Dilation of pupils is necessary during a routine eye check up as it helps see the inner parts of the eye better. This helps in identification, prevention and treatment of the inner eye conditions affecting the optic nerve and retina.
Dilation of pupil means opening or expansion of the pupils, which happens when the iris grows bigger to let in more light. Light passes through the pupils into the inner eye. The iris opens to widen the pupils when there is less light. However, when a person who is in a room with very dim light, comes out of the room to a bright light or day light, his pupils are wide open. This causes a lot more light to enter than the eyes can bear. That is why we tend to squint or close our eyes, when we come out of a room with dim light.
After checking the undilated eye, the doctor will administer eye drops to increase the size of the opening of the pupil.
Undilated Eye exam:
The doctor checks the following before dilating the pupils:
The back of the eye is checked only after dilating the pupil. The doctor will be able to see the optic nerve and the macula through an undilated pupil, but is not able to view fully. When pupil is dilated the entire retina becomes visible.
Dilation of pupils is done by using the eyedrops comprising of cyclopentolate, tropicamide, phenylephrine, etc. These medicines work by relaxing the muscles that help in focusing the eyes on an object.
Typically, it takes about 15-30 minutes to achieve fully dilated pupils. These drops may cause temporary stinging in the eye. Blurred vision can occur and lasts for about 4-6 hours and eyes may be more sensitive to bright light. Using sunglasses after the exam can help bear the brightness, but driving in certainly not advisable.
Conditions diagnosed with dilated eyes:
Eyes are checked after dilation for the following conditions:
Frequency of dilated eye exam:
Doctors generally recommend an annual, comprehensive exam with dilated pupils after the age of 50, earlier if there are risks such as family history, diabetes (type1 or 2) or others.