DSAEK (Descemet Stripping Automated Endothelial Keratoplasty) was the procedure that transformed corneal transplantation in the 2000s — moving from full-thickness penetrating keratoplasty to a selective, partial-thickness approach replacing only the diseased endothelium. While DMEK has become the preferred endothelial transplant technique in straightforward eyes, DSAEK retains an important role in complex anatomy where DMEK is more technically demanding.
What Is DSAEK?
DSAEK is a partial-thickness corneal transplant that replaces only the diseased inner layer of the cornea — the endothelium and a thin layer of adjacent stroma — while leaving the healthy front layers of the cornea intact. It treats conditions affecting the corneal endothelium, the specialised cell layer responsible for actively pumping fluid out of the corneal tissue and maintaining corneal clarity. When endothelial cells fail, the cornea swells and becomes cloudy, causing visual impairment not correctable with glasses or contact lenses.
The technique replaced full-thickness penetrating keratoplasty as the standard treatment for endothelial disease in the early 2000s, offering faster recovery, no sutures for the graft itself, and a significantly lower risk of rejection compared with PKP. DSAEK in turn gave way to DMEK as the preferred technique in most cases as surgeon experience accumulated — but DSAEK remains the appropriate choice in a defined group of patients where eye anatomy makes DMEK technically unpredictable.
When Is DSAEK Used?
DSAEK is indicated for conditions that damage or destroy the corneal endothelium, including Fuchs endothelial dystrophy — the most common indication — and bullous keratopathy, which is persistent corneal swelling that can develop after cataract surgery, intraocular inflammation, or other insults to the endothelium.
DSAEK may be preferred over DMEK in eyes where the anatomy makes DMEK technically more demanding — including eyes with iris defects, previous vitrectomy, silicone oil in the eye, or significant anterior segment abnormalities. In these complex situations, DSAEK's thicker graft is more predictable to position and has a lower rate of graft detachment, making it the surgeon's preferred choice when eye anatomy is not straightforward.
Standard DSAEK vs Ultrathin DSAEK
DSAEK grafts vary considerably in thickness, and this affects both visual outcomes and the speed of visual recovery. Standard grafts are robust and technically predictable; ultrathin grafts produce better visual outcomes but require more precise tissue preparation.
Standard DSAEK grafts are typically 100–150 microns in thickness. They are robust and straightforward to handle and insert, with a well-established safety record accumulated over two decades of surgical experience. Most patients achieve good visual outcomes, though the additional tissue at the interface between donor and recipient cornea can limit best corrected visual acuity compared with thinner techniques.
Ultrathin DSAEK uses grafts of less than 100 microns — often 50–70 microns — prepared either by manual dissection or using a microkeratome to produce a consistently thin and regular lamella. The thinner graft reduces interface haze and achieves visual outcomes closer to DMEK, while retaining the handling advantages of DSAEK over the more technically demanding DMEK procedure. Ultrathin DSAEK is particularly useful in complex eyes where DMEK carries higher risk, as it allows the surgeon to achieve near-DMEK visual quality without the additional surgical difficulty of DMEK tissue unfolding and positioning.
The choice between standard and ultrathin DSAEK depends on the individual eye's anatomy, the available donor tissue, and surgical judgment at the time of the procedure.
The DSAEK Procedure
DSAEK is performed as a day procedure under local or general anaesthesia. A small incision of approximately 4–5mm is made at the peripheral cornea. The diseased endothelium and Descemet membrane are stripped from the recipient cornea using specialised instruments, and the donor tissue — pre-cut to the appropriate thickness by an eye bank or by the surgeon — is folded and inserted through the incision into the anterior chamber.
The graft is then unfolded and positioned against the back surface of the recipient cornea. An air bubble is injected beneath the graft to press it against the cornea and hold it in position while the natural endothelial pump begins to dehydrate the graft and encourage adhesion. The patient is asked to lie face-up for a period after surgery to maintain the air bubble in contact with the graft. The incision is closed with sutures, which are removed at a later visit.
Recovery After DSAEK
Visual recovery after DSAEK is faster than after full-thickness PKP but somewhat slower than after DMEK, due to the additional tissue thickness at the graft-recipient interface. Most patients notice meaningful visual improvement within two to four weeks, with best corrected vision typically achieved within three to six months.
A proportion of grafts — approximately 10–15% — may partially detach in the early post-operative period, requiring a rebubbling procedure in which additional air is injected to reattach the graft. This is a straightforward procedure performed in the consulting room or operating theatre. Graft failure requiring regrafting occurs in a small minority of cases and can be managed with a repeat DSAEK or DMEK procedure.
DSAEK vs DMEK — How to Choose
Both DSAEK and DMEK replace the diseased endothelium, but they differ in graft thickness, technical complexity, and typical visual outcomes. In straightforward anatomy, DMEK is generally preferred. In complex eyes, DSAEK — particularly ultrathin DSAEK — is the more appropriate choice.
DMEK uses only the endothelial monolayer and Descemet membrane — approximately 10–15 microns — giving the fastest visual recovery and the best long-term visual acuity, but it is technically more demanding and has a higher rate of graft detachment requiring rebubbling. DSAEK — particularly ultrathin DSAEK — achieves visual outcomes that approach those of DMEK while being more predictable in complex anatomy. Where the anterior stroma is also diseased, DALK or full-thickness PKP may be required.
The decision between techniques is made at the pre-operative assessment based on individual eye anatomy, the patient's ocular history, and surgical judgment.
Dr Ross MacIntyre BA (Chemistry) MD FRANZCO is a cataract, corneal and refractive surgeon practising in Melbourne. He completed subspecialty fellowship training in cornea, complex cataract and refractive surgery at the Wilmer Eye Institute, Johns Hopkins University, and holds a public appointment at the Royal Victorian Eye and Ear Hospital. Dr MacIntyre is the author of Seeing Clearly: Your Complete Guide to Cataract Surgery and Modern Lens Options (available on Amazon), a plain-language guide to cataract surgery for patients and their families.