Subtenon Anaesthesia Complications: Penetrating Eye Injury As Un Unforeseen Risk (2 Case Reports)

To report two penetrating injuries following subtenon anaesthesia for cataract surgery

Cataract centre

Two patients (fifties) underwent subtenon anaesthesia for routine cataract surgery.

The first patient was myopic and had a history of rheumatoid arthritis. She reported pain at the time of the anaesthesia which was administered by a consultant anaesthesist. The operating Ophthalmologist felt that the eye was soft but attributed this to the myopia. The operation was completed without any issues. However, the patient reattended the next day with almost complete loss of vision (Hand movements - post op, 6/9 pre op). It was noted that the macula looked pale and felt that there had been a macula related branch retinal occlusion. She subsequently developped an inferior retinal detachment and was noted to have a track line of retina laceration from the ora to the macula. She underwent successful retinal detachment surgery. However the vision remained poor - hand movement. 

The second patient was due to have routine cataract surgery. Subtenon anaesthesia was administered by a consultant anaesthesist. The eye felt soft at the start of cataract surgery, however, the phacoemulsification was concluded without any issues. The patient reported poor vision the following day (6/60 - post op, 6/18 pre op). She was noted to have submacular haemorrhage, retinal laceration temporal to the macula and a retinal detachment. She underwent successful retinal detachment repair- however her post op vision remains poor at 6/60 post op. 

Subtenon anaesthesia is believed to be safe compared to peribulbar/retrobulbar anaesthesia. 

The subtenon cannulas used in both of those cases had an abrupt bend which does follow the contour of the globe. 

In combination with possible poor techniques, these can have lead to the devastating ophthalmic injuries which both involved the macula. 

It is important to be aware of the possibility of the above complications especially from the anaesthesist perspective. 

The intra operative findings of unusually soft eye and post operative loss of vision should direct the Ophthalmologist towards a rare but serious Ophthalmic injury following sub tenon anaesthesia.