RESUMO
Certain ocular conditions result from the non-physiological presence of intraocular particles, leading to visual impairment and potential long-term damage. This happens when the normally clear aqueous humor becomes less transparent, thus blocking the visual axis and by intraocular pressure elevation due to blockage of the trabecular meshwork, as seen in secondary open-angle glaucoma (SOAG). Some of these "particle-related pathologies" acquire ocular conditions like pigment dispersion syndrome, pseodoexfoliation and uveitis. Others are trauma-related, such as blood cell accumulation in hyphema. While medical and surgical treatments exist for SOAG, there is a notable absence of effective preventive measures. Consequently, the prevailing clinical approach predominantly adopts a "wait and see" strategy, wherein the focus lies on managing secondary complications and offers no treatment options for particulate matter disposal. We developed a new technique utilizing standing acoustic waves to trap and direct intraocular particles. By employing acoustic trapping at nodal regions and controlled movement of the acoustic transducer, we successfully directed these particles to specific locations within the angle. Here, we demonstrate control and movement of polystyrene (PS) particles to specific locations within an in vitro eye model, as well as blood cells in porcine eyes (ex vivo). The removal of particles from certain areas can facilitate the outflow of aqueous humor (AH) and help maintain optimal intraocular pressure (IOP) levels, resulting in a non-invasive tool for preventing secondary glaucoma. Furthermore, by controlling the location of trapped particles we can hasten the clearance of the AH and improve visual acuity and quality more effectively. This study represents a significant step towards the practical application of our technique in clinical use.
RESUMO
Retinal vein occlusion (RVO) results in ischemia followed by an inflammatory response. Both processes affect tissue temperature in opposite directions. Here, we evaluate the effect of RVO on the ocular surface temperature (OST) profile. Subjects with RVO were prospectively recruited. Healthy subjects without any ocular disease served as controls. The OST was determined using the Therm-App thermal imaging camera, and image processing software was employed to compute the mean temperature values of the medial canthus, lateral canthus, and cornea. We obtained thermographic images from 30 RVO subjects (30 eyes) and 148 controls (148 eyes). A univariate analysis found that eyes with RVO had significantly elevated OSTs compared to the controls (mean difference of 0.6 ± 0.3 Celsius, p < 0.05). However, this distinction between the groups lost statistical significance upon adjusting for possible confounders, including patient and environmental factors. These findings were confirmed with a post hoc case-control matched comparison. In conclusion, RVO does not seem to affect the OST. This might be due to the balance between inflammatory thermogenesis and heat constriction from ischemia in RVO. It is also possible that, in our cohort, the RVO pathophysiological processes involved were localized and did not extend to the anterior segment. Patient and environmental factors must be considered when interpreting the OST.
