Corneal reshaping for myopia
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Corneal reshaping is a therapy to correct myopia by the use of contact lenses. Also known as orthokeratology and corneal refractive therapy, it has become a common procedure in temporarily reducing or removing myopia.

Advancement in corneal reshaping contact lens designs and materials had rendered it a more convenient choice over surgery or refractive correction for myopic cases. However, this therapy requires proper education about its implementation both for the practitioners and for patients to ensure maximum benefit and safety.

The corneal reshaping process

Corneal reshaping, also known as corneal refractive therapy or orthokeratology, was first implemented in the early 1960s. The original goal of corneal reshaping was to permanently change the shape of the cornea by wearing specialized contact lenses during sleep. Such contact lenses were made of high oxygen permeable materials and more advanced designs. The therapy involves central epithelial thinning and midperipheral epithelial and stromal thickening. Though it has broken new grounds, there is still a lot more research to be done in this field.

Effectiveness of corneal reshaping

There is still a lot of ground to be covered in the effectiveness of corneal reshaping in controlling myopia. When it started off, various research labs reported short lived and erratic results of corneal reshaping therapy. There were hardly any reports of significant achievements.

Three sets of tests conducted from the late-1970s to the mid-1980s, implemented spherical design (base curve steeper than secondary curve) contact lenses worn for waking hours only. It was applied on cases reporting a mean spherical equivalent refractive divergence of about –2.50D. The treatment time span ranged from 132 days to 17.7 months. All three researches reported a myopia reduction of less than 75% and recurrence of the previous syndromes after the discontinuation of the contact lens.

Hence, research in this field took a back seat until the mid-1990s, when the possibility of more advanced materials and designs brought hope. The new contact lenses allowed nighttime use and reported quicker and more noticeable results.

The latest studies have reported substantial results within the first month. Rapid correction of baseline refractive error has been reported through the first 24 to 72 hours and expected recovery over two weeks.

Advice from the prescribing eye care practitioner

Eye care practitioners should give users of conreal reshaping contact lenses extensive advice and information on their use. The advice can and should include:

  • To begin with, practitioners must inform their patients that the refractive therapy with corneal reshaping contact lenses ends the moment the patient stops using the lenses. They must also be cautioned that the lenses have not proved effective in slowing the development of myopia in children or adults.
  • Practitioners should provide product labeling information to their patients in brief and compelling written directives highlighted by simple graphic demonstrations.
  • Patients should be given emergency contact details of the practitioner.
  • Practitioners should seek precise approval and furnish detailed information to patients before they take up corneal reshaping therapy. This is done with a consent form and a pediatric assent form for corneal reshaping contact lens wear in chilren.

Side effects of corneal reshaping

There have been reports of various ill effects of the use of corneal reshaping contact lenses. They are as follows:

  • Reversible asymptomatic corneal pigmentation rings
  • Increase in higher order aberrations, particularly spherical aberration
  • Serious side effects like corneal ulcers or microbial keratitis

There have been alarming cases reported, especially in children who have been using corneal reshaping contact lenses for the control of myopia. Research that compares the effect of the use of corneal reshaping contact lens versus spectacles, report corneal reshaping contact lenses slow the axial growth of the eye 46% through a span of two years. However, there have been some gaps in this research and controversies remain about the frequency and prevalence of microbial keratitis as a consequence of corneal reshaping contact lens wear.

Safeguards against the side effects

For the user there are standard procedures to follow to avoid side effects with corneal reshaping lenses including:

  • Do not rinse or store your contact lenses in tap water.
  • Clean and disinfect your contact lenses every time you remove them from your eyes. Moreover, it should be done strictly according to the guidelines issued by the manufacturer.
  • Seek professional help if you suffer from sudden and persistent redness, discomfort or blurring of vision while using the lenses.
  • Visit your practitioner every six months to check your eyes and contact lenses, even if you have no complaints.
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