Long-Term Clinical Outcome of Low-Temperature Plasma Ablation Treatment for Recurrent Corneal Erosions

Purpose: To observe the therapeutic effect of low-temperature plasma ablation in treating patients with recurrent corneal erosions (RCEs). Materials and Methods: From 2020 to 2022, 35 participants with unilateral RCEs voluntarily enrolled. Here, 35 eyes of 35 patients were treated with low-temperature plasma ablation (coblation). All surgeries were performed by the same doctor (X.H.). The coblation went back and forth over the entire erosion area around five times for about five minutes. After the operation, patients were scheduled for follow-up visits at the outpatient clinic after 1 month, 3 months, 6 months, and 12 months, and at the end of the trial. During every visit, each patient underwent an evaluation of their ocular symptoms utilizing the following: pain score, intraocular pressure, slit lamp biomicroscopic examination, dry eye analysis, corneal topography, and corneal in vivo confocal microscopy (IVCM). Results: The mean follow-up time was 12.4 ± 6.1 months, ranging from 6 to 29 months. Of the 35 patients who had low-temperature plasma ablation, 32 eyes (91.43%) were completely symptom-free and three (8.57%) eyes had repeated episodes of recurrent corneal erosions after the surgery, at 3, 10, and 12 months, respectively. The typical RCE morphologic abnormalities observed in IVCM included the deformation and relaxation of the corneal epithelium, disorganized stromal fibers, reduced nerve fiber density, and disordered organization. After low-temperature plasma ablation, the loose cysts disappeared, and the epithelium became solid and tight. There was no obvious difference in the intraocular pressure (p = 0.090) or corneal astigmatism (p = 0.175) before and after treatment. The mean pain score decreased significantly, with a preoperative score of 7.7 ± 2.4 and postoperative score of 1.1 ± 1.8 (p < 0.001). The mean corneal thickness decreased from 562.6 ± 42.2 mm to 549.6 ± 26.9 mm (p = 0.031). The mean non-invasive keratograph tear meniscus height (NIKTMH) decreased from 0.210 ± 0.054 mm to 0.208 ± 0.045 mm (p = 0.001), and the mean TBUT decreased from 6.191 ± 2.811 s to 5.815 ± 2.802 s (p < 0.001), which manifested as a slight worsening of dry eyes. In one case, the patient’s corneal astigmatism became more severe, which may be related to the high instantaneous energy when the operation did not flush in a timely manner, and it was recovered after 6 months. Conclusions: Low-temperature plasma ablation is an effective and safe procedure to treat patients with recurrent corneal erosions.

Interventions for recurrent corneal erosions

BACKGROUND

Recurrent corneal erosion is a common cause of disabling ocular symptoms and predisposes the cornea to infection. It may follow corneal trauma. Measures to prevent the development of recurrent corneal erosion following corneal trauma have not been firmly established. Once recurrent corneal erosion develops, simple medical therapy (standard treatment) may lead to resolution of the episode. However, some people continue to suffer when such therapy fails and repeated episodes of erosion develop. A number of treatment and prophylactic options are then available but there is no agreement as to the best option. This review version is an update to the original version published in 2007 and a previous update published in 2012.

OBJECTIVES

To assess the effectiveness and adverse effects of regimens for the prophylaxis of further recurrent corneal erosion episodes, the treatment of recurrent corneal erosion and prophylaxis of the development of recurrent corneal erosion following trauma.

SEARCH METHODS

We searched CENTRAL, which contains the Cochrane Eyes and Vision Trials Register; MEDLINE; Embase; LILACS; the ISRCTN registry; ClinicalTrials.gov and the ICTRP. The date of the search was 14 December 2017.

SELECTION CRITERIA

We included randomised and quasi-randomised trials that compared a prophylactic or treatment regimen with another prophylaxis/treatment or no prophylaxis/treatment for people with recurrent corneal erosion.

DATA COLLECTION AND ANALYSIS

We used standard methods expected by Cochrane. Two authors independently screened search results, extracted data and assessed risk of bias in the included studies using the Cochrane tool for assessing risk of bias. We considered the following outcome measures: resolution of symptoms after treatment; recurrence after complete or partial resolution; symptoms (pain); adverse effects (corneal haze, astigmatism). We graded the certainty of the evidence using GRADE for the three most clinically relevant comparisons.

