Early therapeutic lamellar keratoplasty for acanthamoeba keratitis followed by implantable Collamer lens for visual rehabilitation.

We are reporting the case of a 25-year-old female who developed acanthamoeba keratitis after wearing contact lenses for high myopia. She was diagnosed as acanthamoeba and started the treatment of antiacanthamoeba for 3 consecutive weeks, followed by bare Descemet's therapeutic lamellar keratoplasty (LKP) with the maintenance of antiacanthamoeba treatment to control the infection. In the late postoperative period, visual rehabilitation was obtained by insertion of implantable Collamer lens (ICL) with her final visual outcome was 20/30. For acanthamoeba keratitis, early bare Descemet's therapeutic LKP has a better outcome in comparison to late penetrating keratoplasty in terms of infection eradication and globe preservation. After removal of all sutures, the refractive error can be corrected with photorefractive procedures as well as ICL. Copyright:

Introduction

Acanthamoeba is an amoebic parasite which targets immunocompromised patients causing central nervous system and skin infections.[12] However, it may involve the cornea in relatively healthy individuals.[2] One of the most known risk factors for acanthamoeba keratitis in western countries is wearing contact lenses (CL), while developing countries usually presents as a result of trauma or water exposure.[13]

The clinical suspension of acanthamoeba keratitis is the most important step in the diagnosis which leads to early detection and better outcome.[145] Symptoms may involve corneal pain and photophobia, while clinical signs may show a radial pattern of perineural infiltrates and ring infiltrates.[1]

Acanthamoeba keratitis usually leads to deep stromal involvement which makes the penetration of medication and eradication of the diseased area less.

Managing patients with acanthamoeba keratitis remains difficult due to the challenging diagnosis and the absence of high efficacy medications.[4] The medical treatment of acanthamoeba keratitis may last for several months, while performing penetrating keratoplasty (PK) for cases that failed medical therapy is relatively poor and usually done as a result of recurrent infections and late diagnosis.[46]

It is controversial to perform corneal transplant in the acute infection period.[4] However, some reports showed successful outcomes for performing lamellar keratoplasty (LKP) in nonpenetrating fungal keratitis which has more advantages compared to the conventional PK.[47]

We describe a case of acanthamoeba keratitis unresponsive to medical treatment that was managed successfully with deep anterior LKP using lamellar dissection in the form of bare Descemet's, followed by implantable Collamer lens (ICL) insertion to correct refractive error after removal of all sutures and final corneal stability.

Case Report

A 25-year-old female who is known to wear CL for her high myopia was presented to King Khaled Eye Specialist Hospital in the emergency room with severe pain, photophobia, and decreased vision in the left eye for 1-week duration. On reviewing her past history, there were no significant previous episodes. Her visual acuity was 20/20 OD with CL and hand motion OS. On slit-lamp examination, the right eye was within normal limits and the left eye showed normal lids, severe conjunctival injection with chemosis, and central large corneal epithelial defect with stromal infiltrate. The anterior chamber was deep with + 2 cells [Figure 1]. The fundus examination was within normal limits in both eyes.

Figure 1

Left corneal slit lamp with deep central corneal infiltrate

The patient was admitted with the diagnosis of microbial keratitis and started on empirical fortified antibiotics (cefazoline and ceftazidime eye drops every 1 h, 50 mg/ml both).

Two days from admission, all symptoms and the coronal infiltrate got worse. The cornea started to form a ring shape infiltrate. The suspicion of acanthamoeba became high and the patient was started on chlorhexidine and Brolene eye drops every 1 h and fluconazole tablet 200 mg PO once daily.

Three weeks later, the signs were improving and the decision was to do bare Descemet's LKP under general anesthesia using an 8.25 mm donor graft tissue and 8.00 mm host cut. A vacuum trephine was used to cut through the recipient cornea with 3 mm free zone for a partial thickness then a bare Descemet's dissection with 66 blade was created (one shot per Descemet). A total of 16 bites of 10.0 nylon interrupted sutures were placed and buried. Subconjunctival injection of cefuroxime was administered at the conclusion of surgery.

