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Vitreoretina Assessing Photoreceptor Structure in Macular Hole using Split-detector Adaptive Optics Scanning Light Ophthalmoscopy Edward L Randerson, 1 Drew Davis, 2 Brian Higgins, 3 Judy E Kim, 4 Dennis P Han, 4 Thomas B Connor, 5 William J Wirostko 5 and Joseph Carroll 4 1. Medical Student; 2. Ophthalmology Resident; 3. Research Technologist; 4. Professor of Ophthalmology; 5. Associate Professor of Ophthalmology, Medical College of Wisconsin, Department of Ophthalmology, Milwaukee, Wisconsin, US Abstract Introduction: Macular hole (MH) and vitreomacular traction (VMT) can involve disruption at the level of the photoreceptor interdigitation zone (IZ) and ellipsoid zone (EZ) with optical coherence tomography (OCT). Confocal adaptive optics scanning light ophthalmoscopy (AOSLO) has been used to examine the photoreceptor mosaic following surgical intervention in patients with MH and VMT, showing large ‘dark areas’ devoid of normal waveguiding cones. Using split-detector AOSLO, which allows visualisation of cone photoreceptor inner segments, we examined the macular cone structure in these disruptions. Methods: Seven eyes from six subjects with MH or VMT were imaged with spectral domain OCT (SD-OCT), confocal AOSLO and non-confocal split-detection AOSLO following pars plana vitrectomy (PPV) for MH or intravitreal injection with ocriplasmin for VMT. Results: Split-detector AOSLO imagery revealed remnant inner segment structure within dark areas observed with confocal AOSLO. In addition, split-detector images demonstrated that not all hyperreflective dots in confocal AOSLO images were derived from cones. Conclusion: Split-detector AOSLO provides additional information for these retinal conditions, and is likely to become an invaluable tool for assessing residual cone structure in conditions where disrupted cone structure interferes with the ability to visualise cells with confocal AOSLO. Keywords Adaptive optics, macular hole, vitreomacular traction, optical coherence tomography, photoreceptor, inner segment Disclosure: Edward L Randerson, Drew Davis, Brian Higgins, Judy E Kim, Dennis P Han, Thomas B Connor, William J Wirostko and Joseph Carroll have no conflicts of interest to declare. No funding was received in the publication of this article. The authors wish to thank Kainat Akhter, Rob Cooper, Mara Goldberg, Moataz Razeen, Chris Skumatz, Melissa Wilk and Jon Young for assistance with retinal imaging. Open Access: This article is published under the Creative Commons Attribution Noncommercial License, which permits any non-commercial use, distribution, adaptation and reproduction provided the original author(s) and source are given appropriate credit. Compliance with Ethics Guidelines: All procedures were followed in accordance with the responsible committee on human experimentation and with the Helsinki Declaration of 1975 and subsequent revisions. Informed consent was received from the all patients involved in the study. Received: 5 May 2015 Accepted: 30 June 2015 Citation: European Ophthalmic Review, 2015;9(1):59–63 Correspondence: Joseph Carroll, The Eye Institute, 925 N 87th St Milwaukee, WI, US. E: Support: Supported by National Institutes of Health (NIH) grant P30EY001931, Thomas M Aaberg, Sr, Retina Research Fund, Foundation Fighting Blindness, RD and Linda Peters Foundation and an unrestricted departmental grant from Research to Prevent Blindness, Inc., New York, NY. This investigation was conducted in a facility constructed with support from the Research Facilities Improvement Program, Grant Number C06RR016511, from the National Center for Research Resources, National Institutes of Health. The sponsors or funding organisations had no role in the design or conduct of this research. Macular hole (MH) and vitreomacular traction (VMT) can result in disruption of the vital area of contact between the photoreceptors and the nourishing retinal pigment epithelium (RPE). 1–3 Optical coherence tomography (OCT) has become the gold standard tool for diagnosing and managing these conditions. 3–5 OCT is often used for monitoring surgical outcomes in patients with MH and VMT, to ensure that the hole has closed or VMT has released. However, in some patients, despite achieving the desired anatomical outcome, disruptions are seen at the level of the photoreceptor bands on OCT (EZ and IZ). In other patients, despite less-than-expected visual improvement, no abnormality is seen on OCT. In fact, there are inconsistencies across studies comparing OCT findings to visual acuity. 5–13 While the integrity of the photoreceptors is of greatest interest in both, the limited lateral resolution of OCT precludes quantitative assessment of photoreceptors by enumeration and cellular integrity. Given that photoreceptor structure may hold prognostic value for patients with MH and VMT after surgical intervention, there Tou ch MEd ica l MEdia is a requirement to develop advanced imaging approaches in these patients. Adaptive optics scanning light ophthalmoscopy (AOSLO) is capable of correcting the eye’s monochromatic aberrations, enabling in vivo imaging of the photoreceptor mosaic with cellular resolution. 14,15 AOSLO has been used to image patients with EZ/IZ abnormalities due to ocular trauma, 16 following surgical closure of idiopathic MH 17–19 and eyes with epiretinal membrane (ERM). 20 A general finding in previous patients was the consistent presence of ‘dark areas’ within the central macula; previously, it had been suggested that these areas were due to cone cell loss. 17,19 However, conventional confocal AOSLO suffers from a significant limitation – detection of photoreceptor cells relies on proper waveguiding of light by structurally intact cells. 21 Thus, loss of the reflective signal on confocal AOSLO in these patients may be due to damaged as opposed to absent cone cells. Resolving this matter is critical to realising the full potential of advanced imaging for evaluating surgical outcomes and establishing realistic expectations 59