Some studies report that carbonic anhydrase inhibitors decrease ICC volume without clinically significant gains in visual acuity,2 10 while other studies have reported no morphological and/or functional benefits and spontaneous fluctuations in ICC volume.6 11 XLRS could be amenable to gene supplementation therapy as a monogenic disease linked to loss of function mutations in the RS1 gene. Here, RS1 is linked to intrahepatic cholangiocarcinoma.