Groove and peel technique DALK for refractory Acanthamoeba keratitis

Acanthamoeba keratitis (AK) is a rare but serious eye infection caused by Acanthamoeba, a free-living amoeba commonly found in soil, freshwater, and tap water. Although it predominantly affects contact lens wearers, it can also occur following exposure to contaminated water or corneal trauma.[1] The amoeba’s active trophozoite form is susceptible to some medications, whereas the resistant cystic form poses a significant therapeutic challenge. First-line treatments typically involve diamidines and biguanides, which exhibit cysticidal activity and achieve success rates ranging from 35% to 86%.[2,3] For refractory cases, options include corneal cryotherapy, amniotic membrane transplants, PK, and DALK.[3] A 23-year-old female contact lens wearer presented with severe pain, redness, and reduced vision in her left eye persisting for 1 month. The visual acuity in the affected eye was limited to counting fingers at 2 feet. Slit-lamp examination and anterior segment OCT showed corneal infiltrates involving the visual axis and extending to the mid-stroma [Fig. 1a and b]. Corneal scraping, examined with Gram’s and Giemsa stains, confirmed the presence of Acanthamoeba cysts [Fig. 2a and b]. Treatment was initiated with hourly polyhexamethylene biguanide (PHMB) 0.02% and chlorhexidine 0.02% eye drops, along with moxifloxacin 0.5% eye drops four times a day, homatropine 2% eye drops four times a day, and CMC 0.5% eye drops four times a day. Despite the regimen, the condition worsened over the subsequent 2 months, with the corneal infiltrate progressing toward the limbus [Fig. 3a and b]. Considering a delayed response to medical management, a therapeutic DALK procedure was performed under local anesthesia. An 8.5 mm host trephine was used, positioned slightly off-center to encompass the abscess. An initial attempt at the big-bubble technique failed; therefore, Descemet’s membrane (DM) baring was achieved using the Groove and Peel method (GP-DALK) method. A 9 mm donor trephine was employed, and the graft was secured with 16 interrupted 10-0 nylon sutures [Fig. 4a-h]. Anti-AK therapy was continued postoperatively for 6 months. One month post surgery, loteprednol etabonate 1% was started at four times a day. At the 7-month follow-up, the graft remained clear and compact [Fig. 5a and b], with BCVA improving to 20/40 in the left eye. The patient was advised to continue loteprednol 1% once daily until the next follow-up in 3 months.Figure 1: (a and b) S/L examination and anterior segment OCT showing corneal infiltrates involving the visual axis and extending up to mid-stroma levelFigure 2: (a and b) Grams and Gimesa stain showing the presence of acanthamoeba cystFigure 3: (a and b) The corneal infiltrate showing progression despite medical therapyFigure 4: (a-h) Technique of GP-DALK after an attempted failed BBFigure 5: (a and b) AS-OCT and clinical photo showing clear and compact graft at the last follow-upDiscussion DALK has been described for AK cases refractory to medical management. Sarnicola et al. recommend early DALK for cases poorly responsive to medical therapy.[4] The GP-DALK technique is straightforward to learn and a reproducible technique. Studies have shown that GP-DALK consistently enables removal of most of the corneal stroma, potentially reaching the pre-Descemet’s layer.[5] Our case highlights that GP-DALK can be successfully used in refractory cases of AK as an alternative to layer-by-layer or big bubble DALK. Authors' contributions Prateek Gujar: Conception of idea, collection of data, writing the manuscript. 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.