Ocular Bee Injuries

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Article initiated by:

Erich P. Horn, MD MBA, Sarah Madison Duff-Lynes, MD

All contributors:

Vatinee Y. Bunya, MD, MSCE, Koushik Tripathy, MD (AIIMS), Grant A. Justin, MD, Sarah Madison Duff-Lynes, MD, Erich P. Horn, MD MBA, Masako Chen, MD, Grayson W Armstrong MD MPH

Assigned editor:

Grayson W Armstrong MD MPH, Masako Chen, MD

Review:

Assigned status Up to Date

 by Grayson W Armstrong MD MPH on September 29, 2024.

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Contributing Editors:	add

Summary

• Ocular bee and wasp stings have a diverse range of presentations and complications, including: Toxic Keratopathy, Optic Neuritis, Toxic Scleritis, Toxic Endophthalmitis, Glaucoma, and Cataracts.

• For the primary care or emergency department provider, we recommend that the patient has urgent consultation with an Ophthalmologist.

• If the sting to the eye occurred seconds to minutes prior to presentation, the stinger should be immediately removed to limit venom delivery. If the stinger has been present for longer, the necessity for removal is heavily debated as the venom has already been fully expressed . At that point, the barbed stinger may be treated as a foreign body with complete removal if possible. Ideally the stinger should be removed at a slit lamp, making sure to remove all parts of the stinger.

• Consider treating with a Topical Antibiotic, a Topical Steroid, and a Topical Cycloplegic. Additionally, the authors of this article recommend an Oral Steroid. For the treatment of ocular bee stings, oral or topical antihistamines are not routinely described in literature, but could be considered in certain cases.

• Close follow-up is recommended in all cases, as some cases may worsen rapidly over the first several days.

• For the purposes of tetanus prevention, bee stings can be considered “clean." However, if a patient is due for a tetanus booster or has never received a tetanus vaccine, it should be given at the time of presentation.

Ocular Bee and Wasp Stings

Ocular bee and wasp stings, including stings to the cornea, conjunctiva, sclera, and eyelids, may be devastating to ocular health and visual function. The data published on stings to the eye is limited, mostly consisting of case reports and a few case series, thus there remains a need for further studies.  

While wasps and bees are both members of the Hymenoptera order of insects, their venoms differ, thus one would expect their stings to result in distinct presentations. Some have postulated that wasp stings are worse than bee stings. However, many articles fail to report the type of insect responsible for the “bee sting.” For the purposes of this article, wasp stings and bee stings will be grouped together unless stated otherwise.

Bee and Wasp Stingers

Studies have reported on the biomechanical properties of bee and wasp stingers, which use a pair of lancets (thin piercing part of the bee or wasp) which move back and forth within the stylet while stinging prey. Venom is released through an opening between the lancets. The stinger is held inside the rear end of the abdomen of the bee or wasp prior to stinging a victim. The stinger has barbs which saw through the tissue of the victim being stung. While bees and wasp stingers have similar functions, the two differ in a few notable ways.

Bee stingers use the barbs to saw into the tissue of the victim, but get caught and anchored into the tissue, making it difficult to remove. When a honey bee has to pull away, the stinger may get lodged in the victim as a result and be town away from the bee's abdomen, sometimes also pulling internal organs out of the bee. The honey bee often dies as a result of this sting.

By contrast, wasp stingers usually do not get lodged permanently into the victim. This allows the wasp to sting multiple times, and survive the encounter.

Common Ocular Bee and Wasp Sting Presentations

Ocular bee and wasp stings have a diverse range of presentations and complications, including: Toxic Keratopathy, Optic Neuritis, Toxic Scleritis, Toxic Endophthalmitis, Glaucoma, and Cataracts. Other presentations may include: Toxic Endophthalmitis, subconjunctival inflammation, and/or eyelid swelling and inflammation.

Toxic Keratopathy

History, Physical Examination, and Symptoms

Patients typically describe a painful eye with blurry or diminished vision immediately after being stung on the cornea. Additionally, he or she may have light sensitivity. While some patients may wait to be seen by an ophthalmologist, many immediately present to an ophthalmologist due to the severity of the pain. A stinger may be visible with a slit lamp, but occasionally, the bee's abdomen initially remains as well and is more easily visible.

