Ophthalmology Wet Lab Notes - Kimberly Hsu, DVM, MSc, DACVO If you have questions, please do not hesitate to call Dr. Hsu at Eye Care for Animals, St. Charles at 630-444-0393 or email at stcharlesinfo@eyecareforanimals.com Linear Grid Keratotomy Indications: to expedite re-epithelialization of non-healing, indolent corneal ulcers in middle-aged to older dogs Blepharostat 25G needle Fine tooth forceps (0.3mm teeth ideally) Sterile cotton tip applicator OR Kimura spatula Dilute 0.5% betadine Topical proparacaine Procedure: 0.5% betadine rinse x 2 Proparacaine x 2-3 rounds +/- sedation Cotton tip applicator or Kimura spatula debridement until no more loose epithelium can be removed (often the entire corneal surface!) 25G needle +/- bent needle tip to 90 degrees to decrease corneal penetration risk Grid pattern: lines 0.5-1mm apart, 1-2mm past corneal defect Depth: ~0.1mm Do NOT cut into cornea; gentle dragging sensation only!!! Tobramycin TID Tramadol E-collar Red and blue is good for you, yellow and green needs to be seen Hotz-Celsus Procedure Indications: to correct entropion (in-rolling) of the eyelids Eyelid plate 5-0 to 6-0 Prolene
Clip and 0.5% betadine scrub x 3 The skin and orbicularis oculi muscle layers are incised by scalpel. Use an eyelid plate under the eyelid for stability, tension, and hemostasis!!! The incision should be 2 3 mm from the margin to allow for space to suture The length and height of the crescent shaped incision are determined by the length and shape of the entropion Excision should rarely be symmetrical, often lateral > medial Extend the incision 1-2 mm past the entropic site The strip of eyelid skin and orbicularis oculi muscle are carefully dissected and excised by small tenotomy scissors. Use blunt dissection to maintain the same tissue plane. The surgical wound is apposed by 4-0 to 6-0 simple interrupted nonabsorbable sutures. The sutures should be angled somewhat to accommodate the two different lengths of the wound edges. Suture using rule of halves Proximal suture tag should be as short as possible and distal suture tag left long to facilitate suture removal When the patient is awake with topical anesthetic on board, use finger to manually evert tissue to assess how tall the excision site should be Reassess prior to make incisions under general anesthesia Also reassess correction prior to suturing in the anesthestized patient! Remove additional tissue if correction is insufficient. Fluorescein stain before discharge! Neo/Poly/Dex ointment BID- TID (No corticosteroid if ulcer present, & start topical antibiotic) Eyelid Mass 4-Sided Excision Indications: to remove eyelid masses; only if less than 1/3 of eyelid length affected! Eyelid plate 4-0 to 6-0 Vicryl 4-0 to 6-0 Prolene
Clip and 0.5% betadine scrub x 3 The eyelid neoplasm is excised by tenotomy scissors to create a four-sided defect ( house or diamond ) 0.5-1mm margins usually adequate if a benign neoplasm is suspected The wound is apposed by two layers of sutures. The tarsoconjunctiva is apposed by a 4-0 to 6-0 simple continuous or U-shaped absorbable suture. Ensure knot is buried within tarsus. The skin muscle layer is apposed by 4-0 to 6-0 simple interrupted non- absorbable sutures Consider Neo/Poly/Dex ointment BID-TID if the eyelid/conjunctiva appear inflamed prior to surgery if no corneal ulcer is present (fluorescein negative). At minimum, consider use of a thick topical lubricant BID-TID (i.e. Genteal Gel Severe, etc.). Need to avoid anesthesia? Consider referral for CO2 photoablation Consider submission for histopathology to confirm diagnosis or if suspect atypical/malignant eyelid neoplasm Figure of 8 suture to appose margin: Symmetry is important Margin apposition is critical! Fluorescein stain before discharge! Neo/Poly/Dex ointment BID- TID (No corticosteroid if ulcer present, start topical antibiotic) Redo it if needed Can use Meibomian glands to gauge distance Morgan Pocket Technique Indications: to correct prolapse of the third eyelid gland (cherry eye) Eyelid speculum 2 x Mosquito hemostats 5-0 to 6-0 Vicryl 4-0 Prolene
Clip and 0.5% betadine rinse x 3 Parallel curvilinear incisions are made dorsal and ventral to the prolapsed gland on the bulbar aspect of the TEL using a 6400 Beaver Blade / No. 15 blade and/or Steven s Tenotomy scissors Use blunt dissection with Steven s Tenotomy scissors to create a deep pocket! Gland is reduced into the pocket Tie a knot (surgeon s knot with three throws) on the palpebral surface of the TEL, then pass the suture through the TEL, allowing the needle to emerge at one end of the to the bulbar conjunctival incision initially created Pocket is closed with absorbable suture i.e. 6-0 Vicryl (simple continuous one direction followed by inverting Cushing s layer the opposite direction) Leave a 2-3mm opening on either side to allow for tear secretion Pass the needle back through to the palpebral conjunctival side of the TEL and secure suture to the original knot (4 throws) Place a medial temporary tarsorrhaphy suture using 4-0 Prolene As long as fluorescein stain negative, pre-treat prior to surgery for 1-2 weeks using Neo/Poly/Dex BID-TID Prior to the surgery, with the patient awake, under proparacaine anesthesia, look for other third eyelid abnormalities such as everted cartilage that may impact surgical correction Exposure is your friend use blepharostats + mosquito hemostats; pull the TEL towards you and to expose the surgery site as much as possible! Fluorescein stain before discharge! Neo/Poly/Dex ointment BID-TID (No corticosteroid if ulcer present & start topical antibiotic) Enucleation Modified Transconjunctival Approach Indications: Removal of blind, painful eyes Mayo scissors Curved Metzenbaum or enucleation scissors
Straight or slightly curved Metzenbaum (or Steven s tenotomy) scissors Soft tissue toothed forceps (Sauer forceps) 4-0 Vicryl 4-0 Prolene Procedure: Perform a lateral canthotomy The upper eyelid margin is excised 5 mm posterior to the mucocutaneous junction in a continuous fashion The lower eyelid margin is excised in a similar manner Grasp the TEL and excise it at the base Tip: get beneath the free edges of conjunctiva ventrally and medially to allow removal of as much ventral conjunctiva as possible Identify the dorsal free conjunctival edge, bluntly and sharply dissect down to sclera Incise the extraocular muscles then optic nerve Cut against sclera to avoid removing excessive tissue DO NOT apply any upward traction Pack the orbit with sterile gauze and wait until hemorrhage has resolved Apply manual compression if needed Irrigate the orbit using dilute lidocaine solution (5ml sterile water, 5ml 2% lidocaine) Excise any remaining conjunctival and medial caruncular tissue (often haired skin) Excise the openings of the dorsal and ventral nasolacrimal puncta Check - Did you remove all of the conjunctival tissue?! 4-0 absorbable suture layer (i.e. 4-0 Vicryl) in simple continuous pattern within periorbita (strong fibrous tissue layer, gently tug upwards to confirm) 4-0 absorbable suture layer (i.e. 4-0 Vicryl) in simple continuous pattern within subcutaneous layer 4-0 non-absorbable suture layer (i.e. 4-0 Prolene) in a simple interrupted or cruciate pattern to close the skin Consider submission for histopathology to determine primary vs. secondary glaucoma (risk to contralateral eye), potential causes for uveitis; if suspect intraocular neoplasm, etc. i.e. COPLOW University of Wisconsin x 1 week +/- Tramadol Oral Antibiotic x 1 week E-collar x 2 weeks