Correlation between Preoperative cataract grading by
Scheimpflug imaging and phaco time and power US
in phacoemulsification.
Bruno Valbon; Ana Canedo; Leonardo Pimentel; Isaac Ramos; Ricardo Louzada; Renato Ambrósio Jr.
* Dr. Ambrosio is a consultant to Oculus and in the speaker bureau for Reichert, Alcon and Allergan
Purpose : To analyze the correlation between patient
nuclear score (PNS) by Scheimplufg imaging and
phaco time and power US in patients who had
uneventful clear cornea phacoemulsification
Valbon B; Canedo A; Pimentel L; Ramos Isaac, Louzada R. Ambrosio Jr R
INTRODUCTION

The current standard for grading cataracts is the Lens Opacification Classification System III (LOCS III).

This system is, however, potentially subjective and the results are open to interpretation. An objective and
reproducible method of cataract evaluation is not yet available.

Furthermore, there is no universal means by which to correlate the objective cataract evaluation with the amount
of energy needed to remove a cataract during phacoemulsification.

The efficiency of ultrasound (US) energy use in phacoemulsification systems is critical.

Lower levels of US power can limit endothelial cell damage; therefore, it makes sense to plan phaco surgery
with the lowest levels of US power needed based on cataract density.

Is common for surgeons to alter phaco settings intraoperatively according to the den- sity of the cataract.

It would be more efficient to set phaco variables preoperatively based on objective and reproducible cataract
density results.
Valbon B; Canedo A; Pimentel L; Ramos Isaac, Louzada R. Ambrosio Jr R
METHODS
 Patients scheduled to have cataract surgery by the same surgeon (RA) had similar preoperative
evaluations, including Pentacam Scheimpflug assessment using the PNS.
 Patients were excluded if preoperative examinations indicated a need for complex cataract
surgery that could lead to complications.
 22 eyes from 22 patients who had uneventful clear cornea phacoemulsification and foldable IOL
implantation were included.
 Phaco time and power US were performed after surgery each patient.
 The Test Kolmorogov-Smirnov was used to evaluate normal distribuition.
 The correlations were evaluated with Pearson rank correlation. A P value lower than 0,05 was
considered statistically significant.
 PNS x Phaco Time and PNS x US power were correlations realized.
Valbon B; Canedo A; Pimentel L; Ramos Isaac, Louzada R. Ambrosio Jr R
METHODS
(PNS – pentacam nucleus staging)
Valbon B; Canedo A; Pimentel L; Ramos Isaac, Louzada R. Ambrosio Jr R
METHODS
(PNS – pentacam nucleus staging)
PNS 1
X
LOCS III
PNS 3
Valbon B; Canedo A; Pimentel L; Ramos Isaac, Louzada R. Ambrosio Jr R
Results :
 22 eyes of 22 patients were studied.
 Correlation between PNS x Phaco Time was p < 0,0050 and RP (Rank
- Pearson) 0,5757 (Graphic 1).
 Correlation between PNS x Power US was p < 0,0029 e RP( Rank Pearson) de 0,6034 (Graphic 2).
Valbon B; Canedo A; Pimentel L; Ramos Isaac, Louzada R. Ambrosio Jr R
DISCUSSION
 The ability to objectively and reproducibly assess pre-operative characteristics of the nuclear component
of a cataract to determine its grade would have value in preoperative surgical planning.

The most widely used cataract grading system, the LOCS III, is open to interpretation because
of its subjective nature; thus, surgeons have no analytical tool to link cataract grade and surgical
settings.

In this study, a Scheimplug imaging system was used to determine objective cataract grades, with the
phaco parameters adjusted preoperatively and to realize correlations between phaco time, power US and
PNS.
 This present study found a statistically significant between PNS, phaco time and power US.
 In conclusion, customizing phaco parameters based on an objective cataract grading may be a means to
improve phaco efficiency.
Valbon B; Canedo A; Pimentel L; Ramos Isaac, Louzada R. Ambrosio Jr R
Correlation between Preoperative cataract grading by Scheimpflug imaging and phaco time and power US in phacoemulsification
Bruno Valbon; Ana Canedo; Leonardo Pimentel; Isaac Ramos; Ricardo Louzada; Renato Ambrósio Jr.
valbonbruno@ig.com.br
Thank you !!
Valbon B; Canedo A; Pimentel L; Ramos Isaac, Louzada R. Ambrosio Jr R