EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/78788
August 2012 For patients with visually signif- icant cataracts but with mild guttae and minimal stromal corneal edema on exam, it's reasonable to proceed with cataract surgery alone, with special attention given to surgical technique as described below so as to minimize traumatic injury to the already diseased corneal endothe- lium. Surgical technique Viscoelastic selection: Protection of the corneal endothelium is of para- mount importance in patients with mild Fuchs' dystrophy undergoing cataract surgery. One important way to minimize endothelial trauma is to use a dispersive viscoelastic (e.g., Viscoat, Alcon, Fort Worth, Texas, or Healon D, Abbott Medical Optics, Santa Ana, Calif.) during pha- coemulsification. With shorter side chains and lower viscosity, such vis- coelastics easily disperse throughout the anterior chamber after injection, providing a true protective coating to the corneal endothelium that lasts longer than cohesive viscoelas- tics during the operative procedure. This protective coating serves as a mechanical barrier to excessive ul- trasound energy and trauma during phacoemulsification that may other- wise harm the corneal endothelium. Special attention should also be given to removing dispersive vis- coelastics from the anterior chamber after phacoemulsification. For the same reasons that they provide a protective coating to the endothe- lium, these viscoelastics tend to ad- here to the endothelium, and if thorough aspiration and irrigation of the anterior chamber is not per- formed, the patient may be at in- creased risk of a post-op rise in IOP related to retained viscoelastic obstructing aqueous outflow. Phaco technique and technol- ogy: Specific phacoemulsification techniques may also play a role in the amount of energy produced and resultant trauma to the corneal en- dothelium. In general, we recom- mend using a phaco-chop technique rather than a divide and conquer technique. In our experience, this technique allows for less phaco power and phaco time necessary for cataract extraction. Wong et al per- formed a prospective, randomized study comparing phaco time and phaco power between the two tech- niques and found similar results.1 In addition, we recommend using advanced phacoemulsification technologies (i.e., torsional or trans- versal ultrasound), which offer the benefits of increased efficiency in lens removal, greatly reduced repul- sion of lens material from the tip, decreased turbulence in the anterior chamber, enhanced followability of lens material, and less risk of ther- mal corneal wound burns. We have previously published results showing overall less cumula- tive dissipated energy and less en- dothelial cell loss when a torsional handpiece was used through a 2.2 mm micro-incision compared to a 2.8 mm standard technique.2 Post-op considerations A patient with mild Fuchs' corneal dystrophy who has undergone cataract surgery alone should be fol- lowed carefully in the post-op period to ensure clearing of any surgery-re- lated corneal edema. These patients benefit from more frequent steroid use or use of a more potent steroid (i.e., difluprednate 0.05%). In addi- tion, we occasionally give these pa- tients topical hyperosmotic agents (e.g., sodium chloride hypertonicity ophthalmic solution 5% and oint- ment) in the early post-op period to expedite and ensure deturgescence of the cornea. Conclusions In summary, while DSAEK surgery provides safe and predictable out- comes for patients with Fuchs' dys- trophy, there are certain clinical scenarios where we may consider cataract surgery alone in a patient with mild Fuchs' dystrophy. When we do proceed with cataract surgery in such patients, we plan our surgi- cal technique and utilize advanced phacoemulsification technologies in order to minimize corneal endothe- lial trauma and maximize endothe- lial protection so that the best visual outcomes can be offered to our patients. EW References 1. Wong T, Hingorani M, Lee V. Phacoemulsifi- cation time and power requirements in phaco continued on page 30