{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,28]],"date-time":"2026-03-28T20:35:39Z","timestamp":1774730139171,"version":"3.50.1"},"reference-count":30,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2025,5,30]],"date-time":"2025-05-30T00:00:00Z","timestamp":1748563200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Konkuk University"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biosensors"],"abstract":"<jats:p>Understanding the tensile properties of extraocular muscles (EOMs) is crucial for successful strabismus surgery and accurate predictions of surgical outcomes. Assessments of EOM tensile strength are traditionally highly dependent on the expertise of the ophthalmic surgeon, since they involve manually pulling the EOM in opposite directions. This approach only provides subjective measurements that are not quantifiable. Previous quantitative approaches have utilized various devices such as implanted force transducers or dial tension gauges connected to muscle tendons with nylon sutures, but these methods are complex and so are rarely used outside of research settings. Consequently, the goal of this study was to create a quantitative and clinically applicable device for assessing EOM tensile strength. This developed device uses a strabismus hook connected to a strain gauge load cell that measures the tensile force and includes a tilting sensor to ensure that the hook is pulled at a consistent angle when a force is applied. The performance of the device was tested on 22 EOMs in 11 patients with intermittent exotropia during surgery for resecting the medial rectus (MR) and recessing the lateral rectus (LR) under general anesthesia. The measured tensile strengths of the MR and LR were 284.9 \u00b1 58.3 and 278.3 \u00b1 64.6 g (mean \u00b1 SD), respectively. In conclusion, the novel device developed in this study for quantitative measurements of EOM tensile strength in clinical settings will facilitate understanding of the pathophysiology of strabismus, as well as of the mechanical properties of the EOMs, and enhance the precision of surgical interventions.<\/jats:p>","DOI":"10.3390\/bios15060347","type":"journal-article","created":{"date-parts":[[2025,5,30]],"date-time":"2025-05-30T09:22:41Z","timestamp":1748596961000},"page":"347","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Novel Device for Intraoperative Quantitative Measurements of Extraocular Muscle Tensile Strength"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3563-8042","authenticated-orcid":false,"given":"Hyun Jin","family":"Shin","sequence":"first","affiliation":[{"name":"Department of Ophthalmology, Konkuk University School of Medicine, Chungju 27478, Republic of Korea"},{"name":"Department of Ophthalmology, Konkuk University Medical Center, Seoul 05030, Republic of Korea"},{"name":"Research Institute of Medical Science, Konkuk University, Seoul 05030, Republic of Korea"},{"name":"Institute of Biomedical Science & Technology, Konkuk University, Seoul 05030, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Minung","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Mechatronics Engineering, Konkuk University Glocal Campus, 268 Chungwondae-ro, Chungju-si 27478, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9664-1563","authenticated-orcid":false,"given":"Hyunkyoo","family":"Kang","sequence":"additional","affiliation":[{"name":"Department of Mechatronics Engineering, Konkuk University Glocal Campus, 268 Chungwondae-ro, Chungju-si 27478, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2473-299X","authenticated-orcid":false,"given":"Andrew G.","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Blanton Eye Institute, Houston Methodist Hospital, Houston, TX 77030, USA"},{"name":"Department of Ophthalmology, Neurology, Neurosurgery, Weill Cornell Medicine, New York, NY 10065, USA"},{"name":"Department of Ophthalmology, University of Texas Medical Branch, Galveston, TX 77555, USA"},{"name":"Department of Ophthalmology, UT MD Anderson Cancer Center, Houston, TX 77030, USA"},{"name":"Department of Ophthalmology, Texas A and M College of Medicine, College Station, TX 77807, USA"},{"name":"Department of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA"},{"name":"Department of Ophthalmology, Baylor College of Medicine and the Center for Space Medicine, Houston, TX 77030, USA"},{"name":"Department of Ophthalmology, University of Buffalo, Buffalo, NY 14214, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,5,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"5810","DOI":"10.1167\/iovs.16-20438","article-title":"The Relationship Between Fusion, Suppression, and Diplopia in Normal and Amblyopic Vision","volume":"57","author":"Spiegel","year":"2016","journal-title":"Investig. Ophthalmol. Vis. