What haze is
After PRK the epithelium is removed and the laser is applied directly to the corneal surface. As the surface heals, activated cells called myofibroblasts can lay down disorganized collagen in the front stroma. That disorganized tissue scatters light and appears as a faint cloudiness under the microscope. Mild haze is invisible to the patient and fades. Significant haze reduces contrast, causes glare, and can regress the correction.
LASIK does not produce haze in the same way because the ablation happens under the flap, away from the healing epithelium. SMILE, likewise, has a very low haze rate.
Who is at risk
- High corrections, particularly above -6 D, where the ablation is deeper
- Hyperopic PRK
- Unprotected UV exposure in the first months
- Delayed epithelial healing, dry eye, or an interrupted drop schedule
- Darker irides and certain healing profiles show slightly higher rates in some series
How Colombian surgeons prevent it
Mitomycin C (MMC): a brief application of a very dilute antimetabolite to the ablated surface, standard practice for corrections above about -4 to -6 D and for any PRK over previous surgery. It dramatically reduced late haze rates when adopted in the 2000s. Ask whether MMC is used and at what threshold.
Steroid drop taper: a longer tapering course than LASIK, often 4 to 8 weeks, with pressure checks. Stopping early because your eyes feel fine is the most common patient-side cause of haze.
UV protection: this matters more in Medellín or Bogotá than in Toronto. At 1,500 to 2,600 meters near the equator, UV index is routinely extreme. Wraparound sunglasses outdoors for at least three months, and a hat, are not optional. See UV protection after surgery and recovery at altitude.
Vitamin C: some surgeons prescribe oral vitamin C for a few weeks based on animal and small human studies; it is low-risk and inexpensive.
Timeline
Haze, if it occurs, usually shows between one and six months after PRK, peaks around three months, and then slowly fades over the following year. It is graded 0 to 4 at the slit lamp. Grade 1 is common and harmless. Grades 2 and above affect vision.
Treatment when it happens
- Intensified topical steroids for early haze
- Time, as most haze clears within 12 to 18 months
- For persistent visually significant haze, a surface laser polish (PTK) with mitomycin C
Why this matters for medical travellers
PRK haze appears after you are home. Arrange a local eye doctor before you travel, keep your steroid schedule exactly as written, and take the sunglasses seriously. If you notice glare or fading vision in the second or third month, get seen promptly and send the findings to your Colombian surgeon.
For the PRK procedure itself and who still needs it in 2026, read PRK in Colombia.
Frequently asked questions
Is haze permanent?
Rarely. Most haze fades within a year to eighteen months, and persistent cases can be treated with a laser polish.
Does mitomycin C have side effects?
At the very dilute concentrations and short exposures used in PRK, serious side effects are rare. Its long-term safety record is now over two decades.
Can I get haze after LASIK?
Essentially no. Haze is a surface-healing phenomenon; LASIK ablates under a flap.
Having PRK in Colombia?
We will connect you with surgeons who use mitomycin appropriately and give you a written drop schedule to take home.
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