Manual Debridement Vs Phototherapeutic Keratectomy in the Treatment of Corneal Basement Membrane Dystrophy

Centre hospitalier de l'Université de Montréal (CHUM)

Status: Not yet enrolling

Conditions: Epithelial Basement Membrane Dystrophy

Treatments: Procedure: Manual debridement; Procedure: Phototherapeutic keratectomy

Study type: Interventional

Funder types: Other

Identifiers

NCT06618508

2024-12106

Details and patient eligibility

About

Of the few comparisons made in the existing literature, the results of PTK are comparable to those documented for manual debridement (MD). However, the shorter length of follow-up in patients with MD may have underestimated the associated complications. Our study, therefore, aims to offer a comparison between these two techniques to clarify the choice of effective treatment with a good safety profile.

Full description

Epithelial Basement Membrane Dystrophy (EBMD) affects the anterior cornea, impacting about 2% of the population. EBMD is characterized by alterations and duplications of the basement membrane, a tissue layer that connects the epithelium to the underlying eye tissue. Dysfunction of the basement membrane prevents proper adhesion of the overlying epithelium, leading to recurrent corneal erosions. Additionally, tissue protrusions infiltrate the epithelium, creating surface irregularities that cause symptoms like blurred vision and irregular corneal topographies. This abnormal proliferation results in microcysts and corneal irregularities resembling fingerprints and maps. These surface irregularities can be observed in optical coherence tomography (OCT) images showing epithelial thickening. Non-invasive medical treatments are the first line of therapy, including lubricating drops and hypertonic solutions to protect the ocular surface and promote epithelial adhesion. For corneal erosions, soft contact lenses are used to aid healing. Surgical interventions such as manual debridement and phototherapeutic keratectomy (PTK) are required in refractory cases. These are also indicated for patients preparing for cataract surgery to optimize preoperative corneal measurements and postoperative optical outcomes. Manual debridement (MD), a technique since 1952, involves scraping off the irregular epithelium to allow a new layer to form. Some surgeons use 20% ethanol on the cornea before scraping with a blade or sponge, preserving the basement membrane. This method is simple, cost-effective, and has an 85% success rate in treating recurrent corneal erosions. However, recurrence rates are up to 24%, with the first recurrence typically within six months. Corneal opacities can form between 7 and 41 days post-procedure. Over the past two decades, PTK has become increasingly used for anterior corneal pathologies, including EBMD. PTK uses a 193nm excimer laser to break molecular bonds between cells on the epithelial surface. It is considered a more reliable, safe, and precise alternative to manual debridement, completely obliterating the basement membrane and potentially reducing recurrence rates. Success rates without recurrence range from 46% to 100%, with minimal complications. Unlike manual debridement, PTK may induce a hyperopic shift, which stabilizes within a year. Corneal erosions and pain recur at about 13% over an average of 9.7 months. Comparative studies between these two methods are scarce, and more data is needed to favor one technique over the other. Limited comparisons suggest PTK results are comparable to manual debridement, though shorter follow-ups in MD patients may underestimate associated complications. Our study aims to compare these techniques to describe the efficacy and safety of both treatments.

Enrollment: 25 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patient over 18 years of age;
• Ability to give free and informed consent
• At least 1-year follow-up possible
• Patients with bilateral basal membrane corneal dystrophy who are symptomatic (recurrent corneal erosions, visual disturbances) and are candidates for bilateral surgery.

Exclusion criteria

• Patient under 18 years of age;
• History of ocular infection with herpes simplex virus.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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25 participants in 2 patient groups

Manual debridement

Active Comparator group

Description:

Manual debridement is a technique that has existed since 1952 and whose objective is to remove the irregular epithelium by scraping with an instrument, thus allowing the formation of a new superficial layer. Some surgeons use 20% ethanol which they apply to the cornea to debride it before using a blade or sponge to complete the procedure. In this technique, the basement membrane is preserved. This method is still used being simple and cost effective. Its effectiveness in the treatment of recurrent corneal erosions is demonstrated by a success rate estimated at 85%. Thus, it is one of the methods of treating epithelial basement membrane dystrophy. However, the recurrence rate associated with manual debridement is up to 24%, and the average duration before a first recurrence is estimated at 6 months. The formation of corneal opacities was recorded between 7 and 41 days following the intervention.

Treatment:

Procedure: Manual debridement

Phototherapeutic keratectomy

Experimental group

Description:

Over the past two decades, phototherapeutic keratectomy (PTK) has become an increasingly used approach for the treatment of several anterior corneal pathologies, including epithelial basement membrane dystrophy. This technique consists of directing a 193nm excimer laser towards the epithelial surface in order to break the molecular bonds between cells. PTK appears to be a more reliable, safe and precise alternative to manual debridement. Unlike manual debridement, PTK completely obliterates the basement membrane which would promote a reduction in the recurrence rate according to some experts. Thus, the success rate without recurrence has been estimated between 46 to 100% by certain studies and the associated complications are minimal.

Treatment:

Procedure: Phototherapeutic keratectomy