Topical Ocular TRPV1 Antagonist SAF312 (Libvatrep) for Postoperative Pain After Photorefractive Keratectomy

Purpose

Evaluation of safety and efficacy of topical ocular SAF312 (Libvatrep) in post-photorefractive keratectomy (PRK) pain.

Methods

In this placebo (vehicle)-controlled, participant- and investigator-masked study, 40 participants were randomized (1:1) to two treatment sequences in a bilateral PRK crossover design (SAF312 2.5% followed by vehicle [or vice versa], one eye drop, four times daily for 72 hours after PRK). Primary endpoints were visual analog scale (VAS) pain scores at 6 hours after first drop of study drug and average VAS scores over 0 to 12 hours postoperatively. Secondary endpoints included postoperative oral rescue medication (ORM) use and adverse events (AEs).

Results

All 40 participants completed the study. Both primary endpoints were met; mean difference in VAS pain scores between SAF312- and vehicle-treated eyes was -11.13 (P = 0.005, -25%) at 6 hours postoperatively and -8.56 (P = 0.017, -22%) over 0 to 12 hours. Mean VAS pain scores with SAF312 were consistently lower than with vehicle from 1 hour postoperatively up to 30 hours (P ≤ 0.10 observed in 8/11 time points). Less ORM was taken with SAF312 up to 0 to 72 hours postoperatively, with a trend of fewer participants taking ORM at 0 to 24 hours postoperatively with SAF312 versus vehicle. No serious AEs were reported. All ocular AEs were mild and transient, and none were drug related. SAF312-treated eyes showed no delay in wound healing and had a lower grade 4 conjunctival hyperemia 24 hours postoperatively versus vehicle-treated eyes.

Conclusions

SAF312 was well tolerated and effective in reducing ocular pain post-PRK.

Translational Relevance

Topical SAF312 presents a new therapeutic option for patients undergoing PRK.

The use of topical nalbuphine in different concentrations to control pain after photorefractive keratectomy

PURPOSE

This is a randomized controlled study aiming to evaluate the safety and efficacy of two different concentrations of topical nalbuphine hydrochloride, when used to relieve pain in the first days following photorefractive keratectomy (PRK).

METHODS

This is a prospective double blinded randomized clinical trial that included 189 patients who had PRK for correction of low and moderate refractive errors. Patients were randomly assigned to three groups according to the eye drops given to relieve pain in the first three postoperative days; the first group received topical nalbuphine with a concentration of 2 mg/ml (Group A = 64 patients), the second group received topical nalbuphine in a concentration of 1 mg/ml (Group B = 69 patients) and the third group received topical artificial tears only (Group C = 56 patients).The patients were asked to rate their pain daily using a numeric rating scale and to record the number of drops instillation times/day. The time needed for complete epithelial healing, best-corrected visual acuity (BCVA) and spherical equivalent after three months were recorded in each group.

RESULTS

In the first three days, there was a statistically significant difference in pain score among the three groups with lower values in the two topical nalbuphine groups when compared with the control group receiving artificial tears. Moreover, the higher concentration group showed significantly lower pain score and less number of drops used /day in comparison with the lower concentration group.There were no statistically significant differences in epithelial healing time, BCVA and spherical equivalent after three months among the three groups.

CONCLUSION

The use of topical nalbuphine is effective in relieving pain in the first few days following PRK and this pain relief is not associated with any compromise regarding epithelial healing nor refractive outcome. The pain control with 2 mg/ml concentration is significantly higher than that with 1 mg/ml concentration of nalbuphine. Trial registration numberISRCTN21394752 https://doi.org/10.1186/ISRCTN21394752 The trial is retrospectively registered in ISRCTN registry at March 08, 2021.

Comparison of the effect of removing bandage contact lens on the days 3 and 5 following photorefractive keratectomy

AIM

To compare the outcomes of removing bandage contact lens (BCL) on days 3 and 5 after photorefractive keratectomy (PRK).

METHODS

One hundred patients who underwent PRK (a total of 200 eyes) were enrolled in the present study. The subjects were assigned to two groups. Group 1 consisted of the right eyes of subjects and bandage contact lenses removal were on the 3rd day; Group 2 consisted of the fellow eyes of same subjects and removed bandage contact lenses on the 5th day after PRK. Then, data obtained from both groups were compared. To evaluate complications, the subjects underwent a slit-lamp examination in all visits.

