Humphrey's central visual fields, optical coherence tomography and pachymetry were done for all subjects with IOP > 21 mm Hg or C: D ratio ≥ 0.5 or asymmetry of > 0.2.

STATISTICAL ANALYSIS

Univariate and multivariate multinomial regression models were used to determine the association between covariates and risk of glaucoma or glaucoma suspect.

RESULTS

There was no difference in the glaucoma status between subjects with and without hypertension. Subjects on antihypertensive medications were 1΍ times more likely to have suspicious glaucoma (odds ratio [OR] =1.56] and nearly twice as likely to have POAG (OR = 1.85). In addition, we found a 31% and 12% reduction in risk of having POAG (95% confidence interval [CI] =13-45%, P = 0.001) and glaucoma suspect (95% CI = 2-21%, P = 0.03) respectively with every 1 mm Hg increment in MOPP.

CONCLUSION

Subjects on antihypertensive medications are more likely to have either glaucoma or glaucoma suspect, and higher ocular perfusion pressure offers relative protection from glaucomatous damage.

Distribution of intraocular pressure and its determinants in an Iranian adult population

AIM

To determine the distribution of intraocular pressure (IOP) and its determinants in an Iranian population.

METHODS

In a cross-sectional survey, random cluster sampling was conducted from the 40-64 years old population of Shahroud, in the north of Iran. All participants had optometry and ophthalmic exams. IOP was determined using the Goldmann tonometry method and biometric components were measured.

RESULTS

Of the 6311 people selected for the study, 5190 (82.2%) participated. The mean age of the participants was 50.9±6.2y and 58.7% of them were female. Mean IOP was 12.87±2.27 mm Hg. In this study 0.3% of the participants had an IOP higher than 21 mm Hg. The multiple linear regression model revealed that sex (Coef=-0.30; 95% CI: -0.43 to -0.17), diabetes (Coef=0.43; 95% CI: 0.19 to 0.67), high systolic blood pressure (Coef=0.02; 95% CI: 0.01 to 0.02), high body mass index (BMI) (Coef=0.03; 95% CI: 0.01 to 0.04), higher education (Coef=0.02, 95% CI: 0.01 to 0.04), thicker central corneal thickness (Coef=0.01; 95% CI: 0.01 to 0.02), and myopic shift in spherical equivalent (Coef=-0.14; 95% CI: -0.18 to -0.10) significantly correlated with high IOP.

CONCLUSION

The IOP in this 40-64 years old population is low overall. In the north of Iran, average IOP is statistically significantly correlated with female sex, diabetes, higher BMI, systolic blood pressure, higher education, thicker cornea, and myopic refractive error.

Risk factors for open-angle glaucoma in Nigeria: results from the Nigeria National Blindness and Visual Impairment Survey

BACKGROUND

The glaucoma-specific blindness prevalence in Nigeria (0.7 %, 95 % CI 0.6-0.9 %) among those aged ≥40 years is one of the highest ever reported. This study determined the risk factors for open-angle glaucoma (OAG) in adults examined in the Nigeria National Blindness and Visual Impairment Survey.

METHODS

A nationally representative sample of 13,591 people aged ≥40 years in 305 clusters in Nigeria were examined (response rate 90.4 %) between January 2005 to June 2007. Everyone had logMAR visual acuity measurement, Frequency Doubling Technology (FDT) visual field testing, autorefraction, A-scan biometry and optic disc assessment. Full ocular examination (n = 6397), included Goldmann applanation tonometry. Values for defining glaucoma using International Society of Geographical and Epidemiological Ophthalmology criteria were derived from the study population. Disc images were graded by Moorfields Eye Hospital Reading Centre. Socio-demographic factors (age, gender, ethnicity, literacy and place of residence), ocular parameters (intraocular pressure [IOP], axial length and mean ocular perfusion pressure [MOPP]) and systemic parameters (blood pressure, blood glucose and body mass index [BMI]) were assessed for association with OAG.

RESULTS

Thirteen thousand eighty-one (96 %) of 13,591 participants had vertical cup:disc ratio measured in at least one eye. 682 eyes of 462 participants were classified as OAG, with 12,738 controls. In univariate analyses the following were associated with OAG: increasing age, male gender, Igbo and Yoruba ethnic groups, illiteracy, longer axial length, higher IOP, lower MOPP, greater severity of hypertension and low BMI (underweight). In multivariate analysis, increasing age (odds ratio [OR] 1.04, 95 % CI 1.03-1.05), higher IOP (OR 1.22, 95 % CI 1.18-1.25) and Igbo ethnicity (OR 1.73, 95 % CI 1.18-2.56) were independent risk factors for OAG.

