| Salzmann’s Nodular Degeneration  Signs and Symptoms
Most cases of Salzmann’s nodular degeneration present
asymptomatically. Discomfort does not usually occur until later stages, at which time
recurrent corneal erosion (RCE) may ensue. Patients manifesting RCE typically report
photophobia, blepharospasm, tearing, and decreased acuity. In between bouts of RCE,
non-specific "dry eye" complaints such as burning or grittiness are typical.
Clinically, Salzmann’s degeneration appears as an accumulation of
bluish-white superficial nodules in the mid-peripheral cornea. Generally, the eye is not
inflamed unless there is associated corneal erosion. In that event, there will be limbal
injection, corneal edema, and an anterior chamber reaction.
There are conflicting reports regarding the laterality of
Salzmann’s degeneration; an older study reports a unilateral presentation in 80
percent of cases, while a more recent study suggests a bilateral predilection in 80
percent. The condition is seen more frequently in women than in men.
Patients with Salzmann’s degeneration usually describe a previous
episode of ocular inflammation, often in childhood. Associated disorders may include
phlyctenular disease, vernal keratoconjunctivitis, trachoma, or interstitial keratitis.
Patients with a history of epithelial basement membrane dystrophy or corneal surgery may
also be at increased risk.
Pathophysiology
At the cellular level, the nodules seen in Salzmann’s degeneration
represent clumped masses of collagen fibrils anterior to Bowman’s membrane. Experts
speculate that these peripheral accumulations of collagen are produced by fibroblasts
within the conjunctiva or limbal vessels. In some cases, transmission electron microscopy
has demonstrated reduplication of the epithelial basement membrane. Descemet’s
membrane and the corneal endothelium are characteristically unaltered, however.
One theory behind the development of Salzmann’s degeneration
suggests that the inciting corneal inflammation creates an irregular surface, allowing for
uneven tear film distribution and exposure. A process known as hyalization ensues, which
is the same process responsible for the development of conjunctival pinguecula. As the
nodules grow in size, there is progressive damage and scarring at the level of
Bowman’s membrane. This ultimately results in epithelial erosion and potential
impairment of acuity.
Management
Mildly asymptomatic cases of Salzmann’s degeneration may be managed
with topical lubricants and/or a bandage contact lens. Prophylactic antibiosis is
advisable if epithelial defects are significant. In more severe cases, superficial
keratectomy may be utilized to remove the nodules from the anterior cornea.
Phototherapeutic keratectomy (PTK) is also an option. If significant scarring is present,
or if chronic epithelial breakdown makes the condition unmanageable, lamellar or
penetrating keratoplasty may be the only recourse.
Clinical Pearls
The critical issue in managing Salzmann’s
degeneration is proper diagnosis. Conditions such as band keratopathy, spheroid
degeneration (climatic droplet keratopathy), and corneal keloids may all present with a
similar clinical appearance. Consult a corneal specialist in those cases where diagnosis
is elusive.
It may be tempting to use topical corticosteroids in
Salzmann’s degeneration, particularly if the patient is symptomatic. However, since
this condition is non-inflammatory in nature, steroids will have little effect.
Additionally, the use of steroids introduces an unnecessary risk in patients with a
compromised epithelium.
Other reports in this section
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