MAIN RESULTS

We included eight randomised and two quasi-randomised controlled trials in the review, encompassing 505 participants. Seven studies were from Europe (Germany, Sweden and the UK), two from East Asia (Hong Kong and Japan) and one from Australia. Nine of the studies examined treatments for episodes of recurrent corneal erosions and one study considered prophylaxis to prevent development of recurrent corneal erosions after injury. Two of the nine treatment studies also enrolled participants in a study of prophylaxis to prevent further episodes of recurrent corneal erosions. The studies were poorly reported; we judged only one study low risk of bias on all domains.Two studies compared therapeutic contact lens with topical lubrication but one of these studies was published over 30 years ago and used a therapeutic contact lens that is no longer in common use. The more recent study was a two-centre UK study with 29 participants. It provided low-certainty evidence on resolution of symptoms after treatment with similar number of participants in both groups experiencing resolution of symptoms at four months (risk ratio (RR) 0.97, 95% confidence interval (CI) 0.62 to 1.53). There was very low-certainty evidence on recurrence after partial or total resolution at seven months' follow-up (RR 1.07, 95% CI 0.07 to 15.54). There was no evidence of an important difference in pain score (score of 3 in the contact lens group and score of 2 in the topical lubrication group, low-certainty evidence) and no adverse effects were reported. The older study, using a contact lens no longer in common use, found an increased risk of pain and complications with the contact lens compared with hypromellose drops and paraffin ointment at night.A single-centre, Australian study, with 33 participants, provided low-certainty evidence of an increased risk of recurrence with phototherapeutic keratectomy compared with alcohol delamination but with wide confidence intervals, compatible with increased or decreased risk (RR 1.27, 95% CI 0.48 to 3.37). Time to recurrence was similar in both groups (6.5 and 6 months, low-certainty evidence). On average people receiving phototherapeutic keratectomy reported less pain but confidence intervals included no difference or greater pain (mean difference (MD) -0.70, 95% CI -2.23 to 0.83, low-certainty evidence). No adverse effects were reported.A 48-participant study in Hong Kong found recurrences were less common in people given diamond burr superficial keratectomy after epithelial debridement compared with sham diamond burr treatment after epithelial debridement (RR 0.07, 95% CI 0.01 to 0.50, moderate-certainty evidence). The study did not report pain scores but adverse effects such as corneal haze (RR 0.92, 95% CI 0.06 to 13.87, low-certainty evidence) and astigmatism (0.88 versus 0.44 dioptres, moderate-certainty evidence) were similar between the groups.A study comparing transepithelial versus subepithelial excimer laser ablation in 100 people found low-certainty evidence of a small increased risk of recurrence of corneal erosion at one-year follow-up in people given the transepithelial compared with subepithelial technique, however, the confidence intervals were wide and compatible with increased or decreased risk (RR 1.20, 95% CI 0.58 to 2.48, low-certainty evidence). Other outcomes were not reported.Other treatment comparisons included in this review were only addressed by studies published two decades or more ago. The results of these studies were inconclusive: excimer laser ablation (after epithelial debridement) versus no excimer laser ablation (after epithelial debridement), epithelial debridement versus anterior stromal puncture, anterior stromal puncture versus therapeutic contact lens, oral oxytetracycline and topical prednisolone (in addition to 'standard therapy') versus oral oxytetracycline (in addition to 'standard therapy') versus 'standard therapy'.

AUTHORS' CONCLUSIONS

Well-designed, masked, randomised controlled trials using standardised methods are needed to establish the benefits of new and existing prophylactic and treatment regimes for recurrent corneal erosion. Studies included in this review have been of insufficient size and quality to provide firm evidence to inform the development of management guidelines. International consensus is also needed to progress research efforts towards evaluation of the major effective treatments for recurrent corneal erosions.

Interventions for recurrent corneal erosions

BACKGROUND

Recurrent corneal erosion is a common cause of disabling ocular symptoms and predisposes the cornea to infection. It may follow corneal trauma. Measures to prevent the development of recurrent corneal erosion following corneal trauma have not been firmly established. Once recurrent corneal erosion develops simple medical therapy (standard treatment) may lead to resolution of the episode. However, some patients continue to suffer when such therapy fails and once resolved further episodes of recurrent erosion may occur. A number of treatment and prophylactic options are then available but there is no agreement as to the best option.

OBJECTIVES

To assess the effectiveness and safety of prophylactic and treatment regimens for recurrent corneal erosion.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 6), MEDLINE (January 1946 to June 2012), EMBASE (January 1980 to June 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to June 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 13 June 2012. We also contacted researchers in the field.

SELECTION CRITERIA

We included randomised and quasi-randomised trials that compared a prophylactic or treatment regimen with another prophylaxis/treatment or no prophylaxis/treatment for patients with recurrent corneal erosion.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed trial quality. We contacted study authors for additional information.

MAIN RESULTS

Seven randomised and one quasi-randomised controlled trial were included in the review. The trials were heterogenous and of poor quality. Safety data presented were incomplete. For the treatment of recurrent corneal erosion, a single-centre trial in the UK with 30 participants showed that oral tetracycline 250 mg twice daily for 12 weeks or topical prednisolone 0.5% four times daily for one week, or both, in addition to standard treatment, accelerated healing rates and improved symptoms. A single-centre trial in Sweden with 56 participants showed that excimer laser ablation in addition to mechanical debridement may reduce the number of erosions and improve symptoms. Furthermore, in a single-centre trial in Germany with 100 participants, transepithelial technique for excimer laser ablation had the same efficacy as the traditional subepithelial excimer laser technique but caused less pain. In a small study of 24 participants in UK, therapeutic contact lens wear was inferior to lubricant drops and ointment in abolishing the symptoms of recurrent corneal erosion and had a high complication rate, although the contact lenses used were the older generation with low oxygen permeability. A recent study in Hong Kong with 48 participants found diamond burr polishing to reduce episodes of recurrent corneal erosion. For prophylaxis of further episodes of recurrent corneal erosion, there was no difference in the occurrence of objective signs of recurrent erosion between hypertonic saline ointment versus tetracycline ointment or lubricating ointment in a small Japanese study with 26 participants. Also, in a single-centre study in the UK with 117 participants, there was no difference in symptom improvement between hypertonic saline versus paraffin ointment when used for prophylaxis. In a UK study with 42 participants, lubricating ointment at night in addition to standard treatment to prevent recurrence following traumatic corneal abrasion (erosion) caused by fingernail injury led to increased symptoms of recurrent corneal erosion compared to standard therapy alone.

AUTHORS' CONCLUSIONS

Well-designed, masked, randomised controlled trials using standardised methods are needed to establish the benefits of new and existing prophylactic and treatment regimes for recurrent corneal erosion. International consensus is also needed to progress research efforts towards evaluation of the major effective treatments for recurrent corneal erosions.