Key questions to ask your surgeon prior to making the decision:
1. Do I have a visually significant cataract?
This depends on having vision usually worse than 20/40 on exam or glare test AND documented lens protein changes noted on a microscope. I take pictures to show my patients when a patient has any doubts to prove to the patient the presence of the cataract.
2. Do I have amblyopia?
(Amblyopia or “lazy eye” means one eye never developed the brain connection to see as well as the other eye or as good as 20/20 in childhood. This results in a chronic image blur from the “lazy eye” caused an inhibition of the visual signal to the bran. EyeMDs define amblyopia as a difference in vision of 2 or more lines between the eyes. For example, the good eye sees 20/20 and the “lazy eye” sees 20/30 or worse with the best glasses prescription before a cataract developed.
3. How much astigmatism do I have?
This determines what type of implant we should put in.
Astigmatism can come from the CORNEA (outer window of the eye) or LENS (inner usually clear structure behind the iris).
If the astigmatism comes from the cataract, we remove it with cataract surgery.
If the astigmatism comes from the cornea, we try to decrease as much of it as possible during the cataract surgery so as to minimize the need for glasses correction for this astigmatism. New innovative implants allow us to correct astigmatism better than in the past (for example, TORIC IOL, Trulign IOL, Restor Toric: FDA approved and almost on the market as of December 20, 2014).
3. Do I have dry eyes?
Tearing, foreign body sensation, discomfort, rosacea are all associated with dry eyes.
Since the tear film is “like a pair of glasses” in that it is crucial in giving one good QUALITY vision, is very important to maximize one’s tear film prior to cataract surgery in order to give one the best change for high quality vision. See Lid hygiene instructions on blog.
In general I discourage most patients with amblyopia (or only one good eye) from choosing a multifocal implant (MIOL) for several reasons.
1st: in the FDA trial for the ReSTOR lens:
94% could read without glasses if they were in both eyes, but only 64% could read without glasses when it was only implanted in one eye.
2nd: Patients with one good eye still should wear polycarbonate glasses for protection full time.
3rd: All eyeMDs try to avoid elective surgery in patients with only one good eye to avoid any undue risk. If a LASIK enhancement/adjustment is needed, or if you do not like multifocal vision, it could create a circumstance where additional surgery, such as an implant exchange, would be needed which again puts the eye at risk for complications, infections, loss of vision, loss of the eye, which though very rare are still present in most surgeries.
Have stated this, I have had many patients, though, who still wanted to have a multifocal implant or Crystalens implanted (many worked at the computer for many hours of the day and wanted to not have to have their glasses on at the computer) or did not have a severe amount of amblyopia and were will to take the risk of not having glasses on the whole time. All these patients did very well but were very aware of the risks prior to making an informed consent. I do not have long term data on these patients, so I cannot say with certainty that their choice not to wear glasses full time was an issue long term.
I did have 6 patients at Harvard who were told they had amblyopia their whole lives only to be very surprised to find their vision in their “lazy eye” was only 1 line different compared to their good eye after successful cataract surgery.
Some key points are as follows:
1. Do NOT get a multifocal implant if: (as the halos & glare might be an issue)
a. If you drive at night a great deal.
b. Are a type A personality & notice all irregularities in your vision/health.
c. Have terrible dry eye (can make halos/glare worse).
d. Had previous RK/LASIK in the past and are NOT willing to have a touch up or IOL exchange if the multifocal implant bothers you: if you are willing to take this risk, many patients are finding they are happy with a multifocal implant even after LASIK surgery.
e. Have significant macular pathology (hole, epiretinal membrane).
2. Do NOT get a Crystalens if:
a. You absolutely do not want to wear reading glasses.
b. You have previously had a vitrectomy.
3. Do NOT get a MONOFOCAL lens if:
a. You absolutely do not want to wear reading glasses: unless you have told your eye surgeon you want to be corrected so you can see for reading without glasses (but then you will need computer vision and distance vision glasses.
Articles showing some patients with Amblyopia & Multifocals implants do well:
1. The implant below is not available in US yet but general principle indicates that some patients with amblyopia do well with innovative-technology implants.
Refractive lens exchange for a multifocal intraocular lens with a surface-embedded near section in mild to moderate anisometropic amblyopic patients.
Implantation of the multifocal ReSTOR apodised diffractive intraocular lens in adult anisometropic patients with mild to moderate amblyopia.