Category Archives: Laser Eye Surgery

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.

 

Vision & Vitamins: Can supplements prevent nearsightedness?

By | Cataracts, Diabetes, Laser Eye Surgery, Laser vision correction, Ophthalmologist, Ophthalmology, Opthamologist, Optometry, science, Vision & Vitamins | No Comments

Nearsightedness (also called myopia) affects from 20% to 50% of North Americans and up to >80% of some populations in Asian countries.  The need for nearsighted correction with glasses or contacts can run in families and is more likely to be present if both parents are myopic.  The natural course of nearsightedness is that it can start in childhood or young adulthood and continue to progress up to age 20 or in higher corrections into the 30’s.

There are some conditions that may be associated with nearsightedness so regular eye examinations are recommended even if the prescription has stopped changing.  Nearsighted people and parents of nearsighted children are of course interested in finding ways to slow or prevent the progression of myopia.  There has been conflicting scientific evidence to support the relationship between reading and near work and higher myopia, however there was no proven association between nearsightedness and computer work.  There has also been some evidence to suggest that more time spent in natural light (outdoors) can help to reduce the increase in prescription over time.

There have been a number of studies to try and find a link between nutrition and nearsightedness and to this date there has not been anything proven to prevent natural progression of myopia in children and adults.

It is important for anyone affected by nearsightedness to have regular eye examinations with and optometrist or ophthalmologist even if the prescription isn’t changing.  Sudden shifts in the degree of nearsightedness can indicate conditions like diabetes or cataracts if changes are happening at an older age.

Correcting nearsightedness is usually involves using glasses or contact lenses.  Laser vision correction can be considered after the prescription has stabilized for at least 2 years.

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.

Happy Birthday PRK!

By | Laser Eye Surgery, Laser vision correction, LASIK, PRK, Refractive Surgery, Uncategorized | No Comments

Photorefractive keratectomy (PRK) is the original laser vision correction surgery that was first performed in the US in the 1980’s and on June 12, 1990 at the Gimbel Eye Centre in Calgary Alberta Canada.  In the 25 years that followed PRK first gained in popularity over radial keratotomy (RK) in which incisions were made in the cornea to flatten the surface of the eye for treatment of nearsightedness.  PRK has the advantage of precision laser modification of the corneal curvature using the excimer laser.  The excimer laser was originally intended for industry and manufacturing but when a curious researchedr took some leftover Thanksgiving turkey back to to lab laser vision correction was born.

PRK quickly replaced RK as a more stable and precise way to eliminate the need for glasses or contact lenses.  As the search for improvements continued into the 1990’s the older technology of cutting a corneal flap was combined with the excimer laser reshaping in a treatment that was first called “FLAP & ZAP” and later laser in situ keratomileusis (LASIK).  LASIK quickly overtook PRK as the most popular laser vision correction method into the early years of this century due to the faster healing the flap allows.  Throughout this time PRK remained a trusted method and was considered safer than LASIK for thinner corneas and for athletes and people with occupations that might risk eye injury due to the risk of a LASIK flap shirt.

As the early 2000’s progressed a new and difficult to treat complication became recognized – corneal ectasia. Ectasia after LASIK is uncommon but can result in an unstable corneal surface that is analgous to a weak spot in a tire, which makes the surface of the eye bulge out and become irregular over time.  There has been a lot of debate about ectasia after LASIK, but many eye surgeons believe that PRK may be a lower risk for this specific problem due to the fact that the cornea is not disrupted as deeply as compared to LASIK.  The LASIK flap does not leave the eye but once it is cut it may no longer contribute as strongly to the corneal structure.  This weakening in addition to a number of other risk factors appears to play a role in post LASIK ectasia.  All the while PRK has continued to be offered as an option for laser vision correction in particular for people who might not qualify for LASIK.

In the past few years many surgeons around the world have moved “back to the surface” and choose not to cut corneal flaps in order to affect the smallest amount of corneal tissue needed to improve uncorrected vision.  Advances over the last quarter of a century since PRK was first done include significant advances in excimer laser technology including iris recognition, cyclotorsion adjustments, and the ability to do individually customized treatments using wavefront technology.  In addition, improved bandage contact lenses and medications have been developed to reduce post-operative discomfort and risk for haze following PRK.

