to glance at, to peep, glittering, to shine
睒 centers on a quick, furtive look: glancing at something, peeping, or catching a glittering shine that draws the eye briefly.
睒 combines 目 (eye) with 炎 (flame), likely suggesting the flickering, quick movement of a glance or a glittering shine. The exact historical development is uncertain.
An eye 目 beside flames 炎: picture a flickering fire catching your eye, making you glance or peep at its glittering light.
For セン, imagine a quick glance at a cent (coin) glittering in the firelight: cent -> セン, and the eye catches the shine.