Sub-Tenon's anaesthesia: complications and their prevention

The Infratrochlear Nerve Block Reduces the Incidence of Postoperative Nausea Vomiting in Pediatric Patients Undergoing Strabismus Surgery-A Retrospective Study

Background/Objectives: Strabismus surgery in pediatric patients is associated with a high incidence of postoperative nausea and vomiting (PONV). Patients showing pain are more prone to develop PONV. As the infratrochlear nerve (ITN) block can ameliorate perioperative pain following strabismus surgery, we hypothesized that ITN block may influence PONV in pediatric patients undergoing strabismus surgery. Methods: The medical charts of pediatric patients older than 2 years with exotropia who underwent strabismus surgery under general anesthesia, with or without ITN block, were reviewed retrospectively. The incidence of PONV, intraoperative surgical pleth index (SPI), state entropy (SE), response entropy (RE), the changes in hemodynamics, and perioperative use of metoclopramide and ketoprofen were investigated. Results: The study population comprised 116 patients (58 for the No-block group vs. 58 for the ITN group). The incidence of PONV was significantly lower in the ITN block group compared to the No-block group (5.2% vs. 22.4%, respectively; p = 0.015). The SPI at conjunctiva incision, muscle dissection and traction were significantly lower in the ITN block group than in the No-block group. SE was comparable between the two groups, but RE at muscle dissection and traction was significantly lower in the ITN block group than in the No-block group. The use of metoclopramide and ketoprofen was also lower in the ITN block group than in the No-block group. Conclusions: ITN block reduced PONV as well as perioperative pain in pediatric patients undergoing strabismus surgery.

Life-threatening complications in ophthalmic surgery: a systematic review

Ophthalmic surgical procedures are widely acknowledged for their safety and efficacy. Undoubtedly, advances in ophthalmic surgery, along with the improvement of anaesthetic techniques, have contributed to the reduction in the occurrence of these events. However, although uncommon, systemic severe and life-threatening adverse events can still occur and it is imperative for an ophthalmologic surgeon to have a comprehensive understanding of them to act in terms of proactive prevention, prompt recognition, and optimal treatment, thus maximizing patients' outcomes. Among life-threatening complication following ophthalmic surgery, cardiovascular events represent the most common ones, including a range of different clinical entities: the oculocardiac reflex, potentially leading to haemodynamic instability and asystole; iatrogenic vascular air embolism, in form of venous air embolism or "pefluorocarbon syndrome", which can lead to obstruction of the pulmonary circulation, respiratory distress and cardiovascular collapse; postoperative venous thromboembolism, in the context of which the management of perioperative antiplatelet and anticoagulant therapy has a crucial role. Furthermore, among infectious complications, that are more commonly limited to the ocular tissues, necrotizing fasciitis represents a potentially lethal infection. This review aims to provide an up-to-date, evidence-based overview of potential life-threatening complications associated with ophthalmic surgery, exploring pathogenesis, risk factors, signs, symptoms, and, briefly, management strategies.

Peribulbar vs. incisionless sub-Tenon's blocks: a retrospective cohort study

BACKGROUND

Ophthalmic procedures are increasingly being performed under regional anesthesia techniques such as peribulbar and incisionless sub-Tenon's blocks. The aim is to compare peribulbar block with incisionless sub-Tenon's block in terms of perioperative complications in patients who underwent cataract and vitreoretinal surgeries.

METHODS

The patients who underwent cataract or vitroretinal surgery under peribulbar block or incisionless sub-Tenon's block were included in the study. Two groups were compared each other in terms of anesthesia-related complications.

RESULTS

A total of 125 patients [peribulbar block (N = 48) and incisionless sub-Tenon's block (N = 77)] were included in the study. All basic characteristics and perioperative hemodynamic parameters were similar between the groups. One (0.8%) patient in the peribulbar block developed retrobulbar hemorrhage, whereas there was no major complication in the incisionless sub-Tenon's group (P = 0.389). At 15th minutes after block and at the end of the operation, minor complications including chemosis and subconjunctival hemorrhage were observed significantly lower in the peribulbar block group in comparison to the incisionless sub-Tenon's block group (P < 0.05).

CONCLUSIONS

Minor complications including subconjunctival haemorrhage and chemosis were more common in the incisionless sub-Tenon's block; however, this difference was statistically balanced on the first postoperative day. One patient in the peribulbar block developed retrobulbar hemorrhage, whereas there was no major complication in the incisionless sub-Tenon's block. According to those results, incisionless sub-Tenon's block seems to be a safe and reliable alternative for ophthalmic procedures.

Efficacy of the Subtenon Block in Children Undergoing Strabismus Surgery: A Systematic Review and Meta-Analysis

PURPOSE

To investigate the efficacy of the subtenon block in preventing postoperative complications in children undergoing strabismus surgery.

DESIGN

Systematic review and meta-analysis.

METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Scopus, Web of Science, and clinicaltrials.gov. All randomized controlled trials investigating the efficacy of the subtenon block in children undergoing strabismus surgery were included. Outcomes included severity of pain after surgery, number of children requiring postoperative opioid and nonopioid analgesia, and the incidences of postoperative nausea and vomiting, oculocardiac events, and block-related complications. We pooled continuous outcomes using a random-effects model to calculate the mean difference (MD) and/or standardized MD and corresponding 95% confidence intervals (CI). Dichotomous outcomes were pooled using a random-effect model to calculate the relative risk (RR) and corresponding 95% CI. Risk of bias was assessed using the Cochrane Risk of Bias instrument and quality of evidence was assessed using a Grading of Recommendations Assessment, Development, and Evaluation approach.

RESULTS

Nine randomized controlled trials (607 participants) were included. We found evidence for an effect of the subtenon block in reducing pain at 20 to 40 minutes after surgery (MD -1.9, 95% CI -2.2 to -1.5; high-quality evidence) and on admission to PACU (MD -1.8, 95% CI -2.2 to -1.4; moderate-quality evidence); however, there was no difference in pain scores at 6 hours after surgery. In addition, evidence was found that the subtenon block decreased the number of children requiring postoperative opioid (RR 0.59, 95% CI 0.37-0.92; high-quality evidence) and nonopioid (RR 0.52, 95% CI 0.27-0.98; moderate-quality evidence) analgesia, and the incidences of postoperative vomiting (RR 0.31, 95% CI 0.12-0.7; high-quality evidence) and intraoperative oculocardiac events (RR 0.40, 95% CI 0.26-0.60; high-quality evidence). Other secondary outcomes had low or moderate-quality evidence. Risk of bias was low in six trials and high in three. There were no reports of block-related complications.

CONCLUSIONS

Our findings suggest that the subtenon block reduces the severity of early postoperative pain and the incidences of postoperative vomiting and intraoperative oculocardiac events compared with controls in children undergoing strabismus surgery.

REVIEW REGISTRATION

PROSPERO (CRD42015025443).

