Disorders of the vitreous and retina
Congenital abnormalities (present at birth)
Minor abnormalities of the vitreous include vitreous cysts, which cause no visual impairment.
A more serious abnormality of the vitreous is persistent hyperplastic primary vitreous (PHPV), when the vitreous is replaced by a thick mass behind the lens). In this condition, which is unilateral, there is microphthalmia (an unusually small eye), an opacity (clouding) behind the lens and usually an associated cataract. Treatment varies according to the age of the child. If the abnormality is detected before 3 months of age surgery may be performed to remove the lens and vitreous with subsequent contact lens fitting and occlusion therapy (patching of the better eye) to prevent amblyopia (lazy eye), and in these cases good visual results may be obtained. If the abnormality is detected after 3-4 months surgery is not usually an option. With early surgery, prognosis can be improved but most children will have moderate to severe visual impairment in the affected eye. Occasional it is in both eyes.
Hamartoma, a benign tumour of the retina, usually presents in infancy or early childhood as either a squint or is identified at routine examination. The vision in the affected eye is usually poor unless the macula is unaffected. They do not usually progress as the child ages.
Retinal colobomas (cleft like defects) vary in size and the degree of visual impairment usually depends on the extent of coexistent optic nerve involvement.
Retinal dysplasia is a condition where there is failure of retinal and vitreous development which results in bilateral retinal detachment which is present at birth. It is associated with a number of syndromes, the most common of which is Norrie’s disease (causing learning disability and hearing loss). Affected children are also blind and have roving eye movements. Apart from surgery for any associated glaucoma, there is no specific treatment.
Angiomas (swelling of the blood vessels) of the retina may occur, usually in association with a syndrome called Von Hippel-Lindau disease (an hereditary disease causing vascular nodules in the retina). The angiomas vary in size and may present with blurred vision or be detected at routine screening. If treatment is required they usually respond well to laser therapy.
Acquired conditions
Retinopathy of prematurity
Retinopathy of prematurity (ROP) is a condition caused by proliferation (marked increase) of the retinal blood vessels which occurs in very premature, low birth weight infants and is more common in infants who have received treatment with high concentrations of oxygen. In the majority, it is mild and undergoes spontaneous regression (reduction in symptoms) but in a small minority it may proceed to retinal detachment and blindness.
All infants at risk are screened by examination of the retina until about 36 weeks after birth.
Early stage disease (stage 1 and 2) usually regresses spontaneously but stage 3 disease requires treatment with laser to prevent progression. Stages 4 and 5 (subtotal and total retinal detachment) may be treated by surgical reattachment of the retina but the resulting vision is usually poor.
