Use of an arginine-restricted diet to slow progression of visual loss in patients with gyrate atrophy

Objective To quantify the effect of long-term reduction of plasma ornithine levelsthrough adherence to an arginine-restricted diet on visual function in patientsof all ages with gyrate atrophy of the retina and choroid. Methods A long-term observational study was conducted on 27 patients with gyrateatrophy, 17 of whom elected to comply with the arginine-restricted diet and10 who were unable to comply. The mean rates of change in the electroretinogramcombined response, electroretinogram flicker response, and kinetic and staticperimetry were determined. Results After mean follow-up of 13.9 years for the patients on the diet and14.1 years for those not on the diet, the mean rates of change for the dietgroup compared with those of the no-diet group were statistically significantlyslower for all outcome measures (age-adjusted P P = .06). Conclusions Adhering to an arginine-restricted diet so as to lower the plasma ornithinelevel below an average of 5.29 to 6.61 mg/dL (400-500 µmol/L) will slowthe loss of function as measured by sequential electroretinography and visualfield examinations.