Researchers in the Netherlands have devised a set of clinical criteria to distinguish albinism from other conditions with similar ocular features. The set of major and minor criteria was a result of a study that described the phenotypic spectrum of a large cohort of albino patients and investigated the relationship between the ocular abnormalities and visual acuity (VA).

The major criteria include:

  1. Foveal hypoplasia grade of two or more
  2. Misrouting
  3. Ocular hypopigmentation, either iris translucency or fundus hypopigmentation grade two or more

The minor criteria include:

  1. Nystagmus
  2. Hypopigmentation of skin and hair
  3. Fundus hypopigmentation grade one
  4. Foveal hypoplasia grade one

The retrospective cohort study of collected clinical, genetic and electrophysiological data of 522 albinism patients found that only their foveal hypoplasia grading scheme, based on spectral domain optical coherence tomography (SD-OCT) images, correlated best with VA. Iris translucency, fundus pigmentation and misrouting grading schemes were not able to predict VA. The VA of the cohort varied from -0.1logMAR to 1.3logMAR.

Researchers concluded that without an established set of criteria, a clinical diagnosis of albinism might be difficult to establish because none of the characteristics observed were consistently present in their cohort. This demonstrated the phenotypic heterogeneity of the condition. The study also determined a prevalence of albinism in the Netherlands of at least 1:12,000.

Kruijt CC, de Wit GC, Bergen AA, Florijn RJ, Schalij-Delfos NC, van Genderen MM. The phenotypic spectrum of albinism. Ophthalmology. August 8, 2018. [Epub ahead of print].