Rabbi Rules on Wearing Photochromic Glasses on Shabbat

Rabbi Yigal Cohen, head of the Yabia Omer institutions and a member of the Chief Rabbinate Council, addressed the question of whether it is permissible to wear photochromic glasses, which darken in sunlight, on Shabbat. The discussion falls under the category of 'melachet tzovea' (the prohibition of dyeing or coloring) on Shabbat.

Rabbi Cohen ruled that wearing such glasses on Shabbat is permissible. He explained that the darkening effect is a natural chemical reaction triggered by sunlight and does not constitute an act of dyeing or coloring in the halachic sense. Therefore, it does not violate the Shabbat prohibition of 'melachet tzovea'.