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By
Stefanie Petrou-Binder MD
She and her team at the University Clinic for Ophthalmology and Optometry, Vienna, Austria implanted individually crafted toric silicone IOLs (MicroSil 6116 TU, Schmidt) in 14 eyes of nine patients. Four of the patients had previously undergone keratoplasty. “The implantation of toric IOLs to reduce pre-existing corneal astigmatism may improve visual acuity after cataract surgery. But the correction of high corneal astigmatism, for example after keratoplasty, was limited until now,” she said. The MicroSil 6116 lens is a three piece foldable silicon IOL with z-haptics. The diagonal length is 11.6 mm and the optical diameter 6.0 mm. The cataract surgery was standard in all cases. Eleven of the patients had a sclerocorneal incision, and the remaining three had a clear corneal incision. The surgeon implanted the toric IOL through the 3.2 mm incision with a pair of tweezers recommended by the manufacturer, or alternately with a micro-injector. While the insertion of the lens with tweezers required more experienced surgical skill, IOL injection using a micro-injector was more easily reproducible. The investigators evaluated visual acuity with and without the best spherical and the best corrected visual acuity at one week, and one, three, six, and 12 months postoperatively. They also measured the refraction, corneal astigmatism and postoperative rotation of the IOL. All patients had a minimal follow-up of six months. Dr Dejaco-Ruhswurm calculated the cylindrical power of the lens individually for each patient, depending on the degree of keratometric astigmatism. Schmidt, which produces the lens, manufactures lenses with cylindrical power of up to 12 D. The mean preoperative keratometric astigmatism was 5.28 D (± 3.53 D) and the mean preoperative refractive astigmatism 3.73 D (± 1.52 D). Four of the patients underwent PK. The mean cylindrical power of the implanted IOLs was 5.50 D (± 2.74 D.) The refractive astigmatism was reduced to +0.68 D (± 0.75 D) following surgery. The mean amount of postoperative keratometric astigmatism was +4.62 D (± 3.32 D). Visual acuity without correction was 0.55. With spherical correction, it registered 0.7 and BCVA acuity was 0.8. The researchers observed no significant IOL rotation in nine patients followed for six months or more. At the XX ESCRS Congress in Nice in September last year, Dr Sven Kulus and colleagues from the Klinik Dardenne in Germany reported that the MS 6116 performed well in six eyes with high astigmatism following keratoplasty. Post-PK keratoplasty astigmatism was reduced from a mean of 7.5 D to 2.4 D following IOL implantation.
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