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L Dandona

Publications and source records attributed to L Dandona.

At least 55 records · Page 3Linked to original sources
PubMed1998

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

BACKGROUND: India's 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. METHODS: We 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. FINDINGS: 2522 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. INTERPRETATION: Much 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.

Adult↗
PubMed1998

Causes of corneal graft failure in India.

The success of corneal grafting in visual rehabilitation of the corneal blind in India depends on survival of the grafts. Understanding the causes of graft failure may help reduce the risk of failure. We studied these causes in a series of 638 graft failures at our institution. Multivariate logistic regression analysis was used to evaluate the association of particular causes of graft failure with indications for grafting, socioeconomic status, age, sex, host corneal vascularization, donor corneal quality, and experience of surgeon. The major causes of graft failure were allograft rejection (29.2%), increased intraocular pressure (16.9%), infection excluding endophthalmitis (15.4%), and surface problems (12.7%). The odds of infection causing graft failure were significantly higher in patients of lower socioeconomic status (odds ratio 2.45, 95% CI 1.45-4.15). Surface problems as a cause of graft failure was significantly associated with grafts done for corneal scarring or for regrafts (odds ratio 3.36, 95% CI 1.80-6.30). Increased intraocular pressure as a cause of graft failure had significant association with grafts done for aphakic or pseudophakic bullous keratopathy, congenital conditions or glaucoma, or regrafts (odds ratio 2.19, 95% CI 1.25-3.84). Corneal dystrophy was the indication for grafting in 12 of the 13 cases of graft failure due to recurrence of host disease. Surface problems, increased intraocular pressure, and infection are modifiable risk factors that are more likely to cause graft failure in certain categories of patients in India. Knowledge about these associations can be helpful in looking for and aggressively treating these modifiable risk factors in the at-risk categories of corneal graft patients. This can possibly reduce the chance of graft failure.

Child↗
PubMed1998

Economic burden of blindness in India.

Economic analysis is one way to determine the allocation of scarce resources for health-care programs. The initial step in this process is to estimate in economic terms the burden of diseases and the benefit from interventions for prevention and treatment of these diseases. In this paper, the direct and indirect economic loss due to blindness in India is calculated on the basis of certain assumptions. The cost of treating cataract blindness in India is estimated at current prices. The economic burden of blindness in India for the year 1997 based on our assumptions is Rs. 159 billion (US$ 4.4 billion), and the cumulative loss over lifetime of the blind is Rs. 2,787 billion (US$ 77.4 billion). Childhood blindness accounts for 28.7% of this lifetime loss. The cost of treating all cases of cataract blindness in India is Rs. 5.3 billion (US$ 0.15 billion). Similar estimates for causes of blindness other than cataract have to be made in order to develop a comprehensive approach to deal with blindness in India.

Adolescent↗
PubMed1998

Developing a model to reduce blindness in India: The International Centre for Advancement of Rural Eye Care.

With the continuing high magnitude of blindness in India, fresh approaches are needed to effectively deal with this burden on society. The International Centre for Advancement of Rural Eye Care (ICARE) has been established at the L.V. Prasad Eye Institute in Hyderabad to develop such an approach. This paper describes how ICARE functions to meet its objective. The three major functions of ICARE are design and implementation of rural eye-care centres, human resource development for eye care, and community eye-health planning. ICARE works with existing eye-care centres, as well as those being planned, in underserved areas of India and other parts of the developing world. The approach being developed by ICARE, along with its partners, to reduce blindness is that of comprehensive eye care with due emphasis on preventive, curative and rehabilitative aspects. This approach involves the community in which blindness is sought to be reduced by understanding how the people perceive eye health and the barriers to eye care, thereby enabling development of strategies to prevent blindness. Emphasis is placed on providing good-quality eye care with attention to reasonable infrastructure and equipment, developing a resource of adequately trained eye-care professionals of all cadres, developing a professional environment satisfactory for patients as well as eye-care providers, and the concept of good management and financial self-sustainability. Community-based rehabilitation of those with incurable blindness is also part of this approach. ICARE plans to work intensively with its partners and develop these concepts further, thereby effectively bringing into practice the concept of comprehensive eye care for the community in underserved parts of India, and later in other parts of the developing world. In addition, ICARE is involved in assessing the current situation regarding the various aspects of blindness through well-designed epidemiologic studies, and projecting the eye-care needs for the future with the help of reliable information. With balanced attention to infrastructure, manpower, financial self-sustenance, and future planning, ICARE intends to develop a practical model to effectively reduce blindness in India on a long-term basis.

