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Consider angle kappa measurement, spherical aberration when making premium IOL selection
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NEW YORK — Surgeons need to pay particular attention to angle kappa and spherical aberration when selecting multifocal and accommodating IOLs, a speaker said here.
Mitchell A. Jackson, MD, shared pearls on effective IOL selection at OSN New York 2012.
“Decentration, image quality, depth of field, angle kappa and spherical aberration all have a say in final input of IOL selection,” he said.
Spherical aberration stems from aperture error. In a traditional spherical IOL, lens power increases from the center to the edge. In a lens with zero spherical aberration, power is uniform at the visual axis and periphery. In a lens with negative spherical aberration, power decreases from the center to the edge, Jackson said.
A traditional monofocal IOL provides the worst image quality, a zero spherical aberration lens provides good quality, and a lens with negative spherical aberration provides the best quality.
Angle kappa involves a discrepancy of up to 0.37 mm between the foveal axis and pupil center, Jackson said. Angle kappa of more than 0.4 mm has a particularly strong influence on vision.
A cataract patient with high angle kappa should receive an aspheric IOL with zero spherical aberration. A patient with low to normal angle kappa for whom depth of field is a critical criterion should receive an aspheric IOL with zero spherical aberration. A patient with low to normal angle kappa for whom image quality is critical should get an aspheric IOL with negative spherical aberration, Jackson said.
Disclosure: Jackson is on the speakers bureau of Abbott Medical Optics, Alcon, Allergan, Bausch + Lomb, Technolas Perfect Vision and Marco. He is a consultant for Cynacon/Ocusoft and Hoya. He is on the advisory boards of Noble Vision Group and ACE Vision Group. He is a shareholder in Paragon BioTeck.