OCT of Bbs1M390R/+ control (no phenotype, SVEV129 background), versus Bbs1M390R/M390R TUDCA-treated, versus Bbs1M390R/M390R untreated control mice, all at age P120. (a) Control and (b) TUDCA-treated Bbs1M390R/M390R and (c) untreated Bbs1M390R/M390R mice. The retina was slightly thicker (0.161 mm vs. 0.152 mm), and the inner and outer nuclear layers were slightly wider and better defined in the OCT of the TUDCA-treated retina. On high magnification, the bright line representing the external limiting membrane (ELM) was better preserved in the TUDCA-treated retina.