ABSTRACT

Corneal stromal and/or penetrating ocular injuries from pencils and pencil lead are more common in childhood and may lead to intraocular infection or severe intraocular sterile inflammatory reaction. Herein we report 3 children with ocular trauma due to pencil lead injuries. The first case had corneal stromal injury caused by a pencil. In the second case, a pencil perforated the cornea and contacted the iris. In the third case, pencil lead perforated both the cornea and iris and reached the vitreous through the lens zonules. Intracameral triamcinolone (2 mg/0.05 mL) was injected after the pencil lead was removed from the eyeball. Topical anti-inflammatory and cycloplegic drops were prescribed. In conclusion, corneal and especially penetrating ocular injuries from pencil lead may have a good prognosis with the use of appropriate anti-inflammatory and prophylactic antibiotic treatment and follow-up.

Introduction

Organic intraocular foreign bodies generally cause serious inflammatory reaction and infection. The inflammatory reaction induced by inorganic foreign bodies is related to the composition of the object.¹There are few cases in the literature of intracorneal carbon particles^2,3and intraocular penetrating injuries^4,5,6,7,8due to pencil lead. Although it has been reported that the carbon particles from pencil lead may remain dormant in the eye without inducing inflammation for long periods of time,^2,3they have also been reported to cause severe endophthalmitis⁵or endothelial dysfunction and corneal edema.6 In this report we share three cases of pencil lead injury, one with corneal stromal injury and two with intraocular penetrating injuries.

Discussion

Pencil lead is made of a mixture of carbon, clay and animal fat and is surrounded by a wooden sheath. The main component, carbon, is known to usually remain inert in the eye. However, potential toxicity due to the other components is controversial.^5,9The first reported case of intracorneal carbon particles was presented by Jeng et al.²The patient presented due to a chemical injury to the right eye and silver-gray crystalline opacities were observed in the corneal stroma. It was learned that the patient had sustained a pencil injury to the left eye 8 years earlier. However, the patient’s medical records indicated that the injury had in fact been to the right eye. Slit-lamp examination revealed intact corneal epithelium and silver carbon particles in the inferonasal stroma. This demonstrated that carbon particles in the corneal stroma were well tolerated in the long term. Philip et al.³reported a case in which intracorneal carbon particles were observed during routine eye examination in a patient who had sustained a pencil injury to the same eye 3 years earlier. Slit-lamp examination of the right eye revealed anterior stromal scar, though no signs of previous or current inflammation were detected in the intraocular structures.

There are also reports in the literature of pencil lead causing severe inflammatory reaction and endophthalmitis. One reported case underwent corneal suturation and lens extraction following a pencil injury to the right eye. Pencil lead fragments were noted in the vitreous and on the second postoperative day the patient developed endophthalmitis. Although bacterial endophthalmitis was suspected based on clinical findings, a vitreal sample taken during pars plana vitrectomy was culture negative. It was proposed that the wood and aluminum found in pencils may have caused a severe inflammatory reaction.⁵In another case with a history of pencil injury, a suspected conjunctival melanoma was excised and the histopathologic report indicated granulomatous reaction due to carbon particles.¹⁰

Another patient who had sustained a pencil injury to the left eye 4 months earlier presented to an ophthalmologist with a complaint of pain in the left eye for 2 days. Examination revealed a full-thickness corneal scar, a small area of iris atrophy, and a black foreign body resembling pencil lead in the anterior chamber. No inflammatory reaction was observed in the anterior chamber and surgery was performed to remove the foreign body.⁹No anterior chamber inflammation occurred during the 1-month follow-up period (with tapering topical steroid and cycloplegic agent as medical therapy). A case reported by Gül et al.⁸presented with severely reduced vision (CF at 2 m) following ocular trauma by pencil. On slit-lamp examination, corneal perforation and fragments of pencil lead were observed at the wound site. The +4 anterior chamber reaction observed preoperatively continued after corneal suturation and foreign body extraction. Examination on the same day revealed linear carbon accumulation on the endothelial surface, and a pencil lead fragment was visible on the lens after pupil dilation. With hourly steroid therapy, the anterior chamber reaction resolved and the endothelial accumulation and material on the lens disappeared. Han et al.⁶reported a patient with a pencil injury 12 years earlier who presented with stromal keratitis. Antiviral and anti-inflammatory therapy was initiated for a preliminary diagnosis of herpetic stromal keratitis. The patient showed improvement of clinical findings, but at 3-month follow-up, a previously unnoticed foreign body was observed at the anterior chamber angle. The authors believed that the previously inert pencil lead fragment came into contact with the endothelium when it moved, thus triggering an inflammatory reaction. Pencil lead perforated the cornea in our second case and in the third case it perforated both the cornea and iris, reaching the vitreous through the zonules. To prevent a possible inflammatory reaction induced by pencil lead in these patients, triamcinolone was injected into the anterior chamber at the end of surgery, which may be considered possibly beneficial in such cases.

Conclusion

It can be concluded that carbon particles in the cornea are well tolerated in the long term, and that a good prognosis can be achieved in cases of intraocular pencil lead injury with anti-inflammatory therapy, prophylactic antibiotic therapy, and monitoring.