Early surgical debridement in the management of infectious scleritis after pterygium excision
© The Author(s) 2012
Received: 11 August 2011
Accepted: 31 January 2012
Published: 22 February 2012
The purpose of this study was to report outcomes of infectious scleritis after pterygium surgery, managed with antibiotic therapies and early scleral debridement.
Retrospective chart review of 13 consecutive cases of infectious scleritis after pterygium excision between 1999 and 2009 was conducted. Collected data included prior medical and surgical history, latency period between pterygium surgery and presentation of infectious scleritis, culture and histopathologic findings, antibiotic regimen, length of hospital stay, visual acuity before and after treatment, and complications.
Median follow-up was at 14 months. Twelve patients underwent prompt surgical debridement after infectious scleritis diagnosis (median, 2.5 days). Debridement was delayed in one patient. Median hospital stay was 3 days. Best-corrected visual acuity improved in ten patients, remained stable in one patient, and decreased in two patients following treatment. Complications included scleral thinning requiring scleral patch graft (1/13), glaucoma (3/13), and progression to phthisis bulbi (1/13). No patients required enucleation.
In contrast to the generally poor outcomes in the literature, early surgical debridement of pterygium-associated infectious scleritis appears to offer improved prognosis.
KeywordsInfectious scleritis Pterygium excision Surgical debridement Biofilm
Infectious scleritis is an uncommon inflammatory disease that often results in destructive complications, including loss of the affected eye . Infectious scleritis can be classified as either primary, following local infection, usually after violation of scleral integrity, or secondary, from extension or dissemination of infection from another site [2–5]. Though rare, infectious scleritis is a well-documented complication of pterygium excision that may emerge as late as two to four decades postoperatively [6, 7]. Adjunctive therapies, such as β-irradiation, mitomycin C, and excessive cauterization, have been implicated in the pathogenesis of infectious scleritis after pterygium excision.
Medical management of infectious scleritis typically results in poor prognosis . Surgical debridement, when performed, is often delayed, and these cases are frequently characterized by extended hospitalizations, deleterious complications, and dismal visual outcomes [6–9]. Prompt surgical debridement and appropriate antibiotic coverage have been associated with better outcomes. Here, we evaluated long-term outcomes in a cohort of patients with infectious scleritis after pterygium excision, managed with prompt surgical debridement and fortified antibiotics.
This is a retrospective review of 13 consecutive patients diagnosed with infectious scleritis following pterygium excision and referred to the Doheny Eye Institute Cornea Service from 1999 to 2009. All pterygium excisions were performed at outside facilities. This Institutional Review Board-approved study followed the tenets of the Declaration of Helsinki; chart review was performed in accord with the Health Insurance Portability and Accountability Act of 1996.
Diagnosis of infectious scleritis was established by four corneal specialists (SCY, JCS, JAI, RES) based on presenting signs and symptoms and, in some cases, positive bacterial culture of scleral materials. Cases with negative culture results were included if there was high clinical suspicion for infectious scleritis, e.g., history of pterygium excision, presence of purulent materials, response to antibiotics, or suggestive histopathologic findings. All of our patients were referred from outside facilities, and a majority of these patients was already on topical antibiotics
Charts were reviewed, and demographic and clinical information, including age, sex, past medical and ocular history, the ophthalmologic examination, surgical procedures, treatment strategies, and outcomes, were collected and stored in an anonymous electronic database. Results of diagnostic procedures, namely culture and antibiogram of scleral material excised during surgical debridement and histopathologic examination of biopsied tissue, were also gathered and recorded similarly. Operative records from each patient's previous pterygium surgery at other centers were unavailable, but any relevant information disclosed by the patient and documented in the chart was also collected. Common descriptive statistical methods (mean, median, standard deviation) were used for data analysis.
