Optical outcomes of complete ring implantation in cases of corneal ectasia using the femtosecond technology

Session Details

Session Title: Corneal Biomechanics

Session Date/Time: Tuesday 13/09/2016 | 16:30-18:00

Paper Time: 17:54

Venue: Auditorium C6

First Author: : A.El Aswad EGYPT

Co Author(s): :                        

Abstract Details

Purpose:

To evaluate the clinical outcomes after MyoRing implantation by means of femtosecond laser technology in eyes with corneal ectasia and to evaluate the biomechanical changes caused by the creation of the 9mm diameter pocket in the already questionable biomechanical status of the ectatic corneas.

Setting:

Retrospective, consecutive, nonrandomized, case series of 12 eyes of 11 patients with ages ranging between 17 and 50 years. 1 case of post-LASIK ectasia and 11 cases of keratoconus. / Vissum instituto oftalmologico, Alicante, Spain

Methods:

MyoRing (DIOPTEX) inserts of 280 μm of thickness and 5 mm of diameter were implanted in all cases into an intrastromal corneal pocket created by means of femtosecond technology. Visual, refractive, corneal topography and pachymetric changes were evaluated during a 6-month follow-up. Additionally, corneal biomechanical changes were evaluated by means of the Ocular Response Analyzer (Reichert).MAIN OUTCOME MEASURES: uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, keratometry, corneal asphericity, corneal higher order aberrations(HOA) ,pachymetry, corneal hysteresis (CH) and corneal resistance factor (CRF).

Results:

UDVA improved 1 week postoperative (p=0.001), which was consistent with the significant reduction in sphere (p=0.002) and cylinder (p=0.004). Corneal flattening of a mean value of 8.03 diopters was found (p=0.005). This keratometric change was correlated with the magnitude of corneal coma-like aberrations (r=0.830, p=0.003) and the CRF (r=-0.782, p=0.008). An increase in primary spherical aberration was found at 1 month (p=0.001). A significant reduction in HOA was found between the third and sixth postoperative months (p=0.027). Significant corneal thickening was observed in the central, nasal and temporal areas (p≤0.013). Regarding corneal biomechanics, no statistically significant changes were detected (p≥0.176).

Conclusions:

It's a common belief that ectatic corneas have altered biomechanics, The whole 9 mm in diameter intracorneal pocket used to implant the complete ring when made by femtosecond doesn't jeopardize the corneal biomechanic . Complete ring implantation by femtosecond technology causes flattening of the ectatic cornea by mean value of 8 diopters which markedly improves the optical outcome of the procedure.

Financial Disclosure:

NONE