Smartphones are now used as Opthalmoscopes to record the image of the eye at ease. An Ophthalmoscope is used by a health professional to see inside the fundus of the eye and other structures. But they are not easy to use.
Dr. Andrea Russo, an ophthalmologist, devised the D-EYE, a smartphone lens attachment that turns a variety of smartphones into digital ophthalmoscopes. Light comes from the smartphone's LED, off-axis from the camera lens. A path of light from this LED delivers the light exactly coaxial to the camera using a combination of levers and beam splitters.
It gives a better visual of the pupil and eye. Once you see the red reflex from the eye, the D-EYE is correctly focused. You can increase the field of view by moving the phone/D-EYE closer to the eye, without changing the focus.
"D-EYE uses the principle of direct ophthalmology. It's like looking through a keyhole - the closer you are to the keyhole, the wider the field of view you have beyond it, said Dr. Russo.
Using the smartphone's auto focusing capabilities, refractive errors can be corrected to compensate between -10D myopia to +10D hyperopia. Even with undilated pupils, it's possible to scan the retina with a field of view of 5-8 degrees.
Optic disc with pupils as small as 2mm, can be viewed so the D-EYE can offer a rapid screening for glaucoma or hypertensive retinopathy for undilated pupils.