A nexus letter, also referred to as an Independent Medical Opinion (IMO), is an official document used in the VA disability claims process, authored by a qualified medical professional. This letter offers a medical expert's opinion that establishes a "nexus," or link, between a veteran's current medical condition and their military service. It explains how specific events or exposures during service relate to the veteran's health issues.Nexus letters are particularly important for supporting service-connected disability claims, especially when the cause of the condition isn't clearly documented in military records or when conditions have deteriorated after service. For instance, if a veteran experiences worsening hearing loss following military service due to extended exposure to noise from aircraft, a nexus letter can help.A well-crafted nexus letter can greatly enhance a veteran's claim and improve their chances of receiving an accurate VA disability rating by providing strong evidence of the connection to their service.