Lalit Dandona

Angle-closure glaucoma in an urban population in southern india: The andhra pradesh eye disease study

OBJECTIVEnTo assess the prevalence and features of angle-closure glaucoma (ACG) in an urban population in southern India.nnnDESIGNnA population-based, cross-sectional study.nnnPARTICIPANTSnA total of 2522 (85.4% of those eligible) persons of all ages, including 1399 persons 30 years of age or older, from 24 clusters representative of the population of Hyderabad city.nnnTESTINGnThe participants underwent an interview and detailed eye examination that included logarithm of minimum angle of resolution visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, and gonioscopy; pupil dilatation and stereoscopic fundus evaluation was performed if the risk of angle-closure as a result of dilatation was not believed to be imminent. Humphrey threshold 24-2 visual fields (Humphrey Instruments Inc., San Leandro, CA) were performed when indicated by standardized criteria for disc damage or if intraocular pressure (IOP) was 22 mmHg or more.nnnMAIN OUTCOME MEASURESnAn occludable angle was defined as pigmented posterior trabecular meshwork not visible by gonioscopy in three quarters or more of the angle circumference. Manifest primary angle-closure glaucoma (PACG) was defined as IOP of 22 mmHg or more or glaucomatous optic disc damage with visual field loss in the presence of an occludable angle. An IOP of 22 mmHg or more or glaucomatous optic disc damage in the presence of an occludable angle secondary to an obvious cause was defined as secondary ACG.nnnRESULTSnManifest PACG and occludable angles without ACG were present in 12 and 24 participants, respectively, with age- and gender-adjusted prevalence (95% confidence interval [CI]) of 0.71% (0.34%-1.31%) and 1.41% (0.73%-2.09%) in participants 30 years of age or older, and 1.08% (0.36%-1.80%) and 2.21% (1.15%-3.27%) in participants 40 years of age or older, respectively. With multivariate analysis, the prevalence of these two conditions considered together increased significantly with age (P < 0.001); although not statistically significant, these were more common in females (odds ratio 1.70; 95% CI, 0.82-3.54) and in those belonging to lower socioeconomic strata as compared with middle and upper strata (odds ratio, 1.82; 95% CI, 0.88-3.74). The odds of manifest PACG were higher in the presence of hyperopia of more than 2 diopters ([D]; odds ratio, 3.69; 95% CI, 0.89-15.2). Only four of 12 participants (33.3%) with manifest PACG had been previously diagnosed, and one of 12 (8.3%) had peripheral iridotomy performed previously. Manifest PACG had caused blindness in one or both eyes in five of these 12 participants (41.7%); best-corrected distance visual acuity less than 20/400 in one or both eyes in four patients, and acuity less than 20/200 in one eye in another patient. Most (83.3%) of those with manifest PACG could be classified as having chronic form of the disease. We may have underestimated manifest PACG because visual fields were per- formed only on those with clinical suspicion of optic disc damage. Secondary ACG was present in two participants.nnnCONCLUSIONSnThe prevalence of PACG in this urban population in southern India is close to that reported recently in a Mongolian population. A large proportion of the PACG in this population was undiagnosed and untreated. Because visual loss resulting from PACG is potentially preventable if peripheral iridotomy or iridectomy is performed in the early stage, strategies for early detection of PACG could reduce the high risk of blindness resulting from PACG seen in this urban population in India.

Open-angle glaucoma in an urban population in southern india: The andhra pradesh eye disease study

