Albinism: Its implications for refractive development

Citation
Cf. Wildsoet et al., Albinism: Its implications for refractive development, INV OPHTH V, 41(1), 2000, pp. 1-7
Citations number
43
Categorie Soggetti
da verificare
Journal title
INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE
ISSN journal
01460404 → ACNP
Volume
41
Issue
1
Year of publication
2000
Pages
1 - 7
Database
ISI
SICI code
0146-0404(200001)41:1<1:AIIFRD>2.0.ZU;2-4
Abstract
]PURPOSE. Albinism involves the mutation of one or more of the genes associ ated with melanin synthesis and has many ramifications for vision. This stu dy focuses on the refractive implications of albinism in the context of emm etropization. METHODS. Refractive, biometric, and visual acuity data were collected for a group of 25 albino individuals that included the following: 18 oculocutane ous (13 tyrosine positive, 5 tyrosine negative); 7 ocular (2 autosomal rece ssive, 5 sex-linked recessive). Their age range was 3 to 51 years. All exhi bited horizontal pendular nystagmus. RESULTS. There were no statistically significant differences relating to al bino subtype for any of the measured parameters. All the subjects had reduc ed visual acuity (mean: 0.90, logMAR) and overall, there was a bias toward hyperopia in their refractive errors (mean: +1.07 D). However the refractiv e errors of the group covered a broad range (SD: 4.67 D) and included both high myopia and high hyperopia. An axial origin to the refractive errors is implied by the high correlation between refractive errors and axial length s. Refractive astigmatism averaged 2.37 D and was consistently with-the-rul e and highly correlated with corneal astigmatism, which was also with the-r ule. Meridional analysis of the refractive data indicated that the vertical meridian for hyperopic subjects was consistently nearer emmetropia compare d to their horizontal meridian. Myopic subjects showed the opposite trend. CONCLUSIONS. The overall refractive profile of the subjects is consistent w ith emmetropization being impaired in albinism. However, the refractive err ors of hyperopic subjects also can be explained in terms of "meridional emm etropization." The contrasting refractive profiles of myopic subjects may r eflect operational constraints of the emmetropization process.