A deft hand and a bright light are two of the key components of vitreoretinal surgery. The development of an instrument that maximizes both makes bimanual vitreous surgery possible. Topcon's OMS-800 operating microscope Optical Fiber Free Intravitreal Surgery System
(OFFISS) component eliminates the need for hand-held fiber-optic illumination, which means the surgeon can use both hands for manipulating surgical instruments during
vitrectomies. According to Ricardo Amiron, product manager, Topcon, this is a first in intravitreal surgery. "The surgeon is free to simultaneously use two instruments such as scissors and forceps, intraocular probes and forceps or two forceps," he said.
OFFISS affords illumination over the entire operative field, including the peripheral area. According to internationally-based retinal surgeons who have incorporated this equipment into their practices, this feature results in more efficient and safer procedures. Even in patients with small pupils, surgeons have a clear stereoscopic view because of a built-in stereo
Three types of illuminations are available with the OMS-800: retro illumination, three-angle illumination (combining retro and inclined illumination), and yellow filter to protect the retina against
phototoxicity. With the yellow filter, a surgeon can operate for 111 minutes without inducing
phototoxicity. This claim is based on the difference between the amount of radiation produced by the OMS-800 with OFFISS and the threshold for retinal damage due to
phototoxicity. The retinal irradiation with OFFISS is 30mW per square centimeter. The threshold for retinal damage is 200 Joules per square cm.
Amiron, built-in slit illumination facilitates fundus observation with high contrast and less flare than conventional operating microscopes. "What's more," says
Amiron, "OFFISS provides exceptional working distance between the 40D non-contact lens and the patient's eye."
The concept of bimanual surgery is not foreign in ophthalmic surgery, but it is relatively new to the retinal field. A Japanese study of the bimanual vitreal surgery technique using the OMS-800 with OFFISS resulted in confirmation of the system's efficacy. Masyayuki
Horiguchi, MD, Yoshihisa Kojima, MD, and Yoshiaki Shimada, MD, of the department of Ophthalmology at Fujita Health University School of Medicine in
Toyoake, Japan, performed bimanual vitrectomy in 37 eyes with preretinal membranes due to diabetic retinopathy or
proliferative vitreoretinopathy.1 The surgeons reported that the membrane dissection and hemostasis were performed without incident, and an improvement in visual acuity of two or more lines was achieved in 30 of the 37 eyes. Five eyes resulted in no changes in two or more lines and two eyes had a decrease in visual acuity of more than two lines. There was no evidence of phototoxicity in any of the cases.
A recent development in the system's evolution is the addition of a multicoated contact lens. The new lens is made of quartz, and its multicoated surface has properties that decrease light reflection and increase light absorption, according to
This reusable lens is placed on the cornea, and the coaxial light from the operating microscope alone enables surgeons to obtain a clear image of the retinal surface. This new vitrectomy contact lens is particularly useful in the bimanual surgical treatment of eyes with proliferative membranes according to its creators, Kazuaki
Kadonosono, MD, Kazuro Yabuki, MD, Tadayuki Nishide, MD, Eiichi Nomura, MD, Eiichi
Uchio, MD, and Tadashi Yamakawa, MD2
Kadonosono, Yabuki, Nishide, Nomura, and Uchio are from Yokohama City University Medical Center's department of ophthalmology, and Dr. Yamakawa is from that facility's department of endocrinology and diabetes. The contact lens is not yet available in the United States. They have no financial interest in the contact lens.
Horiguchi, M et al. New System for fiberoptic-free bimanual vitreous surgery. Arch Ophthalmol. 2002; 120:491-494.
2. Kadonosono K, et al. Multicoated contact lens for bimanual vitreous surgery without
endoillumination. Arch Ophthalmol. 2004;122:367-368.