Sub-Tenon's anaesthesia versus topical anaesthesia for cataract surgery

Phacoemulsification Techniques and Their Effects on Corneal Endothelial Cells and Visual Acuity: A Review of "Direct-Chop" and "Stop-and-Chop" Approaches Under Topical Anesthesia

Phacoemulsification is a widely adopted technique in cataract surgery that offers a minimally invasive approach to lens removal and intraocular lens implantation. Among the various methods of phacoemulsification, "direct-chop" and "stop-and-chop" techniques are particularly notable for their efficiency and safety profiles. This review aims to evaluate the effects of these two techniques on corneal endothelial cells and visual acuity, specifically under topical anesthesia. Cataract surgery outcomes hinge on the preservation of corneal endothelial cells and the achievement of optimal visual acuity. Endothelial cell loss can lead to corneal decompensation, while visual acuity is a primary measure of surgical success. The "direct-chop" technique involves the immediate chopping of the lens nucleus after groove creation, reducing phacoemulsification time and energy. Conversely, the "stop-and-chop" technique incorporates a central groove before chopping, offering increased control and safety. This review synthesizes current research and clinical studies to compare these techniques, focusing on their respective impacts on endothelial cell count and postoperative visual acuity. It examines the advantages and disadvantages of each approach, considers the role of surgeon experience, phacoemulsification energy, and anterior chamber stability, and assesses patient outcomes under topical anesthesia. The findings aim to provide insights that can guide surgeons in selecting the most appropriate technique for their patients, ultimately enhancing surgical outcomes by ensuring the preservation of corneal health and the achievement of superior visual acuity.

Cataract Surgery-Indications, Techniques, and Intraocular Lens Selection

BACKGROUND

Opacification of the lens of the eye (cataract) is usually due to aging. It is a painless, progressive condition that affects contrast and color perception and alters refraction, leading to visual loss that may be total. In cataract surgery, the turbid lens is replaced by an artificial lens. An estimated 600 000 to 800 000 such procedures are performed in Germany each year.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed, including meta-analyses, Cochrane reviews, and randomized controlled clinical trials (RCTs).

RESULTS

Cataract is the most common reversible cause of blindness around the world (approximately 95 million people). The surgical replacement of a turbid lens with an artificial lens is usually carried out under local anesthesia. The standard technique for fragmentation of the nucleus of the lens is ultrasonic phacoemulsification. RCTs have not shown the superiority of the femtosecond laser over phacoemulsification for this purpose so far. The spectrum of artificial intraocular lenses, aside from the conventional type with a single focus, include lenses with multiple foci, extended-depth-of-focus (EDOF) lenses, and astigmatism-correcting lenses.

CONCLUSION

In Germany, cataract surgery is usually performed on an outpatient basis under local anesthesia. Artificial lenses with various additional functions are available nowadays; the choice of lens depends on the needs of the individual patient. Patients must be adequately informed about the advantages and disadvantages of the different lens systems.

Using Alprazolam before phacoemulsification cataract surgery reduces complications and duration of the surgery

PURPOSE

To evaluate the effect of preoperative Alprazolam on complications of phacoemulsification cataract surgery, duration of surgery and early reoperation rate.

METHODS

Records of 1026 eyes of 1026 consecutive patients underwent phacoemulsification with topical and intracameral anesthesia between 2016 and 2020 years were retrospectively reviewed. Patients were divided into two groups, with or without using Alprazolam before surgery. Patients with planned first-time surgery for senile cataract and at least three months follow-up postoperatively were included. Those who had pseudoexfoliation, small pupil, zonular weakness, corneal and hearing problem as well as traumatic, brown, mature, hypermature, and posterior polar cataracts were excluded. Main outcome measures were duration of surgery, posterior capsule rupture, rapid posterior capsule opacification (PCO) formation requiring the neodymium: yttrium-aluminum-garnet (Nd:YAG) laser and reoperation rate in early postoperative periods.

RESULTS

Alprazolam and control groups included 490 and 536 eyes, respectively. Mean surgical time was shorter in Alprazolam group (10.2 ± 3 versus 12.2 ± 4 min; < 0.001). Rate of posterior capsule rupture was higher in control group (4 versus 15 eyes; = 0.02). Four eyes (0.8%) in control group underwent unplanned secondary surgical procedures in early postoperative period (P = 0.126). Rate of rapid PCO formation was higher in control group (1 versus 9 eyes; = 0.027).

