Retinal oxygen extraction during systemic hypoxia assessed with laser-speckle flowgraphy and retinal oximetry

IF 2.8 3区医学 Q1 OPHTHALMOLOGY Acta Ophthalmologica Pub Date : 2025-01-19 DOI:10.1111/aos.17326

Viktoria Pai, Theresa Lindner, Patrick Janku, Leopold Schmetterer, Doreen Schmidl, Gerhard Garhöfer

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Abstract

Aims/Purpose: Retinal oxygen extraction has been found to be altered in several ocular and systemic diseases, such as diabetic retinopathy, glaucoma or neurodegenerative diseases. However, measurement techniques for the assessment of retinal oxygen extraction are limited because most of them are based on time-consuming and custom-built devices. In the present pilot study, we assessed retinal oxygen extraction during systemic hypoxia with a combination of two commercially available devices: Laser-Speckle Flowgraphy (LSFG) and retinal oximetry.

Methods: Retinal blood flow and retinal oxygen saturation were measured in each vessel around the optic nerve head at the same position. Arterial and venous oxygen content was estimated from the measured retinal oxygen saturation parameters and the difference between these two parameters was calculated (cO₂,_DIFF). By using mean vessel flow rate (MV) for retinal blood flow and cO₂,_DIFF, retinal oxygen extraction was determined. For each healthy study participant, baseline measurement and measurement during inhalation of 88% nitrogen in 12% oxygen were performed.

Results: Ten (10) healthy subjects (4 females, 6 males) with a mean age of 27 ± 3 years were included in this study. During systemic hypoxia, a significant decrease in arterial oxygen content occurred (p = 0.046) while venous oxygen content did not change, leading to a decrease in cO₂,_DIFF. As expected, this was accompanied by a significant increase in MV (p = 0.014). No change in retinal oxygen extraction was observed (46 ± 8 a.u. at baseline vs. 46 ± 5 a.u. during hypoxia, p = 0.997).

Conclusions: Breathing of 88% nitrogen in 12% oxygen caused a significant decrease in retinal arterial oxygen content. This was compensated by an increase in retinal blood flow in order to keep retinal oxygen extraction constant. This was physiologically expected, and these findings are consistent with the literature. Therefore, the presented approach for measurement of retinal oxygen extraction appears to be feasible.

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用激光散斑血流图和视网膜血氧仪评估全身性缺氧时的视网膜氧提取

目的/目的：在一些眼部和全身性疾病，如糖尿病视网膜病变、青光眼或神经退行性疾病中，视网膜氧提取已被发现发生改变。然而，评估视网膜氧提取的测量技术是有限的，因为它们大多是基于耗时和定制的设备。在目前的初步研究中，我们评估了在全身缺氧时视网膜氧气提取与两种市售设备的组合：激光散斑血流成像（LSFG）和视网膜血氧仪。方法：测定视神经头周围同一位置各血管的视网膜血流量和视网膜血氧饱和度。根据测量的视网膜氧饱和度参数估计动脉和静脉氧含量，并计算两者之间的差值（cO2，DIFF）。用平均血管流速（MV）和cO2、DIFF测定视网膜血流量。对于每个健康的研究参与者，进行基线测量和吸入12%氧气中88%氮气时的测量。结果：纳入健康受试者10例（女4例，男6例），平均年龄27±3岁。全身缺氧时，动脉氧含量显著降低（p = 0.046），而静脉氧含量无变化，导致cO2、DIFF降低。正如预期的那样，这伴随着MV的显著增加（p = 0.014）。视网膜吸氧量无变化（基线时46±8 a.u.，缺氧时46±5 a.u., p = 0.997）。结论：12%氧配88%氮气呼吸可导致视网膜动脉血氧含量显著降低。这是通过增加视网膜血流量来补偿的，以保持视网膜氧气提取的恒定。这是生理上的预期，这些发现与文献一致。因此，所提出的测量视网膜氧提取的方法似乎是可行的。

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来源期刊

Acta Ophthalmologica 医学-眼科学

CiteScore

7.60

自引率

5.90%

发文量

433

审稿时长

6 months

期刊介绍： Acta Ophthalmologica is published on behalf of the Acta Ophthalmologica Scandinavica Foundation and is the official scientific publication of the following societies: The Danish Ophthalmological Society, The Finnish Ophthalmological Society, The Icelandic Ophthalmological Society, The Norwegian Ophthalmological Society and The Swedish Ophthalmological Society, and also the European Association for Vision and Eye Research (EVER). Acta Ophthalmologica publishes clinical and experimental original articles, reviews, editorials, educational photo essays (Diagnosis and Therapy in Ophthalmology), case reports and case series, letters to the editor and doctoral theses.