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 Table of Contents  
CASE REPORT
Year : 2021  |  Volume : 33  |  Issue : 1  |  Page : 75-77

An unusual case of scleral thinning with uveal exposure following pterygium surgery and its management


Department of Ophthalmology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India

Date of Submission16-Apr-2020
Date of Acceptance19-May-2020
Date of Web Publication19-Apr-2021

Correspondence Address:
Dr. Pratima Chavhan
Department of Ophthalmology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry - 605 006
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/kjo.kjo_45_20

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  Abstract 


To report unusual cases of acute onset, complete, non-infected, localized scleral thinning with uveal exposure post pterygium excision and how to manage a case. A 32-year-old female presented with complaints of mild irritation of both eyes for 3 months. On examination, she was found to be having nasal pterygium encroaching 2 mm over the cornea. She underwent an uneventful right eye pterygium excision with conjunctival autograft and was given topical antibiotics and steroid eyedrops. On follow up after 2 weeks she was found to have full-thickness scleral thinning at the site of pterygium excision with uveal exposure. Scleral patch graft with amniotic membrane transplantation was done. Scleral thinning and uveal exposure following an uncomplicated pterygium surgery without mitomycin is a rare serious complication.

Keywords: Cornea, mitomycin, pterygium, scleral thinning, scleritis


How to cite this article:
Chavhan P, Stephen M, Babu K R, Pragathi S. An unusual case of scleral thinning with uveal exposure following pterygium surgery and its management. Kerala J Ophthalmol 2021;33:75-7

How to cite this URL:
Chavhan P, Stephen M, Babu K R, Pragathi S. An unusual case of scleral thinning with uveal exposure following pterygium surgery and its management. Kerala J Ophthalmol [serial online] 2021 [cited 2021 Jul 25];33:75-7. Available from: http://www.kjophthal.com/text.asp?2021/33/1/75/314096




  Introduction Top


Pterygium is an abnormal fibrovascular proliferation of the subconjunctival tissue, which encroaches from conjunctiva onto the cornea with symptoms such as irritation and dry eye. Commonly employed surgical techniques for the treatment of pterygium include excision with conjunctival autograft, use of mitomycin C (MMC), and amniotic membrane transplantation (AMT). A 32-year-old female presented with complaints of irritation of both eyes (BE) for 3 months. She had nasal pterygium and underwent an uneventful right eye (RE) pterygium excision with conjunctival autograft. On 2 weeks of follow-up, she presented with localized scleral thinning with uveal exposure. Donor scleral patch graft with AMT was done, which showed complete epithelialization during 3 months of follow-up.

Scleral thinning is a rare complication that can occur commonly with the use of antiproliferative agent MMC[1],[2] and the use of beta-irradiation[3] or if sclera is damaged inadvertently during surgery by deep dissection or excessive cauterization.


  Case Report Top


A 32-year old female presented with complaints of mild irritation of BE for 3 months. On examination, she had visual acuity of 20 / 30 with nasal pterygium in BE. Corneal topography showed astigmatism of 1.57D at 114 degrees in the RE. Schirmer's test I and II were > 15mm. The patient underwent RE nasal pterygium excision with conjunctival autograft. MMC, suture, or glue was not used. On 1-week follow-up, conjunctival graft was in situ. Two weeks later, the patient came for routine follow-up with no complaints, and on examination of RE, she had a localized full-thickness scleral thinning with uveal exposure. On slit-lamp examination, scleral thinning was 4 mm × 3 mm in size with well-defined margins and the surrounding sclera was not epithelialized. There was no active sclera inflammation surrounding the melt. The lateral border was 3 mm away from the limbus with minimal chemosis [Figure 1]a and [Figure 1]b. Dilated fundus evaluation was normal. B scan ultrasonography did not reveal any signs of posterior scleritis. Intraocular pressure by Goldmann applanation tonometry was 12 mmHg. The other eye examination was normal. The patient was referred to rheumatologist for the evaluation of immunosuppression. Systemic steroids were not given as she was asymptomatic without any signs of inflammation and full-thickness scleral melt at the presentation. Bacterial and fungal cultures were sent to rule out infection.
Figure 1: (a and b) Slit-lamp images of patient showing markedly thinned sclera with underlying uveal exposure and mild conjunctival congestion

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RE donor scleral patch graft was done under subtenon's anesthesia. Intraoperatively, it was striking to note that medial rectus muscle was exactly inserting at the medial border of the scleral melt [Figure 2]a. A square-shaped scleral patch graft was sutured with 10-0 ethilon [Figure 2]b and the amniotic membrane was secured over the scleral graft using fibrin glue [Figure 2]c and [Figure 2]d.
Figure 2: Intraoperative images of patient (a) insertion of medial rectus at medial border of thinning, (b) after placing donor scleral patch graft at the site of perforation. (c and d) Amniotic membrane transplantation over scleral graft

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The patient was started on topical steroid and antibiotic eye drops with lubricants on the first postoperative day. She underwent complete immunological workup and found to be negative for antinuclear antibody, antineutrophil cytoplasmic antibody, and rheumatoid factor. Montoux was negative. Her hemoglobin was 12.2 g%. The erythrocytes sedimentation rate was 63. Thyroid-stimulating hormone (TSH) was 16.54 and antithyroid peroxidase antibodies (anti-TPO) were >1300; both were elevated suggesting autoimmune thyroiditis but the patient was clinically asymptomatic. The patient had hypothyroidism and was on thyroxine supplementation.

