Get to Know Your Dystrophies
Differentiating the various etiologies can be difficult, but with the right training and diagnostic tools, you can find the right diagnosis and manage the patient accordingly.
By Irene Frantzis, OD, and Eva Duchnowski, OD
March 1, 2020
Corneal dystrophies can profoundly impact our patients’ lives, and prompt diagnosis of the right dystrophy is imperative to minimize that impact. This lesson reviews signs and symptoms associated with various corneal dystrophies and then explores options for managing patient symptomology.
Irene Frantzis, OD, and Eva Duchnowski, OD.
This course is COPE approved for 1 hour of CE credit. Course ID is 52584-AS. Check with your state licensing board to see if this counts toward your CE requirements for relicensure.
This continuing education course is joint-sponsored by the Pennsylvania College of Optometry.
The authors, reviewers and editorial staff have no relationships to disclose.
Corneal dystrophies are typically defined as hereditary, bilateral, progressive alterations to the cornea not associated with systemic disease or prior inflammation. IC3D classification of corneal dystrophies is anatomically based and divided into four categories: epithelial and subepithelial dystrophies, epithelial-stromal transforming growth factor beta-induced (TGFBI) dystrophies, stromal dystrophies, and endothelial dystrophies.1 This article provides an overview of signs and symptoms associated with various corneal dystrophies and explores options to manage patient symptomology.
Epithelial and Subepithelial Dystrophies
Epithelial basement membrane dystrophy (EBMD), also known as map-dot-fingerprint or Cogan’s microcystic dystrophy, is common and is caused by abnormal epithelial basement membrane adhesions usually occurring as a consequence of degenerative changes or trauma. Rarely, it may be due to an inherited mutation.1 Clinical signs include irregular, hazy areas of epithelium in map, dot or linear patterns that negatively stain with fluorescein. Patients may be asymptomatic or complain of photophobia, pain secondary to erosions or decreased visual acuity (VA) due to irregular astigmatism or corneal opacity.
Meesmann corneal dystrophy (MECD) is a less common epithelial layer dystrophy inherited autosomal dominantly that presents clinically as hazy epithelium with microcysts.1 Of those affected, 85% will show microcysts covering the entire cornea.1 Although MECD patients may be asymptomatic, some may complain of symptoms similar to those found in EBMD such as decreased VA, light sensitivity or pain.
|Fig. 1. Above, a 40-year-old male patient with granular
corneal dystrophy. His BCVA in his right eye was 20/30-2.
Below, his nine-year-old son presented with less dense
stromal deposits, and his BCVA was 20/25 in his right eye.
Reis-Bucklers dystrophy is inherited in an autosomal dominant manner and leads to damage and focal opacities in Bowman’s membrane and the anterior stroma.1 Clinically, these opacities will be ring-shaped and most dense centrally, although they can involve the entire cornea. VA is usually reduced from a young age and will slowly deteriorate over time. Patients may also complain of pain secondary to corneal erosions.
Lattice dystrophy is also an autosomal dominant inherited dystrophy. This gene mutation leads to amyloid protein deposits in the anterior stroma that present clinically as linear opacities.1 Patients may complain of pain secondary to erosions or decreased VA.
Granular dystrophy is caused by an autosomal dominant gene mutation that leads to hyaline protein deposits in the anterior stroma.1 These deposits are bread crumb-like and increase in size and number with age (Figure 1). Patients may complain of glare, photophobia, painful erosions or decreased VA.
Avellino dystrophy, also known as granular type 2 or combined granular-lattice dystrophy, is inherited in an autosomal dominant fashion and leads to both hyaline and amyloid deposits in the stroma.1 Bread crumb-like opacities are seen similar to those in granular dystrophy, but in combination with deeper stromal refractile lines such as those found in lattice dystrophy (Figure 2). Patients may complain of glare, photophobia, painful erosions or severely decreased VA.
Macular dystrophy is inherited in an autosomal recessive manner.1 This gene mutation leads to a defect in corneal glycosaminoglycans, which presents clinically as anterior stromal opacities similar in shape to those found in granular dystrophy, but with greater severity.1 Patients may complain of glare, photophobia, painful erosions or severely decreased VA.
Schnyder crystalline corneal dystrophy, autosomal dominantly inherited, presents before the third decade of life.1 Corneal findings vary with age: patients 23 and younger present with a circular central stromal haze, those between 23 and 38 present with arc-shaped bands of haze in the midperipheral cornea and patients older than 38 often have dense stromal haze in the limbal region.1 VA decreases over time and glare symptoms increase.
|Fig. 2. This 38-year-old female with Avellino corneal
dystrophy was symptomatic for decreased vision, with
BCVA of 20/30.
Fuchs’ endothelial dystrophy may be inherited or sporadic.1 Endothelial cells slowly die, disrupting normal fluid gradients in the cornea. Clinical signs include endothelial guttata, stromal or epithelial edema, bullae, low endothelial cell counts or even corneal scarring with chronicity (Figure 3). Patients may complain of painful erosions or decreased VA worse in the mornings.
Posterior polymorphous dystrophy is caused by a gene mutation that affects Descemet’s membrane and the endothelium.1 Clinical findings may be asymmetric and manifest as linear or vesicular changes with irregular, scalloped edges at the level of Descemet’s membrane. Of these patients, 25% will also have iridocorneal adhesions, while 15% will have elevated intraocular pressure (IOP).1 Patients may be asymptomatic or present with decreased VA due to corneal edema and pain if corneal bullae develop.
