Ortho C


According to Curtin (1985) and Doonan (1984), there is a relation between the bulging of the ciliary muscle and the excess tension of the oblique muscles which causes the elongated eye. Mutti et al. (2012) suggested that a potential treatment would be to loosen the ciliary muscle. But he is not aware of any method to achieve that.

Essentially, the ortho C lens relaxes the oblique muscles first. It is a plain lens with no prescription, and it is slightly flatter than the cornea. It is a flexible lens, so that it can “draw” against the cornea instead of attempting to flatten it as in ortho K. The cornea curvature does not change.

There is a neurological component in the treatment. The excess tension of the oblique muscles placed a ceiling on how much the lens can flatten for distant focusing (by causing the ciliary muscle to become tense). By removing the tension of the oblique muscles neurologically, it resets the correct neurological response. The tension of the ciliary muscle would relax which in turn would causes the lens to flatten more for distant focusing. It would reset Helmholtz’s theory (Yee, 2020).

In the second stage of the treatment, the relaxation of the ciliary muscle can also stimulate the eyeball to become less elongated. It would be the reverse of near-point stress. (Refer to the page near-point stress for more information.)

For now just focus on the mechanics of the lens--or the "contact lens draw". It will enhance your understanding of the neurological component of ortho C.

The video is an excerpt from a presentation I gave at Inside Optics, a professional education seminar for opticians in 2020.