In the field of ophthalmology, we have comprehensively demonstrated that FABP4 is also present in vitreous fluid and that levels of FABP4 are significantly increased in patients with retinal vascular diseases (RVDs) such as proliferative diabetic retinopathy (PDR) [9] and retinal vein occlusion (RVO) [10], which are representative vision-threatening retinal complications of DM, HT and HL [11,12,13,14]. The gene discussed is FABP4; the disease is hematocrit.