Archive for May, 2013

Over 20 Years of Laser Vision Correction at Bochner Eye Institute

Monday, May 20th, 2013

Laser vision correction has been the most common and successful refractive procedure in North America over the past 2 decades. Clinical outcomes have been excellent when respecting the indications and contraindications of the procedure, utilizing advanced technology, surgical competence, and careful follow-up care. After more than 20 years of performing laser vision correction at the Bochner Eye Institute, this is my top list of factors to ensure outstanding patient outcomes:

1.    Rule out keratoconus and pellucid marginal degeneration (PPMD)
LASIK is a contraindication in eyes with keratoconus and PPMD. Creating a flap in a structurally weak cornea can lead to cornea ectasia. There are many clinical signs of keratoconus and PPMD but the most helpful involve topographical and pachymetry imaging utilizing Pentacam technology. Findings of clinical value include: A. Inferior to superior steepening of greater than 1.6 D; B. Central steepening of 48 D or greater; C. Elevation of posterior cornea of 17 microns or greater; and D. Area of corneal thinning that corresponds to the area of anterior and posterior corneal elevation.

2.    Rule out dry eyes
Dry eye syndrome especially with a superficial punctate keratopathy can delay the visual recovery. Patients with severe dry eyes should not undergo laser vision correction. Patients with mild to moderate dry eyes if treated aggressively preoperatively may be satisfactory candidates for LASIK. Dry eye treatments may include preservative-free artificial tears, oral omega fatty acids, lubricating gels or ointments, Restasis drops, hot compresses to the lids if plugged meibomian glands, or the Lipiflow procedure. Bochner Eye established a Dry Eye Clinic to try to rehabilitate patients and enhance their comfort and visual function.

3.    Femtosecond flap creation
Femtosecond technology has revolutionized the safety of LASIK. The creation of a thin flap that has the same thickness in the centre and periphery reduces the risk of serious complications. Unfortunately discount laser centres continue to utilize a mechanical microkeratome that exposes patients to significantly higher risks. Femtosecond lasers have eliminated the risks associated with mechanical micrkeratomes, which include: button holes, free flaps without a hinge, partial flaps, and irregular flaps.

4.    Surgical competence
Although excimer lasers and the creation of femtosecond flaps have added some automation to the procedure there are many steps that require surgical care. A skilled surgeon will insure proper centration of the corneal flap, a dry corneal bed prior to and during the excimer ablation, satisfactory patient fixation during the excimer ablation, minimal irrigation beneath the flap, and careful repositioning of the corneal flap.

5.    Postoperative care
Although complications are uncommon using advanced technology, the identification of any early complications and proper management can insure an excellent outcome. Most early complications include visually significant striae, diffuse lamellar keratitis, and an epithelial defect. The rare complications are microbial keratitis and corneal ectasia. If the refractive outcome is not satisfactory then an enhancement can be performed. It is typically best to wait at least 4 months for an enhancement to ensure refractive stability.

6.    Maintenance and Calibration of Equipment
A laser centre must insure proper calibration and maintenance of all the equipment. Excimer laser and femtosecond technology require frequent maintenance checks to be sure optimal function. A dedicated technical staff that is experienced with daily calibration of the equipment and ensures regular maintenance is critical to achieving outstanding results.

7.    Communication between the surgeon and comanging doctor
Communication between the surgeon and comanging doctor about any patient concerns or general education concepts is vital for optimal care. At the Bochner Eye Institute, communication can be accomplished with a phone call, email, or fax.

8.    Ability to customize excimer laser ablations using either topographically-linked, wavefront-guided, or wavefront-optimized techniques
The surgeon should be able to choose the right technology for the right patient to achieve the best possible outcome. Technology continues to advance with more sophisticated treatment options. When patients have any corneal irregularity, a topographically-linked ablation is the treatment of choice to smooth the corneal surface. Eight Pentacam images, representing 20,000 data points per image, are transferred to the excimer laser system and a customized laser ablation is performed. In addition, we now have the ability to centre the excimer ablation over the line-of sight and not the centre of the pupil using a topographically-linked ablation. We all recognize that a patient’s refractive error is aligned with the line-of sight, which is not necessarily the centre of the pupil. By performing the laser ablation over the line-of sight we can enhance the refractive accuracy especially in hyperopic patients.

