Longitudinal Study of Optic Disk Perfusion and Retinal Structure in Leber's Hereditary Optic Neuropathy

Vascular Changes in the Macula of Patients after Previous Episodes of Vision Loss Due to Leber Hereditary Optic Neuropathy and Non-Arteritic Ischemic Optic Neuropathy

PURPOSE

to assess the vasculature and thickness of the macula using OCT-A in patients who had experienced a previous episode of Leber hereditary optic neuropathy (LHON) or non-arteritic anterior ischemic optic neuropathy (NA-AION).

METHODS

twelve eyes with chronic LHON and ten eyes with chronic NA-AION and eight NA-AION fellow eyes were examined using OCT-A. The vessel density was measured in the superficial and deep plexus of the retina. Moreover, the full and inner thicknesses of the retina were assessed.

RESULTS

There were significant differences in all sectors between the groups in regard to the superficial vessel density and the inner and full thicknesses of the retina. The nasal sector of the macular superficial vessel density was affected more in LHON than in NA-AION; the same with the temporal sector of the retinal thickness. There were no significant differences between the groups in the deep vessel plexus. There were no significant differences between the vasculature of the inferior and superior hemifields of the macula in all groups and no correlation with the visual function.

CONCLUSIONS

The superficial perfusion and structure of the macula assessed with OCT-A are affected both in chronic LHON and NA-AION, but more in LHON eyes, especially in the nasal and temporal sectors.

Acute Increase in Ocular Microcirculation Blood Flow Upon Cholesterol Removal. The Eyes Are the Window of the Heart

BACKGROUND

Lipoprotein apheresis acutely increases coronary microvascular blood flow. However, measurement techniques are time-consuming, costly, and invasive. The ocular vasculature may be an appropriate surrogate and an easily accessible window to investigate the microcirculation. Recent advances in ocular imaging techniques enable quick, noninvasive quantification of ocular microcirculation blood flow. The insights from these techniques represent a significant opportunity to study the short-term changes in optic disk blood flow after lipoprotein apheresis for inherited hypercholesterolemia.

METHODS

This study was performed at the Italian Reference Center for Inherited Dyslipidemias in Tuscany. The study sample was comprised of 22 patients with inherited hypercholesterolemia who were previously studied for coronary microcirculation. Laser speckle flowgraphy (LSFG) was used to measure optic disk blood flow before and after lipoprotein apheresis. The main outcomes measures were average tissue blood flow (referred to as mean tissue) and arteriolar/venular average blood flow (referred to as mean vessel). Eyes were divided into 2 groups based on pre-lipoprotein apheresis optic disk blood flow values. P < .05 was considered statistically significant.

RESULTS

After each lipoprotein apheresis treatment resulting in the reduction of plasma lipids, there was a concurrent increase in all optic disk microcirculatory parameters. The increase was statistically significant in eyes with lower pre-apheresis optic disk blood flow values (mean tissue +7.0%, P < .005; mean vessel +7.2%, P < .05).

CONCLUSIONS

A single lipoprotein apheresis session resulted in a statistically significant short-term increase in optic disk blood flow. These findings together with previous coronary microcirculation data suggest a similar ocular and coronary blood flow response to lipoprotein apheresis. Ocular microcirculation may represent a versatile biomarker for evaluating systemic microcirculatory health, including coronary microcirculation. Hence, it is plausible that plasma lipoprotein levels may influence optic disk blood flow.