Sir,

We present a case of post-traumatic endophthalmitis following a visit to the dentist. Penetration of the globe occurred after a dental syringe was dropped onto the patient's right eye. Eye protection for both dentist and patient has become very topical, although not universally adopted as standard practice.

Case report

A 68-year-old female patient presented with tenderness and blurring in the right eye following an accident at the dental surgery, where a dental syringe was accidentally dropped onto her right eye during a procedure. She was presented to the eye casualty department a few hours later. No evidence of penetrating injury was found on examination and visual acuity was 6/18 and 6/9. An area of subconjunctival haemorrhage was present below the inferior limbus, but there was no evidence of epithelial injury on flourescein staining. Intraocular pressures were 16 and 14 mmHg in the right and left eyes and there was no evidence of a relative afferent pupil defect. The anterior chamber showed no activity and was deep and well formed while the cornea and lens remained clear. Dilated fundoscopy revealed a single vertical streak of preretinal haemorrhage. No evidence of anterior vitreous haemorrhage was found, and the peripheral retina was normal.

After 24 h the visual acuity in the right eye had decreased to CF and the eye had become painful. The anterior chamber showed a severe fibrinous reaction with 4+ cells. Posterior synechiae were present with an IOP of 50 mmHg, but no iris bombe. She was treated for endophthalmitis and a vitreous biopsy was carried out followed by intravitreal injection of 2.25 mg ceftazidime and 1.5 mg vancomycin. Postoperative IOP was 22 mmHg. The dentist was contacted to get a first-hand account of the incident and he confirmed that a dental syringe, with needle had been dropped onto the patient's eye, having slipped from a tray. The incident occurred before the needle had been used and it was therefore presumed to be sterile.

On day 2 the Gram stain showed Streptococcus sp. and cultures later identified the organism as Streptococcus sanguis (heavy growth). It was resistant only to erythromycin. Light growth of alpha haemolytic Streptococcus was also found, with the same sensitivity spectrum. Specifically, both organisms were sensitive to vancomycin. Consensual testing revealed a right relative afferent pupil defect.

By day 3, she had developed a 4 mm hypopion (Figure 1). B scan ultrasound showed moderate vitreous debris but no evidence of a retinal detachment. The patient was taken back to theatre for a second dose of intravitreal vancomycin (0.2 mg) as well as 4 mg triamcinolone.

Figure 1
figure 1

A 4 mm hypopion developed 3 days after the injury.

Full size image

Phaco and vitrectomy was performed 3 weeks after the original incident. Extensive areas of retinal necrosis were noted and final BCVA was HM in the affected eye.

Comments

Previous reports describe cases of endophthalmitis following penetration by hypodermic and sewing needles.1, 2, 3 In a case series of penetrating injuries in children3 eight of the 84 children presented with an occult penetration. Although we found no evidence of penetration of the globe in this case, we feel the most likely mechanism to be exogenous endophthalmitis, acquired through an occult penetrating injury. Dental needles are fine and flexible and a penetrating injury is more likely to seal and remain occult than would be the case with hypodermic needles.

Normal conjunctival flora consists predominantly of coagulase negative staphylococcus sp.4 and diphtheroids. Although streptococcus sp. has been cultured from the conjunctiva it is not predominant and more common in children than adults.5 S. sanguis and Staphylococcus mutans are the predominant flora in the human oral cavity. They are considered responsible for plaque formation, and in fact make up more than 50% of the plaque mass.6 S. sanguis has only been reported in the conjunctiva of newborns less than 1-week-old.7

However, a retrospective analysis of 773 trabeculectomies found that in the 13 eyes that developed bleb associated endophthalmitis the most frequent causative organisms were Haemophilus influenza and S. sanguis8 (6/13). In these cases, no direct association between the oral flora and endophthalmitis can be inferred.

The British Dental Association has advice sheets recommending the use of eye protection for both patient and practitioner during any invasive procedure. This is used primarily to protect against splatter and not specifically against penetrating injury, although the latter would almost certainly be avoided.

An increasing number of dentists are providing their patients with eye protection during routine procedures.