RESULTS

Filamentary keratitis was observed in one eye in both groups. The frequency of haze was higher in group 1; however, it was not significant between the two groups. Using mixed model analysis, significant differences were observed in the rate of complications as well as pain and eye discomfort scores between the groups (P < 0.05). No major complication was reported.

CONCLUSION

Majority of post-PRK corneal epithelial defect is healed on day 3. However, keeping BCL for 5 days postoperatively instead of the three days produces a slightly lower rate of total complication.

Early clinical outcomes and comparison between trans-PRK and PRK, regarding refractive outcome, wound healing, pain intensity and visual recovery time in a real-world setup

PURPOSE

To compare early clinical outcomes of single-step transepithelial photorefractive keratectomy (tPRK) and photorefractive keratectomy (PRK) regarding refractive outcome, visual acuity, wound healing, pain intensity and visual recovery time.d.

METHODS

In this prospective clinical observational study 200 eyes of 100 consecutive patients with mild to moderate myopia with or without mild astigmatism were included. One hundred eyes each were either treated with StreamLight™ tPRK or PRK with the WaveLight® EX500 excimer laser. Visual acuity (Decimal) was assessed preoperatively and at day 4, 7 and 6 weeks postoperatively. Wound healing (hours between surgery and complete epithelial closure) was monitored at the slit lamp. At day 4, patients subjectively rated the maximum pain intensity within the last 4 days using a numerical pain rating scale (0-15).

RESULTS

Visual recovery was significantly faster in the tPRK group. At days 4 and 7, the mean monocular UCDVA was significantly better in the tPRK group than in the PRK group (p < 0.001). Four days after surgery 72 % of eyes in the tPRK group but no eye in the PRK had a UCDVA of 0.7 or better. At six weeks postoperatively, a UCDVA of 1.0 or better was achieved in both groups. Complete epithelial wound closure was achieved significantly faster in the tPRK group (p < 0.0001) and maximum pain level within the first 4 days after surgery was significantly lower in the tPRK group (p < 0.0001). No patient had lost a line of BCDVA and no complications or adverse effects were observed.

CONCLUSIONS

According to our early clinical results, both treatments options appear to be safe and effective methods for the correction of low to moderate myopia with and without astigmatism. However, in our study, StreamLight™ tPRK offered faster visual recovery and epithelial healing and was associated with less pain compared to PRK. It can therefore be considered a good treatment option for patients who refuse or are not eligible for Femto-LASIK, but at the same time demand a faster and more comfortable recovery time than PRK can offer.

Transepithelial Photorefractive Keratectomy for Low to Moderate Myopia in Comparison with Conventional Photorefractive Keratectomy

Purpose:

To compare the effectiveness, safety and stability of the results of transepithelial photorefractive keratectomy (tPRK) with conventional photorefractive keratectomy (PRK) for low to moderate myopia.

Methods:

In this prospective non-randomized case-control study, patients with low to moderate myopia were assigned to the tPRK group (cases) or the PRK group (controls). In the tPRK group, eyes were treated using the Amaris excimer laser (SCHWIND eye-tech-solutions GmbH and Co. KG, Germany). Outcome measures included postoperative pain using McGill Pain Questionnaire, epithelial healing time, uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction, and safety and efficacy indexes which were compared between the study groups.

Results:

Three hundred forty eyes of 170 patients were enrolled in this study. Each study group comprised of 170 eyes of 85 patients. There was a significant difference between the two groups regarding the postoperative pain scores in favor of the tPRK group (P = 0.04). The tPRK group had a shorter epithelial healing time than the conventional PRK group postoperatively (P = 0.01). Mean UCVA was significantly better in the case group than in the control group at the postoperative month 2 (P = 0.01). Regarding the safety and efficacy indexes, the tPRK group had better results than the conventional PRK group (P < 0.01 for both comparisons).

Conclusion:

Transepithelial PRK seems to be superior to conventional PRK for treatment of low to moderate myopia in terms of postoperative pain, epithelial healing time, visual recovery and safety and efficacy indexes.