Hollow microneedles for ocular drug delivery

Microneedles (MNs) are micron-sized needles, typically <2 mm in length, arranged either as an array or as single needle. These MNs offer a minimally invasive approach to ocular drug delivery due to their micron size (reducing tissue damage compared to that of hypodermic needles) and overcoming significant barriers in drug administration. While various types of MNs have been extensively researched, significant progress has been made in the use of hollow MNs (HMNs) for ocular drug delivery, specifically through suprachoroidal injections. The suprachoroidal space, situated between the sclera and choroid, has been targeted using optical coherence tomography-guided injections of HMNs for the treatment of uveitis. Unlike other MNs, HMNs can deliver larger volumes of formulations to the eye. This review primarily focuses on the use of HMNs in ocular drug delivery and explores their ocular anatomy and the distribution of formulations following potential HMN administration routes. Additionally, this review focuses on the influence of formulation characteristics (e.g., solution viscosity, particle size), HMN properties (e.g., bore or lumen diameter, MN length), and routes of administration (e.g., periocular transscleral, suprachoroidal, intravitreal) on the ocular distribution of drugs. Overall, this paper highlights the distinctive properties of HMNs, which make them a promising technology for improving drug delivery efficiency, precision, and patient outcomes in the treatment of ocular diseases.

Comparison of the effect of 2 mL versus 3 mL sub-Tenon xylocaine injection on akinesia and analgesia in cataract patients at the University of Ilorin Teaching Hospital, Nigeria

PURPOSE

Sub-Tenon anesthesia is a form of local anesthetic techniques used in ophthalmic procedures, especially in cataract surgery. Few studies in our environment have reported the effects of sub-Tenon anesthesia on akinesia and analgesia as well as optimum volumes of anesthetic agents that are required for effective analgesia and akinesia. The objective of this study is to determine and compare the level of analgesia and akinesia and the effect of ocular compressions after sub-Tenon injection of 2 mL versus 3 mL of xylocaine among patients booked for cataract surgery in the University of Ilorin Teaching Hospital (UITH).

METHODS

A cross-sectional comparative study among cataract patients booked for surgery in the Department of Ophthalmology at UITH was carried out from March 2017 to August 2017. A total of 200 cataract patients that met the inclusion criteria were recruited into the study over 6 months. Lists of cataract patients booked for surgery formed the sampling frame. Questionnaires were administered to obtain information on sociodemographic, ocular symptoms, and other histories. Visual acuity was checked, and ocular examination was done with a pen-torch, ophthalmoscope, and slit-lamp examination with 78D. Tonometry and optic nerve assessments were done to exclude any patient with preexisting glaucoma or suspicious disc. About 200 patients were randomly allocated into one of two volume groups (Group 1 had 2 mL sub-Tenon xylocaine injection whereas Group 2 had 3 mL); level of analgesia and akinesia was checked 12 min and 15 min, respectively.

RESULTS

The age range was 20-107 years; mean age for Group 1 was 63.8 ± 12.64, whereas the mean age of Group 2 was 64.14 ± 14.14. There was a slight female preponderance given a M:f of 1:1.4 and more than half of the patients presented with right eye (RE) cataract. Levels of analgesia 12 min after sub-Tenon injections in both groups were similar. However, two patients were found to have severe pain in Group 1, and no patients had severe pain in Group 2. The level of akinesia which was assessed 15 min after injection in both groups was found to be significantly better in Group 2.

CONCLUSION

There was a slight female preponderance with about two-third of the total patients being female and the percentage of females who had no pain was more than the male, more than 50% of the patients had RE cataracts. Sub-Tenon anesthesia whether with 2 mL or 3 mL led to a statistically significant rise in intraorbital pressure (IOP); however, with ocular compression, the IOP was found to decrease below the preinjection pressure in both groups. Levels of analgesia were similar in the two groups, whereas akinesia was statistically better in the group that had 3 mL injection.

Royal College of Ophthalmologists' National Ophthalmology Database study of cataract surgery: report 11, techniques and complications of local anesthesia for cataract surgery in the United Kingdom

PURPOSE

To describe variation in local anesthesia techniques and complications over a 10-year period for cataract surgery in the United Kingdom.

SETTING

Reporting centers to the Royal College of Ophthalmologists (RCOphth) National Ophthalmology Database (NOD).

DESIGN

Retrospective cross-sectional register-based study.

METHODS

Data from the RCOphth NOD were used. Eligible for analysis were 1 195 882 cataract operations performed using local anesthesia between April 1, 2010, and March 31, 2020, in 80 centers.

RESULTS

Overall, topical anesthesia alone was used in 152 321 operations (12.7%), combined topical and intracameral in 522 849 (43.7%), sub-Tenon in 461 175 (38.6%), and peribulbar/retrobulbar in 59 537 (5.0%). In National Health Service (NHS) institutions, 48.3% of operations were topical with/without intracameral vs 88.7% in independent sector treatment centers (ISTCs). 45.9% were sub-Tenon in NHS vs 9.6% in ISTCs. 5.8% were peribulbar/retrobulbar in NHS vs 1.7% in ISTCs. Anesthetic complication rates decreased from 2.7% in the 2010 NHS year to 1.5% in the 2019 NHS year (overall, 2.1% for NHS; 0.2% for ISTCs). Overall anesthetic complication rates were 0.3%, 0.3%, 3.5%, and 3.1% for topical alone, combined topical/intracameral, sub-Tenon, and peribulbar/retrobulbar, respectively. Complication rates were higher for sharp-needle anesthesia (peribulbar/retrobulbar) in patients taking warfarin rather than direct oral anticoagulants (4.8% vs 3.1%; P = .024). Considerable variation was observed between centers on anesthetic choices and anesthetic complication rates.

CONCLUSIONS

Combined topical and intracameral is the most common choice of anesthesia for cataract surgery in the United Kingdom and is associated with lower anesthetic-related complication rates than sub-Tenon and peribulbar/retrobulbar anesthesia. Variation in the anesthetic choice exists between centers and between NHS and ISTC sectors.

Two-stage intra-tenon injection versus sponge-applied mitomycin C-augmented trabeculectomy: a one-year study

PURPOSE

Mitomycin C (MMC) is normally used to avoid scar formation in trabeculectomy. There has been a shift from conventional delivery via soaked sponges to preoperative injection of MMC. This study aimed to compare the effectiveness of a modified two-stage low-dose intra-Tenon injection with soaked sponges of MMC for trabeculectomy over a 1-year follow-up period.

METHODS

This retrospective study enrolled patients with glaucoma undergoing modified trabeculectomy with a two-stage intra-Tenon injection (0.01%, 0.1 mL) or soaked sponges (0.02%) of MMC. In the former group, patients received intra-Tenon injection of MMC (the first stage) at least 4 h before trabeculectomy (the second stage). Patient characteristics, preoperative and postoperative intraocular pressure, antiglaucoma medication use, complications, and post-trabeculectomy surgical interventions were recorded during a 1-year follow-up period.

RESULTS

There were 36 and 35 eyes in the injection and sponge groups, respectively, in 58 patients. The injection group showed significantly lower intraocular pressure (p < 0.05) at every time point except on postoperative day 1 and week 1, fewer medications at the 1-year follow-up (p = 0.018), and a higher complete success rate (p = 0.011) than the sponge group. Both techniques showed a significant reduction in intraocular pressure and medication use at the 1-year follow-up. There were no significant differences in complications between both groups.

