Initial examination / Indications

• Rule out existing uveitis – if active recommend controlling the inflammation prior to laser treatment
• Rule out other intraocular disease such as neoplasia (i.e., perform ultrasound)
• If significant corneal ulcers are present (i.e., larger than small bullae formation form edema), then treat with antibiotics, debridement, etc to attempt to heal prior to laser.
• Laser surgery most indicated if there is a consensual pupillary light response – i.e., chance for vision in glaucomatous eye.
• Blind, painful globes should be removed, have an intraocular silicone prosthesis, or a cosmetic prosthesis done. Laser can be done to help control IOP – but with poorer response than less chronic cases.
• Extensive client education - these eyes need treated indefinitely!

Preoperative treatment

Prior to considering laser – determine that there is no clinical response to antiglaucoma medications:

• Treatment with oral banamine for 7-10 days followed by oral Bute
• Treatment with topical timolol XE, Azopt or Cosopt bid to tid

Laser surgery indicated:

• 24 hours prior to laser surgery
  
  • Start 500 mg po bid of banamine (1000 lb horse)
  • Start topical antibiotics q6 hours
  • Continue Timolol XE
  • Continue these medications until surgery time

Surgical procedure

• Standing retrobulbar block with 10cc lidocaine
• Topical proparacaine given immediately prior to laser application
• Topical 2.5% phenylephrine given immediately prior to laser application
• Diode laser settings: 1000-1500 mW power; 5000 ms Duration; Repeat interval 0 (want to achieve about 25% pops)
• Aqueocentesis – either before or after laser applications – slowly remove 0.25-0.5 ml of aqueous humor through the limbus with a 25 to 27 gauge needle.
• Position of laser: 5-7 o’clock (ventrally) – 4 mm from the limbus; 10-1 o’clock OD and 11-2 o’clock OS: 4 –6 mm
• Number of spots – visual eye – 35 to 40 sites, spaced 1 mm apart. Blind eye – 40-60 sites

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Equine cataract surgery diagnostic protocol