CHAPTER 4.4

FOLLOW-UP AND POSTOPERATIVE TREATMENT OF SUPERFICIAL ANTERIOR LAMELLAR KERATOPLASTY

The result of a superficial anterior lamellar keratoplasty (SALK) will depend on the initial pathology and the surgical technique, but an adequate follow-up and post-operative treatment will create the conditions for a faster recovery, will allow to prevent and treat the complications that may arise and will contribute to improve the chances of final success.

TREATMENT

The postoperative treatment of SALK is essentially topical. Lubricants should be given frequently – at the beginning every hour –, with progressive slow reduction for months. Corticosteroids, at moderate doses according to the pathology – usually one drop every 4 hours for the first 15 days – are reduced over the following months, if necessary passing to more "soft" drugs such as fluorometholone. If a greater than usual reaction or tendency to fibrosis is observed, this treatment should be prolonged as necessary, even for more than 6 months, always controlling the intraocular pressure.

Preventively a broad-spectrum antibiotic is usually given for the first 7 to 10 days. Given that the dosages are different, and progressively reducing the doses generates resistance to antibiotics, eye drops are recommended in association with corticosteroids. Whenever the application is greater than 3 per day or if there is any alteration of the ocular surface, it is preferable that all products are without preservatives. In cases with antecedents or risk of band degeneration or other type of calcification, those containing phosphates should be avoided, either in the drug itself (dexamethasone) or in the excipients.

FOLLOW UP AND EVOLUTION

We usually conduct follow-up consultations the day after the intervention, at 3, 7, 15 days, 1, 3, 6 and 12 months, followed by annual evaluations. In the first days it is normal that a certain edema in the donor and a mild inflammatory reaction persist. The therapeutic contact lens is maintained until the epithelization is complete and the surface is regular, usually around one week (Figure 1).

If sutures are placed, their removal will depend on the technique and the surgeon, although in general in SALK it is earlier than in other types of keratoplasty. It is recommended that the traction be centrifugal, to avoid lifting the graft. We usually start after the third week – particularly if an excessively tight suture is seen – and is usually completed within the first 6 months. Some surgeons prefer to leave some sutures longer if they help control astigmatism and do not cause problems. Any suture that is loose or begins to induce infiltration or vascularization should be removed immediately, as it may cause invasion of the interface. The techniques without suture avoid all this problematic and with them better results have been described^1,2. However, sutures may be necessary in certain cases since they allow astigmatism to be controlled by selective removal.

Apart from functional and slit lamp examinations, other tests are performed such as topography and aberrometry, to assess the objective evolution of the graft. The OCT (Figure 2) allows checking its thickness and that of possible residual opacities. These measurements are more reliable after the third month. Confocal microscopy allows to assess in more detail the state of the graft and the interface (Figure 3).

The visual recovery is usually slow, something we must warn the patient about. If necessary, a provisional optical correction may be given, although the definitive one should wait for the complete removal of the sutures and in general a minimum of 6 months. The residual refractive defect can be treated by ablation with excimer laser in the bed – partially lifting the disc as in a LASIK retouching. This will also be useful to eliminate residual opacities, always respecting the residual bed thickness around 300 μm – although we do not know ectasia cases reported after this procedure in SALK carrier corneas. Correction with a permeable rigid contact lens should always be considered, since in the presence of residual irregularity, it allows notable visual improvements.