CONCLUSIONS

Using Alprazolam before phacoemulsification can lead to less posterior capsule rupture, short operation time and prevent repetitive surgery. It also reduces rapid PCO formation and, thus, early Nd:YAG laser intervention due to better cleaning the posterior capsule during surgery. We conclude that Alprazolam not only reduces intraoperative complications, but also facilitates their management.

The Effect of Binaural Beat Audio on Operative Pain and Anxiety in Cataract Surgery under Topical Anaesthesia: A Randomized Controlled Trial

Background: The aim of this paper was to examine the analgesic and anxiolytic effects of binaural beat audio in patients undergoing cataract surgery under topical anaesthesia. Methods: This was a prospective, randomized controlled trial of 61 patients undergoing cataract surgery under topical anaesthesia. They were divided into two research conditions; the binaural beat audio group, and a sham-control group (ear phones with no music). Patients completed the State-Trait Anxiety Inventory questionnaire (STAI), and their blood pressure (BP) and heart rate (HR) were measured pre- and post-intervention. Intraoperative pain levels were ascertained using a visual analog scale (VAS) completed immediately after the surgery. Results: The binaural beat group had significantly lower pain scores (p < 0.001), HR (p < 0.001), diastolic BP (p = 0.003), mean arterial pressure (p = 0.007) and anxiety (p = 0.009) than the control group. Within the binaural beat group, subjects experienced a statistically significant reduction in HR (p = 0.004) and anxiety (p < 0.001) levels compared to baseline values, while all parameters, except anxiety, increased significantly in the control group. Conclusions: Binaural beat audio decreases operative pain and anxiety in cataract surgery under topical anaesthesia. It may have additional benefits in modulating the tachycardic response to stress.

CONTEMPORARY PRACTICES IN CATARACT SURGERY - SUBJECTIVE PREFERENCES OF CZECH CATARACT SURGEONS

AIMS

The aim of the work was to find out the current subjective preferences of Czech cataract surgeons in terms of individual procedures, techniques and materials used during cataract surgery.

MATERIAL AND METHODS

This study was conducted in the form of a questionnaire (online, a total of 44 questions). The survey respondents were members of the Czech Society of Refractive and Cataract Surgery. Questions 1-10 concerned the characteristics of the respondent (age, number of operations performed, type of workplace, etc.). Questions 11-20 focused on the surgical procedure used by the specific surgeon (anaesthesia, viscomaterial, position of the main incision, use of antibiotics at the end of the operation, etc.). Questions 21-34 concerned the type of intraocular lens used. Lastly, in questions 35-44, respondents were asked about their individual preferences if cataract surgery were to be performed on them.

RESULTS

The questionnaire was fully or partially completed by 72 surgeons (26% of the originally approached subjects). Most of the respondents were experienced surgeons, 74.5% of them have been performing surgeries for more than 10 years, out of which 55.5% perform more than 500 operations per year. The average age of the respondents was 50 years. 65.3% of surgeons use hydroxypropylmethylcellulose during surgery, 74% do not use a femtosecond laser for surgery, 50% never perform posterior circular capsulorhexia, and 98% apply antibiotics to the anterior chamber at the end of surgery. Surgeons predominantly use hydrophobic (80.8%), aspherical (72.3%), clear (54.3%), single-focal (97.9%) and non-preloaded (78.3%) lenses. However, if they were not limited or restricted in any way in their choice, they would prefer aspherical lenses (94.6%), multifocal or extended-focus lenses (78%) and preloaded lenses (96.8%).

CONCLUSION

The subjective preferences of Czech cataract surgeons are relatively variable regarding the individual steps. Often the procedures used do not always correspond with the actual preferences of the surgeon. On the contrary, there is almost complete unity in the steps recommended by professional societies (intracameral antibiotics at the end of the operation).

