Corneal Surgeries(1).pdf

Corneal Surgeries Karen Gil MD, MHSN Corneal Wound Healing Phases regeneration of epithelium 1st Latent phase (first 6 h) Reduction of intracellular junctions hemidesmosomes disappear, removes damaged basal cells Infiltration of neutrophils...

Corneal Surgeries Karen Gil MD, MHSN Corneal Wound Healing Phases regeneration of epithelium 1st Latent phase (first 6 h) Reduction of intracellular junctions hemidesmosomes disappear, removes damaged basal cells Infiltration of neutrophils Apoptosis of keratinocytes 2nd Migration phase (6-36 h post-injury) Epithelial cells migrate to close the gap Start adherence to the BM Primary wave 18h and secondary wave 30h of neutrophils containing AMPs into the stroma antimicrobial proteins, protection Corneal Wound Healing Phases 3rd Proliferation phase (36 – 48 h) Basal cells from columnar layer proliferate to become wing and then superficial cells 4th Attachment phase (48h) Cells adhere firmly to the BM, intercellular junctions increase prevent separation, restore normal AMP in the tear film is present in all the process of would healing Antimicrobial peptide CAP37 protein https://doi.org/10.1089/wound.2016.0713 Corneal Scaring after Bowman’s, damage to stroma Severe chronic inflammation (Lymphocytes and neutrophils) leads to excess of fibroblast, collagen and fibrocytes disorganized Scaring Low VA growth factor Amniotic Membrane tx for corneal ulcers, pterygium, des epithelization Biological treatment (Bio-tissue) for regeneration of the cornea no neovascularization Decrease inflammation, scaring and angiogenesis Thick BM (inner layer of placenta) Contains collagen and proteins as: allows proliferation of collagen & keratinocytes (make collagen) fibronectin, laminins, proteoglycans and glycosaminoglycans Growth factors Promote epithelization Epidermal growth factor ECF, transforming growth factor Beta TGFβ, fibroblast growth factor FGF, platelet derived growth factor PDGF Amniotic Membrane It facilitates epithelium heals faster Epithelial cell migration Reinforces adhesion of Basal epithelial cells Promote epithelial differentiation Prevents epithelial apoptosis Minimize pain and neovascularization Is not consider a corneal transplant considered a patch PROKERA (FDA approved cryopreserved amniotic membrane) https://www.youtube.com/watch?v=tsjqI9lIolM https://www.youtube.com/watch?v=d5BA65PUU-Y Amniotic Membrane In conjunction with Exposure keratitis corneal transplants Neurotrophic corneal Limbal stem cell diseases deficiency Bullous Keratopathy Persistent corneal Ulceration (superficial or epithelial defect deep) RCE Post PRK haze SJS steven johnson Acute corneal burns DES dry eye Salzmann’s nodular Infectious keratitis degeneration Filamentary keratitis Fornix or socket reconstruction  Amniotic Membrane completely cover cornea, allow migration of cells from limbus deeper Amniotic Membrane Amniotic membrane used & to cover bare sclera after excision of primary pterygium. A-D: Serial photographs showing appearance of amniotic membrane graft. At end of 3 mo excellent integration and cosmetic appearance was achieved.Malhotra C, Jain AK. Human amniotic membrane transplantation: Different modalities of its use in ophthalmology. World J Transplant 2014; 4(2): 111-121 [PMID: 25032100 DOI: 10.5500/wjt.v4.i2.111] https://www.wjgnet.com/2220-3230/full/v4/i2/111.htmMalhotra C, Jain AK. Human amniotic membrane transplantation: Different modalities of its use in ophthalmology. World J Transplant 2014; 4(2): 111-121 [PMID: 25032100 DOI: 10.5500/wjt.v4.i2.111] Keratoplasties Kerato (cornea) + plasso (to form) Abnormal corneal tissue is replaced by a healthy donor cornea Partial – lamellar anterior or posterior Full thickness – penetrating keratoplasty Indications Optical – improve VA Tectonic – restore or preserve Therapeutic – remove tissue not responsive 80-90% Cosmetic - appearance  Keratoplasties full thickness descement is intact posterior Fuch’s Keratoplasties ~ 3,000 count in infants ~ 2,500 count in adults Donor Tissue must be healthy Eye banks Eye removed within 12-24 h of death Endothelial cell count - 2,000 - 2,200 cells/mm2 at least Infant corneas (