The Toxicity of Nonsteroidal Anti-inflammatory Eye Drops against Human Corneal Epithelial Cells in Vitro

This study investigated the toxicity of commercial non-steroid anti-inflammatory drug (NSAID) eye solutions against corneal epithelial cells in vitro. The biologic effects of 1/100-, 1/50-, and 1/10-diluted bromfenac sodium, pranoprofen, diclofenac sodium, and the fluorometholone on corneal epithelial cells were evaluated after 1-, 4-, 12-, and 24-hr of exposure compared to corneal epithelial cell treated with balanced salt solution as control. Cellular metabolic activity, cellular damage, and morphology were assessed. Corneal epithelial cell migration was quantified by the scratch-wound assay. Compared to bromfenac and pranoprofen, the cellular metabolic activity of diclofenac and fluorometholone significantly decreased after 12-hr exposure, which was maintained for 24-hr compared to control. Especially, at 1/10-diluted eye solution for 24-hr exposure, the LDH titers of fluorometholone and diclofenac sodium markedly increased more than those of bromfenac and pranoprofen. In diclofenac sodium, the Na(+) concentration was lower and amount of preservatives was higher than other NSAIDs eye solutions tested. However, the K(+) and Cl(-) concentration, pH, and osmolarity were similar for all NSAIDs eye solutions. Bromfenac and pranoprofen significantly promoted cell migration, and restored wound gap after 48-hr exposure, compared with that of diclofenac or fluorometholone. At 1/50-diluted eye solution for 48-hr exposure, the corneal epithelial cellular morphology of diclofenac and fluorometholone induced more damage than that of bromfenac or pranoprofen. Overall, the corneal epithelial cells in bromfenac and pranoprofen NSAID eye solutions are less damaged compared to those in diclofenac, included fluorometholone as steroid eye solution.

Comparison of the effect of cycloplegic versus NSAID eye drops on pain after photorefractive keratectomy

PURPOSE

To compare the effect of Homatropine and Diclofenac eye drops for reducing pain after photorefractive keratectomy (PRK).

METHODS

This randomized, double-masked, interventional study included 32 patients (64 eyes) who underwent bilateral PRK. After operation, patients received Homatropine eye drops in one eye and Diclofenac eye drops in the fellow eye for 48 h. The level of pain was evaluated using visual analogue scale (VAS), verbal rating scale (VRS), and pain rating index (PRI) at 0.5, 24, and 48 h after operation.

RESULTS

The level of pain was statistically similar between the two eyes half an hour after operation; however, Diclofenac eyes had significantly less pain 24 h after operation (1.7 ± 1.4 vs 5.8 ± 2.1, P < 0.001 for VAS, 0.6 ± 0.6 vs 2.4 ± 1.1, P < 0.001 for VRS, and 3.4 ± 3.4 vs 12.0 ± 6.9, P < 0.001 for PRI, respectively). Also, 48 h after surgery, the pain scores were less in the Diclofenac eyes (1.6 ± 1.8 vs 3.4 ± 2.8, P < 0.001 for VAS, 0.6 ± 0.6 vs 1.2 ± 0.9, P < 0.001 for VRS, and 3.3 ± 3.7 vs 6.5 ± 6.2, P < 0.001 for PRI). No case with delayed epithelial healing in both groups was observed.

CONCLUSION

The effect of Homatropine seems to be lower compared to Diclofenac for reducing pain after photorefractive keratectomy.

Efficacy and safety of pain relief medications after photorefractive keratectomy: review of prospective randomized trials

The objective of this review was to provide a comprehensive overview and comparison of results from all prospective randomized trials published to date of medications used to treat pain after photorefrative keratectomy (PRK). A PubMed database search revealed 23 prospective and randomized studies. They included the following classes of medications: nonsteroidal antiimflammatory drugs (NSAIDs), anesthetics, opiates, acetaminophen, gabapentin, and pregabalin. The studies found that although the efficacy of drugs tended to be similar, tetracaine 1% and nepafenac 0.1% tended to have the most analgesic effect. Delayed corneal reepithelialization was a common side effect of both topical anesthetics and topical NSAIDs. Tetracaine 1% resulted in the most significant delay in reepithelialization when tested against placebo control compared with other topical medications tested against placebo. Concomitant use of topical NSAIDs and topical anesthetics, especially tetracaine, may have to be avoided to minimize the risk for delayed corneal healing.

FINANCIAL DISCLOSURE

Neither author has a financial or proprietary interest in any material or method mentioned.

