Each glaucoma medication is prescribed at a certain frequency and recommended to be administered at certain times of the day. The rationale for this is to take into account the half-life of the drug in order to ensure that an effective dose of medication is consistently delivered to the eye to maintain a relatively low and consistent intraocular pressure.
Each drug is also recommended at certain times of the day in order to minimise the risk of side-effects and to ensure that the maximum efficacy of the drug coincides with the diurnal peak of intraocular pressure. For example, prostaglandins are routinely prescribed at night to minimise the risk of red-eyes side-effects during the day time, and to allow the maximum IOP lowering effect of the drug to be effective during the diurnal morning peak of IOP that occurs near sun-rise with the cortisol-peak that triggers your body to wake-up.
