Non-contact lens related Acanthamoeba keratitis

Abstract

The purpose of the study is to describe epidemiology, clinical features, diagnosis, and treatment of Acanthamoeba keratitis (AK) with special focus on the disease in nonusers of contact lenses (CLs). This study was a perspective based on authors’ experience and review of published literature. AK accounts for 2% of microbiology-proven cases of keratitis. Trauma and exposure to contaminated water are the main predisposing factors for the disease. Association with CLs is seen only in small fraction of cases. Contrary to classical description experience in India suggests that out of proportion pain, ring infiltrate, and radial keratoneuritis are seen in less than a third of cases. Majority of cases present with diffuse infiltrate, mimicking herpes simplex or fungal keratitis. The diagnosis can be confirmed by microscopic examination of corneal scraping material and culture on nonnutrient agar with an overlay of Escherichia coli. Confocal microscopy can help diagnosis in patients with deep infiltrate; however, experience with technique and interpretation of images influences its true value. Primary treatment of the infection is biguanides with or without diamidines. Most patients respond to medical treatment. Corticosteroids play an important role in the management and can be used when indicated after due consideration to established protocols. Surgery is rarely needed in patients where definitive management is initiated within 3 weeks of onset of symptoms. Lamellar keratoplasty has been shown to have good outcome in cases needing surgery. Since the clinical features of AK in nonusers of CL are different, it will be important for ophthalmologists to be aware of the scenario wherein to suspect this infection. Medical treatment is successful if the disease is diagnosed early and management is initiated soon.

Acanthamoeba keratitis - Camouflage entity in Nepal

“…All of them were from agricultural background and four patients had history of trauma with vegetative matter. Similar ndings of higher association of acanthamoeba keratitis among agricultural worker with history of trauma due to vegetative matter have been reported from other developing countries [4,6,19,20,21].…”

Acanthamoeba Ocular Infection: Anomalous Presentation of a Potentially Vision-Threatening Condition

“…Nevertheless, atypical presentation may be the rule and, in developing countries, exposure to contaminated soil or water, and a history of ocular trauma are the main predisposing factors, whereas CL wearing has lower importance [12,13]. In a recent published series, a typical presentation with disproportionate pain, ring infiltrates, and radial keratoneuritis was observed in less than a third of cases [3]. Cases of painless AK with normal vision have also been reported [14][15][16].…”

“…Soft CL are known to be at increased risk than rigid gas permeable (RGP) lenses [2]. AK may have a proteiform presentation [3,4]. At the onset, signs and symptoms are often aspecific and the clinical picture may be mistaken as a fungal, bacterial or viral infection leading to a delay in the diagnosis.…”

Pearls and paradigms in Infective Keratitis

“…▪ Giemsa stain - It helps identify inclusion bodies in viral and chlamydia infections. It can also help differentiate bacteria and fungi, identify cysts and trophozoites of Acanthamoeba [ 20 ].…”

“…Potential risk factors for Acanthamoeba keratitis are damage to the corneal epithelium, contact lenses, contaminated water, or solution and host susceptibility [ 20 ]. Clinical features of Acanthamoeba keratitis are severe ocular pain, epithelial irregularity and dendriform pattern, severe anterior and posterior scleritis, ring shaped stromal infiltrate, anterior uveitis, persistent or recurrent epithelial erosion, radial keratoneuritis, disciform keratitis [ 20 ]. Culturing the specimen on a confluent lawn of the E. coli plated on non-nutrient agar is the microbiological diagnostic technique.…”