Anesthetic effectiveness of topical levobupivacaine 0.75% versus topical proparacaine 0.5% for intravitreal injections

Pain perception during intravitreal injections is related to the timing of instilling anesthetic eyedrops

PURPOSE

To evaluate the correlation between the timing of instilling anesthetic eyedrops prior to intravitreal injection and the patient's perception of pain associated with the injection.

METHODS

A prospective observational study which included 192 eyes of 192 patients. Time interval between instillation of Oxybuprocaine-0.4% and Tetracaine-0.5% eyedrops upon checking-in and injection was measured and pain level was evaluated by the 101-point-Numeric Rating Scale.

RESULTS

We found significant correlation between time interval from the first eyedrops to injection and injection related pain. The lowest pain score (11 ± 18) was found in the 11-15 min group, while the highest was found in the 0-6 min (26 ± 25) and in the > 35 min (31 ± 28) groups. The highest percentage of patients without pain was found in the 11-15 min (64%), followed by the 7-10 min (56%) and 16-20 min (47%) groups. 10% or 17% of the 0-6 min or > 35 min. groups, respectively, reported no pain. No patients in 11-15 min group reported severe pain versus 10% in the 0-6 min and 17% in the > 35 min groups. The highest percentage of patients with 'absent-to-mild' pain was in the 11-15 min (89%) and the 7-10 min (87%) compared to all other groups.

CONCLUSIONS

Administration of first dose of anesthetic eyedrops within 11-15 min before intravitreal injection yields the lowest levels of injection-related pain, with 7-10 min being second best. Administration of eyedrops outside of this time-window results in higher pain levels avoidable with more attention to the timing issue.

Cooling Anesthesia for Intravitreal Injections - A Review

Intravitreal (IVT) injections are the most common procedure performed in retinal clinics today. It has revolutionized the treatment of neovascular age-related macular degeneration (nAMD), diabetic macular edema, macular edema due to veinous occlusive disease and other forms of exudative maculopathy. Though IVT injections prevent vision loss, the discomfort at the time of the injection has been troublesome to patients. This has led to patients missing their regular and routine dosage of treatment. Various modes of pre-injection anesthetic methods have been tried but in vain. Lidocaine-based topical anesthesia, in the form of pledgets, topical gel or subconjunctival lidocaine injection, has been the standard of care (SOC) for IVT injections worldwide. This article highlights the role of cooling anesthesia in reducing pain, anxiety and discomfort associated with needle penetration at the time of injection. PubMed and MedLine search were related to anesthesia for intravitreal injections, cooling anesthesia, mechanism of cooling anesthesia, COOL-1 trial, COOL-2 trial, results of COOL-1 trial and ultrarapid cooling anesthesia.

Critical analysis of techniques and materials used in devices, syringes, and needles used for intravitreal injections

Intravitreal injections have become the most commonly performed intraocular treatments worldwide. Because intravitreal injections may induce severe adverse events, such as infectious and noninfectious endophthalmitis, cataract, ocular hypertension, vitreous hemorrhage, or retinal detachment, appropriate awareness of the materials and techniques used are essential to reduce these sight-threatening complications. This review provides insights into the needles, syringes, silicone oil coating, sterilization methods, devices to assist intravitreal injections, scleral piercing techniques using needles, syringe handling, anesthesia, and safety issues related to materials and techniques. It is paramount that physicians be aware of every step involved in intravitreal injections and consider the roles and implications of all materials and techniques used. The ability to understand the theoretical and practical circumstances may definitely lead to state-of-the-art treatments delivered to patients. The most important practical recommendations are: choosing syringes with as little silicone oil as possible, or, preferably, none; avoiding agitation of syringes; awareness that most biologics (e.g., antiangiogenic proteins) are susceptible to changes in molecular properties under some conditions, such as agitation and temperature variation; understanding that improper materials and techniques may lead to complications after intravitreal injections, e.g., inflammation; and recognizing that some devices may contribute to an enhanced, safer, and faster intravitreal injection technique.

Anesthesia for Intravitreal Injection: A Systematic Review

Background

The intravitreal injection has become one of the most commonly performed procedures in ophthalmology; however, there is no standardized approach to anesthesia during the procedure. The goal of this systematic review is to review approaches to anesthesia for intravitreal injection and look at comparative efficacy between these different anesthetics.

Methods

A systematic review of literature was performed in the MEDLINE, PubMed, Cochrane Library, and Clinicaltrials.gov databases using the key words “anesthesia”, “pain management”, and “intravitreal injection”. Of the initial 239 search matches, 30 articles were found to be relevant to the topic. 18 studies were excluded as they did not include primary data or did not include the visual analog scale as a primary outcome. The remaining 12 articles were assessed to look at the comparative efficacy of anesthesia and adverse events.

Results

The anesthesia techniques reported include topical methods such as anesthetic eyedrops, anesthetic gels, and anesthetic-soaked pledgets as well as subconjunctival injection of anesthetic. Ultimately, no single anesthetic or delivery mechanism was shown to be superior to the others in a statistically significant way and adverse events were largely insignificant. Limitations of these studies include relatively small sizes of the studies, as well as the lack of masking which may introduce bias.

Conclusion

In the current literature, no type of anesthetic method was found to be superior to another for intravitreal injection. Future studies in this area may lead to new insights into the efficacy of different forms of intravitreal anesthesia.