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1016\/j.visres.2015.02.009","article-title":"Amblyopia and the binocular approach to its therapy","volume":"114","author":"Hess","year":"2015","journal-title":"Vis. Res."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"5646","DOI":"10.1167\/iovs.10-5523","article-title":"Effects of recession versus tenotomy surgery without recession in adult rabbit extraocular muscle","volume":"51","author":"Christiansen","year":"2010","journal-title":"Investig. Ophthalmol. Vis. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2841","DOI":"10.1007\/s00417-020-04848-9","article-title":"New instrument for quantitative measurements of passive duction forces and its clinical implications","volume":"258","author":"Kang","year":"2020","journal-title":"Graefes Arch. Clin. Exp. Ophthalmol."},{"key":"ref_5","first-page":"223","article-title":"Measurements of active and passive force of horizontal muscles in strabismus","volume":"32","author":"Iwashige","year":"1988","journal-title":"Jpn. J. Ophthalmol."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Shin, H.J., Lee, S.J., Oh, C.S., and Kang, H. (2020). Novel compact device for clinically measuring extraocular muscle (EOM) tension. J. Biomech., 109.","DOI":"10.1016\/j.jbiomech.2020.109955"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1243\/PIME_PROC_1991_205_275_02","article-title":"Quantitative mechanical assessment of the extraocular muscles","volume":"205","author":"Barbenel","year":"1991","journal-title":"Proc. Inst. Mech. Eng."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"126","DOI":"10.3928\/0191-3913-19870501-07","article-title":"Theoretical effects of surgery on length tension relationships in extraocular muscles","volume":"24","author":"Kushner","year":"1987","journal-title":"J. Pediatr. Ophthalmol. Strabismus"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1005","DOI":"10.2214\/ajr.179.4.1791005","article-title":"Using morphologic parameters of extraocular muscles for diagnosis and follow-up of Graves\u2019 ophthalmopathy: Diameters, areas, or volumes?","volume":"179","author":"Toth","year":"2002","journal-title":"Am. J. Roentgenol."},{"key":"ref_10","first-page":"11","article-title":"Management of Thyroid Eye Disease-Related Strabismus","volume":"23","author":"Akbari","year":"2020","journal-title":"J. Curr. Ophthalmol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"601","DOI":"10.1007\/s10237-023-01794-3","article-title":"Finite element model of ocular adduction with unconstrained globe translation","volume":"23","author":"Jafari","year":"2024","journal-title":"Biomech. Model. Mechanobiol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"869","DOI":"10.3233\/JND-230023","article-title":"Eye Muscle MRI in Myasthenia Gravis and Other Neuromuscular Disorders","volume":"10","author":"Keene","year":"2023","journal-title":"J. Neuromuscular Dis."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Zieli\u0144ski, G., Matysik-Wo\u017aniak, A., Pankowska, A., Pietura, R., Rejdak, R., and Jonak, K. (2023). High Myopia and Thickness of Extraocular and Masticatory Muscles\u20147T MRI, Preliminary Study. J. Clin. Med., 12.","DOI":"10.3390\/jcm12124166"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1515\/cdbme-2024-0103","article-title":"Force Feedback Reduces Test Time and Interaction Forces in Telemanipulated Palpation Using a Robotic Endoscope with Series Elastic Actuated Joints","volume":"10","author":"Ettori","year":"2024","journal-title":"Curr. Dir. Biomed. Eng."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Xie, K., Luan, N., Zhu, X., and Cao, Q. (2020, January 24\u201325). Implementation of 7-DOF External Force\/Torque Feedback for Master-Slave Surgical Robot System. Proceedings of the 13th International Conference on Intelligent Computation Technology and Automation (ICICTA), Xi\u2019an, China.","DOI":"10.1109\/ICICTA51737.2020.00144"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Shin, H.J., Kim, S., Kang, H., and Lee, A.G. (2023). Novel Instrument for Clinical Evaluations of Active Extraocular Muscle Tension. Appl. Sci., 13.","DOI":"10.3390\/app132011431"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Kang, H., Shin, H.J., and Lee, A.G. (2023). Risk of consecutive esotropia after surgery for intermittent exotropia according to passive duction force. PLoS ONE, 16.","DOI":"10.1371\/journal.pone.0281392"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1617","DOI":"10.1007\/s00417-020-05030-x","article-title":"Quantitative measurement of passive duction force tension in intermittent exotropia and its clinical implications","volume":"259","author":"Kang","year":"2021","journal-title":"Graefes Arch. Clin. Exp. Ophthalmol."