Anterior Subconjunctival Anesthesia for Manual Small Incision Cataract Surgery: A Randomized Controlled Trial

Purpose:

To compare the effectiveness of anterior subconjunctival anesthesia (ASCA) with sub-tenon's anesthesia (STA) for manual small incision cataract surgery (MSICS), regarding pain, akinesia, surgeon comfort, and complications.

Methods:

This trial randomized 164 patients into two groups. Group 1 received ASCA, and Group 2 received STA. MSICS was performed on all patients. Any complications of anesthesia were noted before starting surgery. Patient ocular motility during surgery was scored between 0 and 4 based on the number of directions of gaze in which movement persisted. Following surgery, patients scored pain felt during surgery on a visual pain-score analog, and the surgeon graded for “discomfort” felt during surgery from 0 (Nil) to 4 (additional anesthesia needed).

Results:

Chemosis due to anesthesia and persistence of ocular motility in all four gaze directions were seen in all 82 patients of Group 1, but these did not prevent the surgeon from performing MSICS. Seventy-seven patients (94%) in Group 1 and 79 (96.4%) in Group 2 had no or mild pain during surgery. The surgeon had moderate-to-severe discomfort in 14 (17.2%) Group 1 patients and 3 (3.6%) Group 2 patients, most of whom had deep-set eyes or exhibited excessive eye movements. Two patients in Group 1 and one patient in Group 2 were converted to peribulbar block.

Conclusion:

ASCA is a safe and effective alternative for performing MSICS. It does not induce akinesia but provides adequate anesthesia for the surgery in most patients, except those with deep-set eyes, especially if displaying increased anxiety.

Patient preference and pain-reported outcomes for topical versus subtenon anesthetic for cataract surgery

PURPOSE:

Cataract extraction and lens implantation is the most common surgical procedure performed worldwide, with surgeons opting for either a topical or a subtenon anesthetic in majority of cases. While complication rates and pain scores have been previously examined in a bid to determine which modality was better, patients who have had both eyes operated upon under different techniques have never previously been asked which method they prefer. We undertook this study to fill in this crucial gap in our knowledge.

METHODS:

This is a retrospective study of patients who have undergone bilateral cataract surgery with one eye operated on with topical anesthesia and the other eye with subtenon anesthesia. Patients were identified who had had surgery undertaken in the previous 6 months at Singleton Hospital, Swansea, where both eyes had been operated upon using different anesthetic techniques. Telephone interviews with these patients were performed and their pain scores recorded on a scale from 0 (no pain) to 10 (severe pain) for both eyes, with the patients then being asked which the method of anesthetic they preferred. Statistical analysis of pain scores was compared using Wilcoxon rank-sum testing.

RESULTS:

One hundred and fifty-two patients in total were identified. One hundred and forty-one of the applicable patients participated in the study. Of these, 78 patients received topical anesthesia for their first operation and 63 had subtenon block for their first operation. The mean pain scores reported for surgery with topical anesthesia and subtenon block were 2.30 and 1.38, respectively. The pain data were analyzed using a Wilcoxon signed-rank test, returning a z-score of 4.038. This result therefore suggests that patients experience statistically significantly less pain from cataract surgery when given a subtenon block. Patients expressed a preference for subtenon anesthesia, with 70% preferring subtenon block, 23% preferring topical anesthesia, and 7% having no preference.

CONCLUSIONS:

Patients report less pain with subtenon anesthesia compared with topical anesthesia in cataract surgery, where both eyes were operated upon with different anesthetic techniques. This is the first study in which patients who have had both anesthetic techniques performed independently for cataract surgery have had their pain scores reported and statistically analyzed.

Five Pearls for Long Eyes

Collapse

Topical anaesthesia plus intracameral lidocaine versus topical anaesthesia alone for phacoemulsification cataract surgery in adults

BACKGROUND

Phacoemulsification cataract surgery is usually performed in adults under local anaesthesia. Topical anaesthesia, which involves instilling anaesthetic drops to the ocular surface prior to and during surgery, has found large acceptance internationally. It is safe and allows for rapid patient turnover and visual recovery. Some surgeons have supplemented topical anaesthesia with intracameral lidocaine, reasoning that this may further reduce intraoperative pain, particularly during surgical stages involving manipulation of intraocular structures and rapid changes in fluid dynamics. This review, originally published in 2006 and updated in 2020, explores the efficacy and safety of using supplementary intracameral lidocaine in phacoemulsification cataract surgery.

