DALK preferred over PK, DSEK for keratoconus and secondary ectasia:
A zigzag incision made with a femtosecond laser provides a strong and stable interface between the lamellar graft and recipient cornea, surgeon says.
Lamellar transplantation is the preferred transplant method for most patients with keratoconus or post-LASIK corneal ectasia, told be surgeons.
Complex incision designs generated with femtosecond lasers, such as the zigzag, enhance the safety and accuracy of deep anterior lamellar keratoplasty (DALK) performed on thin corneas.
DALK is preferable to PK because it enables the surgeon to preserve the corneal endothelium and reduce the risk of graft rejection. Patients who undergo PK also face an increased risk of IOP spikes and delayed healing attributed to corticosteroids used to prevent graft rejection.
PK has a high graft failure rate, even in eyes with keratoconus.
DALK is an invasive treatment for ectasia. It’s recommended less invasive treatments such as rigid gas-permeable contact lenses, intracorneal rings and corneal cross-linking, unless the patient cannot wear contact lenses, has central corneal thickness of less than 300 µm or has significant corneal scarring.
Side cuts, lamellar dissection:
Femtosecond lasers are suited for performing side cuts, not lamellar dissection.
Three technique options for lamellar dissection include hand dissection, the big bubble technique and the peeling technique.
Manual trephination is the standard of care but still has a few disadvantages.
Disadvantages of manual trephination also include the difficulty of cutting at a 90º angle at the desired depth when doing a hand dissection, Dr. Price said.
The zigzag incision is more accurate than a manual incision in terms of wound shape and depth.
A zigzag incision placed within 70 µm of Descemet’s membrane minimizes air escape into the periphery of the cornea in cases in which the big bubble technique is used, and it helps the surgeon gauge the depth when using a hand dissection technique.
Optical Coherence Tomography is a noninvasive imaging technology used to obtain high resolution cross-sectional images of the retina. The layers within the retina can be differentiated and retinal thickness can be measured to aid in the early detection and diagnosis of retinal diseases and conditions.
OCT testing has become a standard of care for the assessment and treatment of most retinal conditions. OCT uses rays of light to measure retinal thickness. No radiation or X-rays are used in this test, an OCT scan does not hurt and it is not uncomfortable.
img-29img-30img-31You may be given an OCT scan for a variety of reasons, including monitoring of the progress of your disease, verifying or discounting suspected swelling of the retina or checking OCT results against other results to determine the effectiveness of the current medication regime.
Optical Coherence Tomography uses technology that is best compared to ultrasound, except that it employs light rather than sound and thereby achieves clearer, sharper resolutionThe zigzag incision has an interlocking tongue-and-groove wound configuration that seals the interface between the lamellar graft and recipient cornea. In addition, the interlocking wound edges improve the match between a thicker graft and a thinner recipient cornea compared with manual incisions.
Additionally, a laser-cut incision allows a surgeon to perform deep dissection without a big bubble more easily.
About Dr V Praneeth (MBBS DNB FAEH) Medical Director, Consultant Cornea, Cataract & Refractive surgeon Dr. Praneeth Vaddadi completed his basic medical education from Kakatiya Medical College, Warangal. He then