Quantification of relative afferent pupillary defects induced by posterior sub-Tenon's, peribulbar, and retrobulbar anaesthetics

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.

Correlation between sub-Tenon's anesthesia and transient amaurosis during ophthalmic surgery

PURPOSE

To verify the correlation between sub-Tenon's anesthesia and intraoperative visual loss in ophthalmic surgery.

METHODS

Sixty-four patients underwent phacoemulsification combined pars plana vitrectomy under sub-Tenon's anesthesia. Participants were investigated about their light perception at several time points: before anesthesia, immediately after anesthesia, 10 min after anesthesia without any surgical intervention or microscope illumination, and after the whole surgery. Intraoperative amaurosis was determined as that a patient could not see any light from their operative eye. The incidence rate of amaurosis at different time points and among different anesthetists was analyzed.

RESULTS

The rate of intraoperative amaurosis was 0%, 1.56%, 48.44%, and 95.31% at several time points, respectively: before anesthesia, immediately after anesthesia, 10 min after anesthesia without any surgical intervention or microscope light exposure during the interval, and immediately after the whole surgery, presenting a significantly time-dependent increase (P < 0.01). There was no correlation between the amaurosis and different diseases and anesthesiologists. The amaurosis was transient, and all operative eyes could perceive light on the first postoperative day.

CONCLUSIONS

Sub-Tenon's anesthesia contributes to the intraoperative amaurosis during operation. Temporary interruption of optic nerve conduction by the anesthetic could be a credible explanation. The amaurosis is transient and reversible, requires no additional treatment, and should not be considered as a surgical complication.

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.

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

CONTEXT

The occurrence of amaurosis during ophthalmic anesthesia is well known. The reason for this manifestation has not been studied.

PURPOSE

To investigate the effect of sub-tenon's anesthesia on visual conduction in rabbit eyes.

METHODS

Fifteen right eyes of 15 New Zealand albino rabbits were included. 2% lidocaine hydrochloride and 0.75% bupivacaine hydrochloride (1 ml, 1:1 mixture) was injected in the sub-tenon's space of 8 eyes while the control group (n = 7) was injected with 1 ml physiological saline. Flash visual evoked potentials (FVEP) were performed with Roland reti-scan system before and, 5 min, 15 min, and 5 days after injection. The natural pupillary diameter and minimal pupillary diameter with light reflex were recorded.

RESULTS

In the anesthesia group, N1 latency, P1 latency, and P1 amplitude were 17.13 ± 1.13 ms, 28.25 ± 1.83 ms, 13.45 ± 4.36 μv respectively before injection; 21.75 ± 3.06 ms, 29.63 ± 2.67 ms, 7.24 ± 4.64 μv at 5 min after injection; 22.25 ± 1.39 ms, 29.50 ± 2.51 ms, 7.54 ± 4.47 μv at 15 min after injection, and, 17.75 ± 0.71 ms, 28.13 ± 2.42 ms, 13.17 ± 4.08 μv 5 days after injection. When compared with baseline, N1 latency at 5 min and 15 min after injection showed prolongation (p = 0.019 and p = 0.001, respectively). Likewise, P1 amplitude decreased at 5 min and 15 min after injection (p < 0.001, p < 0.001, respectively). Both N1 latency and P1 amplitude recovered 5 days after the injection. Pupillary light reflex (PLR) constriction amplitude was 35.42% and 0.00% before and at 5 min after injection (p = 0.012). After 5 days it recovered to 33.33%. The FVEP and PLR constriction amplitude did not change significantly after injection in the control group.

DISCUSSION

Sub-tenon's anesthesia was associated with changes in the FVEP and pupullary light reflex in rabbit eyes in our study.

CONCLUSIONS

The data from this study suggested that sub-tenon's anesthesia could reversibly block visual conduction in rabbit's eyes.

Peribulbar versus retrobulbar anaesthesia for cataract surgery

BACKGROUND

Cataract is a major cause of blindness worldwide. Unless medically contraindicated, cataract surgery is usually performed under local (regional) anaesthesia. Local anaesthesia involves the blockage of a nerve subserving a given part of the body. It involves infiltration of the area around the nerve with local anaesthetic. The two main approaches in the eye are retrobulbar and peribulbar. There is debate over whether the peribulbar approach provides more effective, safer anaesthesia for cataract surgery than retrobulbar block.

OBJECTIVES

The objective of this review was to assess the effects of peribulbar anaesthesia (PB) compared to retrobulbar anaesthesia (RB) on pain scores, ocular akinesia, patient acceptability and ocular and systemic complications.

SEARCH METHODS

In the previous version of our review, we searched the databases until December 2007. In this updated version, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (March 2015); MEDLINE (1960 to March 2015); and EMBASE (1980 to March 2015).

SELECTION CRITERIA

We included randomized controlled clinical trials comparing peribulbar anaesthesia and retrobulbar anaesthesia for cataract surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted trial authors for additional information, study methodology and missing data. We carried out a descriptive narrative of results as the included studies used varied methods for reporting the outcomes. We performed a subgroup analysis for globe akinesia.

