Eyeworld

EW NEWS & OPINION September 2015 25 by Steven G. Safran, MD What bugs Bunnie? "B unnie" is a 66-year-old woman referred by an optometrist who has cared for her for decades. He is a superb contact lens specialist and under his supervision she had worn gas permeable contact lenses for moderate keratoconus successfully until about one year ago when she had cataract surgery in both eyes with placement of toric intraocular lenses. Since then Bunnie has been extremely unhappy with her vision and unable to wear contact lenses. She has been referred to me for consideration of lens exchange in both eyes to allow her to wear contact lenses again. At her evaluation in my office she brings no glasses with her, and her vision is 20/50 or so uncorrected OU. Her refraction is between +1.25 and +1.5 in her dominant OD for 20/20-2, and in the left eye her refraction is consistently +1.5-2.0 x 115 for 20/25+ best corrected. She insists she does not want to wear glasses under any circumstances for distance. She never wore them before and will not consider wearing them now, although she does not mind wearing them for reading if necessary. She is very insistent that a solution to her problem must provide good distance vision in both eyes without glasses correction. When I discuss the option of removing the toric IOLs and going back to gas permeable contact lens wear as a potential option she said, "I paid extra for these toric intraocular lenses, and if I could see like I'm supposed to with them, that's what I want. I don't want to go back to contact lenses. I want these lenses I paid for to work for me like they should." When I review her records provided by the original cataract surgeon, the plan in the OD was for an SN6AT7 7.0 D lens (Alcon, Fort Worth, Texas) placed at 100 degrees, and it's sitting pretty close to plan at 103 degrees. She has no refractive cylinder in this eye but does have a +1.25 to +1.5 hyperopic outcome. Her OS surgical plan was for an SN6AT7 11.5 D lens at 84 degrees, but it's sitting at 93 or 94 degrees instead, and she refracts consistently to +1.5-2.0 x 115. When I trial frame her with her correct refraction on 2 separate occasions, she insists that she would be happy if she could see like this without glasses. She has been out of contact lenses now for more than a year and her corneal topog- raphy is consistent with moderate keratoconus demonstrating inferior hemi-meridional steepening and minimal skew deviation in both eyes. What do I do with this patient? What are the options? What would you do and on which eye would you do it first? I asked these questions of Eric Donnenfeld, MD, Rockville Centre, N.Y., Yuri McKee, MD, Mesa, Ariz., George Beiko, FRCSC, St. Catharines, Canada, and Warren Hill, MD, Mesa, Ariz., to get their thoughts on how they would manage this patient. Steven G. Safran, MD, ASGR editor Anterior segment grand rounds (ASGR) Figures 1 and 2: Topography from OD and OS Management of a keratoconus patient unhappy with her outcome after bilateral toric IOL cataract surgery D r. Donnenfeld said: "The first lesson to be learned in this case is that patients who are happy gas perme- able contact lens wearers should be treated with caution when it comes to toric IOLs. Once the toric IOL is placed, the cylinder in the eye cannot be corrected with a rigid contact lens. In this case the cylinder is fairly regular so the patient was a good candidate for a toric IOL, but the informed consent should be extensive. In patients with more irregular corneas, toric IOLs are often not a good option. "For this patient the residual refractive error is the main concern and not quality of vision. In the right eye the patient has a hyperopic refractive error of +1.50. There are 3 reasonable alternatives for resolv- ing this problem. The IOL could be exchanged for a lens that had the same cylinder correction but was of higher power. For hyperopic correc- tions that are less than 5 D, I simply multiply the residual refractive error by a factor of 1.5, which in this case would result in a difference of 2.25 D. The patient now has a 7 D T7 IOL. I would exchange it with continued on page 26 a 9.5 D T7 IOL. Option 2 would be to place a 2.5 D piggyback IOL. I prefer the STAAR Surgical 2010AQ (Monrovia, Calif.) or the Bausch + Lomb SofPort AO (Bridgewater, N.J.). Finally, I would consider a PRK but would want to perform riboflavin UV crosslinking first. In this case I would opt for the piggyback IOL as the patient would like to keep her current IOL in place, and it is a less invasive procedure. "For the second eye there is mostly cylinder but also a little residual hyperopia with a residual spherical equivalent of +0.50 D. The simplest technique would be to go to the website www.astigmatismfix. com and calculate the correct axis for this lens and rotate the lens accordingly. I would inform the patient that a piggyback IOL or PRK might still be required at a later date."

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