Transcript 318: Analysis of Ocular Wavefront Aberrations in Post Penetrating

Analysis of Ocular Wavefront Aberrations
in Post Penetrating Keratoplasty Eyes with
Two Different Hartmann-Shack
Aberrometers
Adriana S. Forseto1, MD; Telma Pereira2, MD; Vera
Mascaro2, MD; Lucila Pinto1, MD; Walton Nosé1,2, MD
1Eye
Clinic Day Hospital
2Federal University of São Paulo - UNIFESP
São Paulo - Brazil
The authors have no financial interest in the subject matter of this poster
Introduction
 Penetrating keratoplasty (PKP) is still widely performed as a
treatment option for the correction of advanced keratoconus.
However, visual rehabilitation is so far influenced by the presence
of different degrees of refractive errors.
 Several surgical refractive treatments have already been proposed.
Unfortunately, the amount of total higher-order aberrations (HOA)
present in these eyes is faraway that observed in non operated
eyes. This may influence the visual quality experienced by these
patients.
 Many wavefront sensors have more difficulty of measuring the
ocular aberrations on eyes with highly irregular corneas.
Inaccuracies in wavefront measurements may compromise clinical
testing and the refractive correction procedures.
 Another concern is the presence of possible discrepancies between
the wavefront-derived refractions and the clinical measurements,
since many customized ablation platforms use these data to treat
the refractive error.
Purpose
To analyze ocular order aberrations derived
from Ladarwave (Alcon) and Zywave
(Bausch & Lomb) devices in eyes after
penetrating keratoplasty (PKP) for
keratoconus (KC) and to compare the
clinical refraction with the lower order
aberrations obtained from these two
aberrometers
Methods
 Thirty eyes were evaluated with 2 wavefront
(WF) sensors:
 Ladarwave and Zywave
 Inclusion criteria
 Minimum age: 18 yo
 History of PKP for KC
 Clear corneal graft
 Previous removal of all
keratoplasties sutures
 Exclusion criteria
 Other ocular
pathology than KC
 Other previous
surgery than PKP
 Contact lens wear
Methods
 The WF refractions were evaluated for 3.50mm
pupil and compared with the clinical measurements
(manifest and cycloplegic), after conversion to
power vectors coordinates: spherical equivalent (M
or Sph Eq), J0 and J45 (astigmatism)(1)
 The WF aberrations (up to the 4th order) were
compared between the 2 devices (6.00mm pupil size)
 Parametric testing was used with a significant level
of p < 0.05
(1)Thibos
LN, Wheeler W, Horner DG. Power vectors: an application of Fourier analysis to the
description and statistical analysis of refractive error. Optom Vis Sci 1997;74:367-375.
Results
 The mean time between PKP and WF examinations was:
 5.95±4.37 years (range, 1 to 15 years)
 The Zywave aberrometer was unable to capture the
images in 3 eyes and the Ladarwave in one of them
Centroids view and processed image in post PKP eye
Note the irregularities at the periphery
Results
Correlation between the manifest and the Ladarwave
and the Zywave derived refraction
Manifest refraction
Ladarwave
Zywave
Sph Eq
r = 0.97
p < 0.001 *
r = 0.97
p < 0.001 *
Vector J0
r = 0.97
p < 0.001 *
r = 0.97
p < 0.001 *
Vector J45
r = 0.92
p < 0.001 *
r = 0.94
p < 0.001 *
Both wavefront devices derived refractions were highly correlated to clinical manifest
refraction
Results
Correlation between the cycloplegic and the Ladarwave
and the Zywave derived refraction
Cycloplegic
refraction
Ladarwave
Zywave
Sph Eq
r = 0.99
p < 0.001 *
r = 0.99
p < 0.001 *
Vector J0
r = 0.97
p < 0.001 *
r = 0.95
p < 0.001 *
Vector J45
r = 0.91
p < 0.001 *
r = 0.94
p < 0.001 *
Both wavefront devices derived refractions were highly correlated to clinical
cycloplegic refraction
Results
Analysis of variance with repeated measurements of the
clinical and the wavefront sensors-derived refractions
Variables
Mean Sph Eq (SD)
Range
Mean J0 (SD)
Range
Mean J45 (SD)
Range
Clinical Refraction
WF sensor derived-refraction
Manifest
Cycloplegic
Ladarwave
Zywave
-3.65 (3.75)
-2.98 (3.99)
-3.30 (4.20)
-2.80 (4.18)
-15.00 to 1.75
-15.00 to 3.38
-16.09 to 3.61
-15.49 to 4.02
0.34 (1.62)
0.23 (1.77)
0.31 (2.01)
0.11 (2.13)
-2.13 to 3.20
-2.11 to 3.45
-2.99 to 3.78
-3.03 to 3.78
-0.29 (1.41)
-0.25 (1.67)
-0.29 (1.67)
-0.27 (1.54)
-2.17 to 2.75
-2.35 to 2.57
-4.42 to 2.84
-3.09 to 2.49
Statistically significant differences (p < 0.05) were found between:
•LADARWave Sph Eq and Zywave Sph Eq
•LADARWave J0 and Zywave J0
• Zywave SphEq and the manifest Sph Eq
•LADARWave Sph Eq and the cycloplegic Sph Eq
Results
Mean values of total HOA, 3rd and 4th HOA
1,8
1.79
1,6
1.74
Zywave
1.21 1.22
1,4
RMS (micra)
Ladarwave
1,2
0.84 0.78
1
0,8
(6.00mm pupil)
0.59 0.6
0,6
0.48 0.43
0.3 0.25
0,4
0,2
0
HOA
coma
trefoil
spherical
Aberrations
sec
quadrifoil
astigmatism
•No statistically significant discrepancies in higher-order aberrations (HOA)
measurements between the two Hartmann-Shack devices were observed.
•Trefoil aberrations were dominant when compared to coma or spherical aberrations in
post-PKP eyes.
Conclusions
Eyes with PK have a great amount of
ocular aberrations
The correction of these aberrations
may be limited by the discrepancies
among the wavefront refractions and
the clinical measurements, since these
customized ablation platforms use their
own data to treat the refractive error
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