Fig. 2.

PA spectra in fixed and fresh brown porcine eyes. (a) Representative PA spectra for the scleral region (S), TM, anterior iris (AI), and posterior iris (PI) for fixed brown porcine eyes. Average PA spectra and standard deviations were also calculated for (b) the anterior iris and (c) posterior iris in multiple fresh brown porcine eyes. PA spectra appeared similar in fixed and fresh eyes. The measured PA spectrum (solid blue line) of the anterior iris was compared to the reported absorption spectrum^44,45 of melanin (dashed blue line). (c) The measured PA spectrum (solid orange line) of the posterior iris was compared to the reported absorption spectrum^46–49 (dashed orange line) of ${\mathrm{HbO}}_2$ to highlight a potential source of PA imaging artifacts following LLS regression analysis of spectroscopic PA datasets.