OBJECTIVES

To assess whether supplementing topical anaesthesia with intracameral lidocaine for phacoemulsification cataract surgery in adults reduces intraoperative and postoperative pain, and to assess differences in participant satisfaction, need for additional intraoperative anaesthesia, surgeon satisfaction, measures of intraocular toxicity, and adverse effects attributable to choice of anaesthesia.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS BIREME iAH, and six trial registries on 4 February 2020. We also searched the reference lists of identified studies. There were no language restrictions.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) where participants underwent phacoemulsification for age-related cataract under topical anaesthesia with or without intracameral lidocaine either in two eyes of the same participant, or in different participants. We also included studies that used oral or intravenous sedation in addition to local anaesthesia.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial methodological quality using standard Cochrane procedures.

MAIN RESULTS

We identified five new RCTs in this updated review. We included a total of 13 trials in the review, conducted in the UK, the USA, Australia, Italy, Canada, Taiwan, Singapore, India, and Pakistan, and comprising 2388 eyes of 2355 participants (one study was a paired-eye study with each participant acting as their own control). The age range of participants was 34 to 95 years. We excluded studies that only included low-risk participants and excluded more difficult operative cases, for example hard lens nuclei or small pupils. We excluded studies assessing only participants with Fuchs' endothelial dystrophy. We judged one study as at high risk for selection bias. We assessed five studies as having an unclear risk of bias for random sequence generation and seven studies an unclear risk of bias for allocation concealment. We judged three studies as at high risk of performance bias, as the surgeon was not blinded, and two studies as at unclear risk of bias for this domain. No studies were judged as at high risk for detection bias, but five studies were judged to have an unclear risk of bias for this domain. We judged all 13 included studies to have a low risk of attrition bias and an unclear risk of reporting bias. Data from eight RCTs favoured topical anaesthesia plus intracameral lidocaine 0.5% to 1% over topical anaesthesia alone for reducing intraoperative pain when measured using a 10-point visual analogue scale, analysed as a continuous outcome. Mean pain score was 0.26 lower in the supplemental intracameral lidocaine group (95% confidence interval (CI) -0.39 to -0.13, 1692 eyes, moderate-quality evidence). Data from seven RCTs favoured supplemental intracameral lidocaine for reducing intraoperative pain when measured as a dichotomous outcome. The odds ratio of experiencing any pain was 0.40 versus the topical anaesthesia-only group (95% CI 0.29 to 0.57, 1268 eyes, moderate-quality evidence). Data from four RCTs did not show any additional benefit on postoperative pain when measured using a 10-point visual analogue scale (mean difference 0.12 points, 95% CI -0.29 to 0.05, 751 eyes, moderate-quality evidence). The impact on participant satisfaction was uncertain as only one small study investigated this outcome. The study suggested no difference between groups (mean difference 0.1 points, 95% CI -0.47 to 0.27, 60 eyes, low-quality evidence). Data from seven RCTs did not demonstrate a difference between groups in the need for additional intraoperative anaesthesia (odds ratio 0.88, 95% CI 0.56 to 1.39, 1194 eyes of 1161 participants; low-quality evidence), although this result is uncertain. A variety of measures were reported relating to possible intraocular toxicity. Data from four RCTs did not demonstrate a difference between groups in mean percentage corneal endothelial cell count change from pre- to postoperatively (mean difference 0.89%, 95% CI -1.12% to 2.9%, 254 eyes of 221 participants, moderate-quality evidence). Synthesis of the evidence from eight RCTs identified no difference in intraoperative adverse events between groups (odds ratio 1.00, 95% CI 0.32 to 3.16, 1726 eyes, low-quality evidence). This result should be interpreted with caution, mainly due to a lack of clear definitions of adverse events, low numbers of events, heterogeneity between studies, and large confidence intervals. Large observational studies may have been more appropriate for looking at this outcome.

