Assessment of Full-Eye Response to Osmotic Stress in Mouse Model In Vivo Using Optical Coherence Tomography

Abstract

NaCl based solutions were applied as osmotic stress agents to alter the hydration state of the mouse eye. Full-eye responses to these osmotic challenges were monitored in vivo using a custom-built optical coherence tomography (OCT) with an extended imaging range of 12.38 mm. Dynamic changes in the mouse eye were quantified based on the OCT images using several parameters, including the central corneal thickness (CCT), the anterior chamber depth (ACD), the crystalline lens thickness (LT), the cornea-retina distance (CRD), the iris curvature (IC), and the lens scattering intensity (LSI). Apparent but reversible changes in the morphology of almost all the ocular components and the light transparency of the lens are exhibited. Particularly, the ocular dehydration induced by the hypertonic challenges resulted in a closing of the iridocorneal angle and an opacification of the lens. Our results indicated that the ocular hydration is an important physiological process which might be correlated with various ocular disorders, such as dry eye, cataract, and angle-closure glaucoma, and would affect the biometry and imaging of the eye. OCT uniquely enables the comprehensive study of the dynamic full-eye responses to the ocular hydration in vivo.

Reduced humidity experienced by mice in vivo coincides with reduced outflow facility measured ex vivo

“…Decreased humidity, possibly in combination with cold-stress (as the majority of mice in this study were likely cold-stressed), may also lead to dehydration, changes in fluid intake (Nicolaus et al, 2016) and reduced blood pressure, which may affect IOP and ocular physiology (Sherwin et al, 2015). Osmotic perturbation may also affect the anterior chamber angle in mice (Ni et al, 2015), which could affect outflow facility. Alternatively, low values of relative humidity and/or temperature may lead to elevated corticosterone or other stress hormones (Gong et al, 2015) that may contribute to reduced outflow facility (Clark and Wordinger, 2009;Overby et al, 2014b;Overby and Clark, 2015) that persists after death.…”

A Head-Mounted Spectacle Frame for the Study of Mouse Lens-Induced Myopia

“…Male C57BL6J mice aged postnatal 28 days (P28) underwent baseline retinoscopy refraction and axial length measurement using a custom-built optical coherence tomography (OCT), which has been detailed in [ 19 , 20 ] ( Figure 4 ). Two groups were set in the current study.…”

Angular compounding by full-channel B-scan modulation encoding for optical coherence tomography speckle reduction

“…1 It has found a wide range of applications in scientific research and clinics. 2,3 Like other imaging techniques involving coherence detection such as ultrasound, OCT speckle, caused by coherent addition of many small waves with a random phase and amplitude from randomly placed subresolution scatters, degrades the image quality and limits the identification of detailed structural features that could be crucial for distinguishing normal from diseased tissues. 4,5 Thus, effective methods of suppressing speckle noise are desired for facilitating the interpretation of OCT images.…”