Bardet Biedl refractive error
Reviewed by Ian Reekie

This is a retrospective cross-sectional study of 45 patients with genetically diagnosed Bardet Biedl syndrome. Patients with biallelic defects in any gene known to cause Bardet Biedl syndrome were eligible for inclusion. Patients underwent cycloplegic refraction and keratometry. The mean age of included patients was 16.4 years old and there were 26 male and 19 female patients. The study found the mean cylindrical refractive error on cycloplegic refraction to be 2.6 dioptres (standard deviation (SD) 1.5 dioptres) and the mean corneal astigmatism based on keratometry to be 3.7 dioptres (SD 1.0 dioptres). There was also a tendency towards myopia with a mean spherical prescription of -2.9 dioptres (SD 3.8 dioptres). The authors comment that several cell types within the cornea have primary cilia playing an important role in cell function, and this may connect corneal astigmatism to the pathophysiology of Bardet Beidl syndrome as a ciliopathy. The study had too few patients to determine if some causative genes produced more severe astigmatism than others. There was also a very wide range of corneal astigmatism (0.5–7.1 dioptres) without any report being made on the proportion of patients with moderate to severe astigmatism vs mild astigmatism. Nonetheless, this report highlights the important role that refractive error may play in visual impairment for Bardet Biedl patients, and the role of good refractive correction in the management of this condition.

Refractive errors in patients with Bardet Biedl syndrome.
Yavuz Saricay L, Baldwin G, Moulton EA, et al.
OPHTHALMIC GENETICS
2024;45(5):435–40.