OBJECTIVEnTo assess the prevalence and features of open-angle glaucoma in an urban population in southern India.nnnDESIGNnA population-based cross-sectional study.nnnPARTICIPANTSnA total of 2522 persons (85.4% of those eligible) of all ages, including 1399 persons 30 years of age or older, from 24 clusters representative of the population of Hyderabad city.nnnTESTINGnThe participants underwent an interview and detailed eye examination that included logarithm of minimum angle of resolution visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, dilatation, cataract grading, and stereoscopic fundus evaluation. Automated Humphrey threshold 24-2 visual fields (Humphrey Instruments Inc., San Leandro, CA) and optic disc photography were performed when indicated by standardized criteria for disc damage or if intraocular pressure (IOP) was 22 mmHg or more.nnnMAIN OUTCOME MEASURESnDefinite primary open-angle glaucoma (POAG) was defined as obvious glaucomatous optic disc damage and visual field loss in the presence of an open-angle, and suspected POAG was defined as suspected glaucomatous optic disc damage without definite visual field loss. Ocular hypertension (OHT) was defined as IOP of 22 mmHg or more without glaucomatous optic disc damage or visual field loss in the presence of an open-angle. Glaucomatous optic disc damage or IOP of 22 mmHg or more secondary to an obvious cause and with an open-angle was defined as secondary open-angle glaucoma.nnnRESULTSnDefinite POAG, suspected POAG, and OHT were present in 27, 14, and 7 participants, respectively, with age- and gender-adjusted prevalence (95% confidence interval) of 1.62% (0.77%-2.48%), 0.79% (0.39%-1.41%), and 0.32% (0.10%-0.78%) in those 30 years of age or older, and 2.56% (1.22%-3.91%), 1.11% (0.43%-1.78%), and 0.42% (0.11%-1.12%) in those 40 years of age or older, respectively. The prevalence of POAG increased significantly with age using multivariate analysis (P < 0.001). Only two of 27 participants (7.4%) with definite POAG had been previously diagnosed and treated, and 66.7% of the previously undiagnosed had IOP less than 22 mmHg. Fourteen of 27 participants (51.9%) with definite POAG had severe glaucomatous damage based on optic disc and visual field criteria, of which five participants (18.5%) had at least one blind eye as a result of POAG (all with best-corrected distance visual acuity less than 20/400 or central visual field less than 10 degrees); the other 13 participants (48.1%) had moderate glaucomatous damage. Because visual fields and optic disc photography were not performed on all participants, the prevalence of POAG may have been underestimated. Secondary open-angle glaucoma was present in one participant as a result of angle recession.nnnCONCLUSIONSnThe prevalence of open-angle glaucoma in this urban population in southern India is at least as much as that reported recently from white populations in developed countries. However, the vast majority of persons with glaucoma were undiagnosed in this population, and a large proportion of those having definite POAG already had severe glaucomatous damage.

Is current eye-care-policy focus almost exclusively on cataract adequate to deal with blindness in India?

BACKGROUNDnIndias National Programme for Control of Blindness focuses almost exclusively on cataract, based on a national survey done in the 1980s which reported that cataract caused 80% of the blindness in India. No current population-based data on the causes of blindness in India are available. We assessed the rate and causes of blindness in an urban population in southern India.nnnMETHODSnWe selected 2954 participants by stratified, random, cluster, systematic sampling from Hyderabad city. Eligible participants were interviewed and given a detailed ocular assessment, including visual acuity, refraction, slitlamp biomicroscopy, applanation intraocular pressure, gonioscopy, dilatation, grading of cataract, stereoscopic fundus assessment, and automated-threshold visual fields.nnnFINDINGSn2522 participants, including 1399 aged 30 years or more, were assessed. 49 participants (all aged > or =30 years) were blind (presenting distance visual acuity <6/60 or central visual field <200 in the better eye). The rate of blindness among those aged 30 years or more, adjusted for age and sex, was 3.08% ([95% CI 1.95-4.21]). Causes included cataract (29.7%), retinal disease (17.1%), corneal disease (15.4%), refractive error (12.5%), glaucoma (12.1%), and optic atrophy (11.0%). 15.7% of the blindness caused by visual-field constriction would have been missed without visual-field examination. Also without visual-field and detailed dilated-fundus assessments, blindness attributed to cataract would have been overestimated by up to 75.8%. If the use of cataract surgery in this urban population was half that found in this study, which simulates the situation in rural India, cataract would have caused 51.8% (39.4-64.2) of blindness, significantly less than the 80% accepted by current policy.nnnINTERPRETATIONnMuch of the blindness in this Indian population was due to non-cataract causes. The previous national survey did not include detailed dilated-fundus assessment and visual-field examination which could have led to overestimation of cataract as a cause of blindness in India. Policy-makers in India should encourage well-designed population-based epidemiological studies from which to develop a comprehensive long-term policy on blindness in addition to dealing with cataract.

