The document discusses the advancements in corneal cross-linking techniques, highlighting standard and accelerated methods, with references to various studies and protocols. It mentions the beneficial effects on conditions such as keratoconus and post-LASIK ectasia, detailing the mechanisms and experimental results. Key comparisons between standard and accelerated cross-linking outcomes over one year are presented, noting differences in visual acuity gains and epithelial healing times.

1. Dr. Ragu Krishnan
Gomathi Eye and Cornea Centre
Mulund

2.  Acknowledgements:
-Wollensak et al-Effect of cross linking on
porcine cornea
-A J Kanellopoulos et al-Lasik Extra.
-Tobias Koller-UV-X-1000 and UV-X-2000.
-Luis F. Mejia.

3.  History:
Theo Seiler, Spoerl and Wollensak.
Since 1998.
 Mechanism:
Riboflavin:
Photosensitization.
Photo-protection.

4.  Beneficial effects:
Photo-oxidation and chemical bonding.
Collagen fibrils- size.
bonding.
resists digestion.
Increases resistance and induces
stabilization.

6. Indications:
Keratoconus.
Post-lasik/post RK ectasia.
Pellucid, Terrien’s.
Innovative:
Post PK.
Refractory microbial keratitis.
Temporary for PBK.

7.  Standard Cross-linking:
Dresden protocol, UV-A X1000.
 Uses the ‘top hat’ UV beam profile

9.  Accelerated Cross linking:
Reduces time and corneal dehydration.
Coupled with SimLC and Lasik extra.

10.  Accelerated Cross-Linking:
 A J Kanellopoulos- Athens, Greece-2005.
 Wellington Eye Clinic, New Zealand-2007.
 Paolo Vinciguerra, Italy-2007-2008.
 Switzerland and Bangalore, India.

11.  Accelerated Cross linking:
 Principle-Bunsen Roscoe law of reciprocity
 Experiments:
Wernli et al-40-45 mW/cm2
Hafezi et al-30 mW/cm2

12.  Accelerated Cross linking:
 IROC device- 9mW/cm2 for 10 mts.
 Avedro- various combinations
40mW/cm2 for 2 mts.
30mW/cm2 for 3 mts.
6mW/cm2 for 15 mts.
 Time and power vary, irradiation constant-
5.4J/cm2

13.  Accelerated Cross linking-Applications:
 SimLC- TPG PRK with Cross linking.
 The Athens protocol.
-Avedro used at 6mW/cm2 for 15 mts.
 Toponeutralization- TNT-NN group,
Bangalore -Avedro used
30mW/cm2 for 4 mts.

14.  Accelerated Cross linking:
Lasik extra-A J Kanellopoulos et al
Myopes, special indications.
All hyperopes.
 Avedro used 30mW/cm2 for 80 seconds.

18.  Other applications:
- AJ Kanellopoulos-Avedro-45mW/cm2 for 3
mts, after astigmatic keratotomy with
femtolaser.
-5-6 hours post Keraflex-Avedro-30mW/cm2
for 3 mts.
-Also being used after Conductive
Keratoplasty.

19.  Tobias Koller-8th International Crosslinking
meet-Geneva, Switzerland.
 Prospective comparision between:
-Standard and Accelerated Cross linking
-One year results

20. Standard Accelerated
 Technique Dresden protocol
 UV source UV-X-1000 UV-X-2000
 Beam profile Top hat Optimized
 Exposure 3mW/cm2 9mW/cm2
 Time 30 mts 10 mts
 Periphery same 12mW/cm2

23.  Results: At 1 year-
Standard Accelerated
Patients 156 45
Kmax change 0.8846D 2.631D
Flattening
Stable 59.1% 17.4%
1D 22% 17.5%
2D 16.1% 62.5%

24. Results: At 1 year-
Standard Accelerated
BCVA- Gain:
1 line 27.6% 19.9%
2 lines 24.3% 30%
Stable 30.9% 39.9%
BCVA-Loss-1 line: 17% 10.1%

25.  Results: At 1 year-
Standard Accelerated
 Epithelium 3 days 4.2 days
 Haze More

26.  Conclusions:
Time and benefits of combining procedures.
Improves work flow
 Spin offs:
Corneal endothelial damage.
Sustained effect of Cross linking.
Step in the right direction.