Comparing the Efficacy of Ophthalmic NSAIDs in Common Indications

Objective: To review the commercially available ophthalmic nonsteroidal anti-inflammatory drugs (NSAIDs), identify opportunities for therapeutic substitutions within and outside of their Food and Drug Administration (FDA)-approved indications, and identify clinically superior drugs within the class for specific indications. Data Source: A PubMed search (1992 through January 2014) was performed on the terms diclofenac, ketorolac, flurbiprofen, bromfenac, and nepafenac. Study Selection and Data Extraction: Clinical trials, meta-analyses, and review articles were evaluated if they were written in English and pertained to human subjects. Studies were excluded if they were in vitro studies, solely evaluated pharmacokinetic or pharmacodynamic properties, did not relate to the topical ophthalmic route, did not evaluate the FDA-approved indications of any available ophthalmic NSAID, or compared a reviewed drug with a nonreviewed drug (without placebo comparison). Data Synthesis: A total of 67 articles met the criteria for evaluation. Article quality, study design, and dosing of the medications were assessed to determine the clinical applicability of the results. The quality of the article was determined using the Oxford Centre for Evidence-based Medicine Levels of Evidence 1. Conclusions: Many formulations of the 5 reviewed NSAIDs have been studied across the 4 primary indications. These indications are (1) pain and inflammation associated with cataract surgery, (2) pain associated with corneal refractive surgery, (3) inhibition of intraoperative miosis, and (4) seasonal allergic conjunctivitis. Several studies have directly compared drugs within this class and have identified instances in which certain selections are therapeutically superior or equivalent to another. This information provides practitioners with guidance in selecting an optimal medication.

Effect of Homatropine eye drops on pain after photorefractive keratectomy: A pilot study

PURPOSE

To assess the effect of homatropine eye drops on pain after photorefractive keratectomy (PRK).

METHODS

This randomized, double masked, interventional study included 15 patients (30 eyes) who underwent bilateral PRK. After operation, patients received homatropine eye drops, 4 times daily in only one eye (homatropine eye). The level of pain was evaluated using visual analogue scale (VAS), verbal rating scale (VRS) and pain rating index (PRI) at 0.5, 24 and 48 h after operation.

RESULTS

The level of pain was statistically similar between the two eyes half an hour after operation, however, homatropine eyes had significantly less pain 24 h after operation compared to fellow eyes (2.5 ± 1.9 vs 5.3 ± 2.5, P = 0.004 for VAS, 2.0 ± 1.2 vs 3.2 ± 0.9, P = 0.023 for VRS, and 9.4 ± 5.7 vs 16.0 ± 9.0, P = 0.031 for PRI). Also, 48 h after surgery, the pain scales were less in the homatropine eyes (2.3 ± 1.7 vs 4.0 ± 2.1, P = 0.014 for VAS, 1.6 ± 1.0 vs 2.5 ± 1.0, P = 0.038 for VRS, and 6.8 ± 5.7 vs 12.0 ± 8.9, P = 0.005 for PRI). No delayed epithelial healing was observed.

CONCLUSION

Homatropine eye drops may be useful for reducing pain after Photorefractive keratectomy.

Pain and Its Determinants in Photorefractive Keratectomy

PURPOSE

To assess the determinants of early postoperative pain in photorefractive keratectomy.

DESIGN

A prospective cross-sectional study.

METHODS

One hundred and four myopic-astigmatic patients undergoing bilateral standard photorefractive keratectomy were evaluated for early postoperative pain severity. On day 1 postoperatively, the level of pain experienced was reported by the patient on a visual analog scale of 0 to 10. At the preoperative interview, data were collected on clinical, demographic, and social characteristics to find potential pain determinants.

RESULTS

The median reported pain level was 3. About 20% of subjects reported a pain score of 6 or higher, and 2.9% (6 eyes of 4 patients) reported the highest pain score. The presence of external eye inflammatory signs was associated with higher levels of pain (P < 0.001). Patients with a higher body mass index reported more severe pain (P = 0.006). An inverse association was found between pain and harmful lifestyle choices (P = 0.008). Demographic characteristics, history of contact lens wear, history of major operation, past experience of severe pain, knowledge about the operation's adverse effects, preoperative insomnia, preoperative anxiety, operative factors, and refractive indices were not related to the severity of pain experienced (all P > 0.05).

CONCLUSIONS

The association of pain with ocular surface inflammation suggests that inflammatory processes have a role in early postoperative pain, supporting the use of anti-inflammatory agents for pain management. Prescription of weight-adjusted dosages of analgesics is recommended on the basis of the association between severity of postoperative pain and body mass index.

