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Salzmann's nodular corneal degeneration (SNCD): Clinical findings, risk factors, prognosis and the role of previous contact lens wear
Contact Lens & Anterior Eye 34 (2011) 173–178
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Contact Lens & Anterior Eye journal homepage: www.elsevier.com/locate/clae
Salzmann’s nodular corneal degeneration (SNCD): Clinical findings, risk factors, prognosis and the role of previous contact lens wear Samer Hamada ∗ , Kanupriya Darrad, Peter J. McDonnell Birmingham and Midland Eye Centre, City Hospital, Dudley Road, Birmingham B187QH, UK
a r t i c l e Keywords: Salzmann’s Nodular Degeneration Soft contact lens Prognosis Risk factors
i n f o
a b s t r a c t Purpose: To revisit the clinical presentations of Salzmann’s nodular corneal degeneration (SNCD) and to identify risk factors, occurrence and prognosis, and in particular to assess the role of previous contact lens wear as an aetiological factor. Methods: Retrospective case note review of all cases of Salzmann’s nodular degeneration over the last twenty years. We analysed epidemiological features, characteristics of lesions, risk factors and final outcomes. Results: Thirty eyes (19 patients) were identified with SCND. Eleven patients had bilateral disease. Our cohort included 14 female (73.7%) and 5 males (26.3%). Average age at presentation was 58.9 (range 30–75) years. Follow up range was 0–13 years. The most common presenting symptom was foreign body sensation (68.4%). Ocular pathologies were: dry eyes (56%), chronic blepharitis (32%), trichiasis (8%), trachoma (32%), previous ocular trauma (8%), and previous ocular surgery (21.4%). Sixteen percent of cases were soft monthly disposable contact lens wearers. None of our patients with rigid contact lens wear developed Salzmann’s nodules. Surgical excision was needed in 4 cases (13.3%). Two of them developed recurrent disease. Conclusion: Salzmann’s nodular corneal degeneration is a disorder affecting middle-aged white women predominantly, and seems to be associated with concomitant chronic MGD, dry ocular surface, soft contact lens wear and previous ocular surgery. The prognosis is very good, and most patients are “successfully” treated with medical management alone, and therefore correct diagnosis of the disease is paramount. If indicated, various surgical options are available and give good outcomes. However, Salzmann’s nodules can recur after penetrating keratoplasty. © 2011 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.
1. Introduction Salzmann’s nodular corneal degeneration (SNCD) is a worldwide occurring, relatively rare, non-inflammatory, slowly progressive disease originally described by Maximilian Salzmann in 1925 [1]. However, Ernst Fuchs may have made the initial case observation in 1901 [2]. SNCD is classically described as bluish-greyish nodular corneal opacities of various sizes (mostly 1–3 mm) occurring in isolation or in multiple numbers anywhere on the cornea (Fig. 1(a–b)). Salzmann’s nodules can occasionally take up fluorescein staining (Fig. 2). Histopathological findings involve thinning or denudation of the epithelium, destruction of Bowman’s layer, duplication of the epithelial basement membrane and disorganisation of collagen lamellae in the superficial anterior stroma. These histological findings are entirely non-specific and can be seen in scarring
∗ Corresponding author. Tel.: +44 (0) 7808174099. E-mail address: [email protected] (S. Hamada).
from any cause. The cause of the degeneration is uncertain and still debated upon [3], but associations with chronic ocular irritation and inflammation have been made. It may be idiopathic; however it is often associated with pre-existing corneal disease. SNCD has been associated with trachoma, interstitial keratitis, vernal keratoconjunctivitis, phlyctenular keratoconjunctivitis, ocular trauma, corneal exposure, measles, scarlet fever, and previous ocular surgery. The purpose of this study is to revisit the clinical presentations of SNCD and to identify risk factors, occurrence and prognosis. In particular, the role of previous contact lens wear in the development of SNCD will be investigated.
2. Patients and methods Retrospective case note review of all cases of Salzmann’s nodular degeneration that we have identified in our centre (Birmingham and Midland Eye Centre) over the last twenty years (March 1990–April 2010). We analysed epidemiological features, characteristics of lesions, risk factors and final outcomes.
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Fig. 1. (a–b) Salzmann’s nodules appear as bluish-white nodules raised above the surface of the cornea. It can be single, multiple (separated or confluent).
females (73.7%) and 5 males (26.3%). Average age at presentation was 58.9 (range 30–75) years. Follow up period varied according to initial presentation, severity, and progression of the disease; and ranged from 0 to13 years. More than half of patients were white Caucasian (11/19). The remaining were Asian (7/19) and Afro-Caribbean (1/19). Demographical data are summarised and compared with other studies in Table 1. Eleven patients had bilateral disease. Salzmann’s nodule distribution varied among patients. All eyes had peripheral corneal nodules. 10% of all eyes had lesions in the central cornea involving visual axis. We looked at the distribution of corneal lesions, which were as follows: super-nasal quadrant 28.2%, super-temporal quadrant 23%, infra-nasal quadrant 20.5%, infra-temporal quadrant 17.9%, and central cornea 10.3%. All of which were not statistically significant (Table 1). Central corneal nodules were seen in the eyes of Asian females who also showed signs of ocular surface trachoma. These females had both eyes affected with SCND but only one eye manifested Salzmann nodules in the central cornea. Peripheral corneal vascularisation (360◦ ) was seen in one patient (two eyes) who had bilateral disease and a history of bilateral penetrating keratoplasties. Penetrating keratoplasties were performed to treat severe corneal scarring from herpes simplex keratitis. The majority of patients (68.4%) complained of foreign body sensation. Other symptoms included “white spots on cornea” (5.3%) and reduced vision (5.3%). However, 15.8% were asymptomatic and referred by their optometrist to exclude the presence of treatable corneal disease (Table 1). We looked at other ocular pathologies that were documented at the time of first presentation and these included: dry eyes (56%), chronic blepharitis (32%), trichiasis (8%), trachoma (32%), previous ocular trauma (8%), previous ocular surgery (21.4%) of which 8% were post pterygium surgery (Table 1). We identified that 16% of cases were soft monthly disposable contact lens wearers but they had no other ocular pathology. None of our patients with rigid contact lens wear developed Salzmann’s nodules. Management of SNCD involved: ocular lubrication (66%), topical anti-inflammatory (33%) mainly Prednisolone 0.5% eye drops, and surgical excision in 4 cases (13.3%). Two underwent penetrating keratoplasties, one had simple surgical excision, and one had anterior lamellar keratoplasty. The disease has recurred in two patients (2 eyes), both had penetrating keratoplasty. Finally, we reported final visual outcomes i.e. visual acuities measured at last hospital visit: 21 eyes ≥ 6/9, 1 eye = 6/12, and 4 eyes ≤ 6/36 (all trachoma cases). No visual acuities data at last visit for 4 eyes.
