# Pupil Dilation

## Overview

This module describes how to dilate pupils by instilling dilating drops into the eye.

## Indications

1. Dilated retinal examination

2. Certain ocular surgeries

3. Prevention of posterior synechiae formation such as in uveitis or hyphaema

4. Relief of ciliary spasm (pain relief)

5. Cycloplegic refraction

6. Amblyopia treatment

## Contraindications

1. Shallow anterior chamber
   Shallow anterior chamber

   Dilating the pupil in an eye with a shallow anterior chamber can precipitate closed angle glaucoma. Always do the eclipse test before dilating of the pupils. See step 2 of the procedure.

2. Anterior chamber intraocular lens
   Anterior chamber intraocular lens

   after cataract surgery

   or iris claw lens

3. Head injury, unconscious patients and patients in ICU
   Head injury, unconscious patients and patients in ICU

   This could interfere with the monitoring of patients where pupil dilatation could be an important sign.

4. Patients who need to see clearly after the examination such as driving or reading (exams)

5. Hypertensive patients in whom

   phenylephrine
   phenylephrine

   Cyclomydril is a combination of cyclopentolate and phenylephrine.

   is contraindicated

## Patient information & consent

Always verify your patient’s identity and obtain informed consent before proceeding.

### How do I explain this procedure?

“To see into the back part of your eyeball, I need to give you eye drops that will enlarge your pupil, the dark part of your eye. The pupil normally gets smaller when a light is shined into it, but these drops will allow the pupil to stay wide open, so that I can examine and work in this area.”

### What can my patient expect?

“I will put the drops in your eyes every five minutes until your pupil becomes large enough. The drops don’t sting, but it may feel like everything is very bright once the drops are in. You will also struggle to focus with your eyes. It will take 4-6 hours, or even up to a full day for you to see normally again.”

### What is my patient’s role?

“Let me know if you have any eye conditions that you know of, or high blood pressure. When I put in the eye drops, tilt your head back so that the drops don’t flow out of your eye. Once the drops are in, keep your eyes closed, or press on the inner corner of your eye. After this procedure, you will need someone else to drive you home, and you may have difficulty reading today. Wearing sunglasses may relieve the feeling of brightness.”

## Preparation

###

### Documentation

1. Patient notes

### Equipment

1. Alcohol-based hand rub

2. Short-acting mydriatic drops such as tropicamide or cyclopentolate

## Site and Positioning

Position the patient sitting with their head tilted back.

## Procedure

Follow medical asepsis without gloves.

1. Perform hand hygiene.

2. Perform the eclipse test: shine a light from the temporal side of the cornea while facing the patient. In normal patients, the entire iris should light up. If the nasal half of the iris is in shadow, do not dilate the patient’s pupil.

3. Use a finger or thumb to pull down the lower lid at the cheekbone.

4. Instil one drop into the inferior fornix.

5. Ask the patient to apply pressure with a finger 1 cm inferomedial to the inner corner of the eye.

6. Wait five minutes, then repeat the instillation, usually 2-3 times, until the pupil is dilated.

7. Record the completion of the procedure in patient notes.

## Troubleshooting

The eye is taking a long time to dilate.

Some patients’ eyes take longer to dilate and may need more rounds of eye drops, such as

- Patients with b​​rown eyes
- Diabetics
- Patients with previous uveitis
- Patients with pseudoexfoliation
- Older persons

## Risks

1. Adverse reaction to eye drops

2. Contamination of the eye drops bottle
   Contamination of the eye drops bottle

   Be sure not to touch a patient's eye with the eye drops bottle, and always check the expiry date before administration.

3. Acute closed angle glaucoma
   Acute closed angle glaucoma

   This is why it is important to perform the eclipse test first, to rule out a shallow anterior chamber.

## References

1. Pons J. How to Examine the Eye. In: Mash B, Blitz-Lindeque J, eds. South African Family Practice Manual. 2nd ed. Pretoria: Van Schaik Publishers; 2010: 134-137.

2. Labuschagne MJ. Ophthalmology examination/procedures. 2021.