We’ll start this off by making a claim that Haag-Streit makes the highest quality slit lamps on planet Earth. Now that we have that out of the way– let’s indulge on this rare moment where an instrument comes to our facility and we have few negative things to say about it- that isn’t to say we don’t have one or two things worth addressing later on. This is the slit lamp that has made young people decide to become ophthalmologists. Even Haag-Streit themselves claim that some guy named Georg Eisner decided to become an OMD based solely on an experience he had looking through a BM900 slit lamp. Quite the statement though- nonetheless, probably true considering that Haag-Streit slit lamps have been the benchmark for microscopic diagnostic evaluation for nearly 50 years- renowned in every corner of the world and endorsed by over 200 global ophthalmic societies. The company further claims that over 110,000 eye care professionals have purchased a Haag-Streit slit lamp; 4.6 times the number of Ophthalmologists in the USA alone. So what is it about a Haag that makes it so special? We could get into the nitty gritty mechanics of the BM900 but to save you several hours we’ll just mention the highlights that’ll convince you of becoming a Haag parent. Firstly, the BM900 has a stunningly clear optical path, starting with oculars that seem to reduce fatigue that others slit lamps seem to cause. This is aided by an illumination source that is incredibly bright and crisp even with halogen illumination and a well-lit room. Maneuvering the BM900 is something of a well-handling luxury sports-sedan that effortlessly glides along the base and elevates with a gentle turn of the wrist and every other mechanical movement via knob, switch, or button has been very well thought-out. Naturally though, this wouldn’t be a proper Buzz review without some insight into the things we question and the things we doubt. For instance, it would be nice of Haag-Streit to update the material and design ever-so slightly. The BM900 hasn’t changed much at all in the last 20 years, and even the materials used to produce the new units are still quite heavy and crude. But then again, if you’re the best selling slit lamp in the world, why change it?
OUR TAKE: Two-handed elevation keep this from being our favorite (see BM-900).
The BM 900 has been the standard in modern slit lamp microscopy for more than 55 years – and still is! Over 100,000 professionals all over the world who own a BM 900 agree that it was the best investment they ever made for their practice. As with all Haag-Streit slit lamps, a Goldmann tonometer – the gold standard in IOP measurement – may be added to the system.
Equipped with a Kepler microscope, the BM 900 provides two standard magnifications: 10x and 16x. With a set of optional oculars it can be extended to 25x and 40x magnification. Like any other Haag-Streit slit lamp, the BM 900 features the best optical components to show all structures of the human eye in every detail.
Perfection in design, materials and construction allow these movements to be made smoothly and effortlessly without any wrist or finger strain and to continue doing so for the very long lifetime of this classic slit lamp.
Supplied with 10x eyepieces, the magnification switches from 10x to 16x through a control lever mounted on the micro- scope. 13 degree convergence, wide eyepieces and adjustable PD ensure strainfree viewing. The eyepieces are also adjustable for spectacle wearers.
Older Haag-Streit slit lamps are assembled with y-axis elevation functions on an additional knob in front of the joystick, instead of on the joystick itself. Two-hands are required in order to elevate and decline the slit lamp tower for patient examination. For the one-handed elevation instrument, see Haag Streit BM-900.
Any Haag-Streit slit lamp can employ a AT-900 or R-900 Goldmann tonometer with the use of a tonometer mount.
LED and Halogen illumination types are solely referencing the bulb type. Both still produce the same intensity of light however LED illuminations may appear slightly more stark than Halogen; the microscopes filter can counter act this. LED bulbs have a far longer life expectancy (despite a higher cost) than Halogens and typically burn ‘cooler’.
The Haag-Streit BM-900 series utilizes parallel optics to produce a 13 ̊ parallel binocular view.
In general, converging optics display a view produced from two oculars intersecting to produce the same image in each.
Parallel optics display a different image in each optic, operating in a mutually exclusive way.