9.    Presbyopic Considerations
Understanding the patient’s lifestyle can allow one to customize the treatment. There are many options for the correction of presbyopia including reading glasses, monovision LASIK, KAMRA or other corneal inlays, monovision with an aspheric implant, or multifocal implant with refractive lens exchange. There are advantages and disadvantages to each option. Factors that can influence a presbyopic decision include the value of stereoscopic distance vision and/or stereoscopic near vision, early crystalline lens changes, requirements of night time driving, and personality traits that can play a role in dealing with any visual imperfections. At Bochner we explore all the presbyopic options with our patients before a decision is made for final treatment.

10.    Realistic Patient Expectations
Although over 98% of patients undergoing LASIK at Bochner have excellent  uncorrected visual acuity there are some patients that may require an enhancement. As we all know, laser surgery is performed on human tissue and not on a piece of plastic. As a consequence there can be an individual variation in outcome as a result of the laser interaction with the cornea, as well as a difference in postoperative healing. At the Bochner Eye Institute, laser enhancements are performed at no charge. This life-time warranty has been our policy for over 20 years.

By Dr Raymond Stein

Laser Cataract Surgery using the Catalys Precision Laser System:

Monday, May 20th, 2013

Laser Cataract Surgery using the Catalys Precision Laser System:
Impressions on the first 80 patients treated at Bochner Eye Institute

Laser cataract surgery has surpassed my expectations of enhanced precision, accuracy, and safety. I was cautiously optimistic based on reported clinical results in other countries. Over the past four months, I have been impressed by the sophistication of the machine, the ease of use, the reproducibility, and patient outcomes. The Catalys Laser System has been an exciting and easy procedure for  patients to undergo with a quick visual recovery. Patient satisfaction has been extremely high. Here are my initial clinical impressions:

1.    Perfect Capsulotomy
The capsulotomy is computer programmed to be centred over the visual axis with the creation of a perfect circular opening of 5 mm. Although I am comfortable with traditional surgery using forceps to create a capsulotomy, no surgeon can consistently make a perfect 5 mm opening. By creating a precise capsulotomy the residual anterior capsule overlaps the edge of the implant and holds the lens in position. With a less than perfect capsulotomy the implant can be tilted, or vault forward or backward. Laser cataract surgery with a precise capsulotomy results in a more predictable final resting position of the implant, which improves the refractive outcome and results in fewer induced higher-order aberrations.

2.    Elimination or reduction of phacoemulsification
The Catalys system using 3-D OCT imaging and a femtosecond laser can fragment the nucleus into tiny cubes, which can then be primarily aspirated. In traditional cataract surgery, phacoemulsification is utilized to break the nucleus into tiny pieces prior to aspiration. This phaco energy from a tip that vibrates very quickly (20,000 times per minute) can cause adverse ocular effects. The ultrasound energy can result in corneal endothelial cell loss as well as a higher incidence of cystoid macular edema. By eliminating or reducing ultrasound energy we can preserve the corneal endothelium and hence corneal clarity, both short-term and long-term, as well as reducing the incidence of cystoid macular edema. My experience in the initial cases treated is that the corneas were clearer one day postop, and there was a quicker recovery in terms of uncorrected visual acuity and best-corrected visual acuity. Eighty percent of the initial cases were performed without phaco energy. Of the twenty percent of cases that required some phaco energy the level was significantly reduced compared to traditional surgery.

3.    Correction or reduction of astigmatism
Femtosecond technology can perform precise arcuate corneal incisions to reduce astigmatism. Using real-time OCT imaging the thickness of the cornea is determined. We can plan arcuate incisions at a 9 mm optical zone and at a depth of 80%. We have the option of opening these incisions at the time of surgery or to do this postoperatively to titrate the effect. We are creating these small incisions in anyone with more than 0.50 D of astigmatism. The outcomes have been significantly more predictable than performing limbal relaxing incisions with a blade. These laser arcuate incisions can be combined with a toric implant for higher degrees of astigmatism. Postoperatively, if necessary, the incisions can be opened to enhance the astigmatism correction.

I hope you find these initial impressions on Laser Cataract Surgery of interest. I am delighted to be able to offer this advanced technology at the Bochner Eye Institute. Learn more about Dr Raymond Stein