We asked the four manufacturers of OR microscopes - Carl Zeiss, Leica, M'ller Microsurgery and Olympus - to tell us what's new in these essential and expensive instruments. Here's a review, organized by surgical specialty.

Ophthalmology

• Carl Zeiss's OPMI VISU 150 features an illumination system that provides a stable, bright and rich red reflex even with narrow pupils, according to Carl Zeiss. The scope's apochromatic optics provide improved contrast and reduces the patient's exposure to light. The S88 Floor Stand with magnetic brakes allows for easy positioning, the company says.
• Leica's M841 EBS offers apochromatic optics, double beam red reflex for fundus reflex in all positions and motorized zoom, says Leica. Its assisting surgeon scope offers 100% illumination and stereo view for surgeon and assistant at identical magnification. The scope can be combined with a new electromagnetic stand with a precise, Swiss-made autobalance system, and ergonomic brakes-release.
• M'ller's Hi-R 900 offers apochromatic and residual aberration correction and high red reflex for the surgeon and assistant. Its assistant scope offers assistant and surgeon the same zero-degree viewing and stereo vision and easily swivels laterally for comfortable viewing, according to M'ller. This scope can be combined with an electromagnetic stand, or one with manual controls and a small footprint. M'ller also offers the EIBOS for wide-angle fundus observation during non-contact vitreoretinal surgery.

ENT/Dental

• Leica offers the M400E, a compact scope with a new ergonomic handle that allows one-hand movement. The scope offers a large depth of field with 3-D effect, choice of fine focusing lenses, halogen illumination (xenon illumination is optional), selection of binocular tubes and co-observation tubes, easy-to-use balancing system, long-reach swing arm for positioning and laser adaptability.
• M'ller's Denta 300 is specialized for dental surgery. It provides excellent optics and flexibility in its use, including an eyepiece that can be rotated so the surgeon can look sideways and still remain in a comfortable position, the company says. Other features include integrated camera adapter, five-step magnification changer and fine focus drive. A yellow filter prevents premature hardening of filling materials and a green filter helps to detect blood vessels. M'ller also offers the Spectra, which is specially designed for office-based surgery. Available in several models, the scope is equipped with a large range of accessories.

Neuro/Spine
This is one of the hottest areas for new scopes, as more spine-only centers are being developed.

• Olympus offers MINI (minimally invasive neurosurgical imaging) systems for endoscopic and navigation-assisted microsurgery, the OME 7000 and OME 8000 series. These scopes provide multi-image monitoring with an in-field monitor that can be positioned in seven different directions, the company says. The systems also feature a built-in, larger monitor for display of information from a navigation system, MRI, CT or endoscopic image.
• The Leica MS2 combines ultra-high flexibility with an innovative stand, including automatic balancing of the swingarm, electromagnetic brakes, and a specialized balancing system. This scope offers xenon illumination, motorized zoom and focus, selection of different binocular and co-observation tubes, easy-to-read control unit LCD display, built-in auto diagnostic system and laser adaptability.
• M'ller offers the 20-1000 with high-resolution, apochromatic optics and improved depth perception. M'ller says the depth of field can be increased with a switchable diaphragm. The scope's floor stand provides xenon illumination, with back-up xenon light. Its special "senso-drive" enables smooth and precise movements.

Multi-specialty

• M'ller offers the Universa 300 for ENT, dental, spine and reconstructive surgery. The Universa 300 offers variable inclination, an inclinable eyepiece with wide angle oculars, motorized focus, ergonomic handles, long and short stereoscopic observer, and a video camera adapter.

What matters to the surgeon
Optics (resolution, illumination, depth of field) is the most important feature of the scope. Optical needs differ among specialties, a point if you are buying a scope for cross-purposes. In ENT, resolution or clarity may be more important than illumination. In ophthalmology, coaxial illumination is very important - the light has to show the delicate clear optical structures but not be so strong as to damage the retina.

Other important features include:

• The foot pedal. Make sure it will fit where the surgeon likes to place it and get a sealed foot pedal so it resists damage from surgical fluids.
• Pupillary distance. Is it narrow or wide enough to fit all the surgeons who will use it?
• The oculars. Can they incline to the degree your surgeons need? Also, you can extend the life of an older scope by adding new, larger oculars. They can be pricey ($6,000 to $7,000), but they cost less than buying a new scope.
• Eye relief. This is distance from the eyepiece to the surgeon's eye. If you don't have enough eye relief (1 to 1.5 inches) surgeons who wear glasses won't be able to wear their glasses to perform surgery. Although some surgeons can dial their eyeglass prescription into the scope, others can't. The scope won't correct astigmatism or significant hyperopia or myopia.
• Working distance. This is the distance from bottom lens of scope to the patient, and it varies from specialty to specialty. For multi-specialty use, look for a scope that offers a wide range of working distances that can be easily adjusted.