It is recommended to take glaucoma eye drops at night because this is when the natural pressure inside the eye, called intraocular pressure (IOP), is typically highest. Glaucoma eye drops are used to lower IOP, which can help to slow or prevent damage to the optic nerve. By using the eye drops at night when the IOP is highest, the medication is able to provide the maximum benefit in reducing pressure and protecting the optic nerve. It is likely that the eye pressure is higher at night due to a person’s reclined position. One study showed an average increase of 2 points in intraocular pressure when a person is inclined in comparison to when they are sitting. This posture related increase in intraocular pressure is likely from an increase in the episcleral venous pressure.
Not All Glaucoma Drops Are Taken At Night
It is important to note that the instruction to take glaucoma eye drops at night is usually only for two types of drops. One of these drop categories is called a prostaglandin analogue or a PGA. Examples of prostaglandin analogues are latanoprost, bimatoprost, and travoprost. Another drop that is commonly recommended to take at night is called netursadil. This is in a class of medications that are called rho kinase inhibitors. The above medications each last for approximately 24 hours which is why the dosing for them is once daily.
Other types of glaucoma drops like timolol and brimonidine are usually taken twice a day and ideally should be taken 12 hours apart. This is because each one of these drops has an effect that lasts 12 hours so it is important to re-instill the medication into your eye as its effect is wearing off. This will help patients with glaucoma to maintain great IOP control throughout the day.
What If You Forget To Take Your Eye Drop At Night?
Some patients have difficulty taking glaucoma eye drops at night due to their work or life schedule. If you notice that you are frequently forgetting to put your medication in your eye at night, talk to your doctor about changing the time of day that you take the medication. While it is the most helpful to take the medication before you sleep at night, your doctor may say that it is okay to take the drop at any time during the day just as long as you are consistent. While this is not ideal, some medication is better than no medication. If you really are unable to remember taking your eye drop, then ask your ophthalmologist about SLT laser. This laser can help to lower the pressure of the eye and may be able to replace the need for an eye drop.
Related: What Is A Glaucoma Specialist?
Why Take Glaucoma Eye Drops At Night: Summary
The pressure in your eye is usually higher when you are reclined. This natural IOP spike or increase can be blunted by taking certain glaucoma medications at night. However, if you are finding it too difficult for your schedule, talk to your doctor to find a solution. It’s important for the health of your eyes to do your best to take the eye drops as directed by your ophthalmologist.
Arora N, McLaren JW, Hodge DO, Sit AJ. Effect of Body Position on Epsicleral Venous Pressure in Healthy Subjects.Invest Ophthalmol Vis Sci. 2017;58(12):5151-5156.