Blindness↗
PubMed1998

Statistical analysis: the need, the concept, and the usage.

In general, better understanding of the need and usage of statistics would benefit the medical community in India. This paper explains why statistical analysis is needed, and what is the conceptual basis for it. Ophthalmic data are used as examples. The concept of sampling variation is explained to further corroborate the need for statistical analysis in medical research. Statistical estimation and testing of hypothesis which form the major components of statistical inference are construed. Commonly reported univariate and multivariate statistical tests are explained in order to equip the ophthalmologist with basic knowledge of statistics for better understanding of research data. It is felt that this understanding would facilitate well designed investigations ultimately leading to higher quality practice of ophthalmology in our country.

Data Interpretation, Statistical↗
PubMed1998

A method of scoring automated visual fields to determine field constriction causing blindness.

Blindness is usually defined by visual acuity criteria. Patients with markedly constricted visual fields are visually impaired even if they have good visual acuity. To our knowledge, no standardised criteria exist to determine the extent of constriction for fields done with the currently used automated static perimetry. The purpose of this study was to suggest a simple method to do so which would help in determining blindness due to field constriction. We reviewed a number of constricted visual fields obtained with Humphrey automated static perimetry. The central 30 degrees field was divided into six concentric zones. By trial and error, we devised criteria for defining visual field constriction based on absolute loss of sensitivity (< or = 0 dB) and relative loss of sensitivity (< or = 5 dB). We suggest that if a zone has at least 75% test points < or = 0 dB and no point > 10 dB, it be considered to have absolute loss of sensitivity for the purpose of defining visual field blindness. Two exceptions to this are also suggested to prevent this criterion from becoming too rigid. Examples are shown to demonstrate application of these criteria in defining blindness due to visual field constriction to < 10 degrees as suggested by the World Health Organization. Standardised determination of visual field constriction with automated perimetry could be useful in more accurate estimation of blindness in surveys, as well as in assessing eligibility for being classified as blind for legal benefits.

Blindness↗
PubMed1998

Planning to reduce childhood blindness in India.

Reduction of blindness in children assumes particular significance since a blind child suffers from more blind-years than a blind adult. Estimates of the number of children blind in India and the causes of blindness are relatively crude as there are little reliable epidemiologic data. As a result of this, there is no organised approach to the control of childhood blindness in India. In order to address this issue, a workshop on childhood blindness was held at the L.V. Prasad Eye Institute, Hyderabad in November 1996. The aim of this workshop was to review available data, consider possible strategies, and make recommendations concerning the control of childhood blindness in India. These recommendations along with background information about childhood blindness are presented in this paper.

Adolescent↗
PubMed1997

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.

Adolescent↗
PubMed1997

Indications for penetrating keratoplasty in India.

Indications for penetrating keratoplasty (PK) in the developing world from a large series are not well documented. This study was done to evaluate the indications for PK in a major eye care institution in India. The records for a consecutive series of 1,964 PKs were analysed and multiple logistic regression was used to study the effect of age, socioeconomic status and sex on the indications for PK. The indications for PK were corneal scarring in 551 (28.1%) including adherent leukoma in 147 (7.5%), regrafts in 336 (17.1%), active infectious keratitis in 239 (12.2%), aphakic bullous keratopathy in 231 (11.8%), pseudophakic bullous keratopathy in 209 (10.6%), corneal dystrophies in 165 (8.4%) including Fuchs' dystrophy in 23 (1.2%), keratoconus in 118 (6%), and miscellaneous in 115 (5.9%). The odds that the patient belonged to lower socioeconomic status were significantly higher if the PK was done for active infectious keratitis (odds ratio 2.73, p < 0.0001), corneal scarring (odds ratio 1.72, p = 0.0009) or regraft (odds ratio 1.44, p = 0.047). Corneal scarring, including adherent leukoma, and active infectious keratitis are relatively more common indications whereas keratoconus, pseudophakic bullous keratopathy and Fuchs' dystrophy are less common indications for PK in India than reported from the developed world. Indications for PK which carry a poorer prognosis for graft survival are relatively more common in India than in the developed world.

