Fig. 1.

A twenty-one year old male with mucopolysaccharidosis type I undergoing Laronidase enzyme replacement therapy.

A Color fundus photographs of the right and B left eye, showing slight foveal reddening, but no bull's’ eye macular appearance. Images are blurred by corneal clouding. C Optical coherence tomography (OCT) scanning (Cirrus, Zeiss, Germany) of the right, and D left eye showing subfoveal hyperreflectant material at the level of the external limiting membrane. The key OCT features of photoreceptor structure appear intact. Inset OCT cube views demonstrate in both eyes parafoveal thinning. E Multifocal ERG responses (Roland, Brandenburg, Germany) showing reproducible response only in ring 1 in the right eye (red arrow), and F no reproducible responses in the left eye. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)