Ascertainment of Cases and Controls

All patients who met the discharge diagnosis on the first page of the medical record system of Guangzhou First people’s Hospital and met the conditions of SAA (disease Code: D61.905) and HSCT (disease Code: Z94.800) were identified. CMVR was diagnosed according to typical ophthalmological signs judged by an experienced ophthalmologist using fundus pre-set lens with fully dilated pupils. For atypical presentation, the diagnosis of CMVR was supported by CMV load documented in aqueous humor by real-time quantitative polymerase chain reaction (PCR) analysis (Ljungman et al., 2017). There are three main fundus presentations of CMVR. The granular form is characterized by whitish granular lesions, often starting at the retinal periphery. The hemorrhagic/edematous form is more aggressive, which can rapidly lead to extensive yellowish foci of retinal necrosis intermingled with retinal hemorrhages. The frosted branch angiitis form is manifested by an occlusive retinal vasculitis with exuberant whitening of the vessel wall, as if it were frozen (Vadlapudi et al., 2012). Non-CMVR controls were matched to CMVR cases by a ratio of 4:1 using frequency matching on age and gender. The following age subgroups were used for matching: 15–25, 26–35, 36–45, and 46–50 years. A list of numbers computer-generated by a research member (Jinpeng Cao) was used to match the controls.