Eyeworld

JUNE 2022 | EYEWORLD | 59 C by Liz Hillman Editorial Co-Director About the physicians Kevin M. Miller, MD Kolokotrones Chair in Ophthalmology David Geffen School of Medicine University of California, Los Angeles Los Angeles, California Abhay Vasavada, MD Director Raghudeep Eye Clinic Ahmedabad, India Ronald Yeoh, MD Medical Director Eye & Retina Surgeons Singapore References 1. Pujari A, Sharma N. The emerg- ing role of anterior segment optical coherence tomography in cataract surgery: current role and future perspectives. Clin Ophthalmol. 2021;15:389–401. 2. Wang X, et al. OCT applica- tion before and after cataract surgery. OCT Applications in Ophthalmology. 2018. 3. Asam JS, et al. Chapter 13: An- terior segment OCT. High Reso- lution Imaging in Microscopy and Ophthalmology: New Frontiers in Biomedical Optics. 2019. Relevant disclosures Miller: None Vasavada: Alcon Yeoh: Alcon, Carl Zeiss Meditec, Johnson & Johnson Vision cataracts," he said. "It can also be used to define the shallowness of an anterior chamber or docu- ment the presence of iridocorneal adhesions." Dr. Miller said that he's selective as to when he'll use AS-OCT preoperatively. He'll only use it preop if a posterior polar cataract is present. In- traoperatively, he'll use it as part of the process of performing FLACS. Postop, Dr. Miller listed five possible appli- cations for AS-OCT: 1. Look for/document the presence of retained lens fragments in the anterior chamber 2. Identify Descemet's membrane detachments in eyes with edematous corneas 3. Document the presence of capsular block 4. Look for epithelial or fibrous ingrowth 5. Look for IOL tilt and/or decentration He added that he finds identifying Descem- et's membrane detachments to be especially helpful when he can't figure out why it is taking so long for an eye to recover from surgery. Abhay Vasavada, MD, said he relies on anterior segment OCT frequently, finding it useful in cases of chronic angle closure glauco- ma, pseudoexfoliation, eyes with zonulopathy, posterior polar cataract, and pediatric cataract (if the child can sit for it). "I think the modern technology of the anterior segment OCT is helping in different scenarios where cataract surgery is done. With a shallow anterior chamber, for example, in many of these there are loose zonules, which can lead to the forward movement of the zonular-cap- sular bag. If you can see on anterior segment OCT, you are prepared for your strategy be- cause sometimes, even if you do in-the-bag IOL implantation, because the zonules are weak or loose, the IOL remains forward, and sometimes that shallowing of the chamber can lead to so- called angle glaucoma," Dr. Vasavada said. In eyes with known chronic angle closure glaucoma, he said anterior segment OCT can show and validate the change—space created and ciliary body rotation—from preop to post- op. "You can see the restoration to some extent of the anterior segment anatomy," Dr. Vasavada said. T he application of anterior segment OCT (AS-OCT) in cataract surgery is relatively new. 1 The authors of a 2021 review of AS-OCT described the current role of the technology and perspectives and its potential future application, concluding: ASOCT technology is comprehensively making progress in the assessment of cataractous eyes in the preoperative as well as intraoperative periods. The positive role of ASOCT in objectifying the cataractous grade, intralenticular changes in white/mature cataracts, and posterior capsular changes in posterior polar and traumatic cata- racts cases demonstrates its definite adjuvant role in routine clinical practice. In addition, compared to previous technologies, emerging swept source technology has furthered the cross-sectional imaging as a more practical tool. Hence, ASOCT is likely to become an integral part of assessment when dealing with complex lenticular entities in future. The authors of a chapter in the book OCT Applications in Ophthalmology described the various ways in which they saw value of the technology for cataract surgery, including "(1) anterior lens capsule and lens epithelium evalu- ation using spectral-domain OCT (SD-OCT); (2) investigation of clear corneal incision in fem- tosecond laser assisted cataract surgery using SD-OCT; (3) capsular block syndrome evalua- tion before and after treatment using SD-OCT; [and] (4) IOL power calculation in post-myopic excimer laser eyes using SD-OCT." 2 A book chapter in High Resolution Imaging in Microscopy and Ophthalmology: New Fron- tiers in Biomedical Optics described the various technologies with anterior segment OCT capa- bilities. 3 While many applications are related to cornea (which can have implications on refractive cataract surgery), some technologies have increasing applications that can aid in IOL calculations, the authors wrote. Preop and postop applications Kevin M. Miller, MD, said preoperative and post- operative imaging with AS-OCT can be helpful. "Preoperatively, anterior segment OCT can be used to identify posterior capsule openings or posterior lenticonus in eyes with posterior polar Anterior segment OCT for cataract surgery: preop, intraop, and postop applications continued on page 60

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