A Fellow Eye Comparison of Aberrations, Modulation Transfer Function and Contrast Sensitivity After...
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Transcript of A Fellow Eye Comparison of Aberrations, Modulation Transfer Function and Contrast Sensitivity After...
A Fellow Eye Comparison of Aberrations, Modulation Transfer Function and Contrast
Sensitivity After AcrySof IQ and AcrySof Natural IOL Implantation.
Mayank A. Nanavaty, David J. Spalton,
James F. Boyce, John Marshall
St. Thomas’ Hospital, London
MAN: Honorarium from Alcon Laboratories.
DJS, JFB, JM: Consultant to Alcon Laboratories.
Introduction
•With advances in IOL design and cataract surgery success should be determined by improvement in optical and visual quality rather than just visual acuity.
•Optical quality of vision can be measured by point spread function (PSF) and from this, aberrations and modulation transfer function (MTF) can be derived.
•Contrast sensitivity depends both on the quality of the optical system and also relies on retinal and cortical processing.
•Thus, the quality of vision can be assessed in-vivo by evaluating modulation transfer function, aberrations and contrast sensitivity.
Aims of this study
To compare the optical and visual outcomes in-vivo of a spherical and an aspherical IOL in a fellow eye controlled, prospective, randomized
trial using modulation transfer function, aberrations and contrast sensitivity
Material and Methods
Prospective, randomized, fellow eye controlled study of patients with uncomplicated age-related bilateral cataracts.
All the surgeries performed with standardized technique by a single surgeon.
94 eyes of 47 patients received either an aspheric IOL (AcrySof IQ) or a spherical IOL (AcrySof Natural) in the first eye and the other IOL in the second eye within three weeks.
Postoperative observations• Patients followed up at 1, 3 and 6 months postoperatively
• 100% and 9% EDTRS LogMAR BCVA assessed
• Functional assessment of contrast vision (FACT) measurements done at 3 and 6 months on OPTEC 6500®
under photopic (85 cd/m2) and mesopic condition (3 cd/m2) without glare at patients natural pupil size.
• At 3 and 6 months PSF and corneal topography were performed with the iTrace Dynamic Laserefraction with Vista attachment (Tracey technologies, Houston, USA) after dilatation of pupils.
• The wavefront maps were analyzed for a pupil scan size of 5 mm and up to 6th order of Zernike coefficients.
• MTF was calculated by the software from the PSF.
Results
• Preop K readings, axial length, IOL power, p value = ns
• Corneal Q values at 1 month, p value = ns
• Postop spherical equivalent, p value = ns
• 100% and 9% LogMAR BCVA at 1,3 and 6 months, p value = ns
Higher order aberrations
Total aberrations
MTF due to HOA at 3 months
0.0000.100
0.2000.300
0.4000.500
0.6000.700
0.8000.900
1.000
5 10 15 20 25 30
Cycles/degree
MT
F AcrySof IQ
AcrySof SN
MTF due to HOA at 6 months
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
5 10 15 20 25 30
Cycles/degree
MT
F AcrySof IQ
AcrySof SN
MTF
*
3 months
6 months
*
***
*
*
*
***
*
* P value <0.05
Total MTF at 6 months
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
5 10 15 20 25 30
Cycles/degree
MT
F AcrySof IQ
AcrySof SN
**
* ** *
Total MTF at 3 months
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
5 10 15 20 25 30
Cycles/degree
MTF
AcrySof IQ
AcrySof SN
**
* ** *
Mesopic contrast
sensitivity at 3 cd/m2
Photopic contrast sensitivity at 3 months
0
20
40
60
80
100
120
140
1.5 3 6 12 18
Cycles/degree
Con
trast
Sen
sitiv
ity
AcrySof IQ
AcrySof SN
Mesopic contrast sensitivity at 3 months
0
20
40
60
80
100
120
140
1.5 3 6 12 18
Cycles/degree
Contr
ast
sensitiv
ity
AcrySof IQ
AcrySof SN
**
*
Mesopic contrast sensitivity at 6 months
0
20
40
60
80
100
120
140
1.5 3 6 12 18
Cycles/degree
Con
tras
t se
nsiti
vity
AcrySof IQ
AcrySof SN
**
*
Photopic contrast sensitivity at 6 months
0
20
40
60
80
100
120
140
1.5 3 6 12 18
Cycles/degree
Co
ntr
ast
se
nsitiv
ity
AcrySof IQ
AcrySof SN
Photopic contrast
sensitivity at 85 cd/m2
* P value <0.05
Spherical Aberration Z4(0)
Vertical Coma Z3(-1)* * *
Entire eye Z4(0) at follow up visits with 5 mm pupil
-0.100
-0.050
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
1 month 3 months 6 months
Follow up visits
RM
S AcrySof IQ
AcrySof Natural
* * *
Entire eye Z3(-1) at follow up visits
-0.500
-0.400
-0.300
-0.200
-0.100
0.000
0.100
0.200
0.300
1 month 3 months 6 months
Follow up visits
RM
S
AcrySof IQ
AcrySof Natural
* * *
* P value <0.05
Summary
• MTF is consistently better with AcrySof IQ at all frequencies.
• AcrySof IQ gives better mesopic contrast sensitivity at 3, 6 and 12 cycles/degree.
• Entire eye spherical aberration is always less with AcrySof IQ (mean RMS difference was 0.15µm, 0.2µm and 0.21µm at 1, 3 and 6 months).
• Entire eye vertical coma Z3(-1) aberration was significantly more negative with AcrySof Natural at all follow up visits.