CONCLUSION

Our two-stage intra-Tenon MMC injection technique resulted in lower postoperative intraocular pressure, less antiglaucoma medication use, and fewer needling revisions compared to the sponge technique.

Anesthetic Considerations for Cataract Surgery in Patients with Parkinson's Disease: A Narrative Review

Parkinson's disease (PD) is a chronic neurological degenerative disease affecting the central nervous system, which is responsible for progressive disorders such as slow movements, tremors, rigidity, and cognitive disorders. There are no specific recommendations and guidelines for anesthetic management of patients with PD undergoing ophthalmic procedures. This narrative review aims to summarise the anesthetic considerations in patients with PD presenting for cataract surgery.

A case of branch retinal artery occlusion postcataract surgery in an antiphospholipid syndrome patient

A 46-year-old female with preoperative vision 6/18 N18 (LogMar 0.5) in re and posterior subcapsular cataract underwent an uneventful phacoemulsification surgery under a peribulbar block. On the postoperative day 2, she complained of no visual gain in the operated eye. The reported vision was counting fingers close to the face. Through multimodal imaging (MMI), a diagnosis of branched retinal artery occlusion (BRAO) was made. A detailed consultation and history taking with the patient revealed a concealed history of four miscarriages in the past. A detailed systemic blood workup revealed antiphospholipid antibody (APLA) positive. BRAO postuneventful cataract surgery is a devasting outcome for the surgeon and patient undergoing surgery. The report focuses on the importance of taking detailed past medical history and usage of MMI early to rule out and diagnose unexpected scenarios. We suggest BRAO in our patient was a result of emboli formation, which is a common element in APLA-positive patients.

Potential therapeutic strategies for photoreceptor degeneration: the path to restore vision

Photoreceptors (PRs), as the most abundant and light-sensing cells of the neuroretina, are responsible for converting light into electrical signals that can be interpreted by the brain. PR degeneration, including morphological and functional impairment of these cells, causes significant diminution of the retina's ability to detect light, with consequent loss of vision. Recent findings in ocular regenerative medicine have opened promising avenues to apply neuroprotective therapy, gene therapy, cell replacement therapy, and visual prostheses to the challenge of restoring vision. However, successful visual restoration in the clinical setting requires application of these therapeutic approaches at the appropriate stage of the retinal degeneration. In this review, firstly, we discuss the mechanisms of PR degeneration by focusing on the molecular mechanisms underlying cell death. Subsequently, innovations, recent developments, and promising treatments based on the stage of disorder progression are further explored. Then, the challenges to be addressed before implementation of these therapies in clinical practice are considered. Finally, potential solutions to overcome the current limitations of this growing research area are suggested. Overall, the majority of current treatment modalities are still at an early stage of development and require extensive additional studies, both pre-clinical and clinical, before full restoration of visual function in PR degeneration diseases can be realized.

Anesthesia techniques and the risk of complications as reflected in the European Registry of Quality Outcomes for Cataract and Refractive Surgery

PURPOSE

To determine the trends in anesthesia techniques for cataract surgery over the past decade and their relationship to surgical complications.

SETTING

Clinics affiliated with the European Registry of Quality Outcomes for Cataract and Refractive Surgery (EUREQUO).

DESIGN

Retrospective cross-sectional register-based study.

METHODS

Variables include patient demographics, visual acuity, ocular comorbidities, surgery characteristics, intraoperative complications, and postoperative complications for the study period from January 2008, to December 2018. The anesthesia methods registered in the EUREQUO and included in the study are topical, combined topical and intracameral, sub-Tenon, regional, and general anesthesia. Multivariate logistic regression models for each complication were constructed to estimate the adjusted odds ratio (OR) and 95% CIs.

RESULTS

Complete data were available of 1 354 036 cataract surgeries. Topical anesthesia increased significantly over time (from 30% to 76%, P < .001). Sub-Tenon and regional anesthesia decreased (from 27% and 38% to 16% and 6%, respectively, P < .001), and general and combined topical and intracameral anesthesia remained stable (around 2%). Sub-Tenon (OR, 0.80; 95% CI, 0.71-0.91, P < .001), regional (0.74; 95% CI, 0.71-0.78, P < .001), general (0.53; 95% CI, 0.50-0.56, P < .001), and intracameral anesthesia (0.76; 95% CI, 0.64-0.90, P = .001) carried a significantly decreased risk of posterior capsule rupture (PCR), with and without dropped nucleus, compared with topical anesthesia. The risk of endophthalmitis was significantly lower with regional anesthesia compared with topical anesthesia (OR, 0.60; 95% CI, 0.44-0.82, P = .001).

CONCLUSIONS

The use of topical anesthesia for cataract surgery increased over time. Topical anesthesia is associated with an increased risk of PCR with and without dropped nucleus, and endophthalmitis.

Volume-rendered optical coherence tomography angiography during ocular interventions: Advocating for noninvasive intraoperative retinal perfusion monitoring

We aimed to test for feasibility of volume-rendered optical coherence tomography angiography (OCTA) as a novel method for assessing/quantifying retinal vasculature during ocular procedures and to explore the potential for intraoperative use. Thirty patients undergoing periocular anaesthesia were enrolled, since published evidence suggests a reduction in ocular blood flow. Retinal perfusion was monitored based on planar OCTA image-derived data provided by a standard quantification algorithm and postprocessed/volume-rendered OCTA data using a custom software script. Overall, imaging procedures were successful, yet imaging artifacts occurred frequently. In interventional eyes, perfusion parameters decreased during anaesthesia. Planar image-derived and volume rendering-derived parameters were correlated. No correlation was found between perfusion parameters and a motion artifact score developed for this study, yet all perfusion parameters correlated with signal strength as displayed by the device. Concluding, volume-rendered OCTA allows for noninvasive three-dimensional retinal vasculature assessment/quantification in challenging surgical settings and appears generally feasible for intraoperative use.

Anesthesia for ophthalmic surgery: an educational review

PURPOSE

Selecting an anesthetic agent for ophthalmic surgery has crucial implications for the surgeon, anesthesiologist, and patient. This educational review explores the common classes of anesthesia used in ophthalmology. Additionally, we discuss the considerations unique to cataract, glaucoma, strabismus, orbital, oculoplastic, and ocular trauma surgeries.

METHODS

A comprehensive Embase search was performed using combinations of the subject headings "anesthesia", "eye surgery", "ophthalmology" and "cataract extraction", "glaucoma", "strabismus", "vitreoretinal surgery", "retina surgery", "eye injury", and "eyelid reconstruction".

RESULTS

Topical anesthetics are the most commonly used form of ocular anesthesia, used in both an office and surgical setting, and carry a minimal side effect profile. Notably, topical anesthetics offer analgesia, but do not provide akinesia or amnesia. Regional blocks, such as are sub-Tenon's, peribulbar, and retrobulbar blocks, are used when akinesia is required in addition to analgesia. Recently, sub-Tenon's blocks have recently gained popularity due to their improved safety profile compared to other regional blocks. General anesthesia is considered for long, complex surgery, surgery in patients with multiple comorbidities, surgery in young pediatric patients, or surgery in patients intolerant to local or regional anesthetic.

