We found statistically significant differences (P < 0.001) between the preoperative P/I ratio [0.40 mm (standard deviation, SD 0.07 mm)] and the postoperative basal ratio [0.33 (SD 0.05)] at 24 h. The P/I ratio at 24 h increased from 0.33 to 0.36 (SD 0.09), a nonsignificant increase (P = 0.45), after instillation of medicated eye drops. No differences were observed between the preoperative [0.40 (SD 0.07)] and 1-month basal values [0.38 (SD 0.07)], and instillation of apraclonidine no longer induced a hypersensitivity response.
CONCLUSIONS:
T3 sympathectomy leads to subclinical pupillary dysfunction with a tendency for miosis, even though this impairment is not generally evident on standard physical examination or reported by patients. This subclinical dysfunction may be caused by injury to an undefined group of presympathetic nerve cell axons in caudocranial direction that communicate with the cervical sympathetic ganglia and whose function is mydriatic pupillary innervation.
http://www.ncbi.nlm.nih.gov/pubmed/22044979