en Ophtalmology Ophtalmology Original Article Original Article <span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="color:#0000ff;"><em><strong>Background:</strong></em></span> Retinopathy of prematurity (ROP) is a vasoproliferative retinal disease in premature infants that causes lifetime visual impairment and blindness in the early ages. In this study, we investigated the differences in the values of clinical laboratory parameters between different ROP and its remission/progression statuses regarding stages and zones.<br> <span style="color:#0000ff;"><em><strong>Methods:</strong> </em></span>This historical cohort study includes 828 infants divided into two groups after the first examination containing ROP infants and controls. The biochemical and hematological parameters of the two groups have been collected from the patient&rsquo;s history.<br> <span style="color:#0000ff;"><em><strong>Results:</strong></em></span> In infants with ROP, the hematopoiesis-related parameters, including the mean level of hemoglobin, total bilirubin, potassium, calcium were significantly less than controls (<em>P =0.039, P =0.001, P =0.001, </em>and<em> P=0.046,</em> respectively). The percentages of reticulocyte and the levels of BUN in ROP patients were significantly higher than in normal infants (<em>P=0.015 </em>and<em> p <0.001,</em> respectively). Moreover, the levels of hemoglobin and BUN were significantly different in the different zones of ROP (<em>P=0.017</em> and <em>P=0.001</em>, respectively). Also, higher hemoglobin levels, total bilirubin, and CRP were observed in the reduced stages of ROP (<em>P=0.041</em>, <em>P=0.045,</em> and <em>P=0.039</em>, respectively).<br> <span style="color:#0000ff;"><em><strong>Conclusion:</strong></em></span> Laboratory parameters are different in different stages, zones and remission/progression ROP infants.</span></span> Retinopathy of prematurity, Prognosis, Laboratory parameters, Hematologic parameters, Biochemical parameters. 385 392 http://caspjim.com/browse.php?a_code=A-10-2197-2&slc_lang=en&sid=1 Seyed Ahmad Rasoulinejad Seyedahmadrasoulinejad@gmail.com 100319475328460036538 100319475328460036538 Yes Department of Ophthalmology, Ayatollah Rouhani Hospital, Babol University of Medical Sciences, Babol, Iran Faezeh Maroufi matataf4@gmail.com 100319475328460036539 100319475328460036539 No Department of Medical Laboratory Sciences, Faculty of Allied Medicine, Qazvin University of Medical Sciences, Qazvin, Iran Ahad Alizadeh St.Alizadeh@gmail.com 100319475328460036540 100319475328460036540 No Metabolic Diseases Research Center, Qazvin University of Medical Sciences, Qazvin, Iran