CONCLUSION

Anesthetizing the eye has rapidly evolved in recent years, supporting the safety, efficacy and comfort of ocular surgery. Since there are many viable options of anesthetics available for ophthalmic surgery, a robust understanding of the patients needs, the skill of the surgical team, and surgery-specific factors ought to be considered when creating an anesthetic plan for surgery.

MiRNA 24-3p-rich exosomes functionalized DEGMA-modified hyaluronic acid hydrogels for corneal epithelial healing

The damage of corneal epithelium may lead to the formation of irreversible corneal opacities and even blindness. The migration rate of corneal epithelial cells directly affects corneal repair. Here, we explored ocu-microRNA 24-3p (miRNA 24-3p) that can promote rabbit corneal epithelial cells migration and cornea repair. Exosomes, an excellent transport carrier, were exacted from adipose derived mesenchymal stem cells for loading with miRNA 24-3p to prepare miRNA 24-3p-rich exosomes (Exos-miRNA 24-3p). It can accelerate corneal epithelial migration in vitro and in vivo. For application in cornea alkali burns, we further modified hyaluronic acid with di(ethylene glycol) monomethyl ether methacrylate (DEGMA) to obtain a thermosensitive hydrogel, also reported a thermosensitive DEGMA-modified hyaluronic acid hydrogel (THH) for the controlled release of Exos-miRNA 24-3p. It formed a highly uniform and clear thin layer on the ocular surface to resist clearance from blinking and extended the drug-ocular-epithelium contact time. The use of THH-3/Exos-miRNA 24-3p for 28 days after alkali burn injury accelerated corneal epithelial defect healing and epithelial maturation. It also reduced corneal stromal fibrosis and macrophage activation. MiRNA 24-3p-rich exosomes functionalized DEGMA-modified hyaluronic acid hydrogel as a multilevel delivery strategy has a potential use for cell-free therapy of corneal epithelial regeneration.

Efficacy and safety of trans-sub-Tenon's retrobulbar anesthesia for pars plana vitrectomy: a randomized trial

AIM

To compare the efficacy and safety of trans-sub-Tenon's ciliary nerve block anesthesia and transcutaneous retrobulbar anesthesia in patients undergoing pars plana vitrectomy (PPV).

METHODS

A prospective, randomized, double-blinded clinical trial was conducted at Zhongda Hospital, Affiliated with Southeast University, from February 2021 to October 2021. Patients undergoing PPV were randomly allocated into two groups: the trans-sub-Tenon's anesthesia group (ST group) and the retrobulbar anesthesia group (RB group) in the ratio of 1:1. The ST group received 2 ml ropivacaine through the Tenon capsule to the retrobulbar space, while the RB group received 2 ml ropivacaine via transcutaneous retrobulbar injection. Visual analog score (VAS) was used to evaluate pain during the whole process, including during anesthesia implementation, intraoperatively and on the first day after the operation. Movement evaluation (Brahma scores) and anesthesia-related complications were also noted.

RESULTS

Finally, a total of 120 patients were included in the study (60 in the ST group and 60 in the RB group). There were no significant differences in baseline patient characteristics or surgical features between the two groups. The VAS pain scores for anesthesia implementation were 0.52 ± 0.47 in the ST group and 1.83 ± 0.87 in the RB group (P < 0.001). The VAS scores during the operation were 0.53 ± 0.49 in the ST group and 1.48 ± 1.02 in the RB group (P < 0.001) and those on the first day after the operation were 0.37 ± 0.38 in the ST group and 0.81 ± 0.80 in the RB group (P = 0.002). No patients required supplemental intravenous anesthesia intraoperatively. The Brahma movement scores were 0.70 ± 1.64 in the ST group (scores ranging from 0 to 8) and 2.38 ± 3.15 in the RB group (ranging from 0 to 12) (P = 0.001). Forty-two patients in each group received laser photocoagulation during surgery. Fifteen patients (36%) in the ST group could not see the flashes of the laser, compared to 8 patients (19%) in the RB group (P = 0.087). No serious sight-threatening or life-threatening complications related to anesthesia were observed in either group.

CONCLUSIONS

For PPV, trans-sub-Tenon's ciliary nerve block anesthesia was more effective in controlling pain than transcutaneous retrobulbar anesthesia during the whole surgery process, including during anesthesia implementation, intraoperatively and on the first day after the operation. Additionally, it could achieve better effect of akinesia and was relatively safe. Trans-sub-Tenon's anesthesia could be considered an alternative form of local anesthesia during vitreoretinal procedures.

TRIAL REGISTRATION

The study protocol has been registered at ChiCTR.org.cn on February 2021 under the number ChiCTR2100043109 .

Clinical features, management and outcomes of expulsive choroidal hemorrhage during cataract surgery: 13 years experience from a tertiary eye center

PURPOSE

To study the risk factors, clinical features, management, and outcomes of intraoperative expulsive choroidal hemorrhage (ECH) during cataract surgery.

SETTING

Aravind eye hospital, Madurai, Tamil Nadu, India.

DESIGN

Retrospective hospital-based study.

METHODS

Of the 1167250 patients who underwent cataract surgery between 2008 to 2020, patients diagnosed with intraoperative ECH were included. Demography, ocular and systemic risk factors, visual acuity, type of ocular anesthesia, intraoperative and postoperative records, management, and surgical outcomes were analyzed.

RESULTS

A total of 52 eyes (0.004%) of 1167250 patients had ECH. Of the 52 cases, 43 cases (incidence rate 0.006%) were reported in the years 2008 to 2015 and 9 cases (incidence rate 0.002%) in the years 2016 to 2020. The change in the ocular anesthesia from peribulbar and retrobulbar anesthesia (2008-2015) to sub-Tenon's anesthesia (2016-2020) was associated with a reduced rate of ECH (p-value 0.002). Twenty-eight eyes (53.8%) were having limited ECH and 24 eyes (46.2%) were having full-blown ECH. The visual outcome was better in eyes with limited ECH compared to full-blown SCH in all follow-up visits. The median vision (IQR) before the cataract surgery and immediate postoperative day 1 were 1.30 (0.78 - 2.60) and 2.45 (1 - 2.75) respectively. The median final vision (IQR) after the secondary surgical intervention was 2.2 (0.60 - 2.60).

CONCLUSIONS

This series included 52 eyes with ECH, recognized associations of ECH with different types of anaesthesia as well as with different cataract surgical procedures, and described management of ECH. Postoperative visual outcome was poor.

Analysis of urgent follow up visits and complications after intravitreal injections: a retrospective cohort study

BACKGROUND

Intravitreal injections (IVIs), a common treatment in ophthalmology, result in acute complications and urgent follow-up visits causing significant burden to both patient and physician. We evaluated the incidence of acute complications following IVIs which occurred within seven days of injection.

METHODS

A retrospective cohort study conducted at a private retinal practice, in Cleveland, Ohio. Using the practice management software database, we examined 73,286 injections of patients with unscheduled or urgent visits within 7 days of an injection from August 1st,2018 to August 1st,2020. Data collected included: age, gender, eye, medication injected, diagnosis, reason for urgent follow-up, time between injection and urgent follow-up, and type of anesthesia administered. Data was analyzed using SPSS v.28 (SPSS Inc., Chicago IL).

