Corneal Haze Update

Haze after surface ablations such as PRK can usually be prevented by limiting treatment to mild-to-moderate refractive errors and carefully using mitomycin-C (MMC). If haze does occur, most cases respond to topical steroids, though surgery may occasionally be necessary, according to Sharita Siregar MD.

“To avoid corneal haze, don’t perform PRK for high myopia or astigmatism more than 3.0 D or hyperopia more than 6.0 D,” she noted. “But if you must, you can still do it—but do not forget to use MMC intraoperatively.”

She explained that following PRK, epithelial injury from the laser releases inflammatory mediators and activates epithelial hyperplasia and keratocyte apoptosis. TGF-β then activates nearby keratocytes, turning them into myofibroblasts. Normally, these myofibroblasts undergo apoptosis after 24 days. However, if they persist, corneal haze can develop.

Risk factors for corneal haze following surface ablation procedures include high myopia or hyperopia exceeding +6.0 D, astigmatism greater than 3.0 D, stromal irregularities, persistent epithelial defects (such as anterior or epithelial basement membrane dystrophy), severe dry eye, exposure to ultraviolet light, and the omission of MMC during the procedure.

Haze can be graded based on the appearance of the cornea when viewed under the slit lamp using the scale (proposed by Fantes, et al.), Dr Siregar said. In the five-stage system, stage 0 indicates no haze, and stage 0.5 identifies trace haze that becomes visible under oblique slit lamp illumination. In stage 1.0, the haze does not interfere with the visibility of fine iris details. Stage 2.0 describes mild obscuration of iris features, while stage 4.0 signifies complete obscuration of the iris.

There are two types of haze following PRK, Dr Siregar noted. There is early-onset haze, which is the most common form and typically appears within three months, generally resolving within one year. There is also late-onset haze, which arises after three months and can persist for up to three years. Late-onset haze may significantly compromise vision and lead to corneal scarring, resulting in visual disturbances.

Dr Siregar is conducting an ongoing study involving 173 eyes from 139 patients who received myopic PRK. The results indicate that both early and late haze rates were greater in eyes with corrections exceeding -6.0 D compared to those with lower corrections. The study also found no significant difference in haze incidence based on whether MMC was applied for 20–60 seconds or 60–120 seconds.

For early haze, Dr Siregar recommends 1% prednisolone administered every 4 hours. Patients should be evaluated at the 2-week mark to assess treatment efficacy and complete a 12-week steroid regimen. For late haze, patients should receive 1% prednisolone every 2 to 3 hours as part of a 4-week course, with follow-up appointments scheduled at 2 and 4 weeks.

If haze persists, treatment depends on its depth. Superficial haze (less than 15 microns) can be managed with mechanical debridement, MMC, and 1% prednisolone every 4 hours. For deeper haze (more than 15 microns), PTK or PRK with 0.02% MMC is recommended. After PRK, patients should apply a bandage contact lens, topical NSAIDs, and preservative-free artificial tears and complete a 12-week course of topical steroids. Dr Siregar also advises patients to wear sunglasses and take vitamin C and D supplements.

Dr Siregar made her presentation during the 2025 ESCRS Annual Congress in Copenhagen.

Sharita Siregar MD is a cornea and refractive surgeon at Jakarta Eye Clinic (JEC) Eye Hospital and Clinics, Jakarta, Indonesia. sharita@jec.co.id