Change in flash visual evoked potentials in New Zealand albino rabbits after sub-tenon's anesthesia

Surgical outcomes of macular hole and epimacular membrane treatment in patients with intraoperative amaurosis under sub-Tenon's anesthesia

Objective

Some patients have been found to develop intraoperative amaurosis under sub-Tenon’s anesthesia. We explored whether these patients have poor surgical outcomes during mid- to long-term postoperative follow-up.

Methods

In this case series, 74 of 85 patients with macular diseases who underwent phacoemulsification combined with vitrectomy under sub-Tenon’s anesthesia developed intraoperative amaurosis. The surgical outcomes at the 2- and 4-month follow-ups in these patients were investigated and compared with the outcomes in patients without amaurosis using best-corrected visual acuity (BCVA), optical coherence tomography (OCT), and pattern visual evoked potential (PVEP).

Results

Both BCVA and the OCT-based macular structure in patients with intraoperative amaurosis showed significant postoperative improvement comparable with that of patients without amaurosis. The presence of intraoperative amaurosis was not associated with either macular hole closure or macular edema regression. PVEP revealed no significant changes in the wave latency or amplitude before and after surgery.

Conclusion

Intraoperative amaurosis following sub-Tenon’s block is commonly seen but does not predict a poor surgical prognosis. When a patient develops amaurosis during surgery, the surgeon should increase patient comfort through verbal communication rather than perform an additional intervention to help relieve the patient’s anxiety.

Incidence and impact factors of intraoperative loss of light perception under sub-Tenon's anesthesia in patients with macular diseases

Purpose

To investigate the incidence and impact factors of intraoperative loss of light perception (LP) under sub-Tenon’s anesthesia in patients with macular diseases.

Methods

Eighty-five consecutive patients received standard phacoemulsification combined pars plana vitrectomy (PPV) under sub-Tenon’s anesthesia. At several checkpoints during the surgery (the end of phacoemulsification, the end of vitrectomy, and the end of surgery), participants were interviewed about whether they had LP or not after removing the influence of contralateral eye and the photo-bleaching effect. In patients treated with retinal photocoagulation, visual experience on laser flashes was evaluated.

Results

Under routine draping, no patients reported loss of LP at all the checkpoints. When the contralateral eye was tightly covered, the rates of LP loss were 84.7%, 97.6%, and 87.1% at the end of phacoemulsification, the end of vitrectomy, and the end of surgery, respectively. When the photo-bleaching effect was also removed, the rates of LP loss were 61.2%, 82.4%, and 56.5% at each checkpoint, respectively, and there were 87.1% (74/85) of patients reporting visual loss in at least one checkpoint. In addition, 76.9% (50/65) of patients could not feel laser flashes during retinal photocoagulation.

Conclusion

Intraoperative loss of LP under sub-Tenon’s anesthesia was a relatively common and reversible event. The conduction block of optic nerve by anesthetic mainly contributed to the visual loss during surgery. Photo-bleaching effect also has some effect on the LP evaluation. Surgeons need to inform and counsel the patients about the intraoperative loss of LP, to prevent any sudden panic attacks in them.