The Impact of Lens Vault on Visual Acuity and Refractive Error: Implications for Management of Primary Angle-closure Glaucoma Monisha E. Nongpiur, MD,*w Shweta Singhal, PhD,* Stephen Stewart, MA, MBBS,z Hla M. Htoon, PhD,*w Arun K. Narayanaswamy, DO, DNB, MMED,*w Tien Y. Wong, FRCS, PhD,*wy Shamira A. Perera, BSc (Hons), FRCOphth,* and Tin Aung, FRCS, PhD*wy Purpose: To investigate the relationship between lens vault (LV), visual acuity (VA), and refraction. Methods: This was a cross-sectional study of 2047 subjects aged 50 years and older recruited from a community polyclinic. Anterior segment optical coherence tomography was performed, and cus- tomized software was used to measure LV. VA was measured using a logarithm of minimum angle of resolution chart (logMAR chart; Lighthouse Inc.), and was classified as normal (logMAR < 0.3), mild impairment (0.3 < logMAR < 0.6), and moderate/severe impairment (logMAR > 0.6). Refraction was measured with an autorefractor machine and spherical equivalent was defined as sphere plus half cylinder. Angle closure was defined as posterior trabecular meshwork not visible for Z2 quadrants on non- indentation gonioscopy. Results: Complete data were available for 1372 subjects including 295 (21.5%) with angle closure. Angle-closure subjects were sig- nificantly older (P < 0.001), with shorter axial length (P < 0.001), shallower anterior chamber depth (P < 0.001), and greater LV (P < 0.001). There was no significant difference in VA (P = 0.12) compared with those without angle closure. After adjusting for age, sex, axial length, anterior chamber depth, and spherical equivalent, there was no significant association between LV and VA (P = 0.35) or between LV and spherical equivalent (P = 0.06). Conclusions: The magnitude of LV was not associated with VA or spherical equivalent. Lens extraction may be a consideration in eyes with angle closure with large LV in the absence of visually significant cataract. Key Words: lens vault, visual acuity, angle closure (J Glaucoma 2016;25:e236–e240) T he lens plays an important role in the pathogenesis of primary angle-closure glaucoma (PACG). 1–3 In addi- tion to the thickness and position of the lens, another parameter, found to be associated with angle closure is the lens vault (LV). 4 The LV, imaged by anterior segment optical coherence tomography (ASOCT), is a surrogate measurement of the amount of lens that is located anterior to the plane of the anterior chamber angles. An increase in LV may worsen angle crowding in an already predisposed eye by instigating a more pronounced iris bowing through relative pupil block, and in more severe cases may also directly push the peripheral iris towards the angles. 4 LV has been found to distinguish eyes with angle closure from those with open angles better than biometric parameters such as anterior chamber depth (ACD), axial length (AL), lens thickness (LT), and lens position. 4 LV is the ASOCT risk factor for angle closure that is most analogous to the lens component. Although an increased LV may either represent an aged lens, an intumescent lens or subluxed lens, the targeted removal of this component converges to a lens extraction. With age, the compaction of crystallins during cata- ractogenesis may lead to an increase in refractive index and a yellowing of the lens itself. This is often accompanied by an increase in LT and a myopic shift related to the devel- opment of nuclear cataract. 5 Studies have shown that for cases of visually significant cataract and PACG, cataract extraction results in deepening of the anterior chamber and widening of the angles, and in some cases, may lower intraocular pressure (IOP) and reduce the likelihood of progression. 6,7 However, there is a lack of consensus on the role of lens extraction in eyes with PACG or primary angle closure with good visual acuity (VA). An ongoing multi- centered randomized-controlled trial, the effectiveness in Angle Closure Glaucoma of Lens Extraction (EAGLE) is currently investigating whether early lens extraction in PACG improves patient-reported outcomes and cost- effectiveness compared with standard care. 8 The relationship of LV with VA or refractive error is not known, particularly in eyes with angle closure. Whereas good VA may naturally preclude cataract surgery, an increased LV may support the decision to proceed with cataract surgery even with a VA that was considered “normal” for surgical intervention. The aim of this study was to investigate the relation- ship between LV, VA, and refraction in subjects with angle closure. METHODS Approval for the study was granted by the Singapore Eye Research Institute institutional review board. This study was conducted in accordance with the Declaration of Received for publication July 1, 2014; accepted March 25, 2015. From the *Singapore National Eye Centre, Singapore Eye Research Institute; wDuke-NUS Graduate Medical School; yYong Loo Lin School of Medicine, National University of Singapore, Singapore; and zUniversity College London Medical School, London, UK. M.E.N. and S.S. are joint first authors. Supported by grants from National Medical Research Council, Singapore. Disclosure: The authors declare no conflict of interest. Reprints: Tin Aung, FRCS, PhD, Singapore National Eye Center, Singapore Eye Research Institute, 11 Third Hospital Avenue, Singapore 168751 (e-mail: aung.tin@snec.com.sg). Copyright r 2015 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/IJG.0000000000000264 ORIGINAL STUDY e236 | www.glaucomajournal.com J Glaucoma  Volume 25, Number 3, March 2016 Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.