Collagen cross-linking (CXL) for keratoconus (KC) with simultaneous topographical-guided photorefractive

keratectomy (TG-PRK)Simon Holland, MD, FRCSC, FRCS(Eng),

MRCP, FRC OphDavid TC Lin, MD, FRCSC

Pacific Laser Eye CentreUBC Dept of Ophthalmology

ASCRS, San Diego 2011

*No financial interests

Purpose and Methods To evaluate early results of efficacy and safety of

simultaneous TG-PRK (Custom TNT) with CXL in contact lens intolerant KC using the Wavelight Allegretto laser

105 eyes of 72 patients Target: -1.25 or maximum correction of

astigmatism if insufficient thickness Minimal predicted residual stromal depth

320microns

Methods Epithelial removal by trans-epithelial laser Topography-guided PRK with TCAT software (Custom

TNT), modified by refraction and proprietary protocol Riboflavin 0.1% in dextran, repeated drops until presence of

aqueous staining Hypotonic dextran if <400 um UV irradiation with additional drops of riboflavin (up to 20

minutes) UV 370 um, 3mW/cm2 - 5.4 J/m2 Bandage contact lens, standard post PRK

management

TG PRK X-Linking for Keratoconus20 year-old male 11 months post-opUCVA: 20/200 UCVA: 20/50Pre-op: +4.00-4.00x075 Rx: -0.25-1.25x080 BCVA: 20/30 BCVA: 20/30 CT: 486 CT: 412

TG PRK X-Linking for Keratoconus19 year-old male 9 months post-opPre-op: -1.75-0.75x075 UCVA: 20/25BSCVA: 20/30 Rx: -0.50-0.25x120 20/20 CT: 493 CT: 447

TG CXL PRK for KERATOCONUS

Pre-op: +1.75-4.00x060 6 months post-opBSCVA: 20/30- UCVA: 20/30 RX: +0.25-0.75x170 20/25

TG CXL PRK for KERATOCONUS Pre-op: -2.75-2.25x010 12 months post-opBSCVA: 20/20- UCVA: 20/30-

RX: +0.50-0.50x020 20/30-

Results 32 eyes completed 1yr follow up 22 (70%) had ≥20/40 or better uncorrected vision (UCVA) at six

months; all had BSCVA of 20/40 better 4 eyes lost two lines, six gained ≥2 lines Mean astigmatism ↓ from -2.60D pre-op to -1.05D at 1 year 5/22 using refractive correction at 1 year with symptom improvement

in 19/22 Complications: 3 delayed epithelial healing beyond one week, 1

herpetic keratitis = all 4 recovered pre-op BSCVA

Complications: HSV keratitis

20yr old male RGP intolerant, KC OS>>OD Pre-op, OS: +4.00-4.00x075 20/30 10 day post-op: remove BCL, photophobia,

dendrite – Valvocyclovir, Trifluridine 18mth post-op: UVA 20/30

OS: -0.25/-1.25x115 20/25-

Conclusions: Simultaneous Topography-guided PRK with CXL

Satisfactory early results were achieved with simultaneous TG-PRK (Custom TNT) with CXL

Degree of refractive correction limited by corneal thickness although 70% were able to gain 20/40 or better UCVA at 12 months

Simultaneous TG-PRK (Custom TNT) with CXL is a novel technique with the ability to improve both UCVA and BCVA in keratoconus

Thank-you