CHAptER 7: Corneal Dystrophies and Ectasias ● 141

Category 1

pathology Light microscopy shows subepithelial and stromal amyloid deposits. Disrup-tion of epithelial tight junctions leads to abnormally high epithelial permeability. Con-focal microscopy shows irregular, elongated epithelial cells with large accumulations of brightly reflective material noted within or beneath the epithelium and within the anterior stroma. Amyloid deposition is noted in the basal epithelial layer on transmission electron microscopy. See also Chapter 8 for a more complete discussion of amyloidosis.

clinical presentation Onset occurs in the first to second decade of life with groups of multiple small nodules (mulberry configuration) or with subepithelial lesions that may appear similar to those of band keratopathy (Fig 7-5A, B). The lesions are visible on fluo-rescein staining. There is a significant decrease in vision, with photophobia, irritation, and tearing, as well as progression of protruding subepithelial lesions. Superficial vasculariza-tion is often seen. Stromal opacification or larger nodular lesions (kumquat- like lesions) may develop (Fig 7-5C).

management The lesions recur within a few years following superficial keratectomy, la-mellar keratoplasty (LK), or penetrating keratoplasty (PK). Soft contact lenses are effec-tive in reducing the abnormal epithelial permeability in an effort to decrease recurrence.

Ide T, Nishida K, Maeda N, et al. A spectrum of clinical manifestations of gelatinous drop-like corneal dystrophy in Japan. Am J Ophthalmol. 2004;137(6):1081–1084.

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Figure 7-5 Gelatinous droplike corneal dystrophy. A, Mulberry type. B, Band keratopathy type. C, Kumquat- like type. (Reproduced with permission from Weiss JS, Møller HU, Aldave AJ, et al. IC3D classification of corneal dystrophies—edition 2. Cornea. 2015;34(2):130).

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142 ● External Disease and Cornea

Epithelial–Stromal TGFBI Dystrophies

Reis-Bücklers corneal dystrophy (RBCD)

Alternative names Corneal dystrophy of Bowman layer type 1 (CDB1), atypical granular corneal dystrophy

Inheritance AD

Category 1

pathology On light microscopy, the Bowman layer is disrupted or absent and replaced by a sheetlike connective tissue layer with granular deposits that stain red with Masson trichrome stain. Transmission electron microscopy shows subepithelial electron- dense, rod-shaped bodies, which are immunopositive for the TGFBI protein, keratoepithelin. Electron micros-copy is needed to histologically distinguish RBCD from Thiel- Behnke corneal dystrophy (TBCD), which has curly fibers (see the next section). On confocal microscopy, distinct de-posits are found in the epithelium and Bowman layer. The basal epithelial cell layer shows high reflectivity associated with small granular deposits without any shadows (Fig 7-6A), which would be typical of TBCD. The Bowman layer is replaced with highly reflective irreg-ular material. Greater hyperreflectivity is seen at the Bowman layer in RBCD than in TBCD.

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Figure 7-6 Reis-Bücklers corneal dystrophy. A, Confocal microscopy reveals highly reflective material without shadows in the basal epithelium. B, Coarse geographic opacity of the su-perficial cornea. C, Broad, oblique illumination shows a dense, reticular, superficial opacity. D, Slit-lamp photograph showing irregularities at the level of the Bowman layer. (Part A reproduced with permission from Weiss JS, Møller HU, Aldave AJ, et al. IC3D classification of corneal dystrophies—edition 2. Cornea. 2015;34(2):132. Parts B–D reproduced with permission from Weiss JS, Møller HU, Lisch W, et al. The IC3D classification of the corneal dystrophies. Cornea. 2008;27(suppl 2):S1–S42.)

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