Posters

PTEK (phototherapeutic epithelial-guided keratectomy): a novel trans-epithelial OCT-guided PTK protocol combined with corneal collagen cross-linking for the reduction of irregular astigmatism in ectatic disorders - a case series

Poster Details

First Author: R. Cann UNITED KINGDOM

Co Author(s):    A. Davidson   E. Trocme   A. Barsam              

Abstract Details

Purpose:

Progressive corneal ectasia due to keratoconus or secondary to LASIK causes irregular astigmatism and a reduction in BCVA. Phototherapeutic keratectomy (PTK) combined with corneal collagen crosslinking (CXL) has been used to improve visual outcomes and halt or slow disease progression. We propose phototherapeutic epithelial-guided keratectomy (PTEK) as a novel PTK protocol that customises treatment to a patient’s individual epithelial thickness to safely optimise post-CXL refractive results. This prevents excessive stromal loss in patients where the apical epithelium is thin, whilst ensuring that the therapeutic benefit of apical smoothing is achieved in cases where the epithelium is thick.

Setting:

Ophthalmic private practice, London UK.

Methods:

Inclusion criteria: progressive ectasia due to keratoconus or post-LASIK ectasia, minimum corneal thickness of 400µm, no prior corneal surgery (other than LASIK). Epithelial thickness was measured by optical coherence tomography. To minimize stromal loss an intended ablation depth was set to 20+/-5µm beyond the thinnest epithelial location. Trans-epithelial PTK was then performed with simultaneous CXL by a single surgeon according to a modified Dresden protocol. Pre and post-operative follow-up (typically at 1 week, 6 weeks, 6 months, 12 months and 18 months) recorded BCVA, K Max, refraction and corneal astigmatism.

Results:

11 ectatic eyes of 9 patients were included (N=11). 8 eyes had keratoconus and 3 had post-LASIK ectasia. Mean length of post-operative follow-up was 8 months. There were no intra-operative complications. Post-operatively 1 eye developed sterile punctate epithelial erosions requiring increased antibiotics and 3 eyes had slight haze at last follow-up. At last follow-up mean improvement of BCVA was 1.2 lines (logMAR), mean reduction in K Max was 3.5 dioptres, mean improvement in cylindrical refraction was 2.25 dioptres, mean improvement in corneal astigmatism was 0.4 dioptres and spherical equivalent remained stable.

Conclusions:

PTEK is a new protocol for trans-epithelial PTK combined with CXL to treat progressive corneal ectasia that is customized to the patient’s individual epithelial thickness. This case series shows a mean improvement in BCVA, cylindrical refraction and corneal astigmatism, a mean reduction in K Max and spherical equivalent remained stable. Combined PTEK with CXL represents a safe therapeutic alternative for patients with progressive ectasia, which prevents or slows disease progression.

Financial Disclosure:

NONE