PRK turns 25 this year in Canada and is still going strong!

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

Vision & Vitamins: Ginkgo Biloba, Glaucoma, and Macular Degeneration

By | Epi-lasik, Epilasik, Eye health, FDA, Food for thought, Ginkgo Biloba, glaucoma, Health Canada, Laser Eye Surgery, Laser vision correction, macular degeneration, Mayo Clinic, Ophthalmologist, Ophthalmology, Opthamologist, Optometry, Pubmed, Refractive Surgery, science, Uncategorized, Vision & Vitamins | No Comments

Vitamins and natural herbs have become more and more popular for alternative treatment as additional treatments for medical conditions.  Ginkgo Biloba has been used for centuries as a traditional treatment which may help blood flow to the brain and aid in treatment of dementia or Alzheimer’s disease.  It might help treat leg pain that results from blood vessel disease, and there is some suggestion that ginkgo biloba might also help PMS symptoms, depression, multiple sclerosis, and ADHD.  Ginkgo Biloba is extracted from the leaves of the Ginkgo Biloba tree.  As far as vision and eye health are concerned, it is possible that Gingko Biloba might be helpful to eye health but as with many natural products the scientific studies show some favorable and some unfavorable results.

There are some scientific studies that have been reported in the peer reviewed literature which is a data base of articles that have been reviewed by scientists with expertise in the particular field of study before the article is allowed to be published.  Peer review helps to make sure that studies are done in a way that will provide strong statistical evidence for or against a specific area of study.  The most powerful studies are randomized and double-blinded which means the researcher and the subject who is taking the supplement do not know if it is the actual supplement or a placebo being taken.  The “placebo” effect has been well studied and up to 30% of people taking a fake pill who are told it will have beneficial effects will report that it helps whether or not there is any measurable effects.  By double-blinding and using large and randomized numbers of subjects the results will show with more confidence that a particular supplement is helpful or not for a specific condition.  Because there are a lot of different conditions that are being studied, so far there are only a few published peer reviewed scientific studies that have been done to find out if Ginkgo Biloba is good for your eyes.

According to the Mayo Clinic there is some scientific evidence suggesting that Ginkgo Biloba may be helpful in preventing worsening in age related macular degeneration which can lead to central vision loss, but there is little evidence to suggest it might be helpful for treatment of glaucoma.  In the peer reviewed literature there are a few studies including this 2012 study by Cybulska-Heinrich, Mozafferieh and Flammer that suggests supplementation with Ginkgo Biloba might be helpful in addition to traditional medical treatment in cases that are not responding as well as needed to these traditional treatments.  They suggest that antioxidant effects along with a variety of other effects on blood flow might be responsible for the beneficial effects of supplementation with Ginkgo Biloba.  The American Academy of Ophthalmology reported there was a single small randomized trial that showed promise for using Gingko Biloba to slow macular degeneration.

A commonly reported dose of Ginkgo Biloba is a standardized extract, standardized to 24% flavone glycosides and 6% terpene lactones starting at 40 milligrams of that extract three times daily, but there does not seem to be enough evidence in the scientific studies to prove the most effective doses for a specific condition.  Risks and side effects of Ginkgo Biloba supplements include headaches and dizziness, bleeding, and other side effects.  If you are on a blood thinner or aspirin, or are on other medications you should talk to your pharmacist and/or doctor to make sure that there won’t be dangerous interactions.  There is also some question about the quality of the products in some cases and as with all supplements it is important to be sure you are getting a high quality product.  In Canada a DIN or NPH number can be found on products that have been reviewed by Health Canada.  In the US the FDA does not require approval of supplements before the product is marketed but does collect information on adverse events.  The other thing to consider is the cost of a product like Ginkgo Biloba versus the proof that it will be helpful for your health.

Whether you already had LASIK, Intralasik, EpiLasik, PRK, wear glasses or contacts, reading glasses or no glasses at all you should be sure to get regular checks with your eye care specialist (optometrist or ophthalmologist) in order to optimize your vision for the rest of your life.  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.

Vision & Vitamins: eat your carrots!

