Oman Journal of Ophthalmology

EDITORIAL COMMENTARY
Year
: 2011  |  Volume : 4  |  Issue : 1  |  Page : 1--2

Cortical visual impairment in children - A new challenge for the future?


Meenakshi Swaminathan 
 Department of Pediatric Ophthalmology, Sankara Nethralaya, 18, College Road, Nungambakkam, Chennai - 600 006, Tamil Nadu, India

Correspondence Address:
Meenakshi Swaminathan
Department of Pediatric Ophthalmology, Sankara Nethralaya, 18, College Road, Nungambakkam, Chennai - 600 006, Tamil Nadu
India




How to cite this article:
Swaminathan M. Cortical visual impairment in children - A new challenge for the future?.Oman J Ophthalmol 2011;4:1-2


How to cite this URL:
Swaminathan M. Cortical visual impairment in children - A new challenge for the future?. Oman J Ophthalmol [serial online] 2011 [cited 2022 Aug 14 ];4:1-2
Available from: https://www.ojoonline.org/text.asp?2011/4/1/1/77654


Full Text

The prevalence of visual impairment in children with multiple disabilities is high; [1],[2],[3] it has been found to be 10.5% in children with developmental disabilities. [3]

Visual impairment reported in children with multiple disabilities may be secondary to ocular defects such as uncorrected refractive errors, [1],[3],[4] cataract, [2],[4] nystagmus, [2] retinopathy of prematurity (ROP), [2],[3] optic nerve atrophy, [2],[3],[4] or oculomotor abnormalities, or on account of cerebral defects such as cortical visual impairment (CVI), [2],[3],[4] delayed visual maturation (DVM), [5] or nystagmus. [2],[4],[6],[7] Identification of the cause of visual impairment is very important, to arrive at a clinical diagnosis.

The current definition of cerebral or CVI includes all visual dysfunctions caused by damage to or malfunctioning of the retrochiasmatic visual pathways in the absence of damage to the anterior visual pathways, or any major ocular disease. [8]

Cortical visual impairment has been recognized as being one of the most important causes of bilateral blindness, in the United States. [9] It is emerging as an important cause of blindness in the developing world too, with increasing survival of children who suffer perinatal hypoxia. These developmentally delayed and Cortical visually impaired children may have a wide range of visual deficits. Several perceptive visual functions such as face recognition, object recognition, motion processing, visual memory, orientation, visual spatial perception, and simultaneous perception may be affected in these children. Studies, however, have not looked at all of them systematically. [8] Vernier acuity has been found to be more affected than grating acuity. [10] There is some evidence that dorsal stream / magnocellular pathway deficits may be more common in children with CVI. [11] Studies have reported the finding of periventricular leukomalacia (PVL) on magnetic resonance imaging (MRI) of the brain, as an important anatomic finding in children with CVI. [12]

Visual impairment occurs more frequently among children with multiple disabilities. These children can have a combination of motor, cognitive, and visual dysfunction. It is important for pediatricians and ophthalmologists to look for and recognize CVI as a cause of visual development delay and visual dysfunction in all children with risk factors for perinatal hypoxia, including difficult labor and delivery, twin pregnancy, prematurity, and low birth weight, especially in the low socioeconomic group of patients, with limited access to health care and so on.

Recognizing CVI is the first step toward rehabilitation and prevention. These children need modifications in the examination techniques to assess vision and visual dysfunction. Conventional vernier acuity measurements are often not possible or give an erroneous picture. It is important to record grating acuity, which helps in follow-up. [13] Often qualitative visual acuity testing methods have to be used, to supplement the quantitative visual acuity recording methods. [6] Tests to detect the various types of perceptive dysfunctions need to be developed. These tests need to be adapted, taught, and made available to the ophthalmologists in the developing world.

Prognosis for improvement of visual impairment in CVI has also been an area of much debate. Although earlier studies had suggested that prognosis remains poor, longitudinal studies have found results to the contrary, suggesting improvement with time. Prevention will involve early recognition of the risk factors. Rehabilitation methods may need to be tailor made to each child. Each child with CVI is likely to have its own unique visual and motor deficit, necessitating an individualized approach.

References

1Van den Broek EG, Janssen CG, van Ramshorst T, Deen L. Visual impairments in people with severe and profound multiple disabilities: An inventory of visual functioning. J Intellect Disabil Res 2006;50:470-5.
2Flanagan NM, Jackson AJ, Hill AE. Visual impairment in childhood: Insights from a community-based survey. Child Care Health Dev 2003;29:493-9.
3Nielsen LS, Skov L, Jensen H. Visual dysfunctions and ocular disorders in children with developmental delay. 2 nd . Prevalence, diagnoses and aetiology of visual impairment. Acta Ophthalmol Scand 2007;85:149-55.
4Rogers M. Vision morbidity in Liverpool: Prevalence and morbidity. Arch Dis Child 1996;74:299-303.
5Casteels I, Spileers W, Missotten L, Casaer P. The baby with poor visual contact. Br J Ophthalmol 1998;82:1228-9.
6Huo R, Burden SK, Hoyt CS, Good WV. Chronic cortical visual impairment in children: Aetiology, prognosis, and associated neurological deficits. Br J Ophthalmol 1990;83:670-5.
7Jacobson L, Ygge J, Flodmark O. Nystagmus in periventricular leucomalacia. Br J Ophthalmol 1998;82:1026-32.
8Boot FH, Pel JJ, van der Steen J, Evenhuis HM. Cerebral Visual Impairment: Which perceptive visual dysfunctions can be expected in children with brain damage? A systematic review. Res Dev Disabl 2010;31:1149-59.
9Hatton DD, Schweitz E, Boyer B, Rychwalski P. Babies Count: The national registry for children with visual impairments, birth to 3 years. J AAPOS 2007;11:351-5.
10Skoczenski AM, Good WV. Vernier acuity is selectively affected in infants and children with cortical visual impairment. Dev Med Child Neurol 2004;46:526-32.
11Dutton GN. 'Dorsal stream dysfunction' and 'dorsal stream dysfunction plus': A potential classification for perceptual visual impairment in the context of cerebral visual impairment? Dev Med Child Neurol 2009;51:170-2.
12Casteels I, Demaerel P, Spileers W, Lagae L, Missotten L, Casaer P. Cortical visual impairment following perinatal hypoxia: Clinicoradiologic correlation using magnetic resonance imaging. J Pediatr Ophthalmol Strabismus 1997;34:297-305.
13Teller DY, McDonald MA, Preston K, Sebris SL, Dobson V. Assessment of visual acuity in infants and children: the acuity card procedure. Dev Med Child Neurol 1986;28:779-89.