CATARACT: SURGICAL PEARLS
From the 28th Annual UC Davis Ophthalmology Symposium, Cataract Surgery from A to Z (And Beyond), presented
May 13-14, 2005, by the UC Davis Health System
Randall J Olson, MD, the John A. Moran Presidential Professor and Chair of Ophthalmology and Visual Sciences,
Director, John A. Moran Eye Center, University of Utah, Salt Lake City
| PSEUDOPHAKIC DYSPHOTOPSIA
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| General: pseudophakic dysphotopsia number one cause of patient dissatisfaction in uncomplicated cataract
surgery; question whether all dysphotopsia edge-related
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| Causes: patient factors—scotopic pupil; myopia; physical obstruction (what blocks images); light colored irides;
central adaptation—greatest patient-related cause of pseudophakic dysphotopsia; brain acts as analog
computer with variable gain (people analyze impulses and adjust them to enhance neural pathways); people
with hair-trigger variable gain (obsessive-compulsive traits); reassurance and explanation important (before
patient becomes angry and turns up internal gain); surgical factors—intraocular lens (IOL) dislocation; optic
too small for patient; anterior capsular overlap; higher order aberration; surgeon’s response to complaints;
IOL factors—optic size; untreated truncated edge; refractive index; induced spherical aberration; multifocality
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| Symptoms: arc—IOL edge seen; large pupil (guaranteed); anterior capsule opacification (really helps); far
peripheral light rays cause this to persist; rarely real problem (discuss occurrence as probability); halos at
night—very common; spherical aberration correlation; annoying but rarely real problem; constriction of
pupil helpful to decrease symptom (brimonidine [Alphagan]); flare—common for peripheral lights; cylinder
correction helpful in eliminating symptom; constriction of pupil helpful in decreasing symptom; peripheral
light causing central flash—untreated truncated edge; symptom tends to not get better; IOL exchange
common; shimmering/pulsing light—often worse during day; common complaint; front and back scatter;
flat anterior curvature and high refractive index (accentuates scatter); catadioptric image; phenomenon synchronized
with microsaccades (light moves back and forth opposite microsaccades; if above brain threshold,
patient will see light as pulsing or shimmering); pupil size adjustment does not help; IOL exchange
possibly necessary; temporal darkness—biggest problem today; complex phenomenon; peripheral light rays
hit edge of lens, producing scatter that gets confused by brain and overwhelming peripheral vision; grey
spot seen temporally because nose blocks images nasally; varies in size and intensity with movement of
head; common phenomenon in early postoperative period, particularly in high refractive index lenses; pupil
constriction rarely helps; most frequent cause of IOL exchange today for pseudophakic dysphotopsia
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| Multifocality: improved with new lenses; Array lens moderate to severe symptoms (>50% of patients);
with ReZoom and ReSTOR, ≈30% of patients have symptoms
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| Brands and differences in edges of IOLs: Acrysof—increased anterior curvature; milled edge; temporal
darkness; refractive index unchanged; OptiEdge—small truncated area, then rounded off (idea that more
light dispersed to help ameliorate images, but impact of truncated edge remains); Bausch and Lomb—
angled edge so that still truncated, but most of reflection in peripheral retina; Sensar-E vs SA-60 and
dysphotopsia—patient with SA-60 in one eye had pulsing vision and temporal darkness; Sensar-E put in
second eye; SA-60 later replaced with Sensar-E in first eye to reduce dysphotopsia; Franchini study—
looked with laser ray tracing strength of images with different edge designs; if Acrysof (untreated edge)
given value of 10; new Acrysof has value of 8, truncated silicone has value of 6, Optiedge has value of 3,
and round edge has value of 1; 10-fold variation; Optiedge not as good as rounded edge for edge-related
symptom
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| Study: outcomes questionnaire; uncomplicated surgery; no macular pathology; 20/25 vision; average 2-
yr follow-up (no one <1 yr); 40 aged-matched normal (no cataracts) people >65 yr of age; question of
unwanted images off to side of light source causing problems—minimal problems in control group, but statistically
significant problems with lens with untreated truncated edge; question of temporal darkness—
no problem in control group, but all lenses had problem, regardless of type of edge (power of image
related to refractive index); question of problems with oncoming headlights at night—optic size issue; question
of light to side causing central flash (classic edge-related phenomenon)—lens with untreated truncated
edge has most problems; results show control (own eyes) best; conclusions—edge design most important;
optic size next; refractive index (in treated-edge lenses) biggest cause of problem images; all
