EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/78788
August 2012 Refractive challenges and innovations February 2011 A toric challenge: Surgeons review a complicated case by Jena Passut EyeWorld Editor F rom selection to insertion, toric lenses may present challenges to the best of surgeons. EyeWorld pre- sented a complicated toric case from Kerry D. Solomon, M.D., EyeWorld refractive editor, and director, Carolina Eyecare Research Institute, Carolina Eyecare Physi- cians, Charleston, S.C., and asked surgeons to comment on how they would handle it. A 77-year-old man complained of worsening vision, trouble with glare and haloes, and difficulty driv- ing at night after having toric lenses implanted. Pre-op, his manifest re- fraction (MRx) was –0.50 +0.50 x 15 in the right eye and –2.00 +2.00 x 165 in the left. Slit lamp evaluation on both eyes was given a score of 2+ with nuclear sclerotic and cortical changes. Corneal topography, corneal measurements, and surgical plan for the left eye are shown (Figures 1 and 2). Three weeks post-op, the patient complained that he would like his visual acuity (UCVA: 20/40; MRx: –0.75 +1.25 x 180; toric IOL@144 degrees) to be better. "This case artfully illustrates some of the commonly occurring challenges facing the refractive cataract surgeon today, despite the availability of an impressive suite of new technologies aimed at offering extreme precision," said Neel R. Desai, M.D., Largo, Fla. "These challenges snowball from the pre-operative biometry and IOL selection onward to intraoperative alignment of the toric IOL and ulti- mately manifest in a curious post- operative refractive surprise." Dr. Desai and John P. Berdahl, M.D., Sioux Falls, S.D., shared their thoughts. After looking over the case, what would you do next? Dr. Desai: To begin, the biometry is rather inconsistent and misleading with regard to the true magnitude and axis of astigmatism. The avail- able topography, in this particular case, reveals considerable asymmetry and irregularity that often corre- sponds to pre-existing ocular surface disease, such as Salzmann's nodular degeneration. Other cases of seem- ingly irregular astigmatism may be a result of dry eye syndrome, eccentric scans, prolonged (rigid) contact lens wear, or more easily identified kera- toectatic disorders. Radial kerato- tomy may also generate irregular patterns of astigmatism that are difficult to compensate for with conventional techniques like LRI or toric IOLs. When presented with similar challenging cases of mislead- ing pre-operative biometry, I am fre- quently saved by the availability of the WaveTec ORA (WaveTec Vision, Aliso Viejo, Calif.) intraoperative wavefront aberrometry. The real- time aphakic and pseudophakic refractive data provided can allow intraoperative optimization of IOL power selection and alignment that takes into account the patient's cen- tral visual axis, angle kappa, and sur- AT A GLANCE • Asymmetry and irregularity on topography could point to pre- existing ocular surface disease • Consider laser vision correction enhancements gically induced astigmatism (SIA). In this case, the ORA may have led us to select a T5 Toric (Alcon, Fort Worth, Texas), with 3.0 D of correc- tion in the IOL plane and 2.06 D of correction in the spectacle plane, from our consignment of toric IOLs. Furthermore, the ORA system may have helped fine-tune IOL orienta- continued on page 44 EW FEATURE 43 Figure 1 Figure 2 Source: Kerry Solomon, M.D.