Transcript Retina Grand Rounds - ASCRS/ASOA 2009

Managing the
Refractive “Surprise”
After Toric IOL Placement
Brad H Feldman, MD
Derek DelMonte, MD
Alan N Carlson, MD
Duke Eye Center
Durham, NC
Authors have no financial interests
Case Presentation
53 year-old man referred to the Duke Eye Center for
2nd opinion regarding residual astigmatism after
undergoing cataract extraction with Toric IOL left eye
Patient originally chose Toric IOL on surgeon
recommendation to achieve astigmatic neutrality and
decrease spectacle dependence
Patient completely unsatisfied with outcome
immediately after surgery
Surgeon indicated there was nothing more he could
offer the patient
Prior Ocular History
Note: patient underwent myopic LASIK
OU in 1999 with monovision OS
– Pre-LASIK OS MRx: -6.75 +1.25 x 080
– Post-LASIK OS MRx: -1.50 sphere
Cataract noted in August 2007 with BCVA
of 20/50 OS
– OS MRx: -3.00 –1.25 x 170
Prior History Continued
Pre-Cataract Surgery Evaluation OS
April 2008 (Still at Outside Facility)
– MRx:
-2.75 -1.00 x 170
BCVA: 20/60
– Orbscan Keratometry:
42.90/43.70 x 098
+ 0.8D x 098
– IOL Master K Values:
42.13/43.21 x 092
+1.1D x 092
– Manual Keratometry 40.20/42.20 x 098
+2.0D x 098
– US Pachymetry
479 microns
IOL Calculations: (Outside Facility)
Patient chose Toric “Premium” Lens
Lens Power:
– IOL Master Derived
– SRK/T Clinical History Method
Astigmatism Power:
– Alcon AcrySof Toric Calculator Used
– Based on Manual K’s
As per instructions of online calculator
Note difference in power of K axes between
Orbscan, IOL Master, and Manual K’s (see prior
slide)
IOL
Calculations
Postoperative Course
UCVA 20/60; plano –2.50 x 100 = 20/20
Examination
– Axis flipped despite properly achieving the intended axis
– Position: asymmetric fixation, superior loop in sulcus,
inferior loop in bag, optic decentered superiorly and tilted
Assessment:
– Pantoscopic tilt with optic decentration making astigmatic
correction by the IOL overly effective, causing over
correction and axis flip
Plan: Reposition lens for symmetric bag fixation
– Please view attached video for details
Post-Repositioning Course
UCVA 20/60
MRx:
+0.75 –2.75 x 100 = 20/20
Examination
– Reveals correct Toric IOL position, centration, & axis
– Atlas Topography:
42.50/42.62 x 090
+0.12 x 090
– Pentacam Holladay Equivalent Ks (4.5mm zone):
42.00/42.90 x 110
+0.90 x 110
Post-Repositioning Course
Our initial assessment in consultation supported an
improperly implanted IOL as the culprit for the
astigmatic axis flip.
The patient’s outcome after his second surgery
indicates the original IOL selection error was based
on using a post-LASIK manual “K” reading.
Additional data revealed this was inconsistent with
other astigmatism measurements.
Patient remains frustrated and is now contemplating
IOL exchange.
Discussion
The differential diagnosis for a “surprise” result
after surgery includes:
– Wrong astigmatic power calculation and IOL
selection
– Incorrect astigmatic axis alignment
– Incorrect Toric IOL location resulting from
decentration or optic tilt
– Surgical or postoperative induction of astigmatism
related to wound healing or IOL optic rotation
Summary
53 yo h/o LASIK unsatisfied due to astigmatism
following cataract surgery with Toric IOL
– Toric IOL was selected on the basis of manual “K” readings as
recommended by IOL selection protocol
– Original measurements were inconsistent:
IOL Master ≠ Orbscan ≠ Pentacam ≠ Manual “K”’s
Our error was attributing the initial surgical outcome
entirely to faulty IOL fixation and position
– There was optic tilt and decentration secondary to asymmetric
capsular fixation from the original surgery
Astigmatism remained despite proper repositioning
– This suggests the original surgeon used manual “K” readings which
were incorrect after previous LASIK surgery
Conclusion
Measuring corneal astigmatism after refractive surgery
requires multiple methods and more critical analysis for
consistency before recommending astigmatismcorrecting Toric IOLs.
Critical analysis and caution are warranted when
considering a Toric IOL in cases having discrepancies
between different methods of “K” readings