Cortical visual impairment — formative SAQs

SAQ 1 (10 marks)

A 10-month-old girl born at 26 weeks gestation is reviewed because she does not reliably fix and follow or reach for toys held in front of her. She has spastic diplegia and turns toward the window light, sometimes ignoring her mother's face held close. Her external eye exam, red reflexes and dilated fundus are normal, with clear media and a healthy retina. ^[6]

Question: (a) What is the diagnosis, and what does the normal eye exam signify? (b) Outline the assessment and investigation. (c) Outline the habilitative management and the prognosis. (10 marks) ^[2]

Model answer

(a) Diagnosis and the normal-eye clue (3 marks). The most likely diagnosis is cortical visual impairment (CVI), in which reduced visual function arises from damage to the brain's post-chiasmal visual pathways and occipital cortex rather than from the eye. The extreme prematurity and spastic diplegia point to periventricular leukomalacia, and the paradoxical behaviours — light-gazing and ignoring near faces — fit the CVI profile. The normal eye exam is the central clue: clear media, normal red reflex and healthy retina mean the eye is structurally intact, so the visual difficulty must lie in the brain. The older term cortical blindness is avoided because she is not blind and her vision fluctuates; cerebral visual impairment is the preferred umbrella term. ^{[1] [2]}

(b) Assessment and investigation (4 marks). Confirm the eye is normal with a full ophthalmology assessment including cycloplegic refraction, to exclude a severe refractive error or optic nerve hypoplasia that could mimic CVI. Arrange MRI of the brain to identify the periventricular white-matter injury, confirm the cause and exclude a treatable structural lesion such as hydrocephalus. Use a structured assessment tool — the CVI Range (Roman-Lantzy) — to quantify her functional vision across the ten characteristic behaviours and establish a baseline. Combine these with the parents' account of how she uses vision at home, observing the fluctuation, the distance-versus-near pattern, and any field deficit, to build the functional profile that guides habilitation. ^{[9] [6]}

(c) Habilitative management and prognosis (3 marks). There is no drug or surgery for the injured cortex, so management is habilitative. The foundation is environmental modification: reduce visual clutter so she faces a plain background, present single high-contrast objects in her best field and at the preferred distance, control the lighting, and allow extra processing time. Build individualised visual stimulation using movement, colour and contrast to engage spared pathways, and coordinate the multidisciplinary team — ophthalmology, neurology and neurodisability, education and therapy — with a shared written plan across home and school. The prognosis is generally one of improvement through neuroplasticity over months and years, though residual deficits such as the lower-field loss and crowding intolerance usually persist and continue to shape learning. ^{[11] [7]}