UV-blocking spectacle lens protects against UV-induced decline of visual performance.
OBJECTIVE
Excessive exposure to sunlight may be a risk factor for ocular diseases and reduced visual performance. This study was designed to examine the ability of an ultraviolet (UV)-blocking spectacle lens to prevent visual acuity decline and ocular surface disorders in a mouse model of UVB-induced photokeratitis.


METHODS
Mice were divided into 4 groups (10 mice per group): (1) a blank control group (no exposure to UV radiation), (2) a UVB/no lens group (mice exposed to UVB rays, but without lens protection), (3) a UVB/UV400 group (mice exposed to UVB rays and protected using the CR-39™ spectacle lens [UV400 coating]), and (4) a UVB/photochromic group (mice exposed to UVB rays and protected using the CR-39™ spectacle lens [photochromic coating]). We investigated UVB-induced changes in visual acuity and in corneal smoothness, opacity, and lissamine green staining. We also evaluated the correlation between visual acuity decline and changes to the corneal surface parameters. Tissue sections were prepared and stained immunohistochemically to evaluate the structural integrity of the cornea and conjunctiva.


RESULTS
In blank controls, the cornea remained undamaged, whereas in UVB-exposed mice, the corneal surface was disrupted; this disruption significantly correlated with a concomitant decline in visual acuity. Both the UVB/UV400 and UVB/photochromic groups had sharper visual acuity and a healthier corneal surface than the UVB/no lens group. Eyes in both protected groups also showed better corneal and conjunctival structural integrity than unprotected eyes. Furthermore, there were fewer apoptotic cells and less polymorphonuclear leukocyte infiltration in corneas protected by the spectacle lenses.


CONCLUSIONS
The model established herein reliably determines the protective effect of UV-blocking ophthalmic biomaterials, because the in vivo protection against UV-induced ocular damage and visual acuity decline was easily defined.
Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, Taiwan ; School of Optometry, Chung Shan Medical University, Taichung, Taiwan ; Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan.
Jyh-Cheng
JC
Liou
Department of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
Mei-Ching
MC
Teng
Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, Taiwan ; School of Optometry, Chung Shan Medical University, Taichung, Taiwan.
Yun-Shan
YS
Tsai
Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, Taiwan ; School of Optometry, Chung Shan Medical University, Taichung, Taiwan.
En-Chieh
EC
Lin
Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, Taiwan ; School of Optometry, Chung Shan Medical University, Taichung, Taiwan.
Bo-Yie
BY
Chen
D000818:Animals; D003315:Cornea / Q000528:radiation effects; D065306:Corneal Injuries / Q000209:etiology / Q000517:prevention & control; D004195:Disease Models, Animal; D005135:Eye Protective Devices; D005139:Eyeglasses; D005260:Female; D006801:Humans; D007634:Keratitis / Q000209:etiology / Q000517:prevention & control; D051379:Mice; D008813:Mice, Inbred ICR; D014466:Ultraviolet Rays / Q000009:adverse effects*; D014792:Visual Acuity / Q000528:radiation effects*