Corneal Dystrophies

Corneal Dystrophies



Epithelial basement membrane (EBM) dystrophy is a common epithelial dystrophy that can cause painful recurrent corneal erosions and/or decreased vision.

Etiology and Pathology

• EBM dystrophy is caused by an abnormality of production of EBM that extends into the epithelium, leading to multiple basement membrane layers in the corneal epithelium. Trapped epithelial cells can form “Cogan microcysts.”

• Typically degenerative, occasionally autosomal dominant (transforming growth factor beta-induced [TGFBI] gene of chromosome 5q31)


• Slit-lamp examination shows map-like lines, dots (microcysts), and/or fingerprint-like epithelial lesions, which may occur singly or in various combinations (Fig. 5-1, eFig. 5-1A-J). These findings are best seen with retroillumination and with a broad slit beam from the side. “Negative staining” from slightly elevated areas of epithelium may be seen with fluorescein dye.

• Eyes with recurrent erosions may have minimal clinical findings, localized areas of loose epithelium, or a frank epithelial defect.

Differential Diagnosis

• Other anterior corneal dystrophies, such as Meesmann dystrophy and Reis-Bücklers and Thiel-Behnke dystrophies


• Very good with appropriate treatment, although some patients have recalcitrant recurrent erosions.

FIGURE 5-1. Epithelial basement membrane (EBM) dystrophy. A. Reduplicated EBM causing map-like changes is readily visible centrally. B. Large map-like opacities are present throughout the central cornea, causing complaints of monocular “diplopia,” better described as “shadow vision.”

FIGURE 5-1. (continued) C. Map-like changes in this eye are almost confluent centrally, resulting in significant visual distortion. D. The map-like changes here are often referred to as a “mare’s tail” pattern.

FIGURE 5-1. (continued) E. Fluorescein stain and the cobalt blue light view of the cornea shown in D. Significant “negative staining” is evident because of areas of elevated epithelium. These elevated areas can cause foreign-body sensation and/or decreased vision. F. Dot changes of EBM dystrophy. These creamy white Cogan microcysts are tiny pockets of surface epithelial cells trapped beneath an abnormal EBM.

FIGURE 5-1. (continued) G. A large area of epithelial microcysts is seen superiorly. H. Retroillumination view of the same eye seen in G highlights the epithelial microcysts.

FIGURE 5-1. (continued) I. Fingerprint-like changes of EBM dystrophy in retroillumination. These parallel lines and bleblike changes are a result of irregularities in the EBM. They are causing irregular astigmatism and decreased vision. J. Fingerprint lines in a “mare’s tail” pattern are seen centrally in this eye with EBM dystrophy.

FIGURE 5-1. (continued) K. Chronic severe map-like changes have caused underlying anterior stromal scarring in this eye with EBM dystrophy, resulting in poor vision. Owing to the presence of anterior stromal scarring, this eye was treated with excimer laser PTK and not a diamond burr polishing procedure. L. Seven weeks after excimer laser PTK of the eye seen in K, the map-like changes and most of the anterior stromal scarring are gone, with significant improvement in the patient’s vision. PTK: phototherapeutic keratectomy.


Meesmann dystrophy is a rare bilateral epithelial disorder that can cause ocular irritation and photophobia.

Etiology and Pathology

• Meesmann dystrophy is an autosomal dominant (keratin K3 and keratin K12 genes of chromosomes 12q13 and 17q12, respectively) condition in which hundreds of tiny vesicles containing periodic acid-Schiff (PAS)-positive “peculiar substance” are found in the epithelium.


• Retroillumination demonstrates myriad tiny, translucent, epithelial cysts that extend to the limbus and are most numerous in the interpalpebral region, but can be sectorial. The lesions appear gray or clear under direct illumination (Fig. 5-2, eFig. 5-2A-C).


• Good, although some patients will have chronic symptoms.

FIGURE 5-2. Meesmann dystrophy. A. Multiple tiny, translucent, epithelial cysts are apparent in retroillumination. They tend to be more prominent in the interpalpebral zone. B. On direct illumination, the microcysts are gray in color but are difficult to see. On illumination of the iris, at the 3 o’clock edge of the pupil, myriad microcysts are visible.


Lisch corneal dystrophy is a rare, typically bilateral, epithelial disorder that can cause decreased vision if the visual axis is involved.

Etiology and Pathology

• Lisch corneal dystrophy is an X-linked dominant condition (chromosome Xp22.3) in which PAS-positive vacuolated cells are found in the epithelium.


• Gray-white epithelial opacities in whorled, flame, or feather-shaped pattern. The opacities can progress and change shape over time (Fig. 5-3A and B, eFig. 5-3A-E).


• Good, although rare patients will have chronic symptoms.

