Indian Journal of Otology

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 25  |  Issue : 1  |  Page : 18--21

Visual defects in hearing-challenged schoolchildren from Ludhiana, Punjab


Renu Thakur1, Jaikishan JayaKumar2, Sangeeta Pant3,  
1 Sankara Academy of Vision, Sankara Eye Hospital, Ludhiana, Punjab, India
2 Center for Computational Brain Research Indian Institute of Technology, Chennai, Tamil Nadu, India
3 Chitkara College of Education, Chitkara University, Punjab, Chandigarh, India

Correspondence Address:
Prof. Renu Thakur
Village Bhanohar, Post Dhaka, Ferozepur-Ludhiana Road, Near Wadi Haveli, Ludhiana - 141 101, Punjab
India

Abstract

Purpose: We compared Visual attention of normal hearing students and congenitally deaf students, Deaf students are visually depended; respective study help us to find out visual attention of Deaf as compared with age matched hearing students. Method: Total 118 deaf students aged from 6 to 25 years were screened from School for the Deaf Children, Kitchlu Nagar, Ludhiana Punjab 141001. 30 students were randomly selected from age group 8.5 to 11.11 years. All 30 deaf students where compared with age-matched hearing students from Peace Public School NH 95, Ferozepur - Ludhiana Road, Ludhiana, Punjab 141102. Informed consent was taken from all students pears, all the participants where having best corrected distance visual acuity 6/6 (snellen chart) and near visual acuity N6. Anterior and Posterior eye examination where evaluated in Sankara Eye Hospital Ludhiana, prior to the test; Visual attention was evaluated using two different test type, SDMT Symbol digit Modality test and Attention Blink by Visual attention Brain Baseline App. Result: Symbol Digit Modality Test; didn't show significant difference between. Deaf (N= 30) and Hearing students (N=30), Deaf students (Mean 0.97, S.D 2.57 and SEM 0.47), Hearing students (Mean 0.47, S.D 0.97, SEM 0.18) T-ratio 1 and P-Value 0.32 there was no difference between deaf and hearing impaired group. Visual attention- Brain Baseline App, the attention blink showed significant difference between Deaf and hearing impaired students. Deaf students (Mean 0.09, S.D 0.08 and SEM 0.02), Hearing students (Mean 0.22, S.D 0.18, SEM 0.03) T-ratio 3.41 and P-Value 0.001. Conclusion: Deaf group had made less error, deaf showed better attention as compare with hearing group. This finding indicates that deaf students are having better attention in the central visual attention. It can be one of the factors for peripheral distraction of deaf students.



How to cite this article:
Thakur R, JayaKumar J, Pant S. Visual defects in hearing-challenged schoolchildren from Ludhiana, Punjab.Indian J Otol 2019;25:18-21


How to cite this URL:
Thakur R, JayaKumar J, Pant S. Visual defects in hearing-challenged schoolchildren from Ludhiana, Punjab. Indian J Otol [serial online] 2019 [cited 2019 Jul 20 ];25:18-21
Available from: http://www.indianjotol.org/text.asp?2019/25/1/18/260725


Full Text



 Introduction



Deafness or hearing impairment is a relatively common form of sensory deficit found in children. The number of infants who are born deaf is 1 for every 1000 infants,[1] with more children acquiring various degrees of hearing impairment within the first 2 years of life.[2] These numbers remarkably are similar in most countries.[3] Hearing deficit is a major problem in the society, with almost one-third of prelingual children in Nepal unable to acquire their speech and language.[4] Studies have indicated that the prevalence of ocular abnormalities among the deaf and hearing impaired is higher than that of the general population of comparable age group.[3] Although this association is unclear, one hypothesis suggests that it may be due to the close anatomical relationship of the retina and cochlea which develops from the same embryonic layer.[5] It is also generally claimed that visual input accounts for 75% of all sensory information acquisition, and hearing and vision together account for almost all sensory inputs.[6] The coexistence of hearing and visual impairment in children predisposes them to many challenges including difficulties in communication, learning, and social interaction.[7] It is often proposed that, when one sense is impaired, another sense often compensates for the disability, for example, the hearing impaired may compensate by making greater use of visual-perceptual cues than their normal-hearing peers. However, any visual deficits, for example, refractive error, result in the reduction of the available visual cues, and thus has a significant impact on the lifestyle of the hearing impaired.[8] The prevalence of visual deficits in the schoolgoing hearing-impaired population is remarkably similar in most countries across the world irrespective of their socioeconomic status. The prevalence ranges between 33% and 75% in the United States,[9],[10] 43% in the UK,[11] and among the developed countries to 32%–73% in sub-Saharan Africa.[6],[12] In India, the seminal study by Gogate et al.[13] in a set of hearing-impaired schools in Maharashtra found a prevalence of ocular disorders to be 24% among the hearing-impaired schoolgoing population. Compared with the data from other countries, this was a surprisingly low percentage, and one of our goals was to confirm these findings. In order to achieve our goals in this study, we wanted to determine the prevalence of visual deficits in a population of hearing impaired by screening for visual deficits in a schoolgoing population of deaf children in Ludhiana, Punjab.

