Don’t panic: a red patch after SMILE is almost always a burst blood vessel, not a complication — and it clears up on its own within 1 to 3 weeks.
You wake up the morning after surgery, look in the mirror, and one eye looks bloodshot. Your mind jumps to the worst case. In reality, it’s usually just a small broken blood vessel from the suction step — painless, harmless, and something your body absorbs by itself. This page shows you exactly how to tell that apart from the rare redness that genuinely needs a same-day call, plus one thing you can do before surgery to lower your odds of it happening at all.
Key Takeaways
- A painless red patch is usually a broken blood vessel, not an infection or a warning sign.
- It clears in 1 to 3 weeks on its own, turning yellow before it fades.
- SMILE causes fewer of these than LASIK, because it uses gentler suction.
- Pain, discharge or worsening redness needs a same-day call. Infection after SMILE is rare but serious.
- Redness can rarely appear weeks later, not just in the first few days — don’t assume it’s unrelated to your surgery.
| Your Question | Short Answer |
|---|---|
| Is redness after SMILE normal? | Often yes, if it’s painless |
| How long does it last? | Usually 1 to 3 weeks |
| Does it affect my vision? | No, it sits on the surface of the eye |
| When should I worry? | Pain, discharge, or blur alongside redness |
The Facts Behind the Advice
SMILE uses gentler suction than older LASIK lasers, which is part of why redness and bruising are less common. Here’s what the published data actually shows.
| Verified fact | Why it matters for your eye |
|---|---|
| A broken blood vessel (subconjunctival hemorrhage) occurred in 0.67% of SMILE cases in a 3,004-eye study | Uncommon, but it’s the redness cause you’re most likely to see |
| These broken vessels clear in 1 to 3 weeks, turning yellow first | Matches what most SMILE patients notice |
| Chronic dry eye affects 15–20% of SMILE patients past 6 months, versus 36–48% after LASIK | SMILE’s gentler suction preserves more corneal nerves |
| Infectious keratitis after refractive surgery affects about 4 in 10,000 eyes; only around 10 SMILE cases are published worldwide | Serious, but genuinely rare — this is what the emergency table below is for |
| Diffuse lamellar keratitis (DLK), an inflammation some assume only follows LASIK, showed up in 0.5% of eyes in a 5-year SMILE study | Explains why redness can appear well after the first week, not only in the first few days |
| Standard follow-up visits fall at 1–2 days, 1 week, 1 month and 2 months after surgery | Your redness gets checked at each of these anyway, even if it looks fine to you |
Sources: Wang et al., 2017; Mayo Clinic; a 2015 dry-eye comparison study; Soleimani & Haydar, 2021; a 5-year SMILE epithelial-complications study.
One Thing That Can Lower Your Risk Beforehand
Some broken blood vessels are simply bad luck from the suction step, but blood-thinning medicines and supplements (aspirin, fish oil, vitamin E, some herbal supplements) make them more likely and larger when they happen. Tell your surgeon about everything you take at your consultation — they’ll advise whether anything should pause beforehand. Don’t stop a prescribed medicine on your own.
Normal Redness vs. Something Else
Find the description closest to your eye, then read across.
| What You See | Likely Cause | What To Do |
|---|---|---|
| A flat, painless red or pink patch, no discharge | Broken blood vessel (subconjunctival hemorrhage) | ✅ Use your prescribed drops; it fades on its own |
| Mild overall pinkness for the first day or two | Normal healing and drop use | ✅ No action needed |
| Redness with gritty, dry-feeling eyes | Common early dry eye | ⚠️ Use lubricating drops between prescribed doses |
| Redness that comes back after seeming to clear | Rubbing or a new small vessel break | ⚠️ Stop rubbing; call if it doesn’t settle in a few days |
| Redness with pain, light sensitivity, or discharge | Possible infection or inflammation | ❌ Call your surgeon the same day |
| New redness or blur weeks after surgery, once you felt fully healed | Late-onset DLK, reported as late as month 6 in one study | ⚠️ Call your surgeon — don’t assume it’s unrelated to your surgery |
Sources: Mayo Clinic; Cleveland Clinic; Soleimani & Haydar, 2021 (fungal keratitis case, day 4 onset).
If your eyes water or sting on top of the redness, our page on nasal spray after LASIK covers a related everyday irritant question.
Caring for Your Eyes at Home
- Don’t rub. Rubbing is the single most common way a new broken vessel appears; see what happened when one patient accidentally rubbed their eyes after SMILE.
- Use your drops on schedule. They protect against infection and keep the surface comfortable.
- Skip the pool and hot tub for the time your surgeon gives you.
- Be gentle when washing up. Our guide on washing your hair after SMILE Pro covers keeping shampoo and water out of your eyes.
- Watch for vision changes, not just redness. If your eyesight itself seems unsteady, read fluctuating vision after SMILE.
- Blink on purpose during screen time. A quick blink-and-hold every 20 minutes keeps the surface from drying out and looking redder.
- Skip redness-relieving drops. They aren’t part of standard post-SMILE care and can mask a problem your surgeon needs to see.
If water or soap splashes in your eye
Rinse gently with clean water for a minute. If the eye still looks red or feels irritated afterward, that’s your cue to call — don’t wait to see if it settles.
When to Call Your Surgeon?
Call the same day if redness comes with any of these:
| Symptom With Redness | What It Could Mean | What to Do |
|---|---|---|
| Eye pain, not just discomfort | Inflammation or infection | ❌ Call your surgeon the same day |
| Yellow or green discharge | Possible bacterial infection | ❌ Call your surgeon the same day |
| Sudden blur or vision loss | Needs urgent assessment | ❌ Call immediately |
| Redness worsening after day 4–5 | Infection can appear this late | ❌ Call your surgeon the same day |
| Increased light sensitivity alone | Often normal healing, sometimes more | ⚠️ Mention it at your next follow-up, sooner if it’s severe |
Sources: Soleimani & Haydar, 2021; Indian Journal of Ophthalmology commentary on post-SMILE keratitis.
Not sure if what you’re seeing is bloodshot from strain or something more? See our guide to bloodshot eyes after laser eye surgery for the wider picture, or check how to clean your eyes safely without irritating them further.
Bottom Line
A red patch after SMILE is usually a small, harmless broken blood vessel that clears in one to three weeks without treatment. It becomes a same-day call only when pain, discharge or vision changes come with it. If you’re weighing SMILE against other options, our page on who isn’t eligible for SMILE is worth a read before your consultation.
Concerned about redness after your own surgery? Book a check-up with our team and we’ll take a look.
Frequently Asked Questions
Is red eye common after SMILE surgery?
It’s uncommon but not rare. Studies put broken-vessel redness at under 1% of SMILE eyes.
Will the redness affect my vision?
No. A broken blood vessel sits on the surface of the eye, not over the part that focuses light.
How long until it’s gone?
Usually 1 to 3 weeks, fading from red to yellow as it clears.
Is SMILE less likely to cause redness than LASIK?
Yes, generally. SMILE’s gentler suction and fewer corneal nerves cut mean less bruising and less dry-eye-related redness than older LASIK techniques.
Can I use eye drops for the redness itself?
Use only what your surgeon prescribed. Redness-relieving drops aren’t part of standard post-SMILE care.
What if only one eye is red?
That’s typical for a broken blood vessel, which usually affects one eye. If both eyes show pain or discharge together, call promptly, since that pattern has appeared in rare reported infections.
