A Study to Collect Data on the Use of Eylea in Babies Born Too Early Who Have a Condition of the Eye Where Blood Vessels Grow Abnormally in the Retina (Retinopathy of Prematurity)

This is an observational study to collect data from Japanese babies with retinopathy of prematurity (ROP) who will be treated with Eylea. In observational studies, only observations are made without specified advice or interventions. ROP is a condition that affects the eye and occurs only in babies who are born too early. Most cases of ROP are mild and get better without treatment, but more serious cases need to be treated in time. ROP happens when the blood vessels in the "retina" grow abnormally. The retina is the layer of tissue at the back of the eye that picks up light and sends messages to the brain. In babies with ROP, these abnormal blood vessels can leak. This causes damage to the retina and can sometimes move it out of place causing medical problems such as blindness. Eylea is received as an injection into the eye. It works by blocking a certain protein (VEGF) that can cause blood vessels in the retina to grow abnormally. Eylea is already available in Japan and is approved for doctors to prescribe to babies with ROP. The participants in this study are Japanese babies with ROP that their doctors decided to treat with Eylea before the start of this study. Babies with ROP that were already prescribed Eylea by their doctors may also be included. The main purpose of this study is to collect more data on how safe the treatment with Eylea is in babies with ROP under a real-world setting. Another purpose of this study is to collect more data on how well Eylea works in these participants. To see how safe Eylea is, the study doctors will collect all medical problems that the participants treated with Eylea have. These medical problems are called adverse events. Doctors keep track of all the adverse events that happen, even if they do not think that they might be related to the treatment. To see how well Eylea works, the study doctors will check the number of participants: * with no active ROP after starting treatment * where ROP came back up to 6 months after start of treatment In this study, the study doctor will: * collect past data of the participants from medical records * interview the participants * collect treatment-related data during routine visits. The study duration is 6 months with 3 planned visits. One visit will be at start of treatment, one at one month and one at 6 months after start of treatment. All data required for this study will be collected during routine visits. Besides this data collection, no further tests or examinations are planned in this study.