What is a Femtosecond Laser?
A femtosecond laser is an infrared laser that emits an array of laser energy at an extensively fast rate. This technology was primarily introduced for the utilization of laser-assisted in-situ keratomileusis (LASIK) eye surgery, which can correct significant vision problems in a short period of time. With a femtosecond laser, you can get precision and accuracy when performing delicate surgical procedures that would otherwise be difficult or impossible to achieve.
- A femtosecond laser emits optical pulses with a duration below one picosecond.
- In eye surgery, femtosecond laser is primarily used for laser-assisted in-situ keratomileusis (LASIK).
- A femtosecond laser-assisted cataract surgery allows for efficient cataract removal while being able to accurately correct astigmatism. It also offers decreased ultrasound energy used during cataract removal.
Understanding the Femtosecond Laser
Femtosecond laser is approved by the US Food and Drug Administration for cataract and refractive surgeries, such as laser-assisted in-situ keratomileusis (LASIK). A femtosecond laser is used during LASIK to create a corneal flap. The eye can be reshaped under the flap to get the intended visual outcome while protecting the eye during its healing process. Femtosecond laser may also be used during cataract surgery to aid with cataract extraction and with astigmatism correction.
Femtosecond laser technology has come a long way in the past few years. With models that emit less energy, procedures are now much more efficient and rapid. This means that less tissue is affected by the laser, which results in a higher chance of successful treatment.
Working mechanism of a Femtosecond Laser
- In laser-assisted surgery, tissue is segregated at the molecular levels.
- The femtosecond laser distorts stromal tissue via a process referred to as photodisruption.
- Targeted tissue undergoes vaporization.
- This creates a split where a cut is made.
Advantages of the Femtosecond Laser
The femtosecond laser has several benefits. It provides incisions with minimum damage to the surrounding tissue, and poses fewer complications, and the healing process is rapid post-surgery. Because of its precision, a femtosecond laser has extensive versatility and enhanced consistency. A femtosecond laser-assisted cataract surgery allows for efficient cataract removal while being able to accurately correct astigmatism. It also offers decreased ultrasound energy used during cataract removal.
Common Procedures Benefitting from a Femtosecond Laser
- LASIK – femtosecond laser is used to create the corneal flap during LASIK
- Cataract surgery – femtosecond laser can aid in cataract extraction and astigmatism correction
- Other corneal procedures such as lamellar keratoplasty and corneal transplants
Drawbacks and Complications from a Femtosecond Laser
While femtosecond lasers provide excellent outcomes, they do have certain rare complications:
- Opaque Bubble Layer (OBL)
Femtosecond laser treatment can cause gas bubbles to accumulate in the corneal flap interface. These bubbles can sometimes break down into the stromal bed, which could result in inaccurate registration and tracking by the excimer laser device. While this is generally harmless and usually doesn’t have any major consequences, if there is extensive central vertical gas breakthrough, it may trigger a flap buttonhole.
- Transient Light Sensitivity Syndrome (TLSS)
TLSS is also referred to as the good acuity plus photosensitivity (GAPP), and typically occurs weeks after a femtosecond laser. Patients may experience severe light sensitivity, but their exam is often normal. The usual treatment for TLSS is topical steroids for several weeks, which usually leads to resolution.
- Lamellar keratitis
This results from photodisruption-induced tissue injury and ocular surface inflammation, which leads to keratitis in the flap interface. It typically resolves without sequelae, but steroid drops may be needed along with careful follow-up.
- Rainbow Glare
Some patients may complain of “color bands” of light radiating from white light sources, referred to as rainbow glare. This occurs due to small irregularities on the flap interface, and usually improves over time.