Congenital hereditary endothelial dystrophy, inherited in an autosomal recessive manner in the majority of cases, presents at birth with bilateral cloudy corneas.1 Additional findings include thicker than average corneas, highly reduced endothelial cell counts and nystagmus. Less frequently, patients present with band keratopathy and elevated IOP.1
As there is no cure for these dystrophies, treatment should focus on managing patient symptoms.
|Fig. 3. At left, corneal guttata of a 43-year-old female as
seen on slit lamp. At right, corneal guttata as seen with a
Autologous or umbilical cord serum are pharmacologic options for patients who exhibit minimal RCE improvement with topical treatments. Umbilical cord serum has a high concentration of growth factors, and research shows it decreases the frequency of erosions compared with lubricants alone.3
Contact lens options are also available for patients who fail with other topical treatments. Bandage lenses can help protect the epithelium from mechanical forces with efficacy similar to topical lubricants, and patients may experience earlier pain relief.4 Scleral lenses can potentially resolve epithelial defects by providing mechanical protection and continuous hydration to the epithelium (Figure 4).5 Research also suggests amniotic membranes can promote ocular surface healing with minimal adverse effects.6 For recalcitrant cases, surgical options include micropuncture, diamond burr debridement, phototherapeutic keratectomy and alcohol delamination.
When patients present with decreased VA, clinicians should take corneal topographies to evaluate for the presence of irregular astigmatism. In these cases, gas permeable, scleral and hybrid lenses are viable options for visual improvement.
|Fig. 4. At left, a 50-year-old female with EBMD. Her BCVA
was 20/60. At right, this patient was successfully fit in
scleral lenses and achieved 20/20. The optic section of the
fit shows, from left to right, the front surface of the lens
(white hyper-reflective beam), contact lens thickness (black
band) and corneal vault (green band)—the space between
the contact lens back surface and the cornea.
Many of the corneal dystrophies are capable of resulting in corneal edema. Traditional treatment of corneal edema includes the use of topical lubricants and hyperosmotic drops or ointments. The surgical options available for these patients aim to replace the dysfunctional endothelium. Descemet’s stripping automated endothelial keratoplasty or Descemet’s membrane endothelial keratoplasty is preferred over traditional PK for patients with only endothelial dysfunction because of decreased likelihood of serious adverse effects such as graft rejection.9
Rho-associated kinase (ROCK) inhibitors may play a role in the future management of corneal edema, as these drugs have been shows to promote endothelial cell proliferation.10 Case reports found ROCK inhibitors to be successful in improving corneal clarity and vision, while also significantly decreasing corneal edema.10
Corneal collagen crosslinking has been proposed as yet another way of managing corneal edema. Crosslinking is currently used for preventing the progression of corneal ectasia, but also has the ability to reduce stromal swelling.11 Case studies show a modified corneal crosslinking procedure was successful in decreasing corneal thickness and improving visual fluctuation in association with corneal edema.11
Corneal dystrophies can be challenging to diagnose and manage. It’s imperative we handle these cases in a timely fashion, as they can profoundly impact our patients’ lives. Fortunately, our knowledge and treatment options continue to expand, and we look forward to further developments to better our patients’ quality of life.
Dr. Frantzis is a Cornea and Contact Lens resident at SUNY College of Optometry. She specializes in complicated contact lens fittings and diagnosing and managing patients with corneal anomalies.
Dr. Duchnowski is the section chief of Contact Lens Service at the University Eye Care Center and the director of Cornea and Contact Lens externship at SUNY College of Optometry.
1. Weiss JS, Møller HU, Aldave, AJ, et al. IC3D classification of corneal dystrophies. 2nd ed. Cornea. 2015;34:117–59.
2. Wang L, Tsang H, Coroneo M. Treatment of recurrent corneal erosion syndrome using the combination of oral doxycycline and topical corticosteroid. Clin Exp Ophthalmol. 2008;36:8-12.
3. Yoon K, Choi W, You I, Choi J. Application of umbilical cord serum eye drops for recurrent corneal erosions. Cornea. 2011;30:744-8.
4. Ahad MA, Anandan M, Tah V, et al. Randomized controlled study of ocular lubrication versus bandage contact lens in the primary treatment of recurrent corneal erosion syndrome. Cornea. 2013;32:1311-4.
5. Rosenthal P, Cotter JM, Baum J. Treatment of persistent corneal epithelial defect with extended wear of a fluid-ventilated gas-permeable scleral contact lens. Am J Ophthalmol. 2000;130:33-41.
6. Pachigolla G, Prasher P, Di Pascuale MA, et al. Evalution of the role of ProKera in the management of ocular surface and orbital disorders. Eye Contact Lens. 2009;35(4):172-5.
7. Stewart OG, Pararajasegaram P, Cazabon J, Morrell AJ. Visual and symptomatic outcome of excimer phototherapeutic keratectomy (PTK) for corneal dystrophies. Eye. 2002;16:126-31.
8. Kawashima M, Kawakita T, Den S, et al. Comparison of deep lamellar keratoplasty and penetrating keratoplasty for lattice and macular corneal dystrophies. Am J Ophthalmol. 2006;142:304-9.
9. Hjortdal J, Ehlers N. Descemet’s stripping automated endothelial keratoplasty and penetrating keratoplasty for Fuchs’ endothelial dystrophy. Acta Ophthalmol. May 2009;87:310-4.
10. Koizumi N, Okumura N, Ueno M, et al. Rho-associated kinase inhibitor eye drop treatment as a possible medical treatment for Fuchs corneal dystrophy. Cornea. 2013;32:1167-70.
11. Hafezi F, Dejica P, Majo F. Modified corneal collagen crosslinking reduces corneal oedema and diurnal visual fluctuations in Fuchs dystrophy. Br J Ophthalmol. 2010;94:660-1.