Technique of scleral debridement
All patients received general anesthesia, followed by preparation of the affected eye with 5% povidone–iodine solution and standard sterile technique. After placement of a wire lid speculum, the conjunctiva was approached superiorly with a peritomy, using Westcott scissors. The necrotic tissue and abscess materials were dissected under stereotactic microscopy with a Beaver 66 surgical blade and scissors, until the choroidal pigmentation was visible through the scleral fibers. No globe penetration occurred in any case. In cases that involved the sclera beneath the rectus muscle, the muscle was detached and re-anchored with interrupted 8-0 Vicryl sutures to healthy sclera after complete debulking of the underlying necrotic tissue. Occasional gentle hemostasis was achieved using bipolar cautery. After debridement, the surgical defect was left exposed, without primary closure, to ensure good exposure to the topical fortified antibiotics. In one case (patient 3), an amniotic membrane graft was used. The conjunctival edge was tucked down and anchored with interrupted 8-0 Vicryl sutures. Subconjunctival injection of vancomycin (14 mg/mL) and tobramycin (25 mg/mL) was performed. Bacitracin ointment was dispensed over the ocular surface, and the eye was protected with a light-pressure eye patch and shield for 24 h.
Clinical features of a series of patients with infectious scleritis after pterygium surgery
Age at presentation, sex
Pterygium adjunctive therapy
Latency perioda (years)
Other presenting findings
Relevant medical history
Histopathology of scleral tissue
Time between presentation and debridement (days)
Tobramycin/dexamethasone gtts, ciprofloxacin ointment, glue
Serous RD/choroidal effusion, flare
Acute/chronic necrotizing scleritisc
Acute/chronic necrotizing scleritisc
Acute/chronic necrotizing scleritisc
Choroidal effusion, posterior synechiae
Acute/chronic necrotizing inflammation, fibrotic material within blood vessels, calcified materialc
Ofloxacin gtts, moxifloxacin gtts
Acute/chronic necrotizing scleritis
Diclofenac gtts, rimexolone gtts, prednisolone gtts, homatropine gtts
Acute necrotizing scleritisc
Moxifloxacin gtts, gatifloxacin gtts, doxycyclin PO, moxifloxacin PO
Meibomian gland dysfunction
Acute necrotizing inflammation
Moxifloxacin gtts, erythromycin gtts
Serous RD, angle-closure
Acute/chronic necrotizing scleritis
Streptococcus viridans in thio broth only
Staphylococcus aureus, one colony
Tobramycin/dexamethasone gtts, homatropine gtts
Acute/chronic necrotizing scleritisc
Removal of calcium plaque over pterygium resection site, fluorometholone gtts, prednisolone, neomycin/polymyxin B/dexamethasone ointment
Prednisolone gtts, neomycin/polymyxin B/dexamethasone ointment, cyclopentolate, atropine, brimonidine
Once the patients arrived at our institution, 12 out of 13 underwent prompt surgical debridement. For the remaining patient, debridement was delayed for 32 days because of an unusual calcific plaque overlying the affected area and an initial dramatic improvement on topical fortified antibiotics alone. Excluding this outlier, the median length of time between presentation and debridement was 2.5 days (range, 0–18 days).
Cultures of scleral scrapings were positive for Pseudomonas sp. in seven cases, Eikenella corrodens in one patient (6), Streptococcus viridans in one patient (9), and Staphylococcus aureus in one patient (10). Histopathological reports were available for 11 of the 13 patients, revealing acute suppurative inflammation in ten cases and chronic inflammatory infiltrate in eight cases. Special stains for bacteria (Gram) and fungi (Gomori methenamine silver) were documented as negative in seven specimens.
