Topographical retinal function in oculocutaneous albinism.
OBJECTIVE
Macular hypoplasia is the major ocular finding in albinism because it underlies reduced acuity and congenital nystagmus. Anatomic studies have shown a lack of foveal differentiation. However, functional anatomy of the macula in albinism is not known.


METHODS
Observational case reports.


METHODS
We measured the topology of the retinal response in two patients with oculocutaneous albinism by using simultaneous fundus monitoring and multifocal electroretinographs (ERGs). Stimuli consisted of a 103-hexagon array centered on the macula. Recording conditions eliminated nystagmus artifact.


RESULTS
ERG amplitudes were reduced only in the central 5 to 10 degrees compared with adult norms. When the response was scaled by stimulation area, multifocal ERG amplitudes were constant across all retinal eccentricities.


CONCLUSIONS
The results suggest a homogeneous density of cone photoreceptors across the central retina in albinism, consistent with anatomic studies showing arrest of postnatal macular development. Further normative data are needed to fully quantify macular development in young children.
Kelly
John P
JP
Division of Ophthalmology, Children's Hospital & Regional Medical Center, University of Washington Medical Center, Seattle, WA 98105, USA. john.kelly@seattlechildrens.org
Weiss
Avery H
AH
D016115:Albinism, Oculocutaneous / Q000503:physiopathology*; D002675:Child, Preschool; D004596:Electroretinography; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D012160:Retina / Q000503:physiopathology*