Effects of nonsteroidal ophthalmic drops on epithelial healing and pain in patients undergoing bilateral photorefractive keratectomy (PRK)

The present study, which was designed as a prospective, double-masked, randomized, controlled, single-site study, was conducted to compare the effects of 3 approved ophthalmic nonsteroidal anti-inflammatory drugs-nepafenac ophthalmic suspension 0.1% (Nevanac; Alcon Laboratories, Inc., Fort Worth, Tex), ketorolac tromethamine ophthalmic solution 0.4% (Acular LS; Allergan, Irvine, Calif), and bromfenac 0.09% (Xibromtrade mark; ISTA Pharmaceuticals, Irvine, Calif)-on corneal reepithelialization and postoperative pain control in patients undergoing photorefractive keratectomy. In addition to nonsteroidal anti-inflammatory drugs, each patient received an antibiotic-moxifloxacin hydrochloride ophthalmic solution 0.5% (nepafenac group) or gatifloxacin ophthalmic solution 0.3% (ketorolac and bromfenac groups). All treatments were administered 3 times daily beginning 1 d preoperatively and continuing for 1 wk postoperatively; prednisolone acetate 1.0% was administered concurrently 4 times daily. Bandage contact lenses were replaced at each postoperative visit for corneal staining and epithelial defect grading. Self-evaluation of pain relief was recorded on postoperative days 1 and 3 with the use of a visual analog scale. A total of 29 patients (58 eyes) were enrolled and underwent bilateral custom photorefractive keratectomy. Mean time to reepithelialization was 5.50+/-1.59 d for the nepafenac 0.1% group, 5.62+/-1.23 d for the ketorolac 0.4% group, and 7.25+/-2.53 d for the bromfenac 0.09% group. A significant difference was detected between nepafenac 0.1% and bromfenac 0.09% and between ketorolac 0.4% and bromfenac 0.09% (P<.05). Significant reductions in pain scores were observed with nepafenac 0.1% on day 1 (-1.13) and day 3 (-1.32), ketorolac 0.4% on day 3 (-0.88), and bromfenac 0.09% on day 3 (-0.83). No adverse events were reported. Eyes treated with nepafenac 0.1% or ketorolac 0.4% achieved complete reepithelialization significantly faster than those treated with bromfenac 0.09%. Daily contact lens removal and application of fluorescein may have delayed reepithelialization in the overall population; however, the effect would have been the same in all 3 groups. Pain relief with nepafenac 0.1% was achieved sooner than with ketorolac 0.4% or bromfenac 0.09%.

Double-masked study of the effects of nepafenac 0.1% and ketorolac 0.4% on corneal epithelial wound healing and pain after photorefractive keratectomy

Two NSAIDs--nepafenac 0.1% and ketorolac tromethamine 0.4%-were compared in terms of their effects on corneal reepithelialization and pain after photorefractive keratectomy (PRK) in a randomized, double-masked, contralateral eye, multicenter study. A total of 40 healthy adult patients who were undergoing sequential bilateral PRK received nepafenac 0.1% and ketorolac 0.4% in contralateral eyes, 1 drop 3 times daily for 3 d after bandage contact lens insertion. Patients were assessed on postoperative days 1, 3, 4, 5, and 7. At each visit, patients provided a general rating of pain. Each patient also assessed the sensation of each eyedrop following instillation (after-drop pain, irritation, burning/stinging, and overall comfort). Starting on day 3, epithelial defect size was assessed. Mean epithelial defect size was similar between treatments at each postoperative visit (P>.05). The average time-to-healing was 4.18 d for nepafenac 0.1% and 4.00 d for ketorolac 0.4% (P=.3134). No statistical difference was observed between nepafenac 0.1% and ketorolac 0.4% in mean postoperative pain scores (P>.05). On day 3, the nepafenac 0.1% group had significantly lower mean sensation scores than did the ketorolac 0.4% group for after-drop pain (P=.0090), irritation (P=.0007), and burning/ stinging (P=.0003). Mean overall comfort score was also significantly better for nepafenac 0.1% on day 3 (7.43 vs 6.41; P<.0001). Nepafenac 0.1% and ketorolac 0.4% provide postoperative pain relief after PRK surgery without associated adverse effects on corneal epithelial healing. Nepafenac 0.1% treatment may offer greater comfort upon instillation in patients who have undergone PRK.

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.

Single dose oral indometacin for the treatment of acute postoperative pain

BACKGROUND

Indometacin is a non-steroidal anti-inflammatory drug (NSAID) used most commonly for the treatment of inflammation and pain resulting from rheumatic disease (arthritis), and less commonly in postoperative pain management. When taken for chronic pain conditions, indometacin has been associated with a high incidence of adverse events. The benefits and harms of orally-administered indometacin for postoperative pain are not clear.

OBJECTIVES

To determine the efficacy of a single dose of oral indometacin compared with placebo in treating acute postoperative pain in adults, and to analyse information relating to adverse events.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials in The Cochrane Library (Issue 3, 2004), MEDLINE, EMBASE and the Oxford Pain Relief Database for relevant studies. Additional studies were sought from the reference lists of retrieved reports.

