Compromised optical quality seen with localized central IOL opacification

A laboratory-based study compared modular transfer function (MTF) in IOLs with 1 of 2 distinct IOL opacification patterns vs. IOL controls.

Study design

This laboratory-based German study was designed to evaluate how different types of IOL opacification affect the function of the lenses, and how the MTFs measure the ability of a lens to transfer contrast at a particular resolution from an object to the retina. Sixty-seven explanted IOLs with calcifications were evaluated for 1 of 2 types of opacification/calcification patterns: a primary pattern characterized by a band of fine granular deposits distributed under both the anterior and posterior surfaces of the IOL (homogenous), and a secondary pattern characterized by calcification at the anterior IOL surface with a central pattern seen only in the pupillary area (localized central).

Outcomes

Of the 2 types of opacification patterns (and the control group), only the localized central group showed an MTF reduction that would likely affect patient visual acuity. Both the localized central and homogenous opacifications were likely to cause glare symptoms.

Limitations

Although the study does demonstrate compromise to the optical quality when calcifications are present on an IOL, the testing was performed after explantation. To determine whether a lens with calcifications causes optical phenomena in vivo, information on how to appropriately assess patients is needed. The study suggests glare and straylight testing in the office, if possible.

Clinical significance

It is important to remember that when patients express a decline in their vision in the setting of IOL calcifications, the lens itself should be evaluated as a possible cause of the symptoms. Even when a patient has reasonable visual acuity, the quality of vision may be poor due to the opacifications.