Praveen K Nirmalan

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

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

Blindness and vision impairment in a rural south Indian population: the Aravind Comprehensive Eye Survey

OBJECTIVE To determine the prevalence of blindness and vision impairment in a rural population of southern India. DESIGN A population-based cross-sectional study. PARTICIPANTS A total of 17200 subjects aged 6 years or older, including 5150 subjects aged 40 years or older from 50 clusters representative of three southern districts of Tamil Nadu in southern India. METHODS All participants had preliminary screenings consisting of vision using a LogMAR illiterate E chart and anterior segment hand light examinations at the village level. Subjects aged 40 years or older were offered comprehensive eye examinations at the base hospital, including visual acuity using LogMAR illiterate E charts and refraction, slit-lamp biomicroscopy, gonioscopy, applanation tonometry, dilated fundus examinations, and automated Humphrey central 24-2 full threshold perimetry; subjects younger than 40 years of age who had any signs or symptoms of ocular disease were also offered comparable examinations at the base hospital. MAIN OUTCOME MEASURES Visual impairment was defined as best-corrected visual acuity <6/18, and blindness was defined using both Indian (<6/60) and World Health Organization (<3/60) definitions. RESULTS Comprehensive examinations at the base hospital were performed on 5150 (96.5%) of 5337 persons 40 years of age or older. Among those 40 years of age and older, presenting visual acuity at the <3/60 level was present in 4.3% (95% confidence interval [CI]: 3.8, 4.9) and 11.4% (95% CI: 10.6, 12.3) at the <6/60 level. After best correction, the corresponding figures were 1.0% (95% CI: 0.79, 1.2) and 2.1% (95% CI: 1.7, 2.5). Over 70% of subjects improved their vision by at least one line, and nearly a third by three lines after refraction. Age-related cataract was the most common potentially reversible blinding disorder (72.0%) among eyes presenting with blindness. CONCLUSIONS Blindness and vision impairment remain major public health problems in India that need to be addressed. Cataracts and refractive errors remain the major reversible causes for the burden of vision impairment in this rural population.

A randomised clinical trial comparing 2% econazole and 5% natamycin for the treatment of fungal keratitis

Aim: To compare 2% econazole and 5% natamycin in the management of fungal keratitis. Methods: A randomised clinical trial was performed using 2% econazole or 5% natamycin as the two treatment arms on patients presenting with culture positive fungal keratitis to the cornea service at Aravind Eye Care System, Madurai, India. Results: 116 patients were recruited, and 112 continued in the study. There were no significant differences between the two arms at baseline or for success (defined as a healed or healing ulcer) at final visit (p = 0.79). Conclusions: 2% Econazole appears to be as effective as 5% natamycin for the management of fungal keratitis.

The kariapatti pediatric eye evaluation project: Baseline ophthalmic data of children aged 15 years or younger in southern India

PURPOSE To estimate the prevalence of ocular morbidity among children of rural southern India before developing a service delivery model for community-based pediatric eye care. DESIGN Population-based cross sectional study. METHODS Trained field-workers performed door-to-door enumeration in 74 randomly selected villages of the Kariapatti block in southern India to identify children aged 15 years or younger and performed visual acuity measurements using Cambridge crowded cards and external eye examination with torchlight. Pediatric ophthalmologists further examined subjects with ocular problems identified by the field-worker. The clinical team performed repeat visual acuity measurements with Cambridge crowded cards, refraction, slit-lamp anterior segment examinations, and dilated posterior segment examinations at the screening site. The ophthalmologist identified and recorded one major cause for each visually impaired eye. RESULTS Field-workers screened 10605 (94.6%) of 11206 children enumerated, and identified 1441 (13.6%) children as requiring further clinical examination. An additional 449 children identified as normal by the field-worker were randomly chosen for repeat examinations at the screening sites. In all, 1578 (83.5%) of these 1890 children were examined at the screening site. According to World Health Organization criteria, 6.2 of 10000 children were blind; 42.9% of this blindness was potentially avoidable. Refractive errors (0.55%, 95% confidence interval: 0.41, 0.69) and strabismus (0.43%, 95% confidence interval: 0.30, 0.55) were the major ocular morbidity in this population. CONCLUSIONS Developing an appropriate service delivery model for this region will require a balance between the relatively low prevalence of morbidity and blindness and the need for service in this population.

Sex inequalities in cataract blindness burden and surgical services in south India

Aim: To determine sex inequalities in cataract blindness and surgical services in south India Methods: Details of lens status and cataract surgery were recorded for subjects aged 50 years and older identified through cluster sampling as part of population based cross sectional assessments of cataract blindness and surgical outcomes in three districts of south India. Results: Females were less likely to be operated on for cataract (adjusted OR 0.71, 95% CI: 0.57 to 0.87) although the cataract blindness burden was higher for females (p<0.001). Literacy of the subject was a major predictor for being operated on for cataract. Achieving equal surgical coverage between sexes will have resulted in an additional 25.3% reduction of cataract blindness. Conclusions: Eye care programmes in this population need to be sensitised to the substantial reduction in blindness possible by achieving equal surgical coverage between sexes.

