Question 1: Which layer of the cornea is preserved in Deep Anterior Lamellar Keratoplasty (DALK)?
A) Descemet’s membrane
B) Bowman’s layer
C) Epithelium
D) Stromal layer
Answer: A) Descemet’s membrane
Deep Anterior Lamellar Keratoplasty (DALK) is a surgical procedure used for the treatment of corneal diseases, such as keratoconus, where only the outer layers of the cornea are replaced while preserving the patient’s own Descemet’s membrane and endothelium.
Anwar, M., & Teichmann, K. D. (2002). Deep lamellar keratoplasty: surgical techniques for anterior lamellar keratoplasty with and without baring of Descemet’s membrane. Cornea, 21(4), 374-383.
Question 2: What is the main advantage of Deep Anterior Lamellar Keratoplasty (DALK) compared to Penetrating Keratoplasty (PKP)?
A) Lower risk of graft rejection
B) Faster visual recovery
C) Lower risk of intraocular pressure (IOP) elevation
D) Less postoperative astigmatism
Answer: A) Lower risk of graft rejection
Deep Anterior Lamellar Keratoplasty (DALK) is a corneal transplant procedure that preserves the patient’s own Descemet’s membrane, which reduces the risk of graft rejection compared to Penetrating Keratoplasty (PKP) where the entire cornea is replaced.
Karimian F, Feizi S. Deep anterior lamellar keratoplasty: indications, surgical techniques and complications. Middle East Afr J Ophthalmol. 2010 Jan;17(1):28-37. doi: 10.4103/0974-9233.61214. PMID: 20543934; PMCID: PMC2880371.
Question 3: What is the purpose of creating a “big bubble” in the deep anterior lamellar keratoplasty (DALK) procedure?
A) To separate the corneal stroma from Descemet’s membrane
B) To inject air into the anterior chamber for better visualization
C) To create a space for the donor corneal graft
D) To achieve hemostasis and prevent bleeding
Answer: A) To separate the corneal stroma from Descemet’s membrane
In DALK, the “big bubble” technique involves injecting air or another gas into the corneal stroma to create a large air-filled space, separating the corneal stroma from Descemet’s membrane. This allows for the removal of the diseased or damaged corneal stroma while preserving Descemet’s membrane and endothelium. Creating the big bubble helps in achieving a clear plane of dissection and ensures that only the intended corneal layer is removed, reducing the risk of complications and improving surgical outcomes.
Anwar, M., & Teichmann, K. D. (2002). Deep lamellar keratoplasty: surgical techniques for anterior lamellar keratoplasty with and without baring of Descemet’s membrane. Cornea, 21(4), 374-383.