Adolescent↗
PubMed1997

Visual impairment in school children in southern India.

This study was done to determine the prevalence of visual impairment due to refractive errors and ocular diseases in lower middle class school children of Hyderabad, India. A total of 4,029 children, which included 2,348 males and 1,681 females, in the age range of 3 to 18 years from 9 schools were screened with a detailed ocular examination protocol. Among 3,669 children in whom visual acuity could be recorded, on presentation 115 (3.1%) had visual acuity < 6/18 in the better eye (equivalent to visual impairment), while 41 (1.1%) had visual acuity < or = 6/60 [corrected] in the better eye (equivalent to legal blindness) out of which 18 (0.5%) had visual acuity < 6/60 in the better eye (equivalent to economic blindness). Of 115 children who presented with initial visual acuity < 6/18, vision improved to > or = 6/18 with refraction in 109 (94.8%). No child was legally or economically blind after refractive correction. Prevalence of hyperopia was 22.6%, myopia 8.6% and astigmatism 10.3%. The prevalence of myopia was significantly higher among children > or = 10 years of age (P < 0.001). The maximum, mean and median values for myopia were 10.00, 1.35 and 0.75 D in the better eye. For hyperopia these values were 8.50, 0.65 and 0.50 D. The major causes for best corrected visual acuity < 6/9 in the worse eye for 51 (1.4%) children included amblyopia in 40 (1.1%), corneal diseases in 5 (0.1%), cataract in 2 (0.05%) and others in 4 (0.1%). Out of the total, 30 (0.7%) children had strabismus. These data support the assumption that vision screening of school children in developing countries could be useful in detecting correctable causes of decreased vision, especially refractive errors, and in minimising long term permanent visual disability.

Adolescent↗
PubMed1997

Design of a population-based study of visual impairment in India: The Andhra Pradesh Eye Disease Study.

Reliable population-based epidemiologic data regarding vision and ocular morbidity, as well as those about the perceptions of people regarding visual impairment and eye care, are lacking for the most part in the developing world including India. These data are the basis on which effective eye care services can be developed. To meet this need we designed the Andhra Pradesh Eye Disease Study, a population-based epidemiology study of 10,000 people in the Indian state of Andhra Pradesh. The design of this study is described in this paper. Various options for the sample size, study areas, sampling procedure, and recruitment of subjects were considered. A sample size of 10,000 people, 5,000 each in the < or = 30 and > 30 years age groups, was determined to obtain reasonable confidence in estimating the prevalence of diseases and odds ratios for risk factors of interest. A multistage sampling strategy was chosen for the study which was assumed to give a design effect of 1.5 for the estimates. One urban area, Hyderabad, and three rural areas, West Godavari, Adilabad and Mahbubnagar districts, were selected in Andhra Pradesh. Interview instruments were developed to obtain detailed information about demographic data, diet, ocular and systemic history, risk factors for eye diseases, visual function, quality of life, barriers to eye care, and knowledge about eye diseases. A detailed examination procedure was devised to obtain a broad range of normative and abnormal data related to eyes and vision. A protocol was developed for doing automated visual fields, slitlamp and fundus photography. Computer databases were made in FoxPro for data entry and subsequent analysis with SPSS. Pilot studies were done to test the instruments, procedures, and logistics of the study in urban and rural areas. Information from the Andhra Pradesh Eye Disease Study is expected to help in planning and implementation of effective long-term preventive, curative, and rehabilitative eye care services in Andhra Pradesh.

Blindness↗
PubMed1993

Laser photocoagulation of experimental corneal stromal vascularization. Efficacy and histopathology.

