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 Table of Contents  
Year : 2021  |  Volume : 1  |  Issue : 4  |  Page : 648-650

Collagen cross-linking with riboflavin-induced aggravation of polymicrobial keratitis

1 Senior Resident, Advanced Eye Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India
2 Cornea Consultant, Cornea Centre, Chandigarh, India
3 Department of Ophthalmology, University of Maryland, USA

Date of Submission17-Feb-2021
Date of Acceptance24-May-2021
Date of Web Publication09-Oct-2021

Correspondence Address:
Dr. Ashok Sharma
Cornea Centre, 2463-2464 Sector 22C, Chandigarh - 160 022
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijo.IJO_409_21

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A 21-years-old female presented with pain, redness, watering, and diminished vision in right eye (OD). Slit lamp biomicroscopy revealed infective keratitis and microbiological tests revealed mixed infection of bacteria and fungus. The patient was treated with a combination of topical (antibacterial and antifungal) medication and oral itraconazole. The patient showed no response. Tab voriconazole was added. Observing no response after another week, collagen cross-linking was performed. On day two, sudden worsening of corneal infiltrates involving total cornea was observed. Topical colistin 0.19% drops were added. The patient did not respond to treatment and a therapeutic graft was performed. The postoperative period was uneventful and no recurrence was observed.

Keywords: Collagen crosslinking, PACK-CXL, polymicrobial keratitis, riboflavin, UV radiation

How to cite this article:
Kulshrestha A, Sharma R, Sharma A, Nirankari VS. Collagen cross-linking with riboflavin-induced aggravation of polymicrobial keratitis. Indian J Ophthalmol Case Rep 2021;1:648-50

How to cite this URL:
Kulshrestha A, Sharma R, Sharma A, Nirankari VS. Collagen cross-linking with riboflavin-induced aggravation of polymicrobial keratitis. Indian J Ophthalmol Case Rep [serial online] 2021 [cited 2021 Oct 28];1:648-50. Available from: https://www.ijoreports.in/text.asp?2021/1/4/648/327744

Infectious keratitis is a vision-threatening condition that occurs due to bacterial, fungal, protozoal, or viral infection.[1] The major risk factors include corneal epithelial trauma, preexisting ocular surface disease, dry eyes, contact lens wear, chronic topical steroids exposure, and immunosuppression.[2] Antimicrobial agents are the mainstay of the treatment; however, due to antimicrobial resistance/poor response to antibacterial, antifungal, and antiprotozoal drugs, a continuous search of alternative adjunct options is on.

Goodrich used riboflavin, a photosensitizer, and ultraviolet (UV) light to inactivate microorganisms in the plasma, platelets, and red cell products.[3] Riboflavin when exposed to UV light generates free oxygen radicals, causing photo oxidative damage to genetic material and death of pathogens.[3] Several studies have shown corneal cross-linking (CXL) effective in managing infectious keratitis except for viral keratitis.[4] There is no report on rapid worsening of infection following CXL.

Herein, we report a case of sudden worsening of mixed bacterial and fungal keratitis following CXL leading to corneal melting and subsequently requiring emergency keratoplasty.

  Case Report Top

A 21-year-old female presented with pain, redness, watering, and diminished vision in OD for the last 2 weeks. There was no history of a foreign body falling into the eye or similar episode in the past. The patient had been diagnosed as a case of viral keratoconjunctivitis elsewhere. She had been treated with the topical antibiotic and steroid by the referring ophthalmologist. On noticing worsening, the patient was referred to us for further treatment.

At presentation, her visual acuity was 5/60 in OD and 6/6 in OS. Intraocular pressure was 16 mmHg in the left eye. Slit lamp biomicroscopy revealed a dry-looking creamy white infiltrate measuring 7.0 mm × 5.0 mm. There was intervening clear stroma surrounding the dense infiltrate [Figure 1]a. Examination of the left eye did not reveal any abnormality. Direct microscopy of the smears revealed Gram-positive cocci and septate hyphae, while culture grew Aspergillus flavus. The patient was started on combination therapy of topical moxifloxacin hydrochloride 0.5% (Alcon Laboratories, Inc, Fort Worth, TX, USA) 2 hourly, natamycin 5% suspension (Sun Pharmaceutical Industries Ltd) 2 hourly, atropine sulphate 1% (Entod Pharmaceutical Ltd) thrice, and tab itraconazole 200 mg twice daily.
Figure 1: (a) At presentation, 7.0 × 5.0 mm infiltrate with intervening clear stroma. (b) After 1 week of treatment, infiltrate size same but more dense. (c) At 2 weeks pre PACK-CXL, increase in the density of infiltrate, endothelial plaque with overlying stromal edema and hypopyon (1.5 mm). (d) Postoperative day 1, decrease in infiltrate and disappearance of hypopyon. (e) On postoperative day 2, sudden increase in infiltrate suddenly involving almost total cornea. (f) Clear graft 4 weeks after therapeutic penetrating keratoplasty

