Dr Moïse Tourabaly · Key points
A perfect eye would bring every ray together at a single point on the retina. No eye quite manages it: its optical imperfections, the aberrations, scatter the light slightly. Aberrometry measures them, all of them.
The measurement starts from here: a point of light, at night, would give a sharp point.
Lower order. Myopia, hyperopia and regular astigmatism: the bulk of the visual defect. The focus is shifted in a regular way; glasses, contact lenses and conventional refractive surgery bring it back onto the retina.
Higher order. Spherical aberration, coma, trefoil: subtler, they barely alter the acuity read on the letter chart, but they degrade the quality of vision when light is low: haloes, glare, night driving. Even with optimal correction.
Corneal aberrometry, performed at the practice, is calculated from the topography (the shape of both faces of the cornea). Total aberrometry, by wavefront, measures the whole eye, cornea and lens, on a dedicated device. No contact, a few seconds per eye. The resulting map explains night-time discomfort and can guide a customised laser treatment.
Educational diagram · Dr Moïse Tourabaly, ophthalmologist. It does not replace a consultation.