Following cataract surgery, patients can present with a variety of visual complaints that interfere with vision after IOL implantation. Negative dysphotopsias are relative and absolute scotomas, according toJack T. Holladay, MD.
Boston — Following cataract surgery, patients can present with a variety of visual complaints-i.e., dysphotopsias, aberrant optical phenomena that interfere with vision after IOL implantation.
Positive dysphotopsias include rainbows, streaks, crescents, rings, halos, and veiling glare, haze, and fog. Negative dysphotopsias are relative and absolute scotomas, said Jack T. Holladay, MD.
“The patient’s specific symptom can identify the anatomic location in the patient’s optical system that tells the physician where it is and how to treat the patient,” said Holladay, during Cornea Day at the annual meeting of the American Society of Cataract and Refractive Surgery.
For streaks, high plus cylinder is the first cause to be considered. Treatment is opening the capsule to address the proliferative lens fibers that are causing the streaking.
When the complaint is crescents, the IOL is decentered and light is coming through the aphakic pupil and the IOL. Rings are specific to refractive multifocal IOLs, noted Dr. Holladay, Baylor College of Medicine, Houston.
Chromatic halos-rainbows-usually result from small spheres of water in the epithelium and indicate elevated IOP.
Microcystic edema and a femtosecond laser spot pattern resulting from use of an older femtosecond laser are less common causes of halos. A decentered diffractive multifocal IOL can cause halos.
Glare, haze, and fog result from scattering of light that is diffused as a result of lens fibers or foamy degeneration of epithelial cells.
Veiling glare results from glistening formation in the IOL. Positive dysphotopsias can also result from missing rays from internal reflections and the anterior or posterior sharp IOL edge.
With negative dysphotopsias, patients see a temporal, dark, crescent-shaped shadow in the peripheral that increases with bright light and usually resolves in 80% of cases in 2 years.
Treatments include removing the nasal annulus of the overlying anterior capsule, placing the shoulders of the haptics horizontally with the one-piece IOL, exchanging the IOL for a rounded-edge silicone IOL, implanting a secondary piggyback IOL in the sulcus, reversing optic capture, and iris suture fixation of the capsule bag IOL complex.