Salzmann's Nodular Degeneration of the Cornea

Abstract

Salzmann's nodular degeneration is a rare, noninflammatory, slowly progressive, degenerative condition. Bluish-white nodules raised above the surface of the cornea characterize it. It has usually developed in corneas with a history of phlyctenulosis, trachoma, vernal keratoconjunctivitis, measles, scarlet fever, and various other viral diseases. However, today the majority of cases have been seen without recognized previous keratitis. It is composed of dense irregularly arranged collagen tissue with hyalinization between epithelium and Bowman's layer or beyond. Manual removal, phototherapeutic keratectomy (PTK) with or without the use of topical mitomycin-C, lamellar or penetrating keratoplasty have been used in the treatment of this disease. Salzmann's nodular degeneration does not seem to consist of one clinical entity. In some cases, elevated and pannus-like tissue can be separated easily from the corneal surface leaving Bowman's layer almost untouched. In these eyes, subsequent PTK may be necessary to smooth the surface. Recurrences are rare in these eyes. In contrast, some eyes (often with major peripheral vascularization) are left with deep defects in Bowman's layer and superficial stroma after difficult mechanical removal of nodules. In these eyes, multiple masking/laser ablation procedures are mandatory to acquire a homogenous surface. In our experience, the required laser ablation depth is significantly greater and the best-corrected visual acuity to be expected is reduced in contrast to the eyes with easy removal of the nodules. In these eyes recurrences seem to occur more frequently after treatment. Of 35 eyes documented to have Salzmann's nodular degeneration during the last 15 years in our department, 22 needed PTK treatment. Visual acuity increased from 0.4 to 0.7 on average. As a routine, laser ablation should be combined with previous conventional removal of nodules and excessive pannus tissue. By doing so, lamellar and penetrating keratoplasty techniques are hardly ever required in those eyes.

Peripheral hypertrophic subepithelial corneal degeneration presenting with bilateral nasal and temporal corneal changes

“…However, our patients were on average younger and the geographic distribution of corneal opacities different from SN in that they were always bilateral and almost exclusively limited to the palpebral aperture. 11 Although such a pattern has been described for SN observed myopes with an extensive history of contact lens wear, only two of our patients had 'occasionally' used contact lenses years prior to initiation of symptoms. 11,12 The histopathologic findings in our patients were similar to those of pterygoid corneal dystrophy with a discontinuous basement membrane, absence/ fragmentation of Bowman's layer, subepithelial fibrovascular tisse, elastoid degeneration of collagen and elastic fibers, subepithelial hyalinisation of connective tissue, and epithelial cells expressing both cornea-(K12) and conjunctiva-specific markers (K13).…”

“…11 Although such a pattern has been described for SN observed myopes with an extensive history of contact lens wear, only two of our patients had 'occasionally' used contact lenses years prior to initiation of symptoms. 11,12 The histopathologic findings in our patients were similar to those of pterygoid corneal dystrophy with a discontinuous basement membrane, absence/ fragmentation of Bowman's layer, subepithelial fibrovascular tisse, elastoid degeneration of collagen and elastic fibers, subepithelial hyalinisation of connective tissue, and epithelial cells expressing both cornea-(K12) and conjunctiva-specific markers (K13). 7 This clinically also presents as a bilateral corneal opacification with nasal/temporal involvement and multiple relapses after pterygium surgery at young age and reduced visual acuity because of high irregular astigmatism.…”

Das okuläre «Neurothekeom» im Vexierbild der Differentialdiagnostik

“…Das therapeutische Vorgehen ist unumstritten und besteht aus einer Kombinationstherapie aus Alkoholabrasio, manuell superfizieller Keratektomie (BowmanMembran als Leitschiene), gegebenenfalls der Anwendung einer therapeutischen Excimer-Laserbehandlung zur Glättung der Oberfläche und der intraoperativen Anwendung von Mitomycin C [2][3][4][5][6]. Der hier geschilderte Fall ist eine absolute Rarität -bisher wurden in der Literatur nur 11 Fälle eines okulären Neurothekeoms beschrieben [7].…”

Salzmannsche noduläre Hornhautdegeneration

“…1 [16]. Andere sprechen in der Folge von "idiopathischen" Fällen [6], oder es wird formuliert "suggests a predominantly biologic rather than an environmental etiology" 2 [9]. Im Prinzip lässt sich all das als weitere Unterstützung unserer Dystrophie-Argumentationskette verwenden.…”