Sir,

We read with great interest the paper by Costa et al1 on the use of subconjunctival triamcinolone acetonide (SCTA) in the management of corneal endothelial graft rejection.

SCTA has been used for corneal transplant surgery.2, 3 However, these have been isolated case reports along with multiple arm therapy in often complicated penetrating keratoplasties (PKPs).4 The effect of SCTA with steroid drops alone could not be ascertained.

We have used 20–40 mg SCTA after failure of steroid drops for at least a week to treat successfully the episodes of rejection in different types of grafts, including DSAEK,4 DALK, and PKP. The outcome was reversal of the rejection and regression of new vessels in all cases.

The only reported side effects were conjunctival ulceration5 and raised intraocular pressure (IOP).6, 7 SCTA has variable duration of action in patients and may depend on technique and site of application along with independent patient variability.

It appears that SCTA acts by locally suppressing the immune response. This local suppression is over a period of time due to the crystalline nature of the drug. The long acting and constant presence of local steroid appears to be an important action as TA is only a moderate strength steroid, four times the strength of hydrocortisone.8 In addition, there may be a steroid-mediated local inhibitory action on the new vessels.9, 10

Subconjunctival steroids appear to achieve intraocular penetration mainly through the temporary incision leakage into the tear film and then through the cornea into the eye.11 There is also scleral and local vessel absorptions, which probably become more important once the incision has healed and if the steroid remains, and is greater in the inflamed than the normal eye.11, 12 We suggest that if SCTA is used for corneal graft rejection, it should be placed as close to the limbus as possible.8, 12

SCTA has been successfully used to reverse neovascularisation in rabbits. This study showed that triamcinolone was present in the cornea for at least 2 weeks after triamcinolone injection.8 As new vessels can mature over 5–6 weeks,13 SCTA should be considered early in the management of corneal new vessel formation, which is resistant to topical steroids.

Finally, we would like to congratulate the authors for their excellent study. We believe that SCTA is a very promising therapeutic approach for corneal graft rejection.