Panretinal photocoagulation (PRP) is tolerated well by most patients u
sing topical anaesthesia alone, though there are a significant number
of patients who experience pain. Additional local anaesthesia alternat
ives for these patients include retrobulbar, peribulbar or subconjunct
ival injection. Deep introduction of a sharp needle may rarely cause d
amage to orbital structures, whereas no-needle sub-Tenon irrigation of
local anaesthetic solution to the posterior Tenon's space theoretical
ly avoids these risks. A one-quadrant, inferior-nasal, sub-Tenon deliv
ery of 1.5-2 ml plain 2% lignocaine was administered and PRP performed
on 12 eyes of 12 patients who were previously intolerant of PRP by to
pical anaesthesia alone. To assess the efficacy of anaesthesia, patien
ts mere asked to score pain, using a visual analogue score chart grade
d from 0 to 10. If patients mere unable to see the chart, or read the
accompanying text, a verbal explanation and description of the scoring
chart was performed. Where PRP was performed with topical amethocaine
1% alone, pain scores were graded as median 8, mean 8.5 and range 6-1
0. The administration of sub-Tenon anaesthesia was well tolerated with
a median pain score of 1.5, mean 1.9 and range 0-5. PRP after sub-Ten
on administration was successfully completed in 11 of the 12 patients
with a median pain score of 1.5, mean 1.8 and range of 0-9. The range
was wide due to one patient with a high pain score who was intolerant
of PRP in spite of the sub-Tenon delivery. Assessment of pain scores d
emonstrates significantly better anaesthesia with sub-Tenon irrigation
than topical treatment alone (p<0.005, Wilcoxon ranked sign test). If
a patient tolerates PRP with simple topical anaesthesia then this is t
he method of choice. Topical anaesthesia is non-invasive, though if pa
in is experienced, one-quadrant sub-Tenon anaesthesia can provide effe
ctive anaesthesia for PRP with the benefit of seeking to avoid the ris
ks of sharp needle techniques.