Blindness and vision impairment in the elderly of Papua New Guinea

Background:  To estimate the magnitude and causes of blindness and vision impairment in Papua New Guinea for service delivery planning and ophthalmic education development.

Can Ocular Torsion be Measured Using the Slitlamp Biomicroscope

PURPOSE To evaluate and compare a stereo-biomicroscopic technique of ocular torsion measurement with fundus photographic technique. METHODS This prospective masked observational study included 72 eyes of 36 consecutive subjects with normal ocular motility. The disc-foveal angle was measured by two masked investigators using a slitlamp stereo-biomicroscopic and fundus photographic technique. RESULTS The mean age was 13.7 years (6 - 44 years), and 15 (41.6%) were males. The average torsion using the slitlamp technique was 5.5 +/- 3.3 degrees and 6.1 +/- 4.3 degrees with fundus photographic technique. Clinical agreement between the two techniques for 5 degree and 6 degree torsion was 81% and 90% respectively. The average difference between the two techniques was 3.0 +/- 2.6 degrees . The mean inter-ocular difference was 3.3 +/- 2.7 degrees (SD, 2.77) and 5.5 +/- 4.6 degrees using the slitlamp and fundus photographic technique respectively. The Pearson correlation coefficient (r2) was 0.5. CONCLUSION The fundus photographic technique remains the gold standard test for the measurement of ocular torsion. The slitlamp biomicroscopic method can be useful where a fundus camera is unavailable. Further studies are required to test the repeatability of these tests.

Contrast sensitivity and visual hallucinations in patients referred to a low vision rehabilitation clinic

Aim: To examine the association of reported visual hallucinations and measured visual parameters in adult patients referred for low vision rehabilitation. Methods: All patients (N = 225) referred to a low vision rehabilitation clinic for a calendar year were asked a standardised question about symptoms of formed visual hallucinations. Best corrected visual acuity and contrast sensitivity using the Pelli-Robson chart were measured. We conducted multiple logistic regression analysis of the association between visual hallucinations and visual parameters. Results: Of the total cohort, 78 (35%) reported visual hallucinations. Visual acuity and contrast sensitivity were considered in four quartiles. In multiple logistic regression controlling for contrast sensitivity, age, gender, report of depression and independence, measured acuity in each of the poorer three categories (compared to the best) was not associated with reported hallucinations. Contrast sensitivity in the three poorer quartiles (compared to the best) was strongly associated with the report of hallucinations (OR 4.1, CI 1.1, 15.9; OR 10.5, CI 2.6, 42.1; OR 28.1, CI 5.6, 140.9) after controlling for acuity, age, sex, depression and independence. Conclusions: Lowest contrast sensitivity was the strongest predictor of reported hallucinations after adjusting for visual acuity.

Visual outcome of cataract surgery in children with congenital rubella syndrome

PURPOSE To evaluate visual outcome after cataract surgery in children with congenital rubella syndrome (CRS). METHODS A retrospective analysis was conducted on 40 eyes of 22 children with CRS who underwent cataract surgery. Thirty-six eyes underwent lensectomy with anterior vitrectomy, and 4 eyes underwent extracapsular cataract extraction with primary posterior capsulectomy. The median age at surgery was 6 months, and median duration of postoperative follow up was 68.5 months. Each follow-up visit consisted of visual acuity estimation, refraction, anterior and posterior segment examination, and intraocular pressure measurements. RESULTS Visual acuity at final follow up was 6/24 or better in 6 (15.0%) eyes, and 22 (55.0%) eyes had visual acuity less than 3/60. Postoperative complications included transient corneal edema in 18 (45.0%) eyes, glaucoma in 5 (12.5%) eyes, after cataract in 1 (2.5%) eye, and hyphema in 1 (2.5%) eye. Ocular disorders affecting visual outcome included stimulus deprivation amblyopia, glaucoma, optic atrophy, corneal opacity, and after cataract. Associated systemic disorders included neurological problems in 15 (68.2%), hearing loss in 12 (54.6%), cardiovascular problems in 9 (40.9%), and speech abnormalities in 7 (31.8%) children. CONCLUSIONS The less-than-optimal postoperative visual outcome suggests the need to look at primary prevention of rubella, especially in developing countries.

Cataract and its surgery in Papua New Guinea.

Purpose:  To determine the prevalence of visually significant cataract, unoperated blinding cataract, and cataract surgery for those aged 50 years and over in Papua New Guinea. Also, to determine the characteristics, rate, coverage and outcome of cataract surgery, and barriers to its uptake.