Signs

• Sterile Corneal Ulcer [typically surrounding an embedded bee stinger deep in the stroma or a penetration track]
• Corneal Edema with Descemet's Folds [may be focal surrounding the ulcer or involve the entire cornea]
  • Edema has previously been described as severe diffuse linear endothelial striae or stellate corneal edema
  • The epithelium may appear to have a "fine network of ridges surrounding the retained stinger" which has previously been called pathognomonic

• +/- Reactive Uveitis, Keratic Precipitates, Ciliary Flush, and/or a Sterile Hypopyon
• +/- Segmental Iris Atrophy
• +/- Overlying Epithelial Defect
• +/- Sluggish or Mid-Dilated Pupil
• +/- Conjunctival Edema and Hyperemia, and/or Subconjunctival Hemorrhages
• +/- Eyelid Swelling
• If corneal edema improves, it frequently becomes a Corneal Scar
• May have long term Endothelial Damage (reduced cell density and polymegathism)

Treatment

Treatment varies and includes surgical removal of the stinger, topical antibiotics, cycloplegics, IOP lowering agents, and steroids.

Optic Neuritis

Several cases of optic neuritis after an ocular or periocular sting have been reported in the literature.  

History, Physical Examination, and Symptoms

Optic neuritis after a sting may not be observed at presentation, but can present hours to days after the initial injury. Patients typically describe a unilateral or bilateral decrease in vision. Several case reports report optic neuritis after bee stings to the conjunctiva or lower eyelid, leading one to postulate that in some cases the venom might have penetrated deeper into the vitreous cavity releasing toxins in the posterior eye. However, bilateral cases after a unilateral sting would suggest an immunologic cause. At this time, risk factors for development of optic neuritis after a sting is not known. Current publications suggest that high dose intravenous or oral steroids may cause complete resolution of symptoms in some cases.  

Signs

• Diminished Visual Acuity [Frequently to Light Perception (LP)]
• + Afferent Pupillary Defect
• Decreased Color Vision
• Optic Disc Edema

Cases

Rosanna de Carmen Zambrano-Infantino reported decreased visual acuity in both eyes after a bee sting to the left lower eyelid. Visual acuity (VA) improved with one gram daily of methylprednisolone for three days.

Choi and Cho reported a sting to the conjunctiva with initially maintained good visual acuity treated with topical steroids. Within twenty-four hours, the visual acuity in the eye that was stung decreased to light perception in the setting of eyelid swelling, conjunctival injection, corneal edema, reactive uveitis and optic disc swelling with an afferent pupillary defect. Treatment with intravenous methylprednisolone (500 mg, followed by 250 mg every 6 hours for 3 days), followed by oral prednisolone (1 mg / kg per day for 1 week), in addition to a topical cycloplegic and topical antibiotic, normalized the visual acuity to 20/20 with resolution of optic disc swelling.

Maltzman et al. reported a bee sting to the lower eyelid in a thirty-two year old that was initially treated with a methylprednisolone dose pack, followed by oral prednisone at one week. This failed to prevent the development of an optic neuropathy, resulting in a final visual acuity of 20/50 with a visual field deficit, despite ultimately being treated with 1000 mg/day of IV methylprednisolone for 5 days. Maltzman et al. also report an eight year old that developed bilateral optic neuritis after a bee sting to the left face that resolved after intravenous and oral steroids.

Additionally, Lai et al. reported a 34-year-old stung by a wasp in the cornea with a resulting unilateral optic neuritis. Despite systemic steroids, (30 mg oral prednisone per day for 1 week), visual acuity did not improve past light perception.

Complications

Corneal Scarring

Corneal scarring frequently occurs after toxic keratopathy from a corneal sting. When corneal scarring is central or significant, a corneal transplant may be considered.

Cataracts

Cataracts appear to be a relatively frequent occurrence in ocular bee and wasp stings. The exact incidence is unknown.

Glaucoma

Short and long term elevations in intraocular pressure have been noted in cases of ocular bee and wasp stings. The exact incidence is unknown. Surgical glaucoma treatment may be necessary.

Secondary Infections

While secondary infections can occur, their incidence appears to be low.

Endothelial Cell Loss

Recently bee or wasp stings to the eye have been shown to cause long term endothelial cell loss. Gürlü and Erda concluded that honeybee venom contains a substance that is toxic to the endothelial cells after following a 25 year-old male one year after a corneal bee sting and finding reduced cell density and polymegathism. Chauhan used specular microscopy to also show endothelial injury and reduced cell density after a bee sting.

Corneal Abrasion

Bee stingers retained in ocular tissues have been found to result in corneal abrasions from friction against corneal epithelium. Careful slit lamp examination of ocular tissues, including tarsal conjunctival tissue, should be performed after stings to remove any retained foreign body material.

Diagnosis

Diagnostic Procedures

If no view to the posterior pole, strongly consider B-scan ultrasonography to rule out vitritis or retinal detachment.  

