Scleral Cross-Linking Using Riboflavin UVA Irradiation for the Prevention of Myopia Progression in a Guinea Pig Model: Blocked Axial Extension and Altered Scleral Microstructure.
OBJECTIVE
To develop methods of collagen cross-linking (CXL) in the sclera for the treatment of progressive myopia and to investigate the biomechanical and histological changes that occur in as a result.


METHODS
Twenty 14-day-old guinea pigs were divided into 3 groups: the cross-linking group (CL, n = 8), non cross-linking group (NCL, n = 8), and control group (n = 4). The scleras of the right eyes of the guinea pigs in the CL group were surgically exposed and riboflavin was dropped onto the irradiation zone for 20 seconds prior to ultraviolet-A (UVA) irradiation. The same procedure was conducted on the NCL group but without UVA irradiation. No procedure was conducted on the control group. The right eyes of the guinea pigs in the CL and NCL groups were then fitted with -10.00DS optics for six weeks. Retinoscopy and the axial lengths (AXL) were measured at baseline, and at the second, fourth and sixth weeks post-treatment in all three groups. All animal subjects were euthanized after the sixth week and then biomechanical and histopathological examinations of the scleras were conducted.


RESULTS
The mean AXL of the NCL group was longer than both the control and CL groups at six weeks (P = 0.001). The mean refractive error in the NCL group was statistically significantly more negative than both the control and the CL groups at six weeks (P = 0.001). The scleral collagen fiber arrangements of the CL and control groups were denser and more regularly distributed than the NCL group. Ultimate stress of the sclera was lowest in the NCL group, followed by the CL then the control group (P<0.05). Ultimate strain (%) of the sclera was lowest in the CL group followed by the NCL and then the control group (P<0.05).


CONCLUSIONS
Our study demonstrates that scleral CXL using riboflavin UVA irradiation effectively prevents the progression of myopia by increasing scleral biomechanical strength in a guinea pig model.
Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.|The Department of Pre-hospital Emergency, the First People's Hospital of Hefei, Anhui, China.
Shuai
S
Liu
Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.|Department of Clinical Laboratory, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
Shengjie
S
Li
Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.|Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.|Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
Bingjie
B
Wang
Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.|Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.|Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
Xiao
X
Lin
Infections department, the People's Hospital of Fuyang, Anhui Medical University, Anhui, China.
Yi
Y
Wu
Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.|Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.|Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
Hong
H
Liu
Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.|Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.|Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
Xiaomei
X
Qu
Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.|Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.|Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
Jinhui
J
Dai
Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.|Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.|Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
Xingtao
X
Zhou
Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.|Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.|Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
Hao
H
Zhou
D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects / Q000528:radiation effects; D003094:Collagen / Q000378:metabolism / Q000648:ultrastructure; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004195:Disease Models, Animal; D018450:Disease Progression; D004548:Elasticity / Q000187:drug effects / Q000528:radiation effects; D005260:Female; D006168:Guinea Pigs; D008297:Male; D008854:Microscopy, Electron; D047728:Myopia, Degenerative / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D017319:Photosensitizing Agents / Q000494:pharmacology; D012256:Riboflavin / Q000494:pharmacology*; D012590:Sclera / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects*; D014466:Ultraviolet Rays
D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin