What Drops Do to Your Eyes
Dilating eyedrops (called mydriatics) are used to dilate, or enlarge, the pupils of your eyes so that your eye doctor can see the inside of your eye in detail.
Dilating drops work in one of three ways:
When Drops Are Necessary
By temporarily paralyzing the muscle that makes the pupil smaller;
By stimulating the muscle that makes the iris (the colored part of the eye) widen; or
By preventing the pupil from adjusting for focus (called accommodation).
With your pupils dilated, your eye doctor can use special instruments to see the eye’s entire lens, which focuses light onto the retina (the light-sensitive tissue lining the back of the eye). The retina itself also can be seen, as well as the optic nerve, which sends signals from the retina to your brain where they are interpreted as images.
In addition to exams, dilating eyedrops are used for a variety of purposes. For some types of eye surgery, your ophthalmologist (Eye M.D.) will need to dilate your eyes. Sometimes, after certain types of surgery, it is important to use dilating drops to keep the pupil wide so that scar tissue won’t form. Your eyes may also be dilated to relax your lens’s focusing muscles so that your eye doctor can measure accurately for your glasses prescription.
Dilating drops are sometimes used in children who have amblyopia (lazy eye). Because the drops cause temporary blurry vision, they are used to blur the stronger eye, thereby forcing the child’s brain to use the weaker eye.
Duration And Dilation Effects
It usually takes 20 to 30 minutes for dilating eyedrops to begin working. People with light eye color (such as blue, green or hazel) are more sensitive and dilate faster than people with dark eye color (brown). With dilated pupils, you will be sensitive to light and you will find it difficult to focus on nearby objects. These effects can last for up to several hours, depending on the strength of the drop used and on each individual.
When you are going to have a dilated eye exam or procedure, you should bring sunglasses with you to minimize glare and light sensitivity when you leave your appointment. Dilating eyedrops cause a variable amount of blurry vision for an unpredictable length of time. The most common drops we use last between 3 to 5 hours. Your eye doctor cannot tell you how much your vision will be affected and for exactly how long. Because driving safely may not be possible after having your eyes dilated, you should make arrangements to have someone drive you after your appointment.
If you have any questions before or after a dilated eye exam or procedure, be sure to speak with your eye doctor.