4. Discussion
Fig. 2. Cobalt blue light shows fluorescence staining of Salzmann’s nodules.
3. Results Thirty eyes (19 patients) were identified with the clinical diagnosis of Salzmann’s nodular degeneration. Our cohort included 14
Originally Salzmann described 23 patients with bluish-white corneal lesions, 18 of whom were females [1]. Later studies by Farjo et al. and Graue-Hernandez et al. [2,3] supported Salzmann observations that SNCD affect mainly middle aged females. Our cohort reflected the same trend; 73.7% of our patients were females and the average age was 58.9 years (30–75). Furthermore, our study showed a preponderance of SNCD to affect the white population (57.9%). Graue-Hernandez reported the majority of his cases were white (76.1%) in a group where the total white population was only 47.8% [3]. However he suggested that access to medical care may have been more readily available to certain populations, which can introduce bias in the study sample. Therefore, more studies are needed to support these findings. As the majority of the patients in our study were middle aged females and older males, and the commonest associations with SNCD were dry ocular surface (56%), chronic meibomian gland dysfunction (MGD) 32%, it can be postulated that there may be an
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Table 1 Comparision of our results with those by Graue-Hernandez et al. [3] and Farjo et al. [2]. Variables
Our study
Graue-Hernandez et al. [3]
Farjo et al. [2]
Gender
Male: 26.3% Female: 73.7% 57.9 58.9 30–75 0–156 White Caucasuian: 57.9 Asian (Indian): 36.8 Afro-Caribbean: 5.2 Foreign body sensation: 68.4% Asymptomatic: 15.8% Reduction in visual acuity: 5.3% Dry eyes – 56% MGD – 32% Trachoma – 32% Contact lens wear – 16% Previous ocular surgery – 21.4% Peripheral (90%) Peripheral and central (10%) (one eye in bilateral disease) 6.6% (360◦ vascularisation) 4/30 eyes
Male: 27.8% Female: 72.2% 66.7 60.8 13–92 0–357 White Caucasian: 76.1
Male: 11.8% Female: 89.2% 63.4 54.3
Reduction in visual acuity: 30%
Reduction in visual acuity
MGD – 41.7%
MGD – 54.8% Contact lens wear – 33.3% Pterygium excision – 16%
Not stated 41/ 180 eyes
31.2% 49/152 eyes
Reduction in vision and ocular discomfort in all cases
Reduction in vision (commonest)
100% of patients with improvement in visual acuity
90.2% of patients
Reduction in vision (85.7%) Ocular discomfort (8.2%) Contact lens intolerance (6.1%) 79.2% of patients with improvement in visual acuity 100% of patients with reduced ocular discomfort
Bilateral disease (%) Mean age (years) Range of age (years) Follow up time range (months) Race (%)
Commonest symptoms at presentation
Commonest ocular co-morbidities
Location of lesions
Peripheral corneal vascularization Surgical treatment (PK or lamellar keratoplasty) Indicators for surgery
Successful surgical outcome (improvement in visual acuity)
Visual axis involvement – 30%
Recurrence of disease in 21.9% of patients Visual acuities at last visit
Lesions distribution
Not stated
4 < 6/36 (trachoma cases) 1 = 6/12 21 ≥ 6/9 4 Unknown Super-nasal quadrant 28.2% Super-temporal quadrant 23% Infra-nasal quadrant 20.5% Infra-temporal quadrant 17.9% Central cornea 10.3%
influence of changing levels of female and male sex hormones. Androgen deficiency can lead to MGD and subsequent evaporative dry eye and reduced tear production. This leads to poor epithelial protection which as mentioned earlier is thought to be a promoting factor for SNCD [4,5]. 4.1. Clinical features SNCD was bilateral in 57.9% of cases, with similar figures described by Farjo et al. [2], and Graue- Hernandez [3]. All our cases had peripheral corneal nodules, of which three involved the visual axis (peripheral nodules (90%), peripheral and central nodules (10%)). This may explain why the commonest presenting complaint in this study was of foreign body sensation (68.4%) as opposed to a decrease in visual acuity (5.3%), which was noted to be the commonest presentation in some other studies. The association of peripheral corneal vascularisation and SNCD was explored in this study, however only 2 eyes (one patient) out of 30 eyes with SNCD had peripheral vascularisation. This patient had chronic viral keratitis and a history of bilateral penetrating keratoplasties; therefore the original pathology could be responsible for the development of corneal vascularisation. Farjo [2] had demonstrated that 33.6% of eyes with SNCD had peripheral corneal vascularisation but there is no mention of whether this association was statistically significant. Recurrent corneal erosion is reported to be a possible consequence of SNCD, however this has not been observed this in any of our patients [2]. The three most common ocular pathologies associated with SNCD were dry eyes (56%), chronic blepharitis (32%), and trachoma
(32%). Blepharitis was the main ocular co-morbidity in studies by Farjo et al. and Graue-Hernandez et al. (54.8% and 41.7% respectively) [2,3]. Trachoma was the most common ocular co-morbidity in our non-Caucasian group. The trachoma sub-group which comprised patients belonging to the South Asian race only, did show a tendency to have bilateral, central corneal, and recurrent disease. All cases that needed surgery were among this group, and had poor final visual outcomes. 4.2. Formation of salzmann’s nodules There is no uniform theory to explain how Salzmann’s nodules are formed. Abbott and Forster [6] have postulated that hyaline degeneration might be a precursor of the disease. Yoon and Park [7] have further described hyaline plaques between corneal epithelium and Bowman’s layer. They suggest that histological findings are not different from a degenerative pannus or an old corneal scar following trauma or inflammation. However another possible theory suggested by Yoon and Park which requires further investigation is one of an active immune process playing a role in the pathogenesis of SNCD after detection of B and T Lymphocytes and Major Histocompatibility Complex class II antigen in histopathalogical examination of corneal specimens [7]. Furthermore, an important promoting factor for SNCD is thought to be external irritation because of poor epithelial protection. This provides the stimulus for the overgrowth of fibroblasts, eventually leading to the formation of nodules. Chronic exposure to sunlight and environmental irritants can cause hyaline changes in the nodules by precipitation of
