Glistenings and retinal straylight

In the editorial about microvacuoles in hydrophobic acrylic intraocular lenses (IOLs), 1 Dr. Mamalis succinctly summarized the conflicting evidence on the matter. There seems to be little doubt that the prevalence and intensity of glistenings increases over time in certain hydrophobic acrylic IOLs; in fact, studies have determined that this continues to increase up to 15 years postoperatively.2,3 Glistenings, unless very severe, do not adversely affect visual acuity, modulation transfer function, ultraviolet/visible spectral transmittance, or contrast sensitivity. Because visual acuity usually remains in the 6/6 to 6/9 range, it is hard for most clinicians to rationalize the negative impact of glistenings on visual function. However, glistenings do adversely affect visual function in that they create forward light scatter (retinal straylight).A In patients, retinal straylight produces complaints of hazy vision, increased glare hindrance, loss of contrast and color, halos around bright lights, and difficulties with against-the-light face recognition. Forward light scatter does not correlate to visual acuity and makes patients miserable despite having Snellen acuity of 6/6 to 6/9. Because of their negative impact on driving ability, straylight levels have been advocated for consideration in determining the need for ocular surgery.4–6 The number of adverse reports to the U.S. Food and Drug Administration regarding glistenings has increased in recent years. It is not surprising that in this age of striving for quality in vision, patients with microvacuoles are benefiting from IOL exchange despite having 6/6 visual acuity.7 As Dr. DJ Apple has so aptly deduced, “One is justified in asking… [w]hy implant… [a] lens when the potential for… [glistenings]… exists, if there is an equivalent-quality IOL available that carries out all functions of the lens but is not encumbered with glistenings?”B