Population-based assessment of the outcome of cataract surgery in an urban population in southern India

PURPOSEnTo assess the outcome of cataract surgery in an urban population in southern India.nnnMETHODSnAs part of a population-based cross-sectional epidemiologic study, the Andhra Pradesh Eye Disease Study, 2,522 people of all ages, including 1,399 individuals 30 years of age or older, from 24 clusters representative of the population of Hyderabad in southern India underwent a detailed interview and ocular evaluation including logarithm of minimal angle of resolution (logMAR) visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, dilation, cataract grading, aphakia/pseudophakia status, and stereoscopic fundus evaluation. Automated threshold visual fields and slit-lamp and fundus photography were performed when indicated by standardized criteria. Very poor outcome in an eye that had undergone cataract surgery was defined as presenting distance visual acuity worse than 20/200, and poor outcome was defined as visual acuity worse than 20/60 to 20/200.nnnRESULTSnIn subjects 50 years of age or older, after adjustment for age and sex distribution, the rate of having had cataract surgery in one or both eyes was 14.6% (95% confidence interval [CI], 11.4% to 17.8%). Of 131 eyes (91 subjects) that had undergone cataract surgery, 28 (21.4%; 95% CI, 14.4% to 28.4%) had very poor outcome and another 40 (30.5%; 95% CI, 22.6% to 38.4%) had poor outcome. The very poor outcome in 20 (71.4%) of 28 eyes and poor outcome in 23 (57.5%) of 40 eyes could be attributed to surgery-related causes or inadequate refractive correction. With multivariate analysis, very poor outcome as a result of surgery-related causes or inadequate refractive correction was more likely to be associated with intracapsular cataract extraction than with extracapsular cataract extraction (odds ratio, 9.34; 95% CI, 2.49 to 35.06) in subjects belonging to the lowest socioeconomic status (odds ratio, 4.92; 95% CI, 1.16 to 20.93) and with date of surgery 3 or fewer years before the survey than with more than 3 years (odds ratio, 4.52; 95% CI, 1.33 to 15.39). Also, very poor or poor outcome as a result of surgery-related causes or inadequate refractive correction was associated with women (odds ratio, 2.55; 95% CI, 1.06 to 6.16).nnnCONCLUSIONSnThe very high rate of very poor and poor visual outcome, predominantly as a result of surgery-related causes and inadequate refractive correction, in this urban population of India suggests that more attention is needed to improve the visual outcome of cataract surgery. In order to deal with cataract-related visual impairment in India, as much emphasis on surgical quality, refractive correction, and follow-up care is necessary as on the number of surgeries.

Survival analysis and visual outcome in a large series of corneal transplants in India

AIM/BACKGROUND The public health significance of corneal transplantation in dealing with corneal blindness in the developing world would depend upon the survival rate of transplants. This study was done to analyse the survival rate of corneal transplants in a large series in India, and to evaluate the influence of various risk factors on transplant survival. METHODS The records of a series of 1725 cases of corneal transplants carried out during 1987–95 at a tertiary eye care institution in India were reviewed. The Kaplan–Meier method was used to determine 5 year survival rates of corneal transplants performed for the various categories of preoperative diagnosis. Multivariate Cox proportional hazards regression was used to assess how preoperative diagnosis, socioeconomic status, age, sex, vascularisation of host cornea, quality of donor cornea, and training status of surgeon influenced transplant survival. The effect of these variables on visual outcome was assessed using multiple logistic regression. RESULTS The survival rates at 1, 2, and 5 years for all corneal transplants performed for the first time in 1389 cases were 79.6% (95% confidence interval = 77.3–81.9%), 68.7% (65.7–71.7%) and 46.5% (41.7–51.3%). The 5 year survival rate was highest if the corneal transplant was done for keratoconus (95.1% (84.8–100%)) and lowest if carried out for previous transplant failure (21.2% (13.8–28.6%)). The relative risk of transplant failure was higher if the preoperative diagnosis was previous transplant failure (2.04 (1.62–2.55)), aphakic bullous keratopathy (1.78 (1.38–2.28)), corneal clouding due to miscellaneous causes including congenital conditions and glaucoma (1.63 (1.21–2.19)), or adherent leucoma (1.11 (0.81–1.51)) than for the other preoperative diagnoses. Patients with lower socioeconomic status had higher relative risk of transplant failure (1.28 (1.16–1.42)), as did patients <10 years of age (1.42 (1.23–1.64)). Higher relative risk of transplant failure was associated with vascularisation of the host cornea before transplantation (1.15 (1.04–1.27)), and with the use of fair quality donor cornea for transplantation compared with excellent, very good, or good quality donor cornea (1.26 (1.06–1.52)). Before corneal transplant 80.2% of the eyes were blind (visual acuity <3/60), whereas at last follow up 41.8% eyes were blind. The odds of having visual acuity >6/18 were higher if the transplant was done for keratoconus (9.99 (6.10–16.36)) or corneal dystrophies (1.77 (1.21–2.58)) than for the other preoperative diagnoses. CONCLUSION Reasonable success with corneal transplantation is possible in the developing world if data from this part of the world regarding the different survival rates for the various preoperative diagnoses and the influence of risk factors on transplant survival and visual outcome are taken into account while determining priority for transplant cases in the present situation of limited availability of donor corneas.

