Management of Epithelial Ingrowth after LASIK. Helen K. Wu, MD New England Eye Center Tufts University School of Medicine Boston, MA

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1 Management of Epithelial Ingrowth after LASIK Helen K. Wu, MD New England Eye Center Tufts University School of Medicine Boston, MA

2 Acknowledgements IOP Ophthalmics Staar Surgical

3 Case Presentation 46 year old man who underwent LASIK in Texas 15 years prior He recalled that his eyes were quite uncomfortable after the initial procedure Recently returned for enhancement with LASIK flap lift OD and was again uncomfortable postoperatively Returned to Boston for follow up care 3 weeks later (1/12) Found to have epithelial ingrowth at temporal edge of flap and old nasal peripheral flap melt OD; OS with temporal haze under flap

4 Epithelial Ingrowth

5 Case Presentation Flap was lifted and epithelium was scraped after progression was noted (2.5 months postop; 2/12) The patient was found to have loose epithelium (occult ABMD) during procedure Fibrin glue was placed at edge of flap with bandage contact lens The patient did well until small tongue of epithelium reappeared at edge of flap five months later (July 2012)

6 Case Presentation Due to small size and peripheral location of epithelial ingrowth, plus severe loose epithelium at time of previous procedure, YAG laser treatment to flap interface was performed (9/7 and 10/25/12) After two treatments, the island of epithelium appeared to regress and stabilize

7 Epithelial Ingrowth Incidence is low after primary LASIK (1-5%) Incidence is markedly increased with LASIK retreatments with flap lifts years later (31% at one year with 10% melting in one study-perez- Satonja JJ et al, Ophthalmology 1999 ) Potential danger is melting of the overlying flap, irregular astigmatism, photophobia, ciliary injection and loss of vision

8 Risk Factors Loose epithelium/ anterior basement membrane dystrophy Corneal abrasion Thin or buttonhole flap Poor flap adherence Trauma- blunt or penetrating Lifting of flap years after LASIK Poor lid closure Viral conjunctivitis

9 Risk Factors Incidence with microkeratome appears to be higher than with femtosecond flaps Tear in flap Previous radial keratotomy Hyperopes more likely than myopes to have epithelial ingrowth (Packer) Interface keratitis Suture tract from phacoemulsification or other surgical procedure Diabetes Older age Presence of epithelial ingrowth in other eye

10 Diagnosis of Epithelial Ingrowth Clinical appearance May masquerade as epithelial defect on flap (Azar DT, et al, JCRS 1999) Fluorescein may stain the fistula or pool next to retracted flap edge Corneal topographyirregular astigmatism Differential diagnosis- infectious keratitis or DLK Azar DT et al, JCRS 2003

11 Classification (Machat) Grade 1- thin layer of cells advancing no more than 2 mm into flap edge, well-demarcated white line that may be difficult to detect, no flap changes, nonprogressive Grade 2-thicker, discrete cells within nests, easily visible, no demarcation line, at least 2 mm from edge, edge is rolled or grey but no melting, progressive Grade 3-thick, geographic areas of white necrotic epithelial cells without demarcation line, flap edge rolled and thick, progressive melting and haze developing peripheral to melted flap Machat JJ, Slate S, Probst SE. The Art of LASIK, 2nd ed. Thorofare, NJ SLACK;

12 Treatment Algorithm Grade 1 (mild and non-progressive)- Observe Grade 2- may need lift flap and scrape, secure flap, if progressive (may not be progressive but treat if causing topographic irregularity) Grade 3-urgent treatment necessary to remove epithelium from interface

13 Management Scraping of both surfaces Alcohol, proparacaine, or MMC PTK Suturing Tissue adhesive YAG laser Amniotic membrane grafting Full cornea patch Annular patch

14 Epithelial Scraping The flap is reflected and the surfaces of both the stromal bed and the underside of the flap, as well as the flap edge, are scraped with a spatula or blade The interface is rinsed with sufficient amounts of saline and repositioned, being careful not to re-implant epithelial cells under the edge of the flap A bandage lens is typically placed (one study shows increased risk with BCL) Recurrence rate as high as 44%

15 Adjunctive Agents To Kill Residual Epithelial Cells Proparacaine 0.5% drops applied to stromal bed and underside of flap Alcohol- 50% solution; apply with sponge and rinse MMC PTK- 10 microns on stromal bed and underside of flap May have toxic effects to underlying stroma (MMC or alcohol) or induce refractive changes (PTK)

16 Suturing the Flap Several (5-7) interrupted sutures are placed radially with knots buried on the peripheral cornea Suture tension is important as it may induce astigmatism or cause the flap to have additional folds The sutures can be left in place for one to several weeks From Devgan U, OSN 2009

17 Tissue Adhesive The fibrin glue can be used to seal the edges of the flap Painting on each component one at a time results in a more controlled procedure than blending the two Glue should not be excessive or it will be knocked off with lid motion

18 Transepithelial PRK If epithelial ingrowth occurs through a buttonhole in a thin graft, transepithelial PRK/PTK may be sufficient to ablate through flap entirely (Kapadia MS and Wilson SE, AJO 1998), obviating the need for flap lift MMC is typically used intraoperatively as an adjunct to prevent severe haze reaction postoperatively

19 YAG Laser Can be very helpful if cells are near center of flap YAG energy should be delivered to the corneal flap interface beginning in the center of the opacity Use the least amount of energy required to create a cavitation bubble (average 0.6 mj) Small cavitation bubbles will obscure a view of the epithelial cells Multiple treatments may be required From Ayala MJ et al, AJO 2008

20 Amniotic Membrane Grafts Amniotic overlay- Lee ES, et al JCRS 2006 Utilizes amniotic membrane over entire cornea (secured by 8-0 nylon in episclera) as pressure patch to secure flap when a central flap defect precludes suturing the cornea Annular amniotic membrane patch-azar G et al, JCRS 2010 Peripheral donut shaped patch graft in patient with flap melt to cover flap gutter and mechanically prevent epithelial ingrowth

21 Annular Amniotic Membrane Graft Image from Azar G, et al. JCRS 2010

22 Annular Amniotic Membrane Graft Fibrin glue is placed under amniotic membrane and sutures are placed peripheral to flap edge Image from Azar G, et al. JCRS 2010

23 Severe Cases With Flap Melting May need to truncate flap and do lamellar keratoplasty or PTK Epithelial ingrowth involving visual axis Haze in cornea after flap removal From Lam DSC et al. JCRS 1999

24 Prevention Consider surface ablation instead of LASIK for cases with ABMD Consider surface ablation with MMC for enhancement procedure as alternative to lifting flaps several years after LASIK Try using femtosecond laser to create a new side cut at the edge of an old LASIK flap if flap lifting is desired (Coskunseven E et al, JRS 2012) From Coskunseven E, et al. JRS 2012

25 Summary Epithelial ingrowth may be managed successfully if handled promptly Scraping and replacement of flap alone may be inadequate Other methods, such as suturing of flap, tissue adhesive, or amniotic membrane patching, can facilitate flap adhesion YAG treatment of areas of epithelial ingrowth can be very helpful in recalcitrant cases Prevention may be the best cure