Dilated pupils and loss of accommodation following diode panretinal photocoagulation with sub-tenon local anaesthetic in four cases

Abstract

Aim. To describe pupillary abnormalities associated with diode laser photocoagulation with subTenon's local anaesthetic. Methods. We describe four cases of tonic pupils following diabetic pantretinal photocoagulation with subTenon's local anaesthetic. Results. Six pupils of four patients became dilated and sustained loss of accommodation with denervation hypersensitivity with 0.1% pilocarpine after undergoing panretinal photocoagulation with a subTenon's local anaesthetic. The numbers of burns were not excessive and in one patient it even occurred after only 1200 laser burns. Conclusion. Diode laser causes histological changes deeper in the retina and the choroid than in Argon laser. Intense diode laser burns may cause damage to the short ciliary nerves traversing the choroid. In the unanaesthetised patient, pain arises when the laser burn hits these nerves and so may protect the eye from excess damage to the nerves. When the eye is anaesthetised with a subTenon's, local anaesthetic damage to the choroidal nerves may occur without the laser operator eing aware that the burns are too intense.