Treatment outcomes after debridement and antibiotic therapy for infectious scleritis
Hospital stay (days)
BCVA before debridement
BCVA after debridement
Bleeding, scleral thinning, glaucoma, recurrence
Ciprofloxacin IV, gentamicin IV, tobramycin/dexamethasone gtts, ciprofloxacin ointment, fortified topical cefazolin and tobramycin and vancomycin and piperacillin gtts, ciprofloxacin ointment, ciprofloxacin PO
Severe scleral thinning, involvement of sclera at medial rectus
Levofloxacin IV, tobramycin/dexamethasone gtts, moxifloxacin gtts, gatifloxacin gtts
Scleral thinning, involvement of sclera at medial rectus
Fortified topical vancomycin and tobramycin gtts, gatifloxacin gtts, ciprofloxacin PO
Levofloxacin IV, fortified topical vancomycin and tobramycin gtts, gatifloxacin gtts, ciprofloxacin ointment
Scleral thinning, entropion, posterior synechiae
Cefazolin IV, fortified topical vancomycin and tobramycin gtts, ciprofloxacin gtts, moxifloxacin gtts
Severe scleral thinning requiring scleral patch graft and patch graft revision, involvement of sclera at medial rectus
Fortified topical vancomycin and tobramycin gtts, gatifloxacin gtts, gentamicin ointment, levofloxacin PO
Scleral thinning, corneal necrosis with iris adhesion, prolapsed vitreous, elevated IOP
Levofloxacin IV, Fortified topical vancomycin and tobramycin gtts, gatifloxacin gtts, moxifloxacin gtts, moxifloxacin PO, fluconazole PO, doxycyclin PO
Severe scleral thinning, glaucoma
Gentamicin IV, ciprofloxacin IV, fortified topical tobramycin and vancomycin gtts, moxifloxacin gtts, loteprednol/tobramycin gtts, ciprofloxacin ointment, ciprofloxacin PO
Scleral thinning, recurrence
Fortified topical vancomycin and tobramycin gtts, moxifloxacin gtts, gatifloxacin gtts, ofloxacin gtts, ciprofloxacin gtts
Scleral thinning, perforation, corneal haze, corneal epithelial defect that resolved
Fortified topical tobramycin and cefazolin gtts, ofloxacin gtts
Scleral thinning, choroidal detachment, involvement of sclera under medial rectus
Ciprofloxacin IV, fortified topical tobramycin and piperacillin gtts, tobramycin/dexamethasone gtts, levofloxacin gtts, ofloxacin gtts
Scleral thinning, hypertrophic conjunctival growth, choroidal detachments, serous retinal detachment
Ciprofloxacin IV, fortified topical tobramycin gtts, levofloxacin gtts
Scleral thinning, phthisis
Fortified topical tobramycin and vancomycin gtts, levofloxacin gtts, ciprofloxacin ointment, ciprofloxacin PO, erythromycin gtts
CF @ 5′
Two patients (1 and 10, Table 1) presented with history of rheumatoid arthritis and pterygium excision, which complicated the diagnostic algorithm. Nonetheless, the scleral scrape cultures were positive for bacteria in both. The presenting clinical features of patient 1 were especially complicated, including severe intraocular inflammation and choroidal and retinal double detachments. She ultimately required a second surgical debridement, 8 days after the first, with excellent visual restoration. Patient 9 also required a second debridement, 28 days after the first. Patient 8 presented with the clinical picture of endophthalmitis and angle-closure glaucoma, so surgical intervention was delayed 14 days, until the diagnosis of infectious scleritis was confirmed. Overall, the median hospital stay was 3 days (mean, 6.7 days; range, 0 to 21 days).
Preoperative best-corrected visual acuity (BCVA) ranged from 20/25 to light perception (Table 2). Postoperative BCVA ranged from 20/20 to no light perception (patient 13). Ten patients demonstrated improvement in their BCVA; one patient's BCVA remained unchanged. Two patients (9 and 13), whose preoperative visual acuities of 20/200 and counting fingers at 5 ft, respectively, decreased to hand motion and no light perception, respectively, at last visit.
We report improved outcomes of infectious scleritis after pterygium excision managed with prompt, aggressive scleral debridement and antibiotic therapy, and we contend that delayed debridement may carry worse outcomes. None of the patients in our series required enucleation; 11 of the 13 patients demonstrated stable or improved visual acuity, and the median hospital stay of our patients was 3 days. Other investigators have demonstrated higher complication rates, poorer visual outcomes, and longer hospital stays for the treatment of infectious scleritis.
A comparison of treatment outcomes of infectious scleritis reported in other studies
Number of patients
At least one debridement
Postoperative BCVA (%)
Mean hospital stay (days)
Postoperative complications (%)
Enucleations or eviscerations
Reynolds and Alfonso 
Lin et al. 
Hsiao et al. 
Complicated cataract (28)
Serous retinal detachment (22)
Choroidal detachment (17)
Choroidal and retinal detachment simultaneously (11)
Huang et al. 
Posterior synechiae (67)
Cystoid macular edema (67)
Huang et al. 
Vitreous opacity (50)
Serous retinal or choroidal detachments (25)
As previously reported, Pseudomonas sp. was the most commonly isolated organism in our series. Pseudomonas has been associated with more aggressive scleral infection and a dismal prognosis . Other organisms are tabulated in Table 1. Interestingly, Streptococcus viridans and Staphylococcus aureus were isolated from patients 9 and 10, respectively. It is unclear if these organisms represented the true infectious agents or contaminations from normal flora. E. corrodens, a gram-negative rod rarely recovered in soft tissue infections, was isolated from patient 6 .