In the postoperative period, the patient was kept on chlorhexidine and Brolene eye drops every 2 h around the clock and the fortified cefazoline and ceftazidime were decreased to every 4 h around the clock [Figure 2].

Figure 2

Left eye, 2 weeks postlamellar keratoplasty without infiltrate with intact all sutures

In the early postoperative days, the corneal epithelial defect healed in 1 week and the graft was clear. There was no sign of recurrence of infection. The histopathological report confirmed the diagnosis of acanthamoeba keratitis based on the presence of acanthamoeba cysts which were staining with PAS and GMS stains.

On June 30, 2013, fortified antibiotics were replaced with vigamox eye drop every 6 h and antiacanthamoeba medications in the form of chlorhexidine, Brolene eye drops, and oral fluconazole were maintained with the same frequency and Pred Forte eye drops every 8 h.

On July 7, 2013, the patient was discharged home on the same medications. She was followed up closely in the outpatient clinic and the eye was quiet without signs of recurrence.

The patient was stable over the postoperative period. She was deeply interested to have refractive surgery in her right noninfected eye as she prefers to avoid the risk of CL and cannot tolerate glasses because of the anisometropia which was done successfully.

On follow-up, all sutures were removed. The antiacanthamoeba were maintained and tapered over 6 months. Examination revealed VA OD was 20/20 without correction since she had PRK. While VA OS was 20/400 improving with pinhole to 20/200. The left eye examination showed clear graft with no suture or signs of recurrence, the anterior chamber was deep and quiet, and the lens was clear. Her refraction OS was −11.0–9.00 × 125 reaching 20/25 vision [Figure 3].

Figure 3

Left eye 8 months postlamellar keratoplasty. (a) The left eye shows clear graft after removal of all sutures. (b) Left eye corneal slit lamp shows a clear graft

The plan was to correct the refractive error of the left eye with ICL, which was done on August 17, 2014 since the patient has high significant refractive error.

The patient was seen 2 weeks post ICL, she was doing fine, and her VA OS was 20/40 and with pinhole 20/30. On her last follow-up on December 2019, her visual acuity was 20/30 without correction, and the patient was very satisfied with the outcome.

Discussion

PK in late stages after substantial peripheral extension of keratitis has high failure rates. While doing it in earlier stages has better outcomes.[4] Although a reported case series showed good outcome of PK in relatively late stages with quiet eyes, apart from having cataract and glaucoma in some of these cases which necessitate cataract extraction and glaucoma surgeries.[8]

The early intervention with keratoplasty is helpful in minimizing the risk of corneal perforation, endothelial damage, and eradication of the amoeba.[4]

A previous report of treating two patients with acanthamoeba keratitis with lamellar keratectomy and amniotic membrane transplantation was published with good outcome.[5]

Parthasarathy and Tan also describe the treatment of acanthamoeba keratitis with deep LKP in their patient which was almost consistent with our approach in terms of early intervention and management.[4] However, our case was different in being a deep lamellar with bare Descemet membrane, followed by ICL insertion 6 months after the removal of all sutures with extremely good visual outcome.

Perforation during LKP is a high possibility. Therefore, all patients should sign a consent for possible conversion to PK.

Postsurgical rehabilitation of vision after removal of all sutures is important to restore vision.

Furthermore, maintenance of antiacanthamoeba treatment should be maintained for a longer period of time to ensure the eradication of the pathogen and prevent complications.[5]

In conclusion, acanthamoeba keratitis is usually treated medically while surgical intervention used to be late. As a result, the chance of complications is high in the form of vascularization cataract and glaucoma as well as severe scarring. Early surgical intervention is very helpful to eradicate the pathogens, minimize complications, and rehabilitate the vision. Long postoperative medications are mandatory, and the refractive error can be treated using ICL. Our patient was managed with this approach and we could restore the globe's integrity and vision.

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.