**5. Follow-up schedule**

70 Keratoplasties – Surgical Techniques and Complications

Fig. 19. Eight separate radial sutures are tied and Burried in the donor button.

Fig. 20. Suturing the donor button in the recipient bed is completed using combined

Interrupted and continuous sutures.

.

The eye is examined on the first postoperative day and after a week. In these visits special attention is focused on the corneal epithelium. Usually a bandage soft lens and nonpreserved lubricant drops are used to improve reepithelialization of the cornea. Topical steroids and antibiotics are started on the first postoperative day. Topical antibiotics are discontinued after the epithelium heals completely. Topical steroids are tapered off over a 4 month period. The patient visits at monthly intervals for 4 months. During this period, every loose suture must be removed and replaced by a new suture. Adjustment of the tension of the continuous sutures can be performed during this period. After the fourth month the patient is examined every 2 months. At the 6-month postoperative visit and beyond the corneal sutures are selectively removed to improve visual function. I routinely remove sutures with the guide of retinoscopy alone and rarely a topographic corneal image is needed to determine the suture that requires removal. I remove the continuous suture if the spherical equivalent is over +3 and remove radial sutures along the steepest corneal meridian (the most "with movement" of the light reflex intercept while performing retinoscopy).

### **6. Complications**

#### **6.1 Perforation of the DM**

Perforation of the DM can occur during trephination. In this instance the wound must be sutured and the operation is better postponed to a time after the wound has healed for planned pre-Descemet level DALK.

Perforation can also occur after penetration by the tip of the needle for air injection, in which case air immediately enters the anterior chamber. No attempt to expose the bare DM should be made. However, a pre-Descemet DALK could be performed in these cases.

When the large-bubble or expanding-bubble technique is used, perforation of the DM may occur after the DM—stroma interface is overfilled. A horizontal radial tear appears at the center of the DM along the 3-to-9 o'clock meridian. It is wise to convert these surgeries to penetrating keratoplasty because trying to oppose the DM to the posterior surface of the donor cornea using gas tamponade is difficult. Even if this procedure is successfully performed, it is associated with opacification and scar formation over an elliptical area (fishmouth shape) in the posterior corneal surface that is devoid of DM. The opacification has adverse visual effects because it is centrally located.

Perforation of the DM can occur during lamellar dissection and tissue removal. In these cases a pre-Descemet DALK can be performed. The perforation site must be left until the end of tissue removal and a small amount of stromal tissue must be left over the perforation site to seal the perforation.

If an instrument touches the bare DM, perforation is possible. In most of these cases the procedure can be continued by thoroughly washing any retained viscoelastic material, suturing the donor tissue in place, and using air for intracameral injection to seal the perforation. Because the dome-shaped contour of the cornea is reduced, especially with tight sutures, the air bubble in the anterior chamber will apply noticeable pressure over the pupil to induce papillary block. Performing a peripheral iridotomy via a paracentesis is necessary and infusion of a hyperosmotic solution such as 20% mannitol is necessary to induce vitreous shrinkage if not contraindicated according to the patient's general status.

Manual Deep Anterior Lamellar Keratoplasty 73

Fig. 22. Introducing surgical devices into the anterior chamber may be accompanied with

Management includes gentle washing of the anterior chamber for flouting red blood cells after cardinal sutures are placed using a blunt-tipped cannula and irrigating the BSS through the paracentesis wound and depressing the posterior lip of the wound to drain the blood. Introducing any instrument into the anterior chamber may violate the peripheral DM

This rare condition results from proliferation of the epithelial cells in the interface. Management includes removing donor tissue, scrapping and irrigating the recipient's bed,

Peripheral wound infection is accompanied by edema, infiltration, loosening of sutures, and occasionally melting of the cornea. The loose sutures must be removed and placed in culture media along with suitable specimens for recognition of the etiologic organism. The treatment is similar to that for an infectious corneal ulcer. Fungal elements may cause deep ulcers without surface involvement. However, involvement of the donor—recipient interface with an infectious process requires donor tissue removal, vigorous treatment of the

Stromal allograft rejection may occur after successful DALK surgeries and can be accompanied by segmental corneal edema and thickening and corneal stromal

hyphema.

and turn the condition into a major complication.

recipient's bed, and a new graft (Thomas & Purnell, 1965).

**6.8 Allograft stromal and epithelial rejection** 

**6.6 Corneal intrastromal cyst**

and performing a new graft.

vascularization (Figure 23).

**6.7 Infectious keratitis** 

A small peripheral iridotomy will not guarantee that the patient will not experience a relative papillary block if the air bubble is so large or if expanding gas such as SF6or C3F8 is used.
