|Year : 2022 | Volume
| Issue : 2 | Page : 123-129
Etiology of permanent visual impairment among persons attending a disability board in Central Kerala
Sinumol Sukumaran1, Nandini Varma1, N Sujatha1, T Devu Krishna2
1 Department of Ophthalmology, Government Medical College, Thrissur, Kerala, India
2 Department of Ophthalmology, Kasturba Medical College, Mangaluru, Karnataka, India
|Date of Submission||22-Oct-2021|
|Date of Decision||06-Mar-2022|
|Date of Acceptance||14-Mar-2022|
|Date of Web Publication||30-Aug-2022|
Dr. T Devu Krishna
Adwaitham, Green Lane, M G Kavu P O, Thrissur, Kerala
Source of Support: None, Conflict of Interest: None
Introduction: Permanent visual handicap is one of the most troublesome disabilities to affect an individual, a family, and a society. Objectives: To determine the important etiological factors leading to permanent visual impairment (VI) in Kerala and their frequency trends over the recent years. Materials and Methods: Retrospective study of case records of the medical board of a government medical college hospital in Kerala from 2017 to 2020. Inclusion Criteria: Data of all individuals with permanent VI of categories 1 to 4. Exclusion Criteria: Category zero of permanent disability. The guidelines included under the Rights of Persons with Disabilities Act, 2016 were followed for assessing the extent of visual disability. The age, gender, place, diagnosis in the right eye, diagnosis in the left eye, and percentage of disability were entered in an Excel spreadsheet and analyzed by SPSS software (version 20.0). Results: Data of 545 persons were analyzed. The mean age ± SD was 36.21 ± 17.70 years. Most of the study population were males (n = 348, 63.85%). The most frequent etiological factors noted are congenital malformations of the eye (20.18%), high myopia (14.13%), corneal blindness (13.58%), trauma (11.56%), optic atrophy (10.46%), retinitis pigmentosa (7.34%), and advanced diabetic eye disease (3.85%). 50% of factors were preventable and nearly 50% were causing progressive worsening of disability. Conclusion: There is a slowly increasing proportion of congenital malformations, congenital cataracts, and glaucoma. Corneal blindness showed a decreasing trend.
Keywords: Certification, preventable blindness, visual disability India
|How to cite this article:|
Sukumaran S, Varma N, Sujatha N, Krishna T D. Etiology of permanent visual impairment among persons attending a disability board in Central Kerala. Kerala J Ophthalmol 2022;34:123-9
|How to cite this URL:|
Sukumaran S, Varma N, Sujatha N, Krishna T D. Etiology of permanent visual impairment among persons attending a disability board in Central Kerala. Kerala J Ophthalmol [serial online] 2022 [cited 2022 Sep 29];34:123-9. Available from: http://www.kjophthal.com/text.asp?2022/34/2/123/355046
| Introduction|| |
Permanent visual handicap is one of the most troublesome disabilities to affect an individual, a family, and a society. As per Census 2011, in India, out of the 121 crore population, about 2.68 crore persons (2.21%) are “disabled.” Approximately 19% of the 2.68 crore persons with disability have a visual disability. Approximately 30% of children with disability have a visual handicap. Visual impairment (VI) includes both low vision and blindness. Some causes of VI are amenable to prevention and treatment.
Visual rehabilitation is the only solution for persons suffering from non-preventable causes of VI or having permanent blindness. The Government of India (GOI) offers many benefits such as jobs, travel concession, income tax benefits, etc., based on the severity of the disability. World Health Organization (WHO) has given certain standards for classifying the severity of the visual disability for each person in the International Classification of Diseases-10. The definition of blindness under the National Program for Control of Blindness (NPCB), GOI differs from the definition adopted by the WHO., Rights of Persons with Disabilities Act, 2016 have further modified these criteria to match that of WHO.
Kerala is the most literate state in India with an excellent three-tier system of healthcare facilities available to all sections of society., There is a well-planned, smoothly functioning, and regular system of the medical board from the secondary care level onwards to provide certificates for persons with disability. Disability board registers are important data sources for research to detect the magnitude of the problem in society. Data are needed on service provision, service outcomes, and the economic benefits of rehabilitation. Evidence for the effectiveness of interventions and programs is extremely beneficial to guide policymakers in developing appropriate services, to allow rehabilitation workers to employ appropriate interventions, and also to support people with disabilities in decision-making. Identifying the major causes of disability is very important for preventive measures. We designed a study of the medical records of one of the disability boards functioning in a district of central Kerala, to determine the etiology, possible preventable causes, and trends of etiological factors for permanent visual disability with an aim to streamline possible preventive and curative services.