AUTHORS' CONCLUSIONS

There is moderate-quality evidence that supplementation of topical anaesthesia with intracameral lidocaine 0.5% to 1% for phacoemulsification cataract surgery in adults reduces participant perception of intraoperative pain. The odds of experiencing any pain (as opposed to no pain) were 60% less for the topical anaesthesia plus intracameral lidocaine group versus the topical anaesthesia-only group. However, the numerical amplitude of the effect may not be of great clinical significance on the continuous pain score scale. Generally, the pain scores were consistently low for both techniques. We found moderate-quality evidence that there is no additional benefit of intracameral lidocaine on postoperative pain. There is insufficient evidence to determine the impact on participant satisfaction and need for additional intraoperative anaesthesia due to low-quality evidence. There is moderate-quality evidence that intracameral lidocaine supplementation does not increase measures of intraocular toxicity, specifically loss of corneal endothelial cells. There is low-quality evidence that the incidence of intraoperative adverse events is unchanged with intracameral lidocaine supplementation, but as RCTs are not the optimum medium for looking at this, this result should be interpreted with caution. Further research specifically investigating the adverse effects of intracameral anaesthesia might help to better determine its safety profile. Economic evaluations would also be useful for detailing cost implications.

Identification and Description of Reliable Evidence for 2016 American Academy of Ophthalmology Preferred Practice Pattern Guidelines for Cataract in the Adult Eye

Importance

Trustworthy clinical practice guidelines require reliable systematic reviews of the evidence to support recommendations. Since 2016, the American Academy of Ophthalmology (AAO) has partnered with Cochrane Eyes and Vision US Satellite to update their guidelines, the Preferred Practice Patterns (PPP).

Objective

To describe experiences and findings related to identifying reliable systematic reviews that support topics likely to be addressed in the 2016 update of the 2011 AAO PPP guidelines on cataract in the adult eye.

Design, Setting, and Participants

Cross-sectional study. Systematic reviews on the management of cataract were searched for in an established database. Each relevant systematic review was mapped to 1 or more of the 24 management categories listed under the Management section of the table of contents of the 2011 AAO PPP guidelines. Data were extracted to determine the reliability of each systematic review using prespecified criteria, and the reliable systematic reviews were examined to find whether they were referenced in the 2016 AAO PPP guidelines. For comparison, we assessed whether the reliable systematic reviews published before February 2010 the last search date of the 2011 AAO PPP guidelines were referenced in the 2011 AAO PPP guidelines. Cochrane Eyes and Vision US Satellite did not provide systematic reviews to the AAO during the development of the 2011 AAO PPP guidelines.

Main Outcomes and Measures

Systematic review reliability was defined by reporting eligibility criteria, performing a comprehensive literature search, assessing methodologic quality of included studies, using appropriate methods for meta-analysis, and basing conclusions on review findings.

Results

From 99 systematic reviews on management of cataract, 46 (46%) were classified as reliable. No evidence that a comprehensive search had been conducted was the most common reason a review was classified as unreliable. All 46 reliable systematic reviews were cited in the 2016 AAO PPP guidelines, and 8 of 15 available reliable reviews (53%) were cited in the 2011 PPP guidelines.

Conclusions and Relevance

The partnership between Cochrane Eyes and Vision US Satellite and the AAO provides the AAO access to an evidence base of relevant and reliable systematic reviews, thereby supporting robust and efficient clinical practice guidelines development to improve the quality of eye care.

Routine preoperative medical testing for cataract surgery

BACKGROUND

Cataract surgery is practiced widely, and substantial resources are committed to an increasing cataract surgical rate in low- and middle-income countries. With the current volume of cataract surgery and future increases, it is critical to optimize the safety and cost-effectiveness of this procedure. Most cataracts are performed on older individuals with correspondingly high systemic and ocular comorbidities. It is likely that routine preoperative medical testing will detect medical conditions, but it is questionable whether these conditions should preclude individuals from cataract surgery or change their perioperative management.

OBJECTIVES

1. To investigate the evidence for reductions in adverse events through preoperative medical testing2. To estimate the average cost of performing routine medical testing SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2018, Issue 6); Ovid MEDLINE; Embase.com; PubMed; LILACS BIREME, the metaRegister of Controlled Trials (mRCT) (last searched 5 January 2012); ClinicalTrials.gov and the WHO ICTRP. The date of the search was 29 June 2018, with the exception of mRCT which is no longer in service. We searched the references of reports from included studies for additional relevant studies without restrictions regarding language or date of publication.

