Ocular Surface Restoration

The process of ocular surface restoration is as follows:

• Implantation of amniotic membranes, limbal autografts, or cultured stem cells [14].17 In the postoperative period, topical, preservative-free corticosteroids are used and a soft bandage contact lens needs to be placed.

• Lamellar keratoplasty has the advantage of sparing the patient of the risks of open globe surgery, but the development of an intracorneal (interfacial) scar is a potential complication. Deep lamellar keratoplasty may be combined with autologous limbal grafting [20].

• Penetrating keratoplasty requires epithelial regeneration from the lim-bus to prevent superficial ulceration.

- The "umbrella" technique can be used in early cases, serving tectonic as well as surface reconstruction purposes [8].

- In the "horseshoe" technique the donor tissue, containing 120° of the limbus, is eccentrically placed [18].

- Both of these are high-risk grafts and thus topical as well as systemic^ immunosuppressive therapy is required. Nevertheless, graft rejection remains common; if several grafts have been rejected, the permanent keratoprosthesis remains the last alternative.

• Permanent keratoprosthesis use is not without risk/9 but they are the best option for severely damaged eyes. The device can provide structural stability and often permit the preservation of vision. Several types are available (e.g., Osteo-Odonto-Keratoprosthesis [2], Boston keratoprosthesis [1, 15], and ACTO Tex-KPRO [7] (Figs 3.1.4, 3.1.5), and all require long-term follow-up. A specialist experienced in the field needs to be consulted.

• Additional interventions, such as cataract extraction or antiglaucoma surgery, are performed as required.

17 From the fellow eye, a patient's relative, or another donor.

18 e.g., mycophenolic acid (Myfortic; Novartis AG, Basel, Switzerland).

19 e.g., extrusion, inability to measure the IOP, endophthalmitis.

Fig. 3.1.4 Fjodorov keratoprosthesis. The device has a titan ring and a PMMA optic. A rigid retroprosthetic membrane has occurred, but a central hole still allows some vision
Fig. 3.1.5 ACTO Tex-KPRO keratoprosthesis. Implanted 8 months previously, this device allows 0.4 visual acuity; the retina is reattached under silicone oil, and the IOP is 15 mmHg

consider irrigation the most important element of the treatment use any neutral fluid for irrigation and irrigate both the visible, easily accessible areas as well as the upper fornix, and remove all agent particles mechanically admit patients with Grade III or Grade V injuries administer topical corticosteroids and antibiotics long-term to prevent infection, and to reduce inflammation and scarring surgically reconstruct the severely damaged anterior segment

delay irrigation to take a detailed history forgo the irrigation even if the injury is not fresh: it may still improve the final outcome neglect the IOP: if elevated, it can quickly make the prognosis much worse try to restore the ocular surface without first addressing lid and eyelash position abnormalities

Summary

A chemical injury is one of the very few conditions in which the prognosis may be determined literally by minutes: if the irrigation is delayed or done inappropriately, the damage can be irreversible.

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