BACKGROUND: Conventional treatment of corneal stromal vascularization is often inadequate. The authors developed a rabbit model of corneal stromal vascularization, treated it with laser photocoagulation, and then studied the histopathology. METHODS: A reproducible model of corneal stromal vascularization was developed in albino rabbits by injecting sodium hydroxide into the corneal stroma. Corneal stromal vascularization was produced in both eyes of 13 rabbits, and treated after stabilization at 5 weeks with 577-nm yellow dye laser in 1 eye of each rabbit. Seven rabbits were followed for 6 months with corneal angiography and photography, and the corneal stromal vascularization quantified with a grid. The other 6 rabbits were killed at 1, 4, 8, 24, 48 hours, and 6 days after laser photocoagulation and examined by light and transmission electron microscopy. RESULTS: Stable corneal stromal vascularization was observed in the anterior and midstroma for at least 6 months in the model. Laser photocoagulation reduced corneal stromal vascularization significantly compared with the controls (P < or = 0.05), resulting in 40.7% +/- 5.0%, 45.3% +/- 3.3%, and 34.9% +/- 5.2% (mean +/- standard error of the mean) reduction at 2, 4, and 6 months, respectively. Maximum inflammatory cell infiltrates were detected at 8 hours after laser photocoagulation, which diminished markedly at 6 days. The stroma of unlasered eyes showed no inflammatory cells and considerably more patent blood vessels than the lasered eyes. In the lasered eyes, transmission electron microscopy showed damaged vascular endothelial cells, extravasated erythrocytes, haphazardly arranged collagen fibrils, thrombus formation, and ghost vessels in the stroma. No damage was observed in the deep corneal stroma or endothelium in the lasered eyes. CONCLUSION: Laser photocoagulation is effective in reducing corneal stromal vascularization in this model for at least 6 months. It does not damage the deeper stroma or endothelium.

Animals↗
PubMed1991

Selective effects of experimental glaucoma on axonal transport by retinal ganglion cells to the dorsal lateral geniculate nucleus.

Rapid-phase axonal transport to the dorsal lateral geniculate nucleus (dLGN) was determined autoradiographically in seven macaque monkey eyes with chronic intraocular pressure (IOP) elevation, in four eyes with an acute IOP elevation, and in three eyes with normal IOP. The monkeys with chronic IOP elevation showed a greater decrease in radioactive labeling of the magnocellular layers of the dLGN than the parvocellular layers by qualitative examination. Grain counts in selected specimens confirmed that transport to the magnocellular layers was less than to the parvocellular layers in monkeys with chronic IOP elevation. This selectivity was present in mildly damaged specimens and increased with greater ganglion cell loss. In monkeys with acute IOP elevation, qualitative evaluation suggested no consistent difference in transport among the dLGN layers; one animal in this group had less transport to the parvocellular than to the magnocellular layers by grain counts. Starting in early stages of the disease, chronic experimental glaucoma causes preferential damage to the ganglion cells that project to the magnocellular layers of the dLGN.

Animals↗
PubMed1990

Quantitative regional structure of the normal human lamina cribrosa. A racial comparison.

We digitized magnified photographs of cross-sections of the laminae cribrosae of 16 normal subjects 50 or more years of age. The sample included 7 blacks and 9 age-matched whites. Connective tissue area as a proportion of the lamina cribrosa area was significantly less and pores were significantly larger in the superior and inferior than in the nasal and temporal quadrants of the lamina cribrosa. These differences were more pronounced for peripheral as compared with central regions of the lamina cribrosa. Less connective tissue support for nerve fibers in the superior and inferior quadrants of the optic nerve head could contribute to their greater susceptibility to glaucoma damage by allowing greater distortion of these regions at elevated intraocular pressures. The least connective tissue support was present in the inferoperipheral region of the lamina cribrosa, which may be related to the greater frequency of superior visual field defects in glaucoma. Blacks had larger total lamina cribrosa area, indicating a larger optic nerve head, and also a greater number of laminar pores than whites. However, the connective tissue proportion and pore size distribution in the laminae cribrosae of blacks were almost identical to those of whites. We found no evidence suggesting that the greater susceptibility of blacks to glaucoma damage is due to less connective tissue support for nerve fibers passing through their laminae cribrosae than in whites.

Aged↗