RESULTS

Study included 73,286 injections, with 441 injections (n = 441) resulting in urgent follow-up visits (0.60%). Mean patient age was 72.1 (± 30.4) years, with 187 male (42.4%) and 254 female (57.6%) patients. IVI medications included: aflibercept (60.3%), ranibizumab (22.4%), bevacizumab (13.4%), dexamethasone intravitreal implant (2%), triamcinolone acetonide (1.6%) brolucizumab (1.59%), fluocinolone acetonide intravitreal implant 0.19 mg (0.2%), and fluocinolone acetonide intravitreal implant 0.18 mg (0.03%) (Table 1). Medications associated with urgent visits included: aflibercept (42.9%), bevacizumab (37.4%), ranibizumab (7.9%), dexamethasone intravitreal implant (6.8%), brolucizumab (2.7%), and triamcinolone acetonide (2.3%) (Table 2). Days between injection and urgent follow-up was on average 3.96 ± 2.14 days. Urgent follow-ups included blurred vision in 164 patients (37.2% of urgent visits), flashes, floaters or posterior vitreous detachment (PVD) in 55 (12.5%), pain in 42 (9.5%), 43 (9.8%) corneal abrasions, 33 (7.5%) subconjunctival hemorrhages, corneal dryness or foreign body sensation in 30 (6.6%), endophthalmitis in 20 (4.5%), 18 (4.1%)vitreous hemorrhages, iritis or uveitis in 11 (2.5%), miscellaneous complications in 9 (2.0%), 7 (1.6%) elevated intraocular pressures, choroidal neovascular membrane in 4 (0.9%), 4 (0.9%) retinal detachments or tears, and 2 (0.45%) traumatic cataracts (Table 3).

CONCLUSION

IVIs resulted in 0.60% urgent/unscheduled follow-up visits within 7 days of injection. Most common causes were blurred vision and symptoms of PVD.

Patient and surgeon comfort in vitreoretinal surgery performed with Sub-Tenon's Anaesthesia

Background. Since Stevens first introduced Sub-Tenon's anaesthesia into cataract surgery it has shown itself to be a safe, simple, and efficient technique. The advantages of this type of block are comparable to those of sharp needle anaesthesia and complications are minimal. Several studies have found that the anaesthesia provided by Sub-Tenon's capsule injection is as good as or better for cataract surgery than that achieved by retrobulbar injection, but the efficacy of Sub-Tenon's block in vitreoretinal surgery is less well established. Methods. We performed 50 vitreoretinal procedures; 50 eyes received a Sub-Tenon's injection of a 5 ml mixture (50:50) of lidocaine and ropivacaine, plus 15 IU mL-1 of Hyaluronidase. Results. In 45 cases, only one injection was needed to achieve sufficient anaesthesia and akinesia; in 5 cases a second injection was performed five minutes after the first. Mean surgical time was 45.7 minutes. After surgery, each patient was asked to indicate his value on the VAS pain scale. Mean VAS degree was 2.4. In 7 cases, VAS was > 3 and the pain was successfully managed with the administration of paracetamol in the postoperative period. No light perception was detected at the end of surgery in 33 patients. All cases with 2 injections had no light perception at the end of surgery. Anaesthesia lasted throughout the surgery in all cases. The surgeon performed all surgery comfortably and with no difficulty. Conclusions. According to our experience and to a growing body of evidence, Sub-Tenon's anaesthesia appears to be a safe, simple, versatile, and effective technique and should be considered as a real alternative method of anaesthesia in vitreoretinal surgery.

Sub-Tenon's anaesthesia for modern eye surgery-clinicians' perspective, 30 years after re-introduction

Sub-Tenon's block (STB) is a good technique of local anaesthesia for many types of eye surgery. It has a relatively good risk profile, in that sight- and life-threatening complications appear to be extremely rare. STB has gained popularity in the last three decades, with refinements including different types of blunt metal cannula, plastic cannulae and 'incisionless' approaches. Usage of STB varies significantly across the globe. This narrative review documents the historical evolution of STB techniques, anatomical and physiological considerations, its utility and suitability, complications, explores the current practice and possible future applications.

Treatment of traumatic optic neuropathy using human placenta-derived mesenchymal stem cells in Asian patients

Aim: To assess the safety and feasibility of subtenon transplantation of human placenta-derived mesenchymal stem cells (hPMSCs) in Asian patients with traumatic optic neuropathy. Materials & methods: The survival of retinal ganglion cells in the rat retina was evaluated by monitoring the expression of Tuj1 and Gfap after optic nerve compression. Based on the preclinical data, we conducted a Phase I, open label, single center, nonrandomized clinical trial in four Asian traumatic optic neuropathy patients. The safety and ophthalmologic changes were evaluated. Results: The levels of Tuj1 and Gfap expression were significantly increased in the hPMSC treatment group compared with the sham group, suggesting a protective effect of hPMSCs on the optic nerve and retinal ganglion cells. There was no evidence of adverse proliferation, tumorigenicity, severe inflammation or other serious issues during the 12-month follow-up period. Visual acuity improved in all four patients. Conclusion: The results suggested that hPMSCs are safe and have potential utility in regenerative medicine. Clinical trial registration number: 20150196587 (Korean FDA), 2015-07-123-054 (IRB).

A review of current ophthalmic anaesthetic practice

INTRO

Ophthalmic surgery ranks among the commonest procedures performed worldwide. This review considers the range of anaesthetic techniques available to the modern ophthalmic anaesthetist, and practical considerations to evaluate in different circumstances. There is a brief summary of the main issues pertaining to the common ophthalmic subspecialties and operations.

SOURCES OF DATA

Pubmed.

AREAS OF AGREEMENT

We present a view of contemporary ophthalmic anaesthetic practice as we see it, both from current UK clinical experience, and the available published evidence.

AREAS OF CONTROVERSY

There is an ongoing debate about the safety of sharp needle blocks (SNBs) compared to subtenons and topical techniques, but SNBs still have a role to play, both in specific cases, and in circumstances where resources are limited.

GROWING POINTS

It remains a challenge to provide safe, cost effective anaesthesia to a growing patient base with ever increasing demands and medical comorbidities. There is a continuing trend towards replacing general with local anaesthesia where possible.

RESEARCH

Research in ophthalmic anaesthesia, as in so many areas, has been plagued by heterogeneity and small studies. A coordinated, large scale, multicentred approach to research questions in future would help to guide best practice with more certainty.

Lacrimal dilator-facilitated incisionless vs. standard sub-Tenon's block: a randomized, prospective and non-inferiority comparative study

BACKGROUND/OBJECTIVES

Standard sub-Tenon's block (STB) involves incision (dissection) of conjunctiva and Tenon's capsule with the help of blunt scissors and forceps, insertion of a blunt sub-Tenon's cannula under the Tenon's capsule and injection of local anaesthetic agent. STB is frequently associated with minor complications such as chemosis and postoperative subconjunctival haemorrhage but rare sight and life-threatening complications. To reduce these minor complications, several variations of incisionless STB have been described however, there are no comparative data. One such incisionless STB involves the use of lacrimal dilator which is easily available in the operating theatre. We compared incisionless lacrimal dilator-facilitated with the standard STB for effectiveness, chemosis, and postoperative subconjunctival haemorrhage.

