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A Brief Overview of Salzmann’s Nodular Degeneration and Its Topographical Outcomes

Home / External Disease and Cornea / Clinical Approach to Depositions and Degenerations of the Conjunctiva, Cornea, and Sclera

Author: Tanmay Majmudar, BS, MS4 at Drexel University College of Medicine

Photographer: James Gilman, CRA FOPS

Date: 9/12/2023

Keywords/Main Subject: cornea, corneal dystrophy, corneal topography, Salmann’s nodular degeneration, superficial keratectomy

Diagnosis: Salzmann’s Nodular Degeneration

Case Presentation:

A 64-year-old female was referred to the cornea clinic by an outside optometrist for progressively worsening vision in both eyes (OS worse than OD). She had a remote history of pterygium removal in both eyes, high astigmatism and hyperopia corrected with bifocal prescription glasses, and early dry stage nonexudative age-related macular degeneration. She also used preservative free artificial tears twice daily for chronic eye dryness and bedtime lubricant ointment as needed. Her past medical, family, and social histories were otherwise unremarkable.

Upon presentation to our clinic, her best corrected visual acuity (BCVA) with prescription bifocals was 20/40-1 and 20/60 in the right and left eyes respectively. Slit lamp examination of the anterior segment revealed a 2.5 mm greyish nodule (see a representative slit-lamp image from another patient with the same diagnosis in Figure 1) between the corneal epithelium and Bowman’s layer nasally over the pterygium scar in the right eye and a similar appearing 4 mm nodule nasally in the left eye as well. Trace to 1+ superficial punctate keratitis stable from prior exams was also noted in both eyes. The rest of the exam, including a dilated fundus exam, was unremarkable besides nuclear sclerotic cataracts (graded 2+) in both eyes.

Figure 1. Slit-lamp image of another patient with Salzmann’s nodular degeneration showing the characteristic blue-greyish nodules. Image taken by James Gilman, University of Utah John A Moran Eye Center.

Figure 1. Slit-lamp image of another patient with Salzmann’s nodular degeneration showing the characteristic blue-greyish nodules. Image taken by James Gilman, University of Utah John A Moran Eye Center.

Corneal Topography:

Atlas corneal topography was ordered to characterize the corneal nodules seen on slit-lamp examination, especially given the clinical history of astigmatism. Figure 2 shows a Zeiss Atlas report of the patient for both eyes with an axial curvature map and Placido disc-based “rings image”. Topography in the left eye shows a high irregular astigmatism with focal steepening and irregular mires noted in the superotemporal region. A crab-claw like pattern of irregular astigmatism is more noticeable nasally in the right eye. These focal areas of astigmatism largely correspond to the location of the blue-grayish nodules noted on slit-lamp examination.

 

Figure 2. Pre-operative corneal topography.

Figure 2. Pre-operative corneal topography.

Diagnosis:

A diagnosis of Salzmann’s nodular degeneration (SND) was made on the basis of the characteristic appearance on slit-lamp examination, clinical history of bilateral, gradually progressive, painless visual decline, history of prior ocular surface surgery (pterygium removal) and chronic dry eyes, and high irregular astigmatism noted on corneal topography corresponding to areas of nodular growth.

Treatment & Clinical Course:

To improve visual acuity and to reduce the high irregular astigmatism, a superficial keratectomy (SK) was recommended to remove the Salzmann’s nodules; however, the patient was informed that refractive outcomes may not eliminate her astigmatism and that recurrence of these nodules was possible.

Post-Operative Outcomes:

About two weeks after her initial presentation to the cornea clinic, the patient underwent SK on her left eye. At the time of writing, post-operative refractive and topographical data for the patient’s right eye (surgery completed about two weeks after the left eye) are unavailable. Two months postoperatively, her left cornea’ epithelium healed with complete clearing of the subepithelial opacities. Post-operatively her left eye achieved a best corrected visual acuity of 20/20 -2, with substantial reduction in astigmatic error (Figure 3, Table 1).

Table 1. Pre- and post-operative refraction in a patient with Salzmann’s nodular degeneration.

Pre-operative Manifest Refraction (OS)
-0.25 + 1.50 x 045 VA 20/60
Post-operative Manifest Refraction
-0.50 + 1.00 x 030           VA 20/20 -2
Figure 3. Left eye topography before (top row) and after (bottom row) superficial keratectomy for removal of Salzmann’s nodules. After intervention, topography shows a more spherical cornea with substantially more regular mires and corresponding reduction in both regular and irregular astigmatism from 5.36 diopters to 1.00 D.