MAIN RESULTS

We included six trials involving 1438 participants. Three of the six trials had adequate sequence generation while all the trials had unclear allocation concealment There was no evidence of any difference in pain perception during surgery with either retrobulbar or peribulbar anaesthesia. Both were largely effective. There was no evidence of any difference in complete akinesia or the need for further injections of local anaesthetic. Conjunctival chemosis was more common after peribulbar block (relative risk (RR) 2.11, 95% confidence interval (CI) 1.46 to 3.05) and lid haematoma was more common after retrobulbar block (RR 0.36, 95% CI 0.15 to 0.88). Retrobulbar haemorrhage was uncommon and occurred only once, in a patient who had a retrobulbar block.

AUTHORS' CONCLUSIONS

There is little to choose between peribulbar and retrobulbar block in terms of anaesthesia and akinesia during surgery measuring acceptability to patients, need for additional injections and development of severe complications. Severe local or systemic complications were rare for both types of block.

Visual impact of sub-Tenon anesthesia during combined phacoemulsification and vitrectomy surgery

AIM

To investigate the visual impact of sub-Tenon anesthesia during combined phacoemulsification and vitrectomy surgery.

METHODS

In this prospective case series, consecutive patients who underwent combined phacoemulsification and pars plana vitrectomy (PPV) under sub-Tenon anesthesia between October 2008 and September 2009 were enrolled. The patients were asked whether they could see the light of the operating microscope or not between various surgical steps with their contralateral eye being covered.

RESULTS

A total of 163 eyes of 163 patients were enrolled in this study. After their contralateral eyes were covered, 152 (93.3%) patients said that they could not see any light at least during one of the surgical steps. All eyes recovered to at least light perception on the first postoperative day. The incidence of no light perception during the surgery was not related to demographic factors, including age, gender, or type of ocular diseases.

CONCLUSION

The incidence of no light perception during combined phacoemulsification and vitrectomy under sub-Tenon anesthesia was high in our study. Patients should be duly informed about this temporary but potential intraoperative event.

Systematic Review of Peribulbar Anesthesia Versus Sub-Tenon Anesthesia for Cataract Surgery

Commonly used anesthetic techniques for cataract surgery include peribulbar and sub-Tenon anesthesia. This evidence-based review compares these techniques, with a particular focus on patient comfort, akinesia, and anesthetic complications. A systematic search of the literature revealed that there is a paucity of robust evidence comparing sub-Tenon and peribulbar anesthesia. Based on the best available evidence, there is no significant difference in the efficacy of peribulbar compared with sub-Tenon anesthesia for cataract surgery; however, the potential complications of peribulbar anesthesia are more serious.

Subjective visual perceptions during vitreoretinal surgery under local anaesthesia

PURPOSE

To evaluate the visual experiences of patients during vitreoretinal surgery under local anaesthesia (LA).

METHODS

Prospective questionnaire survey of 80 patients within 30 min of completion of vitreoretinal surgery under LA. Preoperative visual acuity, surgical procedure and its duration, efficacy of the local block, as well as intraoperative perceptions of flashes, colours, movements, and seeing instruments were documented.

RESULTS

A sub-Tenon's block was performed in 62/80 (77.5%) and a peribulbar block in the remainder. Overall, 72 (90%) of patients perceived light at some stage during their surgery. Of these, 51 (70.83%) observed movements, 45 (62.5%) saw colours, 38 (52.77%) saw instruments, and 24 (33.33%) saw flashes. The commonest observations were colourful swirls, black pipes, and the colour red. Most patients found these experiences pleasant or bearable; two found them frightening, and four would like to have been warned preoperatively about them. Preoperative visual acuity, diagnosis, gender of the patient, degree of akinesia, and the duration of surgery did not associate with visual perceptions. Logistic regression analysis showed that younger people were more likely to experience flashing lights (P=0.03) and to see instruments (P=0.04), patients having a sub-Tenon's block to perceive light (P=0.005), and those who did not receive awake sedation were more likely to see instruments (P=0.04).

CONCLUSIONS

Visual experiences are common during vitreoretinal surgery undertaken under LA. Where appropriate, patients should be forewarned about these experiences and reassured that they are not normally frightening.

Peribulbar versus retrobulbar anaesthesia for cataract surgery

BACKGROUND

Cataract is a major cause of blindness worldwide. Unless medically contraindicated, cataract surgery is usually performed under local (regional) anaesthesia. Local anaesthesia involves the blockage of a nerve subserving a given part of the body by infiltration of the area around the nerve with local anaesthetic. The two main approaches in the eye are retrobulbar and peribulbar. There is debate over whether the peribulbar approach provides more effective and safer anaesthesia for cataract surgery than retrobulbar block.

OBJECTIVES

The objective of this review was to assess the effects of peribulbar anaesthesia (PB) compared to retrobulbar anaesthesia (RB) on pain scores, ocular akinesia, patient acceptability and ocular and systemic complications.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 4); MEDLINE (1960 to December 2007); and EMBASE (1980 to December 2007).