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ground substance onto the collagen fibres [7–9]. Stone et al. have described an increase in matrix metalloproteinase-2, sub epithelial fibrosis, and disrupted Bowman’s membrane suggesting that the nodules may result from longstanding epithelial remodelling and wound repair [10]. This may support the findings in our study where the commonest associations with SNCD were blepharokeratoconjunctivitis, dry ocular surface, and a history of contact lens wear. 4.3. Contact lenses wear and SNCD We identified that 16% of cases were monthly disposable soft contact lens wearers but had no other ocular pathology. None of our patients with rigid contact lens wear developed Salzmann’s nodules. Farjo et al. [2] reported that 33.3% of SNCD cases were contact lens wearer. It is possible that the increase use of contact lenses in population has highlighted contact lens wear as a risk factor for the development of SNCD, presumably as a result of constant CL-related cornea irritation. Contact lens wear has been associated with significant corneal epithelium thinning, lower levels of oxygen uptake, as well as increase in corneal epithelial micro cysts, thinner stroma and an increase in significant levels of daytime corneal oedema [11,12]. As suggested by Yoon and Park that poor corneal epithelial protection can be a stimulus for the development of Salzmann nodules, it is important to highlight the effects of contact lens on the corneal epithelium which leads to poor epithelial protection. These factors are: (1) Stem cell turnover: contact lens wear slows down stem cell turnover and thus reducing corneal epithelial renewal [13]. (2) Corneal homeostasis: extended wear with all types of soft or rigid gas permeable lenses results in significant reduction in the rate of exfoliation of central corneal epithelium. Combined with the suppression of epithelial cell proliferation, migration, and a reduction of epithelial cell exfoliation, the corneal epithelial cell turnover is significantly slowed down in contact lens wear. These processes may be mediated by lens-induced hypoxia. Another theory is suppression of apoptosis-driven cell death seen in corneal epithelium after contact lens wear by the constant expression of Bcl-2 at the corneal surface (an antiapoptotic protein) [14]. (3) Physical presence of contact lenses which lift the lid away from the cornea leading to poor tear film stability with subsequent drying of the cornea. This is often exacerbated by incomplete blinking. A small amount of staining (at the 3- and 9-o’clock positions) is benign, but persistent epithelial erosions can lead to dellen formation, neovascularisation, Salzmann-type elevated lesions, and pseudo-pterygium formation. In fact, SNCD seen in contact lens wearer were noted in the interpalpebral fissure. This type of punctate staining is alleviated by using a larger lens, reducing edge lift with a thinner-edged lens or steeper fit, or by refitting a lens that rests under the upper lid. (4) It has been postulated that Salzmann’s nodules appear in dry eye patients who wear contact lenses. Those patients often have areas of localised drying that lead to Salzmann’s scarring [15]. Reduced corneal thickness and increased cornea surface irregularity occur after both soft and RGP contact lenses [16]. To our knowledge, SNCD has not been reported in rigid gas permeable (RGP), or scleral contact lens wearers. We propose that RGP lenses induce less ocular surface inflammation and irritation. Corneal punctate staining is seen more in soft lenses compared with rigid lenses. Soft contact lens wearer with symptoms of mild irritation or slightly decreased vision usually benefit from refitting
with a higher water content or RGP lenses. Moreover, epithelial splitting is a common finding in asymptomatic soft contact lens wearers. This finding often is overlooked on a routine examination because it usually does not cause severe symptoms and may be covered by the upper lid. The splits usually heal after the lens has been removed for 24 h, and refitting with RGP lenses prevents recurrence. Furthermore, contact lens induced superior limbal keratitis may be caused by excessive lens movement or sensitivity to thimerosal. The treatment consists of discontinuing contact lens wear until the epithelium returns to normal and the symptoms resolve. Refitting with better fitting lenses, using preservativefree solutions with a hydrogen peroxide disinfecting system, or switching to rigid gas-permeable (RGP) contact lenses may permit a resumption of contact lens wear. Ichijima at al. found out that epithelial barrier functions are more affected in soft contact lens wear compared to rigid gas permeable contact lenses wear [17]. Finally, the prevalence of neovascularisation is low with RGP or PMMA contact lenses, more common with daily wear soft contact lenses, higher with extended-wear soft contact lenses, and very high with aphakic extended-wear lenses. Extended wear of RGP lenses usually induces less central oedema than extended wear of soft hydrogel contact lenses. Confocal microscopy has helped to identify a novel type of stromal change which is chronic in nature, displaying highly reflective panstromal microdot deposits in the corneal stroma. This deposition is more common with long-term wear of contact lenses and more common with soft lenses than with RGP lenses [18]. 4.4. Management Recognition of this disorder is very important as it has a good prognosis with conservative and surgical management. Management of underlying condition is an essential part of disease control, and this was part of our protocol plan in managing patients with SCND. Symptoms related to SCND and progression of the condition may be helped by reducing or stopping contact lens wear, reviewing the fit of the contact lenses, and by providing plentiful preservative free ocular lubrication. As the condition stabilises and symptoms improve, it may be possible to cautiously resume contact lens wear but the patient should be carefully monitored for further problems or progression. In some patients superficial keratectomy can be helpful to remove very prominent and symptomatic lesions as discussed further below. The majority of our patients had nonsymptomatic inflammation accompanying scarring that show a favourable response to medical management alone. Conservative management consisted of eye lubrication, warm compresses, lid hygiene, topical steroids, and/or oral doxycycline. All patients were initially treated with ocular lubricants (preservative free). Topical steroids were needed occasionally to treat ocular surface inflammation when present. Where nodules were raised, located on the central visual axis, or particularly symptomatic, conservative treatment failed to control symptoms and therefore surgery was the next option (less than 10% of cases). The simplest method is to peel off a nodule, which is referred to as Salzmann nodulectomy (Graue-Hernández et al.). This is normally done in theatre under the microscope. Corneal epithelium is removed locally over the nodule and the nodule is then easily peeled off with forceps. Alternatively, Superficial keratectomy, lamellar or penetrating keratoplasty can be performed depending on the extent and depth of stromal involvement of the corneal nodules [19]. Excimer laser (photo therapeutic keratectomy PTK) has been used to smoothen out the surface after removal of Salzmann’s nodules [20–22]. As one would expect, PTK induced myopic shift [23,24]. In our series, four eyes needed surgical
S. Hamada et al. / Contact Lens & Anterior Eye 34 (2011) 173–178
