Crystalline retinopathy in primary hyperoxaluria Omar S. Punjabi, MD, Kamran Riaz, MD, and Marilyn B. Mets, MD We present the case of a 2.5-month-old boy with type 1 primary hyperoxaluria and severe systemic oxalosis resulting in massive retinal crystalline deposition. Maculopathy was demonstrated by optical coherence tomography, and nystagmus was present. Electroretinography demonstrated retinal dysfunction, unusual in oxalosis. Case Report A 1-year-old Hispanic boy was referred to the oph- thalmology service at Children’s Memorial Hospi- tal for evaluation of crystalline deposits. He was the product of a full-term normal delivery and presented to his pediatrician at 2.5 months of age with a recent cough and nasal congestion followed by refractory vomiting. By 5 months of age, he was in renal failure. Renal ultrasonogra- phy revealed nephrocalcinosis and a dilated renal pelvis bi- laterally without a mass. Systemic workup detected elevated serum oxalate levels, and type 1 primary hyperox- aluria was confirmed after genetic testing and renal biopsy. Treatment included diet modification, Pyridoxine supple- mentation, and dialysis, followed by a liver transplant at the age of 9 months. On examination, the patient could fixate and follow objects with both eyes. Pupils were equal and reactive with- out an afferent pupillary defect. Extraocular movements were full, with no strabismus in primary gaze. Symmetric, intermittent, horizontal pendular nystagmus was present. Anterior segment examination was normal in both eyes. Dilated fundus examination revealed extensive retinal crys- talline deposits along and between the retinal blood vessels. RetCam (Clarity Medical Systems, Pleasanton, CA) images demonstrated bilateral crystalline deposition and macular whitening (Figures 1 and 2). Electroretinography (ERG) showed extinguished electrical activity to both photopic and scotopic stimuli, presumably due to basic retinal dysfunction secondary to crystalline deposition. The only waveform that was present was the high-intensity, white sco- topic waveform (e-Supplement 1, available at jaapos.org). Binocular preferential looking testing performed at the age of 13 months was equivalent to 20/380 (below normal for his age). A kidney transplant was performed at the age of 16 months. Dilated fundus examination at the age of 30 months showed a decrease in the intraretinal crystalline de- position in both eyes (Figure 2A and B), persistent retinal whitening in the right macula, and yellow luteal pigment in the left eye. Preferential looking visual acuity had im- proved to 20/130. Handheld spectral domain optical coherence tomography (Bioptigen, Durham, NC) showed massive retinal edema and subretinal fluid with FIG 1. Fundus photographs obtained at age 12 months. A, right eye: the optic disk is pink and has sharp margins. Retinal arteries are atten- uated and massive retinal crystalline deposition is present. The crys- tals also extended into the retinal periphery and appear to be both along blood vessels and in the retina between the blood vessels. B, left eye, showing a similar appearance, plus a central yellow area in the macula. Author affiliations: Department of Ophthalmology, Children’s Memorial Hospital, Northwestern University, Feinberg School of Medicine, Chicago, Illinois Submitted March 7, 2010. Revision accepted December 21, 2010. Reprint requests: Marilyn B. Mets, MD, 2300 Children’s Plaza, Box #70, Chicago, IL 60614 (email: mmets@childrensmemorial.org). J AAPOS 2011;15:214-216. Copyright Ó 2011 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 doi:10.1016/j.jaapos.2010.12.015 214 Journal of AAPOS