SELECTION CRITERIA

Studies were included in the review if they were randomised, double blind, placebo-controlled clinical trials using a single oral dose of indometacin in adults with acute postoperative pain.

DATA COLLECTION AND ANALYSIS

Trials were assessed independently by two authors. Pain relief or pain intensity data were extracted and converted into dichotomous information to give the number of patients with at least 50% pain relief over four to six hours. The relative benefit for at least 50% pain relief was calculated.

MAIN RESULTS

One trial of 59 women with post-episiotomy pain met the inclusion criteria. The dose of indometacin assessed against placebo was 50 mg, and the results concluded that indometacin was not significantly better than placebo for relieving postoperative pain at four to six hours. There was insufficient information to conduct further efficacy analyses or assess adverse events.

REVIEWERS' CONCLUSIONS

Conclusions about the clinical efficacy of indometacin for postoperative cannot be made until more trials are conducted for a variety of surgical procedures, and different doses of indometacin are assessed.

Effect of Topical 0.1% Indomethacin Solution Versus 0.1% Fluorometholon Acetate on Ocular Surface and Pain Control Following Laser Subepithelial Keratomileusis (LASEK)

PURPOSE

To compare the effect of topical 0.1% indomethacin solution versus 0.1% fluorometholon acetate in the early postoperative period after LASEK treatment.

METHODS

One hundred thirty-five patients undergoing LASEK, having been randomized in a double-masked manner into 2 groups (1 receiving indomethacin and 1 fluorometholon), were evaluated 2-4 days before and 4 days after treatment. We examined corneal fluorescein staining and corneal esthesiometry; the level of pain experienced was reported by the patient on a visual pain scale. In addition, haze was evaluated at 14 +/- 1 weeks after surgery.

RESULTS

The pain level and corneal fluorescein staining were significantly less in the indomethacin group. Corneal esthesiometry was reduced to the same extent in the 2 groups. There were no statistically significant differences in haze presentation between the 2 groups.

CONCLUSION

Our study highlights the efficacy of indomethacin solution compared with fluorometholon as a pain reducer after LASEK treatment and suggests that indomethacin is associated with a faster epithelial healing process.

Late corneal perforation after photorefractive keratectomy associated with topical diclofenac: involvement of matrix metalloproteinases

OBJECTIVE

To report a case of a 50-year-old man who was initially seen with a corneal perforation in his right eye 2 months after a photorefractive keratectomy (PRK) procedure and to discuss the roles of topical diclofenac and matrix metalloproteinases (MMPs).

DESIGN

Case report with tissue analysis.

MAIN OUTCOME MEASURES

Ocular examination, diagnostic workup, surgical treatment, and histologic, immunofluorescent, zymography, and real time-polymerase chain reaction studies on corneal button.

RESULTS

Slit-lamp examination of the right eye revealed a 4-mm diameter area of central corneal thinning with a 2-mm diameter perforation at its center. Predisposing factors included prolonged postoperative topical diclofenac therapy for more than 2 months and a 10-year history of well-controlled diabetes mellitus. An extensive diagnostic workup ruled out a systemic autoimmune disease. A penetrating keratoplasty was performed. Results of immunohistochemical studies of the corneal button showed stromal accumulation of temporary type III and IV collagens, MMP-3, and MMP-9 in the anterior wounded stroma and MMP-9 in the basal corneal epithelial cells of the leading edge. Differential activity and expression of MMP-2 and MMP-9 were found between the central and peripheral corneal buttons.

CONCLUSIONS

Prolonged use of diclofenac and diabetes mellitus might be responsible for the corneal perforation after PRK in our patient. MMP-9 and MMP-3 might be involved in delayed wound closure and corneal melting.

Ocular drug permeation following experimental excimer laser treatment on the isolated pig eye

Excimer laser photorefractive keratectomy (PRK) is a well-established procedure which is frequently applied to correct myopia. Since structural alterations of the corneal epithelium occur after the treatment, a different drug permeation can be assumed. To investigate the effects of PRK on drug permeation, excimer laser ablations with varying depths were performed on isolated pig eyes. The permeation of lipophilic (diclofenac-sodium; D-Na) and hydrophilic (pilocarpine-hydrochloride; P-HCl model drugs were studied in vitro. Under these experimental conditions, P-HCl demonstrated a significant (p < 0.05) enhancement of permeation in relation to the ablation depth. In contrast, corneal epithelial thickness scarcely influenced the permeation rate of D-Na. Not until removing the entire epithelium did a significantly increased permeability occur, when compared to untreated cornea. These results suggest that PRK may significantly reduce the corneal barrier function and alter pharmacokinetics of topical medication.

