Glass wool tripod foreign bodies in the eye: first ever reported case series.

We present three cases of unusual corneal/conjunctival foreign bodies that were not visible on standard slit lamp examination. All patients presented with complaints of foreign body sensation in the affected eyes. One patient had visited an ophthalmologist prior to presentation to our center and was diagnosed and treated for conjunctivitis. On slit lamp examination minimal congestion was seen hence, all the patients were diagnosed with conjunctivitis with corneal epithelial defects by the residents. However, because the patients complained of foreign body sensation, fluorescein staining of the affected eye was performed. On examination, the corneas had epithelial defects and linear scratch marks. We suspected a foreign body in upper palpebral conjunctiva (UPC). Examination after eyelid eversion indicated tripod-shaped glassy foreign bodies embedded deep within the UPC. We present cases of an unusual type of glassy tripod-shaped foreign body which may go undetected even on slit lamp examination. Fluorescein staining may aid in the detection of these foreign bodies.

INTRODUCTION

Foreign body sensation in the eye can be due the occasional eyelash that lands inadvertently on the corneal surface to an impact from a high-speed missile of an ejected metal shard. Depending on object the type of injury, the foreign body may penetrate the globe causing serious injury or it may simply resolve without any long-term sequalae.1

Small foreign bodies such as steel, coal or sand may often impact the corneal or conjunctival surface.2

They may be washed along the tear film into the lacrimal drainage system or adhere to the superior tarsal conjunctiva and abrade the cornea with each blink. In such cases the pathognomonic pattern of linear corneal abrasions may be seen.2

Since the conjunctival sac is exposed to the atmosphere, foreign bodies of various types may enter into it.3 The type of foreign bodies that were reported in the conjunctival sac were vast as it is the most common accident occurring in daily life.4

CASE REPORTS

Case 1

A 56-year-old male complained of foreign body sensation in the left eye lasting for 4 days. There was no history of foreign body entering the eye. Best-corrected visual acuity (BCVA) was 6/6 OD, 6/9 OS. On ophthalmic examination, the external adnexa was within normal limits, the bulbar conjunctiva was normal, the cornea showed a small epithelial defect, the palpebral conjunctiva was unremarkable [Figure 1a]. Fluorescein staining indicated a corneal epithelial defect [Figure 1b]. The eyelid was everted for examination of the upper palpebral conjunctiva (UPC) with showed pooling of dye around a tripod-shaped glassy foreign body [Figure 1c–e].

Figure 1

(a) Showing upper palpebral conjunctiva, (b) Showing staining of cornea with fluorescein, (c) Showing upper palpebral conjunctiva with tripod-shaped foreign body, (d) Foreign body in forceps, (e) Tripod-shaped foreign body, (f) Microscopic appearance of the foreign body

Case 2

A 35-year-old male complained of foreign body sensation in left eye for 3 days aftersomething entered the eyes when he was covering an air conditioner duct with an insulating sheet. BCVA was 6/6 OD and 6/9 OS. On ophthalmic examination, the external adnexa was uremarkable, the bulbar conjunctiva was congested and there was an epithelial defect on the superonasal cornea [Figure 2a]. The palpebral conjunctiva was normal [Figure 2b]. A corneal defect was present on fluorescein staining [Figure 2c]. Upper lid eversion, indicated pooling of dye around a tripod-shaped glassy foreign body [Figure 2d and e].

Figure 2

(a) Showing an epithelial defect on the cornea, (b) On eversion of the eyelid, no foreign body is seen, (c) Staining of the epithelial defect with fluorescein, (d) Foreign body under cobalt blue filter, outline of the fluorescein stain, (e) Tripod foreign body picked up with forceps, (f) Microscopic appearance of a foreign body

Case 3

A 38-year-old male complained of foreign body sensation in left eye for 2 days. The patient had no history of any foreign body. BCVA was 6/6 OD and 6/9 OS. The external adnexa was unremarkable, the bulbar conjunctiva had minimal congestion and the cornea appeared normal [Figure 3a]. Upper lid eversion indicated there was minimal congestion and no foreign body was visible [Figure 3b]. Fluorescein staining of the cornea showed linear abrasions [Figure 3c] and UPC showed pooling of dye around the foreign body [Figure 3d and e].

Figure 3

(a) Showing conjunctival congestion with clear cornea, (b) Upper palpebral conjunctiva shows glassy foreign body, (c) Multiple linear abrasions under fluorescein staining, (d) Upper palpebral conjunctiva shows stain pooling around the foreign body, (e) Tripod foreign body removed with forceps, (f) Microscopic appearance of the foreign body

In all cases, the foreign bodies were removed at the slit lamp with a sterile standard forceps. After removal, antibiotic eye ointment and a cycloplegic were prescribed for 24 hours. The cornea was clear 2 days after removal.

DISCUSSION

In the three cases reported here, we noted the presence of linear abrasions with epithelial defects on cornea suggestive of a foreign body lodged in upper palpebral conjunctiva.

In most instances if no foreign body is noticed on upper lid eversion, we assumed that the foreign body may have been dislodged and washed along the tear film into the lacrimal drainage system. However, in these cases a meticulous examination showed the presence of tripod shaped translucent foreign bodies lodged in the superior tarsal conjunctiva.

Normally, a conjunctival foreign body initially causes, an acute inflammatory response involving exudation of plasma and fibrin. This normally dislodges the foreign body. However, in cases of a foreign body with a large surface area and sharp edges (similar to the examples presented here), this mechanism may be insufficient and the foreign body remains embedded. This is followed by a chronic inflammatory response resulting in the formation of a granuloma containing epithelial and foreign body giant cells.5

After examination of foreign bodies under high magnifications [Figures 1ee, 2e and 3e] and through research on the shape and type of material of the foreign bodies we identified it as glass wool. Glass wool is a type of insulating material made from fiberss of glass arranged into a texture similar to wool. It is commonly used as insulation for heating vents and air conditioning ducts in homes and buildings. Hence, it is very common in the surrounding environment and can enter the eye. Glass wool may also irritate the skin and respiratory system.6 Glass wool is inert in nature, hence it did not cause an inflammatory response.

In all three cases reported above a meticulous clinical examination using slit lamp biomicroscopy as well as ancillary investigations such as fluorescein staining and visualization with cobalt blue filter established the presence of translucent tripod foreign bodies lodged in the upper palpebral conjunctiva.