Inner retinal layers' alterations of the microvasculature in early stages of Parkinson's disease: a cross sectional study.

PURPOSE: To investigate microcirculation characteristics of the inner retinal layers at the macula and the peripapillary area using Optical Coherence Tomography Angiography (OCT-A) of patients in early stages of Parkinson's disease (PD). METHODS: 32 PD patients and 46 age- and gender-matched healthy controls were included in this cross sectional study. OCT-A imaging was performed to analyze microcirculation characteristics at each separate macular region (fovea, parafovea, and perifovea) and the peripapillary area of the inner retinal layers. RESULTS: Individuals with PD had significantly lower parafoveal, perifoveal and total vessel density (VD) in the superficial capillary plexus (SCP) than controls (all p < 0.001), while foveal VD was higher in PD eyes than that of controls, though not statistically significant. Similarly, individuals with PD had significantly lower parafoveal, perifoveal and total perfusion in the SCP than control eyes (all p < 0.001), while foveal perfusion was significantly higher in PD eyes than that of controls (p = 0.008). PD eyes had significantly smaller FAZ area and perimeter accompanied by decreased circularity at the SCP as compared to controls (all p < 0.001). Concerning the peripapillary area, individuals with PD had significantly lower radial peripapillary capillary perfusion density and flux index at the SCP than controls (all p < 0.001). All p values remained statistically significant even after using the Bonferroni correction for multiple comparisons, except for that of foveal perfusion. CONCLUSIONS: Our study indicates alterations of the inner retinal layers at the macula and the peripapillary area at the preliminary stages of PD. OCT-A parameters could potentially comprise imaging biomarkers for PD screening and improve the diagnostic algorithms.

Assessment of Maternal Retinal Microvasculature in Preterm Pregnancy Using OCT-Angiography: a Cross-Sectional Study.

Background: Pregnancy induces a cascade of hemodynamic changes that are likely to affect the maternal systemic and ocular circulation. Objective:The current study aimed to investigate retinal microvasculature alterations in women with preterm and full-term pregnancy using optical coherence tomography angiography (OCT-A). Design:This was a cross-sectional, comparative, single-center study. Methods:The present study included 21 women with preterm pregnancy, who were in the early postpartum period, and 18 controls with full-term pregnancy. Optical coherence tomography angiography imaging was performed to analyze macular microvasculature characteristics at the retinal superficial capillary plexus (SCP) and the choriocapillaris (CC). Results:In females with preterm pregnancy, the mean values of vessel density (VD) at the SCP of the total macular area were significantly higher than those in females with full-term pregnancy (p=0.001), and the mean values of foveal, parafoveal and perifoveal VD at the SCP were higher, though not statistically significant. Similarly, the mean values of perfusion at the SCP of the total macular area were significantly higher in females with preterm pregnancy than controls (p=0.023), while the mean values of foveal, parafoveal and perifoveal perfusion were higher, though not statistically significant. The mean values of foveal avascular zone (FAZ) parameters (area, perimeter, circularity) at the SCP in females with preterm pregnancy did not have any significant differences from those of controls. Concerning the measurements of choroidal parameters, there were no statistically significant differences in subfoveal choroidal thickness, as well as the CC OCT-A characteristics between females with preterm and full-term pregnancy. Conclusions:Our study indicates that retinal blood flow alterations may be present in the early postpartum period in women with preterm pregnancy. Increased macular vasculature may reflect the systemic perfusion changes compensating for placental insufficiency.

Retinal microcirculation characteristics in obstructive sleep apnea/hypopnea syndrome evaluated by OCT-angiography: a literature review.

