Resistance to Glare Disability Provided by

Blue Light–Filtering IOLs:

Contralateral-Controlled Study

W. Andrew Maxwell, MD, PhDCalifornia Eye Institute; Fresno, CA

and

Billy R. Hammond, Jr, PhDVision Sciences Laboratory, University of Georgia; Athens, GA

Disclosures:This study was funded by Alcon Research, Ltd, which also assisted with the preparation

of these slides.Dr. Maxwell is a consultant to Alcon.

2

Introduction

Background: Glare light, such as the light from oncoming headlights,can reduce visual performance.

Purpose: This study was designed to compare glare disability…

…in eyes with intraocular lenses (IOLs) that filtered short-wave blue light…

Schematic colors and shapes are not anatomically or scientifically accurate; they are for purposes of explanation only.

…contralateral eyes with IOLs that did not filter

visible blue light.

…versus…

Eligible subjects were at least 12 months post-implantation of – a control IOL (model SA60AT; Alcon) and– a contralateral IOL that filtered blue light (spherical SN60AT or aspheric SN60WF; Alcon)

Test apparatus was a 2-channel Maxwellian-view optical system to

produce a glare light and a target light on the retina of the subject:

Methods: Subjects and Apparatus

3

Channel 2: Visual Target

Channel 1: Glare light

aperture

neutral density filter holder wedge (circular attenuating filter, to change glare intensity)

aperture

neutral density filter holder

mir

ror

beam splitter

eye

pupil viewer

beam splitter

Produced by a xenon lamp, to mimic xenon headlights or to approximate daytime

sunlight spectrum

(Produced by a halogen lamp)

4

Methods: A Subject’s View of the Test

1. Subject sawA. a 3.1°-diameter halogen-light disk as the targetB. an annulus from the xenon channel with

• a shape that was 20° inner and 22° outer diameter • an intensity that was too low to obscure the target

Technician increased glare intensity

2. Subject sawA. the same central 3.1°-diameter disk, butB. the brightness (ie, the glare) of the annulus was

beginning to move toward obscuring the central target

AB

AB

Schematics are not exact representations; they are for purposes of explanation only.

Technician increased glare intensity

3. Subject sawA. no central 3.1°-diameter disk, becauseB. the glare from the annulus had obscured the central

target. The intensity of the annulus of light at that point was defined as the glare disability value.

AB

5

Methods: Replicates and Analyses

Measurements– Masking: The technician who took the measurements was

masked to the IOL type in each eye.– Replicates: 5 measures were taken per eye, unless a

subject’s values had >5% variability, in which case up to4 additional trials were conducted. If extra trials were conducted, all trials were averaged into the mean result.

Analyses– Comparisons between IOL groups were performed using

paired t-tests.– The mean values are presented as log energy values

(µW/cm2).

6

Results: Demographics

At 5 clinical sites, a total of 52 subjects were enrolled.– 28 were women (54% of cohort) and 24 were men (46% of cohort).

– Mean age = 76 ± 9 years

– All subjects had a control SA60AT lens in 1 eye, and

▪ 50% of subjects (26 of 52) had a contralateral model SN60AT lens(spherical IOL with the blue-filtering chromophore), and

▪ 50% of subjects (26 of 52) had a contralateral model SN60WF lens(aspheric IOL with the blue-filtering chromophore).

– The average duration of pseudophakia before entering the study was statistically similar between IOL groups, at

▪ 5.2 ± 1.3 years for the eyes with blue-filtering IOLs, and

▪ 5.6 ± 1.3 years for the eyes with control SA60AT IOLs, with

▪ average duration between contralateral IOL implantations of 0.4 ± 1.1 years.

7

Results: Monocular Distance Visual Acuity

Blue-filtering IOL group,n = 52

Control SA60AT group,n = 52

Uncorrected , logMAR

Mean ± standard deviation

Range (worst, best)

0.2 ± 0.2

(0.9, -0.1)

0.2 ± 0.2

(0.7, -0.1)

Corrected , logMAR

Mean ± standard deviation

Range (worst, best)

0.03 ± 0.09

(0.3, -0.1)

0.02 ± 0.09

(0.4, -0.2)

(similar between groups)

8

Results: Glare Disability

For the overall population of 52 subjects at 5 clinical sites, significantly more glare light (P = 0.04) could be withstood by eyes with blue-filtering IOLs (1.97 ± 0.44 log µW/cm2) than by eyes with non-filtering control IOLs (1.88 ± 0.43 log µW/cm2)before losing sight of the target.

For the subpopulation of13 subjects at the Fresno site,†

significantly more glare light(P < 0.05) could be withstood byeyes with blue-filtering IOLs thaneyes with non-filtering control IOLs before losing sight of the target

†Site of Fogg, Maxwell, Lanier & Remington Eye Care

9

Discussion & Conclusions

Key finding: Compared with eyes with control IOLs, the eyes with blue-filtering IOLs had a higher mean threshold (higher mean resistance) to glare disability.

Proposed mechanism: The light entering the eye from the glare source was scattered toward the retina by the intraocular media, causing a veiling luminance over the visual target. Blue-filtering IOLs prevented some of the glare scatter.

Real-world applications: Analogous situations could occur under bright midday sunlight or when a driver is looking into oncoming headlights. By filtering such glare sources with a blue-filtering IOL, the visibility of a target within an individual’s sight line would be improved, and better edge detection could be provided, as was demonstrated by the model in this study.

Read more at: Hammond BR, Renzi LM, Sachak S, Brint SF. Contralateral comparison of blue-filtering and non-blue-filtering intraocular lenses: glare disability, heterochromatic

contrast, and photostress recovery. Clin Ophthalmol. 2010;4:1465-1473 Gray R, Perkins SA, Suryakumar R, Neuman B, Maxwell WA. Reduced effect of glare disability on driving performance in patients with blue light–filtering intraocular

lenses  J Cataract Refract Surg 2011;37:38-44