Figure 3. Left eye topography before (top row) and after (bottom row) superficial keratectomy for removal of Salzmann’s nodules. After intervention, topography shows a more spherical cornea with substantially more regular mires and corresponding reduction in both regular and irregular astigmatism from 5.36 diopters to 1.00 D.

Discussion:

Salzmann’s Nodular Degeneration (SND) is an unusual and relatively rare1 disorder of the cornea that involves the growth of blue-grayish fibrous corneal opacities of various sizes (typically 1-3 mm) anterior to the Bowman’s capsule2. It is a slowly progressive, noninflammatory degenerative condition that typically affects middle-aged Caucasian females (between ages 50-60)2,3 and occurs bilaterally3. Though many patients with SND are asymptomatic early in their disease course, gradually decreasing visual acuity due to irregular astigmatism, hyperopic shifts, or mechanical tear film disturbances is the most common presenting symptom3-5. Other symptoms are related ocular surface irritation, including foreign body sensation, pain, tearing, blepharospasms, or recurrent corneal erosions are also reported2,3,6.

The precise mechanism of this degeneration is poorly understood. Mechanical disruption between the corneal epithelium and stroma from chronic ocular surface inflammatory conditions such as dry eye, meibomian gland dysfunction (MGD), long-term contact lens wear, keratoconjunctivitis sicca, exposure keratitis, pterygium amongst others have been implicated in prior studies2,3,6-9. SND has also been observed in the setting of previous ocular surgery and trauma, such as after LASIK5,10, cataract extraction11, radial keratotomy12, and corneal transplants13. Our patient’s history of chronic eye disease, pterygium removal, and long-term contact lens wear also supports the pathogenic role of these risk factors in the development of SND. Finally, prior studies have documented associations between systemic inflammatory conditions, such as Crohn’s disease14, and SND while others have also attempted to elucidate a genetic involvement15.

Diagnosis of SND is usually made based on a careful examination of corneal structure under slit-lamp biomicroscopy. Nodules appear as blueish-white to grayish-yellow subepithelial elevations that may occasionally stain with fluorescein2. While diagnosis of SND is primarily based on slit-lamp examination findings and the clinical history, it may be supported by corneal topography, as in this patient, or high-frequency ultrasound biomicroscopy, in-vivo confocal microscopy, and optical coherence tomography of the anterior segment. Classic histologic features include a thinned epithelium overlying the nodules, fragmented or absent Bowman’s membrane, or stromal scarring2,16. Unfortunately, these histologic features of non-specific and can frequently be seen with old corneal scars from trauma or inflammation.

Management options are largely driven by the severity of symptoms. Although asymptomatic patients are primarily observed, treatment of mild disease is aimed at addressing the underlying etiology through medical management. Use of preservative-free lubricant eye drops, lid hygiene, and warm compresses in patients with chronic dry eye has been effective in the majority of cases3.  Medical options to treat SND associated with chronic ocular inflammation include steroids, NSAIDs, cyclosporine and doxycycline amongst others2. If nodules occur in the setting of contact lens use, then reduction of use or cessation may also relieve symptoms. However, in cases that do not respond to conservative management or those patients with visually significant nodules, surgical management is necessary.

A variety of surgical options exist, including SK, otherwise known as Salzmann nodulectomy, phototherapeutic keratectomy (PTK), lamellar or penetrating keratoplasty. Of these, SK is the most common method for nodule removal. Briefly, the epithelium overlying the nodules is removed and the nodular edge is simply peeled off the corneal surface with forceps or a flat blade, leaving Bowman’s layer almost untouched2. Post-operative outcomes are very favorable in reducing astigmatic error and improvements in visual acuity have been recorded in 79.2%-100% of patients in prior studies2,3,6. In rare cases, persistent anterior stromal haze may necessitate further treatment with PTK. Rarely, lamellar or penetrating keratoplasty may be required for patients with concurrent corneal pathologies involving the deeper stroma and endothelium. Although varying rates of recurrences have been reported3,6,7, visually significant recurrences are uncommon (ranging from 5 to 20%) and can be further minimized with management of the underlying etiologies3,6.

Beyond the visual limitations of corneal nodularity itself, the accuracy of keratometry and biometry calculations, a critical step in selecting the appropriate intraocular lens (IOL), is largely based on a clear cornea with a smooth regular surface. Patients with corneal dystrophies, such as SND or epithelial basement membrane dystrophy, have irregular corneas that can such adversely affect biometry, recommended IOL choice, and postoperative visual outcomes. In patients requiring cataract surgery who also have comorbid corneal irregularities, prior studies have showed improved reliability in biometry measurements after management with SK and better post-cataract optical quality17,18. Although our patient, with 2+ nuclear sclerotic cataracts, continues to deny visually limiting symptoms related to them, this case nonetheless highlights the importance of addressing the refractive sequelae of SND in consideration for future cataract surgery.

