Transcript Topography-Guided Photorefractive Keratectomy (TG-PRK)

Topography-Guided Photorefractive Keratectomy
(TG-PRK) for Keratoconus (KC) with
Simultaneous Collagen Cross-linking (CXL)
Using High-Resolution Excimer Laser
Simon Holland
David TC Lin
ASCRS, Chicago, Illinois 2012
*no financial interests*
Purpose
To evaluate efficacy and safety of simultaneous
TG-PRK with CXL using high-resolution
excimer laser, iVIS
Methods
 43 eyes keratoconus eyes underwent treatment with
high resolution excimer laser
 Trans-epithelial TG-PRK with iVIS using the
CIPTA program with simultaneous CXL (Dresden
protocol)
 Maximum refractive error corrected with minimal
residual stromal depth 300microns
 Data evaluated: pre-operative, 1, 2, 3 and 6 months:
- uncorrected visual acuity (UVA), best corrected
visual acuity (BCVA), topography, manifest
refraction (MR), symptom score, topography
and keratometry
iVIS TG-PRK with CXL for KC
Pre-op
UCVA:CF
MR: -4.50-1.00x080
Aim: –1.50
3 Months Post-op
UCVA: 20/80
MR: -1.50-1.50x150 20/30+
iVIS TG-PRK with CXL for KC
Pre-operative
4 months post-op
UCVA: CF
UCVA: 20/50MR: -6.50-4.75X110 20/60+ MR: -1.00-1.25x180 20/40-
Results
 43 eyes completed 6 months follow-up
 18 (42%) had ≥20/40 or better uncorrected visual acuity
(UVA)
 36 (84%) had ≥20/40 or better best corrected visual acuity
(BCVA)
 16 (37%) had BCVA improved, 4 (9%) improved BCVA 2
lines or more, 15 (35%) no change, 2 (5%) lost 2 lines or more
 Mean astigmatism decreased -2.67D pre-op to
-1.50D
 3 had delayed epithelial healing beyond 5 days with no
residual effects and no other complications
 Symptom scores at 3 months, n=20, improved in 11, no
change in 5 and worse in 4
Conclusions
 Early results of simultaneous TG-PRK with CXL with
the high-resolution excimer laser, iVIS, shows
potential to improve both UCVA and BSCVA in CL
intolerant KC patients with good efficacy and safety
 Advantages include central corneal regularization
possible with the iVIS CIPTA program but may be
offset by smaller treatment zones and less
reduction in symptoms