EyeWorld India March 2013 Issue

26 EWAP CATARACT/IOL March 2013 Haike GUO, MD, PhD Guangdong Provincial People’s Hospital Zhongshan 2 Road, Guangzhou, China Tel. no. +86-020-83844380 Fax no. +86-020-83844380 guohaike@medmail.com.cn C ontinuously developing IOL technologies allow surgeons to consider corneal astigmatism in planning the cataract postoperative refraction. In recent years, toric IOLs have proved effective in the correction of corneal astigmatism following cataract surgery. But toric rotation postoperatively has been found frequently, and it is a serious problem especially in high myopes. At the Guangdong Eye Institute, we usually use toric IOLs and capsular tension ring (CTR) implantation for the correction of corneal astigmatism in high myopia. In-the-bag IOL dislocation is thought to depend upon zonular instability, for example in eyes with traumatic injuries or pseudoexfoliation syndrome, after vitrectomy, in patients with Marfan syndrome, and in eyes with high myopia. The CTR has been found to provide stabilization of the capsular bag and IOL during and after cataract surgery in cases of zonular instability and large capsular bag. In our clinical observation, the use of toric IOLs and CTRs could provide rotational stability and IOL centration in large capsular bags because of the final refractive effect. As discussed, reverse optic capture (ROC) is another way of preventing toric rotation for high myopes. The optic capture was first described by Neuhann as rhexis-fixation lens in 1991 (a three-piece posterior chamber IOL was placed in the ciliary sulcus and then the optic was depressed posteriorly beneath the rim of the anterior continuous curvilinear capsulorhexis to achieve IOL stability). In contrast, ROC is achieved by capture of the optic anteriorly through the anterior capsulorhexis opening (haptics in the bag, optic anterior to rhexis). Now, it is often used in cases of incomplete or insufficient capsule support. Although ROC has been used for many other purposes and its technique is detailed, including the use of three-piece or one-piece IOLs, it has not been proved that ROC for toric fixtion in high myopia is stable and accurate through a precise clinical outcome. Prevention is more important than treatment for dealing with toric rotation. But for patients having toric rotation, waiting 4-6 weeks for capsular contraction and then performing the repositioning is a good way to solve the problem. In a word, I think toric IOL with CTR implantation is an effective method for correcting corneal astigmatism in the course of cataract surgery for patients with high myopia, and technical difficulties associated with it should not cause problems for an experienced surgeon. In addition, although creating individually adjusted IOLs is associated with the cost of the procedure, it is another way to solve the problem and may come true easily in the future. Editors’ note: Prof. Guo is a consultant for Alcon, but has no financial interests related to his comments. Views from Asia-Pacific Hadi PRAKOSO, MD Klinik Mata Nusantara Jl. Paus Dalam C-16, Rawamangun, Jakarta 13220 Indonesia Tel. no. +62-21-4700863 Hadi.eyesurgeon@gmail.com L ooking at Dr Safran’s cases, I would like to share my personal experience. I have had four post-op rotation cases (one was a high myope) out of my over 350 toric patients. All these cases occurred in the first week after surgery. When I reexamined the videos of those surgeries, I noticed that I had not removed the OVD meticulously from behind the IOL and the equator of the capsular bag. So, it is clear for me that residual OVD in the bag makes the bag so slippery that it prevents the IOL from staying in its proper position. When I repositioned my cases, I used cohesive OVD to release the capsular bag from its attachment to the IOL because it is easier to remove all OVD from the bag without leaving any residual OVD compared to using dispersive OVD such as Viscoat after repositioning is completed. All repositions were performed 2-5 weeks after the first surgery, and all IOLs remained stable after surgery in the desired position. I do not agree that leaving the LECs on the anterior capsule may facilitate adhesion of the IOL to the capsular back since all post-op rotation always occurs within the first post-op week before LECs undergo fibroblastic transformation. Also, I do not think that it is necessary to perform ROC when you restore the IOL position, because this is not an easy procedure on single-piece IOLs and on the other hand the potential risk of pigment dispersion and glaucoma may persist. A CTR with a 14-mm diameter in a large capsular bag as in high myopic eyes seems a rational way to avoid post-op rotation. The CTR will stretch the capsular bag and makes both the anterior and posterior capsule stay much closer to each other, which will clamp the haptics of the lens. Especially in a post-vitrectomy eye, the CTR will keep the capsular bag in its normal shape and secure the position of the IOL. Unfortunately, I do not have any experience with CTRs in such a case. Finally, I believe that the most important thing to prevent post-op rotation of a toric IOL is a thorough OVD wash from behind the IOL and equator of the capsular bag. Editors’ note: Dr. Prakoso has no financial interests related to his comments. dispersion due to interaction of the iris and one-piece AcrySof lenses a bit nervous, whether or not they have actual cause to be in this proposed situation. Dr. Horn (Vision for Life, Nashville, Tenn., USA) would take a more conventional approach. “Anecdotally, there does seem to be a higher incidence of rotation in long eyes with presumably large capsular bags,” he said. “In these cases, the lens has been reported to rotate again even after repositioning, and in at least some of these cases, the lens seems to rotate to the same position, implying that there is a ‘home’ in these particular eyes, which would suggest the bags are not round, but oval. So there may be place for a CTR, which would presumably ‘round out’ the capsular bag, reducing rotation if the lens were initially oriented in the long axis or diameter of the bag. Other things regarding surgical technique may be important to prevent rotation, continued on page 32 Taking - from page 25