. The mucopolysaccharidoses (MPS) are a group of rare lysosomal storage disorders characterized by the accumulation of glycosaminoglycans in several tissues and organs. This accumulation results in an array of clinical manifestations and premature death in severe cases. Ocular problems are very common in children with MPS and may involve the cornea, sclera, trabecular meshwork, retina, optic nerve and also the posterior visual pathways. The aims of this study are to give an overview of ocular problems in MPS and to provide clinical guidelines for paediatric ophthalmologists for early diagnosis and management of ocular manifestations in children with MPS. Diagnostic problems may arise in children with severe corneal clouding, hampering visualization of the fundus. Intraocular pressures may be falsely high, even leading to suspicion and unnecessary pressure‐lowering treatment. Simple interventions such as the use of prescription glasses or photochromatic glasses can considerably improve quality of life in children with MPS.

. 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.

Lens opacities or cataract were more common in children or adolescents with malignant disease and after conditioning with irradiation. Regular ophthalmological follow-up is important after HSCT for early intervention to avoid amblyopia.