Nonlinear Optical Photodynamic Therapy of the Cornea for Treatment of Low Refractive Errors

Tech ID: 27633 / UC Case 2017-573-0

Brief Description

Inventors at UC Irvine have developed an apparatus and method using nonlinear optical photodynamic therapy (NLO-PDT) for modifying corneal shape and treating progressive corneal astigmatism and refractive errors. The selectively focused femtosecond-near infrared laser light and apparatus improves upon existing methods by providing rapid (< 1min) corneal treatment that minimizes unwanted cellular damage to the eye through precise lateral and axial treatment to the cornea.

Full Description

Progressive and irregular changes in corneal shape known as ectasia often lead to high levels of myopia (near-sightedness) and astigmatism. During the last 20 years, LASIK has become the standard of care for the correction of refractive disorders.  LASIK procedure works well for 2 to 10 D refractive corrections, the risk associated with its invasiveness prevents the extensive use of LASIK in the 0 to 2 D range.  A low risk, noninvasive procedure is needed for achieving safe refractive corrections in the 0 to 2 D range.

Inventors at UC Irvine developed an apparatus and method for collagen crosslinking that does not use UV A light, and delivers highly localized photoactivation of the photosensitizing agent using nonlinear photodynamic therapy (NLO-PDT). The two-photon near-infrared laser rapidly generates free radicals in spatially controlled corneal regions that minimize cellular damage, making the procedure safer for patients.  Cross linking changes the corneal elasticity and by controlling the distribution of the elasticity, we are able to change the refractive power of the cornea.

State Of Development

  • Apparatus has been used in in vitro studies in collagen hydrogels
  • Method has been tested in vivo using cadaver rabbit eyes and shown to be comparable to the use of UV A for crosslinking of collagen

Suggested uses

  • Treatment of corneal ectasia, refractive errors, and astigmatism
  • Treatment of corneal infections and tumors
  • Advantages

    • Precise control of radiation delivery minimizes damage to the eye during cornea treatment
    • Increases safety for patients undergoing cornea treatment for ectasia and similar conditions


      Chai D, Juhasz T, Brown DJ, Jester JV. Nonlinear optical collagen cross-linking and mechanical stiffening: a possible photodynamic therapeutic approach to treating corneal ectasia. Journal of Biomedical Optics. 2013;18(3):038003. Link.


      Bradford SM, Brown DJ, Juhasz T, Mikula E, Jester JV: Nonlinear optical corneal collagen crosslinking (NLO CXL) of ex vivo rabbit eyes. J Cat Ref Surg 42:1660-1665, 2016. Link




      Patent Status

      Country Type Number Dated Case
      United States Of America Issued Patent 9,095,414 08/04/2015 2011-816
      United States Of America Published Application 2020/003823 02/06/2020 2017-573
      United States Of America Published Application 20150320599 11/12/2015 2011-816

      Additional Patent Pending


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  • Jester, James V.

Other Information



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