management. Indication for surgery was reduction in visual acuity and ocular discomfort despite being on medical treatment. One eye had simple excision of lesions, another eye underwent anterior lamellar keraroplasty, and two eyes (trachoma cases) underwent penetrating keratoplasties because of associated deep stromal opacity. Both cases had improvement in vision and relief of ocular discomfort post surgery. However, recurrence of SNCD happened in two cases that had penetrating keratoplasties. These were later treated conservatively. Previous studies have shown that the most common reason to progress towards surgical management was disturbance in vision [3,21,25]. As SNCD does not seem to consist of one clinical entity, in some cases elevated and pannus-like tissue can be manually separated from the corneal surface leaving Bowman’s layer almost untouched. In these cases subsequent photo therapeutic keratectomy (PTK) may not be necessary to smooth the surface [19]. In other cases, deep defects are left in the Bowman’s layer and in the superficial stroma after difficult mechanical removal of the nodules, which then require multiple laser ablation procedures to acquire a homogenous surface. Cauterisation of the nodules is not advisable as it may lead to corneal opacification. Penetrating or lamellar Keratoplasty may be effective in cases where the lesion extend to the mid-stroma. As patient normally has a healthy uninvolved endothelium, penetrating keratoplasty (PK) is
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generally not recommended, unless other concurrent pathologies involve the deeper stroma and endothelium. The majority of Salzmann’s nodules involve the superficial cornea; hence the preferred option is Superficial Keratectomy, especially for sub epithelial lesions within visual axis or for mid peripheral lesions inducing astigmatism [19,21,25]. 4.5. Recurrent SNCD Recurrences have been reported several years after lamellar or penetrating keratoplasty [26,27]. In our study, there were two cases of recurrent SNCD post PK where the nodules appeared on the junction of the host and donor cornea (Fig. 3(a–b)). In one case recurrent corneal nodules appeared as early as two months after the surgery. In addition to the original causes of Salzmann’s nodule formation, immune reaction in the graft can contribute to the recurrence of Salzmann’s nodules [26]. Multifactorial processes lead to corneal surface alterations, dryness, and development of epithelial defects, which may lead to scarring in Bowman’s membrane resulting in a flat opacity, eventually giving rise to characteristic nodules of Salzmann’s degeneration afterwards. Recurrence of SNCD may manifest long time after the initial surgery because the underlying aetiology may still be present despite removal of nodules and elimination of ocular surface irritation or inflammation. Long term follow up results are needed to quantify the risk of disease recurrence. Controlling post-operative ocular inflammation is a key factor to reduce the risk of recurrent disease. Yoon and Park described a case of SNCD where superficial keratectomy was performed in conjunction with amniotic membrane graft in order to prevent inflammation, scarring, and vascularisation [2]. Whereas, Bowers et al. performed superficial keratectomy with mitomycin-C (MMC 0.4 mg/ml) application and reported no recurrence of the disease in the follow up period 28 ± 15 months [21]. Therefore, superficial keratectomy seems to give a stable, successful, predictable results as well as being an economical method of preventing and treating recurrence [19]. Additional procedures can enhance results and reduce risk of disease recurrence [7,21]. 5. Conclusion Salzmann’s nodular corneal degeneration is a disorder affecting middle-aged white women predominantly, and seems to be associated with concomitant chronic MGD, dry ocular surface, soft contact lens wear and previous ocular surgery. The prognosis is very good, and most patients are “successfully” treated with medical management alone, and therefore correct diagnosis of the disease is paramount. Surgical treatment results in good outcomes (improved visual acuity and relief of ocular irritation), however recurrence is possible especially after penetrating keratoplasty. Further studies with longer follow up times are required to determine the frequency of recurrence of the disease. References
Fig. 3. (a–b) Recurrent Salzmann’s nodules on corneal graft. This patient underwent penetrating keratoplasty for SNCD. She developed recurrent nodules soon after the surgery. Initially recurrent nodules were noted at graft–host interface; however, these have later increased in number and size over time.
[1] Salzmann M. Uber eine Abart Knotchenformigen Hornhautdystrophie. Ztschr Augenheilkd 1925;57:92. [2] Farjo AA, Halperin GI, Syed N, Sutphin JE, Wagoner MD. Salzmann’s nodular corneal degeneration clinical characteristics and surgical outcomes. Cornea 2006;25:11–5. [3] Graue-Hernandez EO, Mannis MJ, Eliasieh K, Greasby TA, Beckett LA, Bradley JC, et al. Salzmann nodular degeneration. Cornea 2010;29:283–9. [4] Mathers WD, Stovall D, Lane JA, Zimmerman MB, Johnson S. Menopause and tear function: the influence of prolactin and sex hormones on human tear production. Cornea 1998;17:353–8. [5] Sullivan DA, Sullivan BD, Evans JE, Schirra F, Yamagami H, Liu M, et al. Androgen deficiency, Meibomian gland dysfunction, and evaporative dry eye. Ann NY Acad Sci 2002;966:211–22.
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[6] Abbott RL, Forster RK. Superficial punctate keratitis of Thygeson associated with scarring and Salzmann’s nodular degeneration. Am J Ophthalmol 1979;87:296–8. [7] Yoon KC, Park YG. Recurrent Salzmann’s nodular degeneration. Jpn J Ophthalmol 2003;47:401–4. [8] Vannas A, Hogan MJ, Wood I. Salzmann’s nodular degeneration of the cornea. Am J Ophthalmol 1975;79:211–9. [9] Frising M, Pitz S, Olbert D, Kriegsmann J, Lisch W. Is hyaline degeneration of the cornea a precursor of Salzmann’s corneal degeneration? Br J Ophthalmol 2003;87:922–3. [10] Stone DU, Astley RA, Shaver RP, Chodosh J. Histopathology of Salzmann nodular corneal degeneration. Cornea 2008;27:148–51. [11] Stapleton F, Stretton S, Papas E, Skotnitsky C, Sweeney DF. Silicone hydrogel contact lenses and the ocular surface. Ocul Surf 2006;4:24–43. [12] Holden BA, Sweeney DF, Vannas A, Nilsson KT, Efron N. Effects of long-term extended contact lens wear on the human cornea. Invest Ophthalmol Vis Sci 1985;26:1489–501. [13] Cavanagh HD. The effects of low- and hyper-Dk contact lenses on corneal epithelial homeostasis. Ophthalmol Clin North Am 2003;16:311–25. [14] Ladage PM, Ren DH, Petroll WM, Jester JV, Bergmanson JP, Cavanagh HD. Effects of eyelid closure and disposable and silicone hydrogel extended contact lens wear on rabbit corneal epithelial proliferation. Invest Ophthalmol Vis Sci 2003;44:1843–9. [15] DB G. New approaches to old nodule problem. Eye World 2005. [16] Liu Z, Pflugfelder SC. The effects of long-term contact lens wear on corneal thickness, curvature, and surface regularity. Ophthalmology 2000;107: 105–11.