SUBJECTS/METHODS

After obtaining ethical approval, patients scheduled to undergo elective phacoemulsification cataract surgery were enroled to receive incisionless lacrimal dilator-facilitated STB (Group LD) or a standard STB using Wescott scissors and blunt forceps (Group WS). All patients received 3 mL 2% lidocaine without any adjuvant. No sedation was administered. Demographics of the patients, duration of the procedure, analgesia, akinesia, duration of the procedure intraoperative chemosis, and postoperative subconjunctival haemorrhage were compared.

RESULTS

Both groups were comparable for demographic data, duration of the procedure, analgesia, and akinesia (p > 0.05). The severity of chemosis and postoperative subconjunctival haemorrhage were significantly lower in Group LD (n = 32) in comparison to Group WS (n = 31) (p < 0.001).

CONCLUSIONS

Incisionless lacrimal dilator-facilitated STB decreases intraoperative chemosis and postoperative conjunctival haemorrhage in comparison to standard STB. Analgesia and akinesia are comparable in both techniques.

Evaluating the effectiveness of localized sub-Tenon's anesthesia in 23-gauge vitreoretinal surgery

PURPOSE

To evaluate the effectiveness of localized sub-Tenon's anesthesia for pain control during 23-gauge vitreoretinal surgery.

METHODS

Eighty patients were randomly divided into two groups as localized sub-Tenon's (group 1, n = 41) and retrobulbar (group 2, n = 39) anesthesia groups. In group 1, a small volume of anesthetic was injected into the sub-Tenon's capsules at the trocar entry sites. The 23-gauge vitreoretinal surgery was performed in all patients. In both groups, the pain levels during the surgical steps were evaluated using the visual analog pain scale.

RESULTS

Patients in group 1 experienced less pain than group 2 patients did during placement of the trocars and scleral depression (p = 0.041, p = 0.029). Pain during laser photocoagulation was higher in group 1 (p = 0.008). There was no serious complication due to anesthesia or surgery.

CONCLUSION

Localized sub-Tenon's anesthesia is as effective as retrobulbar anesthesia in many steps of vitreoretinal surgery for providing pain control. It can be considered an alternative form of local anesthesia.

Pain during pars plana vitrectomy following sub-Tenon versus peribulbar anesthesia: A randomized trial

Purpose

To compare pain during pars plana vitrectomy (PPV) following topical lidocaine jelly and sub-Tenon anesthesia versus peribulbar anesthesia.

Methods

Prospective, single-center, randomized study. Patients scheduled for PPV for macular hole (MH) or epiretinal membrane (ERM) at the Retina and Vitreous Section of the Department of Ophthalmology, Ribeirão Preto Medical School, University of São Paulo were randomly assigned to one of two groups in a 1:1 allocation ratio. Patients assigned to Group ST received topical anesthesia with 2% lidocaine jelly followed by sub-Tenon anesthesia with 2–4 ml of 1% ropivacaine. Patients assigned to PB received peribulbar anesthesia with 4–6 ml of 1% ropivacaine. After PPV, patients in both groups were asked to rate the level of pain they felt during the entire procedure (including anesthesia administration and PPV) by pointing at a 0–100 Visual Analogue Pain Scale (VAS). Data regarding demographics, patient characteristics and surgical features were also collected.

Results

Fifty-four patients were enrolled in the study (26 in Group ST and 28 in Group PB). Baseline characteristics, including age, gender, and presence of comorbidities, were similar in both groups. The surgery performed was PPV alone in 10 and 14 patients in the ST and PB groups, respectively, and combined phacoemulsification and PPV in 16 and 14 patients in the ST and PB groups, respectively (p = 0.39, Pearson). Surgery duration (mean ± SD minutes) was similar in the two groups (62 ± 12 for ST and 70 ± 20 for PB, p = 0.09, t-Test). No patients needed supplemental topical or intravenous anesthesia during surgery. No sight- or life-threatening complication was observed in either group. VAS score was significantly lower in the ST compared to the PB group (median (interquartile range) was 1 (2.25–0) in the ST group compared to 11.5 (29.75–5) in the PB group, p< 0.0001, Wilcoxon).

Conclusion

In this study of patients who underwent PPV for MH or ERM, topical followed by sub-Tenon anesthesia was more effective in controlling pain during the whole vitrectomy procedure than peribulbar anesthesia. Compared to peribulbar anesthesia which is administered with a sharp needle, sub-Tenon anesthesia administered with a blunt cannula may be associated with a reduced risk of such adverse events as globe perforation, retrobulbar hemorrhage, and inadvertent injection of anesthesia into the optic nerve sheath.

Ultrasound detection of iatrogenic injury during peribulbar eye block: a cadaveric study

Background

Ophthalmic eye blocks, such as retrobulbar, peribulbar and sub-Tenon’s, are traditionally conducted “blind”. Complications are rare but potentially devastating. Life-threatening complications include brain stem anesthesia and local anesthetic toxicity, whereas sight-threatening complications include globe perforation, optic nerve damage and ocular muscle damage. Ultrasound permits a view of orbital structures and can be used to guide needle placement. The ultrasound appearances of unintended local anesthetic injection into vital orbital structures have not been documented. This study aimed to record the ultrasound appearances of unintended injection locations.

Methods

The spherical shape of the eyeballs of three soft-fix Thiel embalmed human cadavers were restored using glycerol. Iatrogenic injury in peribulbar block was then simulated through injection of printers’ ink mixed with Thiel embalming fluid. Ultrasound was used to guide the needles and the tips were redirected to lie within the globe, lateral rectus and optic nerve. Ultrasound images were recorded during injection. The orbital cavities were then dissected via a superior approach to record the location and extent of injectate spread.

Results

Real-time globe rupture, ocular muscle injection and optic nerve injection were visible using ultrasound. Characteristic appearances were identified in each case. Dissection confirmed needle and injection placement.

Conclusions

The ultrasound appearance of block complications is important to document and should be an integral part of regional anesthesia training. This study is the first to provide such images for ophthalmic nerve blocks. It offers ophthalmic anesthetists and ophthalmologists the potential to diagnose severe complications rapidly and accurately with a potential impact on patient safety.

Cardiorespiratory Events Associated With Ophthalmic Surgery: A Single-Center, Retrospective Records Review of 130 775 Patients, 1999–2015

Purpose:

The most recent study of ophthalmic surgery morbidity and mortality was published in 1995, with a patient study population from 1977 to 1988. The present study reports surgical outcomes from a single-center, retrospective analysis of patient records from 1999 to 2015.

Methods:

Three International Classification of Diseases–9-CM codes for cardiorespiratory events were searched in the discharge diagnoses in an eye hospital over a 16-year period. The overall mortality and preoperative risk factors were analyzed, including the type of anesthetic, type of surgery, medical comorbidities, and bradycardia preceding the cardiac events.