CONCLUSION

Case detection strategies for OAG should be improved for those aged ≥40 years and for ethnic groups most at risk as a public health intervention.

Aniridic Glaucoma: Long-term Visual Outcomes and Phenotypic Associations

PURPOSE

The aim of this study was to evaluate long-term visual outcomes in patients with aniridic glaucoma.

DESIGN

Retrospective noncomparative observational case series.

MATERIALS AND METHODS

A review of medical records of 128 eyes of 64 consecutive patients with aniridic glaucoma, diagnosed after the age of 5 years was analyzed. The parameters studied included age at presentation, family history, baseline intraocular pressure (IOP), type and the number of surgical interventions, and associated comorbidities.

PRIMARY OUTCOME MEASURE

Best corrected visual acuity (BCVA) in the better eye.

RESULTS

Mean age at presentation was 15.86±10.11 years (range, 5 to 47 y). The average follow-up was 7.69±4.98 years (range, 1 to 17 y). At the final follow up only 18 patients had BCVA better than 6\60 and only 5 patients had BCVA of >6/18. Seventeen of the 64 (26.5%) patients developed phthisis in 1 eye. The final visual outcomes were not associated with age at presentation (P=0.64) or sex (P=0.76); however, those with a higher baseline IOP (P=0.017), those with familial aniridia (P=0.037), and those who underwent more number of surgical interventions had poorer visual outcomes (P=0.004). Kaplan-Meier analysis demonstrated the probability of bilateral blindness to be 69.8% and 97.6% at 5 and 10 years, respectively.

CONCLUSIONS

Long-term visual outcomes after therapy among aniridic glaucoma patients remain poor. Higher baseline IOP, the presence of familial aniridia, and a history of greater number of surgical interventions are associated with poorer long-term visual outcomes.

Awareness, knowledge, and practice: a survey of glaucoma in north Indian rural residents

Background:

Studies done on the prevalence of glaucoma have reported a high proportion of undiagnosed patients. Late diagnosis is related to increased risk of glaucoma associated with visual disability. Lack of awareness and non-availability of appropriate screening procedures are among the major reasons for non-diagnosis or late diagnosis of glaucoma. The present study has been undertaken to evaluate the level of awareness about glaucoma among the North Indian rural population.

Materials and Methods:

A group-administered, questionnaire-based survey, involving 5000 rural residents (aged 20 and above) was conducted through random sampling. The questionnaire was structured to evaluate the level of awareness and knowledge about glaucoma and the effect of gender, education status, and glaucoma diagnosis was also studied. The source of awareness about glaucoma was also questioned.

Results:

Of the 5000 individuals enrolled for the survey, responses from 4927 (98.5%; 95% Confidence Interval (CI): 98.2 - 98.9) participants, including 3104 males (63%; 95% CI: 61.7 - 64.3) and 1823 females (37%; 95% CI: 35.7 - 38.3) were evaluated. A total of 409 (~8.3%; 95% CI: 7.6 - 9.14) respondents were aware about glaucoma and only 93 (1.89%; 95% CI: 1.55 - 2.31) were qualified as having knowledge about glaucoma as per the set questionnaire. Education was the only variable significantly correlated (P value < 0.001) with the awareness and knowledge of glaucoma out of the parameters included in this study. Close acquaintance with a glaucoma patient was the most common source of information.

Conclusions:

There is a lack of awareness about glaucoma among the rural residents of North India. The study findings stress the need to spread awareness about glaucoma for prevention of glaucoma-related blindness.

Six-year incidence of ocular hypertension in a South Indian population: the Chennai eye disease incidence study

AIMS

To report the 6-year incidence and risk factors for ocular hypertension (OHT) in a population-based study in southern India.

METHODS

6 years after baseline evaluation, 56.9% subjects (participants:non-participants, 4421:3353) were re-examined at the base hospital. Incident OHT was defined as an intraocular pressure above the 97.5th centile for the population with no evidence of glaucoma in the 2852 phakic subjects, 40 years or older. Subjects with trauma, laser or incisional surgery at baseline or follow-up were excluded (total exclusions: 1569).

RESULTS

Incidence of OHT at 6 years was 62/2852 subjects (2.17% (95% CI 1.64% to 2.71%, men:women, 36:26)). Incidence was higher in the rural cohort as compared with the urban cohort (80.6% vs 19.4%, p<0.001). A higher baseline intraocular pressure (with increasing OR: 16-18 mm Hg (OR 4.0, 95% CI 2.1 to 7.9), 19-21 mm Hg (OR 11.4, 95% CI 5.7 to 22.9), 22-24 mm Hg (OR 42.6, 95% CI 11.0 to 164.8, in the urban cohort)) and increasing age (50-59 years (OR 1.9, 95% CI 1.1 to 3.3), 70 years and above (OR 3.6, 95% CI 1.2 to 10.6)) were significantly associated risk factors for incident OHT.

