2020–2021 BCSC Basic and Clinical Science Course™
3 Clinical Optics
Chapter 6: Intraocular Lenses
Lens-Related Vision Disturbances
The presence of IOLs may cause numerous optical phenomena. Various light-related visual phenomena encountered by pseudophakic (and phakic) patients are termed dysphotopsias. These phenomena are divided into positive and negative dysphotopsias. Positive dysphotopsias are characterized by brightness, streaks, and rays emanating from a central point source of light, sometimes with a diffuse, hazy glare. Negative dysphotopsias are characterized by subjective darkness or shadowing. Such optical phenomena may be related to light reflection and refraction along the edges of the IOL. High-index acrylic lenses with square or truncated edges produce a more intense edge glare (Fig 6-11A). These phenomena may also be due to internal re-reflection within the IOL itself; such re-reflection is more likely to occur with materials that have a higher refractive index, such as acrylic (Fig 6-11B). With a less steeply curved anterior surface, the lens may be more likely to have internal reflections that are directed toward the fovea and are therefore more distracting (Fig 6-11C, D).
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Davison JA. Positive and negative dysphotopsia in patients with acrylic intraocular lenses. J Cataract Refract Surg. 2000;26(9):1346–1355.
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Erie JC, Bandhauer MH. Intraocular lens surfaces and their relationship to postoperative glare. J Cataract Refract Surg. 2003;29(2):336–341.
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Franchini A, Gallarati BZ, Vaccari E. Computerized analysis of the effects of intraocular lens edge design on the quality of vision in pseudophakic patients. J Cataract Refract Surg. 2003; 29(2):342–347.
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Henderson BA, Geneva II. Negative dysphotopsia: A perfect storm. J Cataract Refract Surg. 2015;41(10):2291–2312.
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Holladay JT, Zhao H, Reisin CR. Negative dysphotopsia: the enigmatic penumbra. J Cataract Refract Surg. 2012;38(7):1251–1265.
Excerpted from BCSC 2020-2021 series : Section 3 - Clinical Optics. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.