FIGURE 5-3. Lisch corneal dystrophy. A. A large paracentral area of gray-white epithelial opacity with flameshaped edges is seen in this left eye of a 60-year-old patient with Lisch corneal dystrophy. B. The areas of abnormal epithelium of the left eye of the patient with Lisch corneal dystrophy seen in A are highlighted using retroillumination off the retina.


Reis-Bücklers (corneal dystrophy of Bowman layer, type I-CDB 1) and Thiel-Behnke (corneal dystrophy of Bowman layer, type II-CDB 2) dystrophies are uncommon, bilateral, symmetric, very similar dystrophies of Bowman membrane that cause pain and decreased vision early in life.


Reis-Bücklers and Thiel-Behnke dystrophies are autosomal dominant (TGFBI gene of chromosome 5q31) disorders that cause damage and scarring to Bowman membrane and the anterior stroma.


• Honeycomb appearance because of reticular, ring-shaped, subepithelial opacities that are most dense centrally but may involve the entire cornea. With time, they can progress deeper into the stroma (Fig. 5-4A-G, eFig. 5-4A and B).

• Although difficult to distinguish clinically, Reis-Bücklers displays more irregular diffuse opacities with clear interruptions, whereas Thiel-Behnke exhibits multiple flecks with reticular formation.

• On electron microscopy, Reis-Bücklers demonstrates subepithelial electron-dense, rod- or trapezoidal-shaped bodies, as opposed to Thiel-Behnke, which demonstrates curly fibers.

Differential Diagnosis

• Other anterior or stromal dystrophies (e.g., EBM dystrophy, granular dystrophy, macular dystrophy)


• Excimer laser PTK can be quite successful in improving vision and decreasing painful episodes in many cases. Keratoplasty may be required in advanced cases. Recurrence in the donor graft is common after corneal transplantation and also after PTK (Fig. 5-4H and I, eFig. 5-4H and I). Excimer laser PTK can often be repeated or performed for recurrence after keratoplasty.

FIGURE 5-4. Reis-Bücklers dystrophy. A. A slight reticular pattern can be seen mainly in the central cornea in this eye with relatively mild Reis-Bücklers dystrophy. B. This eye has moderate changes of Reis-Bücklers dystrophy. It primarily involves the central cornea, but the opacity approaches the limbus inferiorly.

FIGURE 5-4. (continued) C. This eye with advanced Reis-Bücklers dystrophy has diffuse, reticular, limbus-to-limbus subepithelial, and anterior stromal opacity. There are few if any clear spaces. D. This eye also has advanced Reis-Bücklers dystrophy. Fortunately, the vision improved significantly after excimer laser PTK.

FIGURE 5-4. (continued) E. Central reticular, honeycomb-shaped opacity is present in the left eye of this 22-yearold patient with Reis-Bücklers corneal dystrophy. F. An anterior segment OCT of the eye seen in E demonstrating significant opacity of Reis-Bücklers corneal dystrophy at the level of Bowman layer. G. A high-resolution anterior segment OCT of the cornea seen in E and F highlights the opacity of Reis-Bücklers at the level of Bowman layer.

FIGURE 5-4. (continued) H. Recurrent Reis-Bücklers a few years after a penetrating keratoplasty. Unfortunately, Reis-Bücklers recurs relatively rapidly after corneal transplantation. I. This eye also has recurrent Reis-Bücklers dystrophy several years after penetrating keratoplasty. Note the honeycomb opacity centrally and involvement of the entire corneal periphery.

FIGURE 5-4. (continued) J. Significant recurrence of the dystrophy can be seen many years after a corneal transplant for Reis-Bücklers corneal dystrophy in this 44-year-old patient. The patient underwent subsequent excimer laser PTK. K. One month after excimer laser PTK of the eye with recurrent Reis-Bücklers corneal dystrophy seen in J, the central cornea is essentially clear, with tremendous improvement in the patient’s vision. OCT: optical coherence tomography; PTK: phototherapeutic keratectomy.


Gelatinous drop-like corneal dystrophy is a rare condition that causes significant symptoms early in life.

Etiology and Pathology

• Gelatinous drop-like corneal dystrophy is an autosomal recessive condition (tumor-associated calcium signal transducer 2 gene of chromosome 1p32).

• Histopathology: subepithelial and stromal amyloid deposits


• There are a variety of presentations, including relatively flat subepithelial opacities similar to band keratopathy, small or large groups of elevated nodules (“mulberry” pattern) (Fig. 5-5A), and larger nodular lesions (“kumquat” pattern).

• Superficial and deep neovascularization may develop.

• Superficial and deep stromal opacification may also develop.

Differential Diagnosis

• Other anterior or stromal dystrophies (e.g., macular dystrophy, Reis-Bücklers dystrophy, granular dystrophy)

Oct 13, 2019 | Posted by in OPHTHALMOLOGY | Comments Off on Corneal Dystrophies

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