SELECTION CRITERIA

We included randomized controlled clinical trials comparing peribulbar anaesthesia and retrobulbar anaesthesia for cataract surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted trial authors for additional information, study methodology and missing data. We carried out a descriptive narrative of results as the methods used by the included stories for reporting the outcomes varied. We performed a subgroup analysis for globe akinesia.

MAIN RESULTS

We included six trials involving 1438 participants. Two of the six trials had a low risk of bias; the remaining four had a moderate risk of bias. There was no evidence of any difference in pain perception during surgery with either retrobulbar or peribulbar anaesthesia. Both were largely effective. There was no evidence of any difference in complete akinesia or the need for further injections of local anaesthetic. Conjunctival chemosis was more common after peribulbar block (relative risk (RR) 2.11, 95% confidence Interval (CI) 1.46 to 3.05) and lid haematoma was more common after retrobulbar block (RR 0.36, 95% CI 0.15 to 0.88). Retrobulbar haemorrhage was uncommon and occurred only once, in a patient who had a retrobulbar block.

AUTHORS' CONCLUSIONS

There is little to choose between peribulbar and retrobulbar block in terms of anaesthesia and akinesia during surgery in terms of acceptability to patients, need for additional injections and development of severe complications. Severe local or systemic complications were rare in PB and RB.

What Can Patients See During Glaucoma Filtration Surgery Under Peribulbar Anesthesia?

PURPOSE

To describe the visual sensations experienced by patients during glaucoma filtration surgery under peribulbar anesthesia and to determine possible risk factors that may affect the visual sensations experienced.

SETTING

King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.

METHODS

In this prospective questionnaire study, 75 consecutive adult patients listed for glaucoma filtration surgery (trabeculectomy or Ahmed tube implantation) under peribulbar anesthesia were interviewed postoperatively about the visual sensations experienced in their operated eye during the surgery.

RESULTS

The mean age of the 75 patients was 59.7 years (range, 27 to 83, SD +/-12.1). Sixty-five patients (86.7%) perceived light perception during the surgery and the overall light intensity fluctuated in 45 patients (60.0%). The mean age of the patients who retained light perception intraoperatively was significantly lower compared with those who lost light perception (58.3 y vs. 68.8 y; P=0.009). Forty-six patients (61.3%) were able to perceive colors, 32 patients (42.7%) perceived movement, 31 patients (41.3%) saw surgical instruments, and 33 patients (44.0%) reported seeing the surgeon's hands or fingers. The severity of glaucoma did not affect the proportion of patients who perceived the various visual sensations. One patient (1.3%) was frightened by his intraoperative visual experience. Of the remaining patients, 53 (70.7%) said the visual sensations did not affect them, whereas 21 (28.0%) found them unpleasant.

CONCLUSIONS

The majority of patients undergoing glaucoma filtration surgery retained light perception intraoperatively and many also experienced various visual sensations. Only 1.3% of patients were frightened by their visual experience.

Visual experiences during cataract surgery: what anaesthesia providers should know

Recently published literature shows that most patients experience a variety of visual sensations during cataract surgery under local anaesthesia. Most patients (80-100%) retain at least some light perception in the operated eye and many also experience a variety of other visual sensations during cataract surgery under regional ophthalmic anaesthesia (retrobulbar, peribulbar and sub-Tenon's blocks) or topical anaesthesia. The visual sensations experienced include perception of movements, flashes, colours, changes in brightness, or the sight of surgical instruments, the surgeon's hands or fingers, or even the surgeon. These findings are clinically significant because 3-16.2% of patients who had cataract surgery under either regional or topical anaesthesia were frightened by their intraoperative visual experience. Fear and anxiety may cause some patients to become uncooperative during the surgery and may also induce a sympathetic stress response that might cause hypertension, tachycardia with myocardial ischaemia, hyperventilation or an acute panic attack. These effects are especially undesirable as the majority of cataract patients are elderly and have concurrent medical problems. Besides increasing the risk of intraoperative complications, a frightening visual experience may decrease patient satisfaction. Appropriate preoperative counselling has been shown to be effective in reducing the patients' fear. As most patients retain some visual function during cataract surgery under local anaesthesia, anaesthesia providers should be mindful of this phenomenon and offer appropriate preoperative information and counselling to their patients.

Ophthalmic regional anaesthesia

PURPOSE OF REVIEW

To summarize recent knowledge concerning ophthalmic regional anaesthesia.

RECENT FINDINGS

Ophthalmic regional anaesthesia has changed considerably over the past few years. Alternatives to retrobulbar anaesthesia have been proposed to reduce the number of complications without detriment to efficiency. Finally new local anaesthetics have been adopted and the indications have broadened, especially in vitroretineal surgery.

SUMMARY

New developments in ophthalmic regional anaesthesia are presented in this review. Different methods, indications and side effects are described in order to facilitate the clinician's choice, without any claim to single out an ideal technique.