May 29, 2026

Femtosecond laser assisted cataract surgery, or FLACS, is a newer treatment option to correct cataracts and astigmatism. Cataract surgeon Mona Kaleem discusses FLACS and what sets it apart from traditional cataract surgery.

What is FLACS, and what makes it different from traditional cataract surgery?

Femtosecond laser assisted cataract surgery, or FLACS, is a noninvasive cataract surgery procedure used in the treatment of cataracts and astigmatism correction.

During the surgery, surgeons use a special medical laser to make very precise cuts in the eye. This laser is what makes FLACS different from traditional cataract surgery, which typically uses a blade to open the cornea. The laser causes a reaction called photodisruption: it fires super‑short pulses of energy that focus on a tiny spot and briefly turn that spot of tissue into plasma (a super‑energized gas). This breaks the tissue cleanly without burning nearby areas, so the cuts are smooth and accurate.

The laser can also be used to treat astigmatism, which happens when the cornea is shaped more like a football and causes blurry vision. By making precise cuts and helping position the lens correctly, the laser lowers the chance of astigmatism after surgery — a common reason for blurry or foggy vision afterward.

Who would benefit from FLACS?

FLACS may be appropriate for people with:

• Dense cataracts: FLACS is a great tool for people with dense cataracts. The laser makes precise corneal incisions, creates the opening in the lens capsule (capsulotomy), and softens the cataract, which reduces the ultrasound energy needed during surgery and may lessen corneal swelling and inflammation.
• Astigmatism: FLACS is also recommended for people who have astigmatism and are planning on getting an astigmatism correcting lens and for people who are interested in getting a multifocal lens. The laser improves the precision of the lens placement and the precision of the wounds that are made in the eye.

Who is not a candidate for FLACS?

People with the following conditions should not have FLACS:

• Individuals with severe dry eye who are at risk for corneal erosions or abrasions During the pre-operative visit, you should discuss this with your physician, who will review the overall health of your cornea. During the FLACS procedure, a contact lens is applied that creates suction on the eye. Therefore, those with risk factors for corneal abrasions or erosions, or with significant dry eye disease, are generally not considered appropriate candidates for this procedure.
• People with severe glaucoma are also advised not to undergo FLACS because of pressure fluctuations that can occur on the eye.

What happens during FLACS?

Like with other cataract surgeries, FLACS is performed while you are awake, with mild sedation and numbing eye drops given to ensure comfort throughout the procedure.

• The procedure beings with the patient positioned under the laser for treatment.
• During the procedure, the laser creates small openings, called a capsulotomy, which the surgeon uses to access and remove the clouded lens.
• The laser also creates guide marks inside the eye. These guides help the surgeon accurately place and center the new artificial lens. Once completed, the patient is moved under a large microscope, in the same room, for the remainder of the cataract procedure. The surgeon removes the cloudy lens and replaces it with a clear, artificial lens.

The procedure typically takes less than 30 minutes.

What happens after FLACS?

Recovery from FLACS is similar to recovery from other cataract surgeries.

• Patients often go home shortly after the procedure is finished and will have a patch or shield on the operated eye.
• They will be instructed on when to start recovery eye drops — usually that day — which help reduce inflammation. Most people return to light-duty work within two to three days after surgery.
• Full recovery typically takes one month, as the eye adjusts to the replacement lens and vision reaches its highest potential.

What are the risks of FLACS?

Your doctor will discuss possible risks before surgery, including residual astigmatism following the surgery, if the lens is not perfectly centered.

Medically reviewed by Mona Kaleem, M.D.