SELECTION CRITERIA

We included randomized clinical trials in which routine preoperative medical testing was compared to no preoperative or selective preoperative testing prior to age-related cataract surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed abstracts to identify possible trials for inclusion. For each included study, two review authors independently documented study characteristics, extracted data, and assessed risk of bias.

MAIN RESULTS

We identified three randomized clinical trials that compared routine preoperative medical testing versus selective or no preoperative testing for 21,531 cataract surgeries. The largest trial, in which 19,557 surgeries were randomized, was conducted in Canada and the USA. Another study was conducted in Brazil and the third in Italy. Although the studies had some issues with respect to performance and detection bias due to lack of masking (high risk for one study, unclear for two studies), we assessed the studies as at overall low risk of bias.The three randomized clinical trials included in this review reported results for 21,531 total cataract surgeries with 707 total surgery-associated medical adverse events, including 61 hospitalizations and three deaths. Of the 707 medical adverse events reported, 353 occurred in the pre-testing group and 354 occurred in the no-testing group (odds ratio (OR) 1.00, 95% confidence interval (CI) 0.86 to 1.16; high-certainty evidence). Most events were cardiovascular and occurred during the intraoperative period. Routine preoperative medical testing did not reduce the risk of intraoperative (OR 0.99, 95% CI 0.71 to 1.38) or postoperative ocular adverse events (OR 1.11, 95% CI 0.74 to 1.67) when compared to selective or no testing (2 studies; 2281 cataract surgeries; moderate-certainty evidence). One study evaluated cost savings, estimating the costs to be 2.55 times higher in those with preoperative medical testing compared to those without preoperative medical testing (1 study; 1005 cataract surgeries; moderate-certainty evidence). There was no difference in cancellation of surgery between those with preoperative medical testing and those with selective or no preoperative testing, reported by two studies with 20,582 cataract surgeries (OR 0.97, 95% CI 0.78 to 1.21; high-certainty evidence). No study reported outcomes related to clinical management changes (other than cancellation) or quality of life scores.

AUTHORS' CONCLUSIONS

This review has shown that routine preoperative testing does not increase the safety of cataract surgery. Alternatives to routine preoperative medical testing have been proposed, including self administered health questionnaires, which could substitute for health provider histories and physical examinations. Such avenues may lead to cost-effective means of identifying those at increased risk of medical adverse events due to cataract surgery. However, despite the rare occurrence, adverse medical events precipitated by cataract surgery remain a concern because of the large number of elderly patients with multiple medical comorbidities who have cataract surgery in various settings. The studies summarized in this review should assist recommendations for the standard of care of cataract surgery, at least in low- and middle-income settings. Unfortunately, in these settings, medical history questionnaires may be useless to screen for risk because few people have ever been to a physician, let alone been diagnosed with any chronic disease.

Use of hyaluronidase as an adjunct to local anaesthetic eye blocks to reduce intraoperative pain in adults

BACKGROUND

Hyaluronidase has been used over many decades as an adjunct to local anaesthetic solution to improve the speed of onset of eye blocks and to provide better akinesia and analgesia. With the evolution of modern eye surgery techniques, fast onset and akinesia are not essential requirements anymore. The assumption that the addition of hyaluronidase to local anaesthetic injections confers better analgesia for the patient needs to be examined. There has been no recent systematic review to provide evidence that hyaluronidase actually improves analgesia.

OBJECTIVES

To ascertain if adding hyaluronidase to local anaesthetic solutions for use in ophthalmic anaesthesia in adults results in a reduction of perceived pain during the operation and to assess harms, participant and surgical satisfaction, and economic impact.

SEARCH METHODS

We carried out systematic searches in Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and four other databases in June 2017. We searched the trial registers at www.ISRCTN.com, ClinicalTrials.gov and www.clinicaltrialsregister.eu for relevant trials. We imposed no language restrictions.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that evaluated the effect of hyaluronidase on pain experienced by adults during intraocular surgery using a rating scale.

DATA COLLECTION AND ANALYSIS

Two review authors (HR and KA) independently extracted data and assessed methodological quality using standard procedures as expected by Cochrane.

