OPHTHALMIC MICROENDOSCOPE

(OME) IN OPHTHALMOLOGY

Emin ÖZMERT, M.D.

Ankara University Faculty of Medicine

Vehbi Koç Eye Hospital - TÜRKİYE

ESASO / ANKARA – Sept 2012

OME IN VITREORETINAL SURGERY

Vitreoretinal surgery techniques and

instrumentations showed important developments recently

such as:

► İris retractor

► Wide – angle imaging systems

► Second illumination systems (Chandelier, Eckardt )

► Illuminated instruments ( forceps, endolaser, cannula )

► New operating microscopes

Despite these developments, sometimes we need

another assistant during VRS --------- OME

ENDOSCOPE IN VITREORETINAL

SURGERY

Endoscope serves not only for diagnostic

purposes, but also aids in vitreoretinal surgery

as a surgical tool

WHY ENDOSCOPE ?

Microscopic imaging becomes

limited or impossible due to:

► Small / fixed pupil, sudden miosis

► Intraoperative unexpected ocular

media opacifications

► Intraoperative cataract formation, capsular haze

► Light reflections occuring during

fluid / air exchange

The OME allows a clear view and to

continue the surgery when these

anterior segment conditions

preclude a posterior view

Traumatic corneal opacity, undergone VRS,

diagnostic endoscopy

WHY ENDOSCOPE ?

The major causes of surgical failure in VRS

cases are:

► Development of anterior PVR and

cyclitic membrane

► Inadequate laser application on the

peripheral retina

► Tissue / retina incarceration into the

sclerotomies

► Placement of infusion cannula into the

subretinal space

Visualization of inaccessible region of

the eye

An excellent microscope view may be

achieved using WAOS, but it is very

limitid or restricted in the outermost

periphery. The OME can easily image

and assist laser delivery to the retroiridal

region

PDR, endoscopic viewing of far

peripheral retina and laser application

WHY ENDOSCOPE ?

► New imaging techniques such as intraoperative endoscopic fluorescein angiography

► Glaucoma Surgery:

* Iridocorneal angle surgery

(goniotomy, lase iridoplasti,

synechiotomy) in cases with dense

corneal opacity

* To evaluate ciliary processes

condition before performing ECP

under direct viewing

* To reopen ab interno occluded

filtering bleb

WHY ENDOSCOPE ?

► Lacrimal Surgery:

* Direct and dynamic

visualization of the

lacrimal drain way; removal of

stenosis using special laser

*Complete outpatient DCR

surgery with the introduction of

new lasers ( STAR 980 )

OPTOSGROUP

SCHWIND ENDOGNOST

THE TYPES OF OPHTHALMIC

MICROENDOSCOPES

► Gradient index ( GRIN ) solid- rod

► Fiberoptic bundle ( pixel )

They share the same basic characteristics

* Endoscope probe: imaging, illumination, laser fibers

- Intraocular portion: Objective GRIN lens on the tip

- Handpiece

* Lenses for magnification, focus

* CCD video camera: 1 – 3 chips, electronic control unit

* Light source: Xenon lamp, UV / IR flters

* Laser source: Argon, 810 nm diode, STAR 980

* Video monitor: High resolution

* Image capture devices: videocassette recorder, video printer, computer

* Relevant equipments: Gloucoma, lacrimal surgery; FA

OPHTHALMIC MICROENDOSCOPES

FIBEROPTIC MICROENDOSCOPE

► Objective GRIN lens on the

distal tip of the image guide

► Tightly packed quartz fiber

bundles ( 3000 – 10.000 )

► CCD camera, focusing lens

and orientation ring remote

from the handpiece

► 50 – 70, 110 degree field of

view

► Depth of field: 0.75 – 40 mm

FIBEROPTIC MICROENDOSCOPE

► Fused – fiber endoscopic

system

► 19 / 20 G handpiece

containing:

* laser fiber in working

channel

* illumination fibers

* viewing fibers

FIBEROPTIC ENDOSCOPE

Advantages:

► Lighter handpiece: The

surgeon does not hold

the video camera in hand

► Far less bulky and

cumbersome

► It gives a brighter image

► Semidisposable

FIBEROPTIC ENDOSCOPE

Disadvantages:

► Resolution is limited by the

density of the glass microfibers

( pixelization, honeycomb

effect on monitor )

► Because the depth of field is

less than the GRIN

endoscope, the object

becomes blurred when the tip

gets to within 2 mm of the

object

GRIN MICROENDOSCOPE

► Objective GRIN lens on the

distal end of glass rod

► Long slender GRIN solid rod

lens

► Handpiece (endoscopic body)

contains magnifying and

focusing lenses

► Surgeon hold the videocamera

in hand

► Foot pedal control of

magnification

GRIN ENDOSCOPE

Advantages:

► Extremely high resolution

without pixelization of the

image ( no honeycombing

effect )

► Able to focus in close working

distance, usually less than 2

mm

* Subretinal space

* Lacrimal system

► High magnification view of ILM

or other membranes not seen

through the usual operating

microscope

► Magnification increases as

distance to object decreases

GRIN ENDOSCOPE

GRIN ENDOSCOPE

Disadvantages:

► Cumbersome and bulky: It does

get heavy during a long case

( surgeon hold the videocamera

in hand )

► Fragility, additional expenses

► It does suffer from greater light

loss in the lenses

ENDOSCOPES IN MARKET

OPTOS

GROUP SCHWIND OTI INSIGHT

ENDO

OPTICS

OUTER

DIAMETER ( mm )

0.75 – 1.0 0.9 – 1.0 0.9 19 – 20 G 20 G

IMAGE GUIDE

SYSTEM

10.000 pixels

6000 pixels 10.000 – 30.000 pixels

GRIN GRIN

FIELD OF

VIEW ( degree )

75 - 90 70 - 120 74 50 - 110GRIN

LACRIMAL

SURGERY+ + - - -

OTHER

FEATURES

►Foot pedal control of illumination

►STAR 980►Several

modules

►Er:YAG dacryostom

►Optics for Schlemm

►Several modules

Several modules ►Foot pedal

control of magnification

Integrated in

a case

IE – 3000 INSIGHT INSTRUMENTS

GENERAL DISADVANTAGES OF OME

► Complexity of setup, postoperative maintenance, cost, fragility

► Technical adaptation and learning curve are mandatory.

The surgeon learn rather quickly to use the video monitor

and to overcome the lack of stereopsis

► Extensive bimanual membrane dissection is impossible

► There is no stereopsis. With a 110° wide – field

endoscope, the surgeon can gain orientation within the

vitreous cavity

CONCLUSIONS

The technique of OME in

ophthalmic surgery

► Expands and extends visual control

during VRS when standard

microscopic viewing is limited or

obscured,

► Often provides restoration of

visualization in order to continue or

complete necessary surgical

maneuvers