Presenter: Dr. Rahul Achlerkar
Moderator: Dr. Vijay Shetty
You've just performed successful, uncomplicated
Your patient is 20/20 and the surgery looks beautiful
you're ready to be congratulated.
Instead, your patient says, "I hate it! These
unwanted images are driving me
crazy! You've got to do something
Of course, this isn't what you want to hear.
But the reality is that dysphotopsia has become the
number one problem following uncomplicated,
successful cataract surgery.
And it doesn't go away easily once a patient becomes
focused on it.
Unfortunately, many of these patients are incredibly
most of whom have told that they're crazy.
"Your surgery is perfect,". "There's nothing wrong
This has entirely the wrong effect, making the patient
angrier and even more focused on the unwanted
The Nature of the Problem
The no.of patients who actually require an intraocular
lens exchange is only about 1 in a 1000
However, the number of patients complaining about
dysphotopsia is closer to 1 in 10
So what's behind the current wave of dysphotopsia
The first element is what the patient is actually seeing.
The second element is how the patient reacts to the
the patient's reaction can be the most significant
factor in resolving (or not resolving) the problem
What the Patient Sees
- temporal darkness
- a central flash
In the literature, terms such as
have been used to describe these images.
In June 2000, the term “dysphotopsia” was first used
is usually related to bright artifacts of
light on the retina
is manifested by a dark crescent or
The exact etiology of negative dysphotopsia remains
The question of why this dark shadow of light occurs
because the nasal retina may extend further anteriorly
than the temporal retina as well as because light
coming in nasally may be somewhat tempered by the
nose, eyebrow and cheek
However, light coming from the temporal side of the
eye that projects to the nasal-most retina may be
deflected by the edge of the IOL or even reflected
internally by the relatively square edge of the IOL
away from the nasal retina.
This results in a crescent-shaped shadow noted in the
temporal field of vision.
• Temporal darkness
temporal darkness, or negative dysphotopsia, is the
most prevalent symptom today.(30 to 40 %)*
In this case, the patient detects a black shadow
temporally, in the periphery of vision.
*Vámosi P, Csákány B, Németh J. Intraocular lens exchange in
patients with negative dysphotopsia symptoms. J Cataract Refract Surg.
patient perceiving the edge of the IOL, which usually
only happens at night.
It's a common complaint and rarely a serious
It usually resolves over time—especially if the capsule
overlaps the IOL edge.
This is also a scotopic symptom produced by coma.
Correcting minimal cylinder with night driving
glasses will often get rid of it.
Making the pupil a little smaller at night will also
this appears to be caused by a peripheral light source
reflecting off the internal edge of the IOL
Recent advances in edge design have minimized this
These may be caused by a multifocal IOL
produces haloes around lights from each ring
Most patients will adapt to this, and a smaller
scotopic pupil can help in the meantime.
night haloes are the number one reason these IOLs
If patients see haloes with a monofocal IOL, it usually
indicates the presence of spherical aberration.
new aspheric-optic IOLs will help
How the Patient Reacts
Difficult to eliminate all unwanted images from
The brain is adapt at eliminating unwanted visual
input by phenomenon of central adaptation.
the most obvious example is the hole in
our visual field where the optic nerve enters the eye.
In addition, we get
-front- and backscatter off our natural lens,
- pupils are irregular,
-blood vessels in our retina
that we can't see through.
there are a lot of unwanted images in our field of
vision, but our brain adapts and eliminates them all.
it's inevitable that some patients will experience
In these cases, doing the right things before and after
surgery can avoid the greater problem
• Create accurate expectations
Explain to patient about dysphotopsia pre operatively
Then, the patient won't be surprised if some new,
unwanted visual effect accompanies the new lens
Minimize the problem surgically
1 Use the right lens
Certain IOL characteristics appear to correlate with
Newer lenses have helped by increasing the front
curvature of the lens, which minimizes front and back
Optic size is important, because a smaller lens may
create more edge problems.
d0n't implant a lens any smaller than 6 mm
All the IOLs studied variably
increased internal and external
surface reflections when compared
to the human crystalline lens.
SQUARE EDGE DESIGN
While the square-edge optic is clearly favored for
reducing the risk of PCO, the trade-off for that
benefit is an increased rate of pseudophakic
square-edged optic is one responsible factor causing
The other factors responsible are
- the index of refraction of the IOL material,
- corneal curvature
- pupil size.
