I have no financial interest in any devices or techniques discussed in this presentation

Rotation of Hydrophobic Acrylic Toric IOL Jonathan M. Davidorf, M.D. Los Angeles, CA April, 2010

Case Report

Initial Evaluation 59 y.o. myopic male presents with decreased vision OS Wears spherical soft CLs Current Spectacles (several yrs old) OD: x168 = 20/60 OS: x163 = 20/60 MR OD: x170 = 20/25+ OS: x025 = 20/40--

Initial Evaluation 1+ nuclear sclerosis OD 2+ nuclear sclerosis OS PVD OS, no retinal pathology OU Patient desires cataract surgery OS only (despite anisometropia), will wear conact lens OD postoperatively until cataract OD progresses

Keratometry (OS) Flat meridian (D) Steep meridian (D) Steep meridian (degree) Corneal cylinder (D) Auto Ks Orbscan Sim Ks IOLMaster Ks Figure 1

IOL Selection (OS) Patient does not mind wearing reading glasses (presbyopic IOLs discussed) Prefers minimizing spectacle/contact lens dependence for distance vision Vector analysis using the AcrSof R Toric IOL Calculator predicted residual astigmatism of 0.51D at 099 degrees using a spherical IOL (Figure 2) (

Figure 2

Perioperative Course (OS) Standard clear corneal incision (2.4 mm), topical, phacoemulsification performed 12.5D Aspheric hydrophobic acrylic IOL (AcrySof R SN60WF) implanted Vsc postoperative day 1 = 20/25 Developed significant posterior capsular opacification, underwent YAG PC 7 months Postop MR: x027= 20/20

Follow-up Evaluation Patient now has complaints of decreased vision OD Corrected distance vision 20/50 OD 2+ NS, 1+PSC OD Patient desires cataract surgery OD

Keratometry (OD) Flat meridian (D) Steep meridian (D) Steep meridian (degree) Corneal cylinder (D) Auto Ks Orbscan Sim Ks IOLMaster Ks Figure 3

IOL Selection (OD) Patient still does not mind wearing reading glasses (presbyopic IOLs discussed) Still prefers minimizing spectacle/contact lens dependence for distance vision Vector analysis using the AcrSof R Toric IOL Calculator predicted residual astigmatism of 0.39D at 109 degrees using the lowest power toric IOL (Figure 4) (

Figure 4

Operative Course (OD) Coaxial phacoemulsification (2.4mm CCI) 12.0D hydrophobic acrylic toric IOL (AcrSof R SN60T3) in the 109 o meridian (figure 5).

Good IOL alignment at the end of the procedure. Gentian violet mark is at approximately 105 degrees. Figure 5

Postoperative Course (OD) POD 1 Vsc 20/200 OD MR: x107 = 20/30 Toric IOL aligned at 47 o (45 o from intraoperative placement; figure 6) POD 7 Vsc 20/40 OD MR: x120 = 20/25+ Vision has been stable, patient very happy and desires no further intervention (ie: IOL rotation)

In image at left, the toric IOL is seen aligned at approximately 47 o With patient looking up and left (right image), the toric markings are easily seen. Figure 6

Discussion While the hydrophobic acrylic toric IOL (AcrySof R Toric IOL) has good documented rotational stability (1), significant rotation can occur. Evaluation of the surgical video demonstrates absence of deliberate viscoelastic removal from behind IOL optic. Subsequent to this case, we now deliberately remove viscoelastic from behind the toric IOL optic and have had no significant IOL rotations identified (60 subsequent toric IOLs implanted) It is estimated that each degree of rotation confers a 3.3% loss of effect, so that with a 30 degree rotation, the toric IOL has no effect (2). Inasmuch as a 90 degree IOL rotation confers a 100% induction of cylinder along the preoperative meridian, it can be expected that there is essentially no toric effect for rotations between 30 and 60 degrees. The 45 degree rotation identified in our case with a subsequent residual refractive astigmatism of 1.00D supports this theory. Objectively, the results in this case with a residual astigmatic refractive error of 1D fell short of our expectations. Subjectively, the patient tolerated the residual astigmatism well.

Conclusions While uncommon, hydrophobic acrylic IOLs can rotate significantly within the first 24 hours of surgery. Consider deliberately removing viscoelastic from behind the toric IOL optic to minimize rotational instability. For better or worse, a patient’s subjective assessment trumps objective findings in determining the patient’s level of happiness following eye surgery.

References Mendicute J, Irigoyen C, Aramberri J, Ondarra A, Monte´s-Mico´ R. Foldable toric intraocular lens for astigmatism correction in cataract patients. J Cataract Refract Surg 2008; 34:601–607 Novis C. Astigmatism and toric intraocular lenses. Curr Opin Ophthalmol 2000; 11:47–50