Awareness of eye diseases in an urban population in southern India

OBJECTIVEnTo assess the level of awareness of eye diseases in the urban population of Hyderabad in southern India.nnnMETHODSnA total of 2522 subjects of all ages, who were representative of the Hyderabad population, participated in the population-based Andhra Pradesh Eye Disease Study. Of these subjects, 1859 aged > 15 years responded to a structured questionnaire on cataract, glaucoma, night blindness and diabetic retinopathy to trained field investigators. Having heard of the eye disease in question was defined as awareness and having some understanding of the eye disease was defined as knowledge.nnnFINDINGSnAwareness of cataract (69.8%) and night blindness (60.0%) was moderate but that of diabetic retinopathy (27.0%) was low, while that of glaucoma (2.3%) was very poor. Knowledge of all the eye diseases assessed was poor. Subjects aged > or = 30 years were significantly more aware of all eye diseases assessed except night blindness. Multivariate analysis revealed that women were significantly less aware of night blindness (odds ratio (OR) = 0.78; 95% confidence interval (CI) = 0.63-0.97). Education played a significant role in awareness of these eye diseases. Study subjects of upper socioeconomic status were significantly more aware of night blindness (OR = 2.20; 95% CI = 1.29-3.74) and those belonging to upper and middle socioeconomic strata were significantly more aware of diabetic retinopathy (OR = 2.79; 95% CI = 2.19-3.56). Muslims were significantly more aware of cataract (OR = 2.36; 95% CI = 1.84-3.02) and less aware of night blindness (OR = 0.52; 95% CI = 0.42-0.64). The major source of awareness of the eye diseases was a family member/friend/relative suffering from that eye disease.nnnCONCLUSIONnThese data suggest that there is a need for health education in this Indian population to increase their level of awareness and knowledge of common eye diseases. Such awareness and knowledge could lead to better understanding and acceptance of the importance of routine eye examinations for the early detection and treatment of eye diseases, thereby reducing visual impairment in this population.

Burden of moderate visual impairment in an urban population in southern India.

