Corneal Inflammation From Pine Processionary Caterpillar Hairs

Anterior segment optical coherence tomography characteristics and management of a unique spectrum of foreign bodies in the cornea and anterior chamber

Purpose

To report anterior-segment optical coherence tomography (ASOCT) characteristics of different types of corneal and anterior chamber (AC) foreign bodies (FBs) and their usefulness in diagnosis and management.

Methods

This is a retrospective descriptive clinical study involving 11 eyes of 11 patients who presented at the outpatient department of a tertiary ophthalmic care center from January 2017 to January 2022. All patients had a diagnosed or suspected corneal FB. All participants underwent a comprehensive ophthalmological examination, followed by slit-lamp photography and ASOCT. FB removal was done where required by an external, internal, or combined approach.

Results

The mean age of patients was 28.2 (7-53) years. Ten were male, and one was female. Seven patients had a definitive positive history of injury; in one, there was a history suggestive of trauma, one had the post-operative complication of scleral buckling surgery, and two patients had a history of insect fall in the eyes. Three patients had acute, four had sub-acute, and four had chronic presentations. Descemet's membrane (DM) breach was suspected in three cases of deep FB, which was later confirmed on ASOCT. In two cases, DM was presumed to be intact clinically, but ASOCT showed an AC penetration. The FB was removed in seven patients, one via slit-lamp, one via an external approach, two via an internal approach, and three via a combined approach.

Conclusion

ASOCT facilitates non-invasive rapid imaging of ocular tissue at various depths, provides an accurate assessment of FB characteristics, and thereby serves as an additional tool in our armamentarium for diagnosis and management of deep corneal and AC FBs.

Vertical scan imaging of Anterior Segment Optical Coherence Tomography for descemet anchoring caterpillar seta: A case report and review of literature

Purpose

To report Anterior Segment Optical Coherence Tomography (ASOCT) characteristic and its usefulness in the case of Descemet's membrane (DM) anchoring caterpillar seta, highlighting the importance of vertical scans of ASOCT in detecting and delineating the deep seta and its anterior chamber (AC) penetration.

Observation

A 30-year-old male patient presented with complaints of foreign body sensation and watering in the left eye after falling of an insect. Slit-lamp examination showed the presence of two caterpillar hairs, one embedded in the superficial conjunctiva and the second one embedded in the corneal stroma. Conjunctival hair was removed leading to the resolution of symptoms. ASOCT was done for deep corneal hair which showed DM breach and AC protrusion in volume vertical scans. ASOCT scan on follow-up visit showed migration of seta in AC. Deep seta being inert was not removed and the patient was closely followed.

Conclusion

and IMPORTANCE: To the best of our knowledge, this is the first case reporting vertical scan imaging of caterpillar seta and showing AC migration of seta on ASOCT.

Ocular complications of oak processionary caterpillar setae in the Netherlands; case series, literature overview, national survey and treatment advice

During early summer 2019, the Netherlands experienced an outbreak of the exotic oak processionary caterpillar. The vast number of caterpillars, which live in large nests on oak trees before they turn into moths, possess thousands of small, barbed hairs (setae) that are disseminated with the wind. The hairs cause a range of primarily dermatologic problems. However, Dutch ophthalmologists started reporting patients with ophthalmologic complaints caused by the penetrating hairs of the oak processionary caterpillar. This paper focuses on the ophthalmologic complications caused by the caterpillar hairs. We collected a series of four cases with reports ranging from a corneal erosion with hairs lodged into the cornea, to a sterile endophthalmitis in which hairs were found in the vitreous. A literature review for similar cases was performed using the PubMed and Embase database. Together with the Dutch Ophthalmic Society (Nederlands Oogheelkundig Gezelschap, NOG), a national survey was issued to determine the scale of this new problem. This showed that oak processionary caterpillar related complaints are primarily limited to the south of the Netherlands. Suggested ophthalmic treatment guidelines are presented. With the next summer at the doorstep, and limited preventative measures against the caterpillar hairs, we expect a new wave of ophthalmologic complaints coming year as well.

Human exposure to larvae of processionary moths in France: study of symptomatic cases registered by the French poison control centres between 2012 and 2019

CONTEXT

Contact with the setae of larvae (caterpillars) of pine or oak processionary moths could induce urticarial or allergic reactions in humans. These species are present in France and presently expanding towards highly populated areas due to climate change and/or human-mediated translocations. We aimed to describe the symptomatic cases of exposure to processionary larvae in France.

METHODS

We conducted a retrospective study of symptomatic cases of exposure to processionary larvae registered by the French poison control centres between 1 January 2012 and 31 July 2019. We reviewed all medical records coded with the agent "larvae".