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After 1 week of medical therapy, the size of infiltrate was the same (7.0 mm × 5.0 mm) but the density had increased [Figure 1]b. Repeat corneal scraping again revealed septate hyphae. Tab itraconazole was discontinued and tab voriconazole added. The topical medication was continued as before. At 2 weeks of treatment, the patient showed a further increase in the density of infiltrate [Figure 1]c. Endothelial plaque with overlying stromal edema and hypopyon measuring 1.5 mm had appeared. Since there was no response to medical treatment, options of intrastromal injection of voriconazole or photoactivated chromophore for keratitis-corneal collagen cross linking (PACK-CXL) were discussed. The patient was reluctant to get intrastromal injection and gave her consent for PACK-CXL.

PACK-CXL was performed according to Dresden protocol (UVA 3 mw/cm2 × 30 min). Slit lamp examination on postoperative day 1 revealed a decrease in size of infiltrate and disappearance of hypopyon [Figure 1]d. Topical antibacterial and antifungal treatment was continued as before. On postoperative day 2, the infiltrates suddenly increased and involved almost total cornea, 1.0 to 1.5 mm short of limbus [Figure 1]e. Frequent instillations of topical colistin 0.19% were initiated along with existing medications. The patient did not show any improvement 48 hours after adding topical colistin 0.19%. The patient had increase in the central corneal melt and was advised penetrating keratoplasty. She underwent therapeutic penetrating keratoplasty on day 6, after PACK-CXL. The cultures from the excised corneal button did not grow any microorganism. Histopathology of the corneal button also did not reveal any bacterial or fungal pathogen. Medical treatment was continued, graft remained clear, and no recurrence of infection was observed in 6 weeks.

  Discussion Top

CXL is currently one of the most widely used treatments for arresting the progression of keratoconus. PACK-CXL using Dresden protocol (3 mW/cm2 CXL for 30 min) is favored to treat infective keratitis. A meta-analysis on PACK-CXL reported successful healing in 88% of bacterial keratitis and 78% of fungal keratitis patients.[4] PACK-CXL aids in healing of corneal ulcer by inactivation of pathogens and by increasing the resistance of cornea collagen to enzymatic degradation.[5] Indications for PACK-CXL were worsening despite anti-microbial treatment (74%), resistance to antibiotics (68%), and corneal thinning (53%).[6] In our patient, PACK-CXL was performed for worsening of infection, despite intensive antimicrobial treatment.

PACK-CXL in deep keratomycosis and Acanthamoeba keratitis has been reported to be ineffective. PACK-CXL in moderate fungal keratitis has been reported of no advantage over medical treatment.[7] Our patient had polymicrobial keratits, combined bacterial and fungal keratitis. To the best of our knowledge, sudden worsening of infective kerartitis and corneal melt following PACK-CXL has not been reported.

It is difficult to speculate on the possible reason of sudden worsening of infective keratitis in our patient. It is possible that topical steroid exposed polymicrobial keratitis may respond differently to PACK-CXL than nonsteroid exposed corneas. CXL has been documented to reduce the permeability of antimicrobial drugs across corneal epithelium in animal studies.[8] A clinical study has also reported a reduced ocular penetration of topical medications after CXL.[9] Thus, reduced concentration of antimicrobial agents in the stroma and the anterior chamber could be the possible reason for sudden worsening. Our patient had been treated for viral keratoconjunctivitis by the referring ophthalmologist. It is possible that our patient had the primary viral corneal disease and got super added polymicrobial keratitis. Reactivation of herpes simplex virus (HSV) following CXL has been reported by various authors.[10] Aggravation of keratitis in our case may be due to reactivation of HSV.