Results:

Between February 1, 1999 and October 1, 2015, a total of 130 775 patients presented for ophthalmic surgery. Fifty-nine patients (0.45 per 1000) experienced a cardiorespiratory event. Of the 59 patients, 14 patients had a cardiorespiratory arrest, 9 of whom died during the perioperative period. Of the remaining 45 patients, 29 had significant adverse events needing some form of advanced monitoring, evaluation, and/or intervention. There was a significantly greater prevalence of diabetes among patients who had a cardiorespiratory event ( P < .001).

Conclusions:

The major risk factor associated with ophthalmic surgery morbidity and mortality was diabetes with its associated complications of autonomic neuropathy, nephropathy, and retinopathy. Of the 9 patients who died, 8 were diabetic with proliferative diabetic retinopathy and renal insufficiency/failure. The ninth mortality was secondary to a venous air embolism during ocular air infusion. The adage that “the eye is the window to our overall health” seems to be correct.

Regional Anesthesia for Pediatric Ophthalmic Surgery: A Review of the Literature

Ophthalmic pediatric regional anesthesia has been widely described, but infrequently used. This review summarizes the available evidence supporting the use of conduction anesthesia in pediatric ophthalmic surgery. Key anatomic differences in axial length, intraocular pressure, and available orbital space between young children and adults impact conduct of ophthalmic regional anesthesia. The eye is near adult size at birth and completes its growth rapidly while the orbit does not. This results in significantly diminished extraocular orbital volumes for local anesthetic deposition. Needle-based blocks are categorized by relation of the needle to the extraocular muscle cone (ie, intraconal or extraconal) and in the cannula-based block, by description of the potential space deep to the Tenon capsule. In children, blocks are placed after induction of anesthesia by a pediatric anesthesiologist or ophthalmologist, via anatomic landmarks or under ultrasonography. Ocular conduction anesthesia confers several advantages for eye surgery including analgesia, akinesia, ablation of the oculocardiac reflex, and reduction of postoperative nausea and vomiting. Short (16 mm), blunt-tip needles are preferred because of altered globe-to-orbit ratios in children. Soft-tip cannulae of varying length have been demonstrated as safe in sub-Tenon blockade. Ultrasound technology facilitates direct, real-time visualization of needle position and local anesthetic spread and reduces inadvertent intraconal needle placement. The developing eye is vulnerable to thermal and mechanical insults, so ocular-rated transducers are mandated. The adjuvant hyaluronidase improves ocular akinesia, decreases local anesthetic dosage requirements, and improves initial block success; meanwhile, dexmedetomidine increases local anesthetic potency and prolongs duration of analgesia without an increase in adverse events. Intraconal blockade is a relative contraindication in neonates and infants, retinoblastoma surgery, and in the presence of posterior staphylomas and buphthalmos. Specific considerations include pertinent pediatric ophthalmologic topics, block placement in the syndromic child, and potential adverse effects associated with each technique. Recommendations based on our experience at a busy academic ophthalmologic tertiary referral center are provided.

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.

Local delivery of corticosteroids in clinical ophthalmology: A review

Locally administered steroids have a long history in ophthalmology for the treatment of inflammatory conditions. Anterior segment conditions tend to be treated with topical steroids whilst posterior segment conditions generally require periocular, intravitreal or systemic administration for penetration. Over recent decades, the clinical applications of periocular steroid delivery have expanded to a wide range of conditions including macular oedema from retino-vascular conditions. Formulations have been developed with the aim to provide practical, targeted, longer-term and more efficacious therapy whilst minimizing side effects. Herein, we provide a comprehensive overview of the types of periocular steroid delivery, their clinical applications in ophthalmology and their side effects.

Outcomes and Adverse Events of Sub-Tenon's Anesthesia with the Use of a Flexible Cannula in 35,850 Refractive Lens Exchange/Cataract Procedures

Purpose

To describe our technique of sub-Tenon’s anesthesia and report adverse events and patient comfort.

Setting

Optical Express, United Kingdom.

Design

Retrospective case series.

Methods

The outcomes of 35,850 intraocular procedures (phacoemulsification and implantation of an intraocular lens) were retrospectively reviewed and the incidence of adverse events related to sub-Tenon’s anesthesia was calculated. On the first postoperative day, patients were asked to complete a questionnaire enquiring about their comfort during and after the procedure. The anesthetic solution consisted of a combination of Lidocaine and Hyaluronidase, which was administered into sub-Tenon’s space with a single-use sterile polyurethane 22G x 1” (0.9 x 25 mm) cannula. Mild conscious sedation (midazolam) was used during anesthetic and surgical procedure.

Results

No significant adverse events that would affect the posterior segment of the eye or result in vision loss were recorded. Subconjunctival haemorrhage related to sub-Tenon’s anesthesia was noted in 4.3% of eyes. Five minutes after the administration of sub-Tenon’s block, 80.6% of eyes had no chemosis, 14.8% had chemosis that affected only 1 quadrant of the eye and 4.5% of eyes had chemosis affecting 2 or more quadrants of the eye. Other adverse events included 14 cases of cyst/granuloma formation in the area of sub-Tenon’s incision and 7 eyes required suturing of the conjunctival cut. Of all patients, 93.2% experienced no or only mild discomfort during or after surgical procedure.

Conclusion

Sub-Tenon’s anesthesia with the use of a flexible cannula is a safe option for ophthalmic anesthesia. No sight-threatening adverse events occurred.

Perioperative considerations and anesthesia management in patients with obstructive sleep apnea undergoing ophthalmic surgery

Obstructive sleep apnea (OSA) is a disorder characterized by breathing cessation caused by obstruction of the upper airway during sleep. It is associated with multiorgan comorbidities such as obesity, hypertension, heart failure, arrhythmias, diabetes mellitus, and stroke. Patients with OSA have an increased prevalence of ophthalmic disorders such as cataract, glaucoma, central serous retinopathy (detachment of retina, macular hole), eyelid laxity, keratoconus, and nonarteritic anterior ischemic optic neuropathy; and some might require surgery. Given that OSA is associated with a high incidence of perioperative complications and more than 80% of surgical patients with OSA are unrecognized, all surgical patients should be screened for OSA (eg, STOP-Bang questionnaire) with comorbidities identified. Patients suspected or diagnosed with OSA scheduled for ophthalmic surgery should have their comorbid conditions optimized. This article includes a review of the literature and highlights best perioperative anesthesia practices in the management of ophthalmic surgical patients with OSA.

