Especially with corneal scarring, the aberrations are out of range of what the aberrometer can measure. When the amount of HOAs is great, which pertains to most cases of keratoconus, an aberrometer often cannot obtain a measurement. If glasses can fix higher order aberrations in keratoconus, why don’t they work? Despite nearly $80 million in venture capital funding, Ophthonix closed abruptly due to market failure. The results underwhelmed with outcomes indistinguishable from normal eyeglasses. Shortly after commercialization, I prescribed iZon wavefront-guided glasses for several of my mild keratoconus patients. Their Z-View aberrometer measured these aberrations, and a special laser altered the light-bending characteristics of a special polymer within the iZon lenses on a point-to-point basis. In the mid-2000’s, the now defunct start-up, Ophthonix, developed wavefront-guided iZon eyeglass lenses intended to correct both lower and higher order aberrations. They were used for laser vision correction candidates. Additionally, eye doctors never used PreVue lenses to treat keratoconus. Eye doctors no longer used PreVue lenses since custom laser vision correction has advanced beyond needing to create these simulations.

PreVue lenses were fabricated by first using an instrument called a wavefront aberrometer, to measure both lower and higher order aberrations before the excimer laser would cut the PreVue lens.

Yes, special eyeglass lenses can correct HOAs that characterize keratoconus and it has already been done! In the early 2000s, the excimer laser manufacturer VISX produced PreVue ophthalmic lenses to simulate the best-case scenario of their laser vision correction for patients without keratoconus when higher and lower order aberrations were fixed. Can eyeglasses correct higher order aberrations? Many patients with keratoconus can enjoy rigid surface scleral contact lenses for unsurpassed clear vision with the stability and comfort approaching a soft disposable contact lens.

In keratoconus, rigid surface contact lenses are the mainstay to reduce the lower and higher order aberrations. The kind of HOAs especially common to keratoconus is called coma, because it tends to smear a point of light into a comet shape. Patients with keratoconus usually have lots of lower and higher order aberrations, caused by their distorted corneas. They go by names like spherical aberration, coma, trefoil, tetrafoil, secondary astigmatism, and so forth. Traditional glasses and soft contact lenses do not correct HOAs. In the past, doctors name these “irregular astigmatism”. Higher order aberrations (HOAs) are complex and asymmetrical. Eyeglass lens correcting lower and higher order aberrations

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