[17] Ichijima H, Yokoi N, Nishizawa A, Kinoshita S. Fluorophotometric assessment of rabbit corneal epithelial barrier function after rigid contact lens wear. Cornea 1999;18:87–91. [18] Liesegang TJ. Physiologic changes of the cornea with contact lens wear. CLAO J 2002;28:12–27. [19] Das S, Link B, Seitz B. Salzmann’s nodular degeneration of the cornea: a review and case series. Cornea 2005;24:772–7. [20] Hersh PS, Spinak A, Garrana R, Mayers M. Phototherapeutic keratectomy: strategies and results in 12 eyes. Refract Corneal Surg 1993;9:S90–5. [21] Bowers PJJ, Price MO, Zeldes SS, Price FWJ. Superficial keratectomy with mitomycin-C for the tratment of Salzmann’s nodules. J Cataract Refract Surg 2003;29:1302–6. [22] Zuckerman SJ, Aquavella JV, Park SB. Analysis of the efficacy and safety of excimer laser PTK in the treatment of corneal disease. Cornea 1996;15:9–14. [23] Oster JG, Steinert RF, Hogan RN. Reduction of hyperopia associated with manual excision of Salzmann’s nodular degeneration. J Refract Surg 2001;17:466–9. [24] Meltendorf C, Buhren J, Bug R, Ohrloff C, Kohnen T. Correlation between clinical in vivo confocal microscopic and ex vivo histopathologic findings of Salzmann nodular degeneration. Cornea 2006;25:734–8. [25] Rao A, Sridhar U, Gupta AK. Amniotic membrane transplant with superficial keratectomy in superficial corneal degenerations: efficacy in a rural population of north India. Indian J Ophthalmol 2008;56:297–302. [26] Severin M, Kirchhof B. Recurrent Salzmann’s corneal degeneration. Graefes Arch Clin Exp Ophthalmol 1990;228:101–4. [27] Sinha R, Chhabra MS, Vajpayee RB, Kashyap S, Tandon R. Recurrent Salzmann’s nodular degeneration: report of two cases and review of literature. Indian J Ophthalmol 2006;54:201–2.
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Contact Lens & Anterior Eye journal homepage: www.elsevier.com/locate/clae
Salzmann’s nodular corneal degeneration (SNCD): Clinical findings, risk factors, prognosis and the role of previous contact lens wear Samer Hamada ∗ , Kanupriya Darrad, Peter J. McDonnell Birmingham and Midland Eye Centre, City Hospital, Dudley Road, Birmingham B187QH, UK
a r t i c l e Keywords: Salzmann’s Nodular Degeneration Soft contact lens Prognosis Risk factors
i n f o
a b s t r a c t Purpose: To revisit the clinical presentations of Salzmann’s nodular corneal degeneration (SNCD) and to identify risk factors, occurrence and prognosis, and in particular to assess the role of previous contact lens wear as an aetiological factor. Methods: Retrospective case note review of all cases of Salzmann’s nodular degeneration over the last twenty years. We analysed epidemiological features, characteristics of lesions, risk factors and final outcomes. Results: Thirty eyes (19 patients) were identified with SCND. Eleven patients had bilateral disease. Our cohort included 14 female (73.7%) and 5 males (26.3%). Average age at presentation was 58.9 (range 30–75) years. Follow up range was 0–13 years. The most common presenting symptom was foreign body sensation (68.4%). Ocular pathologies were: dry eyes (56%), chronic blepharitis (32%), trichiasis (8%), trachoma (32%), previous ocular trauma (8%), and previous ocular surgery (21.4%). Sixteen percent of cases were soft monthly disposable contact lens wearers. None of our patients with rigid contact lens wear developed Salzmann’s nodules. Surgical excision was needed in 4 cases (13.3%). Two of them developed recurrent disease. Conclusion: Salzmann’s nodular corneal degeneration is a disorder affecting middle-aged white women predominantly, and seems to be associated with concomitant chronic MGD, dry ocular surface, soft contact lens wear and previous ocular surgery. The prognosis is very good, and most patients are “successfully” treated with medical management alone, and therefore correct diagnosis of the disease is paramount. If indicated, various surgical options are available and give good outcomes. However, Salzmann’s nodules can recur after penetrating keratoplasty. © 2011 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.
1. Introduction Salzmann’s nodular corneal degeneration (SNCD) is a worldwide occurring, relatively rare, non-inflammatory, slowly progressive disease originally described by Maximilian Salzmann in 1925 [1]. However, Ernst Fuchs may have made the initial case observation in 1901 [2]. SNCD is classically described as bluish-greyish nodular corneal opacities of various sizes (mostly 1–3 mm) occurring in isolation or in multiple numbers anywhere on the cornea (Fig. 1(a–b)). Salzmann’s nodules can occasionally take up fluorescein staining (Fig. 2). Histopathological findings involve thinning or denudation of the epithelium, destruction of Bowman’s layer, duplication of the epithelial basement membrane and disorganisation of collagen lamellae in the superficial anterior stroma. These histological findings are entirely non-specific and can be seen in scarring
∗ Corresponding author. Tel.: +44 (0) 7808174099. E-mail address: [email protected] (S. Hamada).
from any cause. The cause of the degeneration is uncertain and still debated upon [3], but associations with chronic ocular irritation and inflammation have been made. It may be idiopathic; however it is often associated with pre-existing corneal disease. SNCD has been associated with trachoma, interstitial keratitis, vernal keratoconjunctivitis, phlyctenular keratoconjunctivitis, ocular trauma, corneal exposure, measles, scarlet fever, and previous ocular surgery. The purpose of this study is to revisit the clinical presentations of SNCD and to identify risk factors, occurrence and prognosis. In particular, the role of previous contact lens wear in the development of SNCD will be investigated.
2. Patients and methods Retrospective case note review of all cases of Salzmann’s nodular degeneration that we have identified in our centre (Birmingham and Midland Eye Centre) over the last twenty years (March 1990–April 2010). We analysed epidemiological features, characteristics of lesions, risk factors and final outcomes.