CONCLUSIONS

A significant proportion of this normal population converted to OHT. A higher incidence of conversion was seen in the rural population.

Systemic hypertension as a risk factor for open-angle glaucoma: a meta-analysis of population-based studies

BACKGROUND/AIMS

Systemic hypertension is thought to increase the risk for developing open-angle glaucoma (OAG) through several mechanisms. However, previous epidemiological studies have shown conflicting results regarding this potential association. We systematically evaluated this issue by conducting a meta-analysis of population-based studies.

METHODS

A comprehensive search for articles published before 31 March 2014 was performed using PubMed, Embase, and reference lists. The pooled odds ratio (OR) was calculated using the fixed- and random-effects models, and meta-regression was performed according to age. Subgroup analyses were also conducted, and publication bias was assessed using a funnel plot and Egger's regression test.

RESULTS

This meta-analysis included 16 studies involving 60,084 individuals, with substantial homogeneity among the studies. The pooled OR for OAG was 1.22 (95% confidence interval, CI: 1.09-1.36) using the fixed-effects model and 1.22 (95% CI: 1.08-1.37) using the random-effects model in all included studies. For subgroup analyses, the pooled OR for high-tension glaucoma (HTG) was higher than that for normal-tension glaucoma (NTG) (OR=1.92 and 0.94, respectively). No significant difference was detected between Asian and Western populations, and no publication bias was detected in either analysis.

CONCLUSIONS

Systemic hypertension increases the risk for developing OAG, especially in those with HTG.

Age-related changes in central corneal thickness in normal eyes among the adult Lithuanian population

Background

The purpose of this study was to estimate mean central corneal thickness (CCT) and determine whether there are any correlations between CCT, age, and sex in the adult Lithuanian population.

Methods

A total of 1,650 Caucasians of Lithuanian origin (aged 18–89 years) comprising 688 (41.7%) men and 962 (58.3%) women were examined. Subjects were stratified by age into seven groups. CCT was measured using ultrasonic pachymetry. Correlations between CCT, age, and sex were sought.

Results

Mean (± standard deviation) CCT for both eyes was 544.6±30.5 μm. Mean CCT was 545.2±30.5 μm in the left eye and 544.6±30.5 μm in the right eye, and was 545.0±25.6 μm in men and 544.4±33.5 μm in women. Mean CCT was 550.8±35.7 μm in subjects aged 18–29 years, 557.5±27.6 μm in those aged 30–39 years, 551.3±31.4 μm in those aged 50–59 years, 544.0±31.4 μm in those aged 50–59 years, 544.2±31.6 μm in those aged 60–79 years, 535.1±27.8 μm in those aged 70–79 years, and 530.1±16.8 μm in those aged 80–89 years. No statistically significant difference in CCT was found between the sexes (P>0.05). However, there was a significant difference in subjects aged 18–29 years; men had higher CCT than women (P<0.05). A statistically significant negative correlation was found between CCT and age (r=-0.263, P<0.05) that was stronger in men (r=-0.406, P<0.05) than in women (r=-0.118, P<0.05).

Conclusion

The mean CCT in adult Lithuanians was 544.6±30.5 μm, of the left eye 545.2±30.5 μm and of the right – 544.6±30.5 μm. CCT of the right eye was equal to the CCT of both eyes. Mean CCT was 545.0±25.6 μm in men and 544.4±33.5 μm in women. Young men tended to have higher CCT than women. CCT decreases over the lifetime, meaning that older people have thinner corneas. CCT’s dependence on age is stronger in men.

Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis

PURPOSE

Glaucoma is the leading cause of global irreversible blindness. Present estimates of global glaucoma prevalence are not up-to-date and focused mainly on European ancestry populations. We systematically examined the global prevalence of primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG), and projected the number of affected people in 2020 and 2040.

DESIGN

Systematic review and meta-analysis.

PARTICIPANTS

Data from 50 population-based studies (3770 POAG cases among 140,496 examined individuals and 786 PACG cases among 112 398 examined individuals).

