Cerebral Visual Impairment in Children with Neurodevelopmental Delay

Cerebral visual impairment (CVI) is defined as vision loss resulting from post-chiasmatic damage, in the absence of damage to the anterior afferent visual pathways or ocular structures, or vision loss that is greater than expected for the degree of ocular pathology. CVI is the leading cause of childhood visual disability in developed countries and the relative prevalence is increasing due to successful management of childhood blindness resulting from cataract and retinopathy of prematurity. In addition, increasing survival of children with brain injury has contributed to an increased incidence of CVI. Among children with visual dysfunction Nielsen et al. (2007a) found CVI in 48 out of 97 children; this corresponds to 49.5 %. The most frequent aetiologies for CVI in the Linz study was perinatal hypoxia or hypoxia in preterm children (56.3 %), followed by morphological disorders of brain development (28 %). In ~30 % the aetiology of abnormal brain development was of prenatal origin, in ~60 % of peri-natal, and in ~10 % of postnatal origin. At the time of assessment, about 15 % of children were younger than 2 years; about 70 % of children were between 3 and 5 years old and about 15 % were older than 5 years. More than half of the children (55 %) showed optic nerve atrophy; about two-thirds suffered from epilepsy. Visual Acuity is commonly reduced in CVI but can be normal. Binocular visual acuity gives an indication of the limitations of visual function. Unilateral brain damage is associated with homonymous hemianopia, which may be complete or incomplete. Damage to the optic radiations superior to the lateral ventricles leads to lower visual field loss. Children with cerebral visual impairment commonly have bilateral lower visual field impairment if there has been superior periventricular damage affecting the visual pathways. Impaired ability to see multiple targets at the same time results in impaired attention. In addition, a disability to estimate depth, particularly for moving the feet through depth, can lead to injury. Perception of movement is subserved bilaterally by cerebral tissue called the middle temporal lobes, which are found anterior to the visual cortex. Damage to this area on both sides can lead to impaired or even absent perception of movement. Only the static visual world can be seen and appreciated. Children with dorsal stream dysfunction can show many features related to dysfunction in this area, which causes difficulty in handling complex visual scenes. Ventral stream dysfunction associated with difficulty recognizing faces is a common feature of damage in the temporal lobe territory. Ventral stream dysfunction associated with difficulty recognizing faces is a common feature of damage in the temporal lobe territory. Social Interaction: People in a crowd or in the distance, may bedifficult to recognise. It tends to be difficultty perform more than one task at a time like talking and walking. Some children get distressed or angry or may even react violently when other restless children in the class-room cause distraction and this may be misconstrued as ‘bad behaviour’. These features can be isolating for the child. A study was done to evaluate causes for profound visual impairment in children ≤3 years of age at a tertiary eye care center in Andhra Pradesh, India. It revealed the causes of visual impairment were CVI in 33%, a combination of CVI and ocular visual impairment (OVI) 11%, and OVI only 56%. Delays in different areas of development were seen with CVI (72.5%), which included motor delay (51.5%), cognitive delay (14.6%), speech delay in (2.9%), and delay in multiple areas of development (like combination of motor, cognitive, and speech delay) in (31.1%). The patients referred/recruited from paediatrics department with neurodevelopmental delay as well as walk in patients in Ophthalmology OPD with Neurodevelopmental delay will be selected for the study. After taking due consent from the parents/guardians of the children with diagnosed/suspected neurodevelopmemntal delay, they will be given the PQCVI(Parentral questionnaire for Cerebral Visual Impairment) and baseline demographic characteristics will be obtained. The scores of the questionnaire will be calculated by an ophthalmologist. If the score for the child is below 2SD compared with the age appropriate normative scores, the child will be given further age appropriate ophthalmological evaluation.The Parentral questionnaire in CVI which will be used produced reliable responses in children younger than 72 months. The rapid increase in scores before the age of 3 years supports the importance of early identification of CVI. Thus, the above studies point out that Cerebral Visual Impairment in Children is an underdiagnosed condition, has multiple etiologies and causes varied manifestations. The early detection and treatment is important for the better prognostic chances for the child.