A method for monitoring use of eye drops in user's eye. The method includes measuring temperature of ocular surface (OS) of user's eye, at first plurality of time instants within first time duration (FTD), prior to optical apparatus (OA) not being in use for predefined time period; generating first temperature trend (FTT), for FTD; measuring temperature of OS of user's eye, at second plurality of time instants within second time duration (STD), subsequent to OA being in use, wherein OA is brought to use after OA not being in use for predefined time period; generating second temperature trend (STT), for STD; determining change in temperature trend between FTT and STT; determining if change in temperature trend is greater than predefined value; and when it is determined that change in temperature trend is greater than predefined value, deeming use of the eye drops in the user's eyes.