State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
School of Automation, Guangdong University of Technology, Guangzhou, China.
JMIR Mhealth Uhealth. 2019 Jun 26;7(6):e14592. doi: 10.2196/14592.
Pars plana vitrectomy (PPV) with intravitreous tamponade of gas or air has been widely used for a series of vitreoretinal diseases. It is estimated that 100,000 patients per year undergo PPV globally, and half of them were subsequently tamponaded with gas or air. According to Boyle's law (PV=PV), patients with an intravitreous remnant of gas or air will be under high risk of intraocular pressure (IOP) elevation and subsequent vision loss owing to the expanded intravitreous gas or air when traveling post operation to a place with a significantly higher altitude. We always explain to patients why postoperative travel is potentially risky. Emergency cases of elevated IOP caused by postoperative traveling would sometimes come to surgeons. However, there have been few disease education or reference tools for both the surgeons and patients to have better communication.
The aim of this study was to introduce and evaluate a mobile phone app developed by surgeons (the authors) for preliminary risk estimation of volume expansion and IOP elevation in patients with intravitreous gas or air when traveling to a place of higher altitude.
The app was developed on the iOS and Android operating systems. Boyle's law (PV=PV) was the theoretical basis of the app. Intravitreous gas or air volume and altitude values were independent factors to deduce the risk report. Consecutive patients underwent vitrectomy, and those with an intravitreous remnant of gas or air were recruited. The surgeons judged the vertical height of the fluid/gas interface through the dilated pupil; the patients were instructed to judge it according to their visual field when looking straight ahead and line it out on a chart included in the app. Finally, all the patients were required to fill a Likert scale-based questionnaire with 2 main items to evaluate the participants' user experience and attitudes toward the app.
A total of 50 patients were included (30 males and 20 females). All patients could independently operate the app to complete the test. The median heights of the fluid/gas interface independently judged by the surgeon and patients were 40% (range: 10%-75%) and 41% (range: 9%-78%), respectively (P=.63). The median altitude of the participants' destinations was 150.0 m (range: 0-3490 m). The Bland-Altman analysis revealed a good agreement between the surgeons' and patients' judgments (bias of -0.3%), with 95% limits of agreement of -5.8% to 5.3%. Overall, the Likert scale revealed a positive attitude from the patients toward the app.
The app is reliable for patients to have preliminary risk estimation of intravitreous gas or air volume expansion and IOP elevation if travel to a place of higher altitude is planned. The surgeons could also use it as a platform for better disease communication.
玻璃体切除术（PPV）联合眼内气体或空气填充已广泛应用于一系列玻璃体视网膜疾病的治疗。据估计，全球每年有 10 万名患者接受 PPV 治疗，其中一半患者随后接受了气体或空气填充。根据玻意耳定律（PV=PV），当术后前往海拔较高的地方时，眼内残余气体或空气的患者将面临眼压（IOP）升高和视力下降的高风险，因为膨胀的眼内气体或空气会导致眼压升高。我们总是向患者解释为什么术后旅行存在潜在风险。由于术后旅行引起的 IOP 升高的紧急情况有时会发生在外科医生身上。然而，目前还没有为外科医生和患者提供更好沟通的疾病教育或参考工具。
本研究旨在介绍并评估一款由外科医生（作者）开发的手机应用程序，用于初步评估眼内气体或空气填充的患者在前往高海拔地区时，眼内气体或空气体积膨胀和眼压升高的风险。
该应用程序是在 iOS 和 Android 操作系统上开发的。玻意耳定律（PV=PV）是该应用程序的理论基础。眼内气体或空气体积和海拔值是推断风险报告的独立因素。连续接受玻璃体切除术治疗且眼内有残余气体或空气的患者被招募入组。外科医生通过散瞳后的瞳孔判断液体/气体界面的垂直高度；嘱患者直视前方时根据视野进行判断，并在应用程序中包含的图表上进行标记。最后，所有患者都需要填写一份基于李克特量表的问卷，其中包含 2 个主要项目，以评估参与者对应用程序的用户体验和态度。
共有 50 名患者入组（男性 30 名，女性 20 名）。所有患者均能独立操作应用程序完成测试。外科医生和患者独立判断的液体/气体界面的中位数高度分别为 40%（范围：10%-75%）和 41%（范围：9%-78%）（P=.63）。参与者目的地的中位数海拔高度为 150.0 m（范围：0-3490 m）。Bland-Altman 分析显示，外科医生和患者的判断之间具有良好的一致性（偏差为-0.3%），95%一致性界限为-5.8%至 5.3%。总体而言，李克特量表显示患者对该应用程序持积极态度。
如果计划前往高海拔地区，该应用程序可帮助患者初步评估眼内气体或空气体积膨胀和眼压升高的风险。外科医生也可以将其用作更好地进行疾病沟通的平台。
