A 69-year-old white female was referred to my care, by the cornea surgeon in our group, to discuss contact lens options for irregular astigmatism in her right eye. The reason: The patient’s irregular astigmatism caused monocular diplopia with spectacle correction and her BCVA is 20/50 in the right eye. Medical history revealed Salzmann’s nodular degeneration (SND) for which she underwent three superficial keratectomies (SK) that resulted in the resolution of her SND-caused diplopia, blur and foreign body sensation. Unfortunately, her symptoms returned a few months to a year after each procedure.
Here, I provide an overview of SND, how to treat it, how I managed our patient and how she is doing today.
|Nodular Corneal Degeneration||H18.45|
SND is named for Austrian ophthalmologist Maximilian Salzmann who identified nodular keratopathy in several patients in 1925. This non-inflammatory and slowly progressive condition is more common in women in their 50s.
The condition has no clearly defined etiology, although prior infectious keratitis has been considered a possible inciting event. Also, meibomian gland dysfunction is the most common ocular comorbidity. In addition, some authors suggest a correlation with contact lens use, dry eye disease, peripheral vascularization, comorbid systemic autoimmune disease or a genetic predisposition. Of note: A radiological study of SND patients in 2007 showed that all were affected by osteoporosis, presumably secondary to an abnormality of mucopolysaccharides that cause progressive deterioration in the bones and cornea. However, many cases of SND reported in the literature appear idiopathic.
Patients who have SND typically present with complaints of foreign body sensation, but may also complain of epiphora, photophobia or slow, progressive blurring of vision. That said, patients who have SND may also be asymptomatic.
SND is diagnosed on discovery of gray-white to bluish raised subepithelial corneal lesions via slit lamp examination. These lesions typically are found in the peripheral to mid-peripheral cornea and may occasionally stain with fluorescein. On histological study, SND nodules show absent or broken Bowman’s layer that have overlying thinned epithelium and disorganized subepithelial collagen fibrils, and thick and tortuous branches of stromal nerves are found beneath SND nodules. Activated keratocytes also are found within the stroma posterior to the nodules, and elongated basal epithelial cells are seen at the peripheral edge of nodules. Deep stroma and endothelium are not affected in eyes that have SND. Of note: Corneal topography of SND eyes may reveal irregular astigmatism secondary to areas of raised lesions.
HOW TO TREAT IT
There is no spontaneous resolution of SND reported in the literature, however, medical management successfully treats the majority of patients.
To start, patients who have mild foreign body sensation may be managed with artificial tears used q.i.d. to as often as needed. A more viscous lubricant, such as a gel tear, may be needed for patients who have moderate to severe foreign body sensation. Treating concomitant ocular surface disease may also aid in symptom reduction, as dry eye issues compound the symptoms of SND. Therapies commonly used for concomitant dry eye and SND are topical corticosteroids dosed according to severity, cyclosporine (Restasis, Allergan) b.i.d., lifitegrast (Xiidra, Shire) b.i.d., as well as serum tears up to six times a day.
In patients who have reduced BCVA or who are unable to achieve relief via topical treatments, SK is the go-to surgery. The reason: It improves vision in 90% of cases and can be done as an in-office procedure at the slit-lamp, however, SND recurrences are common (as with this patient).
In patients who do not improve with SK, phototherapeutic keratectomy (PTK) with or without mitomycin C can be used as adjunctive therapy to smooth residual irregularities in Bowman’s layer or alleviate anterior corneal haze. That said, patients who undergo PTK should be counseled that it can induce a myopic shift. Rarely, anterior lamellar keratoplasty or penetrating keratoplasty may be required if Salzmann nodules extend to the mid-stroma, or if stromal haze is present after SK, as it and PTK can only treat the anterior cornea.
SND patients with chronic foreign body sensation or blur who want to avoid laser surgical correction with PTK may find SND symptom relief and improved vision via properly fitted scleral contact lenses that fully vault the cornea. This was our patient. She was fit in a scleral lens in the right eye (most affected by SND), which improved vision from 20/50 with monocular diplopia to 20/20. The patient was “20/happy” in her other eye, while uncorrected, and has chosen to only correct her vision in the right eye with a scleral lens, for now. OM