New 3-D monitor brings surgery into digital world

By Stefanie Petrou-Binder MD

NUERNBERG — Why stare into a microscope eyepiece when you can perform surgery viewed on a large freestanding 3-D screen?
That is a question answered by Heinrich Gerding MD, best poster prize winner at this year’s Congress of the German Ophthalmic Surgeons.

“An updated viewing system should accompany the advancement of optical surgical devices and machinery. Ophthalmology is developing in line with other surgical fields which have discovered that a 3-D monitor affords the surgeon an ergonomical and modern workplace,” Dr Gerding.
The system, developed by German company SeeReal GmbH, uses a stereoscopic viewing system to produce 3-D intraocular images. A computer program digitally slices the images into parallel segments and renders a stereoscopic composite image.

The monitor is not only freestanding with a horizontal pitch of 40°, but offers an enlarged representation of the visual field. Surgeons see “augmented reality” images of the ocular surface, anterior chamber and vitreous space. The eye anatomy seems somewhat larger and has a plastic effect.
In Muenster, ophthalmic surgeons used this system in a number of successful intraocular operations. Preliminary surgeries included both anterior and posterior segment procedures, which all involved the substitution of the microscope with the 3-D monitor system.

Dr Gerding performed vitrectomies, scleral procedures, conjunctival and anterior chamber rinsing, keratoprothesis, repeat keratoplastic surgery, IOL exchanges, anterior epinuclear removal, posterior lens removal and pucker peeling.
He operated on eight patients implementing this new system. The cases included one 20-year-old trauma patient as well as seven older patients ranging from 51 to 83 years.
The surgical outcomes were favourable, with all patients showing complete retinal reattachment and improved visual acuity after surgery. The surgeons were able to perform all operations safely.

The stereoscopic monitor was easy to use and provided a successful and comfortable replacement for the microscope. In fact, with the use of weak intraocular illumination, Dr Gerding reported that the system allowed the surgeon an extended viewing capacity beyond normal physiological limits.
The system’s workplace comprises a Zeiss OPMI CS microscope with ray diffracters and video adapters (Zeiss F 85). It has a 3.5 Zoll sensor and 725 x 582 pixel display, capturing 25 pictures/second.

The device has two 3CCD digital video cameras (Zeiss ZEP 925) and a Dresden 3-D picture system with a D4D-stereo 46.0 cm true colour screen with TFT 18.1 Zoll and 1280 x 1024 pixel resolution. The tracking system includes two infrared cameras, a 50° scan field and a stereo film recorder.

Previous attempts at devising 3-D viewing systems failed because of certain technical or practical disadvantages. Three-dimensional representation, attempted by using red/green image colour-coding and red/green glasses; by using polarisation filters; or by introducing mini monitors, offered similar pseudo-realistic representations but proved impractical for regular clinical adaptation.
The drawbacks among other things included the bulky head monitor systems, shutter glasses and polarisation effects.

The Dresden 3-D monitor has none of these drawbacks and offers the surgeon new possibilities. The system is designed to be able to replace surgical microscopes, offering advantages in the size and detail of the intraocular picture.
Recording, archiving and immediate playback options of the 3-D images offer further surgical scope. Recorded surgeries are invaluable to post-procedure training for both students and interns, he noted.

Dresden 3-D has been used as an additional viewing system for surgeons performing microsurgery in anterior and posterior segment surgeries. It has also been added to 3-D slit-lamp microscopy and 3-D video recording.
The 3-D monitor has already proven useful in teaching hospitals and for practicing interns in surgical specialties for both endoscopy and microscopy.
Dr Gerding said the system reflects the latest ideal of a modern and well-equipped operative workplace by providing surgeon comfort and a precise monitoring system.

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