Combined indomethacin/gentamicin eyedrops to reduce pain after traumatic corneal abrasion

Topical analgesics for acute corneal pain: current options and emerging therapeutics

Acute corneal pain is a common complaint that causes significant distress to patients and continues to challenge therapeutic avenues for pain management. Current topical treatment options have marked limitations in terms of both efficacy and safety, thus often prompting the adjunctive use of systemic analgesics, including opioids. In general, there have not been extensive advancements in pharmacologic options for the management of corneal pain over the past several decades. Despite this, multiple promising therapeutic avenues exist which hold the potential to transform the ocular pain landscape, including druggable targets within the endocannabinoid system. This review will summarize the current evidence base for topical nonsteroidal anti-inflammatory drugs, anticholinergic agents, and anesthetics before focusing on several potential avenues in the setting of acute corneal pain management, including autologous tear serum, topical opioids and endocannabinoid system modulators.

Antibiotic prophylaxis for corneal abrasion

BACKGROUND

Corneal abrasion is a common disorder frequently faced by ophthalmologists, emergency physicians, and primary care physicians. Ocular antibiotics are one of the management options for corneal abrasion. A comprehensive summary and synthesis of the evidence on antibiotic prophylaxis in traumatic corneal abrasion is thus far unavailable, therefore we conducted this review to evaluate the current evidence regarding this important issue.

OBJECTIVES

To assess the safety and efficacy of topical antibiotic prophylaxis following corneal abrasion. Our objectives were 1) to investigate the incidence of infection with antibiotics versus placebo or alternative antibiotics in people with corneal abrasion; and 2) to investigate time to clinical cure, defined as complete healing (re-epithelialization) of the epithelium, with antibiotics versus placebo or alternative antibiotics in people with corneal abrasion.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register; 2021, Issue 4), Ovid MEDLINE, Embase.com, PubMed, the Latin American and Caribbean Health Sciences Literature database (LILACS), ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 25 April 2021.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing antibiotic with another antibiotic or placebo in children and adults with corneal abrasion due to any cause.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology and assessed the certainty of the body of evidence for the prespecified outcomes using the GRADE classification.

MAIN RESULTS

Our search of the electronic databases yielded 8661 records. We screened 7690 titles and abstracts after removal of duplicates. We retrieved 32 full-text reports for further review. We included two studies that randomized a total of 527 eyes of 527 participants in the review. One study was conducted in Denmark, and one was conducted in India. The two studies did not examine most of our prespecified primary and secondary outcomes. The first study was a parallel-group RCT comparing chloramphenicol ocular ointment with fusidic acid ocular gels (frequency was not clearly reported). This study enrolled 153 participants older than 5 years of age with corneal abrasion in Denmark with a one-day follow-up duration. No participants had secondary infection in the fusidic acid group, whereas three (4.1%) participants in the chloramphenicol group had a slight reaction (risk ratio [RR] 0.15, 95% confidence interval [CI] 0.01 to 2.79; 144 participants; very low certainty evidence). Thirty-one (44.3%) participants in the fusidic acid arm and 34 (46.6%) participants in the chloramphenicol arm were cured (defined as the area of abrasion zero and no infection) at day 1 (RR 0.94, 95% CI 0.65 to 1.34; 144 participants; very low certainty evidence). Without providing specific data, the study reported that the degree of pain was not affected by the interventions received. The most common adverse events reported were itching and discomfort of the eye, which occurred in approximately one-third of participants in each group (low certainty evidence). A second multicenter, two-arm RCT conducted in India enrolled 374 participants older than 5 years of age with corneal abrasion who presented within 48 hours after injury. This study investigated the effect of a three-day course of either ocular ointment combinations of chloramphenicol-clotrimazole or chloramphenicol-placebo (all three times daily). At day 3, 169 (100%) participants in the chloramphenicol-clotrimazole arm and 203 (99%) out of 205 participants in the chloramphenicol-placebo arm were cured without any complication, defined as complete epithelialization of the cornea without evidence of infection (RR 1.01, 95% CI 0.99 to 1.03; 374 participants; very low certainty evidence). Four participants assigned to the chloramphenicol-placebo arm experienced mild adverse events: two participants (1%) had mild chemosis and irritation, and two (1%) had small single sterile corneal infiltrates (low certainty evidence).

