Both the central and peripheral retina contribute to myopia development in chicks.
OBJECTIVE
This study examined the contribution of the central and peripheral retina to the development of form deprivation myopia in chicks.


METHODS
Chicks were treated for 7 days either with centrally form-deprived (CFD) lenses of 2/4/6/8 mm diameter central diffuse zone, or a full size diffuser lens on their right eyes. The left eyes wore a full field plano lens. Axial dimensions and refractions were measured before and after 4 and 7 days of lens wear.


RESULTS
All eyes that had worn CFD lenses of 2/4/6/8 mm had significant changes in refractive errors (from -2.69 ± 0.40 D to -6.13 ± 0.76 D, p < 0.05), vitreous chamber depth (from 0.19 ± 0.04 mm to 0.56 ± 0.04 mm, p < 0.05) and axial length (from 0.42 ± 0.03 mm to 0.96 ± 0.04 mm, p < 0.05) during the experiment, except for the changes in refractive error (-2.81 ± 0.33 D, p = 0.053) and axial length (0.77 ± 0.04 mm, p = 0.050) in the 2 mm lens group after 7 days of lens wear. The myopic shift in the CFD lens wearing eyes was due primarily to an increase in vitreous chamber depth. Linear regression analysis showed that the changes of refractive error, vitreous chamber depth and axial length were positively correlated with the size of central form-deprived retina. Form depriving the central retina produced axial myopia even in the presence of clear peripheral vision.


CONCLUSIONS
The current study showed that both the central and peripheral retina contributes to myopia development in chicks. The amount of myopia induced increased linearly with the area of retina being form-deprived. It suggests that in terms of decoding optical input for growth, the area of retina being exposed to optical signals may be critical in determining eye growth.
State key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.|Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China.
Jian Chao
JC
Wang
Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China.
Rachel K M
RK
Chun
Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China.|Department of Ophthalmology, Renmin Hospital of Wuhan University, Wuhan, China.
Yun Y
YY
Zhou
Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China.
Bing
B
Zuo
Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China.
King Kit
KK
Li
State key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.|Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China.
Quan
Q
Liu
State key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.|Laboratory of Experimental Optometry, Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China.
Chi Ho
CH
To
D000818:Animals; D058452:Axial Length, Eye; D002645:Chickens; D004195:Disease Models, Animal; D009216:Myopia / Q000503:physiopathology*; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000503:physiopathology; D012683:Sensory Deprivation / Q000502:physiology; D014794:Visual Fields / Q000502:physiology*; D014822:Vitreous Body / Q000473:pathology
central retina; chick; emmetropisation; form deprivation myopia; periphery