Many ulcers in general practice can be successfully managed medically, and in some cases additionally with a temporary tarsorrhaphy or a third eyelid flap. However for deeper ulcer where perforation threatens then there is an indication for placing a graft to support the cornea.

This may be mechanical support or it may be for nutritive support. If the cornea has a deficit greater than 50% of its thickness then a mechanical support should be considered. A nutritive support graft usually does also increase mechanical support but is primarily used to deliver a blood supply to the cornea.

Conjunctival Grafts
In all grafts that are directly sutured to the cornea (Acell, Conjunctival pedicle and corneoconjunctival) the cornea to which it is sutured needs to be stable and non infected. The deficit may need to be enlarged by the trimming back to the healthy tissue required for suture retention. A 360 degree graft may be placed over unstable and infected tissue if required as it is sutured to itself. Infected/ melting corneas can be managed surgically by resection of the infected area and graft placement.

Sutures used in the cornea should be 8/0 or smaller and magnification should be used to improve technique. The conjunctival portion of any graft should be thinned as much as possible by removing the sub tenons layer (white layer under the conjunctiva). This layer contains contractile elements which will pull the graft off if not removed. The graft should be under no tension at the time of suturing so that the unsutured graft will sit in the defect without retracting. It is harder to prepare a graft in a flaccid eye so we usually take the graft (having assessed the size required) before addressing the cornea itself if the defect is at risk of perforation. Ideally the base of the graft should be either dorsal or ventral so that the eyelids run with the graft, rather than across it, when blinking.

Always be generous in the assessment of graft size required. Conjunctival grafts can be trimmed smaller if required but it is really annoying when they are too small and that is hard to rectify. We can be contacted on the VETLINE 9572 1966 at any time if you have a nasty cornea.

Further Information for Vets