},{"key":"ref_19","first-page":"652","article-title":"Extraocular muscle forces in normal human subjects","volume":"20","author":"Collins","year":"1981","journal-title":"Investig. Ophthalmol. Vis. Sci."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1007\/s00417-005-0183-4","article-title":"Isometric force measured in human horizontal eye muscles attached to or detached from the globe","volume":"244","author":"Lennerstrand","year":"2006","journal-title":"Graefes Arch. Clin. Exp. Ophthalmol."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Kim, S., Yang, H.K., and Hwang, J.M. (2018). Surgical outcomes of unilateral recession and resection in intermittent exotropia according to forced duction test results. PLoS ONE, 13.","DOI":"10.1371\/journal.pone.0200741"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1038\/eye.1996.66","article-title":"Factors influencing the successful outcome and response in strabismus surgery","volume":"10","author":"Abbasoglu","year":"1996","journal-title":"Eye"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Leffler, C.T., Woock, A., Shinbashi, M., and Suggs, M. (2024). Variation between surgeons in reoperation rates following vertical strabismus surgery: Associations with patient and surgeon characteristics and adjustable sutures. PLoS ONE, 7.","DOI":"10.1371\/journal.pone.0310371"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1113\/jphysiol.1975.sp010850","article-title":"Muscle tension during unrestrained human eye movements","volume":"245","author":"Collins","year":"1975","journal-title":"J. Physiol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"e135","DOI":"10.1016\/j.bjoms.2012.04.260","article-title":"Use of a dial tension gauge to assess quantitatively the intraoperative improvement of ocular movement after endoscopic transantral repair of fracture of the orbital floor","volume":"51","author":"Iwai","year":"2013","journal-title":"Br. J. Oral Maxillofac. Surg."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"837","DOI":"10.1111\/j.1755-3768.2008.01375.x","article-title":"Isometric force development in human horizontal eye muscles and pulleys during saccadic eye movements","volume":"87","author":"Lennerstrand","year":"2009","journal-title":"Acta Ophthalmol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"230","DOI":"10.1109\/10.133203","article-title":"Length-tension recording system for strabismus surgery","volume":"38","author":"Collins","year":"1991","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Yang, G., Lin, R., Li, H., Chen, Y., Liu, M., Luo, Z., Wang, K., Tu, J., Xu, Y., and Fan, Z. (2025). Implantable wireless suture sensor for in situ tendon and ligament strain monitoring. Sci Adv., 11.","DOI":"10.1126\/sciadv.adt3811"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Niu, Y., Qin, Z., Zhang, Y., Chen, C., Liu, S., and Chen, H. (2023). Expanding the potential of biosensors: A review on organic field effect transistor (OFET) and organic electrochemical transistor (OECT) biosensors. Mater. Futures, 2.","DOI":"10.1088\/2752-5724\/ace3dd"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2181","DOI":"10.1021\/acssensors.4c03487","article-title":"Ultrafast Hydrogen Detection System Using Vertical Thermal Conduction Structure and Neural Network Prediction Algorithm Based on Sensor Response Process","volume":"10","author":"Yang","year":"2025","journal-title":"ACS Sens."}],"container-title":["Biosensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-6374\/15\/6\/347\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:44:00Z","timestamp":1760031840000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-6374\/15\/6\/347"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,5,30]]},"references-count":30,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2025,6]]}},"alternative-id":["bios15060347"],"URL":"https:\/\/doi.org\/10.3390\/bios15060347","relation":{},"ISSN":["2079-6374"],"issn-type":[{"value":"2079-6374","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,5,30]]}}}