Attenuating Photostress and Glare Disability in Pseudophakic Patients through the Addition of a Short-Wave Absorbing Filter.

Billy R Hammond

doi:10.1155/2015/607635

Abstract

To evaluate the effects of filtering short wavelength light on visual performance under intense light conditions among pseudophakic patients previously implanted with a clear intraocular lens (IOL). This was a patient-masked, randomized crossover study conducted at 6 clinical sites in the United States between September 2013 and January 2014. One hundred fifty-four bilaterally pseudophakic patients were recruited. Photostress recovery time and glare disability thresholds were measured with clip-on blue-light-filtering and placebo (clear; no blue-light filtration) glasses worn over patients' habitual correction. Photostress recovery time was quantified as the time necessary to regain sight of a grating target after intense light exposure. Glare disability threshold was assessed as the intensity of a white-light annulus necessary to obscure a central target. The order of filter used and test eye were randomized across patients. Photostress recovery time and glare disability thresholds were significantly improved (both P < 0.0001) when patients used blue-light-filtering glasses compared with clear, nonfiltering glasses. Compared with a nonfiltering placebo, adding a clip-on blue-absorbing filter to the glasses of pseudophakic patients implanted with clear IOLs significantly increased their ability to cope with glare and to recover normal viewing after an intensive photostress. This result implies that IOL designs with blue-light-filtering characteristics may be beneficial under intense light conditions.

Highlights

The transmission of light energy drastically increases following cataract extraction in the aphakic or pseudophakic eye
Without natural blue-lightblocking mechanisms, the blue light that reaches the retina is sufficiently energetic to initiate oxidative damage, and the retina/retina pigment epithelium complex contains high amounts of photosensitizers with an action spectrum that matches the waveband of approximately 400 to 500 nm. Another ramification of filtering light in the visible spectrum is that it alters the incoming stimulus and changes visual function, as has been demonstrated by studies using psychophysical methods to measure the optical density of naturally occurring intraocular BLFs like the anterior lens [6] or macular pigment [7]
One patient was invalidated because they violated inclusion/exclusion criteria

Summary

Introduction

The transmission of light energy drastically increases following cataract extraction in the aphakic or pseudophakic eye. Without natural blue-lightblocking mechanisms, the blue light that reaches the retina is sufficiently energetic to initiate oxidative damage, and the retina/retina pigment epithelium complex contains high amounts of photosensitizers (e.g., lipofuscin) with an action spectrum that matches the waveband of approximately 400 to 500 nm (the description of the “blue-light hazard”). Another ramification of filtering light in the visible spectrum is that it alters the incoming stimulus and changes visual function, as has been demonstrated by studies using psychophysical methods to measure the optical density of naturally occurring intraocular BLFs like the anterior lens [6] or macular pigment [7]. Wooten and Hammond [10] originally argued that BLF could influence visual range (how far one can see outdoors) by selectively attenuating the deleterious effects of atmospheric blue haze (see the empirical validation of the original modeling by Hammond and colleagues [11])

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