Pupil Size and Laser Eye Surgery

The size of your pupil can vary from 2mm to 8mm depending on the natural accommodative power of your eyes and whether you are in bright (2-4mm) or dim (4-8mm) light conditions.

 

While you might think the pupil is just a big black opening in the centre of your eye that gets bigger or smaller at any given time, the truth is your pupils are responsible for controlling the amount of light allowed into the eye.

 

Surrounded by the iris, which gives your eyes their colour, the pupils contract and relax depending on the intensity of outside light.

Why do pupils change size?

Your pupillary reflex is controlled by the autonomic nervous system in the body, which instructs the muscles in the iris to either constrict or relax depending on how bright or dark conditions are.

 

Dilator muscle: Shrinks the iris when in low levels of light. This makes the pupil appear larger in order to allow as much light as possible to shine on the back of the eye.

 

Sphincter muscle: Expands the iris when you find yourself in bright conditions, so the pupil contracts and less light can infiltrate your eye.

Why does pupil size matters when it comes to Laser Eye Surgery?

Pupils are normally equal in size, but there is a condition called anisocoria which is when one pupil differs in size from the other.

 

Some people naturally have larger pupils and sometimes certain medications can cause pupils to become larger, especially in dim lighting.

 

Taking an accurate measurement of a prospective Laser Eye Surgery patient is extremely important as some corrective procedures aren’t suitable.

 

During your free consultation, pupil size will be measured in dark conditions so that the pupil is fully relaxed and at its largest.

How larger pupils can react to Laser Eye Surgery

There is a greater chance of night vision being affected in patients with large pupils, which can cause glare, halos or starbursts.

 

However, advances in laser technology have adapted so that those with large pupils can undergo Laser Eye Surgery safely.

 

The WaveFront procedure in particular is ideal for larger pupils as a 3D map of the corneal surface is taken when the pupil is fully dilated.

 

Corrective treatment is then programmed to correct every error on the cornea without negatively affecting night vision ability.

 

To find out more about WaveFront or any other corrective procedure, book your free consultation on +353 1 223 8821.

More to Explore

Who can get KAMRA inlay lens?

10 Sep 2012
Read more

The Facts - Laser Eye Surgery Myths Busted!

02 Dec 2014
Read more

What you can do to treat your cataracts

02 Aug 2020
Read more

Laser Eye Surgery and Astigmatism

03 Nov 2013
Read more

Book a Free Consultation Today!

At your consultation we will answer all your questions, discuss finance options, and assess whether you are a suitable candidate for one of our life-changing, treatments. Consultations with our expert Optometrists are free and take approximately 1 hour at one of our nationwide clinics.
World’s Leading Technology
Laser Eye Surgery Lifetime Care Guarantee
Laser Health Insurance Discount
World-Renowned Surgeons
20% Tax Relief
0% Interest Free Finance
99% Of Our Patients Recommend Us
No Waiting List Guaranteed

Patient Reviews

Brahim Bouya
google
Brahim Bouya
June 12, 2026

Best decision I’ve made, highly recommend Optilase! My journey with Optilase actually started over a year ago with a free consultation. Due to the curvature of my eyes I wasn’t eligible for LASIK, but rather than turn me away, the team referred my results to the surgeon for advice and recommended I return in 12 months to check my vision was stable. That level of care and thoroughness from the very start really set the tone. A year later I came back, passed all the tests, and was approved for PRK. Every step of the process was explained clearly, the optician was precise and even gave practical tips like taking Omega 3 supplements to support recovery. On the day of surgery (30th April), I was nervous, but the team were incredibly reassuring from the moment I walked in. There were multiple checks, a detailed pre-op conversation with the surgeon, and a video walkthrough of the aftercare drops. By the time I went in, I felt fully prepared. The procedure itself took less than 2 minutes, I felt nothing. The technology is seriously impressive. Over a month on, my vision is transformed. It’s genuinely one of the best decisions I’ve ever made. If you’re considering laser eye surgery, don’t hesitate and don’t hesitate to choose Optilase.

Aoife C
google
Aoife C
June 12, 2026

Good experience, reassured during procedure and understood risks and all steps along way

Renata Gomes
google
Renata Gomes
June 2, 2026

I couldn't finish the process without leaving a review for this amazing team. Thank you all for helping me see so clearly without needing glasses. This month marks 3 months since I had LASIK, and it has truly been life-changing. Wearing glasses always bothered me because I enjoy sports, and even contact lenses were often uncomfortable. The whole journey started with Clare Hegarty at South William Street. Thank you so much, Clare, for your care and attention. As a Senior Optometrist, you gave me hope. At first, the process seemed almost too easy, which made me a little nervous, but it turned out to be one of the best decisions I have ever made. Thank you as well to Thomas Materman. Your clear, simple, and direct explanation of the procedure made me feel comfortable and confident throughout the process. Thank you to the entire Optilase team. Three months later, it feels as if I never had surgery at all—except that I can now see perfectly. I have experienced no negative side effects, and I am delighted with the results. I highly recommend Optilase to anyone considering LASIK surgery.☘️☘️☘️

Blaithin Cox
google
Blaithin Cox
May 30, 2026

Couldn't be happier with my experience of the Lasek eye surgery. I had consultations in St William Street and surgery in Carrickmines, staff in both clinics were friendly, professional, and excellent staff their job. I would recommend Optilase to anyone considering laser eye surgery.

Anne Beakey
google
Anne Beakey
April 29, 2026

Staff are lovely here and provide a great service

Shane Guihen
google
Shane Guihen
April 20, 2026

Couldn't recommend highly enough, everyone I dealt with, from the initial consultation, to the surgery and the after care were absolutely top class and a pleasure to deal with

Katie Corcoran
google
Katie Corcoran
April 13, 2026

Excellent service. I found optilase really great to deal with- they were so professional and well organised before and during the laser eye surgery. They were also very friendly and the aftercare was great.

Roisin Mitchell
google
Roisin Mitchell
April 7, 2026

I had a great experience and Optilase getting laser eye surgery, it was without a doubt the best money I ever spent and wish I did it years ago! I rave about it to anyone who'll listen. From my initial consultation to the surgery itself in Dublin and the aftercare in Galway I couldn't rate it highly enough. The staff were so professional, informative, friendly and attentative throughout the whole process. Extremely happy customer!

amnnau
google
amnnau
April 3, 2026

Got my PRK surgery with optilase couldnt be happier! I was cared for in each step even post surgery, give me a call or message if you need referral

Amy Phelan
google
Amy Phelan
April 2, 2026

Had such an amazing experience with Optilase in Cork. Such a brilliant team, they all made me feel so relaxed and explained everything so well. They reassured me so much on the day of my surgery, and I never felt rushed with any questions. I would highly recommend Optilase to anyone even considering laser eye surgery. I am the most nervous and skeptical person and it’s truly the best thing I ever did, there is honestly nothing to be worried about!! I had zero pain whatsoever and my vision was clear by that evening and 100% perfect the next morning, it’s truly amazing! Wish I got it done years ago. I have so much freedom now without contact lenses or glasses, it’s so hard to believe my vision is fixed!!

Helen Sanfey
google
Helen Sanfey
April 2, 2026

My experience has been amazing. Everything was super professional and I was handled with complete care. My vision is perfect now and has changed everything for me.

Chloe Kearney
google
Chloe Kearney
March 5, 2026

Had a consultation done today couldn’t fault the team at optilase the were very informative answer all the questions I had very quick and professional would definitely recommend

Lets Connect

Privacy CentrePolicy & ProceduresTerms & Conditions
Flexible Payment with
humm
Book a Free Consultation
crossmenuchevron-left