Dr Moïse Tourabaly · Key points
The device projects rings of light onto the cornea. Their reflection draws closer together where the cornea is more curved; the software turns this into a colour map.
The reflection of the rings
The colour map
Regular astigmatism. Two equal, aligned lobes meeting at the centre: a pattern entirely compatible with refractive surgery.
Needs further investigation. Unequal or misaligned lobes may indicate irregular astigmatism or early keratoconus.
Suggestive of keratoconus. A localised bulge in the lower part of the cornea leads to further examination and then, if confirmed, to dedicated keratoconus follow-up.
It is always the ophthalmologist who decides, by cross-checking the map with the thickness of the cornea (pachymetry), the other measurements and the examination.
Educational diagram · Dr Moïse Tourabaly, ophthalmologist. Simulated maps: the actual colours and scale depend on the device. It does not replace a consultation.