2020–2021 BCSC Basic and Clinical Science Course™
4 Ophthalmic Pathology and Intraocular Tumors
Part I: Ophthalmic Pathology
Chapter 6: Cornea
Degenerations, Depositions, and Ectasias
Corneal degenerations are secondary changes that occur in previously normal tissue. They are often associated with aging, are not inherited, and are not necessarily bilateral. See BCSC Section 8, External Disease and Cornea, for additional discussion.
Salzmann Nodular Degeneration
Salzmann nodular degeneration is a slowly progressive degenerative condition of the cornea. Often asymptomatic, it is characterized by the appearance of nodular gray-white to bluish, flat or raised opacities that vary in number and size and are located in the central or paracentral cornea (Fig 6-9A). Usually, the condition is bilateral and occurs in middle-aged and older individuals, with a female preponderance. It is typically associated with chronic ocular surface inflammation. Although the condition is often idiopathic, underlying causes include (from most to least common)
meibomian gland dysfunction (MGD)
conditions that lead to recurrent erosions
dry eye/keratoconjunctivitis sicca
contact lens wear (especially hard contact lenses)
peripheral corneal vascularization
phlyctenular keratitis, vernal keratoconjunctivitis
Figure 6-9 Salzmann nodular degeneration. A, Clinical photograph. Note the gray-white to bluish elevated superficial opacities. B, Histologic examination of a superficial keratectomy specimen (PAS stain) shows irregular epithelial thickness and loss of Bowman layer, as well as replacement of the latter with disorganized collagenous tissue (asterisk).
(Courtesy of George J. Harocopos, MD.)
Histologic examination reveals focal absence of Bowman layer with nodular, sclerotic subepithelial collagenous and/or fibrotic material (pannus). Sometimes there is focal thickening of the epithelial basement membrane (Fig 6-9B). The Bowman layer may be fragmented or absent.
Paranjpe V, Galor A, Monsalve P, Dubovy SR, Karp CL. Salzmann nodular degeneration: prevalence, impact, and management strategies. Clin Ophthalmol. 2019;13:1305–1314.
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.