- Correspondence to Dr Guoying Mu, Department of Ophthalmology, Provincial Hospital affiliated to Shandong University, No. 324, Jing 5 Road, Ji'nan City, Shandong Province, P. R. China, 250021;
- Received August 17, 2012
- Revised November 27, 2012
- Accepted January 3, 2013
- First published January 26, 2013.
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