Characteristics of laterality in the optic nerve head microcirculation obtained by laser speckle flowgraphy in healthy subjects

PURPOSE

To determine the characteristics of the laterality of the ocular microcirculation parameters obtained from laser speckle flowgraphy (LSFG) in the optic nerve head (ONH).

SUBJECTS AND METHODS

We reanalyzed a total of 240 healthy subjects (169 men, 71 women) who had participated in a medical checkup program. We analyzed the average mean blur rate (MBR), maximum MBR (Max-MBR), minimum MBR (Min-MBR), and area ratio of the blood stream (ARBS). As the pulse waveform parameters, we also calculated the skew, blowout score (BOS), blowout time (BOT), rising rate, falling rate, flow acceleration index (FAI), acceleration time index (ATI), resistivity index (RI), and beat strength over MBR (BOM). All parameters were compared between left and right eyes.

RESULTS

MBR-average, MBR-Max, MBR-Min, ARBS, skew, BOT, rising rate, falling rate, FAI, ATI, and ARBS did not differ significantly between the right and left eyes. The BOS in the right eyes was significantly lower than that of the left eyes, and the RI and BS in the right eyes were significantly higher than those of the left eyes. Similarly, for the whole of the ONH, the BOS in the tissue area (Tissue) and in the vessel area (Vessel) of the right eyes were significantly lower than those of the left eyes, and RI-Tissue, RI-Vessel, BOM-Tissue, and BOM-Vessel in the right eyes were significantly higher than those of the left eyes.

CONCLUSION

By using LSFG, we observed laterality of the BOS, RI, and BOM, all of which are pulse wave form parameters in the ONH.

Ocular microvascular damage in autoimmune rheumatic diseases: The pathophysiological role of the immune system

Pathological eye involvement represents a quite common finding in a broad spectrum of autoimmune rheumatic diseases (ARDs). Ocular signs, often occur as early manifestations in ARDs, ranging from symptoms related to the mild dry eye disease to sight-threatening pathologies, linked to the immune response against retinal and choroidal vessels. Retinovascular damage driven by markedly inflammatory reactivity need a prompt diagnosis and treatment. Immune-complexes formation, complement activation and antibody-mediated endothelial damage seem to play a key role, particularly, in microvascular damage and ocular symptoms, occurring in systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and Sjögren's syndrome (SS). Conversely, early alterations of retinal and choroidal vessels in the asymptomatic patient, often detectable coincidentally, might be indicators of widespread vascular injury in other connective tissue diseases. Particularly, endothelin-induced hypoperfusion and pathological peri-choroidal extracellular matrix deposition, might be responsible for the micro-architectural alterations and loss of capillaries detected in systemic sclerosis (SSc). Instead, interferon alpha-mediated microvascular rarefaction, combined with endothelial lesions caused by specific autoantibodies and immune-complexes, appear to play a significant role in retinal vasculopathy associated to inflammatory idiopathic myopathies (IIM). The immuno-pathophysiological mechanisms of ocular microcirculatory damage associated with the major ARDs will be discussed under the light of the most recent achievements.

Leukocyte-endothelial interactions within the ocular microcirculation in inflammation and infection

Leukocyte-endothelial interactions within the microvasculature represent a hallmark of inflammation regardless of whether the inflammation results from non-infectious or infectious triggers. In this review, we highlight features of leukocyte recruitment in ocular disease and postulate mechanisms by which the infiltrating cells may lead to the progression of the ocular inflammatory response, including cytokine and chemokine production, T cell or non-T cell responses. Additionally, ex-vivo and in vivo methods used to study the general features of the immune response are discussed, with a specific focus on intravital imaging, which allows real-time non-invasive examination of leukocyte-endothelial interactions in the ocular microvasculature. At the present time there are still significant gaps in our understanding of the process of leukocyte recruitment in vivo in different microvascular beds. Further studies using non-invasive imaging approaches, such as intravital microscopy, provide an opportunity to study dynamic tissue-specific leukocyte-endothelial interactions in vivo and identify novel targets for early intervention in the inflammatory process. This knowledge is essential to the rational use of therapeutics to resolve inflammation in ocular disease.