lenses worse than control; satisfaction issue; do not be quick to exchange IOL; do not use yttrium aluminum
garnet (YAG) laser on capsule in pseudophakic dysphotopsia; number one cause of dissatisfaction;
not just IOL (central adaptation important); waiting and constricting pupil for some symptoms
(not shimmering vision)
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| Wound burn with phacoemulsification (phaco) machines: principle—peak velocity of stroke length of
ultrasound needle 50 mph (creates friction); with no-flow situation, can go from room temperature to
100ºC in 1.5 sec; threshold for burn ≈60ºC; eye full of ophthalmic viscosurgical device (OVD) can block
all flow; always do irrigation and aspiration (IA; to remove viscoelastic) before beginning procedure
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| Machine thermodynamics in vitro—study of 60-sec temperatures; 5 runs at each setting (hundreds of settings);
temperature reduced to increase in degrees centigrade over 60 sec per 20% power change (each parameter
had 25 runs; had to cool down to baseline temperature before next run; P <0.0001 unless otherwise
noted); in water, temperature increase per 20% power change at continuous power level and pulse level,
Sovereign 2.3 times hotter (ie, dynamic range in water that at 100% power for Legacy equals same temperature
output as 43% power with Sovereign); percent power meaningless; duty cycle—extremely precise; 50
ms on and 50 ms off (50% duty cycle) compared to continuously on, got 47.8% of heat with Sovereign
pulse and 49.4% heat with Legacy pulse (if on half time, get half heat production); 6 ms on and 12 ms off,
got 35.6% heat (Sovereign White Star [WS]); energy related to duty cycle, not length of on time; Sovereign
WS with 0.356 continuous energy multiplied by 2.3 (times hotter) divided by 0.494 (Legacy) = 1.66 (Sovereign
WS 1.66 times hotter at 50% than Legacy); must define variables when making comparisons; blocked
line—dramatically increases heat (2- to 3-fold); weighted/ unweighted ratios—hung weights off sleeve in controlled
fashion; used 100-g and 200-g weights, looking at effect on temperature; Legacy with 100 g had
52% increase in temperature; Sovereign increased 15% (P = 0.007); Legacy with 200 g, went from
50% to 115% increase; Sovereign went from 15% to 23% increase; 8-fold difference in temperature increase;
power systems dramatically different; cruise-control analogy—set cruise control at 50 mph, very little
gas going down hill (like working in air); traveling level (like working in water); going up hill, surge
power to maintain speed; if machine set at 50% (50% of set stroke length), power will vary; Sovereign and
Millennium like gas pedal (push on gas, go fast down hill, go slow up hill); makes difference with hard
fragment, surge of power might take over threshold; conclusions—percent power meaningless; laws of
thermodynamics followed; of continuous, blocked, and loaded, loaded riskiest; question as to whether
“cruise” power control riskier; thermal inertia—study looking at whether propagation of heat in tissue
(thermal inertia) different from in vitro; compared in vitro temperature increases after 20 sec to same
thing in fresh eye-bank eye, 200 µm from wound; ultrapulse in vivo at 6.505+/- 0.65ºC; pulse in vivo
showed 10.1% difference (P = 0.0017); propagation in tissue in very short pulses 10% less than predicted
in vitro; near misses common, and 10% could have much bigger impact than expected; increasing power
would minimize duty cycle effect; if enhancing transient cavitation, need less power to get job done; minimizing
microchatter effect so that with each pulse, more work done (using less power)
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| Wound burn survey: contracture or folds present (significant wound burn); 76,000 wounds showed overall
incidence of 1 in 1000 (Rocky Mountain area), 53 (71%) during fragment removal; only 32% of surgeons felt
tip occluded at time of burn; feature differences—incidence of wound burn less with Sovereign and Millennium
than with Legacy; incidence of wound burn 1 in 4000 with vertical chop; approach differences—
incidence 1 in 1800 with horizontal chop; incidence 1 in 800 with divide-and-conquer technique and carousel;
kind of energy—1 in 4000 with White Star, 1 in 1200 with burst, 1 in 800 with pulse, 1 in 550 with continuous;
multivariate analysis—most important feature ultrapulse; vertical chop second most important feature;
must be more than duty cycle; thermal inertia important; efficiency
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| Prospective evaluation: reported on Legacy divide-and-conquer; continuous with some pulse; 12.6% incidence
of wound burns; 8% incidence with Infiniti
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| Considerations: 1 in 1000 low for some practices; no clue of temperature until burn occurs (want to prevent
getting to 60ºC); in segment removal, must use ultrasound plus vacuum to get piece out, causing dilemma
(should use ultrapulse); tight wounds increase friction and can decrease flow; twisting in wound increases
