Technical differences between various excimer lasers

 

Most excimer lasers- Wavefront LASIK	Ex- 500 – Contoura™ LASIK with Occulyzer + Topolyser Vario (only at Shroff Eye, Mumbai)
1) Synchronized eye trackers @ 500 Hz = 6 millisecs response time	@1050 Hz Laser falls on programmed target	Therefore feedback time which is a response time of 2 millisecs
2)                        –	3  times sturdier laser lead	With Topolyzer Vario → Cyclotorsion for cylinder ≥  -1.5D
3) open to environment	Sealed optics stable energy	Auto neuro tracking and infrared camera in both topolyser and the laser. Also has a pupillometer for night vision issues. = Contura vision. Detects iris landmarks. Any from vertical to supine position means that eye rotates; therefore the compensation needs to be done. No human error as no punching of work. It is transferred software to software. The diagnostic and live image software overlaps to find differences and adjust those differences

 

 

Ex 500	Mel 90	Mel 80
1) 500 Hz	1) 250→500Hz	1) 250Hz
2) Wavefront optimized treatments. Does not induce higher order aberrations and maintains spherical profile	2) Becomes oblate and induces spherical aberrations	2) Becomes oblate and induces spherical aberrations
3) ASA + Corneal saving FDA approved -12.00D -14.00 D internal CE approval. Astigmatism ±5.00 D ±6.00 D internal   Optical zone 8.5 mm True optical zone 6.5mm	AAA algorithim claims to do ASA + corneal save ↓ Not FDA approved	ASA and tissue saving ↓ Maintain natural aspherically   more corneal aberrations   though issue saving option ↓ You will save tissue but not maintaining asphericity
6 D eye tracker 6 sigma multispectial eye tracker	3D tracker	3D tracker
With slit lamp Online Pachymetry	No integrated slit lamp No online Pachymetry	No integrated slit lamp No online Pachymetry

 

Topography linked treatments were used earlier on cases who had some laser treatment done on their cornea. Not used as Primary treatment.

But now with Contoura, it is the only FDA approved Topography treatment to be used as a primary LASIK treatment.

Topography LASIK address the corneal irregularities as most aberrations are from cornea.

 

 

With contura one can expect gain in line of acuity in 30% cases.

At Shroff Eye we have the diagnostics which no centre has ie. the Occulyzer plus the Topolyser Vario. This is important to detect early Keraconus.