An optical imaging system includes a first lens system housed in a body of a mobile telecommunication device, the first lens system having a first optical axis, a first entrance pupil fixed in space in a reference plane associated with said body, and a first focal length； and an optical telescope providing a diffraction-limited imaging within a spectral range from at least 486 nm to at least 656 nm. The optical imaging system is configured to image, when the optical telescope is inserted between the first lens system and an entrance pupil of a visual system of an eye (EPE), the EPE onto the first entrance pupil and vice versa with a substantially unit magnification.
