Abstract
Purpose: :
to compare the analgesic efficiency of a viscoanaesthesic product including some licocaine 1 % in comparison with a simple topical anaesthesia by tetracaine 1% collyrium and the possible endothelial toxicity of both therapeutic procedures.
Methods: :
it's a prospective study, including 102 patients, each having standard phacoemulsification by the same surgeon from 24th May to 20th July 2005. There’s 2 distinct anaesthetic methods : in group 1 (51 patients) simple topical anaesthesia by tetracaine collyrium (instillation of a drop of oxybuprocaine 0.4% then 3 drops of tetracaine 1% 5 minutes before operation), in group 2 (51 patients) use of viscoelastic including lidocaine 1 %. The elements studied was : patients’ages, gender, side operated, time of operation, final stitch or not, power and the types of implants used, possible complication, pains felt by the patients during the operation (analogic pain ladder levelled from 0 to 10) and finally, specular endothelial measures before and after operation (from a fortnight to 1 month after operation).
Results: :
The mean age was the same (group 1 : 72,5, group 2 : 72,1), the operation time also : 10,4 mn in group 1 (7 to 15 mn) and 11,2 mn in group 2 (7 to 20 mn). The proportion of women was exactly the same 28/51 patients (54,9 %). The percentage of final stitches was 33,3 % (17/51 cases) in the 1st group and 43 % in the 2rd one (22/51). No operation complication has been noticed. The average power of the implants (soft iol with injector) is 20,99 D in group 1 (13 to 27 D) and 22 D in group 2 (14 to 30 D).
The results at the analgesic level are the same (p=0.5 at t test) with an average pain of 1.27 in group 1(0 to 8) and 1.25 in group 2 (0 to 6).
The preoperative endothelial specular measures are the same : 2491,13 cell/mm² for group 1 (1374 to 3229 cell/mm²) and 2503,5 cell/mm² in group 2 (1314 to 3236 cell/mm²). However, postoperative endothelial specular measures, are 2284 cell/mm² in group 1 (705 to 3074 cell/mm²) and 2000,2 cell/mm² in group 2 (826 to 2960 cell/mm²) with a statistically significant difference (test t with p=0.0014). The percentage of postoperative endothelial cell loss equals an average 8,65 % in group 1 (0 to 60,48 %)versus 20,3 %in group 2 (1,32 to 59,16 %) with, there again, a statistically significant difference (test t p<0.0001).
Conclusions: :
if both topical anaesthesia methods seem the same in the pure analgesic result, it is, by dint of an endothelial toxicity, abnormally high, of the viscoanaesthesic involving lidocaine 1 %, with an average endothelial loss of 20,3 % in the group studied in comparison with a loss of 8,65 % in the control group.
Keywords: cataract • clinical (human) or epidemiologic studies: outcomes/complications • treatment outcomes of cataract surgery