Visual Rehabilitation With Customized Transepithelial Phototherapeutic Keratectomy After Penetrating Keratoplasty

To assess the visual rehabilitation parameters of adjunctive customized Transepithelial Phtotherapeutic Keratectomy after Penetrating Keratoplasty

Pallas Kliniken AG Department of Ophthalmology Zurich Bern Olten

Retrospective study of a case series of 4 eyes that underwent Customized Trans PTK with the Schwind Amaris 750 Excimer Laser after PKP. Customisation was performed based on OWF or CWF Data measured with a pyramidal sensor (Peramis) or Anterior OCT (MS39, CSO Schwind Eye-tech Solutions GmbH) according to the qualty of the data captured. Astigmatic correction was planned to the highest possible value and spherical adjustment was used for tissue saving purposes. OZ was limited within the interface of the corneal graft in order not to interfere with the stability of the wound. Parameters assessed included  BSCVA, K values, corneal pachymetry at the thinnset point, subjective refraction and SE, total RMS, HOAs, Coma and SA and lines gained

There was a marked gain of average 2 Lines on ETDRS chart (Range 0 to 4), 3.5D reduction of astimatism (Range 5.25 to 2.25) and significant reduction of total RMS at  5mm 5.21μm to 2.23 (Range 6.72 to 4.72 and 3.03 to 1.68) and a significant reduction of HOAs from 3.15μm to 1.2 ( Range 6.18 to 1.6 and 1.44 to 0.98). Coma was aslo reduced from 1.32μm to 0.65 (Range 2.11 to 0.93 and 0.85 to 0.38) and spherical aberration also from 1.07μm to 0.27 ( Range 1.88 to 0.34 and 0.44 to 0.05). Spherical equivalent sphere and Keratometry were reduced or increased according to the nature of the treatment (Hyperopic or myopic) and is not statistically relevant

Customised refractive transepithelial phototherapeutic keratectomy can reduce significantly the high order aberrations of the higly aberrated eyes that are induced after a penetrating keratoplasty and and reduce the irregularities and improvew best corrected visual acuity and the overall quality of the vision