The Navy standards will most likely be identical to the RAF, however the Navy do their best to get aircrew through the medicals, where as the RAF just tend to turn people down outright(2 mates turned down by RAF, RN were willing to investigate further and took them on). Eyesight is critical on joining, and colour blindness, especially red/green, is critical as you use it when flying approaches in some circumstances (PAPIs), and also needed to drive ships. No harm is asking though, don't ask = don't get.