Conjunctival microvascular hemodynamics following vaso-occlusive crisis in sickle cell disease

Conjunctival microcirculation in ocular and systemic microvascular disease

The conjunctival microcirculation is an accessible complex network of micro vessels whose quantitative assessment can reveal microvascular haemodynamic properties. Currently, algorithms for the measurement of conjunctival haemodynamics use either manual or semi-automated systems, which may provide insight into overall conjunctival health, as well as in ocular and systemic disease. These algorithms include functional slit-lamp biomicroscopy, laser doppler flowmetry, optical coherence tomography angiography, orthogonal polarized spectral imaging, computer-assisted intravitral microscopy, diffuse reflectance spectroscopy and corneal confocal microscopy. Furthermore, several studies have demonstrated a relationship between conjunctival microcirculatory haemodynamics and many diseases such as dry eye disease, Alzheimer's disease, diabetes, hypertension, sepsis, coronary microvascular disease, and sickle cell anaemia. This review aims to describe conjunctival microcirculation, its characteristics, and techniques for its measurement, as well as the association between conjunctival microcirculation and microvascular abnormalities in disease states.

Conjunctival optical coherence tomography angiography imaging in sickle cell maculopathy

Purpose

To compare conjunctival and macular manifestations of sickle cell anemia using optical coherence tomography angiography (OCTA).

Observations

OCTA imaging of the macula in two patients with HbSS and HbSC revealed areas of decreased vascular density, more prominent in the deep capillary plexus than in the superficial capillary plexus. Conjunctival OCTA of both affected patients revealed areas of reduced vascular density corresponding to the vascular abnormalities observed on slit lamp examination and prominent conjunctival flow voids when compared to an unaffected control.

Conclusionsand Importance

OCTA allows for high resolution visualization of conjunctival findings present in sickle cell patients with macular vascular flow voids. Further studies are needed to explore the utility of conjunctival OCTA and the relationship between conjunctival and macular perfusion and systemic hemoglobinopathy.

Conjunctival and pulmonary hemodynamic properties in sickle cell disease subjects with and without pulmonary hypertension

Conjunctival microvascular hemodynamic alterations were reported for the first time in sickle cell subjects with and without pulmonary hypertension. Assessment of the conjunctival microcirculation using noninvasive imaging may improve understanding of microvascular hemodynamic alterations that occur due to pulmonary hypertension in sickle cell disease.