Abstract
Purpose :
The suprachoroidal space (SCS), the virtual space between the sclera and the choroid, is a novel drug delivery route to the back of the eye. An in-office procedure has been developed utilizing the SCS MicroinjectorTM to penetrate the sclera and access the SCS. Suprachoroidal (SC) injection is first attempted with a 900 µm needle and then graduates to a 1100 µm needle when the space is not cannulated, likely due to scleral thickness variations. High myopia is known to correlate with decreased scleral thickness equatorially. This analysis evaluates the relationship between refraction (as an indicator of scleral thickness) and needle length for SC injection.
Methods :
Post hoc analyses were performed to assess the relationship between needle length for baseline injection and refraction. Baseline refractions were obtained and converted to spherical equivalents for 58 patients across 3 sites. Univariate and multivariate analyses were conducted with the biserial correlation and logistical regressions, respectively.
Results :
The mean spherical equivalents for baseline injections with the 900 and 1100 µm needles are -0.53 (n=42) and -0.67 (n=16), respectively, with no statistical difference. Moderate or high myopia (-3.0 Diopters) was observed in 8 out of 58 patients. Biserial correlation revealed no correlations between needle length and spherical equivalents for a wide range of variables for phakic patients. Multivariate analysis also revealed no statistical relationship between needle length and spherical equivalent.
Conclusions :
While these analyses are retrospective with relatively small sample size, refraction appeared to have little correlation with the needle length used for SC injections. This is supported by the literature that scleral thinning with myopia is more prominent along the anterior-posterior axis than around the circumference near the pars plana, where SC injections are administered. Taken together, this indicates that SC injections with the SCS Microinjector has the potential to reliably and repeatably deliver drugs for chorio-retinal diseases among a wide span of refractive values.
This is a 2020 ARVO Annual Meeting abstract.