Human Fresh Corneal Lenticule Implantation Criteria in Progressive Corneal Disease Using Relex-Smile (Relex-Smile)

Stroma is a fibrous, tough, transparent and the thickest layer of the corneae. The stroma is composed of organised collagen, which maintains transparency. Keratocytes are located between the lamella collagen fibers and secrete an extracellular matrix, which includes collagen, proteoglycan, crystalline proteins to maintain corneal transparency.

Knowing the importance of stroma(90%) in function and anatomy of corneae (transparence, curvature, strength, protection) the inner eye structures from external environment, we have examined the role and function of stroma as a main factor of corneal thickness in implanting fresh corneal lenticule in progressive corneal disease. We have studied that in many clinical cases where the corneal epithelium and endothelium are healthy and functioning, the cornea can still lose it's transparency by different corneal stromal pathologies (infection ,keratoconus, inflammation ,neurodegeneration and corneal dystrophies).

The aim in our study is to describe the importance of stroma as criteria of corneal thickness at implanting human fresh corneal lenticule in progressive corneal disease. We have conclude that every biomechanical instability of corneal stroma function(abnormal increase collagen activity,decrease proteinase inhibitors,excessive premature keratocyte apoptosis) describe the role of stroma in corneal thickness.

Using VisuMax femtosecond laser we created the stromal pocket with diameter of 7.6 to 8.0 mm (1 mm larger than the optical zone of the donor lenticule) and cap thickness set to 130 μm from corneal surface and 4 mm superior incision. Hinge position flap was set at 90° angle 50° and width 4 mm, side cut angle 90°. The pocket was dissected using a blunt spatula washed with normal saline. The lenticule was held with lenticule forceps and gently inserted into the pocket through the 4 mm superior incision. Incision position changed according to the position of the highest K values We noticed during intervention that implantation of fresh lenticule depends from corneal thickness, for example if c.th.is 300-400 μm we implanted 1/2 stroma, if c.th.is 400 μm or more we implanted 1/3 stroma Example: if corneal thickness is 300 μm we implanted 150 μm (becoming 450 μm) we added more stroma due to more live keratocytes and stromal steam cells, aiming to overcome dead and non-functional keratocytes

Increase of corneal central thickness using human fresh corneal lenticule with stromal stem cells and live keratocytes

Inclusion Criteria: progressive corneal disease with thin corneal thickness corneal low transparenc low visual acuity Exclusion Criteria: active anterior segment pathology previous corneal or anterior segment surgery other infection etc.