The efficacy of calcium gluconate in ocular hydrofluoric acid burns

1 Although calcium gluconate (CG) is recommended in the treatment of hydrofluoric acid (HF) eye burn its efficacy seems to be controversial, and controlled human or animal studies are limited. The study's objective is to compare the efficacy of 1% CG and normal saline irrigation for the treatment of HF eye injury in animals.

2 0.05 ml 2% HF was instilled to anesthetized rabbit's eyes. One minute later, four treatment groups were studies: (1) irrigation with normal saline followed by topical antibiotics, corticosteroids and cycloplegics for 48 h (n=10); (2) irrigation with 1% CG followed by the same topical treatment (n=9); (3) as group 1 and 1% CG drops over 48 h (n=10); (4) as group 3, and injection of 1% CG subconjunctivally after irrigation (n=9).

3 Corneal erosion area, corneal haziness, conjunctival status, vascularization (pannus) and acidity were assessed before injury, immediately after intitial treatment and 1, 2, 7 and 14 days thereafter by slit lamp aided by fluorescein staining.

4 Conjunctival pH dropped from 6.0 - 6.5 to 2.5 - 3 after injury and increased to 6 - 6.5 after irrigation. Corneal erosion: smaller in groups 2, 3, significantly so at 2 days, but not different at 14 days. Corneal haziness: more severe in group 4, at 14 days, insignificant. Conjunctival damage: significantly worse in group 4 at 2, 7 and 14 days. Pannus appeared in 2 - 4 eyes in each group.

5 It seems that for HF injury 1% CG did not have any significant advantage over saline irrigation and topical treatment only. It might have some initial and temporary effect on healing process especially that involving erosion. Given subconjunctivally, 1% CG may be toxic and worsens clinical outcome.