OBJECTIVEnTo assess the prevalence and causes of moderate visual impairment in an urban population in southern India.nnnDESIGNnPopulation-based, cross-sectional study.nnnPARTICIPANTSnA total of 2522 (85.4% of the eligible) persons of all ages, including 1399 persons 30 years of age or older, from 24 clusters representative of the population of Hyderabad city.nnnTESTINGnThe eligible subjects underwent a detailed ocular evaluation, including logarithm of the minimum angle of resolution (logMAR) visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, cataract grading, and stereoscopic dilated fundus evaluation. Automated threshold visual fields and slit-lamp and fundus photography were done when indicated by standardized criteria.nnnMAIN OUTCOME MEASUREnModerate visual impairment was defined as presenting distance visual acuity less than 20/40 to 20/200 or visual field loss by predefined standardized conservative criteria in the better eye.nnnRESULTSnIn addition to the 1% prevalence of blindness in this sample reported earlier, moderate visual impairment was present in 303 subjects, an age-gender-adjusted prevalence of 7.2% (95% confidence interval [CI], 4.5%-9.9%; design effect, 2.7). The major cause of moderate visual impairment was refractive error (59.4%, 95% CI, 52.3%-66.5%) followed by cataract (25.3%, 95% CI, 19%-31.6%). Multivariate analysis showed that the prevalence of moderate visual impairment was significantly higher in those 40 years of age or older (odds ratio, 10.9; 95% CI, 8-15) and females (odds ratio, 1.89; 95% CI, 1.41-2.53) and lower in those belonging to the highest socioeconomic status (odds ratio, 0.27; 95% CI, 0.14-0.51). However, because of the pyramidal age distribution of the population, 38.1% of the total moderate visual impairment was present in those younger than 40 years of age. The proportion of moderate visual impairment caused by refractive error was higher in the younger than in the older age groups (P < 0.0001).nnnCONCLUSIONSnProjecting the results to the 26.5% urban population of India, there would be 18.4 million (95% CI, 11.5-25.2 million) persons with moderate visual impairment in urban India alone. Refractive error was the major cause of moderate visual impairment in the population studied. The absolute proportion of moderate visual impairment in those younger than 40 years of age was considerable. The eyecare policy of India, apart from dealing with blindness, should address the issue of the relatively easily treatable uncorrected refractive error as the cause of moderate visual impairment in an estimated 10.9 million persons in urban India.

Moderate visual impairment in India: the Andhra Pradesh Eye Disease Study

Aim: To assess the prevalence and demographic associations of moderate visual impairment in the population of the southern Indian state of Andhra Pradesh. Methods: From 94 clusters in one urban and three rural areas of Andhra Pradesh, 11 786 people of all ages were sampled using a stratified, random, cluster, systematic sampling strategy. The eligible people were invited for interview and detailed dilated eye examination by trained professionals. Moderate visual impairment was defined as presenting distance visual acuity less than 6/18 to 6/60 or equivalent visual field loss in the better eye. Results: Of those sampled, 10 293 (87.3%) people participated in the study. In addition to the previously reported 1.84% prevalence of blindness (presenting distance visual acuity less than 6/60 or central visual field less than 20° in the better eye) in this sample, 1237 people had moderate visual impairment, an adjusted prevalence of 8.09% (95% CI 6.89 to 9.30%). The majority of this moderate visual impairment was caused by refractive error (45.8%) and cataract (39.9%). Increasing age, female sex, decreasing socioeconomic status, and rural area of residence had significantly higher odds of being associated with moderate visual impairment. Conclusions: These data suggest that there is a significant burden of moderate visual impairment in this population in addition to blindness. Extrapolation of these data to the population of India suggests that there were 82 million people with moderate visual impairment in the year 2000, and this number is likely to be 139 million by the year 2020 if the current trend continues. This impending large burden of moderate visual impairment, the majority of which is due to the relatively easily treatable refractive error and cataract, would have to be taken into account while estimating the eye care needs in India, in addition to dealing with blindness. Specific strategies targeting the elderly population, people with low socioeconomic status, those living in the rural areas, and females would have to be implemented in the long term to reduce moderate visual impairment.

Visual acuity in Children with coloboma : Clinical features and a new phenotypic classification system

