Department of Ophthalmology, Phramongkutklao Hospital, Phramongkutklao College of Medicine, Bangkok, Thailand.
Medicine (Baltimore). 2023 Sep 8;102(36):e34874. doi: 10.1097/MD.0000000000034874.
Intraocular pressure (IOP) is one of the most crucial aspects for diagnosis and treatment plan among patients with glaucoma. Although the gold standard for IOP measurement is Goldmann applanation tonometer (GAT)[1], it must be mounted to a slit lamp biomicroscope. However, rebound tonometer has become popular due to its ease of operation and portable design, does not require topical anesthesia, and results do not differ significantly from those of GAT[2]. The purpose of this cross-sectional study is to investigate the difference in IOP measurement with iCare IC200 in different angles of the eye and different corneal locations. All participants underwent IOP measurement by GAT twice. Then, IOP was measured with iCare by a single physician. IOP was measured in a straight manner in the upright patient position; then participants were asked to look at fixation targets, which located in four different points. IOP was measured in upgaze, downgaze, medial gaze, and lateral gaze. Then, IOP was measured at 2 mm from limbus in superior, inferior, nasal, and temporal cornea. All methods were measured twice, and the mean was used for calculation. The physician who measured IOP by iCare was masked from GAT results. A total of 168 eyes were tested with a mean age of 62.15 ± 12.34 years. Mean IOP measured by GAT and iCare at the central cornea was 15.53 ± 5.57 and 14.78 ± 6.14 mmHg, respectively. The standardized mean difference (SMD) between iCare and GAT was 0.13 (-0.09-0.34), which is insignificant. The average IOP was 0.6, 0.47, 0.91, and 0.44 mmHg lower than the primary position in upgaze, downgaze, medial gaze, and lateral gaze 15 degrees angulated positions respectively (p<.01). IOPs at 2 mm from limbus in the inferior, nasal, and temporal cornea were 0.5, 0.69, and 0.57 mmHg lower than IOP measured at the central cornea (p=<.01). IOP measurements with iCare in different angles of eye were statistically significantly lower than in the primary position. Similarly, IOPs at different locations on cornea were lower than at the central cornea. However, the difference in IOP measurements with iCare in different angles of the eye and different corneal locations was in the trivial range and might be clinically insignificant.
眼压（IOP）是青光眼患者诊断和治疗计划中最重要的方面之一。尽管眼压测量的金标准是 Goldmann 压平眼压计（GAT）[1]，但它必须安装在裂隙灯生物显微镜上。然而，回弹眼压计因其操作简便、设计便携、无需表面麻醉以及结果与 GAT 无显著差异而广受欢迎[2]。本横断面研究的目的是探讨 iCare IC200 在眼睛不同角度和角膜不同位置测量 IOP 的差异。所有参与者均接受了两次 GAT 眼压测量。然后，由一名医生使用 iCare 进行眼压测量。在直立患者体位下，以直线方式测量 IOP；然后要求参与者注视四个不同点的固定目标。测量上视、下视、内视和外视时的 IOP。然后，在角膜缘 2mm 处测量上、下、鼻、颞侧角膜的 IOP。所有方法均测量两次，取平均值进行计算。测量 iCare 眼压的医生对 GAT 结果不知情。共测试了 168 只眼睛，平均年龄为 62.15±12.34 岁。中央角膜 GAT 和 iCare 测量的平均眼压分别为 15.53±5.57mmHg 和 14.78±6.14mmHg。iCare 和 GAT 之间的标准化平均差值（SMD）为 0.13（-0.09-0.34），无统计学意义。上视、下视、内视和外视 15 度偏角时，平均眼压分别比原发性位置低 0.6、0.47、0.91 和 0.44mmHg（p<.01）。下、鼻、颞侧角膜缘 2mm 处的眼压分别比中央角膜处低 0.5、0.69 和 0.57mmHg（p<.01）。iCare 在眼睛不同角度的眼压测量值明显低于原发性位置。同样，角膜不同位置的眼压也低于中央角膜。然而，iCare 在眼睛不同角度和角膜不同位置测量眼压的差异处于微不足道的范围内，可能在临床上没有意义。
