Are current guidelines for categorization of visual impairment in India appropriate?

Context: Visual disability in India is categorized based on severity. Sometimes the disabled person does not fit unambiguously into any of the categories. Aims: To identify and quantify disability that does not fit in the current classification, and propose a new classification that includes all levels of vision. Settings and Design: Retrospective chart review of visual disability awarded in a teaching hospital. Materials and Methods: The last hundred records of patients who had been classified as visually disabled were screened for vision in both eyes and percentage disability awarded. Data were handled in accordance with the Helsinki Declaration. Results: Twenty-one patients had been classified as having 30% disability, seven each had 40% and 75%, and 65 had 100% disability. Eleven of them did not fall into any of the current categories, forcing the disability board to use its own judgment. There was a tendency to over-grade the disability (seven of 11; 63.6%). The classification proposed by us is based on the national program for control of blindness' definition of normal vision (20/20 to 20/60), low vision (<20/60 to 20/200), economic blindness (<20/200 to 20/400) and social blindness (<20/400). It ranges from the mildest disability (normal vision in one eye, low vision in the other) up to the most severe grade (social blindness in both eyes). Conclusions: The current classification of visual disabilities does not include all combinations of vision; some disabled patients cannot be categorized. The classification proposed by us is comprehensive, progresses logically, and follows the definitions of the national program.

Visual impairment disability in India is categorized based on its severity.Percentages are accorded as proposed by a subcommitt ee constituted by the Ministry of Social Justice and Empowerment in 1999.The categories of visual disability are notifi ed in the Gazett e of India, extraordinary, 2001 and are followed all over the country. [1]On using the classifi cation over the years, we have come across instances of visual disability that do not fi t into any of the categories.Thus, disability certifi cation board members have to rely upon their own discretion in categorizing some cases.This study was aimed to identify and quantify those cases and propose a new classifi cation that includes all levels of visual acuity.

Materials and Methods
The current classifi cation of visual disability was critically examined to determine which combinations of vision did not find a place in the classification.In addition, the last hundred records of patients who had been classified as visually disabled in this hospital were screened.Data relating to vision in both eyes and the disability percentage accorded by the disability board was retrieved and entered into an MS Excel worksheet.To protect anonymity, the names of patients were not noted; we identifi ed them by serial numbers.Data were handled in accordance with the ethical standards of the Helsinki Declaration of 1975, as revised in 2000.The disability percentage recorded by the board was compared with the current classifi cation, in order to determine the extent and type of disparity, if any.Finally, a classifi cation was created using the national program for control of blindness (NPCB) defi nitions of normal vision, low vision, and blindness, and including every possible combination of vision in the two eyes of a visually disabled patient.

Results
Table 1 shows the categories of visual disability that are currently in use all over India. [1]Of the 100 visual handicap records that were screened for this study, 21 persons had been classifi ed as having 30% disability, seven each had 40% and 75%, and 65 had 100% visual disability.Eleven of these persons did not fall into any of the current categories of visual disability [Table 2]; nevertheless, the institutional visual disability board had used its own judgment.The percentage of disability awarded to these 11 persons is detailed in Table 2.The tendency was to over-grade the disability (seven of 11 disabilities; 64%), giving the applicant the benefi t of this loophole in the classifi cation system.

Discussion
Most persons seeking visual disability certifi cation in this institution do so for severe disability (75-100% category).However, even one-eyed persons (30% disability) request certifi cation.This occurs in spite of the Ministry of Health's notifi cation that a person with <40% disability will not be eligible for benefi ts/concessions. [1]They contend that clubbing one-eyed persons with other visual handicap categories will dilute the benefi t to the latt er.In this respect, certifi cation of oneeyed persons might be considered a wasteful exercise, causing unnecessary expenditure of resources in the certification process.On the other hand, in multiple disabilities, even a relatively small visual disability could make a diff erence in the fi nal certifi cation.There is a provision to combine the eff ects of multiple disabilities, particularly those involving neurological and musculoskeletal systems. [1]The disability with the lower score (b) is added to the highest score (a) and fi nal disability is calculated using the formula: This means that a person with 25% neurological and 20% visual disability would have a combined disability of 40%, thus entitling him to benefi ts and concessions.3] includes all combinations of vision in the two eyes.There are nine possible grades of disability based on the NPCB classifi cation of normal vision (20/20 to 20/60), low vision (<20/60 to 20/200), economic blindness (<20/200 to 20/400) and social blindness (<20/400). [2]owever, while the NPCB defi nitions use presenting vision, we recommend best-corrected visual acuity (BCVA).Assessing presenting vision is practicable in fi eld situations, but when a person presents for disability certifi cation, every att empt should be made to improve vision before certifying.The current classifi cation of disability too uses BCVA. [1]e proposed classification is comparable with the classifi cation of visual impairment recommended by the World Health Organization (WHO) [Table 4]. [3]Persons with low vision in both eyes, in the proposed classifi cation, correspond to category I of the WHO classifi cation, persons with bilateral economic blindness correspond to category II, and persons with bilateral social blindness correspond to categories III, IV and V.As in the WHO classification, persons with no perception of light have been given a separate identity.These  The proposed classifi cation is comparable with the one currently in use in that vision reduction upto and including 20/60, in both eyes, is considered normal.The current classifi cation awards 20, 30 or 40% disability to persons with normal vision in one eye but fails to categorize many visual combinations [Table 2].Forty percent disability will enable one-eyed persons to compete for benefi ts and concessions with the severely visually disabled, to the disadvantage of the latt er.The proposed classifi cation has also created three classes for one-eyed persons, but does not go higher than 30% disability.

