Abstract
Purpose :
Quantitative measurement of spectral-domain optical coherence tomography angiography (OCTA) was used to compare the difference of microcirculatory in subjects with or without obstructive sleep apnea syndrome (OSAS), and to further detect whether a circadian microcirculatory change exists in OSAS patients.
Methods :
40 OSAS patients and 32 controls were enrolled and divided into 4 groups according to the apnea-hypopnea index (AHI). they are respectively defined as normal group(AHI＜5), mild group(5＜AHI <15, 13 eyes), moderate group (15≤AHI <30,13 eyes), or severe group (AHI≥30,14 eyes). All OSAS patients went through polysomnography, and OCTA RT XR Avanti (AngioVue software, Optovue Inc., Fremont, CA) scans before and after performing polysomnography. Clinical data and ocular features like BMI, sex, age, Axial length, intraocular pressure, CCT, BCVA were routinely recorded. When performing scans on Optovue, retinal nerve fiber layer (RNFL), ganglion cell complex(GCC), macular vessel density of superficial and deep layers, capillary densities of RPC layer were collected and evaluated.
Results :
The four groups were similar in terms of age, body mass index, axial length, best corrected visual acuity, IOP (all P > 0.05). It was found that the retinal vessel density decreased with greater severity of OSAS from normal to moderate to some extent, however, no similar tendency was discovered between the normal and severe group. The moderate group had a significantly lower vessel density than the control group in deep layer of the nasal-parafovea section and nasal-perifovea section (t=2.071, p=0.045; t=2.151, p=0.037). OSAS patients with moderate apnea also had a significantly lower vessel density in both deep and superficial layer of the fovea (t=2.459, p=0.027; t=2.259, p=0.039). The capillary densities of RPC layer in the inferior-hemi peripapillary section had a significant reduction compared with control groups (t=2.885, p=0.049). Neither the superficial layer nor deep layer detected significant changes of macular vessel density when comparing the scan series of day and night.
Conclusions :
No circadian microcirculation pattern is founded in any group of OSAS patient. However, OCTA could detect a reduction of certain sections between normal subjects and moderate OSAS patients. The precise Mechanisms remains unclear.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.