Unexpected visual gain with gene therapy suggests new areas for research

A pseudo-fovea develops in the gene-therapy treated eye of a patient in a Leber’s Congenital Amaurosis trial. The authors show analysis of this region of cone function outside the fovea and compares it with the early fovea gain seen in the other patients in the trial.

“The unexpected late emergence of visual gain in [this] patient to spatially coded and sustained stimuli and a coincident change in preference for fixation from the fovea to the treated retinal region suggest a slow development of a pseudo-fovea and an underlying experience-dependent plasticity of the adult visual system. These results raise the possibility that this gene-based therapy may further improve visual function in an unexpected and useful way in previously untreatable congenital blindness.”1

1) Cideciyan AV, Hauswirth WW, Aleman TS, Kaushal S, Schwartz SB, Boye SL, Windsor EA, Conlon TJ, Sumaroka A, Roman AJ, Byrne BJ, Jacobson SG. Vision 1 year after gene therapy for Leber’s congenital amaurosis.  N Engl J Med. 2009 Aug 13;361(7):725-7.