Methods and devices for delivering therapeutic or diagnostic energy (e.g., light, ultrasound, ionizing radiation (e.g., x-ray), vibration, heat energy, etc.) into the eye. An energy emitting device is positioned on the eye and used to deliver energy into the eye. The device may be constructed to allow the subject's eyelids to open and close while the device is positioned on the eye. The device is useable for various energy based or energy-mediated therapies, including crosslinking of corneal collagen, light therapy, photodynamic therapy, photo-activation of drugs, etc.