The patient was serially followed up with steroid and antibiotic eye drops. She gradually improved with good graft apposition [Figure 3]a. At 3 months follow-up, it showed complete epithelialization [Figure 3]b.
Figure 3: (a) 1 month postoperative image of the patient with graft in place. (b) 3 months postoperative image showing complete epithelialization

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  Discussion Top


Scleral thinning can occur in various systemic and local conditions such as autoimmune diseases, chronic scleritis, myopic degenerations, local scleral pathologies, scleral injuries, prolonged irradiation, transscleral laser cycloablation, strabismus surgery, deep sclerectomy, overuse of antimetabolites, and excessive use of cautery. Scleral thinning postpterygium surgery is usually associated with the use of MMC, excessive cautery, and bare sclera technique.[4]

To the best of our knowledge, this is an unusual case to be reported of sudden onset postpterygium excision scleral thinning with uveal exposure in an uncomplicated pterygium excision without using mitomycin and without any infection in a clinically normal patient with autoimmune thyroiditis, which to our understanding is a very rare complication. In our case, the patient was very young and her thyroid parameters were elevated such as TSH and anti-TPO, but her other systemic autoimmune workup was negative and no clinical evidence of connective tissue diseases. It was a full-thickness sterile scleral melt with a uveal show, which necessitates immediate surgical interventions to avoid perforation, secondary infection, and rarely endophthalmitis.

The overall incidence of scleral necrosis after pterygium excision has been reported to be 0.2%–4.5%.[5],[6] A higher rate of scleral melt Has been linked to bare sclera technique with adjunctive use of MMC or beta irradiation. Ti SE Reported 6 of the 20 cases were quite scleral melt without evidence of autoimmune diseases, but in all of the cases, MMC or beta irradiation was used as an adjunctive agent.[7] Gokhale and Samant reported one case of surgically induced necrotizing scleritis with bare sclera technique in a patient with serological evidence of connective tissue disease.[8]

Few infective etiologies have been implicated in the causation of scleral necrosis and aggravation of sclerokeratitis following pterygium excision.[9] And, the risk is high in patients with autoimmune disease and with the use of mitomycin during pterygium surgery. The use of split-thickness dermal graft also reported in the literature for a corneoscleral defect.[10]

In our patient, surgical trauma or the use of antiproliferative agents were not responsible for the scleral melt. Excessive cauterization might be the cause for scleral thinning which was not noticed intraoperatively. As the patient presented with full-thickness melt, the progression of the thinning was not monitored to rule of surgically induced necrotizing scleritis by giving systemic steroids. Infective scleritis cannot be considered as a differential diagnosis in this case as infective workup was negative. The presence of autoimmune thyroiditis suggests that the patient could be susceptible to immune-mediated reactions. Even the patient is asymptomatic clinically, autoimmune diseases have to be ruled out before taking the patient for any ocular surgery to prevent complications. AMT following scleral patch graft is the best option in such a condition as it helps in epithelialization and healing. Early diagnosis and immediate surgical interventions are successful in managing such complications.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Rubenfeld RS, Pfister RS, Stein RM, Foster CS, Martin NF, Stoleru S, et al. Ocular complications of topical mitomycin-C after pterygium surgery. Ophthalmology 1992;99:1647-54.  Back to cited text no. 1
    
2.
Au Eong KG, Tseng PS, Lim AS. Scleral necrosis and infection 15 years following pterygium excision. Singapore Med J 1995;36:232-4.  Back to cited text no. 2
    
3.
MacKenzie FD, Hirst LW, Kynaston B, Bain C. Recurrence rate and complications after beta irradiation for pterygia. Ophthalmology 1991;98:1776-80.  Back to cited text no. 3
    
4.
Yamazoe K, Shimazaki-Den S, Otaka I, Hotta K, Shimazaki J. Surgically induced necrotizing scleritis after primary pterygium surgery with conjunctival autograft. Clin Ophthalmol 2011;5:1609-11.  Back to cited text no. 4
    
5.
Tarr KH, Constable IJ. Late complications of pterygium treatment. Br J Ophthalmol 1980;64:496-505.  Back to cited text no. 5
    
6.
Sullivan LJ, Snibson G, Joseph C, Taylor HR. Scedosporium prolificans sclerokeratitis. Aust N Z J Ophthalmol 1994;22:207-9.  Back to cited text no. 6
    
7.
Ti SE, Tan DT. Tectonic corneal lamellar grafting for severe scleral melting after pterygium surgery. Ophthalmology 2003;110:1126-36.  Back to cited text no. 7
    
8.
Gokhale NS, Samant R. Surgically induced necrotizing scleritis after pterygium surgery. Indian J Ophthalmol 2007;55:144-6.  Back to cited text no. 8
[PUBMED]  [Full text]  
9.
Singh RP, McCluskey P. Scedosporium prolificans sclerokeratitis 10 years after pterygium excision with adjunctive mitomycin C. Clin Exp Ophthalmol 2005;33:433-4.  Back to cited text no. 9
    
10.
Mauriello JA Jr., Pokorny K. Use of split-thickness dermal grafts to repair corneal and scleral defects – A study of 10 patients. Br J Ophthalmol 1993;77:327-31.  Back to cited text no. 10
    


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  [Figure 1], [Figure 2], [Figure 3]



 

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