Yap Zhu Li, Ong Charles, Lee Yi Fang, Tsai Andrew, Cheng Clarissa, Nongpiur Monisha E, Perera Shamira A
*Singapore National Eye Centre ‡Singapore Eye Research Institute †Yong Loo Lin School of Medicine, National University of Singapore.
J Glaucoma. 2017 Apr;26(4):367-372. doi: 10.1097/IJG.0000000000000622.
Although some studies suggest a strong link between retinal vessel oxygenation and damage to the retinal nerve fiber layer (RNFL) seen in glaucoma, it has yet to be conclusively proven. This study compares intraocular retinal oximetry in glaucomatous eyes displaying asymmetrically affected hemifields across different subgroups of glaucoma, namely primary angle closure glaucoma (PACG), primary open-angle glaucoma (POAG), and normal tension glaucoma (NTG).
In this prospective cross-sectional study, 99 patients (PACG, n=28; POAG, n=37; NTG, n=34) underwent retinal oxygenation and vessel caliber measurements using the Oxymap T1 Retinal Oximeter, Cirrus optical coherence tomography, and Humphrey visual field testing. For the comparison between different subtypes of glaucoma, an analysis of variance with Bonferroni method was performed. Intraeye differences were compared with a paired t test. Determination of the more affected and less affected hemifield was made using the Humphrey visual field pattern deviation plot.
Considering the mean deviation and Advanced Glaucoma Interventional Study score, the visual field defects were milder in NTG as compared with POAG and PACG (P<0.05).Arteriole diameter was smaller in the more affected hemifield compared with the less affected hemifield in patients with PACG (109.30±18.07 vs. 120.57±17.92; P=0.023) and NTG (109.36±13.79 vs. 117.46±17.72; P=0.04). The more affected hemifield had a significantly thinner RNFL than the less affected hemifield in patients across all 3 groups, though this was only significant in PACG (P=0.02) and NTG patients (P<0.01). In all 3 groups, although the less affected hemifield tended to have a marginally higher arteriole and venule oxygen saturation than the more affected hemifield, no statistical significance was reached. There were no significant differences in arteriovenous difference between the more and less affected hemifield in all 3 groups.
In our study, localized visual field losses were not associated with changes in retinal oximetry but were associated with narrower retinal arteriolar diameters in PACG and NTG. The RNFL was thinner in the more affected hemifield in these 2 groups but this was not so marked in the POAG sample, possibly limiting our ability to find a difference in arteriolar diameter there.
尽管一些研究表明视网膜血管氧合与青光眼患者视网膜神经纤维层（RNFL）损伤之间存在紧密联系，但尚未得到确凿证实。本研究比较了青光眼不同亚组（即原发性闭角型青光眼（PACG）、原发性开角型青光眼（POAG）和正常眼压性青光眼（NTG））中，半视野受不对称影响的青光眼患眼的眼内视网膜血氧饱和度。
在这项前瞻性横断面研究中，99例患者（PACG组28例；POAG组37例；NTG组34例）接受了视网膜氧合和血管管径测量，使用的设备包括Oxymap T1视网膜血氧计、Cirrus光学相干断层扫描以及Humphrey视野检测。为比较不同亚型青光眼之间的差异，采用Bonferroni法进行方差分析。眼内差异采用配对t检验进行比较。使用Humphrey视野模式偏差图确定受影响程度较高和较低的半视野。
考虑平均偏差和高级青光眼干预研究评分，NTG患者的视野缺损比POAG和PACG患者更轻（P<0.05）。在PACG患者（109.30±18.07 vs. 120.57±17.92；P=0.023）和NTG患者（109.36±13.79 vs. 117.46±17.72；P=0.04）中，受影响程度较高的半视野的小动脉直径比受影响程度较低的半视野更小。在所有3组患者中，受影响程度较高的半视野的RNFL比受影响程度较低的半视野更薄，不过仅在PACG患者（P=0.02）和NTG患者（P<0.01）中具有统计学意义。在所有3组中，尽管受影响程度较低的半视野的小动脉和小静脉血氧饱和度往往略高于受影响程度较高的半视野，但未达到统计学显著性。所有3组中，受影响程度较高和较低的半视野之间的动静脉差异均无显著差异。
在我们的研究中，局限性视野缺损与视网膜血氧饱和度变化无关，但与PACG和NTG患者视网膜小动脉直径变窄有关。在这两组中，受影响程度较高的半视野的RNFL更薄，但在POAG样本中并不明显，这可能限制了我们在该组中发现小动脉直径差异的能力。