METHODS

We searched PubMed, Medline, and Web of Science for population-based studies of glaucoma prevalence published up to March 25, 2013. Hierarchical Bayesian approach was used to estimate the pooled glaucoma prevalence of the population aged 40-80 years along with 95% credible intervals (CrIs). Projections of glaucoma were estimated based on the United Nations World Population Prospects. Bayesian meta-regression models were performed to assess the association between the prevalence of POAG and the relevant factors.

MAIN OUTCOME MEASURES

Prevalence and projection numbers of glaucoma cases.

RESULTS

The global prevalence of glaucoma for population aged 40-80 years is 3.54% (95% CrI, 2.09-5.82). The prevalence of POAG is highest in Africa (4.20%; 95% CrI, 2.08-7.35), and the prevalence of PACG is highest in Asia (1.09%; 95% CrI, 0.43-2.32). In 2013, the number of people (aged 40-80 years) with glaucoma worldwide was estimated to be 64.3 million, increasing to 76.0 million in 2020 and 111.8 million in 2040. In the Bayesian meta-regression model, men were more likely to have POAG than women (odds ratio [OR], 1.36; 95% CrI, 1.23-1.52), and after adjusting for age, gender, habitation type, response rate, and year of study, people of African ancestry were more likely to have POAG than people of European ancestry (OR, 2.80; 95% CrI, 1.83-4.06), and people living in urban areas were more likely to have POAG than those in rural areas (OR, 1.58; 95% CrI, 1.19-2.04).

CONCLUSIONS

The number of people with glaucoma worldwide will increase to 111.8 million in 2040, disproportionally affecting people residing in Asia and Africa. These estimates are important in guiding the designs of glaucoma screening, treatment, and related public health strategies.

Population-based glaucoma prevalence studies in Asians

Glaucoma-related population-based studies from Japan, Mongolia, India, Singapore, Thailand, China, Bangladesh, Myanmar, Sri Lanka, and South Korea show a higher glaucoma prevalence in Asian patients, including a higher incidence of primary angle-closure glaucoma, than in white patients, although primary open-angle glaucoma (POAG) is still the most commonly reported. Among POAG, normal tension glaucoma predominates over high tension glaucoma, a distinctive finding. Risk factors for glaucoma in population-based studies in both Asian and white patients are similar, except that myopia is a greater risk factor in Asian patients. Diagnostic criteria differ among studies, some using the International Society of Geographic and Epidemiologic Ophthalmology (ISGEO) classification and others not. The devices used to observe the optic disk and test the visual field are also not uniform across studies. Moreover, the ages of patients, and whether rural or urban, were different. To allow reliable comparison of the results of epidemiologic studies, efforts to standardize the diagnostic criteria, devices, and the age range of the study population are required.

Predictors for incidence of primary open-angle glaucoma in a South Indian population: the Chennai eye disease incidence study

OBJECTIVE

To determine the 6-year incidence of primary open-angle glaucoma (POAG) and its associated predictors.

DESIGN

Population-based cohort study.

PARTICIPANTS

A total of 4316 subjects without POAG at baseline who were 40 years of age and older from a south Indian population.

METHODS

Participants were examined at baseline and after a 6-year interval. Detailed ophthalmic examination included applanation tonometry, gonioscopy, pachymetry, optic disc evaluation, and automated perimetry. Glaucoma was defined using the International Society of Geographical and Epidemiological Ophthalmology Classification. Multivariable logistic regression was performed to identify the baseline risk factors that could predict the incident POAG.

MAIN OUTCOME MEASURES

Six-year incidence of POAG and its associated risk factors.

RESULTS

In 6 years, incident POAG developed in 129 subjects (2.9%; 95% confidence interval [CI], 2.4-3.4; male-to-female ratio, 65:64). Baseline age was a risk factor. In reference to the group 40 to 49 years of age, the incidence increased from 2.3 (95% CI, 1.4-3.7) for the group 50 to 59 years of age to 3.5 (95% CI, 2.2-5.7) for the group 60 to 69 years of age (P<0.001). Other baseline risk predictors were urban residence (odds ratio [OR], 1.6; 95% CI, 1.1-2.2; P = 0.01), higher intraocular pressure (IOP; OR, 2.0; 95% CI, 1.5-2.6 per 10 mmHg; P<0.001), myopia (OR, 1.7; 95%, CI, 1.1-2.5; P<0.001), and axial length (OR, 1.5; 95% CI, 1.0-2.2 per millimeter; P = 0.03). Thinner corneas with higher IOP at baseline had the highest incidence of POAG. In 80% of the urban population and 100% of the rural population, incident glaucoma was previously undetected.

CONCLUSIONS

A significant proportion of this population demonstrated incident POAG. The baseline risk factors could help in identifying those at highest risk of disease.