eye care support

Pupil Dilation

The pupil is the opening in the centre of the iris and its job is to control how much light enters the eye.

Muscles in the iris (the coloured part of the eye) adjust the pupil size so the right amount of light reaches the retina, helping you see clearly. In bright light, the pupil becomes smaller and in dim light, it becomes larger.

Pupil size can also change with focusing, emotions, or pain. In most people, both pupils stay the same size even if one eye is exposed to more light than the other.

Why does my optometrist dilate my pupils?

During an eye examination, your optometrist looks through the pupil to assess the internal structures of the eye—especially the retina and optic nerve.

Because bright light from the examination instruments naturally makes the pupil constrict, it can limit the view. Dilating drops temporarily enlarge the pupil so the optometrist can:

  • Examine the retina more thoroughly
  • View the peripheral areas of the eye
  • Assess specific structures under higher magnification
  • This allows for a more complete and accurate eye-health assessment.
image5

What will I experience?

Most people—especially older adults—experience only mild or no noticeable change. Allergic reactions to dilating drops are rare. If you’ve reacted to drops in the past, let your optometrist know so they can take precautions.

Dilating drops take around 20 minutes to work. You may notice:

  • Blurred near vision
  • Increased sensitivity to light and glare
  • Occasionally, mild distance blur
  • These effects are temporary and usually wear off within about an hour.

 

AP

Pupil Dilation FAQs

Because dilated pupils let in more light, you may feel more sensitive to glare.

Helpful steps include:

  • Bringing sunglasses to your appointment
  • Waiting in the practice until your vision feels comfortable
  • Taking extra care when walking, especially on steps or uneven surfaces
  • Avoiding driving or operating machinery until your vision returns to normal
  • Arranging transport home if you are unsure how your vision will be affected

Although dilation can cause short-term inconvenience, it allows for a far more thorough assessment of your eye health.

It is especially important for people with conditions such as diabetes or other systemic health issues that can affect the eyes.

If you have any concerns after your appointment, your optometrist is always available to provide advice.