Beyond The Dose: Uncovering The Hidden Risk Of Topical Anesthetics

To report a case of a 34-year-old female patient with corneal perforation secondary to topical anaesthetic use.

Corneal perforation is secondary to the use of topical anaesthetics.

Hospital Privado de Comunidad, Mar Del Plata, Argentina

We present a case of a 34-year-old woman who presented to the emergency department with severe ocular pain, photophobia, tearing, and foreign body sensation in the right eye. She had been previously treated at another institution for a suspected "foreign body" with topical gatifloxacin every 3 hours, lubricants, and proparacaine for pain. On examination, uncorrected visual acuity (AVSC) in the right eye was finger counting, uncorrectable with a pinhole. Biomicroscopy showed a clean 9x8mm corneal ulcer without infiltrates, suggesting a neurotrophic ulcer. Treatment was adjusted by discontinuing proparacaine and initiating fortified eye drops every 3 hours, topical insulin every 6 hours, cycloplegic, and doxycycline 100 mg daily. After partial pain relief and slight improvement in ulcer size, a herpetic dendrite was suspected by the anterior ophthalmologist, and oral acyclovir 400 mg five times daily was added. The patient did not attend the following follow-up visit. Eight days later, she was readmitted with worsening symptoms and significant corneal thinning, confirmed by optical coherence tomography. Due to imminent corneal perforation, emergency keratoplasty was recommended but deferred due to limited resources. Five days later, she returned with corneal perforation and positive Seidel's sign, requiring a tectonic corneal patch. Forty-eight hours later, an optical transplant was performed. It was never confirmed whether the patient had discontinued the topical anesthetic.

Prolonged and unsupervised use of topical anaesthetics such as proparacaine and tetracaine can lead to significant complications, including corneal perforation, given the direct toxicity to the corneal epithelium. This predisposes the eye to secondary infections. It is known as a rare complication, but case reports of anaesthetic abuse have been documented. In cases of chronic corneal ulcers, the ophthalmologist should always be highly suspicious of the use of topical anaesthetics. The prognosis depends on two factors: the time in which the diagnosis is reached and the patient's cooperation. There is a high rate of patients who fail to discontinue the anaesthetic.