Preventing Adverse Events in Cataract Surgery: Recommendations From a Massachusetts Expert Panel

Massachusetts health care facilities reported a series of cataract surgery-related adverse events (AEs) to the state in recent years, including 5 globe perforations during eye blocks performed by 1 anesthesiologist in a single day. The Betsy Lehman Center for Patient Safety, a nonregulatory Massachusetts state agency, responded by convening an expert panel of frontline providers, patient safety experts, and patients to recommend strategies for mitigating patient harm during cataract surgery. The purpose of this article is to identify contributing factors to the cataract surgery AEs reported in Massachusetts and present the panel's recommended strategies to prevent them. Data from state-mandated serious reportable event reports were supplemented by online surveys of Massachusetts cataract surgery providers and semistructured interviews with key stakeholders and frontline staff. The panel identified 2 principal categories of contributing factors to the state's cataract surgery-related AEs: systems failures and choice of anesthesia technique. Systems failures included inadequate safety protocols (48.7% of contributing factors), communication challenges (18.4%), insufficient provider training (17.1%), and lack of standardization (15.8%). Choice of anesthesia technique involved the increased relative risk of needle-based eye blocks. The panel's surveys of Massachusetts cataract surgery providers show wide variation in anesthesia practices. While 45.5% of surgeons and 69.6% of facilities reported increased use of topical anesthesia compared to 10 years earlier, needle-based blocks were still used in 47.0% of cataract surgeries performed by surgeon respondents and 40.9% of those performed at respondent facilities. Using a modified Delphi approach, the panel recommended several strategies to prevent AEs during cataract surgery, including performing a distinct time-out with at least 2 care-team members before block administration; implementing standardized, facility-wide safety protocols, including a uniform site-marking policy; strengthening the credentialing and orientation of new, contracted and locum tenens anesthesia staff; ensuring adequate and documented training in block administration for any provider who is new to a facility, including at least 10 supervised blocks before practicing independently; using the least invasive form of anesthesia appropriate to the patient; and finally, adjusting anesthesia practices, including preferred techniques, as evidence-based best practices evolve. Future research should focus on evaluating the impact of these recommendations on patient outcomes.

Ocular delivery of proteins and peptides: Challenges and novel formulation approaches

The impact of proteins and peptides on the treatment of various conditions including ocular diseases over the past few decades has been advanced by substantial breakthroughs in structural biochemistry, genetic engineering, formulation and delivery approaches. Formulation and delivery of proteins and peptides, such as monoclonal antibodies, aptamers, recombinant proteins and peptides to ocular tissues poses significant challenges owing to their large size, poor permeation and susceptibility to degradation. A wide range of advanced drug delivery systems including polymeric controlled release systems, cell-based delivery and nanowafers are being exploited to overcome the challenges of frequent administration to ocular tissues. The next generation systems integrated with new delivery technologies are anticipated to generate improved efficacy and safety through the expansion of the therapeutic target space. This review will highlight recent advances in formulation and delivery strategies of protein and peptide based biopharmaceuticals. We will also describe the current state of proteins and peptides based ocular therapy and future therapeutic opportunities.

Sub-Tenon's anesthesia for canine cataract surgery

OBJECTIVE

To test a sub-Tenon's anesthesia technique in dogs as an alternative to systemic neuromuscular blockade to aid in canine cataract surgery under general anesthesia.

PROCEDURES

A prospective controlled clinical study was performed involving 12 dogs undergoing bilateral cataract surgery under general anesthesia. One eye was randomly assigned to have phacoemulsification and prosthetic lens implantation performed with sub-Tenon's anesthesia (STA), and the control eye had surgery performed with systemic neuromuscular blockade (NMB). Intraocular pressure (IOP) was measured immediately before and after STA administration. Globe position, globe rotation, pupillary dilation, and vitreal expansion were assessed for both STA and NMB eyes during surgery.

RESULTS

Sub-Tenon's anesthesia produced a globe position suitable for cataract surgery with the degree of vitreal expansion not significantly different to control NMB eyes. STA produced greater anterior globe displacement than NMB in all cases. STA had no significant effect on IOP.

CONCLUSION

Sub-Tenon's anesthesia was an effective alternative to systemic neuromuscular blockade for canine cataract surgery and may be beneficial for surgical exposure in deep orbited breeds.

Sub-Tenon's injection in equine cadaver eyes: MRI visualization of anesthetic fluid distribution and comparison of two different volumes

OBJECTIVE

To compare the localization and distribution of two different anesthetic fluid volumes around equine cadaver eyes to determine an appropriate volume for a single sub-Tenon's injection in horses.

PROCEDURE

A single sub-Tenon's injection of 2% lidocaine was performed in 10 equine cadaver heads (20 eyes) using two different volumes (7 mL on one side and 10 mL on the opposite side). The posterior circular distribution of the anesthetic was quantified in sagittal, dorsal, and transverse MRI (T2W-TSE) sequences and evaluated independently by three board-certified radiologists. The distribution of the two fluid volumes was compared via a paired Student's t-test. The interobserver reliability was evaluated via a Kruskal-Wallis test.

RESULTS

Extension of the injection fluid was observed along the dorsal and temporal quadrants of the globe within the subconjunctival space, the anterior and posterior sub-Tenon's space, and into the muscle sheaths along the extraocular muscles. Accumulation of anesthetic fluid directly surrounding the optic nerve was detected in three of 20 cadaver eyes. Circular distribution of the 7 and 10 mL anesthetic volumes was not significantly different (P = 0.849). More retrograde leakage of the anesthetic was observed using the 10 mL volume. Evaluation of interobserver reliability revealed no significant differences between observers (P = 0.21-0.92).

CONCLUSIONS

Sub-Tenon's anesthesia can have potential as an alternative to retrobulbar anesthesia for ophthalmic surgeries in equines. A 7- to 10-mL injection volume should be appropriate based on the results of this study. The distribution of the anesthetic solution in live tissues, the clinical effects, and the potential for complications will have to be evaluated in vivo.

Comparison of Olive Tipped and Conventional Steven's Cannula for Sub-Tenon Ophthalmic Anesthesia

PURPOSE:

To compare the efficacy of the olive tipped (OT) cannula to the conventional Steven's cannula for sub-Tenon block (STB) before cataract surgery.

METHODS:

This prospective, randomized, double-masked compared STB delivered in cataract surgery patients with an OT cannula or a conventional Steven's cannula (ST). Outcome variables included the akinesia score and lid movement scores at 5 and 10 min. The patient perception of pain during delivery of the STB and surgery were also compared between groups. Surgeon satisfaction with anesthesia was compared between groups. P <0.05 was statistically significant.

RESULTS:

There were sixty patients in each group. The age between groups was not statistically different (P = 0.4). The body mass index was higher in the ST group compared to the OT group (P < 0.001). The akinesia score at 5 and 10 min did not differ between groups (P = 0.07 and P = 0.6, respectively). The patient perception of pain during STB and surgery were similar between groups (P = 0.1 and P = 0.06, respectively). There were six patients with mild chemosis and redness in the OT group and 15 patients in the ST group.

CONCLUSION:

An OT cannula is equally effective as the conventional Steven's cannula for delivering STB anesthesia before cataract surgery.

Non-arteritic Anterior Ischaemic Optic Neuropathy after Uneventful Cataract Extraction

We present the case of a 74-year-old Caucasian female who suffered sudden visual loss after routine phacoemulsification cataract surgery. The patient was subsequently diagnosed with non-arteritic anterior ischaemic optic neuropathy. The case is described in detail, and a concise review of the literature is presented together with the authors' view on the subject outlined. This is a very rare complication after cataract surgery even in high-risk patients with associated systemic co-morbidities. We suspect that the previous history of obesity, coronary artery disease, and arteriosclerosis contributed to the development of this serious ocular complication. We suggest appropriate measures to reduce the risk of its occurrence.