Posters

Tomographic and biomechanical corneal analysis in ring segment implantation for keratoconus

Poster Details

First Author: P.Baptista PORTUGAL

Co Author(s):    T. Mazzeo   R. Ambrósio Jr                 

Abstract Details

Purpose:

The aim of this study is to correlate corneal tomographic and biomechanical aspects with both visual and refractive outcomes of ICRS surgery.

Setting:

Instituto de Olhos Renato Ambrósio and Rio de Janeiro Corneal Tomography and Biomechanics Study Group.

Methods:

Observational retrospective study, in which 26 eyes of 20 patients (15 males and 5 females) with a mean age of 27,5 years (15 to 41), with mild to moderate keratoconus (KC), were analyzed before and 6-months after intracorneal ring segments (ICRS) implantation surgery. The pre and postoperative comparative analysis included uncorrected and corrected distance visual acuities (UDVA and CDVA), refractive error, tomographic and biomechanical evaluation. The study was done using Pentacam HR and Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany ®) for tomographic and biomechanical assessment, respectively. MedCalc Statistical Software (version 16.8.4) was used for statistical analysis.

Results:

Considering all cases, there was a significant improvement in cylindrical refractive error from a mean value of -4.625 to -1.250 6 months after surgery (P<0,05). UDVA and CDVA converted to logarithm of minimal angle resolution (LogMAR) were also significantly better after ICRS implantation (p<0,05). The mean preoperative UDVA and CVDA were 0.602 and 0.349 LogMAR respectively, whereas 6-months after ring implantation were 0.301 and 0.096 LogMAR respectively. We found a correlation between Improvement of visual acuity and pachimetry (IC 95% -0.693 to -0.0369)

Conclusions:

ICRS are safe and useful for corneal modeling in keratoconus, however, biomechanical changes not yet fully understood, can be responsible for the limitation of the ring segments effect in some cases, leading to optical and refractive variability outcomes. Biomechanical parameters can assist to predict postoperative visual outcomes in the short and long term in these patients, however, more studies with bigger samples and multivariate analysis are needed to elucidate this hypothesis.

Financial Disclosure:

None