AUTHORS' CONCLUSIONS

Given the low to very low certainty of the available evidence, any beneficial effects of antibiotic prophylaxis in preventing ocular infection or accelerating epithelial healing following a corneal abrasion remain unclear. Moreover, the current evidence is insufficient to support any antibiotic regimen being superior to another. There is a need for a well-designed RCT assessing the efficacy and safety of ocular antibiotics in the treatment of corneal abrasion with a particular focus on high-risk populations and formulation of interventions.

Topical pain control for corneal abrasions: A systematic review and meta-analysis

OBJECTIVES

Corneal abrasions are common ophthalmic presentations to emergency departments. Among emergency physicians and ophthalmologists, there are highly variable practice patterns with regard to management of resultant pain and discomfort. The goal of this study was to review and analyze the efficacy and safety of topical pain therapies for corneal abrasions, including topical anesthetics, nonsteroidal anti-inflammatory drugs (NSAIDs), cycloplegics, steroids, pressure patching, and the use of a bandage contact lens (BCL).

METHODS

The review followed the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. The protocol was established a priori and published on PROSPERO (CRD42020201288). MEDLINE, EMBASE, CENTRAL, and Web of Science were searched until December 31, 2020. Primary studies comparing topical pain therapies to another therapy or control were included. Primary outcomes included percentage of corneal abrasions healed at 24, 48, and 72 hours, as well as pain control at 24 and 48 hours. Secondary outcomes included use of oral analgesia and incidence of complications. Risk of bias was assessed using validated tools. Quality of evidence was assessed using the GRADE methodology.

RESULTS

Overall, 33 studies (31 randomized controlled trials [RCTs], two cohort studies) comprising 4,167 patients with corneal abrasions were analyzed. Only the data for topical NSAIDs were of adequate evidence from which to draw conclusions; topical NSAIDs demonstrated significantly reduced pain scores at 24 hours (standardized mean differences [SMD] -0.69, 95% CI = -0.98 to -0.41) and 48 hours (SMD = -0.56, 95% CI = -1.02 to -0.10) as well as 53% (95% CI = 34% to 67%) lower oral analgesia use compared to control. Based on available data, topical anesthetics, cycloplegics, patching, and the use of a BCL did not result in any significant difference in pain scores or use of oral analgesia, while no studies examined topical steroids. No interventions resulted in healing delays or significantly higher rates of complications compared to controls.

CONCLUSIONS

There was strong evidence to support that topical NSAIDs reduce pain associated with corneal abrasions in the first 48 hours and the need for oral analgesia. The existing evidence was insufficient to support or refute the use of topical anesthetics, cycloplegics, steroids, or BCL for pain control in corneal abrasions. Pressure patching was ineffective at pain reduction and may increase the risk of complications. Delays in healing or other complications were not significantly different between any intervention or control for simple, uncomplicated corneal abrasions; however, larger RCTs are required to identify any differences in rare complications.

Topical non-steroidal anti-inflammatory drugs for analgesia in traumatic corneal abrasions

BACKGROUND

Traumatic corneal abrasions are relatively common and there is a lack of consensus about analgesia in their management. It is therefore important to document the clinical efficacy and safety profile of topical ophthalmic non-steroidal anti-inflammatory drugs (NSAIDs) in the management of traumatic corneal abrasions.

OBJECTIVES

To identify and evaluate all randomised controlled trials (RCTs) comparing the use of topical NSAIDs with placebo or any alternative analgesic interventions in adults with traumatic corneal abrasions (including corneal abrasions arising from foreign body removal), to reduce pain, and its effects on healing time.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2017, Issue 2), MEDLINE Ovid (1946 to 30 March 2017), Embase Ovid (1947 to 30 March 2017), LILACS (Latin American and Caribbean Health Sciences Literature Database) (1982 to 30 March 2017), OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu/); searched 30 March 2017, ZETOC (1993 to 30 March 2017), the ISRCTN registry (www.isrctn.com/editAdvancedSearch); searched 30 March 2017, ClinicalTrials.gov (www.clinicaltrials.gov); searched 30 March 2017 and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en); searched 30 March 2017. We did not use any date or language restrictions in the electronic searches for trials.We checked the reference lists of identified trials to search for further potentially relevant studies.

SELECTION CRITERIA

RCTs comparing topical NSAIDs to placebo or any alternative analgesic interventions in adults with traumatic corneal abrasions.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed data extraction and assessed risks of bias in the included studies. We rated the certainty of the evidence using GRADE.

