Eyeworld

MAY 2012

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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December 2011 EW NEWS & OPINION 17 Figures 3-6. The patient's OCT of the optic nerve showed some superionasal thinning of the NFL, but her OS was normal completed first (if she is willing) and would tend to recommend a target of –1.0 to aid her mid-range using an aspheric IOL, although I could not fault use of a Crystalens with mini monovision of perhaps –0.50." Dr. Horn commented, "I likely would implant a monofocal lens in this eye. If the patient wanted a presbyopic-correcting IOL, I would use the Crystalens AO; however, if the patient was very keen on uncorrected near I would consider a multifocal lens." My thinking was very much in line with that of the panel. I decided to do cataract surgery in the left eye first to get this patient functional as I felt poor vision in the dominant left eye and anisometropia were her biggest problems and the easiest ones to fix. I chose the Crystalens AO with a –0.25 target. She ended up plano in this eye and absolutely thrilled with the quality of her distance and intermediate vision. She also maintained a normal IOP without the need for glaucoma medication. Now the question was what to do with the right eye. Dr. Whitman commented, "I would try a contact lens trial to leave her at +0.25 sphere (will help with the intermediate VA), and if she deals with it relatively well—it does not have to be a home run— then I would do LVC shooting for plano. If not, consider vitrectomy and possible suture fixation of the IOL … The only reason to do the vitrectomy is to help with the visual quality as I have removed vitreous in front of a multifocal optic and the patient noticed substantial improve- ment." Dr. Horn felt that the Kruken- berg spindle and the nerve fiber layer thinning may be additional factors. "I think the choice of a multifocal for the right eye may not have been best. I say this because of the NFL thinning combined with PDS. This may reduce contrast sensi- tivity too much because of pre-exist- ing contrast loss. I also think dense Krukenberg spindles may potentially result in diminished contrast when combined with a multifocal lens." Dr. Myers commented, "It seems Figure 7. A post-op image of the patient's eye Source (all): Steven G. Safran, M.D. that her symptoms are in part from two causes. One is the power mis- match between the intended refrac- tive target and her current hyperopic status. That could be addressed later with PRK. The second issue is the ap- parent translocation of the lens asso- ciated with vitreous in the anterior chamber and zonular deficit only partially managed with a CTR. I think the wavefront would show considerable coma due to the displacement, and that could also possibly induce some hyperopia. "I would plan to take her to surgery to try to reposition the IOL more centrally along with an ante- rior vitrectomy with triamcinolone visualization." So now we have a list of possible reasons for the patient being un- happy with the quality of vision in her right eye. The presence of a Krukenberg spindle and her nerve fiber layer deficit are felt to be possi- ble problems, especially in the pres- ence of a multifocal implant, but these are things that are not "fix- able" except by exchanging the im- plant to make them less of an issue. The vitreous strands crossing the im- plant, the slightly tilted optic, and her refractive error are also consid- ered problematic by members of the panel, and these are more amenable to surgical repair without resorting to implant exchange. Treatment My plan here was to remove the vit- reous strands with a triamcinolone- assisted pars plana vitrectomy combined with lassoing of the CTR in the area of maximum zonular weakness at around 4:00. The scleral fixation of the CTR in this region would hopefully bring this complex more anterior and thus eliminate the slight tilt of the optic, the possi- ble coma effect mentioned by Dr. Myers, but also might make her effective lens position a bit more an- terior and possibly reduce her hyper- opic outcome. I felt that if I could reduce her hyperopia by half, this would probably give her an accept- able compromise of improved uncorrected distance vision with a near point that would blend well with her left eye, which was now plano with a Crystalens. Figure 7 shows the post-op image of the eye. Note that the im- plant has been brought further for- ward, and the patient's uncorrected acuity improved to 20/25-2. Her re- fraction ended up right around +0.5, and this did indeed give her a near point that she could live with and acceptable distance vision in this, her non-dominant eye. Her quality of vision did improve subjectively as well, suggesting that perhaps the lens tilt or vitreous strands crossing the pupil were playing a role in di- minished quality of vision. I did dis- cuss "tweaking" her outcome with PRK to get her closer to plano, but the patient decided that she was happy with the outcome. I felt that this was an interesting case because of the surgical manipu- lation of effective lens position to "tweak" the refractive outcome of her previously performed cataract surgery. Achieving an excellent out- continued on page 19

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