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  • AAO PPP Cornea/External Disease Committee, Hoskins Center for Quality Eye Care
    Cornea/External Disease
    By the American Academy of Ophthalmology Preferred Practice Pattern Cornea/External Disease Committee: Vishal Jhanji, MD, FRCS, FRCOphth,1 Sumayya Ahmad, MD, Methodologist,2 Guillermo Amescua, MD,3 Albert Y. Cheung, MD,4 Daniel S. Choi, MD,5 Amy Lin, MD,6 Shahzad I. Mian, MD,7 Michelle K. Rhee, MD,8 Elizabeth T. Viriya, MD,9 Francis S. Mah, MD, Co-Chair,10 Divya M. Varu, MD, Co-Chair11

    As of November 2015, the PPPs are initially published online only in the Ophthalmology journal and may be freely downloaded in their entirety by all visitors. Open the PDF for this entire PPP or click here to access the PPP on the journal's site. Click here to access the journal's PPP collection page.

    1Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
    2Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, New York
    3Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
    4Virginia Eye Consultants, Norfolk, Virginia, Assistant Professor, Department of Ophthalmology, Eastern Virginia Medical School
    5Cataract and Vision Center of Hawaii, Honolulu, Hawaii
    6John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
    7Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
    8Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, Elmhurst Hospital, Mount Sinai Services, Elmhurst, New York
    9Department of Ophthalmology, Lincoln Hospital/NYC Health+ Hospitals, Bronx, New York
    10Departments of Cornea and External Diseases, Scripps Clinic Torrey Pines, La Jolla, California
    11Dell Laser Consultants, Austin, Texas

    Highlighted Findings and Recommendations for Care

    Patients with unstable refractions should be evaluated for evidence of corneal ectasia.

    Since corrected distance visual acuity (CDVA) may not completely characterize visual function in patients with corneal ectasia, the ophthalmologist needs to include other measures such as corneal topography and tomography.

    Signs of corneal ectasia can include, but are not limited to, inferior steepening, superior flattening, skewing of radial axes on power topographic maps, abnormal islands of elevation anteriorly and/or posteriorly on tomography, and decentered or abnormal corneal thinning and/or abnormal rate of change of corneal thickening from the center to the periphery.

    Patients being evaluated for keratorefractive surgery should be evaluated for corneal ectasia following a period of contact lens abstinence. Corneal topography and tomography should be reviewed for evidence of irregular astigmatism or abnormalities suggestive of keratoconus or other forms of corneal ectasia. Overall, the risk of corneal ectasia is lower after photorefractive keratectomy (PRK) and small-incision lenticule extraction (SMILE) compared with laser in-situ keratomileusis (LASIK). This has been attributed to higher residual stromal bed thickness and absence of the corneal flap in PRK.

    Corneal cross-linking (CXL) reduces the risk of progressive ectasia in patients with keratoconus. It also stabilizes corneal ectasia occurring after keratorefractive surgery but is generally not as effective in this latter setting. Corneal cross-linking is the recommended treatment for progressive keratoconus because it stabilizes the cornea and reduces the risk of progressive ectasia. It also stabilizes corneal ectasia occurring after keratorefractive surgery but is generally less effective in this later setting.

    The long-term stabilizing effect of CXL may be more cost effective than corneal transplantation.

    Specialty contact lenses, including hybrid and scleral lenses, should be trialed for visual rehabilitation prior to keratoplasty and may delay and even eliminate the need for corneal transplantation.

    Penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK) may be used to treat corneal ectasia. The advantages of DALK include no risk for endothelial rejection and lower risk of globe rupture than with PK. The progressive endothelial cell loss following DALK may also be less than the loss following PK.

    Literature Search

    Corneal Ectasia PPP - 2023 - Literature Search