We noticed you’re blocking ads

Thanks for visiting CRSToday. Our advertisers are important supporters of this site, and content cannot be accessed if ad-blocking software is activated.

In order to avoid adverse performance issues with this site, please white list https://crstoday.com in your ad blocker then refresh this page.

Need help? Click here for instructions.

Cataract Surgery: Focus On Surgical Microscopes | Nov 2010

Visualizing Premium Cataract Surgery

The Lumera has superb optics and is ergonomically comfortable, but the biggest benefit is the new lighting.

Premium cataract surgery encompasses the patient’s experience, the refractive nature of the procedure, and the premium lens implanted in his or her eye. Most of all, however, premium means performing the highest-quality and safest surgical procedure possible, which requires exquisite visualization throughout phacoemulsification. In premium cataract surgery, every step is crucial. For example, a reproducible and well-constructed incision seals well and induces little astigmatism. A round, continuous capsulorhexis will keep the lens optic centered and stable.

Intraoperatively, subtle visual details alert the ophthalmologist to any potential challenges during surgery. Pseudoexfoliative material on the lens capsule may indicate weak zonules. Adherent lens epithelial cells may contribute to capsular fibrosis and a postoperative shift of the IOL. Tears in Descemet’s membrane may reveal a corneal incision prone to leakage. Detecting all of these subtleties while operating requires the excellent visualization provided by the optimized optics and lighting from the surgical microscopes.

The first time I used the Opmi Lumera 700 (Carl Zeiss Meditec, Inc., Dublin, CA) microscope, I was hooked. The optics are superb, and the ergonomics are very comfortable. The most striking benefit, though, is the new lighting. Using a combination of paraxial and coaxial lighting, the Lumera gives a beautiful red reflex throughout the surgery. The xenon light source provides the same spectrum of pure white light as natural sunlight. When I perform live surgery at national ophthalmology meetings, I choose the Lumera because I know that visualization will be excellent for me, and the audience will enjoy seeing the fine details of surgery.

Traditional surgical microscopes offer paraxial lighting such that the microscope’s light is positioned a few degrees off axis from the oculars. The result is good depth of field, but the red reflex, which is critical in ocular surgery, is limited to a small range. Coaxial lighting involves adding a light source directly in line (a zero-degree offset) from each of the surgeon’s oculars. By combining coaxial with paraxial lighting, the surgeon has a continuous red reflex with good depth perception throughout the surgery, even with ocular rotation.

Premium IOLs
Inaccurate position of IOLs, particularly premium designs, can compromise outcomes. The constant red reflex of coaxial illumination provides the view surgeons need.

Toric IOLs must be placed at the steep corneal meridian to effectively neutralize astigmatism. On the optic of the toric IOL, there are markings indicating the meridian of astigmatic correction. With coaxial illumination, surgeons can easily view these markings and align them with similar markings on the cornea.

The multifocal IOLs have concentric rings that must be aligned with the pupil and visual axis to provide optimal vision. Patients having cataract surgery under topical anesthesia can be asked to look between the two coaxial lights, directly in line with the surgeon’s view. The IOL can be shifted toward the center of fixation to align the microscope light’s reflection and Purkinje images. Using this technique, I find that the multifocal IOLs tend to be very well centered, most within a fraction of a millimeter of ideal. Diffractive lenses often have central optical zones of 1 mm or less, and the proper alignment and centration of these multifocal IOLs is critical for optimal visual results.

Challenging Case
Sometimes, surgeons encounter challenging cases involving patients with complex ocular histories. Visualization of details becomes important. Figure 1 shows creation of the capsulorhexis in an eye that has undergone eight-cut RK and later LASIK. Due to the excellent red reflex from the coaxial lighting, all of these details are clearly visible.

Premium cataract surgery (Figure 2) requires meticulous attention to detail in order to provide a safe and visually rewarding procedure, and that begins with excellent visualization.

Uday Devgan, MD, FRCS(Glasg) is in private practice at Devgan Eye Surgery in Los Angeles, Beverly Hills, and Newport Beach, California. Dr. Devgan is also chief of ophthalmology at Olive View UCLA Medical Center and an associate clinical professor at the Jules Stein Eye Institute at the UCLA School of Medicine. He is a speaker for Carl Zeiss Meditec, Inc. Dr. Devgan may be reached at (800) 337-1969; devgan@gmail.com.

Advertisement - Issue Continues Below
Publication Ad Publication Ad
End of Advertisement - Issue Continues Below