Adjustable intracorneal ring in a lamellar pocket for keratoconus.

PURPOSE No theory or method currently exists to preoperatively predict the optimal position of an intracorneal implant for the treatment of keratoconus, or a surgical system or technique to adjust and optimize the position of the implant after its implantation. A surgical technique for adjusting the position of the implant inside the cornea is presented, and by adjusting the position of the implant after its insertion into a corneal pocket, the surgical results in keratoconus treatment may be improved. METHODS After the formation of a closed pocket of 9 mm in diameter and 300 mum in depth within the corneal stroma, a flexible full-ring implant is inserted into the corneal pocket via a narrow incision tunnel. After insertion and evaluation of the clinical data, the implant position can be adjusted inside the pocket to achieve an optimal treatment result. RESULTS The procedure is quick and easy to perform. An adjustment of the implant position of only 0.5 mm towards the apex of the cone may dramatically improve the surgical result. CONCLUSIONS The presented technique enables the surgeon to access all three degrees of freedom possible in theory, which are associated with intracorneal implants in a corneal stroma, including implant diameter, implant thickness, and implant position. This is of particular importance for the treatment of irregularly shaped corneas such as in keratoconus.