Factors Associated with Pain Following Intravitreal Injections

Purpose

To investigate factors associated with pain intensity following intravitreal injection and factors that might be associated with changes in pain intensity in patients who received repeated injections.

Methods

A total of 172 eyes (147 patients) were prospectively enrolled. Patients rated their pain from 0 to 10 using a visual analogue scale. Multiple linear regression analysis was used to evaluate factors associated with pain score. Sixty-eight patients evaluated their degree of pain more than once and were divided into three groups according to changes in pain during repeated injections. Clinical factors were compared among the three groups.

Results

Pain scores of women (women, 3.1 ± 1.5 vs. men, 2.4 ± 1.2; p = 0.003), those who received dexamethasone implant injection (dexamethasone implant, 3.5 ± 1.1 vs. anti-vascular endothelial growth factor, 2.7 ± 1.4; p = 0.028), and those who did not undergo anterior chamber paracentesis (ACP) (ACP, 2.6 ± 1.3 vs. no ACP, 3.0 ± 1.6; p = 0.047) were significantly higher than those of the other groups. On multiple linear regression analysis, only female sex and ACP were significantly associated with degree of pain. The waiting time during the second injection was significantly associated with change in degree of pain in patients who received repeated injections.

Conclusions

Women were more prone to perceive pain, and the ACP procedure reduced pain during intravitreal injections. Most patients who received repeated injections felt that pain was similar or decreased compared to that experienced during the previous injection. However, increased waiting time might have been associated with increased discomfort for patients who received repeated injections.

EFFECT OF BROMFENAC ON PAIN RELATED TO INTRAVITREAL INJECTIONS: A Randomized Crossover Study

PURPOSE

To evaluate the analgesic effect of bromfenac, a topically administered nonsteroidal antiinflammatory agent, in patients undergoing intravitreal injections (IVIs) of anti-vascular endothelial growth factor agents.

METHODS

A single center, prospective, randomized, double-blind, placebo-controlled, cross over interventional study. Patients scheduled to undergo IVI of anti-vascular endothelial growth factor were randomized to receive topical bromfenac or placebo before IVI. Pain perception was assessed using the short form of the McGill Pain Questionnaire. Pain intensity was evaluated with the visual analog scale, the main component of the short form of the McGill Pain Questionnaire, and the Present Pain Intensity scores immediately and 6 hours postinjection.

RESULTS

Sixty-five patients (65 eyes) were enrolled in the study. Immediately after IVI, pain perception was statistically significant lower in patients treated with bromfenac compared with placebo as assessed by the visual analog scale pain score and the main component of the short form of the McGill Pain Questionnaire (P = 0.002 and 0.001, respectively). At 6 hours postIVI, pain was statistically significant lower in patients treated with bromfenac, according to the visual analog scale pain score, the main component of the short form of the McGill Pain Questionnaire, and the Present Pain Intensity score (P < 0.001, <0.001, and P = 0.001, respectively). Multivariable regression analysis revealed that pain perception, as evaluated with the visual analog scale pain score immediately after IVI, was significantly lower in patients of older age, female patients and those with higher number of previous injections. Immediately after IVI, bromfenac seemed to be more effective in younger patients and in those who had already undergone an amount of injections.

CONCLUSION

Topical instillation of bromfenac significantly reduced the IVI-related pain immediately after and 6 hours postinjection.

Patient pain during intravitreal injections under topical anesthesia: a systematic review

Background

Intravitreal injection (IVI) is a very common vitreoretinal procedure, and multiple injections are often required per patient. This systematic review was conducted to evaluate the effectiveness of various local anesthetic techniques in reducing pain during injection.

Methods

A systematic review was conducted based on searches of Cochrane, LILACS, PubMed, Scopus, Web of Science, and the gray literature (Google Scholar). The end search date was February 19, 2016, across all databases. We classified pain by converting visual analog scale (VAS) scores (0–100 mm) into Jensen’s classification levels: 0–4, no pain; 5–44, mild pain; 45–74, moderate pain; and 75–100, severe pain. An intervention was considered clinically significant when pain score change was >12 mm on a 100-mm scale.

Results

Eight studies out of 23 met the eligibility criteria. The total number of patients was 847. Most studies (5/8 [62.5%]) were at unclear risk of bias because of unclear randomization, thus providing only moderate evidence to this review. The anesthetic techniques included eye drops with proparacaine, tetracaine or cocaine, a lidocaine pledget or gel, and subconjunctival injection of 2% lidocaine or 0.75% levobupivacaine. No study comprised all of the techniques. Pain was mild (VAS scores, 5–44 mm) regardless of anesthetic technique. A clinically significant intervention (pain score change >12 mm) was found for only one study comparing proparacaine drops, lidocaine gel, and subconjunctival lidocaine; in that study, a subconjunctival injection of 2% lidocaine provided the greatest pain reduction. A meta-analysis was not possible due to study heterogeneity.

Conclusions

Patient pain during IVI under topical anesthesia is mild regardless of anesthetic technique. A subconjunctival injection of 2% lidocaine could be an option for highly sensitive patients. However, with moderate level of evidence, no single anesthetic technique could be defined as the best option for IVI.

Electronic supplementary material

The online version of this article (doi:10.1186/s40942-017-0076-9) contains supplementary material, which is available to authorized users.