Correlation between Retinal Vascularization and Disease Aggressiveness in Amyotrophic Lateral Sclerosis

Abstract

Abnormalities in retinal vascularization and neural density have been found in many neurodegenerative diseases; however, conflicting results are described in Amyotrophic Lateral Sclerosis (ALS). The aim of the present study was, therefore, to systematically analyze retinal layers and vascularization by means of spectral-domain (SD-OCT) and optical coherence tomography angiography (OCT-A) in ALS patients. We enrolled 48 ALS patients and 45 healthy controls. ALS patients were divided into three groups: slow progressors (n = 10), intermediate progressors (n = 24) and fast progressors (n = 14), according to the disease progression rate. For SD-OCT, we evaluated the Subfoveal choroidal thickness (SFCT), ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL). Regarding the OCT-A, we assessed the vessel density (VD) in superficial and deep capillary plexuses, radial peripapillary capillary plexus, choriocapillary and the foveal avascular zone (FAZ) area. SD-OCT exam did not show any significant differences in GCC and RNFL thickness between patients and controls and among the three ALS groups. The SFCT was statistically greater in patients compared with controls (357.95 ± 55.15 µm vs. 301.3 ± 55.80 µm, p < 0.001); interestingly, the SFCT was thicker in patients with slow and intermediate disease progression than in those with fast disease progression (394.45 ± 53.73 µm vs. 393.09 ± 42.17 µm vs. 267.71 ± 56.24 µm, p < 0.001). OCT-A did not reveal any significant results. Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-r) and disease duration did not correlate with any of the OCT parameters, except for SFCT with ALSFRS-r (r = 0.753, p = 0.024). This study demonstrated the possible association between choroidal thickness and disease activity in ALS. OCT could be a useful biomarker in the management of the disease.

Keywords: ALS; OCT; angiography; biomarker; choroid; disease progression; eye; inflammation; retinal nerve fiber layer; vascular.

Figure 1

Spectral domain optical coherence tomography (SD-OCT) images from a healthy subject’s right eye (male, 58 years) with normal thicknesses of ganglion cell complex (GCC) (A) and retinal nerve fiber layer (RNFL) (B). The OCT B-scan shows normal retinal and choroidal thickness (C). Patient’s right eye (female, 60 years) affected by amyotrophic lateral sclerosis (ALS) with slow disease progression. SD-OCT shows normal GCC and RNFL thickness (A1,B1). The OCT B-scan shows normal retinal thickness and a thicker choroid (C1). Patient’s right eye (female, 61 years) affected by ALS with intermediate disease progression. SD-OCT shows normal GCC and RNFL thickness (A2,B2). The OCT B-scan shows normal retinal thickness and an increased choroidal thickness (C2). The bottom row reveals a patient’s left eye (female, 57 years) affected by ALS with fast disease progression. SD-OCT shows normal GCC and RNFL thickness (A3,B3). The OCT B-scan shows normal retinal and a thinner choroid (C3).

Figure 2

OCT-A from a healthy subject’s right eye (male, 58 years) shows normal vasculature texture in macular region (retinal superficial, deep capillary plexuses and in coriocapillary) and in papillary region (A–C,E). The foveal avascular zone (FAZ) area shows a normal size (D). The second row shows the patient’s right eye (female, 60 years) affected by amyotrophic lateral sclerosis (ALS) with slow disease progression. OCT-A images reveal absence of abnormalities in retinal and choriocapillary vascular plexuses in macular and papillary regions (A1,B1,C1,E1). The FAZ shows a normal area (D1). The third row shows a patient’s left eye (female, 61 years) affected by ALS with intermediate disease progression. OCT-A reveals absence of abnormalities in retinal and choriocapillary vascular plexuses in macular and papillary regions (A2,B2,C2,E2). The FAZ shows a normal area (D2). The bottom row reveals the patient’s left eye (female, 57 years) affected by ALS with fast disease progression. OCT-A images show normal retinal and choriocapillary vascular plexuses in macular and papillary regions (A3,B3,C3,E3). The FAZ shows a normal area (D3).