The new classifi cation suggested by us [Table
Most combinations for persons with bilateral low vision are missing from the current classification.The rest are awarded 40% disability.The proposed classifi cation misses none, awarding 40% disability to all.Persons with low vision in the bett er eye and economic blindness in the worse eye are awarded 40% disability in the current classifi cation; some visual combinations are missing.The proposed classifi cation misses none, and awards them 50% disability.The diff erence of 10% in disability status should not make much diff erence since both will be eligible for concessions or benefi ts.b: These categories are intended to correspond with the fourth digit of the numbering system used in the International Classifi cation Diseases.In this system, the digit 9 customarily signifi es "unspecifi ed".
For persons with low vision in the bett er eye and social blindness in the worse eye, the current classifi cation awards 40% or 75% disability.In our opinion, 40% disability is unfair since these persons are defi nitely more disadvantaged than those described in the preceding paragraph (low vision in one eye and economic blindness in the other).On the other hand, 75% disability may be too generous; they are in a bett er position than persons with economic blindness in both eyes.Thus, the proposed classifi cation awards them 60% disability.
Persons with economic blindness in both eyes are awarded 75% disability using the current, and 70% using the proposed classifi cation.Many visual combinations are missing in the current classifi cation but not in the proposed one.The current classifi cation awards 75 or 100% disability to persons with economic blindness in the bett er eye and social blindness in the worse eye, but misses some visual combinations.The proposed classifi cation misses none and awards 80% disability to them.
The current classifi cation awards 100% disability to persons who have social blindness in both eyes, but misses many visual combinations.We suggest such persons be awarded 90% disability except when they have no perception of light in both eyes (suggesting an incurable condition), when they can be awarded 100% disability.
It was considered during formulation of this classifi cation, that visual disability of <40% could be abolished altogether since no benefi ts or concessions accrue to them.However, if multiple disabilities are present, even 20% visual disability may allow the person to get benefi t from educational and job schemes.Thus, lower degrees of visual disability must continue to have a place in the disability classifi cation.In the proposed classifi cation, the diff erence between grades is 10%.The spectrum varies from the mildest disability (normal BCVA in one eye but low vision in the other) up to the most severe grade (social blindness in both eyes).
The proposed classification has several strengths to recommend it.It follows the NPCB defi nitions of low vision and blindness, thus being in uniformity with the national program.It is in tandem with the WHO classifi cation of visual disability, thus giving it international comparability.It is more or less comparable with the current classifi cation in India; the fi eld defects commensurate with low vision and blindness are also the same; BCVA is the criterion in both classifi cations.It includes every possible combination of vision in the two eyes.In addition, it provides a wider range of disability.This may be of use to a person having multiple disabilities.The proposed categories follow a natural progression making them logical and easy to remember.

Table 1 : Categories of visual disability (classifi cation currently in use) 1
*with correcting lenses

Table 2 : Vision grades that do not fi t into the current visual disability classifi cation No place in the current Number of patients Disability awarded Interpretation of disability classifi cation in our series (n=100) by Board members (%) disability awarded*
PL-perception of light, *based on the existing classifi cation of visual disability 1 , † close to appropriate persons are likely to have incurable ocular conditions and be in need of long-term support and concessions.The proposed classifi cation is in agreement with the WHO classifi cation for fi elds of ten degrees or less, and closely comparable with the NPCB classifi cation for fi elds greater than ten degrees and up to 20 degrees.

Table 3 : Proposed new visual disability classification based on the NPCB defi nitions of normal vision, low vision, economic blindness and social blindness BCVA in the better eye BCVA in the Percentage of worse eye disability
BCVA-best-corrected visual acuity, *or fi eld of vision greater than 10 but no more than 20 degrees, † or fi eld of vision ≤10 degrees

Table 4 : Classification of severity of visual impairment recommended by WHO 3 Category of Visual acuity with both eyes using visual best possible correction* impairment
If the extent of the visual fi eld is to be considered also, patients with a fi eld of less than 10 but more than 5 degrees around central fi xation should be placed in category 3 and patients with a fi eld less than 5 degrees around central fi xation should be placed in category 4, even if the central acuity is not impaired. a: