Introduction to Microkeratome

A epikeratome is a surgical device utilized in refractive surgery procedures to create a thin partial thickness flap in the cornea. This flap can then be lifted to access deeper corneal tissue for laser ablation. Also known as an automated lamellar keratome (ALK), a epikeratome uses a microtome head with a sharp blade to systematically cut a thin slice of corneal tissue.

How Does a Epikeratome Work?

A epikeratome works through precision blade movements to slice a uniform flap in the cornea. The device features a head with a sharp oscillating Microkeratom blade that makes multiple passes over the corneal surface. As the blade moves back and forth, it progressively shaves off thin corneal layers. This creates a hinged flap which can then be lifted to one side, similar to a cookie cutter.

The cutting head is attached to a suction ring that is placed on the eye to gently hold the globe in position. Suction flattens the corneal surface for an accurate cut. Epikeratomes allow surgeons to control variables like flap thickness, diameter and hinge position through settings on the device. Modern epikeratomes have built-in cameras and pachymeters for live intraoperative measurements as well.

Evolution of Epikeratome Technology

Initial epikeratomes primarily utilized oscillating metal blades to cut corneal flaps. However, newer laser-assisted and femtosecond laser-based technologies have now largely replaced mechanical keratomes.

Femtosecond lasers utilize ultrashort and extremely high-powered pulses of infrared light to cut corneal tissue with unprecedented precision. These lasers allow creation of thinner, more consistent flaps down to the micron level. They also reduce flap complications compared to mechanical epikeratomes.

Femtosecond laser-assisted cataract surgery is also revolutionizing refractive lens exchange and cataract procedures. The laser enables extremely accurate capsulotomies and lens fragmentation. This results in improved safety, predictability and outcomes for patients.

Modern epikeratomes still have roles in selected cases where femtosecond technology is unavailable or contraindicated. Oscillating metal keratomes continue to be important tools, though femtosecond lasers now drive the future of refractive surgery technology.

Applications of Epikeratomes

Some common applications of epikeratomes include:

- LASIK (Laser-Assisted In-Situ Keratomileusis): To create a partial thickness corneal flap for laser ablation under the flap to correct refractive errors like myopia, hyperopia and astigmatism.

- LASEK (Laser-Assisted Sub-Epithelial Keratectomy): Similar to LASIK but without lifting a flap. The epikeratome here is used to scrape off the corneal epithelium.

- PKP (Penetrating Keratoplasty): Can be utilized to help create donor buttons and host beds during corneal transplant surgery.

- DSEK/DSAEK (Descemet's Stripping Endothelial Keratoplasty): May assist in preparing donor tissue and host beds forpartial thickness grafts to treat corneal endothelial disorders.

- Refractive Lens Exchange: Allows creating a continuous circular capsulorhexis during cataract extraction and lens implantation for better refractive outcomes.

Conclusion

While femtosecond lasers now dominate refractive corneal surgery, microkeratome still hold relevance where other technologies are unavailable or inadequate. Refinements in epikeratome design have optimized flap creation outcomes. With ongoing innovations, they will likely continue enabling important corneal procedures around the world.