Phototherapeutic Keratectomy With Mitomycin C for Recurrent Granular Corneal Dystrophy Under Femtosecond-Assisted Anterior Lamellar Keratoplasty

Phototherapeutic keratectomy

Phototherapeutic keratectomy is an excimer laser-based surgical procedure widely performed by corneal surgeons for treating anterior corneal stromal pathologies. Phototherapeutic keratectomy helps by ablating the corneal stroma, thereby improving corneal clarity and smoothening the surface. Transient discomfort and induced hyperopia from corneal flattening are the immediate postoperative concerns. The long-term course is often marked by the recurrence of original corneal pathology and corneal haze formation. Phototherapeutic keratectomy, however, allows for repeat stromal ablation for managing recurrences, as the corneal thickness permits, without affecting the outcome of future keratoplasty. Adjunctive methods such as topical mitomycin-C may be additionally used to reduce recurrence rates. Also, various masking agents such as carboxymethyl cellulose, sodium hyaluronate, and dextran are used in eyes with irregular corneal surface to allow for uniform stromal ablation. Overall, phototherapeutic keratectomy has provided corneal surgeons an additional surgical tool, particularly those residing in developing nations where the availability of donor corneal tissue is an important limiting factor.

Long-term clinical outcome of femtosecond laser-assisted lamellar keratectomy with phototherapeutic keratectomy in anterior corneal stromal dystrophy

Purpose

To evaluate long-term outcome of femtosecond laser-assisted lamellar keratectomy (FLK) with phototherapeutic keratectomy (PTK) in patients with anterior corneal stromal dystrophies.

Methods

A total of 10 eyes from seven patients who underwent FLK were included. The patients had suffered from recurrent corneal erosion or visual disturbance in anterior corneal dystrophies (five Avellino dystrophies and two lattice dystrophies). Planar-shaped lamellar keratectomy was performed using femtosecond laser. The amount of corneal excision was determined by the depth of corneal opacity. Additional PTK with mitomycin C application was performed for smoothening of corneal cut surface. The patients were evaluated with following parameters: uncorrected visual acuity, best-corrected visual acuity (BCVA), mean anterior keratometric value, corneal irregularity, corneal high-order aberrations (HOA) and the recurrence of corneal erosion.

Results

Mean duration of follow-up was 64 months (2.5–9.5 years). The BCVA improved more than two lines of Snellen chart at last visit. The changes of keratometric values were within ±1 D in eight out of 10 eyes. Corneal irregularities in central 5 mm cornea and the values of total corneal HOA in central 6 mm cornea decreased by 0.3–3.1 D and 0.01–2.2 µm, respectively. Corneal erosion did not recur in any of those patients during follow-up and corneal dystrophy did not recur in eight out of 10 eyes.

Conclusion

In anterior corneal stromal dystrophies, FLK with PTK can be an effective surgical option to improve VA through decreasing corneal irregularities and HOA, while minimising corneal curvature changes.