Options for Treating Z-syndrome

Recently, I had a patient that underwent cataract surgery with the use of an advanced technology intraocular lens implant who developed a relatively rare late complication known as z-syndrome.

The lens was a crystalens™ which is used to give a patient additional ability to accommodate their vision for near and reading, as well as for distance. The crystalens™ has two hinges symmetrically placed on either end which allows the central optical piece to flex and move as the eye attempts to focus.

This particular patient had outstanding postoperative results and was able to see well both at distance and near. This outcome remained stable for several months after the surgery, but at around three to four months he developed some mild inflammation in the eye.

He was treated routinely with topical steroid eye drops and the inflammation resolved. However, the result was the creation of some scar tissue which caused contraction forces around the lens implant compressing it. On examination, I noticed that one of the hinged portions of the implant was flexed forward while the other remained in the normal backward flexed position. I recognized it immediately as the much discussed, although rare, z-syndrome which is known to occur with these types of implants.

The result for this patient’s situation was that the affected eye was now moderately nearsighted with some astigmatism. So now he could still see quite well at near distances, but he had lost his distance vision correction. I could easily correct his vision by giving the patient a pair of eyeglasses, but one of the advantages of the crystalens™ is the reduced need for glasses under most conditions.

Because of the goal of minimizing the need for eyeglasses, I wanted to pursue all possibilities to correct the situation without an eyeglasses prescription. This situation was actually the first time that I had unquestionably recognized the z-syndrome in one of my crystalens™ patients.

I had previously seen other patients with earlier versions of the lens that were somewhat nearsighted immediately after implantation of the lens but the lens was in a perfect position. As this recent patient was clearly a case of z-syndrome, I made the decision to attempt a relatively simple laser treatment which has been described to have a very high rate of restoring these lenses to their normal functional position.

The procedure is called a YAG laser treatment and has actually been around for decades and used in a variety of situations even before the crystalens™ was developed. This laser can be used to precisely “cut” tissue surrounding a lens implant without cutting or damaging the lens itself.

In addition, it is a very non-invasive procedure, which requires no incisions or cutting of the eye. The laser and microscope remain completely external to the body while the laser energy can be aimed inside of the eye to cut the scar tissue around the implant. Unlike a more invasive incisional surgery, the patient doesn’t have to change to a hospital gown and doesn’t need an IV line. He simply places his head onto a standard eye exam (slit lamp) microscope similar to one found in every ophthalmologist’s office and the laser is connected to this microscope. Some anesthetic drops and a focusing lens may be placed onto the patient’s eye. Actually, in this particular case, the focusing lens was not even necessary.

For my patient, it was pretty visually obvious where the contraction bands of tissue were located. Therefore, I concentrated my laser treatment to the area that seemed to be the immediate source of tension which was compressing the lens hinges and creating the z-syndrome. As I applied the laser energy, I saw the contraction tissue being cut by the laser and immediately I saw the lens begin to shift position to the normal symmetrical backward flexed location. In a matter of minutes, the patient’s vision was restored to the perfect state that he had immediately after the initial cataract surgery.

There certainly were other options to correct this situation, but the simplicity and non-invasiveness of the YAG laser treatment makes it an ideal solution. A more invasive incisional surgery could be used to remove the crystalens™ implant and replace it with a standard lens. This solution has a couple of downsides.

First, it requires incisions and manipulation internally within the eye. Therefore, the risks of things like infection or injury to structures inside the eye is somewhat higher. Although those risks are low, it is still greater than with the non-invasive YAG laser option.

Second, changing the lens to a standard implant would eliminate the near accommodation advantage of the crystalens™ that gave my patient better reading vision after his surgery.

A third possible solution would be to perform refractive laser vision correction on the patient, e.g. Lasik surgery or PRK. Since my patient had very good vision even with the z-syndrome if he was properly fitted for eyeglasses, I could have simply treated him like one of my Lasik patients.

Lasik is a very effective, accurate, and relatively non-invasive way to treat the refractive problem in this situation with low risk. As long as the surgeon waits long enough after the initial cataract surgery to ensure that the eye is fully healed and stable, good results can be obtained with either Lasik or PRK. However, this option also has the downside that the near reading vision may not fully recover afterward since the z-configuration is not resolved.

For patients that are considering or have had the crystalens™ implant, you should be aware of the rare possibility of z-syndrome. If you experience a situation where your vision is initially very good after cataract surgery, but later your vision changes but remains correctable with an eyeglasses prescription, then you may be in this situation.

The take home message for you would be that simple solutions exist which can recover your vision to the state you had earlier with good distance and near vision.

Discuss these options carefully with your surgeon to determine the simplest and best solution for your case.

One Comment:

  1. i had a crystalens put in 5-ll-16 I saw well for a few months the complained of an eye ache. I called the Dr, he said I had 20/20 vision and I said I can not see well.
    I went to the University of Colorado in October. Both Dr. Davidson and Kahook
    confirmed my problem to be Z syndrome. The lens was taken out November–
    a fairly painful process. I paid alot of money to have the best lens $4400. Do
    I ask the doctor for a refund?. My eye isn’t right after all that.

Leave a Reply

Your email address will not be published. Required fields are marked *