This work presents the technical aspects for the development of a firmware for a Nd:YAG laser based ophthalmic surgery microscope. The software design was developed for a Microchip® PIC18F4550 microcontroller. It interfaces the electronic blocks of the device and allows the calibration of the laser energy attenuator. The calibration data are stored into EEPROM’s for each Nd:YAG laser unit. The fast developing time of the software is achieved by using of Flowcode® 4 – a graphical programming tool for microcontrollers with customizable code software blocks. The software undertakes the specific requirements of a medical device.

Keywords: Laser surgical microscope, Ophthalmic microscope