ABSTRACT NUMBER - 3206

TOPOGRAPHY GUIDED PHOTO REFRACTIVE KERATECTOMY FOR THE IRREGULAR CORNEA WITH THE VANCOUVER CUSTOM TOPOGRAPHY NEUTRALIZATION TECHNIQUE (TNT)


Greg T Moloney, David TC Lin,Simon P Holland

Meeting:  2013 RANZCO


SESSION INFORMATION

Date: 03 Nov 2013

Session Title: RAPID FIRE PAPER SESSION

Session Time: 4:00 pm - 5:30 pm

Purpose:
To evaluate the efficacy and safety of theVancouver Custom Topographic Neutralization Tech-nique (TNT) in topography-guided photorefractivekeratectomy (TG PRK) for irregular astigmatism inectasia, keratoconus and following penetrating kerato-plasty (PK).

Methods:
Retrospective chart review of patientsundergoing TG PRK with Allegretto Wavelight (AW)laser using the Vancouver Custom Topography Neu-tralization Technique (TNT) to modify the manifestrefraction based on the refractive changes predictedfrom the plano TG treatment. After treatment, mito-mycin C 0.02% was applied in all cases followed bystandard post-PRK management. Uncorrected visualacuity (UCVA), best spectacle corrected visual acuity(BSCVA), refraction, keratometry (K), topography andhaze on a 1–4 scale are evaluated at 1, 3, 6, 12 and 24months post treatment.

Results:
47 post PK, 18 ectasia and 135 keratoconuspatients completed 12 months follow up. In the postPK group, 10 eyes (36%) had UCVA of 20/40 or betterwhile the best UCVA prior to treatment was 20/50. 12(43%) had BSCVA improved, 7 (25%) gained 2 linesor more, while 3 (11%) lost 2 lines or more. In theectasia group, 10/18 (56%) had UCVA of ?20/40. 13(72%) had improved BCVA while 10 (56%) gained 2lines or more. In the keratoconus group 72 (53%) had?20/40 or better uncorrected visual acuity (UCVA), 76(56%) had BCVA improved, 38 (28%) improved BCVA2 lines or more, 5 (4%) lost 2 lines or more. Meanreduction of astigmatism was 1.47 diopters (D). Com-plications included delay in epithelial healing, withsubsequent haze, 2 sufficient to reduce BCVA morethan 2 lines, 1 undergoing PK, HSV keratitis, 1 recov-ering pre-operative BCVA after PTK.

Conclusion:
Topography-guided PRK is effective forimproving irregular corneal shape, but is prone toinducing refractive change in the process. TheVancouver custom TNT offers a compensatory ablationprofile for this change, with promising early efficacyand safety in a variety of clinical settings.

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