Even though no microorganisms were observed on histopathologic evaluation of the scleral specimens, most revealed acute, necrotizing (suppurative) inflammation, and many had a mixed acute–chronic infiltrate consistent with bacterial infections scleritis . A possible explanation would be administration of topical antibiotics by the referring physicians and implementation of aggressive antibiotic regimen prior to surgical debridement at our institution.
During debridement, the surgeons noted small pockets of abscess within the necrotic sclera and beneath areas of seemingly healthy sclera, consistent with two previous reports [6, 12]. All of the patients in this series had a history of pterygium excision. The latency period between pterygium resection and scleral infection in our series, 4 months to 20 years, is comparable to the literature . Application of adjunctive therapies such as mitomycin C and b-radiation at the time of pterygium has been implicated in the pathogenesis of scleral infection through destruction of the protective blood supply to the conjunctiva and outer sclera. Diabetes mellitus, another possible risk factor predisposing patients to infectious scleritis , was present in five (38%) of our cases.
Biofilm formation may also be implicated in the refractory nature of infectious scleritis to medical management alone. In the human body, bacteria exist predominantly in two states: planktonic and sessile . Planktonic forms are highly susceptible to antibiotics and host defenses, whereas sessile forms are more resistant. The sessile form is seen mainly as a biofilm on the surfaces of implanted devices or biologic tissues. Within the biofilm architecture, bacterial colonies are encased in an extracellular matrix of exopolysaccharides, which provide protection from hostile environments. The inner, sessile, oxygen-deprived microcolonies have limited mobility, a slow growth rate, a different synthetic rate, and a reduced susceptibility to antibiotics . For some antibiotics, the concentration required to penetrate the biofilm can be thousands of times the concentration required for planktonic bacteria of the same strain [14, 16, 17]. The biofilms may evolve into a physically diverse structure containing channels and interstitial voids, as previously reported . Thus, physiological heterogeneity within a bacterial colony and pharmacokinetic limitations are possible explanations for the frequent failure of antibiotic treatment alone in the management of infectious scleritis [18–20]. Accordingly, early surgical debridement may be important in disrupting the barriers to antibiotic efficacy. This was our rationale for a lower threshold for surgical debridement in this study.
After debridement, we decided against the use of cryopreserved human amniotic membrane graft on the exposed, debrided area in all but one patient (3). Maximum exposure is desirable for topical antibiotic penetration and prevention of incubation of any microbes remaining at the surgical site. Hydration of the bare and thinned sclera with continual medical therapy has been suggested as an effective modality to facilitate re-epithelialization of the sclera after bare sclera excision of pterygium . Second, we wanted to avoid obscuring visualization of early recurrence or the formation of abscesses [6, 22]. Adequate re-epithelialization of the exposed sclera was observed in 12 eyes shortly after debridement. For patient 3, however, a human amniotic membrane graft was deemed appropriate because re-epithelialization did not appear likely to occur due to the severity of scleral thinning .
As previously discussed, none of the patients with involvement of the sclera under the medial rectus complained of diplopia following surgery, possibly indicating that they were able to achieve fusion or that there was suppression of the misaligned eye. Management of diplopia would involve prism or strabismus surgery. However, surgical management may not be a feasible option given the poor structural integrity of the debrided eye (Fig. 1).
Thus, prompt and aggressive surgical debridement may contribute to better outcomes in infectious scleritis after pterygium excision. We postulate that the generally poor outcomes reported in the literature may be related to the limited penetration of antibiotics into bacterial microabscesses and biofilms in the nearly avascular, infected sclera and to the delay in surgical intervention aimed at disrupting these defenses and debulking the microbial load. Prospective, comparative studies may not be possible because this disease entity has low incidence and high risks of permanent vision impairment or loss of globe. As other studies reported high rates of conversion to surgical debridement [4, 6–8], we advocate vigilant monitoring and prompt debridement if indicated.
Conflict of interest
The authors declare that they have no conflict of interest.
Research to Prevent Blindness, NEI Core Grant EY03040, and Baxter Foundation Junior Faculty Award to Dr. Samuel C. Yiu.
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