Subhadeep Das, M.Optom
Senior Training Manager (Malaysia), Vision Science Academy
Lecturer of Management and Science University, Malaysia.
Vision Science Academy Exclusive
Brain-related visual impairment is a loss of vision not primarily due to any defect in the eye, but due to some morphological or physiological abnormality in the cerebral cortex. Normally, the visual signals travel through the optic nerves to the brain where those signals are transformed into vision but in this disorder, visual cortex fails to assess and analyse the signals, and hence, fails to transform them into an image (Kozeis, 2010). It commonly affects the paediatric age group but can also be found in adults.
Clinical Manifestations
Following are a few notable manifestations of brain-related visual impairment (Kozeis, 2010):
(1) Poor visual recognition of faces and objects
(2) Inability to differentiate objects in time and space
(3) Staring into empty space
(4) Unable to respond to visual stimuli
(5) Loss of certain eye reflexes
Causes
A few potential pathophysiological mechanisms are discussed below:
(1) Disruption in blood supply Brain-related visual impairment may be caused by any pathological event which can alter its vascular supply e.g., ischemic, or haemorrhagic stroke.
(2) Raised Intracranial Pressure Hydrocephalus is a condition in which fluid builds up into the ventricles of the brain and causes pressure-related injury to the cortical structures.
(3) Infections Any severe infection, such as meningoencephalitis, can potentially inflict visual centres and lead to an agonizing visual impairment.
Diagnosis
(1) Clinical History A doctor can take a detailed history of the patient to rule out certain common causes which may lead to brain-related visual impairment.
(2) Examination A detailed examination of the eye and neurological system can be performed by either an ophthalmologist or a neuro-ophthalmologist to diagnose visual defects.
(3) Radiological investigations A doctor can also advise an MRI or a CT scan with the help of which one can pinpoint the area where there is certain pathology or the defect which is causing sight impairment (van Genderen, Dekker, Pilon, & Bals, 2012).
Treatment
There is no proper cure for brain related visual impairment but rehabilitation and education are necessary to slow the progress of the disease and can prevent the complications that can arise (Dutton & Jacobson, 2001). Certain experts believe that it is a condition that can heal on its own. As this condition mostly affects the children, it is very important to have trained and skilled teachers to ensure a quality education for such children. As soon as the diagnosis is confirmed, an urgent referral should be made to the authorities that have been assigned the duty to cope with the problems faced by these children. Specific recommendations based on the measurements of the visual function like visual acuity and visual field should be provided to the parents, teachers, and therapists. The teachers of the visually impaired children should assess the broader, functional visual abnormalities and in conjunction with the therapist, should devise a proper intervention plan. Additional support services such as an assistance for non-verbal learning disabilities, should be provided. Moreover, services of an instructor for mobility should be provided to those children who suffer from an impaired spatial orientation.
References
- Dutton, G. N., & Jacobson, L. K. (2001). Cerebral visual impairment in children. Seminars in Neonatology, 6 (6),477- 485. doi:https://doi.org/10.1053/siny.2001.0078
- Kozeis, N. (2010). Brain visual impairment in childhood: mini review. Hippokratia, 14 (4), 249-251. van Genderen, M., Dekker, M., Pilon, F., & Bals, I. (2012).
- Diagnosing Cerebral Visual Impairment in Children with Good Visual Acuity. Strabismus, 20 (2), 78-83. doi:10.3109/09273972.2012.680232
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