Abstract
PURPOSE
To evaluate changes in keratoconic corneas implanted with intracorneal ring segments (ICRS) that have been explanted due to late extrusion of the segment after >2 years.
SETTING
Vissum Miranza, Alicante, Spain; OftalmoSalud, Lima, Peru; Minya University Hospital, Egypt.
METHODS
Retrospective, multicenter, series of cases of 23 keratoconic corneas that have been implanted for > 2 years and have been explanted due to natural extrusion of the segment. Clinical measures of visual, refractive, topographic, pachymetric and aberrometric data were analyzed. To perform exploratory factor analysis, the Kaiser-Meyer-Olkin (KMO) test was used to evaluate sampling adequacy. Factor analysis with VARIMAX rotation was used to determine the main factors of the inventory.
RESULTS
Mean time interval 5 years. Topographic findings were reversed nearly to the baseline level after segment explantation (p>0.05). Significant worsened in refractive cylinder was found pre-ICRS extrusion (p<0.05). KMO revealed a suitability of 0.528 in the preimplantation matrix (p<.001), 0.534 in the postimplantation matrix (p<.001), 0.549 in the preexplantation matrix (p=.009). Main factor obtained in the preimplantation moment included keratoconus grade, keratometric readings and visual acuities. After ICRS implantation, the most strength components were the refractive cylinder, CDVA and UDVA. Corneal aberrations were the main factors in the preexplantation analysis.
CONCLUSIONS
ICRS can be safely extracted, with a reversal of the corneal topographic data to the preoperative level. We showed a significant astigmatic change in patients implanted with ICRS before late extrusion of the segment, suggesting the role of this parameter as a prognostic factor of extrusion.
Collapse