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激光白内障手术

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The femtosecond laser technology that brought new levels of safety, accuracy and predictability toLASIKsurgery is also advancingcataract surgery. In our office, we call the procedure Refractive Laser-Assisted Cataract Surgery (ReLACS), but it also is known generally as laser cataract surgery.

In laser cataract surgery, an advancedfemtosecond laser代替或协助使用hand-held surgical tool for the following steps in cataract surgery:

  1. The corneal incision
  2. The anterior capsulotomy
  3. Lens and cataract fragmentation

Use of a laser can improve the precision, accuracy and reproducibility of each of these steps, potentially reducing risks and improving visual outcomes of cataract surgery.

The corneal incision

The first step in cataract surgery is making an incision in the cornea.



Optical coherence tomography is an imaging technology that helps your cataract surgeon to plan the location and depth of incisions made during a laser-assisted cataract surgery procedure. OCT scans offer high-resolution and even cross-sectional images, to make the cataract surgery as precise as possible. (Images: Vance Thompson, MD)

In traditional cataract surgery, the surgeon uses a hand-held instrument with a metal or diamond blade to create an incision in the area where the角膜meets thesclera. This incision allows the surgeon to gain access to the interior of theeyeto break up and remove thecataract, which is a clouding of the eye's natural lens that is located right behind thepupil.

Next, anintraocular lens (IOL)is inserted and implanted, to replace the cloudy natural lens.

The corneal incision is made in special way so it will self-seal when surgery is complete, without any need for stitches.

In laser cataract surgery, the surgeon creates a precise surgical plan for the corneal incision with a sophisticated 3-D image of the eye called an OCT (optical coherence tomography). The goal is to create an incision with a specific location, depth and length in all planes, and with the OCT image and a femtosecond laser, it can be performed exactly without the variable of surgeon experience.

This is important not only for accuracy but also for increasing the likelihood that the incision will be self-sealing at the end of the procedure, which reduces the risk of infection.

The capsulotomy

The eye's natural lens is surrounded by a very thin, clear capsule. In cataract surgery, the front portion of the capsule is removed in a step called an anteriorcapsulotomy, to gain access to the cataract.

It is very important that the remainder of the lens capsule that remains intact in the eye is not damaged during cataract surgery, because it must hold the artificial lens implant in place for the rest of the patient's life.

In traditional cataract surgery, the surgeon creates an opening in the capsule with a small needle and then uses that same needle or aforcepsto tear the capsule in a circular fashion.

In laser cataract surgery, the anterior capsulotomy is performed with a femtosecond laser. Studies have shown that capsulotomies performed with a laser have greater accuracy and reproducibility.

Studies also have shown that laser capsulotomies enable better centering of the intraocular lens, and IOL positioning is a significant factor in determining final visual outcomes.

Lens and cataract fragmentation

After the capsulotomy, the surgeon now has access to the cataract to remove it. In traditional cataract surgery, the ultrasonic device that breaks up the cataract is inserted into the incision. During thisphacoemulsificationprocedure, the ultrasound energy can lead to heat buildup in the incision, which sometimes can burn the incision and negatively affect the visual outcome by actually inducingastigmatism.

Best Candidates

blurred vision, clouded vision, light sensitivity, dim colors

An incision burn also has a higher chance of leaking and sometimes needs multiple sutures to close. The smaller the incision we use, the more this issue is important to consider.

The laser, on the other hand, softens the cataract as it breaks it up. By breaking up the cataract into smaller, softer pieces, less energy should be needed to remove the cataract, so there should be less chance of burning and distorting the incision.

Laser cataract surgery may also reduce the risk of capsule breakage. After the calculation of the proper implant power, there is no step more important for visual outcome than preservation of the capsule that the natural lens sat in. This capsule is as thin as cellophane wrap and it's important that the the portion that is left inside the eye after cataract surgery is undamaged, so it can hold the IOL in the proper position for clear, undistorted vision.

The reduced phacoemulsification energy required in laser cataract surgery may also make the procedure safer to the inner eye, which reduces the chance of certain complications, such as adetached retina.

Astigmatism correction at the time of cataract surgery

To reduce the need for prescriptioneyeglassesorreading glasses白内障手术后,转为叙述是很重要的e or no astigmatism is present after implantation of presbyopia-correctingmultifocal IOLsandaccommodating IOLs.

Astigmatism usually is caused by the cornea being more curved in one meridian than others (in other words, it's shaped somewhat like an American football). To reduce astigmatism, small incisions can be placed in the periphery of this more curved meridian; as the incisions heal, this meridian flattens slightly to give the cornea a rounder, more symmetrical shape (like a baseball).

This procedure is called limbal relaxing incisions (LRI) or astigmatic keratotomy (AK). Surgeons can perform LRI or AK manually with a diamond blade, and it is quite effective in reducing astigmatism.

During refractive laser-assisted cataract surgery, the OCT image can be used to plan laser LRI or AK incisions in a very precise location, length and depth. This increases the accuracy of the astigmatism-reducing procedure and increased the probability of good vision without glasses after cataract surgery.

Laser cataract surgery systems

A number of medical device companies offer laser systems for performing laser cataract surgery. Systems that have attainedFDAapproval and are currently available for laser-assisted cataract surgery performed in the United States include:

This LenSx femtosecond laser system has laser data entry at left, a joy stick control and an OCT screen at right, which offers the surgeon all-important guidance during laser-assisted cataract procedures. (Images: Alcon)

All FDA-approved laser systems for laser cataract surgery have shown excellent outcomes in clinical trials. The laser your surgeon has chosen for his or her practice is a matter of personal preference, based on specific features and other factors. Typically, the skill of your surgeon is more important than the brand of laser used for the laser-assisted steps of your cataract procedure.

Cost of laser cataract surgery

Refractive laser-assisted cataract surgery costs more than conventional options. The laser itself can cost the surgeon approximately $300,000 to $500,000, and additional costs are associated with using and maintaining the device.

Extracosts associated with laser cataract surgeryare unlikely to be covered by Medicare or private health insurance. Fees vary from one cataract surgeon to another, but it is likely you would pay a few hundred dollars extra per eye out-of-pocket for a laser-assisted procedure.

Cataract surgeons who use lasers say that their advantages are especially evident when it comes to high-tech, premium implants such as presbyopia-correcting multifocal IOLs and accommodating IOLs. The advantages can include better lens placement and therefore more accurate visual outcomes.

Conclusion

It is important to put this new technology into proper perspective. Traditional cataract surgery is very effective and successful. People who do not want to invest out-of-pocket money in laser cataract surgery can still feel confident about the traditional approach.

But if you want the best possible vision, laser cataract surgery is appealing. A more accurate incision, capsulotomy and astigmatic correction may help you achieve your goal of less dependence on glasses after cataract surgery.

To decide if laser cataract surgery is the best choice for you, ask yourcataract surgeonfor more information about this exciting technology during your preoperative exam and consultation.

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