What is Deep Anterior Lamellar Keratoplasty (DALK)?
Deep Anterior Lamellar Keratoplasty (DALK) is an advanced surgical technique used to treat corneal diseases affecting the anterior layers of the cornea. Unlike traditional full-thickness corneal transplants, DALK preserves the healthy endothelial layer, making it an attractive option for patients with specific corneal conditions. This procedure can restore vision and improve the quality of life for individuals suffering from corneal opacities, keratoconus, and other anterior corneal pathologies.
Indications
DALK is indicated for patients with:
- Keratoconus: A condition characterized by the thinning and bulging of the cornea, leading to distorted vision.
- Corneal Scarring: Scarring due to infections, injuries, or previous surgeries that affect the front layers of the cornea.
- Corneal Dystrophies: Genetic disorders that lead to the deterioration of corneal tissue, such as granular or lattice dystrophy.
- Corneal Ectasia: Thinning of the cornea that may occur after refractive surgeries like LASIK.
The procedure is typically considered when the patient’s vision cannot be corrected with glasses or contact lenses and when the endothelial layer remains healthy.
Diagnosis
The diagnosis leading to a recommendation for DALK involves a thorough ophthalmic examination, including:
- Slit-Lamp Examination: Allows the ophthalmologist to assess the cornea’s structure, identify opacities, and evaluate the depth of the corneal issue.
- Topography: This imaging technique provides detailed maps of the cornea’s surface, helping to identify irregularities and the extent of thinning.
- Pachymetry: Measurement of corneal thickness to assess the suitability of the cornea for DALK.
- Visual Acuity Tests: Determines the level of vision impairment and the impact on daily activities.
Procedure
Preoperative Preparation
Prior to surgery, patients undergo a comprehensive evaluation, including discussions about the procedure, risks, benefits, and expected outcomes. Patients may be advised to stop wearing contact lenses for a specified period to ensure accurate measurements.
Surgical Technique
Anesthesia: The procedure typically begins with local anesthesia, and sedation may be used to ensure comfort.
Corneal Dissection: The surgeon creates an incision and carefully removes the diseased anterior layers of the cornea while preserving the healthy endothelium.
Donor Tissue Preparation: A donor cornea is prepared, often using tissue from a deceased donor, which has been screened for safety.
Grafting: The prepared donor tissue is inserted and aligned with the patient’s existing cornea. The graft is secured using sutures or other fixation methods.
Closure: The incision is carefully closed, and the surgical site is protected with a bandage contact lens.
Expected Outcomes
Many patients experience significant improvements in vision following DALK. The procedure often results in reduced dependence on glasses or contact lenses and enhances overall quality of life. However, the final visual outcome can vary based on individual circumstances and the underlying condition.
Deep Anterior Lamellar Keratoplasty is a vital surgical option for patients with anterior corneal diseases. By preserving the healthy endothelium and focusing on the diseased superficial layers, DALK provides an effective solution for restoring vision while minimizing complications. As with any surgical procedure, it is essential for patients to engage in thorough discussions with their ophthalmologist to determine the best course of action for their specific condition.