Saxitoxin: an anesthetic of the deepithelialized rabbit cornea

PURPOSE

The aim of the current study was to define the efficacy of saxitoxin as a corneal anesthetic in rabbits after mechanical corneal abrasion and photorefractive keratectomy (PRK).

METHODS

Twelve Dutch belted rabbits were given a single 1.2-microg dose of saxitoxin or vehicle after mechanical abrasion of the cornea. Corneal sensation was evaluated hourly for 6 hours. A second group of 12 Dutch belted rabbits was given a 1.2-microg dose of saxitoxin or vehicle every 5 hours for 30 hours after PRK. Corneal sensation was evaluated after 5, 10, 15, 20, 25, and 30 hours. Pachometry was performed before PRK and again after the epithelial defects had healed. The rate of epithelial defect closure was assessed by measuring the epithelial defect size 25, 42, 65, 88, and 113 hours after PRK.

RESULTS

A dose of 1.2 microg of saxitoxin given every 5 hours produced continuous corneal anesthesia after PRK. There was no difference in the rate of wound healing between eyes treated with saxitoxin and vehicle. There was no difference in the degree of wound healing, as measured by pachometry, between eyes treated with saxitoxin and vehicle. There were no apparent ocular or systemic toxic effects from saxitoxin administration.

CONCLUSION

At a dose of 1.2 microg, saxitoxin is a safe, effective, long-acting corneal anesthetic in rabbits after PRK.

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

PURPOSE

To evaluate the analgesic action of combined indomethacin 0.1%/gentamicin eyedrops in traumatic corneal abrasion.

METHODS

We evaluated 123 patients presenting traumatic corneal abrasion in a multicentre, randomised, double-masked study comparing two parallel treatment groups: indomethacin/gentamicin (group 1) or gentamicin alone (group 2). Study treatments were administered four times daily for 5-6 days. Pain (visual analogue scale), associated symptoms and safety were assessed.

RESULTS

Starting from a comparable level, pain was reduced by 30% in group 1 and 15% in group 2, one hour after the first instillation, and by 59% and 42% respectively after the second. The global difference in pain relief from day 0 to day 4/5 was significantly better in group 1 (p = 0.015). Associated ophthalmic symptoms showed a greater decrease in group 1 after the first instillation (p = 0.007). Both treatments were well tolerated.

CONCLUSIONS

Combined indomethacin/gentamicin eyedrops were effective and well tolerated in reducing the pain and discomfort associated with traumatic corneal abrasion.

The effect of early steroid treatment after PRK on clinical and refractive outcomes

PURPOSE

To evaluate the effects of steroid treatment administered in the first days after excimer laser keratectomy (PRK) on re-epithelialization time, postoperative pain, haze and refractive outcome.

METHODS

A randomised, double masked trial was carried out on two groups of patients (40 patients each), who underwent PRK. Group A (steroid group) received 0.1% fluorometholone acetate whereas group B (NSAID group) received 0.5% ketorolac tromethamine until re-epithelialization was completed. Subsequently, all 80 patients received the same steroid treatment: 0.1%, fluorometholone acetate for myopic corrections up to -5 D, or dexamethasone for myopic corrections exceeding -5 D. Both drugs were tapered off over approximately 3 months. Follow-up examinations were planned at 1, 3, 6, 12 months after surgery.

RESULTS

Re-epithelialization was completed after three days, without any significant difference between groups. A higher hyperopic shift was shown in the steroid group and a more severe regression was reported in the NSAID group (p<0.001). Haze was significantly reduced in the steroid group (p=0.005), especially for myopic corrections over -5 D (p=0.015). Pain was significantly reduced in the NSAID group (p=0.002).

CONCLUSION

Steroid eyedrops administered in the first days after PRK did not affect re-epithelialization time. Moreover, a modulation of the inflammatory response in this period appears to reduce haze and myopic regression in high myopic patients.

A randomized, double-masked, clinical study of the efficacy of four nonsteroidal anti-inflammatory drugs in pain control after excimer laser photorefractive keratectomy

OBJECTIVE

This study assessed the efficacy of 4 nonsteroidal anti-inflammatory drugs (NSAIDs) after excimer laser photorefractive keratectomy (PRK).

