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  5. FP1601 : Epidemiology of Children with Cerebral Visual Impairment at A Tertiary Care Center In...

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Dr. Niranjan Pehere, P10672, Dr. Pratik Chaugule

Introduction

Cerebral or cortical visual impairment (CVI) is an over-arching term covering a wide range of visual and perceptual visual impairments resulting from dysfunction, anomaly or injury to the retrogeniculate visual pathway (optic radiations, occipital cortex and visual associative areas) and oculomotor control.1CVIhas recently become the commonest causes of visual impairment in children in developed countries.2,3,4, 5, 6, 7, 8, 9, 10, 11. This is probably due to better management of avoidable causes of childhood blindness like cataract, glaucoma, ROP in children12 combined with improving survival of children who survive severe neurological damage during perinatal period.13 Improved diagnosis and reporting of this condition also may have led to this increase.14

 In developing countries like India increasing number of premature babies and babies who had stormy perianal period with brain injury are surviving. So CVI as a cause of visual impairment is on rise in such countries also.

Refractive errors and anomalies of accommodation are common in children with CVI.15,16 As a part of the syndrome they may have structural problems like cataract, coloboma, optic atrophy, retinal dystrophy etc.17,18 Retinopathy of prematurity (ROP) may be seen in association with periventricular white matter damage. Optic nerve hypoplasia and optic atrophy are associated with a wide range of brain disorders many of which impair visual function.19  Disorders of eye movement control are common in children with CVI, like: strabismus, nystagmus, unstable fixation, inaccurate fast eye movements (dysmetric saccades), deficient smooth pursuit movements and paroxysmal deviations, in which the eyes intermittently deviate upwards (most commonly). The problems with visually guided eye movements can partly be compensated for with head movements (in children who can control the head).1,20 

Since it is generally difficult to examine such children, some of these problems may get missed. Even if detected, child may not receive appropriate treatment thinking that it may not help. Above all many of these children do not receive an eye examination.

The purpose of this study was to understand common causes of CVI in our population and common ophthalmic problems that they have.

Material and methods:

A retrospective review of case records was done for children aged less than 16 years, who visited from January 2016 to December 2016 to The David Brown Children’s Eye Care Center, L V Prasad Eye Institute, Kode Venkatadri Chowdary campus, Vijayawada. Following details were noted for each case: age at presentation, presenting complaint, visual acuity, cycloplegic refraction, ocular alignment and motility, anterior segment and posterior segment findings. Significant refractive error was identified as per the preferred practice pattern by American Academy of Pediatrics with one modification for the hypermetropia, where we considered +3.0 diopter sphere as a significant error considering the fact that in children with developmental delay, low hypermetropias also become visually significant.21 

Results:

During the study period total 124 children were seen with a diagnosis of CVI. Eighty of them were boys and 44 were girls. Median age was 3 years (mean 5.24, SD 4.61). Fifty six (45.16%) were aged less than 2 years, among them 36 (29.03%) were infants.

The presenting complaint in majority (95 children, 76.61%) was poor vision. Fourteen (11.3%) presented for deviation of eyes (squint). White reflex from eyes (leukocoria) was noted by parents in 3 cases (2.42%). Some of the uncommon presenting complaints were frequent fall or bumping into things on the floor while walking (6), difficulty in walking up and down the stairs (3), slow visual response (1), inaccurate reach out to objects (1)

The most common cause of CVI in our group was hypoxic ischemic encephalopathy (HIE) seen in 50 cases (40.32%).  The second group was of unknown etiology 40 cases (32.26%). Sixteen children (12.9%) had epilepsy. History of neonatal seizures was present in 24 cases (19.36%). Other uncommon causes included neonatal hypoglycemia (4 cases, 3.23%), meningitis (3 cases, 2.42%), hydrocephalus (3 cases, 2.42%), stroke (4 cases, 3.23%),

Fifty four(43.55%) of them were referred by Pediatricians. Eighty four (67.74%)of them were born at term and 40(32.23%) were born prematurely. There was history of difficulty in breathing/delayed birth cry in 71 (57.26%) of them. Mean birth weight was 2.53kg (SD 0.76).

Sixty one children (49.2%) had strabismus. Thirty nine of them had exotropia (mean deviation 36.2prism diopters) and 22 had esotropia (mean deviation 29.25prism diopters).  Nystagmus was found in 9 children (7.3%).

We found significant refractive error in 62 (50%) children. Compound myopic astigmatism was the most common refractive error seen in 44 children (35.48%). Five of them (4.03%) had high myopia (>-6.0DS) , 6(4.89%) had high hypermetropia (>+5.0DS) (4 following cataract surgery).Insufficiency of accommodation was present in 15 (12.1%) children as assessed by dynamic retinoscopy. Four of these children were wearing glasses atthe time of presentation.

The most common anterior segment anomaly found was cataract in 5 (4.03%) children (all bilateral, 7 total, 2 anterior subcapsular, 1 visually insignificant). One child had bilateral lower lid coloboma and one child had oculocutaneous albinism. The most common posterior segment anomaly found was optic atrophy seen in 40 cases (32.26%).

Visual fields could be assessed in by either automated perimetry (Humphery visual field), confrontation test and other tests like few of the behavioral and play based tests that we use in our clinic. By these lower visual field defects were most common seen in 12 (9.68%) and hemifield defects were seen in 2 (1.61%) patients.

Seventy-one children (57.26%) had delay in one or more areas of development (motor delay in 49, speech 28, cognitive 20 and global delay in 29,).

Discussion: 

The most common cause of CVI in our series was hypoxic ischemic encephalopathy, majority of children were aged less than 2 years and had delay in multiple areas of development. About half of them had significant refractive errors, insufficiency of accommodation and strabismus. Five of them had cataract which required surgery. But none of these issues were known to the family. This highlights the need for regular and comprehensive eye examination of children brain damage.

Our findings are in accordance with previous studies which have reported prevalence of refractive errors in such children being in the range of  10-60% .2-12Hypoaccommodation is frequently under-diagnosed due to lack of awareness. Our data shows that   12% of them have it, hence it should be actively looked for in every child with CVI. These are easily treatable ocular problems which should be picked-up earlier in life to avoid amblyopia. But often such children do not receive a comprehensive eye examination, since they are unable to cooperate well and it is time consuming. In addition, it may be perceived that the correction of refractive correction or performing cataract surgery may not benefit the child due to his neurological condition, which is incorrect, and in fact its like adding an avoidable disability on top of a pre-existing disability. We feel that due to these issues, almost all of our patients did not get a complete eye examination and consequently did not get appropriate help for their problems before. Hence there is an acute need to create awareness about this in ophthalmic fraternity.

The fact that majority of these children are aged less than 2 years and have delays in multiple areas of development along with vision, there is a need for pediatric ophthalmology units to equip themselves with necessary skills and facilities to manage these children. Usually such learning experience not available during majority of the post-graduate and fellowship training programs. That may make them under confident while dealing with such children. So there is a need to include this also as an integral part of all ophthalmology training programs, looking at the increasing prevalence of children with neurological issues.

Vision is one of the multiple issues that these children have. And most of the skills involved in those issues are again vision dependent. It is important that the experts handling those issues understand how the child sees. Hence it would be most ideal for an ophthalmic department to have experts dealing with motor, speech and cognitive delay also to give a comprehensive service to these children under one roof, without having them to move from one place to another. This may sound like going beyond the formal scope of an ophthalmic service, but that would be the most suitable way to go for such children, we believe.

References

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