Femtosecond laser-assisted implantation of complete versus incomplete rings for keratoconus treatment

Abstract

PurposeTo compare complete versus incomplete ring implantation for keratoconus correction.MethodsWe investigated 25 eyes of keratoconic patients, of which 15 had femtosecond-assisted MyoRing corneal implantation (Group 1) and 10 had femtosecond-assisted Keraring segments (Group 2). Uncorrected distance visual acuity (UCVA), best corrected distance visual acuity (BCVA), mean K (Km), sphere, topographic cylinder, and corneal asphericity value (Q-value) were measured in all eyes preoperatively and at 4 weeks postoperatively (1 month).ResultsIn Group 1, the Km change was −6.15±2.16 D, with a mean change in sphere of 4.45±2.18 D and a mean change in refractive cylinder of 2.32±3 D. UCVA change was −0.57±0.273 logarithm of the minimum angle of resolution (LogMAR), BCVA change was −0.2±0.27 (LogMAR), and the Q-value change was 0.43±2.6. In Group 2, the Km change was −3.15±1.68 D, UCVA change was −0.48±0.37 (LogMAR), BCVA change was −0.09±0.15 (LogMAR), and the Q-value change was 0.5±0.21. Changes in the means did not significantly differ between groups, except for the Km change, which was significantly greater in Group 1 than in Group 2 (P=0.05).ConclusionBoth complete ring and ring segment implantation are effective for improving corneal and visual parameters in keratoconus. Complete ring implantation may have a greater flattening effect on the anterior corneal surface.

Characterization of the effect of intracorneal ring segment in corneal ectasia after laser refractive surgery

“…Other studies evaluating the outcomes of KeraRing implantation but in keratoconus patients have also shown a positive change of anterior corneal asphericity. 23,24 This change to a less prolate shape indicates the ability of the ring segments to reduce the corneal protrusion generated by the ectasia. Likewise, in agreement with previous studies conducted on keratoconus patients, [25][26][27] a significant change in the steepest posterior corneal curvature was induced with the implantation of the ICRS.…”

Comparative analysis of two different types of intracorneal implants in keratoconus: A corneal tomographic study

“…Mean decreased keratometry ratio in MyoRing to KeraRing groups reported by Al-Tuwairqi et al was 1.43 D (6.51/4.55) and the value reported by Hosny et al was 1.95 D, while in the present study this ratio was 3.11 and 2.43 D for the mean and maximum (Kmax) front surface keratometry, respectively. 25,26 There are studies, however, which reported no significant changes in mean and maximum keratometry readings between ICRS and CICR. 27 However, they mentioned more effect of MyoRing and 320-degree ring compared to two segments rings.…”

Changes in Corneal Asphericity after MyoRing Implantation in Moderate and Severe Keratoconus

“…In another study by Hosny et al, the corneal asphericity was evaluated only in a MyoRing with a diameter of 6 mm. [29] The mean change in the corneal asphericity was 0.43 ± 2.6 after the MyoRing implantation. The less favorable outcome of this study compared to the present study could be due to the difference in the duration of follow-up after the surgery.…”