Representative Cases : Topography-guided Photorefractive Keratectomy for Irregular Astigmatism following Penetrating Keratoplasty Purpose: Evaluation of efficacy and safety of topography-guided photorefractive keratectomy (TG PRK) for irregular astigmatism following penetrating keratoplasty (PK). Post-keratoplasty astigmatism often high and irregular. Previously variable results with PRK – haze, regression with poor quality of vision. Potential advantages with topography guided techniques to reduce irregular astigmatism and vision of quality. Methods: Retrospective case series. 87 cases with post keratoplasty astigmatism underwent TG PRK with Allegretto Wavelight (AW) laser Custom Topography Neutralization Technique (TNT) Trans-epithelial TG-PRK using TCAT. Application of mitomycin C 0.02% and standard post-PRK management. Data evaluated: 3, 6 and 12 months on: Uncorrected visual acuity (UCVA), Best spectacle corrected visual acuity (BSCVA), Manifest refraction (MR), Topography and Keratometry. Results: 87 eyes had treatment; 49 eyes had follow up of 12 months or more. UCVA: 35% (17) achieved UCVA ≥ 20/40, while none preoperatively BSCVA: 49% (24) had improved BCVA 35% (17) gained ≥ 2 lines 4% (2) lost ≥ 2 lines Refractive Cylinder: Pre-operative: 0.75D to 8.00D Post-operative: 0.00D to 6.00D Average improvement: 2.24D Topographic Cylinder: Pre-operative: 1.79D to 13.74D Average improvement: 2.92D Average Spherical Equivalent: improved by 1.70D, from -3.13D to -1.43D Retreatment rate: 15%. No cases of delayed epithelial healing. None with clinically significant haze (> +2) Conclusion: Early results of TG-PRK with TNT shows potential to improve both UCVA and BSCVA with good efficacy and safety. 35% UCVA improved to 20/40 or better, none preoperatively. High re-treatment rate: 15%. Almost half of the cases had improved BSCVA, more than one third gained ≥2 lines. References: 1. Ohno K., Customized photorefractive keratectomy for the correction of regular and irregular astigmatism after penetrating keratoplasty. Cornea Oct;30 Suppl 1:S41-4. doi: /ICO.0b013e b 2. Knorz MC, Jendritza B. Topographically-guided laser in situ keratomileusis to treat corneal irregularities. Ophthalmology Jun;107(6): Pedrotti E, Sbabo A, Marchini G. Customized transepithelial photorefractive keratectomy for iatrogenic ametropia after penetrating or deep lamellar keratoplasty. J Cataract Refract Surg Aug;32(8): Alessio G, Boscia F, La Tegola MG, Sborgia C. Corneal interactive programmed topographic ablation customized photorefractive keratectomy for correction of postkeratoplasty astigmatism. Ophthalmology Nov;108(11): Rajan MS, O'Brart DP, Patel P, Falcon MG, Marshall J. Topography-guided customized laser-assisted subepithelial keratectomy for the treatment of postkeratoplasty astigmatism. J Cataract Refract Surg Jun;32(6): Mularoni A, Laffi GL, Bassein L, Tassinari G. Two-step LASIK with topography-guided ablation to correct astigmatism after penetrating keratoplasty. J Refract Surg Jan- Feb;22(1): Pacific Laser Eye Centre tel: (604) CASE 1 – 39 y.o. male, PK x5yrs Preop: 22 months postop UCVA 20/400 UCVA :20/30 Rx: x048 20/25Rx : x030 20/20 -1 CT: 521µmCT: 447µm Pre-OpPos-OpPos - Pre Simon P. Holland MB, FRCSC, FRCS, MRCP; David T.C. Lin MD FRCSC; Umi K. Noh MB BCh BAO, Ms(Ophth) Pre-Op CASE 2 – TG PRK for post PK with retreatment PreopFinal Posop BSCVA: 20/60-1 UCVA: 20/40 MR: x122MR: x180 20/40 Topo Cyl: 9.40x113 Total Tx Cyl: 11.88D Pos - Pre Pre-Op of 1 o txPos-Op of 1 o txPos-Op of 2 o tx (Final) Final Pos-Op – Pre-Op