Truncated posterior edge offers barrier effect to
lens epithelial cells
Sloped edge-minimises internally reflected rays
that form arc like images
Rounded anterior edge- eliminates mirror effect
Round edge of the optic causes greater dispersion of
the internally reflected rays of light, reducing edge
glare by 90 percent
Increasing the front curvature of the Newer lenses has
helped minimize front and back light scattering,
Double square edge
When light hits the double-square edge Lens
at 23 degrees, little edge glare.
at 35 degrees, one begins to see arcs
at 55 degrees, transmitted as well as reflected glare
becomes significantly more evident.
silicone lens with a rounded edge and lower
refractive index seems to be most forgiving,
producing the fewest complaints about unwanted
2. Place the lens carefully
A well-centered, in-the-bag lens prevents unnecessary
3. Overlap the capsulorhexis rim over the edge of the
The edge of the capsulorhexis will tend to opacify
the opaque overlap will eliminate many symptoms
associated with the edge of the IOL.
The brain seems to ignore the edge of the capsule,
reacting as it does to the edge of the pupil.
another major benefit
This strategy has another major benefit
If we overlap the capsule, we will significantly decrease
posterior capsule opacification.
Two recent studies, show that overlap of the capsule is
more effective at preventing "aftercataract" than
switching to an IOL with a truncated edge
Making a smaller capsulorhexis has some potential
It can be more difficult to access the lens, particularly if
we use the Phaco technique.
Also, we don't want to risk capsular contracture by
making the opening too small
To minimize dysphotopsia and PCO, the opening
should be roughly 1 mm smaller than the size of the
optic, to ensure 360-degree overlap
And use at least a 6-mm optic
After surgery, don't take the wrong
attitude if a patient complains
The worst thing you can do if a patient complains is
"Your result is perfect. Nobody else is complaining.
What's your problem?"
This virtually guarantees that the patient will "turn up
the gain," and fail to adapt to the unwanted images.
Resolving a Dysphotopsia Crisis
Talk to the patient (and say the right thing).
First of all, let the patient know that he/she's not
crazy. That alone will improve matters.
Try night time pupil constriction
don't open the capsule
Whatever you do, don't open the capsule
Some ophthalmologists, thinks May be patient got
So let's go ahead and do a YAG capsulotomy and see if
that will make it better
if the problem truly is dysphotopsia, a capsulotomy
won't have any positive effect at all
When we try to take the lens out after a YAG
capsulotomy, vitreous comes forward.
we often can't put the lens back in the capsule
because the capsulotomy tears further.
The risk of endophthalmitis and retinal detachment
lens exchange ???
• Only resort to lens exchange if it really makes
First of all, make sure the patient has had enough
time to adapt.
If even after six months problems continued then a
lens exchange can be consider —only if it improve on
the existing lens situation.
Otherwise, switching lenses will be a waste of time.
Factors deciding lens exchange
1. The size of the existing capsulorhexis
If the optic is small then larger optic will create more
overlap of the edge, this can solve problem
2. Edge design
If the current IOL doesn't have an up-to-date edge
design, then switching to an updated lens would be
3 Refractive index
If the current lens has a high refractive index,
switching to a rounded-edge silicone lens may be
curative, particularly if there is negative dysphotopsia.
4 Condition of the capsule
If another surgeon has performed a YAG capsulotomy,
a lens exchange will involve more risk.
If all else fails
For some patients,nothing will relieve the symptoms,
and IOL exchange may not make sense if the patient
already has the most beneficial type and size of IOL.
In that case, talk to the patient again and do best to
help him or her to relax
and adviced to stop thinking about it so much, so the
brain has a chance to adapt.
Pseudophakic Dysphotopsia with
Various Intraocular Lens
One study was conducted in our institute on
Pseudophakic Dysphotopsia with Various
Highlights of study
1)The incidence of dysphotopsia found to be 51.12%
2) The incidence of negative dysphotopsia has been
found to be 22.47%
3)The eyes implanted with Tecnis ZCB00 IOL showed
less negative temporal shadow/darkness
4) Hydrophilic Acrylic IOLs showed greater
dysphotopsia score in comparison to those with
5) Hydrophilic versus Hydrophobic Acrylic, the latter
was found to be significantly better with a lower
6)Hydrophobic Acrylic IOLs when compared to
Hydrophilic Acrylic IOLs and Silicone IOLs showed
decrease in night-time glare/halo/circles
7) An increase in the optic-haptic angle caused an
increase in night-time glare/halos/circles around
Tecnis ZCB00 emerged as least troublesome lens
while Auroflex FH5575 which was reported to have
the highest Dysphotopsia.
