Eyeworld

143 EW INTERNATIONAL March 2018 CBDS lacked these features and was generally not recognized until visual acuity was compromised. All CBDS types are associated with contact or adherence between the IOL and the anterior leaf of the posterior capsule that leads to fluid accumulation and subsequent bag swelling. Correctly identifying the type of CBDS is important to understand the nature and effective treatment of this disorder. According to a study presented at the XXXV Congress of the ESCRS, CBDS may best be subdivided into types 1–4, based on the transparent/opaque nature of the capsular bag and in- tracapsular fluid. "Despite the many names that this entity has been giv- en, such as capsular block syndrome, capsular bag hyperdistension, and capsulorhexis block syndrome, and the various ways it has been classi- fied by different researchers, the four types of CBDS that we identified and present in this study may be consid- ered as different stages of the same process," said Anna Vlasenko, MD, S. Fyodorov Eye Microsurgery Feder- al State Institution, Moscow, Russia, who presented the study. The study included 17 eyes of 16 patients (10 men, six women) with CBDS in the late postoperative period, after uneventful cataract sur- gery with phacoemulsification and in-the-bag IOL implantation. Cata- ract surgery was carried out between 2 and 11 years (mean 4.9 ± 2.8 years) prior to CBDS symptoms emerging. The mean patient age was 66.9 ± 11.9 years (range: 44–88 years). The mean axial length in the patient group was 24.7 ± 1.7 mm (range 22.49–28.44 mm). Among the implanted IOLs were mostly sin- gle-piece hydrophobic acrylic IOLs and one hydrophilic IOL; 13 eyes had different AcrySof IOL models (Alcon, Fort Worth, Texas), three eyes had Hoya IOLs (Hoya Surgical Optics, Singapore), and one eye had a Hanita IOL (Hanita Lenses, Israel). The retro-optical content characteristics included posterior capsule opacification (PCO) and connections between the capsular bag periphery and the retro-optical space. Dr. Vlasenko implemented slit lamp biomicroscopy and optical coherence tomography (OCT) to evaluate capsular bag content, PCO, and connections between the bag and periphery with the retro-optical space. Dr. Vlasenko classified four of the patients in her study as type 1 CBDS. These eyes presented with a transparent capsule and transpar- ent liquid inside the capsular bag, which was barely noticeable via slit lamp biomicroscopy, but clearly seen using anterior segment OCT. Dr. Vlasenko suggested that eyes demonstrating transparent retro-op- tical contents and a transparent posterior capsule be classified as type 1 according to this new classifica- tion system, and managed through follow-up. Two cases involved homoge- neous milky fluid in the capsular bag and a transparent posterior capsule. These clinical characteristics repre- sented the next stage in the progres- sion of CBDS, classifying it as type 2 CBDS. In one of these cases, the patient, a 76-year-old male patient who was 6 years postop, complained of blurred vision. Posterior cap- sule puncture using YAG laser was performed, releasing the trapped, dense liquid into the vitreous, and restoring visual acuity with no fur- ther complications. The second case involved a 46-year-old male patient who was 5 years postop and had no visual complaints. His visual exam showed a slightly more myopic visu- al acuity, and Dr. Vlasenko decided to wait and follow the patient. The CBDS resolved spontaneously in 6 months. Six cases were classified with type 3 CBDS, presenting with trans- parent or semitransparent liquid accumulation and PCO, indicating a further step in the progression of symptoms. In five of the cases with PCO, the capsular bag content was turbid. YAG laser posterior capsulo- tomy was performed, releasing the capsular bag contents into the vitre- ous cavity, which was then followed by posterior capsulotomy. Type 4 CBDS (opaque contents and PCO) was noted in 5 cases, among them a 44-year-old male patient who underwent surgery 11 years prior. Opaque contents were observed in the capsular bag and excessive lens epithelial cell (LEC) proliferation was visualized at the periphery of the capsular bag (Soemmering's ring), and some LECs were coming out of the capsular bag into the anterior chamber. Since the patient had episodes of eye redness, surgical aspiration was planned in that case. Dr. Vlasenko explained that patients with type 4 CBDS will often benefit from YAG laser capsu- lotomy, which was performed in the other four cases. "We know that the capsular bag usually wraps the IOL (capsular fusion) within the first few weeks postoperatively," Dr. Vlasenko said. "Via slit lamp biomicrosco- py and OCT scan, we can see that the anterior and posterior capsule leaves are closely attached to the IOL. Nevertheless, the exact reason for capsular bag distension is not clear. We think that the mechanism is similar to PCO formation, caused by proliferation and migration of residual LECs that remain in the equator of the capsular bag. It is also known that the optic haptic junc- tion is a point of weakness in the barrier effect of the square edge IOL design that provides migrating LECs access to the posterior capsule. 3 LEC migration as well as products of its lysis passing into the retro-optical space behind the optic haptic junc- tion area are presumably one of the major mechanisms leading to CBDS formation. However, the exact caus- es of CBDS are yet to be discovered. In any event, we consider the types of CBDS presented here as different stages of the same process." EW References 1. Kim HK, et al. Capsular block syndrome after cataract surgery: clinical analysis and classification. J Cataract Refract Surg. 2008;34:357–63. 2. Miyake K, et al. New classification of cap- sular block syndrome. J Cataract Refractive Surg. 1998;24:1230–4. 3. Nixon DR, et al. Evaluation of lens epithelial cell migration in vivo at the haptic-optic junction of a one-piece hydrophobic acrylic intraocular lens. Am J Ophthalmol. 2006;142:557–62. Editors' note: Dr. Vlasenko has no financial interests related to her comments. Contact information Vlasenko: annavlasenko@mail.ru " Despite the many names that this entity has been given … and the various ways it has been classified by different researchers, the four types of CBDS that we identified and present in this study may be considered as different stages of the same process. " —Anna Vlasenko, MD

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