BACKGROUND

Inadequate control of pain after PRK surgery can be a severe source of distress to patients and can interfere with their willingness to undergo a second PRK procedure.

METHODS

This randomized, double-masked, placebo-controlled clinical study was conducted in 125 patients. Four NSAIDs (diclofenac, flurbiprofen, ketorolac, and indomethacin) were tested against a placebo group (artificial tears). Pain levels after PRK were quantified using Present Pain Intensity (PPI) and Pain Rating Indices based on rank values (PRI[R]) scores, both of which were calculated using patient responses to a modified McGill Pain Questionnaire. The PRI(R) consisted of 4 subscales-sensory (S), affective (A), evaluative (E), and miscellaneous (M)-as well as a total score (T).

RESULTS

Three hours after PRK, no differences in PPI scores were found between the ketorolac, diclofenac, and indomethacin groups, whereas placebo was significantly less effective than the NSAIDs. Patients who received flurbiprofen reported PPI scores that were significantly lower (P < 0.001) than those of patients who received diclofenac and indomethacin, but PPI scores in the flurbiprofen and the ketorolac groups did not differ significantly. Twenty-four hours after surgery, patients treated with flurbiprofen, ketorolac, and diclofenac reported the lowest PPI scores compared with those treated with indomethacin and placebo (P < 0.001). Moreover, flurbiprofen-treated patients also had the lowest PRI(R)T scores (P < 0.001). When the pain rating index was examined by subclass, a significantly lower PRI(R)S score was detected in the flurbiprofen group at 24 hours (P < 0.001). The PRI(R)A score was significantly higher in the placebo and indomethacin groups compared with the other groups (P < 0.001). At the 48- and 72-hour time points, flurbiprofen-treated patients again reported significantly lower PPI and PRI(R)T scores (P < 0.001 for both) in pair-wise comparisons with the other treatment groups. The number of patients who self-administered additional oral analgesics did not differ significantly between the groups. However, the mean number of analgesic tablets used was significantly higher in the placebo group than in any NSAID group (P < 0.001). The ketorolac group had the largest number of patients complaining of itching (P < 0.043). No other subjective symptoms were significantly different across groups. Finally, all NSAIDs, except flurbiprofen, prolonged the mean reepithelialization period slightly (P < 0.001).

CONCLUSIONS

Flurbiprofen appeared to be the most effective NSAID for the treatment of pain, even at 24 hours after surgery when pain was at a maximum.

The effects of the topical administration of non-steroidal anti-inflammatory drugs on corneal epithelium and corneal sensitivity in normal subjects

PURPOSE

To study the changes in the corneal epithelium and corneal sensitivity of healthy subjects after the topical administration of non-steroidal anti-inflammatory drugs (NSAIDs; diclofenac, indomethacin, flurbiprofen and ketorolac) frequently used in ocular therapy.

METHODS

A double-masked parallel clinical study was undertaken on 90 subjects (45 men, 45 women; Caucasian; age 21-46 years, mean +/- SD 27.1 +/- 5 years). The subjects were divided into six groups: group 1 was treated with placebo, group 2 with 0.1% diclofenac, group 3 with 0.1% indomethacin, group 4 with 0.03% flurbiprofen, group 5 with 0.5% ketorolac and group 6 with 0.4% oxybuprocaine. One eye was randomly treated with the study drug and the fellow eye was treated with placebo. The medications were instilled four times, at 5 min intervals. Assessment of the corneal epithelium was carried out by vital fluorescein stain before instillation and 5, 15, 30 and 60 min after instillation of the last drop. Subjective burning sensation was assessed by asking participants to rate burning on a scale from 0 (none) to 3 (severe). After 1 week, assessment of corneal sensitivity was carried out by the Cochet-Bonnet method, repeating the above scheme of instillation and measurement times.

RESULTS

None of the study drugs, with the exception of oxybuprocaine, produced evident epithelial damage. All the drugs caused a mean burning sensation greater than the placebo. The diclofenac-treated group showed a statistically significant decrease in corneal sensitivity (p < 0.001) at the measurement carried out 15 min after instillation of the last drop and lasting up to the end of the study, when the corneal anaesthesia was similar to that induced by the topical anaesthetic treatment. No significant changes were demonstrated for the other NSAIDs when compared either with the placebo-treated eyes or with the fellow eyes.

CONCLUSIONS

Despite a similar mechanism of action and analgesic activity to the other NSAIDs tested, diclofenac was able to induce a reduction in corneal sensitivity. More studies are needed to determine the mechanism of action responsible for this effect.