Category Archives: VISX

LASIK (flap) versus Surface PRK (no flap)

By | Calgary, Dry eye, Epi-lasik, Epilasik, Intra-LASIK, Laser Eye Surgery, Laser vision correction, LASIK, Ophthalmologist, Ophthalmology, Opthamologist, Photorefractive, PRK, Refractive Surgery, Surgeon, VISX | No Comments

STAR S4According to some reports over 28 million laser vision correction surgeries have been performed worldwide since the excimer laser was developed in the 1980s.  Both PRK surface laser and LASIK surgeries use the excimer laser to reshape the corneal surface.  The main difference between the two types of laser vision correction methods is the creation of a corneal flap with LASIK and treatment on the surface of the cornea after removing the thin layer of epithelial cells with PRK.  eyelabeled

 

Advances in both the excimer laser and in flap creation technology have resulted in a variety of names for laser vision correction surgeries.  Flap surgeries include LASIK and IntraLase and no flap treatments include PRK, LASEK, and Epi-LASIK.  With LASIK a small oscillating blade in a device called a microkeratome is used to cut the LASIK flap.  With IntraLase the femtosecond laser is used to create a corneal flap.  Originally called “flap and zap”, with LASIK and Intralase the flap is lifted and the excimer laser reshaping is done on the underlying corneal tissue.  With no flap treatments the excimer laser energy is applied directly to the surface of the cornea.

PRK surface laser vision correction gained in popularity from it’s introduction in the 1980s over the next decade.  LASIK was introduced in the 1990’s  and became the most popular laser vision correction by the early 2000’s due to faster recovery.  Within the past several years there has been a shift back towards surface treatments due to the improvements in post operative management and in excimer laser technology.  It has also been determined that for some people PRK surface treatments may be a better choice.  The reasons that PRK may be recommended include:

1. Risk of flap shift or trauma with job or sports activities.

2. Thin corneas that may be a risk for ectasia (unstable cornea with progressive thinning) with LASIK flap.

3. Very steep or very flat corneal curvatures that may increase LASIK flap complication risk.

4. Previous injury or eye or eyelid surgeries that may raise the risk of LASIK flap complications.

5. Moderate dry eye might be worsened by the deeper disruption of corneal nerves with LASIK flaps.

Both LASIK and PRK have be demonstrated to produce equally good results over 6 months or more.  In the short term of days to weeks LASIK patients will recover vision more quickly.  So taking a short term perspective it makes sense that people may choose a LASIK flap laser vision correction method.

Taking a long term approach there are advantages to forgeting the LASIK flap and choosing a no flap PRK surface treatment.  Advantages of a no flap PRK approach include:

1. no LASIK flap = no flap complictions such as incomplete flaps, buttonholed flaps, partial flaps

2. no LASIK flap eliminates the risk for flap dislocation in the future

3. no LASIK flap means there can not be complications like epithelial ingrowth, diffuse lamellar keratitis, interface debris, flap wrinkles,  or other LASIK flap related complications.

4. Less risk of a weak and unstable cornea called corneal ectasia due to the LASIK flap disrupting the cornea more deeply than surface PRK.

5. Possibly less risk of severe dry eye with surface PRK.

To make the choice that is right for you, first find out if you qualify for laser vision correction and then learn the pros and cons of the treatments available to you.  If you have questions about laser vision correction or wish to book a complimentary evaluation with Dr. Anderson Penno, contact Western Laser Eye Associates.

 

Western Laser Eye Associates Welcomes Dr. Deepak Khosla, Ophthalmology Associate

By | Blepharitis, Calgary, Cataracts, Dr. Khosla, Dry eye, Eye health, glaucoma, Laser Eye Surgery, Laser vision correction, macular degeneration, Ophthalmologist, Ophthalmology, Opthamologist, Optometry, Photorefractive, PRK, Refractive Surgery, Uncategorized, VISX | One Comment

Western Laser Eye Associates is excited to welcome Dr. Deepak Khosla as the newest member of our eye care team.  Dr. Khosla has a special interest in medical retina and general ophthalmology.  He speaks a number of languages including Hindi, Punjabi, Urdu, and Tamil and has a number of years of experience in ophthalmology.  Urgent eye care problems and new patients are welcome.

Dr. Khosla is a general ophthalmologist which differs from an optometrist in the training and scope of practice.  Ophthalmologists are “Eye MD”s with a medical degree and training in all systems in the human body.  An optometrist has specialized training in eye health and also may have more experience and training in the optics of prescribing glasses and contact lenses.  Western Laser Eye associates has a diverse team including 2 optometrists who specialize in eye health including dry eye, glasses and contact lens prescriptions, and eye muscle testing.  Dr. Khosla joins Dr. Anderson Penno as a second ophthalmologist and together they cover a wide array of eye health problems including screening for diabetic patients and treatment of many common eye diseases such as glaucoma and macular degeneration.  Dr. Khosla and Dr. Anderson Penno also care for urgent conditions including foreign body, eye infections, styes, and retinal tears.

Dr. Khosla offers Saturday appointments for select appointments.  To inquire about an eye health exam call 403.247.1477 or ask your medical doctor to fax a referral to 403.247.9774.

If you have questions about laser vision correction or wish to book a complimentary evaluation with Dr. Anderson Penno, contact Western Laser Eye Associates.