| Materials and Methods|| |
This was a retrospective observational study of the data of the medical board of a government medical college hospital in central Kerala from 2017 to 2020 after getting permission from the relevant authority and institutional ethical committee in accordance with the Declaration of Helsinki. The visual disability was certified by a medical board comprising of one ophthalmologist and three other specialists. A thorough examination of visual acuity, anterior segment, and posterior segment of eyes along with required investigations like tonometry, perimetry, gonioscopy, optical coherence tomogram (OCT) are done routinely before certification for all the persons attending the medical board. The medical board follows the guidelines included under the Rights of Persons with Disabilities Act, 2016 (49 of 2016) given in the Gazette of India: Extraordinary [part ii—sec. 3(ii)]for assessing the extent of specified disability in a person. According to this act, in India,
- “Blindness” means a condition where a person has any of the following conditions, after best correction—(i) total absence of sight; or (ii) visual acuity less than 3/60 or less than 10/200 (Snellen) in the better eye with best possible correction; or (iii) limitation of the field of vision subtending an angle of less than 10°.
- “Low-vision” means a condition where a person has any of the following conditions, namely—(i) visual acuity not exceeding 6/18 or less than 20/60 up to 3/60 or up to 10/200 (Snellen) in the better eye with best possible corrections; or (ii) limitation of the field of vision subtending an angle of less than 40° up to 10°. VI certification criteria and gradation vision assessment were done after best possible correction (medical, surgical, or usual/conventional spectacles).
The percentage of VI was calculated according to guidelines issued by the Ministry of Social Justice and Empowerment, GOI [Table 1]. The certificate of disability must be countersigned by the medical superintendent or chief medical officer or civil surgeon or any other equivalent authority as notified by the state. The medical board keeps a well-maintained register regarding the number of patients attending each week with their address, type and percentage of disability, etiological diagnosis, and details of the condition causing disability.
We retrieved the data of all individuals with permanent VI of categories 1 to 4 from the records. Temporary VI and category 0 of permanent disability (less than 20% disability) were excluded. The age, gender, place, diagnosis in the right eye, diagnosis in the left eye, and percentage of permanent visual disability were collected and entered in an Excel spreadsheet and analyzed by SPSS software (version 20.0) manufactured by IBM Corporation, United States of America.
The etiological factors given in the diagnosis were further analyzed and categorized as preventable or non-preventable and progressive, stationary, or regressive. Preventable causes of visual disability were defined as conditions, which can be prevented or treated effectively to prevent permanent visual disability. Non-preventable causes were those conditions leading to permanent disability, which cannot be prevented or treated effectively even with early diagnosis and advanced facilities available now.
Some pathologies are progressive, some static, and some regressive in behavior. Progressive causes are conditions that worsen over time even with treatment. Stationary causes do not change in severity once occurred and regressive causes are those conditions, which improve over time with or without treatment. Statistical analysis was done by SPSS software (version 20.0).
| Results|| |
We analyzed data of 545 persons who attended medical board from January 1, 2017 to January 1, 2021. There were 169 entries in 2017, 193 in 2018, and 156 in 2019; however, only 27 persons attended the medical board in 2020 due to the COVID-19 pandemic effect and lockdown. The mean age ± SD of the study population was 36.21 ± 17.70 years (range 1 to 76 years, interquartile range 21 to 50 years). The mean age of people with permanent visual disability coming for certification to the study center showed a significant (one-way analysis of variance (ANOVA) test P = 0.04) decline with each year. The mean age was 39.12 ± 18.27 years in 2017, 35.80 ± 17.27 years in 2018, 34.42 ± 17.44 years in 2019, and 31.22 ± 16.77 years in 2020. [Table 2] presents the mean age by different categories of visual disability in the study population.
Overall, the study population was predominantly male (n = 348, 63.85%) and did not show a statistically significant gender difference by year (X2 test P = 0.67).
Diagnosis (that lead to the disability) of the right eye and left eye were given in the medical records with the best-corrected visual acuity in each eye. The year-wise distribution and frequency of uniocular diagnosis are shown in [Table 3].
|Table 3: Diagnosis in each eye and the year-wise frequency distribution*|
Click here to view
The most frequent factors noted are congenital malformations of the eyeball or visual pathway, uncorrected refractive errors mainly high myopia leading to amblyopia or other complications, corneal blindness, trauma, optic atrophy, retinitis pigmentosa, and advanced diabetic eye disease. The diagnosis mainly attributed to the categorization of disability is shown in [Table 4]. One hundred and fifty-eight cases (28.99%, 95% CI: 25.34, 32.94) were categorized as one-eyed (category 2).
