Tag Archives: PRK

Scleral Lenses – An Old Dog With New Tricks

Eye with keratoconusScleral lenses have been around for over 100 years. Until the new gas permeable lens materials were developed patients could only wear scleral lenses for a few hours a day. With the highly oxygen permeable lens materials now in use, patients can comfortably wear these lenses all day. Scleral lenses are most commonly used to treat eyes with irregular corneas such as keratoconus and post surgical eyes (usually following corneal transplant surgery or related to complications from refractive surgery). Another common use for scleral lenses is in the special effects industry where they are used to protect the cornea and/or to give the eye an exotic appearance.

What Is A Scleral Lens?

Scleral lenses are large contact lenses that rest on the sclera (white part of the eye) with the remainder of the lens vaulting over the cornea. Tears are trapped between the lens and the cornea allowing sclerals to treat irregular corneas. The average soft contact lens has a diameter of about 14 mm whereas scleral lenses typically have a diameter exceeding 14.5 mm. 

How Are Scleral Lenses used?

At Total Eye Care Dr. Driscoll has  used scleral lenses to treat many conditions such as irregular astigmatism, keratoconus, high myopia, dry eye syndrome, and complications related to LASIK and PRK. Because of their size, sclerals are quite comfortable. Patients often report the comfort being similar to that of a soft contact lens. Most patients with irregular corneas will see better with a scleral lens than with glasses. 

Below is a good video that shows how scleral lenses are cared for and how to insert and remove them.

Good Morning America Investigates LASIK Complications

Good Morning America reports that the American Academy of Ophthalmology states 90% of patients achieve 20/20 vision following laser vision correction.  What the AAO report does not address is that 20/20 does not mean that the patients have a good quality of visual acuity.  The Good Morning America Video (video at the end) interviews both satisfied and unsatisfied patients.  Some patients complain of a worsening of their dry eye symptoms, halos or shadows, glare or starbursting, poor night vision, reduced contrast or simply uncorrectable blurry vision.  The vast majority of the patients that have had LASIK or PRK are happy with the result.   However, laser vision correction is not reversible and some of the resultant problems from refractive surgery are not resolvable.

Options available to patients that are not happy with their surgical result, of course depend on the symptom.  Some of the options available to patients are:

Post Surgical Contact Lenses

These special contact lenses are available as soft contacts, as gas permeable lenses and as a combination soft/gas permeable.  Post refractive surgery contact lenses are usually used when a patients vision can not be corrected by additional surgery, glasses or regular contact lenses because their corneal surface has become slightly irregular or distorted.  The symptoms may include, blurry vision, halos and shadows.

Dry Eye Syndrome

The most common complaint following refractive surgery is dry eyes.  Most often the dryness improves two to six months following surgery.  Ocular dryness can also cause blurry vision.  Should the dryness not improve there are numerous solutions to improve patient comfort and it is worth seeking help from an eye doctor that is familiar with treating dry eye syndrome.

Glare and Poor Night Vision

Often glare, halos and night vision problems are due to large pupils and/or uncorrected refractive error.  Night driving glasses will usually help patients that are still a little nearsighted following refractive surgery.  Treating the glare is little more difficult.  Glare often improves with time, however a medication called Alphagan has been known to improve night glare symptoms by causing the pupil to constrict slightly.  Alphagan may contribute to the ocular dryness, however.

Know Your Vision Correction Options

LASIK and PRK are good procedures and can greatly improve one’s quality of life.  Prior to taking the refractive surgery plunge patients should thoroughly research their options.  In an upcoming article I’ll cover the alternatives to refractive surgery.

At Total Eye Care we offer all of the refractive surgery and non surgical vision correction options available and we pride ourselves on giving our patients an objective opinion of all of their choices.  It is important for our patients to be well educated on the pros and cons of each option so that they can make an informed decision.

Check out the video below from the Good Morning America’s investigation on LASIK, it offers a balanced report on refractive surgery.

LASIK – Is It Safer Than Contact Lenses?

It’s all over the radio these days a LASIK surgeon touts “some experts believe LASIK is safer than contact lenses”. In reality this is a difficult statement to backup properly, given that we are really comparing apples to oranges. Why is this comparison difficult? Comparing LASIK to another refractive surgery procedure, such as PRK, is rather straight forward because the complications are similar for both procedures and the opportunity for complications is essentially nil after the patient is stable, typically 6 months to a year after surgery. A contact lens wearer, on the other hand, has a lower complication rate. When compared to LASIK or PRK contact lens complications are less severe and less frequent, however, a contact lens wearer’s potential for complications will last as long as the patient is wearing their lenses, often for decades.

Both LASIK and contact lenses are safe and in our office we utilize both techniques, choosing which is best for the patient. It is our practice to discuss all of the refractive options with our patients. We weigh the risks and benefits of each option before proceeding.

As a practical matter the incidence of vision threatening problems in compliant contact lens wearers is very small. When a patient does have a problem, it typically manifests itself as a red eye usually resulting from poor care or not replacing their contacts as often as recommended. It is exceedingly rare for a contact lens related red eye to cause a patient to require surgery to resolve the problem.

This prompts me to ask “what does the research say”. In my mind that’s what matters. Let the studies show us which is safer. The most important contact lens and LASIK complications are those that have resulted in a loss of vision and therefore that is the best criteria to compare LASIK versus extended wear contact lenses. A 2005 study including almost 5,000 patients followed over a 1 year period showed that 30 day Ciba Night & Day contact lens wearers, experienced an overall rate of presumed infiltrative keratitis (a type of corneal ulcer) of 0.18%. Of those experiencing keratitis 0.036% resulted in a loss of vision and 0.144% experienced keratitis without vision loss.

Numerous studies published in 2005 and 2006 indicated a complication rate for LASIK, resulting in a loss of best corrected vision, ranging from 0.6% to 7.0%.

Given the facts outlined above, I feel it is doing patients a disservice to state or imply that refractive surgery is as safe or safer than silicone hydrogel contact lenses. Both LASIK/PRK and silicone hydrogel contact lenses have come a long way in reducing both the rate and severity of complications and in looking at the numbers both are safe.

I still believe LASIK and PRK are good options for patients. I, in fact, have had LASIK and at our office it is still one of the refractive options we present to our patients. However, the research does not support the statement that refractive surgery is as safe as contact lens wear nor should it be promoted as such.

Technorati Tags: Extended Wear, Laser Vision Correction, , , ,