Fungal Keratitis following the Application of Green Tea Bag Warm Compresses Open Access

Local warm ocular compresses are the first-line of treatment for meibomian gland dysfunction (MGD) [1]. The heating mechanisms can be divided into two main categories: designated devices and homemade preparations [2]. Homemade options, often explicitly suggested by medical providers, may include hard-boiled eggs, hot towels, cotton balls embedded with heated water and warm tea bags [3].

Fungal keratitis is a leading cause of ocular morbidity worldwide, particularly in tropical and subtropical countries, carrying a relatively poor prognosis compared to other forms of infectious keratitis [4]. This results from various causes, such as delayed microbiological identification, suboptimal efficacy, and penetration of antifungal agents, the potential morphologic pleomorphism in cultures making proper identification difficult, and a broad spectrum of drug resistance to existing medications [5, 6].

This case report presents the development of severe fungal keratitis caused by an ostensibly innocuous source. The CARE Checklist has been completed by the authors for this case report, attached as online supplementary material (for all online suppl. material, see https://doi.org/10.1159/000546055).

A 29-year-old healthy patient presented to the emergency room of our ophthalmology department on February 22, 2021, complaining of pain, redness, tearing, and decreased vision in his left eye. Three weeks prior to presentation, patient had swollen lids and was instructed by his family doctor to use warm compresses in addition to local mupirocin ointment. One week later, a tea bag ruptured over his left eye, leading to a red and painful eye within a couple of days with progressive worsening of symptoms.

The findings at the initial examination were corrected distance visual acuity (glasses) 0.0 LogMAR in the right eye and 0.7 LogMAR in the left eye, improving to 0.5 LogMAR with a pinhole. Intraocular pressure was 14 mm Hg, Goldman tonometry. The slit lamp examination was unremarkable in the right eye except for mild MGD. The left eye was hyperemic with swollen lids and MGD. The left cornea had five foci of whitish infiltrates with overlying epithelial erosions inferiorly and paracentrally, with localized inferior edema (Fig. 1a). There was no anterior chamber reaction. The lens was clear, and the retina was normal. The patient was admitted for thorough diagnosis and treatment. Upon admission, cultures were taken, and the patient received moxifloxacin drops hourly. Fungi do not always grow in cultures and direct microscopy is a clear evidence that the infection was caused by fungal infection. The fact that also bacteria or other microbials did not grow is also an indicative that was caused by fungi and not bacteria [7‒9]. Cultures showed no fungal growth. Moxifloxacin drops were decreased to four times a day, and hourly voriconazole 1% drops were initiated. Three days later, the patient underwent intrastromal peri-infiltrates injections of voriconazole 50 μg/0.1 mL which were repeated 1 week later.

A swept-source anterior segment optical coherence tomography system (CASIA 2, Tomey Corporation, Nagoya, Japan) from this period exhibits the depth of the fungal infiltration (Fig. 2a, b). The infiltrates significantly improved, and the patient was discharged on March 14, 2021, with topical voriconazole 1% 6 times a day and moxifloxacin drops three times a day in his left eye until follow-up.

Several follow-up examinations showed progressive improvement. However, 3 months of post-discharge, the patient reported worsening of symptoms and returned with a diffuse scar and a ring-shaped opacity. Cultures showed no growth, and no microorganisms were identified on microscopy. Voriconazole 1% 6 times a day was continued, and the patient showed improvement in the following days (Fig. 1b).

Nine months of post-presentation, the corrected distance visual acuity was 0.0 LogMAR in the right eye and 0.7 LogMAR in the left eye (Pinhole 0.3 LogMAR). The eye was completely quiet, with no infiltrates or corneal staining. There was significant corneal scarring, thinning, and fine corneal neovascularization. The patient was instructed to continue with voriconazole drops 6 times a day and was started on loteprednol etabonate 3 times a day. Two months later, both loteprednol etabonate and voriconazole were stopped. Rehabilitation with a contact lens was offered, but the patient refused. Corneal transplantation was discussed as a potential long-term solution but was deferred due to the patient’s stable ocular status and reluctance to undergo further surgical intervention. The patient was stable at the final follow-up in January 2022 (Fig. 1c).

This case presentation depicts a 29-year-old healthy patient who developed fungal keratitis after utilizing a green tea bag as a vehicle for warm compresses. MGD is defined as a disease of the meibomian glands, commonly characterized by terminal duct obstruction and or qualitative and or quantitative changes in the glandular secretion, which may result in alteration of the tear film, ocular surface inflammation, and symptoms of eye irritation [10].