Is PRK / Advanced Surface Ablation better than LASIK?

By | Customvue, Laser vision correction, LASIK, PRK, Refractive Surgery, Surgeon, VISX | No Comments

PRK (photorefractive keratectomy) was the first laser vision correction used to eliminate glasses and contact lenses. The first PRK was done in North America in the 1980’s and PRK has remained an excellent way to eliminate nearsightedness, farsightedness, and astigmatism.

PRK involves removing just the surface layer of cells on the surface of the cornea (the clear winshield-like structure on the front of the eye) and then reshaping the surface using the excimer laser.  A contact lens is placed on the surface for three to five days as the surface cells grow back to cover the cornea.  Most people are back to usual activities in 7 to 10 days.

LASIK (laser in situ keratomileusis) was developed in the 1990’s as a way to speed up the recovery from laser vision correction.  Also called “Flap &  Zap”, LASIK involves cutting a flap from the cornea, folding it back out of the way to reshape the surface underneath with the excimer laser, and then replacing the flap to it’s original position.  This allows people to be back to usual activities within a day or two but does carry higher risks;  the LASIK flap is more complicated to create, the flap can be shifted even months or weeks later, and the cornea is weakened more from the LASIK flap.

For over twenty-five years surgeons have preferred to use PRK for people with thin corneas or other factors that may make LASIK too risky.  With the newer excimer lasers a customized wavefront laser pattern can be used.  This custom wavefront treatment uses a map of the patients vision system to create an individualized laser treatment pattern – much like a fingerprint that is customized to each individual eye.  Some surgeons believe that a customized treatment is more effective with PRK because the LASIK flap will cover up the finely customized wavefront treatment.

Many surgeons around the world are choosing PRK as their preferred way to do laser vision correction due to the excellent results and safety.  Although the risks are low with LASIK, they are lower with PRK and most complications of PRK are easier to treat than a complicated LASIK flap.

For people who are looking for safe and effective laser vision correction the combination of PRK/Advanced Surface Ablation with customized wavefront laser treatment is an excellent choice.

If you have questions about laser vision correction or wish to book a complimentary evaluation with Dr. Anderson Penno, contact Western Laser Eye Associates.

Why choose CustomVue Wavefront PRK or Epi-LASIK

By | Customvue, Epi-lasik, Laser vision correction, LASIK, PRK, Refractive Surgery, VISX | No Comments

There are a number of things to consider when deciding whether or not to have laser vision correction and where to have it done.

It can be helpful to have more than one refractive assessment to meet staff, see the facility, and learn about the services offered at that center.  Most importantly a thorough refractive assessment will determine if laser vision correction is safe for you.  There are many factors that are considered during an assessment including corneal thickness, corneal shape, how high your correction is, and general medical and eye health issues.  More information about these factors can be found in Dr. Anderson Penno’s book Laser Vision Correction: What You Need To Know  available at: http://www.amazon.com/Laser-Vision-Correction-What-Need/dp/143926497X/ref=sr_1_4?s=books&ie=UTF8&qid=1296107050&sr=1-4

It is important to choose a surgeon you are comfortable with and a procedure that is right for you.  When choosing a procedure the laser vision correction options fall into flap and no-flap categories.  Flap procedures include Intra-LASIK (called I-LASIKby AMO)  and LASIK.  These treatments both involve the creation of a corneal flap and carry a higher risk than surface treatments.  No-flap surface treatments include PRK, Epi-LASIK, and LASEK.  For surface treatments the epithelium layer is removed and the laser is applied to the surface of the cornea.  Many refractive surgeons believe that a wavefront treatment will be most effective if used in combination with a surface laser vision correction rather than a flap treatment.  The reason is that the corneal flap created by LASIK or Intra-LASIK may induce additional vision abberations that may diminish the benefit of a wavefront treatment.

Wavefront laser vision correction involves measuring the higher order aberrations that are individual to each eye and then using that data to create an individualized laser vision correction.  The analogy that is often used is that for nearsighted eyes the cornea is shaped like a basketball that is too steep, for farsighted eyes the basketball is too flat, and in astigmatism the cornea is shaped like a football.  A standard laser vision correction will reshape the cornea into a sphere (basketball) that is just right.  Wavefront treatments will then smooth out any imperfections that may be present on the surface to produce maximum vision results.

There are many studies that indicate the benefits of wavefront treatment in maximizing uncorrected vision.  Due to the number of different laser manufacturers, variety of treatments (flap, no-flap, etc.), surgeon differences, and individual healing responses it is difficult to make an exact quantification of the benefits of wavefront treatments compared to standard laser ablation or between wavefront capable lasers.  Reliable scientific studies can be found in peer reviewed studies such as those available at the US National Library of Science online database:http://www.ncbi.nlm.nih.gov/pubmed  TheVISX S4 IR Customvue system is the most widely used custom wavefront system used in North America.  It has benefits of iris recognition and cyclotorsion (rotational) adjustment that enhances accuracy.  It also features a variable repetition rate and variable spot size which reduces heat generation and allows for a very refined corneal reshaping capability.

Wavefront custom laser vision correction can enhance visual results and is one of the factors that should be considered when deciding whether to have laser vision correction and where to have it.  For more information or to book a refractive consultation with Dr. Anderson Penno, contact Western Laser Eye Associates.