Leica M844

Leica M844 – model overview

The Leica M844 is an ophthalmic microscope intended for procedures on the anterior and posterior segments of the eye. It belongs to the Leica microscope portfolio and combines the QuadZoom optical system with the independent OttoFlex II illumination module. QuadZoom uses four separate beam paths to provide a stereoscopic image for the surgeon and assistant. OttoFlex II helps produce a clear red reflex and reduces stray light passing through the sclera.

The microscope head has a motorized 6:1 zoom and motorized focusing with a range of 54 mm. The XY module, with a travel range of 58 × 58 mm, allows precise movement of the optical axis relative to the surgical field, while the head tilt mechanism, with a range from +15° to −50°, allows the head position to be adapted to the procedure. These features allow the optical axis to be repositioned without moving the entire stand.

When choosing a specific unit, the optical configuration, suspension system and other equipment need to be taken into account. Differences may include the assistant view, controls and video system components.

Leica M844 applications in ophthalmology

The Leica M844 is an ophthalmic surgical microscope for advanced anterior and posterior segment surgery.

OttoFlex II and the red reflex

The Leica M844 uses direct halogen illumination and an independent OttoFlex II module. The main illumination lights the surgical field, while OttoFlex II helps produce the red reflex. The two separate systems can be adjusted independently to suit the conditions of the procedure.

OttoFlex II reduces stray light passing through the sclera and increases red reflex contrast. The illumination field diameter is adjustable from 4 to 35 mm at a working distance of 200 mm. This supports observation in more demanding conditions, including a small pupil or advanced cataract.

The main light source uses two 12 V / 50 W halogen lamps in a quick-change lamp mount. The system includes filters that block IR and UV radiation.

Posterior segment surgery

The Leica M844 can be used for vitreoretinal procedures, including vitrectomy. The microscope can work with wide-angle observation systems for the posterior segment and image inverters. The system can be expanded with equipment such as the Leica RUV800 with a built-in inverter or Oculus SDI/BIOM solutions, selected to suit the procedures performed and the working setup.

VR mode allows a separate set of settings to be prepared for posterior segment surgery. In a suitable configuration, selected functions can be assigned to the foot control to coordinate the XY module, illumination and image inverter, among other functions.

Key technical specifications of the Leica M844

QuadZoom and optical parameters

The QuadZoom system uses four separate beam paths to provide a stereoscopic image for the surgeon and assistant. A shared motorized 6:1 zoom synchronizes magnification in the surgeon’s and assistant’s views. The system provides the same amount of light and the same image magnification at both positions. In a suitable configuration, the assistant bridge can be quickly moved from the left to the right side, while independent focus adjustment allows the image to be adapted to the assistant’s needs.

The optical system uses apochromatic correction and Leica OptiChrome objectives. The magnification range specified for a configuration with an f = 200 mm objective (WD 175 mm) and 10× eyepieces is 3.5×–21×.

The Leica M844 can be equipped with a fixed focal length objective with f = 200 mm (WD 175 mm), f = 225 mm (WD 200 mm) or f = 250 mm (WD 225 mm). The WD 175 mm version provides slightly higher base magnification and a shorter working distance, so it is sometimes chosen for precise anterior segment procedures. The WD 200 mm objective is a versatile option for cataract and corneal surgery, while providing sufficient space for instruments. The WD 225 mm version further increases the working space above the patient’s eye. Motorized focusing with a range of 54 mm allows focus adjustment, while the 58 × 58 mm XY module moves the optical axis without repositioning the suspension system.

Controls and function automation

The controls can be adapted to the microscope configuration and the operator’s preferences. A programmable foot control provides access to selected functions, while user settings allow individual operating parameters to be saved. StepCycle organizes operation into programmed sequences, while Auto Reset supports a prompt return to predefined settings after the microscope has been repositioned. The range of supported functions, including zoom, focusing, the XY module and illumination, depends on the configuration of the system.

Leica M844 suspension system

The Leica M844 microscopes offered by Medical Elektro are configured with the Leica F40 mobile stand. The suspension system provides stable support for the head and precise positioning of the microscope over the surgical field. Details of the stand design, electromagnetic brakes and ranges of movement are described on the Leica F40 page.

Leica M844 compared with the M820 and M822

The Leica M844 and Leica M820 share some design features but remain separate models. The main difference is the optical system: the M844 uses QuadZoom with four separate beam paths, while the M820 has two beam paths.

The Leica M822 is the successor to the M820 and uses different illumination solutions. It combines LED main illumination with the halogen coaxial OttoFlex system that produces the red reflex. This is one of the significant differences from the M844, which uses halogen main illumination and an independent OttoFlex II module.

What determines the price of a used Leica M844 microscope?

On the used equipment market, the price of a Leica M844 microscope depends on its technical condition, completeness and individual configuration, including the suspension system, assistant observation path, objective, controls and equipment for wide-angle observation or image recording. At Medical Elektro, the level of preparation is neither an offer option nor a factor that differentiates pricing, because every unit offered is refurbished to the same standard. The price is determined individually for the complete configuration.

Refurbished Leica M844 microscopes at Medical Elektro

The term “used” means that the microscope has previously been in service. A refurbished surgical microscope is a used device that has undergone a multi-stage process of preparation for sale.

Refurbishment at Medical Elektro follows a single standard that applies to the complete configuration of each unit. For the Leica M844, this covers the complete microscope with its corresponding suspension system and the actual optical, observation, illumination and control equipment of that unit. Each refurbished unit is presented with its own photographs and a description matching its configuration, and is covered by a 12-month warranty. The detailed scope is described on the surgical microscope refurbishment process page.

Leica M844 microscope availability

The list of Leica M844 units is updated automatically. Availability, configuration and equipment information is provided for each unit.

Contact Medical Elektro for assistance with selecting a Leica M844 microscope, information on the equipment of available units and an individual quotation.