Ocular axial length and corneal refraction in children with mucopolysaccharidosis (MPS I-Hurler).

BACKGROUND/AIMS: To assess corneal refraction and axial length in children with mucopolysaccharidosis I-Hurler (MPS I-H), treated early with stem cell transplantation (SCT), in order to establish possible causes of hyperopia.

METHODS

Clinical ophthalmological follow-up included keratometry and measurements of axial length.

RESULTS

Five patients, with SCT performed before 23 months of age, were examined. Median age was 8.2 years (range 5.2-10.5). Best-corrected decimal visual acuity was ≥ 0.5 (≥ 20/40 Snellen fraction) in seven of 10 eyes. High hyperopia, ranging from +4.0 to +9.0 spherical equivalents, was noted in all 10 eyes. Mild to moderate corneal opacities occurred in all 10 eyes. Optic disc areas, borders and cuppings were normal in all 10 eyes. No patient had glaucoma. Keratometry could be performed in five patients and demonstrated low values in the group ranging from 38.24 to 41.56 Diopters (D) right eye to 38.24-41.94 D left eye, which was significantly lower than the age matching reference material (p < 0.05). Axial lengths, available in five patients, ranged between 20.68 to 21.57 mm right eye and 20.52 to 21.38 mm left eye, which also was lower than the age matching reference material (p < 0.05).

CONCLUSION

Reduced axial length together with reduced corneal refraction is suggested to be causative to the hyperopia in patients with MPS I Hurler. Detection of refractive errors and prescription of eye glasses are important to avoid amblyopia.