1367-0484/$ – see front matter © 2011 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.clae.2011.02.004
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Fig. 1. (a–b) Salzmann’s nodules appear as bluish-white nodules raised above the surface of the cornea. It can be single, multiple (separated or confluent).
females (73.7%) and 5 males (26.3%). Average age at presentation was 58.9 (range 30–75) years. Follow up period varied according to initial presentation, severity, and progression of the disease; and ranged from 0 to13 years. More than half of patients were white Caucasian (11/19). The remaining were Asian (7/19) and Afro-Caribbean (1/19). Demographical data are summarised and compared with other studies in Table 1. Eleven patients had bilateral disease. Salzmann’s nodule distribution varied among patients. All eyes had peripheral corneal nodules. 10% of all eyes had lesions in the central cornea involving visual axis. We looked at the distribution of corneal lesions, which were as follows: super-nasal quadrant 28.2%, super-temporal quadrant 23%, infra-nasal quadrant 20.5%, infra-temporal quadrant 17.9%, and central cornea 10.3%. All of which were not statistically significant (Table 1). Central corneal nodules were seen in the eyes of Asian females who also showed signs of ocular surface trachoma. These females had both eyes affected with SCND but only one eye manifested Salzmann nodules in the central cornea. Peripheral corneal vascularisation (360◦ ) was seen in one patient (two eyes) who had bilateral disease and a history of bilateral penetrating keratoplasties. Penetrating keratoplasties were performed to treat severe corneal scarring from herpes simplex keratitis. The majority of patients (68.4%) complained of foreign body sensation. Other symptoms included “white spots on cornea” (5.3%) and reduced vision (5.3%). However, 15.8% were asymptomatic and referred by their optometrist to exclude the presence of treatable corneal disease (Table 1). We looked at other ocular pathologies that were documented at the time of first presentation and these included: dry eyes (56%), chronic blepharitis (32%), trichiasis (8%), trachoma (32%), previous ocular trauma (8%), previous ocular surgery (21.4%) of which 8% were post pterygium surgery (Table 1). We identified that 16% of cases were soft monthly disposable contact lens wearers but they had no other ocular pathology. None of our patients with rigid contact lens wear developed Salzmann’s nodules. Management of SNCD involved: ocular lubrication (66%), topical anti-inflammatory (33%) mainly Prednisolone 0.5% eye drops, and surgical excision in 4 cases (13.3%). Two underwent penetrating keratoplasties, one had simple surgical excision, and one had anterior lamellar keratoplasty. The disease has recurred in two patients (2 eyes), both had penetrating keratoplasty. Finally, we reported final visual outcomes i.e. visual acuities measured at last hospital visit: 21 eyes ≥ 6/9, 1 eye = 6/12, and 4 eyes ≤ 6/36 (all trachoma cases). No visual acuities data at last visit for 4 eyes.
4. Discussion
Fig. 2. Cobalt blue light shows fluorescence staining of Salzmann’s nodules.
3. Results Thirty eyes (19 patients) were identified with the clinical diagnosis of Salzmann’s nodular degeneration. Our cohort included 14
Originally Salzmann described 23 patients with bluish-white corneal lesions, 18 of whom were females [1]. Later studies by Farjo et al. and Graue-Hernandez et al. [2,3] supported Salzmann observations that SNCD affect mainly middle aged females. Our cohort reflected the same trend; 73.7% of our patients were females and the average age was 58.9 years (30–75). Furthermore, our study showed a preponderance of SNCD to affect the white population (57.9%). Graue-Hernandez reported the majority of his cases were white (76.1%) in a group where the total white population was only 47.8% [3]. However he suggested that access to medical care may have been more readily available to certain populations, which can introduce bias in the study sample. Therefore, more studies are needed to support these findings. As the majority of the patients in our study were middle aged females and older males, and the commonest associations with SNCD were dry ocular surface (56%), chronic meibomian gland dysfunction (MGD) 32%, it can be postulated that there may be an
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Table 1 Comparision of our results with those by Graue-Hernandez et al. [3] and Farjo et al. [2]. Variables
Our study
Graue-Hernandez et al. [3]
Farjo et al. [2]
Gender
Male: 26.3% Female: 73.7% 57.9 58.9 30–75 0–156 White Caucasuian: 57.9 Asian (Indian): 36.8 Afro-Caribbean: 5.2 Foreign body sensation: 68.4% Asymptomatic: 15.8% Reduction in visual acuity: 5.3% Dry eyes – 56% MGD – 32% Trachoma – 32% Contact lens wear – 16% Previous ocular surgery – 21.4% Peripheral (90%) Peripheral and central (10%) (one eye in bilateral disease) 6.6% (360◦ vascularisation) 4/30 eyes
Male: 27.8% Female: 72.2% 66.7 60.8 13–92 0–357 White Caucasian: 76.1
Male: 11.8% Female: 89.2% 63.4 54.3
Reduction in visual acuity: 30%
Reduction in visual acuity
MGD – 41.7%
MGD – 54.8% Contact lens wear – 33.3% Pterygium excision – 16%
Not stated 41/ 180 eyes
31.2% 49/152 eyes
Reduction in vision and ocular discomfort in all cases
Reduction in vision (commonest)
100% of patients with improvement in visual acuity
90.2% of patients
Reduction in vision (85.7%) Ocular discomfort (8.2%) Contact lens intolerance (6.1%) 79.2% of patients with improvement in visual acuity 100% of patients with reduced ocular discomfort
Bilateral disease (%) Mean age (years) Range of age (years) Follow up time range (months) Race (%)
Commonest symptoms at presentation
Commonest ocular co-morbidities
Location of lesions
Peripheral corneal vascularization Surgical treatment (PK or lamellar keratoplasty) Indicators for surgery
Successful surgical outcome (improvement in visual acuity)
Visual axis involvement – 30%
Recurrence of disease in 21.9% of patients Visual acuities at last visit
Lesions distribution
Not stated
4 < 6/36 (trachoma cases) 1 = 6/12 21 ≥ 6/9 4 Unknown Super-nasal quadrant 28.2% Super-temporal quadrant 23% Infra-nasal quadrant 20.5% Infra-temporal quadrant 17.9% Central cornea 10.3%
influence of changing levels of female and male sex hormones. Androgen deficiency can lead to MGD and subsequent evaporative dry eye and reduced tear production. This leads to poor epithelial protection which as mentioned earlier is thought to be a promoting factor for SNCD [4,5]. 4.1. Clinical features SNCD was bilateral in 57.9% of cases, with similar figures described by Farjo et al. [2], and Graue- Hernandez [3]. All our cases had peripheral corneal nodules, of which three involved the visual axis (peripheral nodules (90%), peripheral and central nodules (10%)). This may explain why the commonest presenting complaint in this study was of foreign body sensation (68.4%) as opposed to a decrease in visual acuity (5.3%), which was noted to be the commonest presentation in some other studies. The association of peripheral corneal vascularisation and SNCD was explored in this study, however only 2 eyes (one patient) out of 30 eyes with SNCD had peripheral vascularisation. This patient had chronic viral keratitis and a history of bilateral penetrating keratoplasties; therefore the original pathology could be responsible for the development of corneal vascularisation. Farjo [2] had demonstrated that 33.6% of eyes with SNCD had peripheral corneal vascularisation but there is no mention of whether this association was statistically significant. Recurrent corneal erosion is reported to be a possible consequence of SNCD, however this has not been observed this in any of our patients [2]. The three most common ocular pathologies associated with SNCD were dry eyes (56%), chronic blepharitis (32%), and trachoma