Hence, we may conclude that different
brands of intra-ocular lenses display varying degrees of
new hypothesis, resolution of negative dysphotopsia
symptoms depended on intraocular lens (IOL)
coverage of the anterior capsule edge rather than on
collapse of the posterior chamber alone.
Negative dysphotopsia was not attributed to a
particular IOL material or edge design
Pseudophakic negative dysphotopsia: Surgical management
and new theory of etiology
Journal of Cataract & Refractive Surgery, 06/24/2011
Two rays, coming in from
the temporal side at 90°,
are bent by the cornea by
As they come through,
one ray, if there is a space
between the iris and the
anterior surface of the
lens, can miss the front
part of the lens
Hawaiian Eye meeting, Jack Holladay,
while the other ray hits
the lens and is bent by the
lens's refractive power.
In the cone between those
two rays, no light can
enter, and this causes what
is perceived by the patient
as a crescent-shaped
*Dr. Holladay said
Hawaiian Eye meeting
In the first day after IOL implantation, approximately
15% of patients experience negative dysphotopsia. By
3 years, the phenomenon is reduced to only 5%
To treat negative dysphotopsia, we have to eliminate
the rays that pass anterior to the IOL
and to do so we have to reduce the space between the
iris and the anterior surface of the IOL*
* Dr. Holladay said.
This reduction may occur spontaneously in some
cases with the natural forward movement of the IOL
after capsular bag contraction.
The opacification of the equatorial capsule, occurring
naturally several weeks or months after implantation,
is also likely to reduce the shadow effect.
we can otherwise flip the optic, though this might
can implant a piggyback IOL in the sulcus. Frosted-
edge IOLs are another solution
Two surgical strategies have emerged as beneficial
treatment of persistent visual symptoms of ND:
reverse optic capture (ROC)
secondary “piggyback” IOL.
Failed surgical strategies include bag/bag IOL
exchange wherein the original implant is removed
and another of different material, shape or edge
design is replaced within the capsular bag.*
* This is in keeping with the work of Vámosi et
Reverse Optic Capture
ROC may be employed in a secondary surgery for
symptomatic patients, or as a primary prophylactic
In cases of the latter, the method has been applied to
the second eye of patients who were significantly
symptomatic following routine uncomplicated
surgery in their first eye.
It should be noted, however, that ND symptoms are
not necessarily bilateral.
Secondary ROC, performed for symptomatic patients,
may be applied if the anterior capsulotomy is not too
small or too thick or rigid from postoperative fibrosis.
The first step involves freeing the anterior capsule
from the underlying optic by gentle blunt dissection
Gentle blunt dissection and
viscodissection of the anterior capsule
from the underlying optic
Next, the nasal anterior capsule edge is retracted with
one Sinskey hook (or similar device) while the optic
edge is elevated and the capsule edge allowed to slip
under the optic.
This maneuver is repeated 180 degrees away
temporally, leaving the haptics undisturbed in the bag
inferiorly and superiorly.
A Sinskey hook and blunt spatula
are used to elevate the nasal optic
edge over the capsule
the haptics be oriented horizontally, it would be best
to rotate them 90 degrees if possible
The optic is then confirmed to be elevated over the
anterior capsule edge and the nasal and temporal
edges of the implant are anterior to the anterior
capsule, whereas the haptics remain within the
Optic capture has
The nasal and
temporal edges of
the implant are
anterior to the
fully within the
Once the nasal
edge has been
temporal edge of
the optic is
elevated over the
Secondary “Piggyback” IOL
Secondary “piggyback” IOL is the other surgical method
that has proven successful for patients with symptomatic
ND, as first reported by Ernest.
In this method, a second IOL is implanted in the ciliary
sulcus above the primary IOL/capsule bag complex.
It appears that covering the primary optic/capsule
junction reduces ND symptoms
although the original concept was that a
“piggyback” lens was effective because it collapsed
the posterior chamber by reducing the distance
between the posterior iris and the anterior surface
of the IOL.
However, studies *have determined that the
depth of the posterior chamber is unrelated to ND
*Vámosi et al.,march 2011
Symptomatic patients may be good candidates for
a “piggyback” IOL if they are also ammetropic.
In order to qualify for a “piggyback,” the first IOL
surgery should be uncomplicated with a well-
centered IOL within the capsule bag.
There should be no evidence of zonulopathy and
the iris must be free of defects or damage from
Although no parameters have been clearly
established, it ia better to perform a UBM to
ascertain adequate space (approximately 1 mm)
between the posterior iris and the existing
There are two kinds of light- the glow that illuminates
and the glare that obscures.