Subnormal visual acuity syndromes (SVAS): albinism in Swedish 12-13-year-old children

Area of Science:

• Ophthalmology
• Genetics
• Pediatrics

Background:

• A field study in Sweden examined the vision of 12-13-year-olds as part of the DESAMI project.
• The study aimed to evaluate residual amblyopia, ocular disorders, and subnormal vision causes in children born in 1985.
• This paper focuses on clinical and VEP data for children with uncorrected visual acuity of 0.8 or below, or unexplained visual disturbances.

Purpose of the Study:

• To evaluate the prevalence of residual amblyopia and ocular disorders in Swedish children.
• To investigate the etiologies of subnormal vision and normal visual parameters in this age group.
• To present clinical and VEP data for children with subnormal visual acuity or pathological visual states of unknown cause (SVAS).

Main Methods:

• 1046 children were examined; 76 were referred to a pediatric ophthalmologist.
• 18 children with unclassified visual disturbances underwent further ophthalmological examination and VEP recordings.
• VEP (visual evoked potential) was used to detect asymmetric responses indicative of albinism.

Main Results:

• Twelve children attended a second examination, with VEP recorded from 10.
• Nine children exhibited iris translucency, and seven showed asymmetric VEP, classifying them as albinos.
• VEP responses were normal in three children, showing symmetry without other abnormalities.

Conclusions:

• The study indicates a high prevalence of albinism in Sweden, approximately 100 times higher than previously reported.
• This prevalence may suggest a unique form of heredity with genetic contributions to albinism in the Scandinavian population.
• Electrophysiological examinations are vital for diagnosing albinism and excluding neurometabolic conditions in children with SVAS.