MAIN RESULTS

We included nine studies that met the inclusion criteria, reporting data on 637 participants.The studies took place in the UK, USA, Israel, Italy, France and Portugal. These studies compared five types of topical NSAIDs (0.1% indomethacin, 0.03% flurbiprofen, 0.5% ketorolac, 1% indomethacin, 0.1% diclofenac) to control (consisting of standard care and in four studies used placebo eye drops). Overall, the studies were at an unclear or high risk of bias (particularly selection and reporting bias). None of the included studies reported the primary outcome measures of this review, namely participant-reported pain intensity reduction of 30% or more or 50% or more at 24 hours. Four trials, that included data on 481 participants receiving NSAIDs or control (placebo/standard care), reported on the use of 'rescue' analgesia at 24 hours as a proxy measure of pain control. Topical NSAIDs were associated with a reduction in the need for oral analgesia compared with control (risk ratio (RR) 0.46, 95% confidence interval (CI) 0.34 to 0.61; low-certainty evidence). Approximately 4 out of 10 people in the control group used rescue analgesia at 24 hours. No data were available on the use of analgesia at 48 or 72 hours.One trial (28 participants) reported on the proportion of abrasions healed after 24 and 48 hours. These outcomes were similar in both arms of the trial. (at 24 hours RR 1.00 (0.81 to 1.23); at 48 hours RR 1.00 (0.88 to 1.14); low-certainty evidence). In the control group nine out of 10 abrasions were healed within 24 hours and all were healed by 48 hours. Complications of corneal abrasions were reported in 6 studies (609 participants) and were infrequently reported (4 complications, 1 in NSAID groups (recurrent corneal erosion) and 3 in control groups (2 recurrent corneal erosions and 1 corneal abscess), very low-certainty evidence). Possible drug-related adverse events (AEs) were reported in two trials (163 participants), with the number of adverse events low (4 AEs, 3 in NSAID group, including discomfort/photophobia on instillation, conjunctival hyperaemia and urticaria, and 1 in the control group, corneal abscess) very low-certainty evidence.

AUTHORS' CONCLUSIONS

The findings of the included studies do not provide strong evidence to support the use of topical NSAIDs in traumatic corneal abrasions. This is important, since NSAIDs are associated with a higher cost compared to oral analgesics. None of the trials addressed our primary outcome measure of participant-reported pain intensity reduction of 30% or more or 50% or more at 24 hours.

Efficacy of Topical Analgesics in Pain Control for Corneal Abrasions: A Systematic Review

Corneal abrasions are one of the most common ocular injuries seen in the emergency department. While most patients with corneal abrasions complain of excruciating pain, permanent sequelae may develop if not managed properly. The use of topical antibiotics and other standards of treatment have greatly reduced the incidence of complications. However, there is still a lack of consensus regarding the proper management of pain in corneal abrasions. Proposed analgesics for the control of corneal abrasion pain include topical nonsteroidal anti-inflammatory drugs (NSAIDs), topical anesthetics, and topical cycloplegics. For this review, ten published randomized controlled trials were identified, focusing on the efficacy and safety of different topical analgesics used in treating corneal abrasions.  Six of the trials focused on topical NSAIDs, three on topical anesthetics, and one on topical cycloplegics. There were mixed results regarding the efficacy of topical analgesics in reducing pain in patients with corneal abrasions. This review of the literature revealed that topical NSAIDs produced reductions in pain symptoms, whereas topical anesthetics and cycloplegics did not demonstrate significant improvements in either healing rates or pain control. Thus, this evidence supports the use of topical NSAIDs in the standard management of corneal abrasions. Unfortunately, the power of these studies is largely limited by small sample sizes. Larger studies must be conducted before topical analgesics can be recommended or discouraged for pain management in corneal abrasions. However, based on this review of the literature, the use of topical NSAIDs does not appear to complicate wound healing, and thus remains a safe option in patients desiring medical treatment.  

Inhibition of peripheral nociceptors by aminoglycosides produces analgesia in inflammatory pain models in the rat

Aminoglycosides (AGs) modulate nociceptors and ionic channels expressed in sensory neurons. The AG applied in situ could be useful to alleviate hyperalgesia in animal models of inflammatory pain. We tested streptomycin (ST) and neomycin (NEO) as analgesic agents applied in situ in rat paw inflammation caused by formalin or carrageenan administration. The action of ST and NEO on the action potential discharge produced by acidic stimuli in isolated dorsal root ganglion neurons was also studied in current-clamp recordings. In the formalin test, ST and NEO significantly reduced the nociceptive behaviour. ST reduced the N-(4-methyl-2-quinazolinyl)-guanidine (GMQ)-induced nociceptive behaviour, and NEO diminished the hyperalgesia to thermonociception and mechanonociception produced by CAR. In the current-clamp experiments, ST and NEO reduced the generation of action potentials when an acidic solution was applied. We conclude that ST and NEO produce analgesia to inflammatory pain, an effect that is due in part to the inhibition of ASIC activation in sensory neurons.