(32%). Blepharitis was the main ocular co-morbidity in studies by Farjo et al. and Graue-Hernandez et al. (54.8% and 41.7% respectively) [2,3]. Trachoma was the most common ocular co-morbidity in our non-Caucasian group. The trachoma sub-group which comprised patients belonging to the South Asian race only, did show a tendency to have bilateral, central corneal, and recurrent disease. All cases that needed surgery were among this group, and had poor final visual outcomes. 4.2. Formation of salzmann’s nodules There is no uniform theory to explain how Salzmann’s nodules are formed. Abbott and Forster [6] have postulated that hyaline degeneration might be a precursor of the disease. Yoon and Park [7] have further described hyaline plaques between corneal epithelium and Bowman’s layer. They suggest that histological findings are not different from a degenerative pannus or an old corneal scar following trauma or inflammation. However another possible theory suggested by Yoon and Park which requires further investigation is one of an active immune process playing a role in the pathogenesis of SNCD after detection of B and T Lymphocytes and Major Histocompatibility Complex class II antigen in histopathalogical examination of corneal specimens [7]. Furthermore, an important promoting factor for SNCD is thought to be external irritation because of poor epithelial protection. This provides the stimulus for the overgrowth of fibroblasts, eventually leading to the formation of nodules. Chronic exposure to sunlight and environmental irritants can cause hyaline changes in the nodules by precipitation of
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ground substance onto the collagen fibres [7–9]. Stone et al. have described an increase in matrix metalloproteinase-2, sub epithelial fibrosis, and disrupted Bowman’s membrane suggesting that the nodules may result from longstanding epithelial remodelling and wound repair [10]. This may support the findings in our study where the commonest associations with SNCD were blepharokeratoconjunctivitis, dry ocular surface, and a history of contact lens wear. 4.3. Contact lenses wear and SNCD We identified that 16% of cases were monthly disposable soft contact lens wearers but had no other ocular pathology. None of our patients with rigid contact lens wear developed Salzmann’s nodules. Farjo et al. [2] reported that 33.3% of SNCD cases were contact lens wearer. It is possible that the increase use of contact lenses in population has highlighted contact lens wear as a risk factor for the development of SNCD, presumably as a result of constant CL-related cornea irritation. Contact lens wear has been associated with significant corneal epithelium thinning, lower levels of oxygen uptake, as well as increase in corneal epithelial micro cysts, thinner stroma and an increase in significant levels of daytime corneal oedema [11,12]. As suggested by Yoon and Park that poor corneal epithelial protection can be a stimulus for the development of Salzmann nodules, it is important to highlight the effects of contact lens on the corneal epithelium which leads to poor epithelial protection. These factors are: (1) Stem cell turnover: contact lens wear slows down stem cell turnover and thus reducing corneal epithelial renewal [13]. (2) Corneal homeostasis: extended wear with all types of soft or rigid gas permeable lenses results in significant reduction in the rate of exfoliation of central corneal epithelium. Combined with the suppression of epithelial cell proliferation, migration, and a reduction of epithelial cell exfoliation, the corneal epithelial cell turnover is significantly slowed down in contact lens wear. These processes may be mediated by lens-induced hypoxia. Another theory is suppression of apoptosis-driven cell death seen in corneal epithelium after contact lens wear by the constant expression of Bcl-2 at the corneal surface (an antiapoptotic protein) [14]. (3) Physical presence of contact lenses which lift the lid away from the cornea leading to poor tear film stability with subsequent drying of the cornea. This is often exacerbated by incomplete blinking. A small amount of staining (at the 3- and 9-o’clock positions) is benign, but persistent epithelial erosions can lead to dellen formation, neovascularisation, Salzmann-type elevated lesions, and pseudo-pterygium formation. In fact, SNCD seen in contact lens wearer were noted in the interpalpebral fissure. This type of punctate staining is alleviated by using a larger lens, reducing edge lift with a thinner-edged lens or steeper fit, or by refitting a lens that rests under the upper lid. (4) It has been postulated that Salzmann’s nodules appear in dry eye patients who wear contact lenses. Those patients often have areas of localised drying that lead to Salzmann’s scarring [15]. Reduced corneal thickness and increased cornea surface irregularity occur after both soft and RGP contact lenses [16]. To our knowledge, SNCD has not been reported in rigid gas permeable (RGP), or scleral contact lens wearers. We propose that RGP lenses induce less ocular surface inflammation and irritation. Corneal punctate staining is seen more in soft lenses compared with rigid lenses. Soft contact lens wearer with symptoms of mild irritation or slightly decreased vision usually benefit from refitting
with a higher water content or RGP lenses. Moreover, epithelial splitting is a common finding in asymptomatic soft contact lens wearers. This finding often is overlooked on a routine examination because it usually does not cause severe symptoms and may be covered by the upper lid. The splits usually heal after the lens has been removed for 24 h, and refitting with RGP lenses prevents recurrence. Furthermore, contact lens induced superior limbal keratitis may be caused by excessive lens movement or sensitivity to thimerosal. The treatment consists of discontinuing contact lens wear until the epithelium returns to normal and the symptoms resolve. Refitting with better fitting lenses, using preservativefree solutions with a hydrogen peroxide disinfecting system, or switching to rigid gas-permeable (RGP) contact lenses may permit a resumption of contact lens wear. Ichijima at al. found out that epithelial barrier functions are more affected in soft contact lens wear compared to rigid gas permeable contact lenses wear [17]. Finally, the prevalence of neovascularisation is low with RGP or PMMA contact lenses, more common with daily wear soft contact lenses, higher with extended-wear soft contact lenses, and very high with aphakic extended-wear lenses. Extended wear of RGP lenses usually induces less central oedema than extended wear of soft hydrogel contact lenses. Confocal microscopy has helped to identify a novel type of stromal change which is chronic in nature, displaying highly reflective panstromal microdot deposits in the corneal stroma. This deposition is more common with long-term wear of contact lenses and more common with soft lenses than with RGP lenses [18]. 