Polyhexamethylene biguanide (0.02%) alone is not adequate for treating chronic Acanthameoba keratitis

Effectiveness and Safety of Topical Chlorhexidine and Vitamin E TPGS in the Treatment of Acanthamoeba Keratitis: A Survey on 29 Cases

This study aimed to test the effectiveness of a solution of chlorhexidine (CHX) and D-α-tocopheryl polyethylene glycol succinate (Vitamin E TPGS or TPGS) in the treatment of Acanthamoeba keratitis (AK) via a prospective, interventional case series study. Twenty-nine consecutive patients with AK were enrolled. At baseline, best-corrected visual acuity (BCVA), slit lamp examination, confocal microscopy, and polymerase chain reaction (PCR) were performed. Topical therapy with CHX 0.02% and VE-TPGS 0.2% was administered hourly/24 h for the first day, hourly in the daytime for the next three days, and finally, every two hours in the daytime up to one month. BCVA and ocular inflammation were recorded after two weeks, four weeks, and three months from baseline. Mean logMAR BCVA significantly improved at two weeks (0.78) compared to baseline (1.76), remaining stable over time (0.80 at four weeks, 0.77 at three months). Ocular inflammation improved in 14 eyes at 2 weeks, with further slow improvements in all cases. At three months, no patient had signs of corneal inflammation. The presence of corneal scars was first recorded at the two-week follow-up, with an enlargement at the four-week follow-up. At the three-month follow-up, 19 eyes still showed corneal opacities. In conclusion, the tested solution was shown to be effective for the treatment of AK. Furthermore, it might represent a good first-line treatment.

Chlorhexidine Monotherapy with Adjunctive Topical Corticosteroids for Acanthamoeba Keratitis

PURPOSE

To assess the efficacy of chlorhexidine monotherapy for Acanthamoeba keratitis, and to determine the therapeutic outcomes of concomitant topical corticosteroids.

METHODS

In this prospective interventional case series, 31 eyes of 31 patients with Acanthamoeba keratitis (AK) were treated with chlorhexidine 0.02% as monotherapy, from April 2010 to April 2011. The diagnosis of AK was made based on clinical manifestations and positive confocal microscopic (confoscan 3.4, Nidek Co. Ltd., Gamagori, Japan) results. We report the percentage of a favorable clinical response within two weeks of initiating treatment, worsening of the infection while receiving chlorhexidine, recovery of visual acuity (VA), duration of treatment with chlorhexidine and corticosteroids, necessity for addition of other anti-Acanthamoeba agents, presence of corneal scar at the end of the treatment, and need for penetrating keratoplasty (PK).

RESULTS

Two weeks after initiation of chlorhexidine, improvement in signs and symptoms was observed in 26 (83.9%) patients but 3 eyes required the addition of propamidine. After initial improvement in one patient, the infection worsened, necessitating the addition of Polyhexamethylene Biguanide (PHMB) and propamidine. A total of 26 (83.9%) patients received topical corticosteroids with mean duration of 65.8 ± 45.1 days. In 22 (71%) eyes, final visual acuity was ≥0.80. Improved VA occurred in 29 eyes (93.5%). Optical PK was considered in 3 (9.7%) eyes and a corneal scar developed in 8 (25.8%) eyes.

CONCLUSION

Chlorhexidine is effective for monotherapy in AK and could be a good choice for initiating treatment. After the initial response to anti-Acanthamoeba agents, corticosteroids can be used as adjunctive therapy depending on the clinical condition.

Practice patterns and opinions in the treatment of acanthamoeba keratitis

PURPOSE

Management of acanthamoeba keratitis remains challenging for ophthalmologists. We conducted a survey of members of The Cornea Society to elicit expert opinions on the diagnosis and treatment of acanthamoeba keratitis.

METHODS

An online survey was sent to all subscribers of The Cornea Society via the kera-net listserv. Descriptive statistics were performed.

RESULTS

Eighty-two participants completed the online survey. Of the 82 respondents, 76.8% included the combination of clinical examination and culture in their diagnostic strategy and 43.9% used confocal microscopy. Most respondents (97.6%) had used combination therapy with multiple agents to treat acanthamoeba keratitis at some point in the past, whereas a smaller proportion (47.6%) had ever used monotherapy. Respondents most commonly chose polyhexamethylene biguanide as the ideal choice for monotherapy (51.4%), and dual therapy with a biguanide and diamidine as the ideal choice for combination therapy (37.5%). The majority of respondents (62.2%) reported using topical corticosteroids at least some of the time for acanthamoeba keratitis. Keratoplasty was an option considered by most respondents (75.6%), although most (85.5%) would only perform surgery after medical treatment failure.

CONCLUSIONS

There was a wide range of current practice patterns for the diagnosis and treatment of acanthamoeba keratitis. The lack of sufficiently powered comparative effectiveness studies and clinical trials makes evidence-based decision-making for this disease difficult.

Comparison of polyhexamethylene biguanide and chlorhexidine as monotherapy agents in the treatment of Acanthamoeba keratitis

PURPOSE

To compare the therapeutic outcomes of polyhexamethylene biguanide (PHMB) and chlorhexidine for Acanthamoeba keratitis.

DESIGN

Prospective, double-masked, randomized comparative study.

METHODS

Fifty-six eyes of 55 patients with Acanthamoeba keratitis were randomized to receiving PHMB 0.02% or chlorhexidine 0.02%. Diagnosis was made based on positive culture results (cornea or contact lens case) or on clinical grounds. The primary outcome measure was treatment failure defined as failure to induce a favorable clinical response within two weeks. Secondary outcomes were: 1) recovery of visual acuity (VA), 2) the degree of corneal scarring posttreatment, or 3) the need for penetrating keratoplasty.

RESULTS

Fifty-one eyes completed the study. Twenty-three eyes received PHMB and 28 received chlorhexidine. Ninety-eight percent were contact lens wearers. Eighteen (78%) PHMB patients were treatment successes compared with 24 (85.7%) chlorhexidine patients (P = .71). Diagnosis was confirmed by positive corneal culture results in 26 cases (51%). Diagnosis was made within 28 days in 29 cases (56.9%), between one and two months in 13 cases (25.5%), and after more than two months in eight cases (15.7%). Improvement in VA was seen in 13 eyes (56.5%) receiving PHMB vs 20 eyes (71.4%) receiving chlorhexidine. Mild one-quadrant corneal scarring was seen in 43.5% of eyes receiving PHMB and 71.4% of eyes receiving chlorhexidine, whereas moderate corneal scarring in two or three quadrants was seen in 21.7% of eyes receiving PHMB and in 10.7% of eyes receiving chlorhexidine. Five eyes worsened while receiving PHMB vs four eyes worsening while receiving chlorhexidine. Penetrating keratoplasty was required in three eyes from PHMB group and in two eyes from chlorhexidine group.

CONCLUSIONS

Outcomes were similar when using PHMB and chlorhexidine as monotherapy agents in treating Acanthamoeba keratitis.