Lack of consensus on corneal abrasion management: results of a national survey

Objectives:

Our objective was to determine the practice patterns of Canadian emergency physicians with respect to the management of traumatic corneal abrasions.

Methods:

After developing our instrument and pilot testing it on a sample of emergency residents, we randomly surveyed 470 members of the Canadian Association of Emergency Physicians, using a modified Dillman technique. We distributed a pre-notification letter, an 18-item survey, and appropriate follow-up surveys to non-responders. Those members with an email address (n= 400) received a Web-based survey, and those without (n= 70) received a survey by post. The survey focused on the indications and utilization of analgesics (oral and topical), cycloplegics, eye patches and topical antibiotics.

Results:

Our response rate was 64% (301/470), and the median age of respondents was 38 years. Most (77.7%) were male, 71.8% were full-time emergency physicians, 76.5% were emergency medicine certified, and 64.4% practised in teaching hospitals. Pain management preferences (offered usually or always) included oral analgesics (82.1%), cycloplegics (65.1%) and topical nonsteroidal anti-inflammatory drugs (NSAIDs) (52.8%). Only 21.6% of respondents performed patching, and most (71.2%) prescribed topical antibiotics, particularly for contact lens wearers and patients with ocular foreign bodies. Two-thirds of the respondents provided tetanus toxoid if a foreign body was present, and 46.2% did so even if a foreign body was not present. Most respondents (88.0%) routinely arranged follow-up.

Conclusions:

This national survey of emergency physicians demonstrates a lack of consensus on the management of traumatic corneal abrasions. Further study is indicated to determine the optimal treatment, particularly regarding the use of topical NSAIDs.

The Eye Sensation Scale: an ophthalmic pain severity measure

PURPOSE

The aim was to develop a single-item, categorical ophthalmic pain severity scale.

METHODS

Focus groups were held with people who had experienced ophthalmic pain. Participants described their ophthalmic pain experiences with reference to level of severity, and commented on proposed pain scale designs. Thematic analysis of transcripts, and participants' category choices and scale preferences, were used to determine the number of response categories and labels chosen for the instrument. The final instrument was evaluated using a mail-out questionnaire.

RESULTS

Five ophthalmic pain domains were identified: intensity; nature (including subdomains: physical sensation, temporal patterning, simile/metaphor); physical effects; emotional effects; and behavioral effects. The most frequent descriptors were physical sensation (n = 160), behavioral effects (n = 87), and physical effects (n = 68). Participants preferred a five-category scale. The higher frequency severity descriptors used by the participants formed the basis for the category labels for the instrument ("extreme," "severe," "moderate," "mild," "none"). Notably, many participants rejected the word "pain" in favor of "discomfort" or "light sensitivity." Participants commonly linked severity and nature descriptors; however, the same nature descriptor (e.g., "ache" or "scratching") did not confer the same pain severity between participants.

CONCLUSIONS

A five-category scale was chosen for assessing the severity of ophthalmic sensations: the Eye Sensation Scale. The scale involves rating the severity of the ophthalmic sensation that is most important to the patient and provides the opportunity to describe other attributes or effects of the sensation. Evaluation indicated the adequacy of the final instrument.

Effects of the topical treatment with NSAIDs on corneal sensitivity and ocular surface of Sjögren's syndrome patients

AIM AND PURPOSE

To evaluate the effects of two NSAIDs on corneal sensitivity and ocular surface in Sjögren's syndrome (SS) patients.

METHODS

In all, 20 SS patients with epithelial corneal defects, were randomly divided into two groups: group 1 (10 females, age 35-63 years), treated with 0.1% indomethacin, one drop three times a day; group 2 (nine females, one male, age 38-65 years) treated with 0.1% diclofenac, at the same regimen. No systemic NSAIDs were allowed. Use of tear substitute was allowed. Corneal sensitivity, corneal staining, BUT, and ocular discomfort, were evaluated before and after 15, 30 days of treatment and 7 days after NSAID discontinuation. For statistical analysis, the Student's t-test and Mann-Whitney U test were used.

