The most established risk factor for Acanthamoeba keratitis is contact lens use. It is also associated with the use of contaminated home-made saline solution for storage and cleaning of contact lens [7
]. The contaminated solution becomes a medium for the growth of microorganisms
such as bacteria and yeast, which provides an ideal environment for the development of Acanthamoeba
. The amoebae attach to the contact lens and can infect the corneal stroma through a small corneal abrasion [7
This patient admitted to reusing his daily “disposable” contact lenses. Acanthamoeba keratitis has been described previously [4
] in patients using such contact lenses. He claimed that he used saline for storage overnight and denied the use of tap water. He admits to wearing contact lenses whilst in the shower and bath. There was no history of eye trauma
, exposure to contaminated soil or use of contact lens whilst engaging in water sport activities and hot tub use.
Poor hygiene practices and the inappropriate handling of contact lens increase the potential risk of dissemination from other areas of colonization. Acanthamoeba
has been isolated from nasal swabs of healthy individuals [1
]. The HIV status of this patient could have also contributed to the infection. Acanthamoeba
is a known opportunistic organism in HIV-infected patients.10 There is also evidence that HIV positive individuals are more prone to paranasal sinus disease and lesions in the ear, nose and throat [8
]. It is therefore possible to extrapolate that dissemination from the nasal sinus and passages might have played a role in the initial corneal infection
It is worth noting that there was no history of opportunistic infection in our patient. It appears that HIV infection may be coincidental rather than influential on causation or clinical features. Nevertheless, there was a notable absence of severe pain in our patient, often described as out of proportion to clinical findings, despite normal corneal sensation and the absence of peri-neural infiltrates, pathognomonic for acanthamoebal infection [3
]. A lack of typical symptoms in Acanthamoeba keratitis
have been described in previous case reports as well.
The lack of severe pain in our patient could be attributed to a high pain threshold. His HIV status could have also altered his pain perception. Pain sensation arises from inflamed tissue driven by the immune system
. Due to the pathophysiology of an HIV infection, compromised leucocyte function can subdue the process of inflammation. This may have contributed to the lack of pain in the patient’s infected eye.
Our patient had very poor vision
in his left eye due to a spontaneous detachment/ reattachment of the retina (count fingers). Three months after presentation, his acuities were HM right eye and count fingers left eye. He was 43 years old, self-employed and desperate for some form of visual improvement. The idea of performing a full thickness PK in an inflamed eye was not entertained, as the chances of graft failure would be too high [3
]. The patient was to remain on treatment with Chlorhexidine, PHMB and Brolene for at least six months [3
We obtained a retinal opinion from our professorial department with regard to improving the vision in the non-affected left eye. This was deemed to be not possible. It was decided that best way of achieving a short term visual improvement and establishing some control over the infection was to perform a lamellar graft. This took place 3 months after the patient’s initial presentation.
The patient was pleased with the visual outcome from the lamellar graft (6/60) and remained on Chlorhexidine, PHMB and Brolene for the next six months. Topical steroids (Prednisolone 0.5% minims) were used throughout.
After six months on this treatment the lamellar graft opacified, but a quiet eye was achieved. The hosts’ final PK specimen was reported as free of trophozoites and cysts. The patient then underwent a full thickness PK with a subsequent improvement in acuity to 6/24.
The limiting factors in terms of improving visual acuity were pupil mydriasis and the development of cataract
, presumably from drop toxicity.
Eight months after the full thickness PK the graft remained quiet and so phaco- emulsification cataract surgery with intraocular lens implantation was performed, targeting low myopia
. The patient’s final best-corrected visual acuity was 6/9 and he was pleased with the final visual result. He maintains his self-employment status.