Warm compresses are a first-line treatment for MGD, prevalent in 70–90% of patients with dry eye disease [11, 12]. In MGD, dirt, bacteria or mite excretions, and meibum produced by the glands can remain in the glands for extended periods. This can result from individual or a combination of causes, such as incomplete blinking or biofilm buildup at the glands openings [10]. The meibum consistency in these glands is denser, more of a gel or paste, rather than the liquid form found in healthy glands, and therefore, has a higher melting temperature. One of the goals when attempting to rehabilitate the tear film is to excise the poor-quality material and allow a more consistent healthy flow from the glands. Heating the eyelids helps soften and partially melt any lipidic remaining material obstructing the glands. With maintained hygiene and proper pressure from consistent, complete blinking on the glands, meibum quality improves and inflammation recedes, contributing to tear film quality and stabilization [10].

Tea and tea products are produced by processing tea plants’ buds, leaves and stems using various procedures [13]. It is classified based on the processing technique and fermentation degree into globally accepted categories (General Administration of Quality Supervision, 2014); unfermented (green tea), slightly fermented (white tea and yellow tea), semi-fermented (oolong tea), fully fermented (black tea), and post-fermented tea (dark tea) [13]. Although teas are rich in bioactive substances that can inhibit some microorganisms, fungi and mycotoxins (which are secondary metabolites of toxigenic fungi and can cause latent, chronic and acute toxic effects on animals and humans), they may still occur during manufacturing steps or from associated environments (cultivation, processing, packaging, storage, and transport) [13]. Unfermented, slightly fermented and semi-fermented teas have fewer processing steps, therefore, are easier to keep toxigenic fungi and mycotoxins out of contamination, yet they can be affected. Fermented (black tea) and post-fermented (dark tea) teas generally undergo more processing and have higher water activity, so they are more prone to contamination with toxigenic fungi and mycotoxins [13]. Previous studies showed that baking, frying, extrusion, and microwaving could reduce mycotoxins in food ingredients to various levels. However, most mycotoxins are stable at temperatures below 120°C [13].

Green tea has gained particular attention among the tea varieties due to its significant health benefits, namely, antioxidant, anti-inflammation, anticancer, anti-cardiovascular, antimicrobial, antihyperglycemic, and anti-obesity properties [14]. One can only surmise that the availability, the ease of acquiring retained heat, and the above mentioned possible benefits may encourage using this particular method for ocular warm compresses. Although the cornea is constantly exposed to the external environment and comes into contact with irritants and potential pathogens, this generally does not lead to infection due to the ocular surface complex defense system, including tear film enzymes and proteins [15].

Loteprednol etabonate was introduced at a late stage of treatment. The use of corticosteroids in fungal keratitis remains controversial. In this case, the corticosteroid was introduced only after prolonged antifungal treatment and clinical stabilization, in order to manage persistent corneal inflammation and prevent excessive scarring. The potential benefits of reducing inflammation and minimizing long-term visual impairment were carefully weighed against the risks and treatment was prescribed with close monitoring to confirm there was no fungal resurgence.

In contrast to systemic fungal infections, which typically affect immunocompromised hosts, fungal keratitis can develop in both the immunocompromised and immunocompetent. Significant morbidity is associated with fungal keratitis, with most patients left with moderate visual impairment and approximately 25% requiring surgical interventions, often unsuccessful [15]. We believe the development of fungal keratitis in this healthy patient was directly associated with the rupture of the tea bag used as warm compress. It is appropriate to note that there are many commercially available warm compress options, many include single-use or washable covers, or antiseptic materials.

While the limitation of this case is the lack of direct culture or microscopic evidence of fungus growth, our patient had significant improvement with topical voriconazole 1% drops and 50 μg/0.1 mL intrastromal injections. However, final visual acuity was low and there was corneal scaring. To the best of our knowledge, this is the first report associating fungal keratitis to tea bags.

This report presents a rare case of fungal keratitis caused by a tea bag rupture used as a therapeutic device and, to our knowledge, the first reported. While this low-cost prevalent treatment is generally beneficial, one must ensure that the application tool to implement warm compresses does not become a source of infection.

Ethical approval is not required for this study in accordance with local or national guidelines. Written informed consent was obtained from the patient for publication of the details of their medical case and any accompanying images.

The authors declare that there are no conflicts of interest regarding the publication of this article.

This research did not receive funding.

Nir Erdinest and Naomi London: writing the first version of the manuscript; Nir Erdinest, Abraham Solomon, Itay Lavy, and Denise Wajnsztajn: substantial contributions to the conception or design of the work; Nir Erdinest, Naomi London, Abraham Solomon, Itay Lavy, and Denise Wajnsztajn: acquisition, analysis, interpretation of data for the work; Nir Erdinest and Naomi London: drafting the work; Denise Wajnsztajn: reviewing it critically for important intellectual content; and Denise Wajnsztajn and Nir Erdinest: final approval of the version to be published.

All data generated and pertinent to this study are included in this article. Further inquiries can be directed to the corresponding author.