 Materials and Methods



All methods used in this study include routine noninvasive clinical techniques, which are routinely used in the detection of visual disorders. The procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional or regional) and with the Helsinki Declaration of 1975, as revised in 2000. Prior permissions and approval were sought and obtained from the head principal of the hearing-impaired school. In addition, the teachers of the school were given information briefing the methods used in the study. This was done to help in communication (sign language) with the students. The researchers were also well versed with the sign language used in the school.

The procedures used in this study were visual acuity, subjective and objective refraction, accommodation status using the monocular estimation method (MEM), pupillary examination, evaluation of the extraocular muscle mobility, cover tests, and a detailed fundus examination using a direct ophthalmoscope. Visual acuity for distance (6 m) and near (40 cm) was evaluated using the Snellen number charts. Refractive status of the participants was obtained through static retinoscopy which was then refined using subjective refraction techniques. Refractive errors were classified as myopia ≥−0.50 D, hypermetropia as ≥+0.75 D, and astigmatism as ≥+0.50 D. Amblyopia was defined as the condition where there were at least three line differences in the visual acuity between the eyes that could not be explained by ocular defects other than anisometropia, strabismus, or large astigmatic error. In general, the visual acuity of the amblyopic eye was 6/60 or lesser. Children who need detailed evaluation were referred to the Pediatric Ophthalmology Department, Sankara Eye Hospital, Ludhiana, Punjab, India, where a detailed retinal investigation with indirect ophthalmoscope and anterior segment with slit-lamp biomicroscope was done.

 Results



Screening was conducted on a total of 118 children and young adults available in the school of the hearing impaired. Seventy (59.32%) children were male, and 48 (40.67%) children were female (age range: 6–25 years). The refractive status of the children was decided on the basis of results from both subjective and objective refraction. We were unable to perform subjective refraction in three participants as they neither read the Snellen visual acuity chart nor knew sign language to communicate. We found 71 (60.2%) of the screened children with some form of visual deficits, including binocular vision disorders such as phoria. The results of our screening are summarized in [Table 1].{Table 1}

Refractive error was found in 34 (28.8%) of our patient population. The rest (including mild hyperopia <0.75 D or astigmatism <0.5 D) were classified as having emmetropia. The distribution of the refractive error was hyperopia in 15 (12.7%) children, astigmatism in 6 (5.1%) children, and myopia (mild to moderate) in 15 (12.7%) children.

Binocular anomalies formed the majority of the visual deficits in our patient population. The cover tests, to look for latent strabismus (phoria) and manifest strabismus (tropia), revealed that 52 (44.1%) children had ocular deviations. One child (0.8%) had nystagmus and was unable to fixate for the cover tests. Amblyopia was present in four (3.4%) children. Exo or outward deviation was the common ocular deviation in 47 children (39.8%), and eso or inward deviation was present in five children (4.2%). Uncorrected manifest strabismus (tropia) was found in nine children, with eight (6.7%) having exotropia and one with esotropia. Accommodative status was also evaluated by MEM at 40 cm. A “lag” of accommodation between +0.25 D and +0.75 D is considered normal for all age group.[14],[15] Half of the screened children (n = 59) had normal accommodation status. Eight (6.8%) children had significantly higher lag than normal, and 51 (43.2%) children had lead of accommodation ([6],[10],[11] but is comparable to those reported in other studies.[9],[12] In comparison with a similar Indian population,[13] our prevalence rates are higher. However, unlike the seminal study by Gogate et al.,[13] we also measured the binocular status of our children including cover tests and MEM retinoscopy. The majority of our visual deficits can be classified as a binocular anomaly including phorias and accommodative discrepancies.

