Common issues arising in children with visual impairment

Introduction

Visual impairment (VI), defined as a reduction of visual acuity and/or visual field loss, is diagnosed from the combination of history, physical examination, electrodiagnostic testing, genetic evaluation, and neuroimaging. Following counseling of the family regarding the diagnosis, the professional needs to provide support for vision habilitation. Over the past decades, many studies have focused on functional vision issues, which would broaden the definition of visual impairment. For the purpose of this chapter, the definition used for visual impairment will be defined by ICD-10 (2019 version, www.who.int/classifications/icd/icdonlineversions/en/ ).

Promotion of vision development

At birth, neonates are visually immature. Maturation can be influenced by many factors. In addition, the vision system is time-sensitive. Therefore, early identification of abnormal vision development is important, so interventions can be applied. Children with visual impairment in the first year of life have different vision and developmental trajectories. For the majority of these children, vision will improve, but in order to do so, the child requires opportunities to view and identify.

Normally, this process is spontaneous, but infants with VI must be encouraged to use their sight. In addition to limitations in vision, visual interaction can be reduced by defective eye movements, marked developmental impairment, or visual attention disorders. Although visual learning continues throughout life, the rate of acquisition of visual skills is greatest during infancy. The development and structuring of the visual brain is influenced by visual input. Ideally, the visual environment should be rewarding, meaningful, and increasingly complex – otherwise, there is a loss of opportunity to fully develop the visual potential. Visual activities leading to sustained attention can improve visual potential. It should start immediately after diagnosis. Professionals working with VI infants must understand the visual abilities. It is important to avoid repetitive visual stimuli, such as flashing lights, and to make interactions increasingly meaningful for learning. The facilitation of visual development can be carried out by family members throughout the day when the infant is alert.

Many children with significant congenital visual loss appear to have little or no vision during early infancy, but most develop useful sight later. There are two reasons for this:

1.
Visual acuity, fields, eye movements, accommodation, perception, and cognitive factors rapidly improve after birth.
2.
The vision may be so severely reduced by the combination of physiologic, ocular, or neurologic factors that children cannot use their vision spontaneously and experience delayed visual development.

Because the maturation of the brain and visual system is stimulus-dependent, encouraging these infants to use their sight is critical.

Early interventions

The habilitation (or rehabilitation) of children with visual impairment results from their physical, emotional, and intellectual growth responding to skilled, early intervention. The effect of visual loss and other disabilities on development is complex. A multidisciplinary approach is an effective way to deal with VI children. The team may include ophthalmologists, pediatricians, geneticists, nurses, psychologists, speech–language pathologists, audiologists, physiotherapists, and orientation and mobility specialists. Close cooperation between the professionals dealing with the VI child is important. When the parents are included as part of the team, they become more effective in the management of their children. The use of a developmental journal along with a structured approach has shown positive benefits. The parents should receive copies of reports relating to their child. In addition, the team should advocate for children with visual impairment, educate the community involved in the child’s care, and encourage participation in research activities.

The multidisciplinary team will consider many areas of child development. This, in turn, will allow the individual with visual impairment to be better able to participate in activities in the home, school, and community. In addition, these groups are often linked to several community organizations, which help to integrate individuals into varying activities, including sports and social events.

It is important to emphasize the role of the ophthalmologist, as most often they are involved in the identification and initiation of the intervention process. The ophthalmologist plays a key role in the optimization of the visual pathway through accurate diagnosis and medical management such as refraction. Vision has time-sensitive periods, which can have an impact on the visual development in infants.

Development in the child with visual impairment

Conceptual development

Visual impairment has a noticeable effect on cognition. This is more evident in the context of neurological dysfunction, as associated dorsal and ventral stream disorders lead to higher-order visual processing issues. Reduced vision may result in fragmented processing of information, as only a part of the object can be seen or felt at one time. The relationships to other objects may be lost. In addition, children with visual limitations often miss opportunities to be influenced by the environment. This may lead to limited interaction and exploration, particularly with objects outside their reach. As attention span in VI children is usually shorter than for sighted children, they require more structural support to understand concepts. So, visual limitations will influence perceptual and cognitive development. In addition, children with limited vision will have associated delays with manipulative abilities and concepts.

Given these features, these children may become passive and understimulated if experiences are not brought to them. Therefore, difficulties arise when they are assessed about their knowledge of their environment. They may have challenges in organization and verification of information. There are many other features that may affect concept development. These features include, but are not limited to, object permanence, causal relationship, patterning, classification, and relative sizes. Children with visual impairment have been shown to have challenges with maintaining their attention. As a result, more time may be needed to establish these concepts. This does not necessarily indicate poor cognitive ability, but insufficient opportunity to acquire the skills and information that would be normal for a sighted child. The development of visual motor skills, arrangement of objects in space, and constructive play are also affected. VI children often avoid activities such as construction toys, puzzles, and drawing. Making experiences available and encouraging them to use their residual vision is essential.

Motor development

VI children who are raised in a rewarding, stimulating environment provided by loving, informed parents who are supported by professionals, develop motor skills faster than those who are understimulated. Even infants with severe visual loss, reared under ideal circumstances, may experience motor delays. Often, there is early delay in hand utilization. Crawling and independent walking may begin late, whereas unsupported sitting and standing may be age-appropriate. Understimulated congenitally blind infants frequently develop generalized hypotonia with poor posture, delayed motor skills and poor coordination, and walk with a gait disturbance. It is the self-initiated mobility that tends to be problematic. When intervention is not started early, these problems become permanent. Moreover, physical fitness in older VI children is often poor from habitually reduced physical activity.

Blind infants without brain damage are usually quiet, passive, and require encouragement to move. They may not acquire skills through “incidental” learning, as do the sighted. Motor tasks such as sitting, pushing, pulling, jumping, and early aspects of orientation and mobility must be taught. Partially sighted children usually learn to move about normally and cannot be distinguished from the sighted, unless they are required to carry out balancing activities.

Similarly, dexterity-based tasks may be impaired, as children will require increased time to identify, handle, and manipulate objects. Using reinforcing cues such as a lighted object, sound or vibration may promote manual exploration. Often, objects that have a concrete understanding can be used to reinforce object differences, such as a spoon or cup.

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