References:

  1. Gupta PK, Drinkwater OJ, VanDusen KW, Brissette AR, Starr CE. Prevalence of ocular surface dysfunction in patients presenting for cataract surgery evaluation. J Cataract Refract Surg. Sep 2018;44(9):1090-1096.
  2. Hamada S, Darrad K, McDonnell PJ. Salzmann’s nodular corneal degeneration (SNCD): clinical findings, risk factors, prognosis and the role of previous contact lens wear. Cont Lens Anterior Eye. Aug 2011;34(4):173-8.
  3. Graue-Hernández EO, Mannis MJ, Eliasieh K, et al. Salzmann nodular degeneration. Cornea. Mar 2010;29(3):283-9.
  4. Oster JG, Steinert RF, Hogan RN. Reduction of hyperopia associated with manual excision of Salzmann’s nodular degeneration. J Refract Surg. Jul-Aug 2001;17(4):466-9.
  5. VanderBeek BL, Silverman RH, Starr CE. Bilateral Salzmann-like nodular corneal degeneration after laser in situ keratomileusis imaged with anterior segment optical coherence tomography and high-frequency ultrasound biomicroscopy. J Cataract Refract Surg. Apr 2009;35(4):785-7.
  6. Farjo AA, Halperin GI, Syed N, Sutphin JE, Wagoner MD. Salzmann’s nodular corneal degeneration clinical characteristics and surgical outcomes. Cornea. Jan 2006;25(1):11-5.
  7. Das S, Langenbucher A, Pogorelov P, Link B, Seitz B. Long-term outcome of excimer laser phototherapeutic keratectomy for treatment of Salzmann’s nodular degeneration. J Cataract Refract Surg. Jul 2005;31(7):1386-91.
  8. Vannas A, Hogan MJ, Wood I. Salzmann’s nodular degeneration of the cornea. Am J Ophthalmol. Feb 1975;79(2):211-9.
  9. Yoon KC, Park YG. Recurrent Salzmann’s nodular degeneration. Jpn J Ophthalmol. Jul-Aug 2003;47(4):401-4.
  10. He X, Donaldson KE. Superficial keratectomy for Salzmann nodular degeneration following laser in situ keratomileusis. Can J Ophthalmol. Jun 2019;54(3):e149-e151.
  11. Qiu J, Cai R, Zhang C. Association between poor wound healing and the formation of Salzmann nodules. J Cataract Refract Surg. Oct 2016;42(10):1527-1530.
  12. Fong YC, Chuck RS, Stark WJ, McDonnell PJ. Phototherapeutic keratectomy for superficial corneal fibrosis after radial keratotomy. J Cataract Refract Surg. Apr 2000;26(4):616-9.
  13. Geggel HS. Effect of peripheral subepithelial fibrosis on corneal transplant topography. J Cataract Refract Surg. Jan-Feb 1996;22(1):135-8.
  14. Roszkowska AM, Spinella R, Aragona P. Recurrence of Salzmann nodular degeneration of the cornea in a Crohn’s disease patient. Int Ophthalmol. Apr 2013;33(2):185-7.
  15. Papanikolaou T, Goel S, Jayamanne DG, Mudhar H, Desai SP. Familial pattern of Salzmann-type nodular corneal degeneration–a four generation series. Br J Ophthalmol. Nov 2010;94(11):1543.
  16. Stone DU, Astley RA, Shaver RP, Chodosh J. Histopathology of Salzmann nodular corneal degeneration. Cornea. Feb 2008;27(2):148-51.
  17. Goerlitz-Jessen MF, Gupta PK, Kim T. Impact of epithelial basement membrane dystrophy and Salzmann nodular degeneration on biometry measurements. J Cataract Refract Surg. Aug 2019;45(8):1119-1123.
  18. Kim BZ, Wilson PJ, McGhee CN. Annular Salzmann degeneration: Avoiding perturbations and pitfalls in phacoemulsification surgery. J Cataract Refract Surg. Nov 2015;41(11):2580-3.

Faculty Approval By: Brian Zaugg, MD & Griffin Jardine, MD

Copyright: Tanmay Majmudar, ©2023. For further information regarding the rights to this collection, please visit: http://morancore.utah.edu/terms-of-use/