20 corneal surgery

20 corneal surgery

• 1.
  CORNEAL SURGERY 1. Penetratingkeratoplasty 2. Keratoprosthesis 3. Refractive surgery • Radial keratotomy • Photorefractive keratectomy (PRK) • Laser in-situ keratomileusis (LASIK) • Non-contact laser thermal keratoplasty
• 2.
  Penetrating Keratoplasty 1. Indications •Optical (e.g. bullous keratopathy, dystrophies) • Tectonic (e.g. severe stromal thinning, descemetocele) • Therapeutic (e.g. severe keratitis) • Cosmetic • Severe stromal vascularization • Absence of corneal sensation • Progressive conjunctival inflammation (e.g. pemphigoid) • Tear film dysfunction • Glaucoma 2. Adverse prognostic factors
• 3.
  Technique of penetratingkeratoplasty Excision of donor tissue a, b - Excision of host tissue c - Fixation of donor tissue
• 4.
  Signs of lategraft rejection Epithelial • Intensive topical and periocular steroids • Occasionally systemic steroids Endothelial Treatment Iritis and inflammation at graft-host junction Endothelial precipitates (Khodadoust line) Linear epithelial opacity Subepithelial opacities
• 5.
  Keratoprosthesis Indications Bilateral blindness fromocular pemphigoid, chemical burns or repeated graft failure Insertion of artificial lenticule into corneal stroma • Glaucoma Main complications • Retrolenticular membrane formation Technique
• 6.
  Radial keratotomy Main indications •Stable myopia of up to 8D • Otherwise normal cornea • Accidental perforation • Intrastromal epithelial cysts Main complications • Decreases myopia by flattening cornea • Deep incisions from edge of optical zone to limbus
• 7.
  Photorefractive keratectomy (PRK ) Indications • Stable myopia up to 6D with astigmatism no more than 3D • Hypermetropia up to 2.5D Main complication Subepithelial haze which usually resolves after 1-6 months Reshaping of cornea by excimer laser ablation of Bowman layer and anterior stroma Technique
• 8.
  Laser in-situ keratomileusis(LASIK) Indications - similar to PRK but corrects higher degrees of myopia • Thin flap of cornea fashioned • Bed treated with excimer laser • Flap repositioned Complications • Wrinkles in flap • Cellular interface proliferation Technique
• 9.
  Non-contact laser thermalkeratoplasty Indications • Patients over 40 years with hypermetropia up to 2D • Following overcorrection of myopia • Corneal curvature is steepened by application of laser heat to stroma • Holmium laser spots applied to mid-cornea
• 10.
  Non-contact laser thermalkeratoplasty Indications • Patients over 40 years with hypermetropia up to 2D • Following overcorrection of myopia • Corneal curvature is steepened by application of laser heat to stroma • Holmium laser spots applied to mid-cornea