Choriocapillaris and choroidal thickness in all Leber hereditary optic neuropathy stages using swept source technology.

PURPOSE: The role of the choroid in Leber hereditary optic neuropathy (LHON) remains unclear. The literature is scarce, with conflicting results and lacks axial length measurements. Therefore, we aimed to analyse the choriocapillaris (CC) vessel density (VD) and choroidal thickness (ChT) in all stages of LHON using swept source (SS) technology and considering the possible influence of axial length on choroidal parameters. METHODS: This was a prospective cross-sectional observational study. A total of 119 eyes of 60 patients with molecularly confirmed LHON across all stages and 120 eyes of 60 control participants were included. We obtained the CC VD using optical coherence tomography angiography maps centred on the fovea. ChT was measured from the Bruch's membrane to the choroid-sclera interface in the macular and peripapillary regions. RESULTS: The CC VD was not significantly affected in any sector or average, except for a slight change in the superior region of chronic eyes (52.08 ± 1.62% vs. 53.50 ± 2.29%, p = 0.002). ChT demonstrated a trend towards decreased values in asymptomatic eyes and increased values in the symptomatic stages that failed to reach statistical significance in sectors corresponding to the papillomacular bundle except for the macular nasal inner sector of chronic eyes (281.10 ± 67.12 µm vs. 252.08 ± 70.55 µm, p = 0.045). No significant correlations were observed between visual acuity and CC VD or ChT. CONCLUSION: The CC VD remained stable across the LHON stages. Choroidal vasculature does not appear to play a role in LHON pathophysiology. Further research is needed on ChT as a potential biomarker of LHON.

Quantitative assessment of macular and circumpapillary retinal vessel density across all stages of Leber hereditary optic neuropathy using swept source optical coherence tomography angiography.

PURPOSE: To investigate the macular and circumpapillary retinal microvasculature across all stages of Leber hereditary optic neuropathy (LHON) using swept source optical coherence tomography angiography (OCTA). METHODS: This prospective, multicentre, cross-sectional, observational study analysed a total of 119 eyes of 60 patients with molecularly confirmed LHON across all stages and 120 eyes of 60 control subjects. Optical coherence tomography angiography maps centred on the fovea and optic disc were obtained to measure vessel densities (VDs) in the macular superficial (SCP) and deep (DCP) capillary plexuses, and the radial peripapillary capillary plexus (RPCP) respectively. RESULTS: In asymptomatic eyes, only the SCP showed significant changes on average (B coefficient = -0.72, 95% CI = -1.34 to -0.10, p = 0.022) or in sectors representing the papillomacular bundle (PMB) (B coefficient = -1.17, 95% CI = -2.23 to -0.11, p = 0.031). However, in chronic eyes, the greatest magnitude of change was found in the temporal sector of the RPCP (B coefficient = -12.36, 95% CI = -14.49 to -10.23, p < 0.001). The RPCP showed the strongest correlations with visual acuity (VA, logarithm of the minimum angle of resolution; R = -0.677, p < 0.001) and structural parameters (R = 0.747, p < 0.001). CONCLUSIONS: Retinal VD changes in the circumpapillary region of the PMB appear later than in the macula but end up being more profound and correlate better with VA and structural parameters. Further studies are needed to assess the clinical utility of retinal VDs as potential LHON biomarkers.

Swept source optical coherence tomography angiography in patients treated with hydroxychloroquine: correlation with morphological and functional tests.

PURPOSE: To evaluate swept source optical coherence tomography angiography (SS-OCTA) in patients treated with hydroxychloroquine (HCQ) for more than 5 years and to compare results with the tests currently recommended for screening of HCQ retinopathy. METHODS: In this controlled pilot study, consecutive patients treated with HCQ for more than 5 years underwent SS-OCTA, SS-OCT B-scan and en-face C-scan, fundus autofluorescence (FAF), 10-2 automated visual field (AVF) testing and multifocal electroretinography (mfERG). On SS-OCTA, evaluation of the retinal superficial capillary plexus, middle capillary plexus, and deep capillary plexus (DCP) and the choriocapillaris (CC) was obtained. RESULTS: We included 10 patients under HCQ treatment (20 eyes, mean age 38.91±11.73 years) and 18 healthy control patients (36 eyes, mean age 38.87±8.6 years). Mean duration of HCQ treatment was 10.0±3.25 (5-15) years and HCQ cumulative dose/body weight was 15.86±5.56 g/kg. The HCQ group showed a reduction of the vessel density in the 1 mm central, in the nasal and temporal subfields of DCP and in the 1 mm central subfield of CC, an increased foveal avascular zone in the three capillary plexuses, a greater frequency of CC flow voids and a reduced foveal choroidal thickness (p<0.05). Best-corrected visual acuity (BCVA), mfERG, SS-OCT B-scan and C-scan, AVF and FAF were normal in 20/20 eyes (100%). CONCLUSIONS: In patients treated with HCQ for more than 5 years, choroidal thinning and flow abnormalities at SS-OCTA in the retinal capillary plexuses and CC may be observed even if BCVA, FAF, mfERG, AVF and SS-OCT are normal.

QUANTITATIVE AND QUALITATIVE ANALYSIS OF THE THREE CAPILLARY PLEXUSES AND CHORIOCAPILLARIS IN PATIENTS WITH TYPE 1 AND TYPE 2 DIABETES MELLITUS WITHOUT CLINICAL SIGNS OF DIABETIC RETINOPATHY: A Prospective Pilot Study.

PURPOSE: To separately evaluate the three retinal capillary plexuses and the choriocapillaris in patients with diabetes mellitus (DM) Type 1 and Type 2, without clinical signs of diabetic retinopathy. METHODS: The study was prospective and cross-sectional. Only patients with age ≤55 years were included. We used a swept-source optical coherence tomography angiography device (Triton; Topcon, Tokyo, Japan) to obtain both quantitative and qualitative analysis of the retinal capillary plexuses (superficial capillary plexus; middle capillary plexus; and deep capillary plexus) and the choriocapillaris. RESULTS: We included 17 patients with DM Type 1 (age 34.52 ± 11.05 years, 29 eyes), 17 patients with DM Type 2 (age 48.76 ± 3.26 years, 32 eyes), and 23 healthy control subjects (age 41.82 ± 8.97 years, 43 eyes). When compared with controls, vessel density in the central 1 mm was reduced in both DM Type 1 and DM Type 2 groups in the superficial capillary plexus (P = 0.05 and P = 0.02, respectively), and in DM Type 2 in the deep capillary plexus (P = 0.03). Foveal avascular zone was increased in the middle capillary plexus and deep capillary plexus of DM Type 2 group compared with controls (P = 0.03 and P = 0.02, respectively). Choriocapillary voids were more frequent in DM Type 1 and DM Type 2 compared with controls (P = 0.003 and P < 0.001, respectively). CONCLUSION: Microvascular modifications are present in the three retinal capillary plexuses and the choriocapillaris in both DM Type 1 and DM Type 2 even in the absence of clinical signs of diabetic retinopathy.