4.4. Management Recognition of this disorder is very important as it has a good prognosis with conservative and surgical management. Management of underlying condition is an essential part of disease control, and this was part of our protocol plan in managing patients with SCND. Symptoms related to SCND and progression of the condition may be helped by reducing or stopping contact lens wear, reviewing the fit of the contact lenses, and by providing plentiful preservative free ocular lubrication. As the condition stabilises and symptoms improve, it may be possible to cautiously resume contact lens wear but the patient should be carefully monitored for further problems or progression. In some patients superficial keratectomy can be helpful to remove very prominent and symptomatic lesions as discussed further below. The majority of our patients had nonsymptomatic inflammation accompanying scarring that show a favourable response to medical management alone. Conservative management consisted of eye lubrication, warm compresses, lid hygiene, topical steroids, and/or oral doxycycline. All patients were initially treated with ocular lubricants (preservative free). Topical steroids were needed occasionally to treat ocular surface inflammation when present. Where nodules were raised, located on the central visual axis, or particularly symptomatic, conservative treatment failed to control symptoms and therefore surgery was the next option (less than 10% of cases). The simplest method is to peel off a nodule, which is referred to as Salzmann nodulectomy (Graue-Hernández et al.). This is normally done in theatre under the microscope. Corneal epithelium is removed locally over the nodule and the nodule is then easily peeled off with forceps. Alternatively, Superficial keratectomy, lamellar or penetrating keratoplasty can be performed depending on the extent and depth of stromal involvement of the corneal nodules [19]. Excimer laser (photo therapeutic keratectomy PTK) has been used to smoothen out the surface after removal of Salzmann’s nodules [20–22]. As one would expect, PTK induced myopic shift [23,24]. In our series, four eyes needed surgical
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management. Indication for surgery was reduction in visual acuity and ocular discomfort despite being on medical treatment. One eye had simple excision of lesions, another eye underwent anterior lamellar keraroplasty, and two eyes (trachoma cases) underwent penetrating keratoplasties because of associated deep stromal opacity. Both cases had improvement in vision and relief of ocular discomfort post surgery. However, recurrence of SNCD happened in two cases that had penetrating keratoplasties. These were later treated conservatively. Previous studies have shown that the most common reason to progress towards surgical management was disturbance in vision [3,21,25]. As SNCD does not seem to consist of one clinical entity, in some cases elevated and pannus-like tissue can be manually separated from the corneal surface leaving Bowman’s layer almost untouched. In these cases subsequent photo therapeutic keratectomy (PTK) may not be necessary to smooth the surface [19]. In other cases, deep defects are left in the Bowman’s layer and in the superficial stroma after difficult mechanical removal of the nodules, which then require multiple laser ablation procedures to acquire a homogenous surface. Cauterisation of the nodules is not advisable as it may lead to corneal opacification. Penetrating or lamellar Keratoplasty may be effective in cases where the lesion extend to the mid-stroma. As patient normally has a healthy uninvolved endothelium, penetrating keratoplasty (PK) is
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generally not recommended, unless other concurrent pathologies involve the deeper stroma and endothelium. The majority of Salzmann’s nodules involve the superficial cornea; hence the preferred option is Superficial Keratectomy, especially for sub epithelial lesions within visual axis or for mid peripheral lesions inducing astigmatism [19,21,25]. 4.5. Recurrent SNCD Recurrences have been reported several years after lamellar or penetrating keratoplasty [26,27]. In our study, there were two cases of recurrent SNCD post PK where the nodules appeared on the junction of the host and donor cornea (Fig. 3(a–b)). In one case recurrent corneal nodules appeared as early as two months after the surgery. In addition to the original causes of Salzmann’s nodule formation, immune reaction in the graft can contribute to the recurrence of Salzmann’s nodules [26]. Multifactorial processes lead to corneal surface alterations, dryness, and development of epithelial defects, which may lead to scarring in Bowman’s membrane resulting in a flat opacity, eventually giving rise to characteristic nodules of Salzmann’s degeneration afterwards. Recurrence of SNCD may manifest long time after the initial surgery because the underlying aetiology may still be present despite removal of nodules and elimination of ocular surface irritation or inflammation. Long term follow up results are needed to quantify the risk of disease recurrence. Controlling post-operative ocular inflammation is a key factor to reduce the risk of recurrent disease. Yoon and Park described a case of SNCD where superficial keratectomy was performed in conjunction with amniotic membrane graft in order to prevent inflammation, scarring, and vascularisation [2]. Whereas, Bowers et al. performed superficial keratectomy with mitomycin-C (MMC 0.4 mg/ml) application and reported no recurrence of the disease in the follow up period 28 ± 15 months [21]. Therefore, superficial keratectomy seems to give a stable, successful, predictable results as well as being an economical method of preventing and treating recurrence [19]. Additional procedures can enhance results and reduce risk of disease recurrence [7,21]. 5. Conclusion Salzmann’s nodular corneal degeneration is a disorder affecting middle-aged white women predominantly, and seems to be associated with concomitant chronic MGD, dry ocular surface, soft contact lens wear and previous ocular surgery. The prognosis is very good, and most patients are “successfully” treated with medical management alone, and therefore correct diagnosis of the disease is paramount. Surgical treatment results in good outcomes (improved visual acuity and relief of ocular irritation), however recurrence is possible especially after penetrating keratoplasty. Further studies with longer follow up times are required to determine the frequency of recurrence of the disease. References
Fig. 3. (a–b) Recurrent Salzmann’s nodules on corneal graft. This patient underwent penetrating keratoplasty for SNCD. She developed recurrent nodules soon after the surgery. Initially recurrent nodules were noted at graft–host interface; however, these have later increased in number and size over time.
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