Corneal melting in infective keratitis is a serious condition that can cause corneal perforation and loss of vision. Treatment options for corneal melt include topical and systemic immunosuppression, oral doxycycline, oral vitamin C, cyanoacrylate tissue adhesive, and emergency keratoplasty, depending on the underlying disease and the stage of corneal melt. A recent study provided evidence that CXL in addition to the destruction of microorganisms in infective keratitis stops collagen degradation occurring as a part of corneal inflammatory response.[11] In another study, PACK-CXL has been advocated as an effective additional option in the management of infectious keratitis with corneal melting.[12] In this study, compared to 3 corneal perforations in the control group, none occurred in the CXL group.[12] CXL increases the biomechanical strength of corneal collagen fibres and has been advocated an effective option to maintain corneal integrity in impending corneal perforations.[13] CXL in established corneal perforation stiffens the corneal tissue and facilitates the execution of emergency procedures.[13] However, in our patient, PACK-CXL was not effective.

  Conclusion Top

The authors aim to caution ophthalmologists that PACK-CXL although has been reported effective in treating infective keratitis, rarely it may cause sudden worsening of the condition necessitating emergency penetrating keratoplasty.

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


Conflicts of interest

There are no conflicts of interest.

  References Top

Saeed A, D'Arcy F, Stack J, Collum LM, Power W, Beatty S. Risk factors, microbiological findings, and clinical outcomes in cases of microbial keratitis admitted to a tertiary referral center inireland. Cornea 2009;28:285-92.  Back to cited text no. 1
Green M, Apel A, Stapleton F. Risk factors and causative organisms in microbial keratitis. Cornea 2008;27:22-7.  Back to cited text no. 2
Goodrich RP. The use of riboflavin for the inactivation of pathogens in blood products. Vox Sang 2000;78(Suppl 2):211-5.  Back to cited text no. 3
Papaioannou L, Miligkos M, Papathanassiou M. Corneal collagen cross-linking for infectious keratitis: A systematic review and meta-analysis. Cornea 2016;35:62-71.  Back to cited text no. 4
Panda A, Krishna SN, Kumar S. Photo-activated riboflavin therapy of refractory corneal ulcers. Cornea 2012;31:1210-13.  Back to cited text no. 5
Hsia YC, Moe CA, Lietman TM, Keenan JD, Rose-Nussbaumer J. Expert practice patterns and opinions on corneal cross-linking for infectious keratitis. BMJ Open Ophthalmol 2018;3:e000112.  Back to cited text no. 6
Vajpayee RB, Shafi SN, Maharana PK, Sharma N, Jhanji V. Evaluation of corneal collagen cross-linking as an additional therapy in mycotic keratitis. Clin Experiment Ophthalmol 2015;43:103-7.  Back to cited text no. 7
Tschopp M, Stary J, Frueh BE, Thormann W, De Smet J, Van Bocxlaer J, et al. Impact of corneal cross-linking on drug penetration in an ex vivo porcine eye model. Cornea 2012;31:222-6.  Back to cited text no. 8
Tappeiner C, Tschopp M, Schuerch K, Frueh BE. Impact of corneal cross-linking on topical drug penetration in humans. Acta Ophthalmol 2015;93:e324-7.  Back to cited text no. 9
Kymionis GD, Portaliou DM, Bouzoukis DI, Suh LH, Pallikaris AI, Markomanolakis M, et al. Herpetic keratitis with iritis after corneal crosslinking with riboflavin and ultraviolet A for keratoconus. J Cataract Refract Surg 2007;33:1982-4.  Back to cited text no. 10
Schnitzler E, Spörl E, Seiler T. Bestrahlung der Hornhaut mit UV-Licht und Riboflavingabe als neuer Behandlungsversuch bei einschmelzenden Hornhautprozessen, erste Ergebnisse bei vier Patienten [Irradiation of cornea with ultraviolet light and riboflavin administration as a new treatment for erosive corneal processes, preliminary results in four patients]. Klin Monbl Augenheilkd 2000;217:190-3.  Back to cited text no. 11
Müller L, Thiel MA, Kipfer-Kauer AI, Kaufmann C. Corneal cross-linking as supplementary treatment option in melting keratitis: A case series. Klin Monbl Augenheilkd 2012;229:411-5.  Back to cited text no. 12
Said DG, Elalfy MS, Gatzioufas Z, El-Zakzouk ES, Hassan MA, Saif MY, et al. Collagen cross-linking with photoactivated riboflavin (PACK-CXL) for the treatment of advanced infectious keratitis with corneal melting. Ophthalmology 2014;121:1377-82.  Back to cited text no. 13


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