Modification of classification of ocular chemical injuries

A recent paper by Kobayashi and co-workers¹ on temporary amniotic membrane patching for acute chemical burns highlights the difficulty in the consistent classification of this type of injury.

Roper-Hall’s classification of acute chemical injuries to the eye is based on the original classification of Ballen^2,3 and there is little difference between them. However, in neither classification is the grade based on the most severe sign. This immediately leads to the problem of trying to classify an eye having, for example, corneal signs of one grade and conjunctival signs of another. There is also difficulty in grading the conjunctival and limbal injuries.

Dua et al⁴ recognised the problem of assessing limbal stem cell damage and proposed a quasi-analogue scale in order to incorporate intergrade variations. They suggested using limbal fluorescein staining as a marker of limbal stem cell damage. However, their grading scheme is complex and departs significantly from that of Roper-Hall. Although fluorescein staining is a useful sign, it does not necessarily imply limbal stem cell damage or failure and has not been shown to be a better index of limbal damage than perilimbal ischaemia. Importantly, it is also becoming apparent, that both the fornices and mucocutaneous junction of the conjunctiva are important for conjunctival regeneration.^5–7 In fact, Roper Hall stressed the importance of involvement of contiguous areas of the conjunctiva, which may lead to symblepharon formation.⁴

Although there are limitations with Roper-Hall’s classification, it is simple and remains popular. Rather than replace Roper-Hall’s and Ballen’s classification,^2,3 we suggest a modification, which addresses some of the issues raised and makes the classification more robust.

One of the questions that needs to be answered is whether to base the grade of injury upon the most severe sign or on a combination of …