RESULTS

Both groups showed at day 30 a statistically significant reduction of corneal sensitivity (P<0.05), although the diclofenac-treated group showed a statistically significant lower sensitivity if compared to the indomethacin-treated group (P<0.05). Corneal fluorescein score showed a statistically significantly worst alteration in group 2, 7 days after the discontinuation of the therapy (P=0.02). The ocular discomfort score was statistically significantly reduced in both groups starting from day 15 (P<0.05).

DISCUSSION

The results indicate that NSAIDs can be useful in resolving symptoms of ocular discomfort in SS patients. However, they should be used with caution and under close monitoring, and the treatment should be promptly discontinued if corneal epithelial defects develop or worsen during treatment.

Painful Dilemmas: An Evidence-based Look at Challenging Clinical Scenarios

Difficult clinical decisions are a part of every emergency practitioner's life. Dealing with difficult patients and recalcitrant consultants is seldom enjoyable, but can be made more palatable through the use of some of the clinical strategies contained in this article. Knowledge of the current best evidence and a willingness to discard outdated practice ideas will help ensure that emergency practitioners continue to provide state-of-the-art medical care. Expressions of care, concern, and respect for patients' problems, and development of a therapeutic alliance with these patients will maximize patient, and ultimately physician, satisfaction.

Effect of topical administration of 1% morphine sulfate solution on signs of pain and corneal wound healing in dogs

OBJECTIVE

To evaluate the effect of topical application of a 1% morphine sulfate solution (MSS) on signs of pain and wound healing in dogs with corneal ulcers and examine normal corneas immunohistochemically for the presence of mu and delta opioid receptors.

ANIMALS

12 dogs.

PROCEDURE

A 7-mm superficial corneal ulcer was surgically created in the right eye (OD) of 10 dogs, after which gentamicin solution and 1% MSS (n = 6) or saline solution (4) was administered topically OD 3 times daily. Blepharospasm, tearing, conjunctival hyperemia, aqueous flare, esthesiometer readings, and pupil size were recorded before and 30 minutes after treatment in all dogs. Ulcer size and days to completion of healing were recorded. Corneas from 4 treated and 3 control dogs were evaluated histologically. Normal canine corneas from 2 dogs not used in the study were evaluated immunohistochemically for the presence of mu and delta opioid receptors.

RESULTS

Dogs treated with MSS had significantly less blepharospasm and lower esthesiometer readings than did control dogs. Duration of ulcer healing and findings of histologic evaluation of corneas did not differ between groups. Numerous delta and infrequent mu opioid receptors were identified in the corneal epithelium and anterior stroma of normal corneas.

CONCLUSIONS AND CLINICAL RELEVANCE

Topical use of 1% MSS in dogs with corneal ulcers provided analgesia and did not interfere with normal wound healing. Both mu and delta opioid receptors were identified in normal corneas of dogs, although the mu receptors were present only in small numbers.

Evidence-based emergency medicine. Update: do ophthalmic nonsteroidal anti-inflammatory drugs reduce the pain associated with simple corneal abrasion without delaying healing?

INTRODUCTION

Some studies have suggested that ophthalmic nonsteroidal anti-inflammatory drugs (NSAIDs) decrease the pain associated with corneal abrasions without impairing healing. This evidence-based emergency medicine (EBEM) critical appraisal reviews the literature, including additional studies appearing since the publication of an earlier EBEM review in 1999.

METHODS

The updated search for randomized controlled trials from 1999 to 2002 complemented the previous 1966 to 1999 search. The methodologic quality of the studies was assessed. Qualitative methods were used to summarize the study results.

RESULTS

The search identified 3 studies not included in the previously published review of ophthalmic NSAIDs, yielding a total of 5 blinded, randomized, placebo-controlled trials involving NSAIDs for corneal abrasions. The methodologic quality of the new studies was somewhat higher than that of the 2 original studies and was rated as "good" to "strong." The qualitative summary indicates that NSAIDs provide greater pain relief and improvement of other subjective symptoms when compared with placebo. However, whether the reduction of pain, as measured by visual analog pain scales, exceeds the minimal clinically significant difference is equivocal. The use of ophthalmic NSAIDs may decrease the need for sedating analgesics.

CONCLUSION

Ophthalmic NSAIDs appear to be useful for decreasing pain in patients with corneal abrasions who can afford the medication and who must return to work immediately, particularly where potential opioid-induced sedation is intolerable.