1 Department of Ophthalmology, United Christian Hospital, Kowloon East Cluster, 130 Hip Wo Street, Kwun Tong, Kowloon, Hong Kong SAR.
2 Department of Ophthalmology, Tseung Kwan O Hospital, Kowloon East Cluster, 2 Po Ning Path, Tseung Kwan O, Hong Kong SAR.
3 Department of Ophthalmology, United Christian Hospital, Kowloon East Cluster, 130 Hip Wo Street, Kwun Tong, Kowloon, Hong Kong SAR. kennethli@rcsed.ac.uk.
4 Department of Ophthalmology, Tseung Kwan O Hospital, Kowloon East Cluster, 2 Po Ning Path, Tseung Kwan O, Hong Kong SAR. kennethli@rcsed.ac.uk.