Application of different Scheimpflug-based lens densitometry methods in phacodynamics prediction.
OBJECTIVE
To evaluate the correlations between preoperative Scheimpflug-based lens densitometry metrics and phacodynamics.


METHODS
The Lens Opacities Classification System III (LOCS III) was used to grade nuclear opalescence (NO), along with different methods of lens densitometry evaluation (absolute scale from 0% to 100%): three-dimensional (3D), linear, and region of interest (ROI) modes. Cumulative dissipated energy (CDE) and total ultrasound (US) time were recorded and correlated with the different methods of cataract grading. Significant correlations were evaluated using Pearson or Spearman correlation coefficients according to data normality.


RESULTS
A positive correlation was detected between the NO score and the average density and the maximum density derived from the 3D mode (r=0.624, P<0.001; r=0.619, P<0.001, respectively) and the ROI mode (r=0.600, P<0.001; r=0.642, P<0.001, respectively). Regarding the linear mode, only the average density parameter presented a significant relationship with the NO score (r=0.569, P<0.001). The 3D-derived average density and maximum density were positively correlated with CDE (rho =0.682, P<0.001; rho =0.683, P<0.001, respectively) and total US time (rho =0.631 and rho =0.668, respectively). There was a linear relationship between the average density and maximum density of the ROI mode and CDE (rho =0.686, P<0.001; rho =0.598, P<0.001, respectively) and total US time (rho =0.642 and rho =0.644, respectively). The average density was the only parameter derived from the linear mode that showed a significant correlation with CDE (rho =0.522, P<0.001) and total US time (rho =0.450, P<0.001).


CONCLUSIONS
Specific Scheimpflug-derived densitometric parameters of the nucleus correlated with phacoemulsification parameters. The use of the appropriate densitometry approach can predict more efficiently the phacodynamics.
Ophthalmology Department, Hospital de Braga, Braga, Portugal; Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Guimarães, Portugal; Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil.
Fernando
F
Faria-Correia
Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil; Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil.
Bernardo T
BT
Lopes
Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil; Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil.
Isaac C
IC
Ramos
Ophthalmology Department, Hospital de Braga, Braga, Portugal; Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.
Tiago
T
Monteiro
Ophthalmology Department, Hospital de Braga, Braga, Portugal.
Nuno
N
Franqueira
Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil; Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil; VisareRio, Rio de Janeiro, Brazil; Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, São Paulo, Brazil.
Renato
R
Ambrósio
cataract; densitometry; phacoemulsification; scheimpflug