Wednesday, May 18, 2016

Clear Lens Extraction


Clear Lens Extraction

Some patients may not be good candidates for Laser Vision Correction to reduce their need for glasses and contact lenses.  It could be that the cornea isn’t the correct shape or thickness or the attempted correction is too great to do with laser on the cornea.  Some people have early cataracts in the 50’s and 60’s and in that case, it makes more sense to go ahead and do the cataract removal with intraocular (IOL) lens implantation. 

The IOL outcomes of cataract surgery in recent years have become so accurate, that we can offer our patients who may not be candidates for LASIK a procedure whereby the “premature” cataract lens is removed and an IOL is implanted to improve vision and reduce the need for glasses and contact lenses.  
 


 "Outcomes of cataract surgery in recent years have become so accurate, that we can offer our patients who may not be candidates for LASIK a procedure whereby the “premature” cataract lens is removed and an lens is implanted to improve vision and reduce the need for glasses and contact lenses."
- R. Scott Hoffman, MD

We call this "Clear Lens Extraction".  It is a surgical procedure equivalent to cataract surgery in which the natural crystalline lens is removed and replaced with an intraocular (IOL) synthetic lens. When cataract surgery is performed the IOL usually corrects for distance vision, often requiring reading glasses to improve near vision for close work.

The difference is that Clear Lens Extraction, sometimes referred to as Refractive Lens Exchange (RLE) or Presbyopic Lens Exchange (PRELEX) , is done before cataracts (clouding of the natural lens) have developed. The goal is to reduce or eliminate the need for glasses and contacts for daily activities.  

Just as in cataract surgery, different types of IOL options are available to replace the natural lens, depending on the specific vision needs and the health of the patient's eyes. They are:

Monofocal IOL:  This type of lens has one focal point so the aim is usually to put the focus at distance, minimizing the need for distance glasses.  For normal print, though, one would need reading correction.  People often use reading glasses, like many experience in the 40’s and 50’s with natural loss of their near vision (presbyopia).

Mono-vision Correction:  This option uses a traditional monofocal lens in each eye. One eye is corrected for distance and the non dominant eye is corrected to be nearsighted to be able to read at near.  This makes the distance vision in that eye somewhat blurry, but many people tolerate this very well.  Patients who have mono vision correction in contact lenses and love it are particularly good candidates for this strategy.

Multi-Focal Lenses: These specialty intraocular lenses have two distinct focal points.  Multifocal implants create a focal point at distance and another at near.  This way, one can see at distance and for reading with a minimal or no need for glasses.  There can be some glare at distance, since part of the lens is out of focus in order to allow for reading.  



Toric (astigmatism correction) IOL:  Often there is significant astigmatism of the cornea, that is, the shape of the cornea is not spherical, as would be a perfect camera lens.  Astigmatic corneas are rather ellipse shaped, like the side of an egg.  The vision correction then must involve correcting the astigmatism.  This can be done with Toric IOL’s and corneal shape-changing incisions.   
After examining your eyes and reviewing measurements,  your eye surgeon will discuss your visual needs and expectations in order to recommend an IOL that is most suitable for your individual needs.

Pros:
·         The recovery is fast and there is excellent predictability of outcome.
·         This procedure is an alternative for patients who are not eligible for laser surgery.
·         Quality of vision is excellent.
·         This can correct high myopia (nearsightedness) and hyperopia  (farsightedness) that is out of the range of either laser surgery or phakic IOLs.
·         May be better than LASIK for some people over 40 years old.
·         Although this is an elective procedure, the patient will no longer develop a cataract later on because the lens has been removed and replaced by a clear implant.
·         There will be minimal postoperative discomfort.

Cons:
·         Patient might lose the ability to accommodate or may need glasses for near vision.
·         This procedure is more invasive than laser refractive surgery. It is done in the operating room with topical anesthesia and mild sedation
·         Each eye is done on different days, usually a week or two apart, to make sure that healing occurs as expected and there are no signs of serious rare complications.
·         As with all surgery there are some risks with these procedures.  Fortunately, serious sight-damaging risks such as infection, bleeding, retinal detachment, glaucoma and loss of vision are very rare.


- R. Scott Hoffman, MD

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