PURPOSE: The retina may provide a window to estimate systemic vascular status; therefore, there has been interest in identifying microcirculation characteristics that possibly reflect hypoxic alterations in obstructive sleep apnea/hypopnea syndrome (OSAS). Emerging evidence has suggested that retinal microvasculature investigation holds the potential to characterize the pathophysiology involved in ocular manifestations of OSAS. The advent of optical coherence tomography angiography (OCT-A) has attracted significant attention as this technique offers detailed analysis of the retinal capillary plexus. METHODS: A detailed literature search was performed in PubMed database until December 2021. We identified and reviewed all papers referring to the alterations of the retinal capillary plexus in OSAS using OCT-A. RESULTS: A comprehensive update indicates that microcirculation alterations of the retinal capillary plexus utilizing OCT-A may differ with severity of OSAS and imply the potential underlying pathophysiology of ocular manifestations. The reviewed series have revealed variability concerning microvasculature characteristics at the macular and the peripapillary area. Further studies are warranted to establish the OCT-A parameters as biomarkers regarding the evaluation of OSAS in clinical practice. CONCLUSION: Retinal capillary plexus characteristics as seen on OCT-A reflect microvasculature alterations, potentially leading to concomitant ocular comorbidity in the context of OSAS. The reviewed literature may confirm the diagnostic and prognostic value of OCT-A in the assessment of the pathophysiology of ocular manifestations in OSAS and highlight unmet needs to be addressed by future research.

Macular microcirculation characteristics in Parkinson's disease evaluated by OCT-Angiography: a literature review.

PURPOSE: Given the fact that retina may provide a window into the central nervous system, there has been interest in identifying retinal biomarkers as predicting factors of pathological processes in neurodegenerative disorders. Emerging evidence has suggested that macular microcirculation changes in Parkinson disease (PD) may indicate the alterations of cerebral microvasculature. The use of Optical Coherence Tomography Angiography (OCT-A) has attracted significant attention in recent years as this technique offers a detailed analysis of the existence of changes at the macular capillary plexus. METHODS: A detailed review of the literature was performed in PubMed until June 2021. We identified all papers referring to the alterations of the macular capillary plexus in PD using OCT-A. RESULTS: A comprehensive update indicates that microvasculature alterations of the macular capillary plexus utilizing OCT-A may comprise useful biomarkers regarding the cerebral vasculature in PD. Since the available evidence is limited, additional studies are warranted to establish the OCT-A parameters as predicting factors in clinical practice. CONCLUSIONS: A review of the existing literature sheds light on the microvasculature changes of the macular capillary plexus as seen on OCT-A in PD patients. The current article discusses notable aspects of key publications on the topic, highlights the importance of the potential long-term effectiveness of OCT-A biomarkers in PD and proposes the need for further future research.

A Narrative Review of the Ocular Manifestations in Noonan Syndrome.

PURPOSE: The purpose of this review is to provide an update on ophthalmological manifestations of Noonan Syndrome (NS). Emerging evidence has suggested that NS patients may present with a wide spectrum of ocular characteristics. Detailed investigation of genotype has revealed the diversity of related gene mutations. The potential association of genetic basis with clinical expressivity of phenotype remains a challenging aspect of this issue. METHODS: A literature search was performed in PubMed; we have analyzed prospective and retrospective cohort studies, case reports, and reference lists of retrieved articles until February 2021. We identified all papers referring to NS ocular manifestations referring to genotype and phenotype characteristics. RESULTS: A comprehensive update on ocular manifestations of NS patients indicates significant evidence for variability of genotype and phenotype features. Ophthalmologic features of NS are characterized by a wide spectrum of abnormalities; external ocular malformations, distortions of refraction, alignment, motilily, anterior and posterior ocular segment and visual impairment. Currently, a variety of pathogenic mutations in patients with NS have been investigated, while the nature of the genetic variants may determine expressivity. Albeit it remains a clinical diagnosis with variation in the progress of each NS phenotype. Although the available evidence that is needed to establish genotype-phenotype correlation as predicting factor in clinical practice is limited, it could aid risk assessment and patient management. CONCLUSION: A review of the existing literature sheds light on the ocular characteristics of NS. The current article discusses notable aspects of key publications on the topic, highlights the importance of the potential genotype-phenotype correlation in clinical practice, and proposes the need for further future research.