News Update on Keratitis : July – 2020

Mycotic keratitis: epidemiology, diagnosis and management

Mycotic keratitis (an infection of the cornea) is an important ocular infection, especially in young male outdoor workers. There are two frequent presentations: keratitis due to filamentous fungi (Fusarium, Aspergillus, phaeohyphomycetes and Scedosporium apiospermum are frequent causes) and keratitis due to yeast-like fungi (Candida albicans and other Candida species). In the former, trauma is usually the sole predisposing factor, although previous use of corticosteroids and contact lens wear are gaining importance as risk factors; in the latter, there is usually some systemic or local (ocular) defect. The clinical presentation and clinical features may suggest a diagnosis of mycotic keratitis; increasingly, in vivo (non-invasive) imaging techniques (confocal microscopy and anterior segment optical coherence tomography) are also being used for diagnosis. [1]

Classification of herpes simplex virus keratitis.

PURPOSE:We propose a nomenclature for classification of herpes simplex virus (HSV) keratitis. We hope that a more consistent classification system will lead to a better understanding of the disease processes, thus resulting in improved diagnosis, treatment, and patient outcomes. METHODS:A review of the literature was performed to evaluate current HSV classification systems. These systems were evaluated in the context of both current clinical and basic science studies and our own clinical observations. RESULTS:The proposed classification system is based on the anatomy and pathophysiology of the specific presentations of HSV keratitis. Anatomically, the primary level of corneal involvement, whether epithelium, stroma, or endothelium, must be elucidated. Pathophysiologically, the cause of the inflammation. whether immunologic, infectious, or neurotrophic, must be determined. There are four major categories of HSV keratitis. [2]

Latanoprost and herpes simplex keratitis

PURPOSE: To report three cases in which herpes simplex keratitis developed after initiation of latanoprost therapy.

METHODS: Case report.

RESULTS: One patient with a history of herpes simplex keratitis had recurrence of herpes simplex keratitis with latanoprost treatment, resolution when latanoprost was stopped, and another recurrence when rechallenged with latanoprost. A second patient with a history of herpes simplex keratitis had bilateral recurrence with initiation of latanoprost; antiviral therapy could not eradicate herpes simplex keratitis until the latanoprost was discontinued. The third patient with latanoprost-associated herpes simplex keratitis cleared with the discontinuation of latanoprost and start of antiviral therapy; reinstitution of latanoprost with prophylactic antiviral medication kept the cornea clear, but as soon as the antiviral suppression was discontinued, herpes simplex keratitis reappeared. [3]

Presentation and Outcome of Microbial Keratitis in Ilorin, Nigeria

Aim: To determine the presentation and outcome of microbial keratitis among patients at University of Ilorin Teaching Hospital (UITH) in Ilorin, Nigeria.

Methods: A 12-month, prospective, hospital-based longitudinal study was conducted by examining all patients with clinical features of infective keratitis, who met the inclusion criteria. A post-treatment evaluation was done at 6 weeks in all cases, during which visual acuity and any complications were re-assessed. The outcome measures included interval between onset and presentation, extent of corneal involvement and final visual acuity. The data was analysed with the SPSS version 20.0 software.

Results: Fifty-five eyes of 54 patients were studied. There were 32 males (59.3%) and 22 females (40.7%). The mean age was 36.9 years (± 12.1). The predisposing factors were trauma in 30 (55.6%) cases, self-medication with topical steroids in 12 (22.2%) and the use of traditional eye medication in 12 (22.2%). All of the participants presented with pain, tearing, photophobia and reduction in vision. The right eye was involved in 37 patients (67.2%). The presenting visual acuity in the affected eyes was 6/60 or less in 31 (56.4%), 6/60–6/24 in 18 (32.7%) and 6/6–6/18 in 6 eyes (10.9%). At 6-week follow-up, 5 eyes (9.1%) had <6/60 visual acuity, 40 (72.7%) had 6/60–6/24 and 10 (18.2%) had 6/6–6/18.The risk factors for poor outcome were a centrally located lesion (p=0.018), an area of corneal involvement greater than 4mm (p=0.007) and a lesion affecting the deeper layers of the cornea (p=0.002). [4]

Risk Factors for the Development of Inpatient Exposure Keratitis

Purpose: To identify the risk factors for inpatient exposure keratitis and make possible the development of improved educational tools for providers.

Methods: Retrospective chart review of inpatient ophthalmology consults at a major New York City teaching hospital, identifying patients with exposure keratitis. Patients included were seen by the ophthalmology consult service over a 3 year period and had exposure keratitis severe enough to require active treatment.

Results: The four most common risk factors were sedation and mechanical ventilation (22/61, 36%), facial nerve palsy (10/61, 16%), nocturnal lagophthalmos (7/61,11%) and cicatricial or post-surgical lid changes (5/61,8%).Inpatient location was identifiable in 59 cases. 31% (18/59) of cases came from the physical therapy and rehabilitation floors and 24% (14/59) from the intensive care units. There were significantly more exposure keratitis cases identified during the 1st Half of the Academic Year, July through December, (45/61,74%) than the 2nd Half of the Academic year, January through June. (16/61, 26%) [P=0.03]. [5]

Reference

[1] Thomas, P.A. and Kaliamurthy, J., 2013. Mycotic keratitis: epidemiology, diagnosis and management. Clinical Microbiology and Infection, 19(3), pp.210-220.

[2] Holland, E.J. and Schwartz, G.S., 1999. Classification of herpes simplex virus keratitis. Cornea, 18(2), pp.144-154.

[3] Wand, M., Gilbert, C.M. and Liesegang, T.J., 1999. Latanoprost and herpes simplex keratitis. American journal of ophthalmology, 127(5), pp.602-604.

[4] Saka, S.E., Ademola-Popola, D.S., Mahmoud, A.O. and Fadeyi, A., 2015. Presentation and outcome of microbial keratitis in Ilorin, Nigeria. Journal of Advances in Medicine and Medical Research, pp.795-803.

[5] Lehpamer, B., Lyu, T., Fernandez, K., Futterman, H.A. and Asbell, P., 2014. Risk factors for the development of inpatient exposure keratitis. Ophthalmology Research: An International Journal, pp.344-351.