Disclosed herein is a disposable cap for an eye imaging apparatus with an optical window and related methods. The disposable cap can comprise an optically transparent window cover, a ridge, a side wall and a locking element. The window cover can comprise a convex back surface to match a concave shape of the optical window. The ridge of the disposable cap can extend distally and radially outward from the window cover and the side wall can extend proximally and radially outwardly from the ridge. The locking element can comprise one or more radially inward projections and one or more radially outward releasing tabs. A disposable packaging shell of the disposable cap also disclosed. Disclosed herein is also a plug-in disposable system comprising the disposable cap and the disposable packaging shell, configured to enable the disposable cap to be attached to and detached from the eye imaging apparatus.