Early Ocular Biomechanical Changes After Femtosecond-Laser-Assisted Refractive Cataract Surgery

Valbon, Bruno

Early Ocular Biomechanical Changes After Femtosecond-Laser-Assisted Refractive Cataract Surgery

Friday, April 25, 2014

KIOSKS (Boston Convention and Exhibition Center)

Bruno F. Valbon, MD, University of São Paulo, Niterói, Brazil

Marcella Salomão, MD, Barra Vision Center, Rio de Janeiro, Brazil

Ana Laura C. Canedo, MD, VisareRio, Rio de Janeiro, Brazil

Isaac C. Ramos, MD, Hospital de Olhos Santa Luzia, Maceió-AL, Brazil

Allan Luz, MD, Hospital de Olhos de Sergipe, Aracaju, Brazil

Bernardo T. Lopes, MD, Rio de Janeiro Corneal Tomography and Biomechanical Study Group, Rio de Janeiro, Brazil

Cynthia J. Roberts, PhD, The Ohio State University, Columbus, Ohio, USA

Luca Gualdi, MD, D.O.M.A., Rome, Italy

Renato Ambrósio Jr., MD, PhD, Inst. Olhos R. Ambrósio, Rio de Janeiro, Brazil

Milton R. Alves, PhD, University of Sao Paulo, Sao Paulo, Brazil

Narrative Responses:

Purpose
To describe ocular biomechanical changes in the early post-operative period of patients who underwent femtosecond laser (FL)-assisted cataract surgery and to evaluate the influences of the differences on intraocular pressure (IOP) measurements and on central corneal thickness (CCT) on them changes that occurred on corneal deformation response.

Methods
This retrospective study comprised 76 eyes of 62 consecutive patients who had FL-assisted cataract surgery. Dynamic ultra-high speed Scheimpflug imaging and Pentacam (Corvis ST; Oculus, Wetzlar, Germany) were performed prior to surgery and at 1 day postoperatively. The differences of the preoperative and first postoperative day on IOP, CCT and on corneal deformation parameters were assessed using Student T Test or Wilcoxon signed-rank accordingly to the type of distribution (Kolmogorov Smirnov). The percentual change of IOP (delta IOP) and CCT (delta CCT) were correlated to all parameters from Corvis ST.

Results
There were statistically significant differences on CCT, IOP and all parameters from Corvis ST, excluding highest concavity-time, second applanation length and maximal deflection amplitude (≤ 0.05). Deformation amplitude and parameters of corneal velocities as A1 time were lower at 1 day compared preoperatively (≤ .0001). There was a significant increase on CCT and IOP. There were more significant correlations, with higher correlation coefficients between the difference on corneal deformation parameters and the delta IOP than with delta CCT. IOP was negatively associated with deformation parameters such as maximal deformation and deflection amplitude in preoperatively and 1 day postoperatively (≤ .0001).

Conclusion
There is mild edema and mild ocular hypertension in the first day after FS-assisted cataract surgery. The influence of IOP had higher correlations with the changes on ocular biomechanics than CCT.