The trend analysis showed a slowly increasing frequency of congenital malformations, congenital cataracts, and glaucoma over the years from 2017 to 2019. Corneal blindness showed a decreasing trend [Table 4].
We also analyzed whether the causative factors were preventable or non-preventable and found that half of the pathologies were either preventable or effectively treatable. Regarding the natural course of diseases, about half the causative diseases were progressive in nature. See [Table 5].
|Table 5: Frequency distribution of categories of permanent visual disability, preventable/non-preventable causes of blindness, and progressive/static/regressive blindness detected by this study|
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| Discussion|| |
As per the “Survey of Persons with Disabilities in India” conducted during the National Sample Survey Organization (NSSO) 76th round (July–December 2018), the prevalence of disability is 2.2 percent in India, and 0.3% of the rural population and 0.2% of the urban population suffer from a visual disability.
The NSSO-2002 reported that VI is a problem of old age in India. About 68 to 72% acquired VI at the age of 60 years and above and the causes were shown as “old age” and cataract. The Aravind comprehensive eye survey of blindness and vision impairment in a rural south Indian population, done in the same period also showed age-related cataract was the most common potentially reversible blinding disorder (72.0%) among eyes presenting with blindness. However, better facilities and access to eye care are leading to a shift in this paradigm. Better survival of preterm infants and children with congenital anomalies has increased the proportion of younger age groups with visual disabilities. We found a greater number of younger aged people attending the study center for certification with each year [Table 2]. It is also possible that the increasing proportion of younger aged people coming for certification is related to the various benefits and job opportunities given to disabled persons. This may provide an incentive to the young to get the certificate if they have any disability. Several recent studies have shown that most of the applicants belong to the age group of 16 years to 45 years.,,,
We found a higher proportion of males with disability in the study population although the difference was not statistically significant [Graph 1]. The higher proportion of males with a disability is comparable to other studies from India.,,,, The lack of significance possibly indicates that more females are coming forward to receive certification for various benefits.
Category C (40–80%) disability was more common in this series [Table 2] similar to other South Indian studies,, but different from the studies by Khan et al. and Ghosh et al. They found that a maximum number of applicants belonged to the blindness (100%) category. This may be because of the difference in population included in the study or maybe related to the awareness of possible benefits from certification among those with visual disabilities. In our population, only 89 cases (16.33%) had category 4 (90–100%) disability [Table 2] suggesting that more people with lesser grades of visual disability were willing to obtain certificates.
Many of the patients [158 cases (29%)] who appeared before the medical board were category 2 (one-eyed) patients with 30% visual disability [Table 4] and [Table 5]. This observation is consistent with that of Khan et al.
Congenital malformations of the eye, high myopia, corneal causes, trauma, optic atrophy, retinitis pigmentosa, diabetic eye disease, retinal detachment, and glaucoma were the main causes of permanent visual disability in our series [Table 4]. This result is similar to that of other South Indian studies by Khan et al. and Dadapeer Kareemsab et al. but Ambastha A, et al. found that the most common cause of visual handicap (40–100% impairment) and blindness (75–100% impairment) was macular pathology (p <.05), while the most common cause of overall VI (20–100% impairment) was amblyopia. Congenital abnormalities were fourth in their frequency order [Table 4]. The difference may be because of the different populations involved in the studies.
The most frequent etiological factor in our study was congenital malformations of the eyeball and visual pathway including microphthalmos, microcornea, coloboma, anterior segment dysgenesis syndromes, and congenital nystagmus [Table 4]. There were two cases of anophthalmia also. These are non-preventable in the present scenario. The possibility of prevention lies at the level of genetic counseling, prevention of consanguineous marriage (which is still a common practice in South India), and effective prenatal diagnosis of congenital abnormalities. Another important perinatal cause was congenital cataract [Table 4] and all these cases had received cataract surgery. But none of them had perfect vision, may be because of delayed surgery or inadequate post-operative follow-up and improper management of amblyopia. Another aspect noted was only one-third of cases were pseudophakic. Strengthening the pediatric ophthalmology subspecialty for early surgery, efficient post-operative follow-up, secondary intraocular lens (IOL) implantation in time, and prevention of amblyopia are very essential and may help to reduce the magnitude of permanent visual disability due to congenital cataracts. Congenital cataracts, strabismus, and amblyopia are preventable/treatable causes of disability if there are facilities.
The second commonest etiological factor in this series was uncorrected refractive errors with most having high myopia [Table 4]. Amblyopia and the complications of pathological myopia equally contributed to the development of disability. Though we cannot prevent the occurrence of all refractive errors, early detection, correction, and treatment of complications with proper follow-up can lead to a tremendous reduction of visual disability. Government and the public health system can implement regular school health programs with ophthalmological examination from kindergarten level onwards for the same.
