Radial keratotomy
Radial keratotomy is a refractive surgery procedure where the surgeon makes a spoke-like pattern of incisions into the cornea to modify its shape. This early surgical option for myopia has been largely superseded by LASIK and other similar procedures. LASIK is absolutely contraindicated in keratoconus and other corneal thinning conditions as removal of corneal stromal tissue will further damage an already thin and weak cornea. For similar reasons, radial keratotomy has also generally not been used for people with keratoconus. Prognosis
Patients with keratoconus typically present initially with mild astigmatism and myopia, commonly at the onset of puberty, and are diagnosed by the late teenage years or early 20s. The disease can, however, present or progress at any age; in rare cases, keratoconus can present in children or not until later adulthood. A diagnosis of the disease at an early age may indicate a greater risk of severity in later life. Patients vision will seem to fluctuate over a period of months, driving them to change lens prescriptions frequently, but as the condition worsens, contact lenses are required in the majority of cases. The course of the disorder can be quite variable, with some patients remaining stable for years or indefinitely, while others progress rapidly or experience occasional exacerbations over a long and otherwise steady course. Most commonly, keratoconus progresses for a period of 10 to 20 years before the course of the disease generally ceases in the third and fourth decades of life.
Cevimeline (trade name Evoxac) is a synthetic analog of the natural alkaloid muscarine with a particular agonistic effect on M1 and M3 receptors. It is used in the treatment of dry mouth and Sjögrens syndrome. Medical uses
Cevimeline is used in the treatment of xerostomia (dry mouth), and Sjögrens syndrome. It increases the production of saliva. Side effects
Known side effects include nausea, vomiting, diarrhea, excessive sweating, rash, headache, runny nose, cough, drowsiness, hot flashes, blurred vision, and difficulty sleeping.Contraindications include asthma and angle closure glaucoma. Mechanism of action
Cevimeline is a cholinergic agonist. It has a particular effect on M1 and M3 receptors. By activating the M3 receptors of the parasympathetic nervous system, cevimeline stimulates secretion by the salivary glands, thereby alleviating dry mouth. See also
Pilocarpine — a similar parasympathomimetic medication for dry mouth (xerostomia)
Bethanechol — a similar muscarinic parasympathomimetic with longer-lasting effect

References
External links
Evoxac (cevimeline HCl hydrate capsules) Full Prescribing Information