How often do you recommend eye examinations in your patients with primary hyperoxaluria?

I think the risk of oxalosis and associated eye findings is low unless the patient develops CKD, since plasma oxalate remains fairly normal until CKD stage 3B or so. I would suggest that yearly eye exams are reasonable if the eGFR is < 45, and certainly if eGFR is < 30 or the patient is on renal rep...