EyeWorld Asia-Pacific December 2016 Issue

December 2016 14 EWAP FEATURE Views from Asia-Pacific Kenneth FONG, FRCOphth FRANZCO Honorary Secretary, Malaysian Society of Ophthalmology Consultant Ophthalmologist and Vitreoretinal Surgeon Sunway Medical Centre and Beacon Hospital, Petaling Jaya, Malaysia kcsfong@gmail.com eyeretina.my T here are several factors to consider when operating on a cataract in an eye which has had a previous vitrectomy. 1. Previous retinal pathology, which may limit the visual improvement after cataract surgery. For example, an eye with a macula off retinal detachment that has been anatomically repaired may never achieve 20/20 visual acuity no matter how perfect your cataract surgery is. Additionally, patients may notice more distortion of vision after their cataracts have been removed and should be warned about this. This is usually seen in superior macula off rhegmatogenous retinal detachments when there may be very fine retinal folds over the macula that may not be very obvious due to the cataract obscuring the view of the retina. 2. These cataracts are technically very challenging and should not be left for junior surgeons to operate on unsupervised. The cataracts are usually dense, have small pupils prone to reverse pupillary block, very deep anterior chambers, and fibrotic lens capsules. I avoid topical anesthesia in such cases as the iris–zonular complex is very mobile and patients often complain of discomfort during phacoemulsification. There is a higher possibility of posterior capsule rupture due to previous lens touch during the previous vitrectomy surgery. 3. IOL power calculation may be inaccurate. There is a possibility of getting a hypermetropic surprise and this is usually due to the IOL–bag complex being located further posteriorly than planned due to the lack of vitreous support. On the other hand, some studies have reported myopic surprise in combined phaco and vitrectomy cases, and this was attributed to the gas tamponade pushing the IOL forward. I avoid using multifocal IOLs in patients with previous vitrectomy due to the postop refractive unpredictability. Patients have to be warned that they may still need glasses after surgery. 4. In eyes that have had silicone oil inserted and removed, warn the patient that they require long-term follow up for glaucoma and corneal endothelial cell loss. Combined cataract surgery and silicone oil removal should only be done by vitreoretinal surgeons. I would not recommend doing cataract surgery alone and leaving the silicone oil behind as the oil always migrates forward during and after cataract surgery and this causes many problems. Surgical tips 1. Have capsule tension rings, iris retractors or pupil dilating devices ready even if the pupil appears to be well dilated before surgery. It is quite amazing how much the pupil size can vary during such cases and early use of iris retractors can prevent posterior capsule rupture from occurring. Zonular weakness should be anticipated as well. 2. Use reduced infusion pressure or lower bottle height during phacoemulsification to prevent over deepening of the anterior chamber and reverse pupil block. 3. If a posterior capsule plaque is visible, this means that the posterior capsule is prone to rupture. I avoid hydrodissection and manage the case like a polar cataract. 4. Corneal wound leak is more likely in such vitrectomized eyes that are often also myopic. I always suture the main corneal wound at the end to prevent endophthalmitis. 5. Postoperatively, I anticipate more prolonged inflammation and I ask my patients to use topical steroid drops for at least 6 weeks after surgery compared with 3 weeks for routine cataract cases. Editors’ note: Dr. Fong declared no relevant financial interests. YAO Ke, MD Professor, Eye Insitute of Zhejiang University Eye Center, Second Affiliated Hospital of Zhejiang University, College of Medicine, China 88 Jiefang Road, Hangzhou, 310009, China Tel. no. +86-571-87783897 Fax no. +86-571-87783897 xlren@zju.edu.cn V ery meaningful topic. With the improvement of vitrectomy techniques and the relaxation of surgical indications, cataracts in the post-vitrectomized eye also increase. As the anatomy and physiology of the eye has changed after vitrectomy, cataract surgery in these cases also faces the corresponding difficulties and challenges. Although the operation goes smoothly in most cases, some notes such as those mentioned in the article still have important guiding significance in individual cases. I fully agree with the reminder about the occurrence time of cataract. Cataracts that rapidly develop after pars plana vitrectomy or intravitreal injection indicate an iatrogenic break of the posterior capsule. Early attention and preparation may reduce the risk of the lens nucleus falling into the vitreous cavity. Here, I would like to make some suggestions. First, femtosecond laser(FSL)-assisted phacoemulsification can be used in the post- vitrectomized eye. During the surgery, a predictably sized and centered anterior capsulotomy is performed, and avoids stresses on the zonules during capsulorhexis. We also use FSL to perform a central liquefaction with the grid pattern in soft lenses and a 6-pieces prefragmentation in hard ones. This reduces the ultrasonic phacoemulsification power and time. Second, for those cases with dense nuclear and zonular instability, when the anterior chamber is especially deep, it is difficult to perform intracapsular surgery. After hydrodissection, I prefer to catch the nucleus out of the capsule by means of the ultrasonic emulsifying needle, and chop it in front of the bag, so as to avoid tension to the zonules. Finally, for patients who have undergone more than one vitrectomy, or when the nucleus is very hard, there is a potential risk of changing the surgical approach to extracapsular cataract extraction (ECCE). The use of intravitreal liquid perfusion will ensure intraoperative intraocular pressure control, thus avoiding scleral collapse, massive suprachoroidal hemorrhage, and other serious complications. Editors’ note: Prof. Yao declared no relevant financial interests. Achieving - from page 13