The role of penetrating keratoplasty in the era of selective lamellar keratoplasty

[Intracorneal selective stromal transplantation]

Deep anterior lamellar keratoplasty or penetrating keratoplasty are currently considered the optimal methods of surgical treatment of stromal dystrophies and corneal degeneration. Despite certain advantages and benefits of these methods, they also have significant limitations: involvement of superficial corneal layers in the surgery, need for suturing, development of post-keratoplasty astigmatism etc.

PURPOSE

This study aimed to test and describe the new method of closed sutureless keratoplasty (intracorneal selective stromal transplantation), which was indicated in isolated dystrophic and degenerative pathology of the stroma.

MATERIAL AND METHODS

Intracorneal selective stromal transplantation was performed in a 62-year-old patient with stromal degeneration and intact corneal layers between the altered stroma and the Descemet's membrane posteriorly, and the Bowman's layer anteriorly. The patient also had immature senile cataract. Corneal stroma was removed and replaced with a graft in the optical center of the lens, while the endothelium, the Descemet's membrane and the Bowman's layer remained intact.

RESULTS

The proposed technique of intracorneal selective stromal transplantation makes it possible to replace only the pathologically altered stroma through closed surgical approach, without affecting the anterior and posterior surfaces of the cornea. Best-corrected visual acuity has increased in the patient from 0.01 to 0.6, while mean endothelial cell density has not changed in the course of 24-months follow-up.

CONCLUSION

The proposed keratoplasty method can be used in patients with dystrophy or degeneration of the corneal stroma and preserved endothelial cells, intact Descemet's membrane and Bowman layer. Since the superficial corneal layers are not involved during the surgery, intracorneal selective stromal transplantation combined the advantages of both deep anterior lamellar keratoplasty and endothelial keratoplasty. The biologically favorable result in this first clinical case allows a preliminary conclusion on the technical possibility and functional effectiveness of the proposed method, but further long-term observation and more clinical cases are required.

Treatment options for advanced keratoconus: A review

Traditionally, the mainstay of treatment for advanced keratoconus (KC) has been either penetrating or deep anterior lamellar keratoplasty (PK or DALK, respectively). The success of both operations, however, has been somewhat tempered by potential difficulties and complications, both intraoperatively and postoperatively. These include suture and wound-healing problems, progression of disease in the recipient rim, allograft reaction, and persistent irregular astigmatism. Taken together, these have been the inspiration for an ongoing search for less troublesome therapeutic alternatives. These include ultraviolet crosslinking and intracorneal ring segments, both of which were originally constrained in their indication exclusively to eyes with mild to moderate disease. More recently, Bowman layer transplantation has been introduced for reversing corneal ectasia in eyes with advanced KC, re-enabling comfortable contact lens wear and permitting PK and DALK to be postponed or avoided entirely. We offer a summary of the current and emerging treatment options for advanced KC, aiming to provide the corneal specialist useful information in selecting the optimal therapy for individual patients.