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ORIGINAL ARTICLE
Year : 2014  |  Volume : 2  |  Issue : 2  |  Page : 99-101

Improving functional vision in school for the blind students with low vision aids in Pune, India


1 Bharti Vidyapeeth Medical College, School of Optometry, Pune, India
2 Community Eye Care Foundation, Dr. Gogate's Eye Clinic, Pune, India
3 Department of Ophthalmology, Bharti Vidyapeeth Medical College, Pune, India

Date of Submission24-Jun-2013
Date of Acceptance19-Feb-2014
Date of Web Publication11-Apr-2014

Correspondence Address:
Parikshit M Gogate
Community Eye Care Foundation, Dr. Gogate's Eye Clinic, K-102, Kumar Garima, Tadiwala Road, Pune - 411 001
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2320-3897.130539

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  Abstract 

Context: Many students admitted in schools for blind have some vision. Aim: To study cause of blindness (<6/60) and functional vision improvement in visually impaired students by providing optical low vision aids (LVAs). Setting and design: Prospective series among schools for blind students. Materials and Methods: Ocular evaluation of students enrolled in special schools in Pune district was done using World Health Organization's eye examination protocol. Medical records of the students were examined and ocular examination done by using torchlight, slit lamp examination, ophthalmoscopy and retinoscopy and visual acuity estimation with low vision assessment. The logMAR chart at a distance of 4 m and reduced Snellen's acuity charts and LVAs were used. Results: Four hundred and sixty students were examined; their mean age was 12.6 years (std dev 3.3 years, range 5-20 years) and 246 (53.5%) were males. Four hundred and fifteen (90%) were blind since birth. The students were blind due to microphthalmos and anophthalmos 142 (30.9%), cornea 60 (13%), lens 78 (16.9%), uvea 5%, retina 43 (9.3%) including retinopathy of prematurity (ROP) and optic nerve lesions 6%. LVA for distance was prescribed to 59 students (12.8%) who improved >1 line and for near was prescribed to 72 students (15.7%) of whom 68 attained N6-N12 acuity. Seventy-seven (16.7%) of the total students were benefited with LVA. Conclusion: LVA prescription improved visual acuity of 'blind' students and allowed them to learn and read print. ROP was a new addition in past decade as the cause of blindness.

Keywords: Causes of blindness, functional vision, low vision, schools for blind, severe visual impairment


How to cite this article:
Israfil AT, Gogate PM, Kulkarni V, Shinde A. Improving functional vision in school for the blind students with low vision aids in Pune, India. J Clin Ophthalmol Res 2014;2:99-101

How to cite this URL:
Israfil AT, Gogate PM, Kulkarni V, Shinde A. Improving functional vision in school for the blind students with low vision aids in Pune, India. J Clin Ophthalmol Res [serial online] 2014 [cited 2022 Jun 28];2:99-101. Available from: https://www.jcor.in/text.asp?2014/2/2/99/130539

Students whose severe visual impairment and blindness cannot be treated medically or surgically are enrolled in special school for the blind where most instructions are in Braille. Numerous studies from India have shown that students in schools for the blind have some functional vision which can be put to good use. [1],[2],[3],[4],[5] These students could be taught to read print in addition to Braille, as this would enormously improve their career options and economic prospects. Such students could also attend integrated schools which would help not just their academic but also social and emotional development. [2],[6] The aim of this study was to find the causes of blindness in special education school's students in Pune district, compare it with causes in the same schools documented 8 years earlier and to gauge how many students improved by use of low vision aids (LVDs). [1]


  Materials and Methods Top


This was a prospective study conducted in schools for blind in Xxx district. The study was approved by the institute's ethics committee. The students were examined and findings were recorded as per 'WHO/PBL Eye Examination Record For Children With Blindness And Low Vision'. [7] These schools had earlier been examined in 2002-03. [1]

The examination was done within the leisure of each standard. History of patients was obtained from the records available in the school. Each student's name, home town or village, age, gender, ethnic group and age of onset were recorded.

Students were examined if they were with or without spectacles or any LVDs (LVA). Vision for distance was estimated using the logMAR chart keeping the distance of 4 m from the patient. Reduced Snellen's chart was used to assess near vision. Functional vision was determined by the four grades as made in the WHO protocol - ability to walk around independently, ability to recognize faces, ability to see prints (2 lines of N10 letter size) and the students who could use the residual vision. [7]

Slit lamp examination and fundoscopy was conducted and along with this refractive error, amblyopia and/or idiopathic nystagmus were noted. The major site of abnormality leading to visual loss for the child was also recorded.

Objective refraction was done using the Heine Beta 200 R Retinoscope. Subjective retinoscopy was done using the logMAR chart under sufficient light and with the help of trial frame and set. Proper illumination of the examination room and the chart in all the schools were strictly maintained during the LVA assessment.

The following steps were maintained in prescribing LVA for distance:

  1. Localization
  2. Focusing
  3. Spotting
  4. Tracing
  5. Tracking
  6. Scanning


Prescribing low magnification LVAs also provided the user to acquire comparatively larger field of view and easy in tracing and tracking techniques.