OBJECTIVEnThe aims of this study were to describe the clinical features and biometric findings in the eyes of children with coloboma and to develop a classification of coloboma that correlates with visual function.nnnDESIGNnRetrospective observational case series.nnnPARTICIPANTSnOne hundred thirteen children and young adults (48 female, 65 male) aged 0 to 20 years with 196 eyes having coloboma.nnnMETHODSnChildren with coloboma were recruited from schools for the blind, integrated education programs, schools for the mentally handicapped, community-based rehabilitation services, and hospital clinics in Andhra Pradesh, India, between January 1998 and January 1999. Visual function was assessed, including distance and near visual acuity (VA), and navigational vision. The corneal diameter and axial length of eyes were measured wherever possible.nnnMAIN OUTCOME MEASURESnAnatomic site of coloboma, association with microcornea and/or microphthalmos, VA, presence of navigational vision and reading vision.nnnRESULTSnOf 196 eyes with colobomatous malformations, 11 had microphthalmos with cyst, and 185 eyes had coloboma (associated with microcornea in 155 eyes and with a normal corneal diameter in 30). Microphthalmos was present in 72 of the 185 eyes with coloboma, of which 71 of 72 also had microcornea. The prognosis for vision depended on the phenotype of the better eye. Microphthalmos with cyst had the worst prognosis (VA < 3/60, 100%; reading and navigational vision, 0%). Microcornea with microphthalmos had a worse prognosis than microcornea without microphthalmos (VA < 3/60: 66.7% vs. 23.3%; unable to read N10: 66.7% vs. 34.1 %; no navigational vision: 30.6% vs. 6.73%). Simple coloboma (no microcornea or microphthalmos) had the best prognosis (VA < 3/60: 6.7%; able to read N10: 93.3%; navigational vision: 100%). A corneal diameter <6 mm had a poor visual prognosis, whereas a corneal diameter >10 mm had a good prognosis.nnnCONCLUSIONSnA phenotypic classification of coloboma is proposed, which in this study showed a good correlation with visual acuity, reading, and navigational vision. Microphthalmos with cyst had the worst prognosis, coloboma with microcornea and microphthalmos a poor prognosis, coloboma with only microcornea had an intermediate prognosis, and simple coloboma had the best prognosis.Abstract Objective The aims of this study were to describe the clinical features and biometric findings in the eyes of children with coloboma and to develop a classification of coloboma that correlates with visual function. Design Retrospective observational case series. Participants One hundred thirteen children and young adults (48 female, 65 male) aged 0 to 20 years with 196 eyes having coloboma. Methods Children with coloboma were recruited from schools for the blind, integrated education programs, schools for the mentally handicapped, community-based rehabilitation services, and hospital clinics in Andhra Pradesh, India, between January 1998 and January 1999. Visual function was assessed, including distance and near visual acuity (VA), and navigational vision. The corneal diameter and axial length of eyes were measured wherever possible. Main outcome measures Anatomic site of coloboma, association with microcornea and/or microphthalmos, VA, presence of navigational vision and reading vision. Results Of 196 eyes with colobomatous malformations, 11 had microphthalmos with cyst, and 185 eyes had coloboma (associated with microcornea in 155 eyes and with a normal corneal diameter in 30). Microphthalmos was present in 72 of the 185 eyes with coloboma, of which 71 of 72 also had microcornea. The prognosis for vision depended on the phenotype of the better eye. Microphthalmos with cyst had the worst prognosis (VA 10 mm had a good prognosis. Conclusions A phenotypic classification of coloboma is proposed, which in this study showed a good correlation with visual acuity, reading, and navigational vision. Microphthalmos with cyst had the worst prognosis, coloboma with microcornea and microphthalmos a poor prognosis, coloboma with only microcornea had an intermediate prognosis, and simple coloboma had the best prognosis.

Regional variation in blindness in children due to microphthalmos, anophthalmos and coloboma

BACKGROUND. The prevalence and causes of blindness in children vary widely between regions. Few epidemiological data are available on the relative importance of the major congenital anomalies of the globe (i.e., microphthalmos, anophthalmos, coloboma) as causes of blindness in children. The aim of this study was to determine the re-gional variation in the proportion of severe visual impairment and blindness due to congenital abnormalities of the globe in children in schools for the blind and in those identified through Community Based Rehabilitation programs. Other objectives were to estimate the prevalence of blindness due to major congenital abnormalities, and to investigate their etiology. METHODS. Data on the causes of blindness in children were collected between 1990 and 1998 using standard methods, definitions and reporting form in 26 countries. Children were examined in schools for the blind and in Community Based Rehabilitation programs. RESULTS. Of 7,113 children aged 3-15 years with severe visual impairment and blindness examined, 762 (10.7%) had microphthalmos, 161 (2.3%) had anophthalmos, and 96 (1.3%) had coloboma. There are large regional differences in the proportion of severe visual loss in blind school children, ranging from 1.4% in Cuba to 33.2% in Sri Lanka. Severe visual loss due to congenital abnormalities of the globe is estimated to affect between 0.4 and 16.2/100,000 children in the countries studied. An underlying cause could not be identified in 84.2%. CONCLUSIONS. Major congenital abnormalities of the globe are important causes of severe visual loss in children, particularly in Asian countries. Further research into etiology is warranted in order to plan prevention programs.