Clinical relevance: Given the association of scleral characteristics with many ophthalmological diseases, there is an important need to measure the anterior scleral thickness (AST). Background: This study examined the AST by swept-source optical coherence tomography (SS-OCT) in a large healthy population, assessing also the reproducibility of AST measurements and the correlation with different parameters. Methods: Cross-sectional study in 605 eyes of 605 subjects. AST measurements were made in the temporal and nasal quadrants at 1 (AST1) and 3 mm (AST3) from the scleral spur using SS-OCT. These dimensions were then assessed for associations in a multivariate model with the factors age, sex, refractive error, conjunctival-Tenon capsule thickness (CTT), anterior chamber angle (ACA), intraocular pressure (IOP), iris thickness (IT), limbus-sulcus distance (LSD), and ciliary muscle thickness (CMT). The reproducibility of the AST measurements was determined in 30 of the participants. Results: The mean age was 42.6 ± 17.3 years (range 5 to 86 years). The following means were recorded: AST1 was 522.3 ± 65.7 µm (355 to 761) and 558.4 ± 71.5 µm (357 to 889); AST2 was 513.3 ± 67.3 µm (343 to 732) and 574.4 ± 71.6 µm (389 to 789), and AST3 548.8 ± 71.9 µm (356 to 762) and 590.1 ± 76.6 µm (414 to 873) in the temporal and nasal quadrants respectively, being thicker the nasal quadrant (all p < 0.001). A positive correlation was detected between AST and age, sex, temporal ACA and LSD (all p ≤ 0.043), being negative the correlation with CMT (p ≤ 0.044). No correlation was observed between AST measurements and refractive error, CTT and IT (p ≥ 0.064). The reproducibility of AST measurements was excellent (intraclass correlation coefficient ≥0.951). Conclusions: SS-OCT allows for in vivo AST measurements. Our data contained a wide range of measurements, showing an association between AST and age, sex, ACA, LSD and CMT.

Purpose: To assess the reproducibility of swept-source optical coherence tomography angiography (SS-OCTA) for macular and optic nerve head (ONH) vessel density (VD). Methods: Cross-sectional study using the Triton OCTA (Topcon, Tokyo, Japan), for VD (%) measurements in 40 eyes of 40 healthy subjects on two 6 × 6 mm scans of the macula and ONH across five subfields (central, superior, inferior, temporal, and nasal) at different segmentation levels: superficial capillary plexus (SCP), deep capillary plexus (DCP), outer retina, and choriocapillaris. Reproducibility values were summarized as intraclass correlation coefficients (ICCs) and coefficients of variations (CV). Results: ICCs for the macular VD measurements in the central zone were 0.874, 0.770, 0.575, 0.718 at the levels SCP, DCP, outer retina, and choriocapillaris, respectively, while worse ICCs were obtained for the parafoveal subfields (ICC ⩽ 0.589); CVs were 2.8%–6.7%. The reproducibility of the ONH superficial VD was ICC = 0.941 for the papillary region and was ICC = 0.499–0.853 for the peripapillary zone; CVs ranged from 4.8% to 17%. Peripapillary VD showed an ICC = 0.533–0.770 in the DCP layer, and 0.572–0.828 in the choriocapillaris. Lowest VD were obtained for the macular SCP and DCP (23% and 22%, respectively), in the foveal zone, while greatest VD were recorded in the nasal and temporal peripapillary subfields at the level of the choriocapillaris (both 68%). Conclusions: The new SS-OCTA software served to quantify macular and ONH VD with a reproducibility that was good in the central zones (foveal and papillary, respectively) and moderate in the peripheral zones (parafoveal and peripapillary).

To predict and compare the hypotensive efficacy of three minimally-invasive glaucoma surgery (MIGS) implants through a numerical model. Post-implant hypotensive efficacy was evaluated by using a numerical model and a computational fluid dynamics simulation. Three different devices were compared: the XEN 45 stent (tube diameter, 45 μm), the XEN 63 stent (63 μm) and the PreserFlo microshunt (70 μm). The influence of the filtration bleb pressure (Bp) and tube diameter, length, and position within the anterior chamber (AC) on intraocular pressure (IOP) were evaluated. Using baseline IOPs of 25, 30 and 50 mmHg, respectively, the corresponding computed post-implant IOPs for each device were as follows: XEN 45: 17 mmHg (29% decrease), 19 mmHg (45%) and 20 mmHg (59%) respectively; XEN 63: 13 mmHg (48%), 13 mmHg (62%), and 13 mmHg (73%); PreserFlo: 12 mmHg (59%), 13 mmHg (73%) and 13 mmHg (73%). At a baseline IOP of 35 mmHg with an increase in the outflow resistance within the Bp from 5 to 17 mmHg, the hypotensive efficacy for each device was reduced as follows: XEN45: 54% to 37%; XEN 63: 74% to 46%; and PreserFlo: 75% to 47%. The length and the position of the tube in the AC had only a minimal (non-significant) effect on IOP (<0.1 mmHg). This hydrodynamic/numerical model showed that implant diameter and bleb pressure are the two most pertinent determinants of hypotensive efficacy. In distinction, tube length and position in the AC do not significantly influence IOP.