Cultures of corneal bee stings are not necessary unless the eye provider believes that the sting may be secondarily infected. If the stinger is removed, the eye provider should strongly consider culturing the removed stinger.  

Laboratory Tests

None

Differential Diagnosis

The differential diagnosis for an ocular bee sting is broad and includes anything that could cause corneal opacification, corneal swelling, conjunctival or episcleral injection, or ocular inflammation. The history of exposure to bees and/or wasps is critical to making the correct diagnosis.

Infectious etiologies must be considered. Additionally, non-infectious (sterile) ulcers must be considered, such as those due to exposure keratopathy, or neurotrophic keratopathy, corneal hydrops, or those secondary to autoimmune diseases (such as rheumatoid arthritis), vernal keratoconjunctivitis, vitamin A deficiency, or staphylococcal hypersensitivity.  

Corneal swelling also has an extensive differential but may be a result of decompensation of Fuchs’ endothelial dystrophy, herpetic stromal keratitis, pseudophakic or aphakic bullous keratopathy, iridocorneal endothelial syndrome, or posterior polymorphic membrane dystrophy.  

Risk Factors

No risk factors are known for a worse ocular prognosis from an ocular sting.  

Pathophysiology

Bee and wasp venom are composed of many active components.

Bee venom consists of amino acids, enzymes, and peptides. Main components of bee venom include: Melittin, Apamin, Mast Cell Degranulating (MCD) Peptide, Adolapin, Phospholipase A2 and B, and Hyaluronidase.

Management

There is currently no agreed upon way to treat a corneal bee sting, despite its devastating effects to the eye. Some reports recommend rapid removal of the stinger whenever possible, though it is unlikely that the victim who is stung nor field personnel would feel comfortable removing bee stingers from corneal or periocular tissues. Corneal specialists in countries across the world may see several cases in their career, making it rare, but not extraordinary. Current data is limited to multiple case reports, a few case series, and small, limited literature reviews. No currently published systemic reviews exist.

General treatment

Many providers choose to treat an ocular bee sting with a topical antibiotic and a topical steroid. Consider an oral steroid as early oral steroids may improve the final visual acuity, prevent optic neuritis, and decrease the likelihood of a patient requiring a corneal transplant. If there is anterior chamber inflammation, include a topical cycloplegic. Most clinicians prefer to remove the stingers if possible, although several case reports exist of long term stinger retention in the cornea, lens, and conjunctiva without complication.

Medical therapy

• Topical Antibiotic
• Topical Steroid
• Topical Cycloplegic
• Consider an Oral Steroid

Removal of Stinger

The necessity of bee or wasp stinger removal is debated. About 90% of a bee's venom in injected within the first 30 seconds after the sting and after about a minute, removing a stinger is unlikely to prevent further injection of venom into the eye. Most providers agree that if the stinger can easily be removed in total it should be removed. However, providers disagree on cases where removal may require surgical options. Barbed stinger removal may be difficult. Search should be done for multiple appendages to avoid missing a foreign body and taking multiple trips to the OR or procedure room.

Several case reports report long term retention of singers within the eye and good vision despite the retained stingers.

Medical follow up

Follow-up initially should be within 1 to 2 days, as ocular bee stings may worsen initially over the first several days to weeks, especially if oral steroids are deferred.

Surgery

Once inflammation has subsided, many patients are left with a corneal scar, a cataract, glaucoma, and/or corneal edema. If a gas permeable contact lens or scleral contact lens does not adequately improve vision from a corneal scar and the patient wishes to obtain better vision, a corneal transplant and/or cataract surgery should be considered. Endothelial Keratoplasties (including Descemet's Stripping Endothelial Keratoplasties) may be useful for corneal edema or a Penetrating Keratoplasty may be useful to restore vision from a central corneal scar.

Ahmed et al. described a case of endophthalmitis after a bee sting (toxic verse secondarily infected) that required a pars plana vitrectomy (PPV) with lensectomy. After an additional penetrating keratoplasty, they stated that the patient went from poor vision to 20/80 vision. Thus, in select cases, a PPV may be a valuable option.

An early anterior chamber washout has been described for stings to the eye, especially for wasp stings, as a way to remove the toxins from the anterior chamber.

Prognosis

The prognosis likely depends on the anatomical location of the sting, depth of remaining stinger, type of Hymenoptera insect causing the sting, and practitioner’s choice of treatment.  

Range of visual acuity includes 20/20 vision to many with hand motion, count fingers, and light perception vision.

Ocular wasp stings may have a worse prognosis than ocular bee stings, however there is limited data supporting this.