Laser surgery uses focused beams of light to cut, reshape, or destroy tissue with a level of precision that traditional surgical tools can’t match. Rather than a scalpel, the surgeon directs a highly concentrated beam of a specific wavelength into the body, where it interacts with tissue in controlled ways. The result is often less bleeding, smaller incisions, and faster recovery compared to conventional surgery. Laser procedures are now used across dozens of medical specialties, from eye correction to brain tumor removal.
How Lasers Interact With Tissue
A surgical laser isn’t just a hot beam that burns through things. Depending on the wavelength, pulse duration, and power, it can interact with your body in several distinct ways. The most common is photothermal, where the laser heats tissue to seal blood vessels, shrink tumors, or make incisions with minimal bleeding. In photoablative procedures, the laser vaporizes thin layers of tissue with extreme precision, removing just microns at a time. This is the principle behind most laser eye surgeries.
There are also photochemical interactions, where laser light activates a drug that’s been absorbed by abnormal cells (a technique used in certain cancer treatments), and photoacoustic effects, where rapid pulses create shockwaves that break apart kidney stones or other hard deposits. The type of laser and the way it’s tuned determine which of these effects dominates, giving surgeons remarkably fine control over what happens at the tissue level.
Common Types of Surgical Lasers
Different procedures call for different laser wavelengths, and each type of laser has properties that make it suited to specific tasks.
- CO2 lasers produce a wavelength absorbed strongly by water in tissue, making them effective for vaporizing surface layers. They’re widely used in skin resurfacing and scar treatment because they trigger collagen remodeling in the underlying skin.
- Nd:YAG lasers penetrate deeper into tissue and are well suited for treating vascular lesions and stimulating collagen formation. Their 1064-nanometer wavelength also makes them useful in some internal procedures.
- Excimer lasers emit ultraviolet light that can reshape corneal tissue one microscopic layer at a time. They’re the workhorse of refractive eye surgery, used in LASIK, PRK, and similar procedures.
- Femtosecond lasers fire ultrashort pulses lasting just quadrillionths of a second. Their extreme precision allows surgeons to make cuts inside transparent tissue (like the cornea) without damaging surrounding structures, and they’re now being explored in combination with artificial intelligence for even greater accuracy.
Laser Eye Surgery
Refractive eye surgery is probably the most familiar application of medical lasers. Three main procedures dominate, and they differ in how the cornea is accessed and reshaped.
In LASIK, the surgeon creates a thin flap in the cornea, folds it back, and uses an excimer laser to reshape the underlying tissue before replacing the flap. Most patients return to work and driving the next day, with vision continuing to improve subtly over the following six months. LASIK corrects nearsightedness, farsightedness, and astigmatism.
PRK skips the flap entirely. Instead, the outer layer of the cornea is removed, and the excimer laser reshapes the exposed surface. Recovery takes longer: vision can stay blurry for up to three weeks, and a protective contact lens is worn for five to six days while the outer layer regenerates. PRK is often the better choice for people with thin corneas or those in contact sports where a flap could be dislodged by a blow to the face.
SMILE uses a femtosecond laser (not an excimer) to cut a small disc of tissue inside the cornea, which the surgeon then removes through a tiny incision. There’s no flap and no surface removal. Most patients see well within about a week. SMILE currently corrects nearsightedness and astigmatism, and it’s a good option for people who would benefit from PRK’s no-flap approach but want a faster recovery.
Preparing for Laser Eye Surgery
If you wear soft contact lenses, you’ll need to stop wearing them at least two weeks before your initial evaluation. Toric or rigid gas permeable lenses require three weeks off, and hard lenses need at least four weeks. This allows your cornea to return to its natural shape so measurements are accurate. The day before surgery, you should stop using creams, lotions, makeup, and perfumes, since residue near the eyes raises the risk of infection. You’ll also need someone to drive you home, because your vision will be blurry and you may receive medication to help you relax.
Skin Resurfacing and Cosmetic Uses
Laser skin treatments fall into two broad categories: ablative and non-ablative. Ablative lasers destroy the outermost layer of skin while heating the layer underneath, which stimulates new collagen production and improves skin firmness and texture. New skin covers the treated area in seven to ten days, but full recovery takes at least a month. You can expect swelling, itching, and temporary color changes during that period.
Non-ablative lasers leave the skin surface intact and work by heating deeper layers to stimulate collagen growth from within. Recovery is dramatically shorter. Your skin may be swollen or discolored for a few hours, and most people resume their normal routine the same day. The trade-off is that non-ablative treatments are less aggressive, so they typically require multiple sessions to achieve comparable results.
Both approaches are used to treat acne scars, surgical scars, stretch marks, wrinkles, and uneven pigmentation. CO2 lasers are the most common choice for ablative resurfacing, while Nd:YAG lasers are frequently used for vascular concerns and collagen stimulation.
Cancer and Tumor Treatment
Lasers have carved out a significant role in oncology, particularly for tumors that are difficult or dangerous to reach with traditional open surgery. One technique, laser interstitial thermal therapy (LITT), uses an MRI-guided laser fiber inserted through a small opening in the skull to heat and destroy brain tumors from the inside. It’s FDA-cleared and has become a valued option for patients with glioblastoma and other brain tumors where open surgery would carry too much risk, whether because of the tumor’s deep location or the patient’s overall health.
The advantages are meaningful: a short hospital stay, faster recovery, and less damage to surrounding healthy tissue compared to a full craniotomy. LITT is also used to treat epileptic tissue and radiation-damaged brain areas. Beyond the brain, lasers play roles in treating cancers of the cervix, skin, throat, and other sites where precision matters and preserving surrounding tissue improves outcomes.
Risks and Safety Measures
Like any surgery, laser procedures carry risks. The most common concerns include burns to surrounding tissue, scarring, skin color changes, and infection. Eye damage is a specific hazard for both patients and operating room staff, since some laser wavelengths can burn the cornea by vaporizing its water content. When lasers vaporize tissue, they also produce a plume of airborne particles containing carbon, bacteria, viral fragments, DNA, and over 41 toxic gases, requiring proper ventilation and filtration in the operating room.
Another less obvious risk involves surgical prep solutions. Skin-cleaning products containing iodine compounds must be completely dry before the laser is fired, because heat interacting with wet solution can cause chemical burns.
Safety standards for laser surgery are well established. In the United States, the Occupational Safety and Health Administration bases its requirements on American National Standards, and The Joint Commission uses the same benchmarks to evaluate laser safety practices. Internationally, the International Electrotechnical Commission sets global standards that cover everything from equipment design to administrative controls. In practice, this means laser-equipped operating rooms follow strict protocols: everyone wears wavelength-specific protective eyewear, windows are covered, flammable materials are kept away from the beam path, and a designated laser safety officer oversees compliance.
What Recovery Looks Like
Recovery varies enormously depending on the procedure. For minimally invasive laser treatments like LASIK or non-ablative skin procedures, you may be back to your routine within hours or a day. LASIK patients are generally advised to rest their eyes for two to four hours after getting home, avoid strenuous activity that day, and wear sunglasses outdoors and eye shields at night while sleeping. Most resume normal activities the next day, though the full healing process takes three to six months as vision stabilizes gradually.
For more intensive procedures like ablative skin resurfacing, expect a week or more of visible healing before new skin covers the treated area, followed by several weeks of sensitivity and color changes. Internal laser procedures like brain tumor ablation involve a short hospital stay, but recovery is still faster than the weeks of healing required after open surgery. In nearly every case, the recovery timeline for a laser procedure is compressed compared to the equivalent conventional surgery, which is one of the main reasons lasers have become so widely adopted across medicine.