Category Archives: Surgeon

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.

 

Bionic Lens: can everyone have perfect vision?

By | Food for thought, Keratectomy, Laser Eye Surgery, Laser vision correction, LASIK, Optometry, Photorefractive, PRK, Refractive Surgery, Surgeon | No Comments

There has been a lot of talk recently about the “Bionic Lens” which has been invented by an optometrist from British Columbia.  CBC news recently ran a story about the new lens implant.  According to this news story, “Pending clinical trials on animals and then blind human eyes, the Bionic Lens could be available in Canada and elsewhere in about two years, depending on regulatory processes in various countries.”  If there are problems in the back of the eye involving the retina, such as macular degeneration, this lens would not be able to correct the poor vision.  So vision improvement using this lens would be helpful to people who can correct their vision with glasses or contact lenses.  At this time vision correction surgeries are able to allow people to see as well without glasses or contact lenses as they do with their eyewear – for most people they would not be expected to see better than their best corrected vision.

The photographs of the lens looks similar to some of the designs currently available for intraocular lens implants used most frequently in cataract surgery.  It is not clear from the news reports what makes this lens design so revolutionary.  There do not appear to be reports yet in the peer reviewed literature which would fit with the reports that animal and blind human eye trials have not been done yet.  These steps are needed to prove that the lens is safe before proceeding to sighted human eye studies.  In people younger than 45 years old, lens replacement surgery is not usually recommended due to the fact that reading glasses may be required unless a multifocal lens is used or unless one eye is left near-sighted for reading (monovision).

The most common treatment for reducing dependence on glasses in this age range is laser vision correction.  The original photorefractive keratectomy (PRK) techniques were developed in the 1980’s and have been refined over the following decades.  This is still a reliable way to improve uncorrected vision in people who meet the safety criteria including thick enough corneas, prescriptions that are within the range of correction, healthy eyes, and no health problems that might cause problems in healing or risk of infection (such as immunosuppression).  For people younger than 45 but with high corrections outside the range of laser vision correction the implantable contact lens is usually the next option.

Will the Ocumetrics Bionic Lens replace laser vision correction and standard lens implants used for cataract surgery?  The reports are optimistic according to the news stories, but the proof will be coming in the next few years as preliminary studies and then sighted human eye studies are done.  There is a lot of excitement about this new lens implant and if it lives up to expectations it is possible that it may become a common option for vision correction in the future.  For now though, laser vision correction is the first option to consider as a way to reduce the need for glasses or contact lenses.

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.