Two-steps laser-assisted selective stroma transplantation

Selective stroma transplantation (STS) is a new type of keratoplasty that we have proposed for the surgical treatment of isolated stromal pathology. Due to the closed and intracorneal surgical technique, STS eliminates intraocular complications. This technique is sutureless, allows keeping the corneal surface intact, excludes complications related to corneal epithelialization, and optimizes the use of donor corneal material. At the same time, the indications for the operation are limited due to the low prevalence of isolated stromal pathology. Considering the advantages and prospects of STS, we have developed a two-steps laser-assisted technique of selective stroma transplantation to expand the indications for the operation, the indication for which is a prevalent pathology of stroma with involvement of the anterior corneal surface. Purpose. To present the technique of two-steps laser-assisted selective stroma transplantation and to evaluate short-term results in a series of clinical studies. Materials and methods. The operation was performed in 3 patients aged 44 to 61 (mean age 53 ± 6 years) with corneal stromal dystrophy with involvement of the anterior surface of the cornea. Before and after surgery, refractometry, visometry, biomicroscopy, photoregistration, keratometry, and optical coherence tomography of the cornea were performed. The interval between the first step (STS) and the second step (phototherapeutic keratectomy) ranged from 3 to 4 months and averaged 3,0 ± 0.4 months. After the second step of surgery, eye refraction, visual acuity, corneal thickness, and corneal transparency at the optical center were evaluated. The follow-up period was 10 ± 3 months (6 to 15 months). Results. No intraoperative or postoperative complications were registered. The cornea remained transparent throughout the entire follow-up period. Mean visual acuity increased from a preoperative mean of 0.16 ± 0.02 to 0.60 ± 0.04 at the time of the last follow-up examination after the second step. The mean central corneal thickness was 526 ± 6 μm (517 to 530 μm). Conclusions. The absence of complications in two-steps laser-assisted selective stromal transplantation demonstrates the safety of the technique. The improvement of visual acuity in all patients indicates the effectiveness of the procedure. The two-steps modification retains the same advantages as the one-step modification. At the same time, the two-steps technique has extended indications for surgery and provides higher functional refractive results due to the presence of only one interface and smooth anterior surface as a result of the excimer laser.