An Advanced Microscope for the Anterior Segment

Surgeons discuss the enhanced visualization, red reflex, depth of focus, and surgical guidance of the Proveo 8.

To better understand how the Proveo 8 ophthalmic microscope benefits practitioners, we asked two leaders in the field who are using this new technology. Iqbal “Ike” K. Ahmed, MD, at the University of Toronto has been using the Proveo 8 in the hospital setting for patients with both anterior and posterior segment pathologies. James A. Katz, MD, of the Midwest Center for Sight in Chicago, Ill., has used the new microscope in his ambulatory surgery center for complex cataract lens implants and corneal surgery.

From an anterior segment perspective, what is the difference between the Proveo 8 and earlier microscopes?

Dr. Katz: The difference is the visualization. In anterior segment surgery, we want to clearly see the cornea, anterior chamber, lens, and lens capsule, and visualization with the Proveo 8 is superior to my previous microscopes.

The Proveo 8 has excellent lighting, sharpness, and contrast. I get a much better view and more accurate guidance, which translate into greater efficiency. When we can see more detail, we are less likely to have complications. This is especially true in difficult cases, such as those with corneal scarring or dense cataracts, which make visualization more difficult. When I use the new microscope, I really see what I was missing.

Dr. Ahmed: It’s all about visualization, and the Proveo 8 is optimally designed to enhance visualization. The scope has two major areas of improvement over the previous generations: 1) enhanced visualization of the entire cataract procedure, not just during capsulorhexis, but also during lens placement; and 2) significant improvements in red reflex.

Even with microscopes that have good red reflex, visualization for the entire case may not be optimal. For example, in cataract surgery, although there may be a very nice red reflex for capsulorhexis, after we have hydrated the lens and during lens removal, clarity is not always as high as we would like it to be. This is multifactorial and related to the design of the illumination system as well as the optical path. The Proveo 8 allows us to see all steps of the procedure clearly from beginning to end. There is a noticeable difference with this microscope.

What is your experience with the red reflex of the Proveo 8?

Dr. Ahmed: Each optical pathway in the Proveo 8’s all-LED illumination is oriented at zero degrees, which makes the red reflex consistent. It is a top-tier microscope for red reflex, which is critical for a great deal of anterior segment work. The surgeon can adjust the size of the red reflex enhancer to allow for differences in pupil space and variability in the eye position. The red reflex is brilliant and immediately observable with the scope — exactly what we need and expect from a modern microscope.

Dr. Katz: The view produced by the red reflex in the Proveo 8 ensures high contrast and exquisite resolution for clear, sharp images. The system of four coaxial LED lights that creates the red reflex is a hallmark of this microscope. It provides a better reflex because the coaxial lighting angle is optimized for the red reflex. Unlike other microscopes, even as the eye moves during surgery, the four LED lights still emit at zero degrees, so we do not lose the consistency of the red reflex.

Does the enhanced depth of focus of the Proveo 8 help anterior segment surgeons?

Dr. Ahmed: In cataract surgery, focus and centration are essential elements of visualization. The ability to maintain focal clarity in larger depth is very exciting. The Proveo 8 enhances depth by 40% by differential apertures between the surgeon’s two eyes. Even independent of any other feature of this microscope, this is a valuable advantage.

When I work in the anterior chamber, I like to set the magnification fairly high so I can see my work and move instruments across the field without continually refocusing. The Proveo 8 has allowed me to refocus even less. The change is intuitive — during surgery, you do not notice that you have a reduced need to refocus.

Dr. Katz: Although the anterior chamber is a small area, when we focus with many ophthalmic microscopes, we often can have depth issues from the cornea to the lens. With better depth of focus in the Proveo 8, a larger area of the eye is constantly in focus. Because we do not have to continually focus, we can concentrate on the surgery at hand with greater efficiency and less distraction.

You both use the IOLcompass system. How has it impacted your cataract procedures?

Dr. Katz: IOLcompass places a virtual image on the eye, which the surgeon can see through the ocular. This helps guide the centration and alignment of toric lenses. It can be used to create limbal relaxing incisions as well. The image registers with the eye and allows the surgeon to track its position.

Before I began using IOLcompass, I manually marked each eye before the procedure to reduce the effect of cyclotorsion. Manual markings are inherently less precise than the virtual image guidance produced by IOLcompass. I think this precision may improve outcomes, and it certainly saves the surgeon time compared with placing manual marks.

Dr. Ahmed: Surgical guidance is a nice workflow enhancement. The IOLcompass tool helps the surgeon provide on-the-table assessment and alignment, taking IOL positioning to the next level. We need more data to know if it makes a difference clinically, but it is a valuable feature in terms of workflow and ease of use.

Do you use the integrated slit lamp and keratoscope on the Proveo 8?

Dr. Ahmed: I have used the keratoscope, which gives me a nice sense of the corneal astigmatism and axis. It is a helpful additional tool to have on hand for some limbal relaxing incisions or toric alignments or for suturing corneal tissue.

Dr. Katz: The slit lamp provides a three-dimensional view of the corneal layers – for example, to adjust corneal sutures. The keratoscope allows me to view and estimate the residual astigmatism during corneal procedures.

How would you rate the advanced assistant scope on the Proveo 8?

Dr. Ahmed: Working every day in a teaching environment, having a fully optimized assistant scope makes a dramatic difference. Surgeon and assistant have the same stereoscopic view and enhanced red reflex with the Proveo 8, as does the HD video screen. The camera system records the same view as well, and the integrated open architecture allows the use of any third-party camera — another advantage.

Dr. Katz: In microscopes with a beam splitter, each set of oculars gets 50% of the light, driving down contrast and resolution. When I attach an assistant scope or a three-dimensional camera to the Proveo 8, each receives 100% of the light. •

James A. Katz, MD, is one of five board-certified ophthalmologists at the Midwest Center for Sight. He is a cornea, cataract, and laser eye surgery specialist who performs a range of refractive surgical procedures, including advanced LASIK, corneal transplants, DSEK, Intacs, and cataract surgery. In addition to refractive surgical procedures, Dr. Katz also provides routine eye exams, preventive eyecare health, conducts studies, and treats all medical eye conditions.

Iqbal “Ike” K. Ahmed, MD, is an assistant professor at the University of Toronto, where he also serves as the research fellowship director in the department of ophthalmology and as director of the glaucoma and advanced anterior surgical fellowship. He is also a clinical professor at the University of Utah. Surgical management of glaucoma, the complex cataract, and management of cataract and intraocular lens complications are his areas of subspecialty expertise.