Abstract
Purpose: :
The mouse has increasingly become the preferred animal model in ophthalmic research. For this reason, there is a need for enhancing our understanding of this eye to validate its use in different experimental settings. The purpose of this study was to determine the total ocular transmittance in the ultraviolet radiation (UVR) waveband and the relative contribution by the cornea and crystalline lens to this transmittance curve.
Methods: :
Mouse eyes were excised immediately after euthanization and placed under a 0.2 mm diameter detecting fiber optic illuminated by an Oceans Optics deuterium/halogen source (DT-MINI-2-GS). A small 1mm scleral hole was cut at the posterior pole to allow assessment of the whole eye UVR transmittance. The cornea and the lens were subsequently dissected out and transmittance measurements were carried out on each tissue separately. Data were recorded and analyzed with an Ocean Optics spectrometer (USB4000) coupled through the sample ocular tissues to the light source.
Results: :
The data showed that the mouse cornea and lens transmit UVR down to approximately 280 nm and 310 nm respectively. 50% UVR absorption is achieved at approximately 330um and 375 um by the cornea and the crystalline lens respectively. The combined transmittance spectra of the cornea and the lens compared well with the total UVR transmittance for the whole eye.
Conclusions: :
The good correlation between total ocular UVR transmittance and the sum of the individually measured components supported the validity of our findings. This experiment demonstrated that the mouse corneal UVR transmittance had a cut off similar to the human cornea. The mouse crystalline lens, in contrast, had a cut off (310 nm) in the UV spectrum which is radically different compared to the approximately 390 nm cut off for the human lens. Unlike the human, who have retinas relatively insensitive to UVR, the increased UVR transmittance in the mouse eye may serve its vision, since the mouse has a cone photopigment peaking at approximately 350 nm. It is concluded that the mouse is not an ideal model for the human eye in experiments involving UVR.
Keywords: optical properties • radiation damage: light/UV