Assessment of LVAs for a distance was done by the following formula:

Magnification Required = Required visual acuity/Present visual acuity

An approximate requirement of LVA for near could be estimated whose unaided distance or near visual acuity was measured.

Assessment of LVA for near was done by the following formula:

Magnification Required = Present visual acuity/Required visual acuity

For the evaluation of near vision reduced Snellen's charts were used, under adequate room illumination. Illuminated stand magnifier of 5x and 7.5x, non-illuminated stand magnifier of 2.5x and 7.5x, bar magnifier, fresnel prism, hand held magnifier of 20 diopter (D), 30D and 35D and spot magnifiers of 24D, 32D, and 40x were used for trial. For the students who failed to read at least N26 with the required or best benefited LVA, an additional luminance of 50 lumens was provided. This procedure was not done in exceptional cases like albinism.

The trial for LVA was done in right and left eye separately. And use of LVA was noted for the eye which showed to attain the maximum visual acuity in the particular candidate. Accordingly, a copy of medical record of students was given to respective schools, so that the authority can take necessary steps to provide LVAs. The teachers of the school were also asked whether the student should continue in the present school, or should be shifted to integrated educational centers. All the data recorded were analyzed statistically using Microsoft Excel and SPSS software.


  Results Top


A total of 460 students were examined; their mean age was 12.6 years with a standard deviation of 3.3 years, range 5-20 years; of them 246 (53.5%) were males. Four hundred and fifteen (90%) were blind since birth.

The presenting visual acuity (VA) of both eyes was noted. One hundred and sixty four students were revealed to be perception of light (PL) negative, whereas 99 students were PL positive. One student attaining highest VA was log 0.6 and another attained log 0.3. The first one was diagnosed as albinism, whereas the later one had refractive error.

Functional vision was recorded by assessing the day-to-day life activities. Of the students examined, 192 (41.7%) could see enough to walk around independently, 116 (25.2%) could recognize faces and 82 (17.8%) were able to see print.

The major causes of blindness and severe visual impairment (SVI) are depicted in. The students were blind due to microphthalmos and anophthalmos 142 (30.9%), cornea 60 (13%), lens 78 (16.9%), uveitis 5%, retina 43 (9.3%) including retinopathy of prematurity (ROP) and optic nerve lesions 6%. The corneal causes were phthisis 16 (3.5%), anterior staphyloma 48 (10.4%), corneal opacity in 23 (5%), corneal dystrophy 17 (3.7%), keratoconus 7 (1.5%), scarring 6 (1.3%) and microcornea 3 (0.7%). Buphthalmos was observed in 3 (0.7%) students while 2 students had their eyes removed. Retinal dystrophies were found in 17 (3.7%), albinism in 10 (2.2%), retinitis pigmentosa in 7 (1.5%), retinopathy of prematurity in 6 (1.3%) and central retinal vein obstruction in 3 (0.7%) students. All children with lens opacities were referred to a comprehensive eye care center.

As all the students were the first time user of LVAs, 2.25x and 3.5x telescopes proved to be a good option. LVA for a distance was prescribed for 59 (12.8%) students; out of whom 48 were prescribed for 2.25x magnification and 11 were for 3.5x.

LVA for near was prescribed to 72 (15.7%) students. The 5x illuminated stand magnifier proved to be user friendly to students. Shows the various devices prescribed for near vision. With the LVA most of the students acquired near vision N10-N12, 5 out of 460 students were able to see N6 letter size. Demonstrates the final near vision acuity acquired after LVAs.

The mean visual acuity of the 460 students in the right eye was finger counting at 2 m (logMAR value1.47) which improved to 6/60 (logMAR value of 1.0). And similarly in the left eye the unaided visual acuity which was finger counting a 2 m which had improved to a logMAR value of 0.9. In all, 77/460 (16.7%) students were prescribed LVA and their vision improved. Five students were prescribed LVAs only for near whereas 72 accepted and improved with LVA for both near and distance.


  Discussion Top


A large number of students in school for blind were congenitally blind due to abnormality of the globe. So, most of the individuals had no perception of light. But SVI students could use their residual vision for functional purposes. Some of the candidates could see to walk around and see faces and prints (minimum N24, maximum N6). The purpose of the prescribing LVAs was to improve their residual vision for functional use.

The causes of blindness and visual impairment were similar to the study done in the same population 10 years ago, microphthalmos and anophthalmos being the leading cause, except for retinopathy of prematurity which was not seen a decade ago. [1] Corneal causes had further declined as a cause of blindness while lenticular causes (cataract, aphakia) had become relatively more common. The retinal dystrophies were much less than the series from Karnataka. [4]

All the students (except PL negative) were given a trial of LVAs. In this 77 (16.7%) had improved at least one step of VA assessment as per the WHO protocol. SVI individual preferred self-illuminated stand magnifiers rather than non-illumination pattern of the same magnification. And in distance, LVA 2.25x was preferred over a 3.5x magnification telescope.