Corneal blindness had the highest frequency in 2017 and was reduced to the third common etiology in the study population [Table 4]. Corneal opacity, dystrophy, failed graft, chemical burns, Steven–Johnson syndrome, and phthisis due to perforation of corneal ulcer were included in this group. This is also a preventable/treatable factor. Many cases were failed grafts exposing the need for better facility and surgical training in the field of keratoplasty. The decreasing trend of this causative factor over the years is significant and encouraging. We did not have trachoma or vitamin A deficiency as causative factors.
We found trauma as another important etiological factor causing disability for the productive age group [Table 4]. There was an increase in the number of cases in recent years, similar to the findings of other studies., This may be due to the fact that the ocular injuries in road traffic accidents and injuries in factory workers are increasing. Two-thirds of our cases were open globe injuries and the remaining traumatic optic neuropathy. Most of them resulted in uniocular total loss of vision contributing to category 2 (30%) disability. We included this in the non-preventable group as most of them reach the specialist after the golden hours of treatment and most are irreversible once it has occurred. The plight of one-eyed persons needs attention. They face all the challenges and disadvantages of uniocularity like driving difficulties, decreased field of vision, loss of job, mental agony, and inferiority complex of being one-eyed. At the same time, they do not have access to benefits as a disabled person. According to the guidelines for disability by the Ministry of Social Justice and Empowerment of the GOI, the minimum degree of disability should be 40% for an individual to be eligible for any concessions or benefits. Enforcement of traffic rules, applying strict safety precautions in the worksite, appropriate timely treatment, etc., can decrease the incidence of this mishap.
Advanced diabetic eye disease is another emerging major risk factor for progressive visual disability in our population [Table 4]. Kerala is the diabetic capital of India and has double the national average of 8%., Serious effort must be taken from the grass root level for controlling this lifestyle disease and its complications. Timely screening of all diabetic patients for retinopathy must be instituted. Public awareness regarding diabetic retinopathy also can play a big role in early detection and management. We had a significant number of retinal detachments in the diagnosis similar to other Indian studies., The increase in retinal detachment may be secondary to pathological myopia, post-cataract surgery, and diabetic retinopathy. So, strengthening the vitreoretinal subspecialty at all levels of healthcare is the need of the hour.
The number of glaucoma cases in our study was less (2.93%) compared to other studies., The public awareness, regular glaucoma screening camps, and clinics may be the reason for the reduction of glaucoma as a causative factor for permanent visual disability. Another possibility is patients may not be aware of the field defect they are having and the significance of the field of vision in the calculation of the percentage of disability. The increasing trend observed over the years supports this explanation.
The strength of this study is the recognition of the basic pathology of each causative factor. For example, phthisis is a very commonly written diagnosis in disability certificates. We analyzed its causation - whether it occurred following a traumatic rupture globe or endophthalmitis or a perforated/eviscerated corneal ulcer. Vitreous hemorrhage, retinal detachment, and neovascular glaucoma following diabetic retinopathy were classified under advanced diabetic eye disease. This enabled us to identify the underlying disease, whether it could be preventable or treatable at any point of time. Depending on the natural course of diseases, we classified them as progressive, regressive, or static. Overall we found that around 50% of etiological factors were preventable. Nearly 50% of diseases were causing progressive worsening of disability [Table 5]. As the condition changes, the type of support including health benefits, special equipment for support, work accommodation, etc., also needs to change. The trend analysis [Table 4] showed a slowly increasing proportion of congenital malformations, congenital cataracts, and glaucoma suggesting the need for special attention to tackle these in the coming years. Corneal blindness showed a decreasing tendency over the years suggesting the success of already implemented measures and encouraging further progress in the same direction. The etiological distribution highlights the need to strengthen ophthalmology training in subspecialties and to introduce more programs with a subspecialty focus.
Limitation of the study
We studied the data of only one medical board of the district and the data may not be representative of the entire district. A larger study of all the boards of the district, state, and country is possible at a low cost and will give a clearer picture.
| Conclusion|| |
Congenital malformations of the eyeball, high myopia, corneal causes, trauma, optic atrophy, retinitis pigmentosa, diabetic eye disease, and retinal detachments are the main causes of permanent visual disability in our series of permanent visual disabilities and 50% of them are preventable. The trend analysis showed a slowly increasing frequency of congenital malformations, congenital cataracts, and glaucoma. The etiological distribution highlights the need to strengthen ophthalmology training in subspecialties and to introduce more programs with a subspecialty focus.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]