Long-term clinical functional results after intrastromal keratoplasty using femtosecond laser IntraLase FS in patients with keratoconus

Purpose

Analysis of long-term clinical, morphofunctional and biomechanic changes of cornea after intrastromal keratoplasty with IntraLase FS femtosecond laser use in patients with keratoconus.


Material and methods

Clinical investigations were based on the results of 105 surgeries of 97 patients aged 14-42 years. The follow-up was from 3 months to 3 years. Patients were divided into two groups: first — 53 patients or 54 eyes (51%) with keratoconus degree I-II, the second group — 44 patients or 51 eyes (49%) with keratoconus degree III (according to M.Amsler classification, 1961). Standard and special examinations of all patients were made to assess the results. Intrastromal keratoplasty was performed with IntraLase FS 60 kHz femtosecond laser.


Results

Corrected and uncorrected visual acuity increased in all cases. First group had patients with a better functional result. Corneal statistic indices in patients with keratoconus exceeded the norm, but were stable after segments’ implantation. Such biomechanic indices as corneal hysteresis and corenal resistance factor increased. Aberrometric profile improved (it is an evidence of qualitative increase of visual acuity). After intrastromal keratoplasty elevation height at corneal surface and interface decreased on elevation maps measured with “Pentacam” scanning projection corneotopograph. Confocal microscopy revealed morphologic corneal changes typical for keratoconus, these changes are the reason of optic inhomogeneity. Stability of the results was noted during the entire follow-up.

Conclusions

Intrastromal keratoplasty with corneal segments’ implantation is an effective method of optic disturbances’ correction in case of keratoconus.

Femtosecond laser use for tunnel forming makes this surgery a safe and minimally invasive procedure.

Automated surgery rendering had a more unified character that is why the quantity of intra- and postoperative complications decreased.

Implantation of intrastromal segments in patients with keratoconus induced a complex of biomechanic changes leading to corneal viscous elastic properties’ increase.