MAIN RESULTS

We included seven trials involving 500 participants that studied the effect of hyaluronidase on intraoperative pain. Four of the seven trials with 289 participants reported the primary outcome in a dichotomous manner, and we proceeded to meta-analyse the findings which showed a moderate heterogeneity that could not be explained (I2 = 41% ). The pooled risk ratio (RR) for these four trials was 0.83 with the 95% confidence interval ranging from 0.48 to 1.42. The reduction in intraoperative pain scores in the hyaluronidase group were not statistically significant. Among the three trials that reported the primary outcome in a continuous manner, the presence of missing data made it difficult to conduct a meta-analysis. To further explore the data, we imputed standard deviations for the other studies from another included RCT (Sedghipour 2012). However, this resulted in substantial heterogeneity between study estimates (I² = 76% ). The lack of reported relevant data in two of the three remaining trials made it difficult to assess the direction of effect in a clinical setting.Overall, there was no statistical difference regarding the intraoperative reduction of pain scores between the hyaluronidase and control group. All seven included trials had a low risk of bias.According to GRADE, we found the quality of evidence was low and downgraded the trials for serious risk of inconsistency and imprecision. Therefore, the results should be analysed with caution.Participant satisfaction scores were significantly higher in the hyaluronidase group in two high quality trials with 122 participants. Surgical satisfaction was also superior in two of three high quality trials involving 141 participants. According to GRADE, the quality of evidence was moderate for participant and surgical satisfaction as the trials were downgraded for imprecision due to the small sample sizes. The risk of bias in these trials was low.There was no reported harm due to the addition of hyaluronidase in any of the studies. No study reported on the cost of hyaluronidase in the context of eye surgery.

AUTHORS' CONCLUSIONS

The effects of adding hyaluronidase to local anaesthetic fluid on pain outcomes in people undergoing eye surgery are uncertain due to the low quality of evidence available. A well designed RCT is required to address inconsistency and imprecision among the studies and to determine the benefit of hyaluronidase to improve analgesia during eye surgery. Participant and surgical satisfaction is higher with hyaluronidase compared to the control groups, as demonstrated in moderate quality studies. There was no harm attributed to the use of hyaluronidase in any of the studies. Considering that harm was only rarely defined as an outcome measure, and the overall small number of participants, conclusions cannot be drawn about the incidence of harmful effects of hyaluronidase. None of the studies undertook cost calculations with regards to use of hyaluronidase in local anaesthetic eye blocks.

Intraoperative head drift and eye movement: two under addressed challenges during cataract surgery

PURPOSE

To objectively measure head drift during cataract surgery, and subjectively simulate eye movements and assess impact on surgical technique.

MATERIALS AND METHODS

Twelve consecutively recorded routine cataract operations in the Tennent Institute of Ophthalmology, Gartnavel General Hospital, Glasgow, were reviewed. The speculum was used as a fixed point and correlated with a superimposed virtual ruler to measure maximum head drift in each direction throughout the operations. To simulate intraoperative eye movement, we attached string to the cataract surgical simulator (Eyesi) eye and manually induced abduction and adduction. A calibrated scale secured to the Eyesi head ensured 5 mm eye movements were consistently created. Ophthalmology trainees performed the continuous curvilinear capsulorhexis (CCC) exercise without and with sequential eye movements. Movements were induced every three seconds. Scores were compared using a paired Student's T-test.

RESULTS

Mean head drift in the surgical recordings was 3.1 mm medially (range 2-7 mm), 2.9 mm laterally (range 2-4 mm), 2.6 mm superiorly (range 1-5 mm), and 1.9 mm inferiorly (range 1-4 mm). In 11 of 12 cases, the operating microscope had to be adjusted for head drift. Six junior trainees completed the CCC module on the Eyesi without then with eye movements. After introducing eye movements the mean Eyesi score reduced from 92.7 to 76.9 (P = 0.014), 'roundness of rhexis' score reduced from 89.4 to 57.5 (P = 0.020), and trainees operated 17 s faster (P = 0.016).

CONCLUSION

This study objectively demonstrates the under-reported clinical scenario of head drift during cataract surgery. By manipulating the Eyesi we have shown that eye movements reduce the quality of cataract surgery.