Consultant's Corner
Defining Corneal Exhaustion Syndrome (CES)
by Janet Gilman, COT, FCLSA
Consultation Manager
CES (corneal exhaustion syndrome) is caused by longtime chronic depletion of oxygen to the cornea. CES can occur from the long term wear of non-oxygen permeable PMMA lenses as well as over wear of low Dk GP and soft contact lenses with a poor fit or tear exchange. Unfortunately, corneal exhaustion syndrome can lead to previously successful long-term wearers suddenly becoming intolerant contact lenses.
Some of the signs related to CES and its associated hypoxia include epithelial or stromal edema, 2mm or more of corneal pannus unrelated to 3 and 9 o’clock staining, and conjunctival changes. Consequences to long term hypoxia may include microcysts, limbal hyperemia, neovascularization, and small increases in myopia. Contact lens wear associated with CES can also lead to corneal warpage and distortion and may result in spectacle blur which is a reversible loss of acceptable spectacle visual acuity immediately following contact lens wear. This corneal distortion may be a result of hypoxia or mechanical change such as lens binding and poorly centered gas permeable lenses.
Ideally, the best way to resolve corneal exhaustion would be to discontinue lens wear and wait until the corneal topography stabilizes. Once the cornea is stable, refit the patient with a GP lens with a high Dk. Typically, when a higher oxygen permeable material is used, it may result in decreased wettability and increased deposition. This can now be rectified by choosing to use plasma treatment to enhance the wettability for the patient as well as improving their corneal health.
It may take a “salesman approach” to explain to the patient why you will need to have them discontinue lens wear for a short period of time, but the end result will improve their corneal health and hopefully, extend their years of successful contact lens wear.
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