Eye surgery
Eyelid mass removal
Tumors of the third eyelid
Third eyelids are most often removed due to tumor involvement (usually SCC). See youtube video. Block the auricopalpebral nerve and supraorbital nerve. Apply topical proparicane or lidocaine. Use mosquito hemostats to lift the third eyelid up and extend it laterally. Inject local anesthesia in the dorsal and ventral margins of the base of the third eyelid. Once the block is in place, you can easily manipulate the third eyelid. You need to remove as much of the third eyelid as possible. Place two curved forceps across the dorsal and ventral margins, beyond the T shaped cartilage. Cut along the forceps with Mayo scissors. Leave the forceps in place for 1-3 minutes to provide hemostasis. Allow the surgery site to heal by second intention. NSAID administration is needed for 3-5 days and a topical antibiotic can be placed in the eye twice daily for 5 days.
As a side note, the presence or absence of third eyelids should be noted as part of prepurchase examinations.
Tumors of the lower eyelid
Smaller lower lid masses (generally SCC) may be removed using H-plasty. Because it is crucial maintain or recreate the eyelid margin, this level of reconstruction is required. n H-plasty procedure pulls up skin from lower on the face to create the margin. General anesthesia and careful incisional planning is needed. It is really cool and works in all species.
Tumors of the upper eyelid
Larger eyelid tumors including equine periocular sarcoids are generally not removable because removing them would leave a huge gap that could not be closed without excessive tension. Exposure keratitis would be highly likely due to the sutures or scar tissue pulling on the eyelid margin.
We treat the sarcoids and similar tumors with imiquimod, cisplatin beads and/or other chemotherapeutic injections. Combination therapy can be useful. Generally these need an ophthalmologist if surgery (other than enucleation) is requested.
Resources
D Brooks, Removal of the third eyelid. 2005 Clinicians Brief
B Welker et al. Excision of Neoplasms of the Bovine Lower Eyelid by H-Blepharoplasty. Veterinary Surgery, 20, 2, 133-139, 1991