Transcript Effect of intraocular lens material on optical quality of

Mayank A. Nanavaty,
DO, MRCOphth, MRCS(Ed)
David J. Spalton, FRCP, FRCS, FRCOphth
James F. Boyce, PhD
Thomas J. T. P. Van den berg, PhD
St. Thomas’ Hospital,
London
None of the authors have any financial or proprietary interest
• Optical quality of vision is dependent on aberrations,
PSF, MTF and ocular scatter apart from visual acuity.
• There is paucity of information on influence of IOL
material on optical quality
• One published study objectively quantifying the
relationship between IOL material and ocular scatter
Tanaka et al.
Limitation of Scheimpflug videophotography system in quantifying posterior capsule
opacification after intraocular lens implantation.
Am J Ophthalmol 2004 Apr;137(4):732-5.
Aim
To analyze the effect of IOL material on
optical quality in eyes
with clear posterior capsules using the
asymmetric double pass technique with
Optical Quality Analysis System (OQAS II)
Methods
• Retrospective, non-randomized, observational study
• Patients with clear posterior capsule were recruited
from the follow up of two different ongoing
prospective, randomized fellow eye controlled
studies comparing
• Hydrophilic - AcriSmart 36A & Akreos MI60
• Hydrophobic - AcrySof IQ & AcrySof Natural
• Single surgeon with standardized surgical technique
Eyes with clear capsule in central 4mm zone on
POCOman analysis of digital retro-illumination images
were recruited
Hydrophilic
IOLs
AcriSmart 36A
AcrySof IQ
Hydrophobic
IOLs
Akreos MI60
AcrySof Natural
Methods
• Data of:
•100% & 9% LogMAR BCVA
• Entire eye aberrations at 4mm scan size
• 50% & 10% PSF, MTF and Strehl ratio after
correcting LOA
was extracted for these eyes with clear posterior
capsules
• Two 20D IOLs of each IOL type was sent for in-vitro
analysis of light scatter
• 160 eyes of 80 patients were screened
• 71 eyes of 46 patients had clear capsules
• 58 were white Caucasians, 9 Afro-Caribbean, 2 Indians, 2 Mongolians
Postoperative duration
(days)
IOL power (diopters)
Postoperative Spherical
Equivalent (Diopters)
Hydrophilic IOLs
[mean ± standard
deviation (95%
confidence interval)]
(n=28)
Hydrophobic IOLs
[mean ± standard
deviation (95%
confidence interval)]
(n=43)
p values*
127.7 ± 41.2
(122.3, 133.0)
342.6 ± 65.6
(335.7, 349.4)
0.000¥
19.75 ± 5.20
(19.07, 20.43)
-0.19 ± 0.60
(-0.27, -0.11)
21.13 ± 4.02
(20.71, 21.55)
-0.10 ± 0.59
(-0.16, -0.04)
0.240
0.534
*Unpaired two tailed t test, ¥ Statistically significant, p < 0.05, BCVA = Best corrected visual acuity,
• No significant difference in aberrations at 4 mm scan size except
Zernicke’s polynomial 4 (defocus)
p = 0.000
0.6
LogMAR
0.4
p = 0.127
0.2
0.0
100% LogMAR
9% LogMAR
-0.2
Hydrophilic Acrylic
Hydrophobic Acrylic
PSF measurements
Optical Quality analysis system (OQAS II)
p = 0.005
PSF Value (arc min)
50
40
30
p = 0.008
20
10
0
50% PSF
Measurements done after
correcting sphere and cylinder
10% PSF
Hydrophilic Acrylic
Hydrophobic Acrylic
There was no significant difference in MTF and Strehl ratio between to the two
IOL groups
2
cataract (10x)
log straylight parameter
1.5
good 77 old eye (3x)
1
hydrophilic
young eye (1x)
hydrophobic
0.5
young eyes
good 77y old
cataract (10x)
0
-0.5
-1
-25
-20
-15
-10
-5
0
5
10
15
20
25
scatter angle (degrees)
Although in-vitro scatter levels are low with acrylic IOLs, hydrophilic
acrylic IOLs have more scatter than hydrophobic acrylic IOLs
• IOL material has no effect on 100% BCVA, entire eye
aberrations, MTF and Strehl ratio
• Hydrophilic Acrylic IOLs have reduced 9% LogMAR
BCVA
• Ocular scatter is more with hydrophilic Acrylic IOLs
• This may be because of increased opalescence of the
hydrophilic acrylic material due to more water content