By | Eye health, Food for thought, Laser Eye Surgery, Laser vision correction, Ophthalmologist, Refractive Surgery, Uncategorized, Vision & Vitamins | No Comments

Is the old wives’ tales about eating carrots fact or fiction?  Carrots are high in beta-carotene which the body converts to vitamin A.   Carrots also provide vitamin C, iron, calcium and fiber.  Carrots and other foods rich in vitamins C and E, zinc, lutein, zeaxanthin, and omega-3 fatty acids DHA and EPA benefit eye health and general health, as hown by the the Age-Related Eye Diseases Study (AREDS), funded by the National Eye Institute. These nutrients are linked to lower risk for age related macular degeneration (AMD) and cataracts.

The myth that eating carrots can improve your vision seems to have been made popular during World War II when a propaganda campaign was run to convince the Germans that Royal Air Force pilots had superior night vision due to eating carrots.  This campaign was started to cover up the fact that the pilots were using a secret new radar technology that allowed them to strike under cover of darkness.  According to the Smithsonian Magazine and the World Carrot Museum (a virtual museum about all things carrot) RAF fighter pilots told newspaper reporters that carrots improved their night vision and it was picked up in the popular press of the time.

In reality carrots and other deeply colored fruits and vegetables do contain vitamins that are important for healthy eyes, but in most developed countries vitamin A deficiency is rare so eating carrots is not likely to result in a noticeable improvement in vision.  It is possible that in ancient societies there may have been improvements in vision from eating carrots in areas where vitamin A deficiency may have been common due to seasonal changes in diet.

Eating too many carrots will turn your skin orange but is not likely to harm you.  According to the USDA 1 cup of chopped carrots contains 0 fat, 0 cholesterol, 88mg sodium, 12gm carbohydrate (4gm dietary fiber, 6 gm sugar), 1 gm protein, 428% daily recommended Vitamin A, 13% daily recommended Vitamin C, 4% daily recommended calcium, and 2% daily recommended iron.  There are some reports that pesticides can build up in the skin so peeling carrots may be a healthier option.

In general it is good advice to –  eat a little bit of everything and not too much of any one thing.  As it turns out the stories about carrots are both fact and fiction!

 

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

 

Blepharitis & PRK/LASIK

By | Laser Eye Surgery, Laser vision correction, LASIK, PRK, Refractive Surgery | One Comment

If you are thinking about having PRK or LASIK laser refractive surgery you should be familiar with the common conditions that can cause problems after surgery.  Most people who have PRK or LASIK are very satisfied.  For the small percentage of people who have problems following laser vision correction, dry eye is one of the most common complaint.

Dry eye can be a complicated problem, called “ocular surface disease” by eye care professionals.  Dry eye is not as simple as not enough tears.  A normal tear film is like oil and vinegar salad dressing – the oil, mucous, and water components need to be in the proper proportions and also mixed properly to form an emulsion.  An emulsion is what happens when you shake your oil and vinegar salad dressing.

Blepharitis is a condition that causes plugging of the oil glands that have openings just inside the upper and lower eye lashes.  Blepharitis can also cause redness and inflammation along the eye lashes and mattering of the lashes.  Without the proper oils the tear film does not wet the eye surface as well.  The mattering of the lids can also lead to a poor quality tear film which causes dry eye symptoms.

Blepharitis treatment is like treating dry skin or any other chronic condition.  Treatment of blepharitis means a change in habits – the treatments need to be done as part of your daily routine on an ongoing basis.  Daily warm compress with mild pressure on closed lids with a warm wet cloth for 3 to 5 minutes twice per day is the most important treatment.  The warmth will encourage the oils to flow, the mild pressure can soften and lift off matter, and the moist cloth will help lift off debris.  Other treatment are gently washing the lids with dilute baby shampoo 1:10 or with a lid care pad available at pharmacies.

The link between blepharitis and PRK or LASIK is that after surgery, without glasses or contact lenses, the eye is more exposed to wind and evaporation.  If you wear glasses you know that there moist air trapped between your eye and your glasses because when you go out in the cold the glasses fog up.  Even contact lenses can provide a barrier from evaporation.  Once the surface is exposed on a daily basis, people with blepharitis might find their eyes feel more dry than before PRK or LASIK.

Before you have laser vision correction your eye care provider will assess pre-existing conditions like blepharitis and give you advice about treatment of these conditions.

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