In similar studies from London, UK, 35.7% students improved with LVA. [8] In another study it was found the child's need for near LVAs could be predicted from their age, unmagnified reading performance, and visual field characteristics. [9],[10]

In a cross-sectional study done in 13 special education schools in Delhi, high additional plus lenses were used as spectacle magnifiers for near and resulted in 20.3% children improving by at least one WHO category of blindness. [2] The children who benefitted most by LVA were those with aphakia (17), followed by coloboma (5), refractive error (5) and microphthalmos (4). The authors concluded that visually impaired children with aphakia and ocular congenital anomalies benefit from refraction and low vision services. [2]

A comparative study done by Silver J and Gould E between 60 students of integrated school and 34 children attending partially sighted school stated that the integrated children tended to be more intelligent. [10] More students could avoid special schools if given appropriate services at an early age and assessment by examiners and team.

In a study done on 345 students of 12 Schools for blind in Nepal it was found 64.2% had avoidable blindness. Fifty-seven (28.2%) students could read smaller than 2 M print size after low vision assessment for near and 33 (15.8%) students benefited with telescopic trial for distance low vision, similar to results of this study. [11]

A study conducted by Cardiff University on 168 people revealed that after a low vision assessment and provision of a suitable LVD 88% of patients were able to read N8 or smaller text. [12]

The study was limited by the fact that telescopes of only two options (2.25x and 3.5x) were available for the distance LVA assessment. All the students in the schools for blind were taught Braile instead of English or Marathi (the regional language), particularly in the lower standards. Students learnt English after they were promoted to fifth grade. The logMAR chart used in the study had English letter optotype. So, some of the patients who could probably see (suppose a letter size of log 1.0) could not identify the letters. So these letters were first explained and then VA estimation was done. Only two kinds of near aids were available. We do not have a long-term follow-up of these students.

Proper evaluation of students admitted in the blind school should be performed at least once in a year to tackle treatable and avoidable blindness. A joint effort on part of optometrist and ophthalmologist and schools for blind could reduce the number of students in these schools. Regular low vision assessment could result in many students being enabled to read and learn print and getting into integrated education and having more choices of vocation and recreation in the future and develop their potential to its truest extent.


  Acknowledgement Top


We are thankful to the Principals and students of the following schools for the blind.

 
  References Top

1.Gogate P, Deshpande M, Sudrik S, Taras S, Kishore H, Gilbert C. Changing pattern of childhood blindness in Maharashtra, India. Br J Ophthalmol 2007;91:8-12.  Back to cited text no. 1
    
2.Pal N, Titiyal JS, Tandon R, Vajpayee RB, Gupta S, Murthy GV. Need for optical and low vision services for children in schools for the blind in North India. Indian J Ophthalmol 2006;54:189-93.  Back to cited text no. 2
[PUBMED]  Medknow Journal  
3.Bhattacharjee H, Das K, Borah RR, Guha K, Gogate P, Purukayastha S, et al. Causes of childhood blindness in the northeastern states of India. Indian J Ophthalmol 2008;56:495-9.  Back to cited text no. 3
[PUBMED]  Medknow Journal  
4.Gogate P, Kishore H, Dole K, Shetty J, Glibert C, Ranade S, et al. The pattern of childhood blindness in Karnataka, South India. Ophthalmic Epidemiol 2009;16:212-7.  Back to cited text no. 4
    
5.Titiyal JS, Pal N, Murthy GV, Gupta SK, Tandon R, Vajpayee RB, et al. Causes and temporal trends of blindness and severe visual impairment in children in schools for the blind in North India. Br J Ophthalmol 2003;87:941-5.  Back to cited text no. 5
    
6.Silver J, Gilbert CE, Spoerer P, Foster A. Low vision in east African blind school students: Need for optical low vision services. Br J Ophthalmol 1995;79:814-20.  Back to cited text no. 6
    
7.Gilbert C, Foster A, Negrel AD, Thylefors B. Childhood Blindness: A new form of recording causes of vision loss in children. Bull World Health Org 1993;71:485-9.  Back to cited text no. 7
    
8.Rudduck G, Corcoran H, Davies K. Developing an integrated paediatric low vision service. Ophthalmic Physiol Opt 2004;24:323-6.  Back to cited text no. 8
    
9.Leat SJ, Karadsheh S. Use and non-use of low vision aids by visually impaired children. Ophthalmic Physiol Opt 1991;11:10-5.  Back to cited text no. 9
    
10.Silver J, Gould E. A study of some factors concerned in the schooling of visually handicapped children. Child Care Health Dev 1976;2:145-53.  Back to cited text no. 10
    
11.Kansakar I, Thapa HB, Salma KC, Ganguly S, Kandel RP, Rajasekaran S. Causes of vision impairment and assessment of need for low vision services for students of blind schools in Nepal. Kathmandu Univ Med J 2009;7:44-9.  Back to cited text no. 11
    
12.Margrain TH. Helping blind and partially sighted people to read: The effectiveness of low vision aids. Br J Ophthalmol 2000;84:919-21.  Back to cited text no. 12
    



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