RESULTS

Of the 1274 included cases, 59% and 27% corresponded to pine and oak processionary larvae, respectively; the 14% remaining cases concerned unspecified processionary larvae. While the annual number of cases due to pine processionary larvae fluctuated during the study period, cases associated with oak processionary larvae increased steadily. Most of the annual cases occurred between January and May for pine processionary larvae, and April and August for oak processionary larvae (with a peak in March or June, respectively). Among the 1022 cases for which information was available, the sex ratio was 1.2 and the median age was 11 years old. Skin symptoms were reported by 96,3% of the cases, such as pruritus or urticaria. The severity was mild in 96.3% of cases, moderate in 3.5%, and severe in 0.2% (two cases). Ocular or oral exposures led more frequently to severe symptoms than dermal ones (respectively 31% and 18% vs. 2% of cases, p < 10^-3).

CONCLUSION

Since processionary moth larvae exposure is a growing health concern, which can cause severe injuries particularly after ocular or oral exposures, the population, and the professionals should be informed of existing recommendations to avoid exposure and measures to be taken after being exposed.

Comparison of Different Types of Corneal Foreign Bodies Using Anterior Segment Optical Coherence Tomography: A Prospective Observational Study

PURPOSE

The present study highlighted the value of anterior segment optical coherence tomography (AS-OCT) for different types of corneal foreign bodies in humans.

METHODS

This study was a prospective observational study. The patients included were divided into two groups. If the patients were directly diagnosed based on eye injury history and slit-lamp examination, then they were assigned to Group A. Otherwise, the patients were assigned to Group B. We compared and described the characteristics of the corneal foreign body in both groups using AS-OCT.

RESULTS

From October 2017 to January 2020, 36 eyes of 36 patients (9 females and 27 males) with a mean age of 37.8 ± 11.7 years were included in the study. Patients in Group A were the majority and accounted for 72.2% (26/36). High signals on AS-OCT images were the main constituent and accounted for 92.3% (24/26) in Group A and 70.0% (7/10) in Group B. Most of the patients in Group A, 96.2% (25/26), had clear boundaries. A blurred boundary was observed in 70.0% (7/10) of the patients in Group B. The foreign bodies on AS-OCT images had key characteristics of a high signal followed by a central zone shadowing effect and a low signal followed by a marginal zone shadowing effect. Further, all of the lesions could be directly located in Group B, and 92.3% (24/26) of the patients in Group A did not have directly located lesions. Six representative cases are described in detail.

CONCLUSIONS

AS-OCT is a valuable tool in the diagnosis and management of corneal foreign bodies, especially for unusual corneal foreign body.

Comparing in-vivo confocal microscopy and ex-vivo light and scanning electron microscopy images of the hairs of the pine processionary caterpillar embedded in the cornea: Report of three cases

This report describes three cases of pine processionary caterpillar hairs (setae) embedded in the cornea: one in a 69-year-old man with acute keratouveitis, a second case in a 65-year-old man with an epithelial defect and a stromal infiltrate, and the third case affecting a 54-year-old woman with mild keratitis. The two first patients had one hair embedded in the anterior corneal layers while the last one had several hairs deeply embedded in the stroma. By comparing in-vivo confocal microscopy (IVCM) with ex-vivo light microscopy (LM) and scanning electron microscopy (SEM) images, the morphology of the setae was identified and confirmed.

Fungal Keratitis, or Misled by a Small Insect?

The pine processionary caterpillar is an insect that has multiple small, thin hairs around its body as a defense mechanism. These hairs have a hazardous effect on ocular structures and cause a broad range of reactions from conjunctivitis to endophthalmitis, referred to as ophthalmia nodosa. The diagnosis of the disease is based on the patient's history and the detection of the hairs on ocular structures. In this report, we present a patient with ophthalmia nodosa misdiagnosed as fungal keratitis, and the actual diagnosis was made by in vivo confocal microscopy. We also would like to increase awareness among ophthalmologists about the disease which has a growing distribution area due to climate change.

In vivo confocal microscopy of pine processionary caterpillar hair-induced keratitis

PURPOSE

Multimodal imaging of processionary caterpillar hair-induced keratitis with anterior segment optical coherence tomography and in vivo confocal microscopy.

METHODS

Case report.

RESULTS

A 25-year-old woman presented with acute keratitis induced by multiple tiny processionary caterpillar hairs. She initially experienced severe pain and moderate vision loss, which gradually improved within a few weeks. Diagnosis was confirmed by in vivo confocal microscopy showing a pathognomonic image strictly comparable with ex vivo microscopy photography.

CONCLUSIONS

To the best of our knowledge, this is the first case of corneal in vivo confocal imaging of a caterpillar hair with confirmation by ex vivo microscopy.