Friday, October 30, 2015

Vision Surgery: The Facts

by Dr. Melanie Langford, O.D.

Historically,  the easiest/best way for patients to correct their vision was with either glasses or contact lenses. However, we now have multiple surgical options (i.e. LASIK, PRK) available that are used to treat common vision problems (e.g., nearsightedness, farsightedness, astigmatism).  All of these procedures aim to decrease or eliminate your dependence on glasses and/or contact lenses.

First and foremost, If you are interested in any surgical procedure, you need to make sure you discuss these options with your eye doctor. If you both decide you are a good candidate, then he or she will refer you to a surgeon  to confirm which procedure(s) is best suited for you.

At our office, we perform a preoperative examination which will include dilation of the eyes, corneal thickness measurements, and most components of a comprehensive exam. Following the surgery, depending on which refractive surgery you opt for, we will see you back for your post-op exams and follow your recovery/healing very closely.

Most types of vision correction surgery work by reshaping the cornea, or clear front part of the eye, so that light traveling through it is properly focused onto the retina located in the back of the eye. Other types involve replacing the eye’s natural lens. There are a number of different types of surgery to improve vision.

LASIK,  short for laser in-situ keratomileusis, is by far the most popular and well known refractive surgery. The majority of surgeons are now performing custom LASIK aka wavefront-guided LASIK. Wavefront guided LASIK uses a ray of light to determine where irregularities are in your cornea while the surgery is being done. The irregularities are displayed in a 3-Dimensional corneal map and will guide the surgeon during the procedure.  

Photorefractive Keratectomy (PRK) was the first refractive surgery approved in the US to remove tissue from the cornea to change the curvature. LASIK and PRK have similar outcomes. PRK is a surface procedure and does not require a flap like LASIK, so there is potential for less complications. PRK may also be safer for someone who has a cornea that is too thin for LASIK.

The main advantage of LASIK over PRK is that there is very little discomfort after LASIK and your vision clears within hours rather than days.

Implantable Contact Lenses (ICL)  are surgically implanted lenses that are inserted through a small incision at the edge of the cornea and attached to the iris inserted behind the pupil. This is considered when you have high amounts of nearsightedness that prevent you from having LASIK or PRK. The eye’s natural lens is left in place.

Refractive lens exchange (RLE)  is another non-laser surgery. It is very similar to cataract surgery. Instead of removing the eye’s natural lens that has formed a cataract, it involves removing a clear lens and replacing it with an artificial lens to reduce high amounts of nearsightedness and farsightedness. RLE has a higher risk of complications, so it is saved for severe correction needs.

Cataract surgery is now also considered a vision correction procedure. New lens implants can correct your  astigmatism, near vision and distance vision with multifocal IOLs.

 While the goal of LASIK surgery is to reduce dependency on glasses or contact lenses, having LASIK cannot guarantee 20/20 vision. Fortunately, most cases are successful in improving visual acuity (or sharpness). To be eligible for LASIK surgery, potential candidates must meet the following criteria:
1.       Your eyes must be healthy. Your optometrist will  assess and treat any  ocular health issues  before sending you for a consultation. A common disease is dry eye syndrome. If you have dry eyes, this may prevent your eyes from healing properly as well as lead to a worsening of symptoms following surgery.
2.       Your cornea must have the proper thickness and have no irregularities. Most refractive surgeries reshape the cornea, so in order to have a good outcome, you need to have a healthy cornea. If your cornea is too thin, then an implantable contact lens may be a good option.
3.       Your pupil size. If your pupil is too large, you will have increased risks of haloes and glare when driving at night.
4.       Your prescription. Results of LASIK with a very high prescription are less predictable and may require too much of your cornea to be removed. Implantable contact lenses or a refractive lens exchange may be your best option.
5.       Your age. Most procedures require you to be at least 18 years of age, but we prefer a minimum age of 25 because your prescription is more likely to remain stable. There is not an upper age limit. It is important for you to know that once you hit 40, you may require reading glasses. You may also consider monovision to correct one eye for distance and one for near. Also, older patients are at high risk for dry eye, so this must be treated first. If you have early signs of a cataract, a refractive lens exchange may be a better option than LASIK.
6.       Stable prescription. Your prescription must be stable for at least 12 months. It is common for children and teens to have changes in their prescriptions annually.  Prior to your LASIK surgery consultation and LASIK procedure, you must not wear contact lenses for a certain length of time. The precise length will be determined by your doctor on an individual basis. This ensures corneal stability and accurate assessment of your prescription prior to the LASIK surgery procedure.
7.       Your overall systemic health. Contraindications include systemic diseases that suppress your immune system such as HIV, Diabetes, and Sjogren’s. Also, certain medications can suppress your immune system. If your body has trouble healing, then you will have a high risk for a poor outcome. If you are pregnant, hormonal changes can alter your cornea. You should wait at least 12 months after you are pregnant or nursing to have LASIK.
Complications are becoming more rare thanks to advances in technology but they are still a possibility. You will likely experience temporary discomfort during the first few days after surgery and vision disturbances such as halos and glare especially at night, but these resolve within the first couple months.

Because LASIK involves creation of a flap on the front surface of the cornea, it could fail to adhere properly to the eye’s surface.   Wrinkles can develop and if not treated in time, may cause a decrease in best corrected visual acuity. Fortunately, a laser is now used to form the flap (as opposed to a blade) which make these complications extremely rare.

Significant undercorrection, overcorrection or regression is also a possibility. In some cases, you may still need glasses or contacts. It is possible for the laser to remove too much or not enough resulting in less than optimal vision. Your vision can also regress because you had the surgery before your prescription was stable. This can be treated successfully with additional PRK or LASIK in most cases.

Infection can also occur but because the cornea is replaced after the flap is made to act as a bandage, this is less common in LASIK than in surgeries like PRK. You will use antibiotics and anti-inflammatories before and after the surgery to prevent such complications from occurring.

In conclusion, it is important to have realistic expectations.  Make sure you are willing to educate yourself on the potential complications and risk factors of having refractive surgery. Do not look for shortcuts or bargain basement fees and you should not be casual about any refractive surgery. It can change your life in a very positive way but you need to be aware of all the potential risks.

source: www.allaboutvision.com

Dr. Langford
Dr. Melanie Langford practices full scope optometry at Family Vision Care and she enjoys working with patients of all ages. She is licensed in the treatment and management of ocular disease with therapeutic pharmaceutical agents, primary open angle glaucoma, and lacrimal irrigation and dilation. 

Family Vision Care
4310 Genesee Avenue,Suite 101
San Diego, CA 92117
Phone: 858-560-5181







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