Posterior lamellar keratoplasty procedures were performed in a series of 21 patients, after an Institutional Review Board-approved informed consent was obtained from each patient (Figure 4.1).

Figure 4.1: Diagrammatic representation of the posterior lamellar keratoplasty procedure. After dissection of a stromal pocket through a scleral incision, a posterior lamellar disc is trephinated from the donor cornea. In the recipient cornea, a stromal pocket is made and a flat trephine is inserted herein to excise a posterior disc. The donor disc is implanted into the recipient opening, and the scleral wound is sutured.

Through a paracentesis, the anterior chamber was completely filled with air. The superior conjunctiva was opened, and a 9.0 mm partial thickness scleral incision was made. With the spatula, a stromal pocket was dissected across the cornea at 80% stromal depth, using the air-to-endothelium interface as a reference plane for dissection depth (see Chapter 2; Figure 2a-c, 3a and 3b).

Figure 4.2: Demonstration of the lamellar dissection technique in a human eye bank eye. (a) The anterior chamber has been filled with air. In between the blade tip and the air-to-endothelial interface light-reflex, a dark band is visible. (b) Because the dark band reflects unincised posterior corneal tissue, the dark band decreases in width when the blade is advanced into the deeper stromal layers. (c) When the blade appears to touch the air-to-endothelium interface, a stromal dissection level just anterior to the posterior corneal surface is reached.

A custom made, 7.0 or 7.5 mm diameter, flat trephine (D.O.R.C. International, Zuidland, NL) was inserted into the pocket, to excise a posterior lamellar disc (Figure 3c). After perforation, remaining posterior corneal tissue was cut with custom made microscissors (D.O.R.C. International, Zuidland, NL) (Figure 3d), and the excised, recipient posterior disc was removed from the eye with fine forceps (Figure 3e).

Figure 4.3: Drawings of the posterior lamellar keratoplasty procedure. (a) Using the optical effects of the air bubble in the anterior chamber, the dissection is started at approximately 80% corneal depth, and (b) extended across the cornea. (c) A posterior corneal trephine is inserted into the pocket to excise a posterior lamellar disc. (d) After remaining stromal attachments are cut with microscissors, (e) the posterior disc is removed from the recipient cornea. (f) On a glide, the donor posterior disc is inserted into the stromal pocket, and (g) the spoon is withdrawn after positioning of the donor tissue. (h) The scleral incision is sutured, and the anterior chamber is filled with air to push the donor posterior disc against the anterior recipient cornea.

The spoon-shaped glide carrying the donor posterior disc was introduced into the recipient stromal pocket (Figure 3f), and the same-size disc was slid into the recipient posterior opening (Figure 3g). The scleral incision was closed with 10-0 monofilament nylon sutures (Alcon, Gorinchem, NL) (Figure 3h).

Figure 4.5: Slit-lamp photographs of the same eye one day and two weeks after posterior lamellar keratoplasty. The posterior transplant, 7.5 mm in diameter, is in position with complete apposition of the donor-to-host tissues at the stromal interface. The visual acuity was 0.8 at 6 months, and 1.0 at one year.

Figure 4.6: Slit-lamp photographs of the same eye two years after posterior lamellar keratoplasty. The posterior transplant, 7.0 mm in diameter, is in position with complete apposition of the donor-to-host tissues at the stromal interface. The visual acuity is 0.25 (Divergent strabismus with amblyopia).