Relative frequencies of ophthalmia neonatorum and congenital nasolacrimal duct obstruction

I appreciate the useful article from Maqsood and Mahmood on the identification and diagnosis of herpes simplex ophthalmia neonatorum.¹ As McKechnie and Snelson suggest in their response, a key differential for ‘sticky eye’ in the neonate is congenital nasolacrimal duct obstruction.²

A large cohort study of all children in Olmsted County, Minnesota, found that the prevalence of congenital nasolacrimal duct obstruction was 11.3%. Of these cases, over 90% were identified in primary care.³

Ophthalmia neonatorum however is comparatively rare. A survey sent to members of the American Association for Paediatric Ophthalmology and Strabismus found that most ophthalmologists encountered fewer than five cases per year. Of these cases, the most common causative organism was Chlamydia trachomatis.⁴

The diagnostic challenge for the GP is clear. While they will see numerous cases of congenital nasolacrimal duct obstruction, they will rarely encounter ophthalmia neonatorum. From the literature it appears that herpes simplex ophthalmia neonatorum is relatively uncommon even for specialists working in a more selected population.

Given this difficulty, the pragmatic approach of referral of all cases suspicious for infection, as suggested by McKechnie and Snelson, is prudent. Prompt secondary care assessment would then allow timely and effective treatment to prevent sight-threatening complications.

• © British Journal of General Practice 2021