friction; harder nucleus needs increase in power; combination of chop and ultrapulse very protective
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| UNDERSTANDING THE NEW LENS REMOVAL TECHNOLOGIES
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| Phaco chop: available from 3 major companies; short pulses of energy; mechanical forces emphasized; ultrasound
only to assist in aspiration; more efficient; safety—overall, minimizing energy safer; capsular
breakage advantage tough to study (speaker decreased own capsular breakage rate 2- to 3-fold);
disadvantages—zonular breakage; American Academy of Ophthalmology course on chop
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| Ultrapulse: short pulses; wound burn risk decreased; enhanced transient cavitation (more efficient); microchatter
smoothed out; followability improved; works with any technique; no learning curve
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| NeoSoniX: oscillatory motion to regular ultrasound; greater cross-sectional area and efficiency of impact;
best for fragment removal; not as good for occlusive hold
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| Aqualase: newest entrant into field; works for up to 1+ to 2+ cataracts; refractive lenses; works on capsule;
polishing; safer for softer cataracts (anecdotal evidence)
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| Conclusions: exciting new techniques and technology; safety will trump efficiency; good studies needed;
eventually, ultrasound will be replaced as main modality
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Educational Objectives
| The goal of this program is to provide the listener with information on pseudophakic dysphotopsia, wound
burn with phacoemulsification, and the new lens removal technologies. After hearing and assimilating this
program, the clinician will be better able to:
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 | 1. Recognize the symptoms and discuss the causal factors of pseudophakic dysphotopsia.
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| 2. Distinguish between edge differences in pseudophakic photopsia.
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| 3. Review dynamics contributing to wound burn in phacoemulsification.
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| 4. Discuss the techniques and technology that can decrease incidence of wound burn in phacoemulsification.
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| 5. Describe the new technology and techniques available for lens removal.
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Discussed on This Program
Brimonidine tartrate [Alphagan, Alphagan P]
Suggested Reading
Arbisser LB: Origin of intraocular metallic foreign bodies during phacoemulsification. J Cataract Refract
Surg 31:2423, 2005; Bradley MJ, Olson RJ: A survey about phacoemulsification incision thermal contraction
incidence and causal relationships. Am J Ophthalmol 141:222, 2006; Davison JA: Ultrasonic power reduction
during phacoemulsification using adjunctive NeoSonix technology. J Cataract Refract Surg 31:1015,
2005; Fine IH, et al: Power modulations in new phacoemulsification technology: improved outcomes. J Cataract
Refract Surg 30:1014, 2004; Hughes EH, et al: Aqualase for cataract extraction. Eye Nov, 2005; Jin
GJ, et al: Changing indications for and improving outcomes of intraocular lens exchange. Am J Ophthalmol
140:688, 2005; Jiraskova N, Rozsival P: Phacoemulsification parameters: series 20000 Legacy Versus
Legacy with AdvanTec software abd NeosoniX handpiece. J Cataract Refract Surg 30:144, 2004; Nawrocki
J, et al: Cool phaco—new option in cataract surgery. Klin Oczna 107:36, 2005; Rose AD, Kanade V: Thermal
Imaging Study Comparing Phacoemulsification With the Sovereign With WhiteStar System to the Legacy
With AdvanTec and NeoSoniX System. Am J Ophthalmol 141:322, 2006; Schwiegerling J: Recent
developments in pseudophakic dysphotopsia. Curr Opin Ophthalmol 17:27, 2006; Shambhu S, et al: The effect
of lens design on dysphotopsia in different acrylic IOLs. Eye 19:567, 2005; Spencer M: Phaco vs. small-
incision. Ophthalmology 113:353, 2006; Vasavada AR, et al: NeoSonix ultrasound versus ultrasound alone
for phacoemulsification: randomized clinical trial. J Cataract Refract Surg 30:2332, 2004.
Faculty Disclosure
In adherence to ACCME guidelines, the Audio-Digest Foundation requests all lecturers to disclose any significant
financial relationship with the manufacturer or provider of any commercial product or service discussed.
The following has been disclosed: Dr Randall is a consultant for Advanced Medical Optics, Inc.
Dr. Randall was recorded at the 28th Annual UC Davis Ophthalmology Symposium, Cataract Surgery from A to Z
(and Beyond), held May 13-14, 2005, in Sonoma, California, and sponsored by the University of California,
Davis, Health System, Departments of Ophthalmology & Vision Science and Continuing Medical Education.
The Audio-Digest Foundation thanks Dr. Randall and the sponsor for their cooperation in the production of
this program.
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