I
INNOVATIONS IN LENSES
N FOCUS
110 | EYEWORLD | APRIL 2019
by Rich Daly
EyeWorld Contributing Writer
Contact
information
Miller: kmiller@ucla.edu
Masket: avcmasket@aol.com
Holladay: holladay@docholladay.com
Needed IOL innovations
Illustration of the origin of negative dysphotopsia (ND) and one of many positive dysphotopsias (PD). Light entering a
pseudophakic eye from the temporal periphery can strike the square edge of an IOL if it is sitting far enough behind the
pupil and its optic diameter is sufficiently small. Some light from a polished, square edge design will reflect and strike the
temporal retina, producing one of the many PDs. Light that reflects off the edge is not available to traverse the edge,
leading to an arc-shaped shadow over the nasal retina, which causes ND.
Source: Kevin M. Miller, MD
continued on page 112
A
mid the growing number and variety
of IOLs, surgeons see key areas where
patient needs remain unmet.
Needed IOL changes that would
not necessitate entire redesigns include
either moving away from acrylic
materials or adding a higher index of
refraction acrylic material, said Kevin M. Miller,
MD.
But the primary IOL design challenge stems
from edge design.
"The thing we know about dysphotopsias is
that they suddenly appeared with the introduction
of the square edge," Dr. Miller said.
Initially, dysphotopsias were linked to both
square edge and higher index refraction materials.
Now square edges are seen as the primary culprit
in regard to positive dysphotopsia.
At a glance
• Research indicates acrylic
IOLs are not driving negative
dysphotopsias.
• Positive dysphotopsias may
be minimized by larger optics,
round edges, and low index.
• Needed IOLs include single-
piece lenses for those patients
below –10 D.
• U.S. surgeons need access to
a lens specifically designed for
placement in the sulcus.
