MICROBIAL KERATITIS FOLLOWING EPI-OFF CORNEAL COLLAGEN CROSSLINKING PROCEDURE Dr. K V Satyamurthy Dr. Jaysheel V N Cornea-Refractive Surgery Dept MM Joshi Eye Institute Hubli Authors have no financial or proprietary interest in any material or methods

Introduction  Keratoconus is a degenerative, noninflammatory ectasia of the cornea characterized by progressive corneal thinning and irregular astigmatism.  Corneal collagen crosslinking (CXL) with riboflavin and ultraviolet-A light (UVA) technique has been used to increase the corneal rigidity of keratoconic eyes and prevent further progression of keratoconus.  We report a case of microbial keratitis which developed following collagen crosslinking with riboflavin and UVA for the treatment of keratoconus

20 year old female was referred to the Cornea Department of MM Joshi eye institute in March 2013 for treatment of Progressive keratoconus. She was intolerant for contact lens wear. OD OS BSCVA 6/18, N8 6/9, N6 Manifest Refraction -4DS -1DS 130º Anterior segment Severe keratoconus Mild keratoconus IOP (mmHg) Pachymetry 414µ 495µ Kf 28º 167º Ks 118º 77º

 The patient was scheduled for CXL with riboflavin–UVA light in the right eye. The risk and potential complications of the surgery were fully explained to the patient.  Standard surgical procedure with sterile techniques with topical anesthesia was performed.  Epithelium was removed by 20% alcohol-assisted method in the central 8mm area followed by instillation of hypotonic riboflavin 0.1% (K-link) solution eye drop once every 3 minutes for 30 minutes.  This was followed by UV irradiation for 25 minutes to the central 8mm of cornea. Riboflavin 0.1% solution eye drops were instilled once every 5 minutes for 25 minutes.  Bandage contact lens was used for dressing the cornea.

Patient was started on gatifloxacin 0.5% ophthalmic solution 6 times a day, homatropine eye drops 2 times a day and Carboxymethylcellulose sodium eye drops 6 times a day. At the first follow-up visit, 2 days after surgery, patient complained of pain, redness, photophobia and decreased vision in operated eye

White nodular infiltrates Hypopyon Stromal infiltrates Ciliary congestion Immediate management started with scraping the corneal stromal infiltrates with 15No. BP blade and sending the samples for Gram stain; Blood agar and thioglycolate broth for bacterial culture. Smears revealed no micro-organisms Satellite lesions

 Hourly fortified Vancomycin (50mg/ml), fortified Amikacin (20mg/ml) were started on the same day along with atropine sulphate eye drops twice daily.  Cultures were subsequently (after 48hours of incubation) positive for Staphylococcal epidermidis  On 4 th Post-operative day ocular inflammation and corneal infiltrates had regressed.

 Topical antibiotic agents were reduced to 4 times a day for 2 more weeks.  Topical flourometholone 0.10% (FML) 3 times a day was added to the antibiotic regimen.  15days after CXL, an eye examination revealed moderate leucomas surrounded by stromal haze in the upper and lower central cornea.  Topical flourometholone was continued twice a day for 1 additional month. POST 15DAYS

1 MONTH after treatment, the UCVA in the right eye was 6/60 and BSCVA was 6/18, manifest refraction -4.50DS 30º Slit-lamp evaluation shows a central leucomatous opacity and the central corneal thickness was 381µm POST 30DAYS

Discussion  Conventional C3R requires epithelial removal for surgery and epithelial defect takes 2-4 days to heal completely.  Compromised epithelium predisposes to bacterial keratitis, hence epi-on C3R may lower the risk of same.  Coagulase-negative staphylococci, including S epidermidis, are usually present in normal ocular flora.  These microorganisms are very common etiologic agents of bacterial keratitis and usually cause opportunistic infection when the epithelium is compromised.  Use of bandage soft contact lens could be a risk factor since it can harbour micro-organisms.

 Corneal scraping to obtain enough material for detailed microbiological evaluation is very much emphasized in order to detect and expedite the treatment.  This case report emphasizes the importance of conducting collagen crosslinking procedure under sterile precautions.  Informed consent should include occurrence of microbial keratitis and the related outcomes  Postoperative counselling to report any early signs of microbial keratitis is a must. Conclusion