Our study matches the prevalence of significant refractive error (28.8%) as compared with the study by Gogate et al.[13] (18.5%), and hence we can explain the overall difference in visual deficits to the presence of binocular anomalies, which was not tested in the Gagote et al's. study. In our study, the distribution of the refractive error was 12.7% hyperopia, 5.1% astigmatism, and 12.7% myopia. Two of the children had complex astigmatism, i.e., myopia or hyperopia in addition to significant astigmatism. The rates that we report are similar to those reported by Ovenseri-Ogbomo et al.[6] Comparable studies from countries similar to India like Iran[16] and Turkey[17] show almost 52% refractive error out of 158 male deaf students and 29.8% out of 104 deaf children, respectively. In sub-Saharan Africa, the reported values are 31.9% for the prevalence of refractive error as obtained by Ovenseri-Ogbomo et al.[6] out of 243 deaf students in Ghana and 73.26% by Osaiyuwu andEbeigbe[12] in Benin. Although over a quarter of our screened population had significant refractive error, a majority of them had never undergone an eye screening or a checkup, which could have resulted in an early diagnosis and subsequent correction of the refractive error.

We found that a majority of our visual deficits (44.1%) can be broadly classified as binocular anomalies. This is significantly higher than that of the general population. For example, Ovenseri-Ogbomo and Assien[18] estimated the prevalence of ocular deviations to be 16.4% in the Ghanaian normal schoolgoing population. Our cover tests revealed that 43 (36.4%) of our screened children had latent strabismus and nine had manifest strabismus (7.6%). Surprisingly, the report of latent strabismus in deaf schoolgoing population is rare, and only one study[9] has reported an incidence of 11%. The prevalence of manifest strabismus has been reported to be around 9%–11%.[9],[19] Our study reveals a high percentage of children with lead of accommodation as revealed by MEM, the significance of such a high percentage is currently unknown, and further investigations including cycloplegic refraction are warranted to quantify these responses.

In our study, we also reported other ocular anomalies such as cataract, corneal opacities, and anterior-segment anomalies. One child was diagnosed to have a severe dry eye. Eight children had retinal disorders diagnosed with a direct ophthalmoscope. Our results are consistent with the studies reported by Mafong et al.[20] and Pollard and Neumaier,[10] but our rates of ocular abnormalities in deaf schoolchildren were higher than those reported in previous studies.[9],[11],[21] Our rates of ocular abnormalities were diagnosed within the screening protocol using a direct ophthalmoscope. There is a need for extensive visual screening in deaf schoolchildren including indirect ophthalmoscopy, which can potentially reveal more ocular abnormalities. In addition, we also propose the inclusion of cycloplegic refraction to accurately determine the refractive and accommodative status of these individuals.

In addition to the lack of an appropriate visual screening protocol in hearing-impaired schools, there is also a significant lack of awareness of visual problems among the children. In addition, communication barriers and an inability to express any visual difficulties contribute to difficulties in determining the well-being among these children. This is particularly true for children who are newly admitted to the school and thus are poor in sign language and communication. This study argues for a need of systematic and regularly scheduled visual screening and eye examination for this vulnerable group of people. Our report of prevalence and occurrences of ocular abnormalities in this study might have been underreported because eye examinations in schools have been conducted without other important evaluations such as stereopsis, vergence, and intraocular pressure evaluation, which are important in the diagnosis of other ocular disorders.

 Conclusion



Our study shows that schoolgoing hearing-impaired children and young adults have a significantly higher risk of having ocular morbidity. The combination of both the important senses of the human body is affected, which further exacerbates the problem. Hence, periodic eye examinations and vision screening are important in this hearing-impaired population.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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