Skip to main content
  • 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: Shahzad I. Mian, MD,1 Elizabeth T. Viriya, MD,2 Sumayya Ahmad, MD, Methodologist,3 Guillermo Amescua, MD,4 Albert Y. Cheung, MD,5 Daniel S. Choi, MD,6 Vishal Jhanji, MD, FRCS, FRCOphth,7 Amy Lin, MD,8 Michelle K. Rhee, MD,9 Francis S. Mah, MD, Co-Chair,10 Divya M. Varu, MD, Co-Chair,11

    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 and Visual Sciences, University of Michigan, Ann Arbor, Michigan
    2Department of Ophthalmology, Lincoln Hospital/NYC Health+ Hospitals, Bronx, New York
    3Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, New York
    4Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
    5Virginia Eye Consultants, Norfolk, Virginia, Assistant Professor, Department of Ophthalmology, Eastern Virginia Medical School
    6Cataract and Vision Center of Hawaii, Honolulu, Hawaii
    7Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
    8John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
    9Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, Elmhurst Hospital, Mount Sinai Services, Elmhurst, 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

    The impact of corneal edema on activities of daily living―particularly those influenced by ambient light conditions at home, work, and during leisure activities―is often under appreciated. Standard measurement of visual acuity does not give a true representation of the patient's functional vision.

    A refraction over a rigid gas-permeable (RGP) or scleral contact lens can be very helpful in determining visual loss is due to a corneal surface irregularity.

    Endothelial function is best evaluated by casual history and examination with slit-lamp biomicroscopy. When diffuse endothelial guttae are present on slit-lamp biomicroscopy examination, serial pachymetric measurements and tomographic evaluation may help monitor endothelial function. Specular microscopy is not a direct measure of endothelial function or functional reserve. Corneal topography revealing irregular isopachs, nasal displacement of the thinnest cornea, and posterior depression may help predict Fuchs dystrophy patients at greater risk of endothelial decompensation.

    If corneal decompensation is likely to occur in the near future, the surgeon should consider modifying the intraocular lens (IOL) power calculation to adjust for changes likely to be induced by future endothelial keratoplasty. This often involves a hyperopic shift after Descemet's stripping automated endothelial keratoplasty (DSAEK) and less of a hyperopic shift with Descemet's membrane endothelial keratoplasty (DMEK). A full discussion with the cataract and Fuchs dystrophy patient about IOL-power selection and the added risks of subsequent corneal decompensation is very important and helps to shape the patient's expectations with respect to their condition and the surgery.

    Endothelial keratoplasty (EK) has supplanted penetrating keratoplasty (PK) as the procedure of choice in cases of endothelial failure in the absence of corneal scarring because patients achieve more rapid visual rehabilitation and reduced risk of immune-mediated rejection of the transplanted tissue and less induced astigmatism.

    Many corneal opacities start as persistent, nonhealing epithelial defects that opacify as a result of infection, inflammation, tissue breakdown, and/or scarring. Nerve growth factor has been shown to be effective in treating nonhealing epithelial defects in the setting of neurotrophic keratopathy.

    Literature Search

    Corneal Edema and Opacification PPP - 2023 - Literature Search