Wide angle viewing system
- 1. An Indispensible Tool In Vitreoretinal Surgery DR. ABHIJAAT CHATURVEDI DR. SAURABH LUTHRA DR. S.M. DAS DR. SHWETA PARAKH DR. VAIBHAV BHATT
- 2. Good microscope Vitrectomy setup-illumination, cutter, AFE/Si oil capability, compatibility with 23 and 25 gz system Endolaser with LIO Good VR instruments Dyes WAVS
- 3. Conventional viewing systems Wide Angle viewing Systems Infusion contact lens (Hand-held irrigating lens) Contact type Hands-free contact lens (Landers) VPFS (Vitreous Panfundoscope) Suture-less Lens system CWF (Contact Wide field system) AVIS (Advanced Visual Instrument system) ROLS (Re-inverting Operating Lens System):- Clarivit, HRX (Volk). Non-contact type BIOM –Oculus (Binocular Indirect Ophthalmoscope) MERLIN – Volk EIBOS – Erect Indirect Binocular ophthalmoscope OFFISS – Topcon (Optical Fibre Free Intravitreal Surgery System) RESIGHT – Carl Zeiss Peyman-Wessels-Landers ARTEVO 800 – Integrated Digital Microscope (Carl Zeiss)
- 5. Neutralizes high convergance of corneal curvature to focus on Vitreous and Retina. 3 types of lenses – ◦ Plano-concave lens – view of 20 deg. ◦ Bi-concave lens – view 30 deg. ◦ Prism lens – meridional view of 60 deg.
- 6. Sew-on Lenses (Lander’s Lens)-C.L is put over a stainless steel ring which is sewed at the limbus with the sclera. Bubble or blood can enter. No assistant help required.
- 7. Plano-concave lens – Core vitrectomy. Bi-concave lens – visualization in air-filled eye. – 90D lens – 25 deg angle field. Machemers magnifying lens – surface details on posterior pole.- 30 deg angle field. Peyman wide field lens – equatorial portion. Tolentino 20 deg prism – Retinal periphery. Tolentino 30 deg prism – Extreme periphery.
- 8. Spitznas(1984)-Rodenstoeck panfundoscopic lens with stereotactic manipulator- stereoscopic diagonal inverter(SDI) 1987- BIOM system (Binocular indirect ophthalmomicroscope) Spitznas M,motorized teleguided stereotactic manipulator for VR Surgery.Arch ophthal 1983;101:623-30. Spitznas M.SDI for wide angle vitreous surgery Graefes Arch clin exp ophthal 1987;225:9-12
- 9. High convex lenses(60-160 D) Real, inverted, minimally magnified with a reinverting system(SDI) Final image appears that seen with planoconcave lens Magnification-0.4 to1.1x Field of view-90-130 degrees Better stereopsis
- 10. Ease of surgery Overall picture of pathology Greater depth Easy view in gas fluid exchange Si oil-PFCL exchange Bimanual surgery
- 11. Contact Non contact Advantages Better Image resolution & stereopsis. No Intra-op corneal trauma. Eliminates corneal abrasion and limits the number of reflecting surfaces. Good view during fluid-air exchange. Wider field of view (150 deg) – less need of Ocular rotation. Good view – small pupils and irregular corneas. Disadvantages Requires skilled assistant / sewn on lens. Poorer image resolution & depth perception. Poor view in case of corneal or lenticular opacity/haze. More learning curve. Chances of corneal deformation. Does not neutralize corneal astigmatism. Image is lost if eye is moved. Fogging of lens. Blood/air bubbles mar the view. Expensive.
- 12. Indirect ophthalmoscopy system-fundus image. Stereo-re-inverter prism system-reinversion of the image.
- 13. First Component:- (inferior lens) • Planoconcave lens (+13D) neutralizes the refractive power of cornea and makes the patient highly myopic. • Image is formed b/w the retina and crystalline lens.
- 15. Second Component (Superior lens):- • Convex lens (+150D), 0.5 mm anterior to contact lens element, converges these rays • Forms a real and inverted, aerial image anterior to the image forming lens system.
- 17. Posterior surface of lens becomes strongly refractive. (64 D). Refractive power of eye- (59 D to 102 D). Field of view – 130 deg. Microscope eye piece should be moved closer to patient’s eyes.
- 18. 3 Models ◦ 1-closed cone device ◦ 2-open arm device ◦ 3-foot controlled motorized focussing Condensing lens (130 deg) and objective lens with SDI. SDI is nonsterile. Intermittent corneal wetting. Flip up design permits removal from visual axis. Sterlized with ETO or autoclaved.
- 19. Microscope light is turned off. BIOM knob- ◦ 1 -1.5 inch below highest setting. ◦ Counterclockwise-elevates objective lens-focus down. ◦ Clockwise-lowers the objective lens-focuses upwards. Focus the disc with endo-illumination and low level of magnification. Periphery-tilt the eye in XY axis or increase the bottle height.
- 20. 132 D - Upright vitrectomy lens. Wide field upright images without inverter. (internalized prisms). Operating table mounted system, can be attached to any microscope.
- 21. Optical Fibre Free Intravitreal Surgery system, is a wide-angle viewing system with incorporated light illumination, no need of light probe.
- 22. Advantages- Surgeons can see fundus with illumination incorporated into the microscope without using a light probe. Therefore, it allows surgeons to perform bimanual technique with regular instruments. The surgeon can adjust the focus using the foot pedal of the microscope. Disadvantage- It cannot be adapted to other microscopes. This implies buying the whole system (including the microscope), thereby increasing the cost.
- 23. Incorporated inverter and indirect system in one piece. Inverter cannot be used independently. Incorporates spring balance safety elevation of the unit – if lens comes in contact with the eye. Field of view – 100 – 125 deg. 90, 132 D lenses.
- 24. Can hold two lenses simultaneously. 128 D lens – Wide angle field. 60 D lens – High resolution Posterior pole image. Equipped with an inner focusing system that allows the reduction lens set inside the microscope to be moved automatically.
- 25. Modified Rodenstock panfundoscope. Field of view – 130- 150 deg. Inverted image – SDI needed. Easy introduction of instruments without disturbing the lens.
- 26. Inverted image – SDI needed. Field of view 120 – 130 deg. Held by handle or standard lens ring. Lighter than VPFL.
- 27. AVI stereo inverter. Has 2 miniature lenses, Field of view – 68 deg & 130 deg. Hand held by assistant or self retaining ring type. Smaller, lighter, allows easy manipulation of lens. Allows visualization in small pupil or air-filled eyes.
- 28. Single element reinverting prism. Designed to correct the inverted image. MiniQuad -156 D, 0.39× MiniQuad XL - 156 D, 0.39× ClariVit wide angle - 156 D, 0.39×. Panora View - 128 D, 0.47×.
- 29. Completely integrated digital microscope for heads-up surgery. 25% higher resolution and light transmission – outstanding depth of field. Integrated intra-operative OCT. Quick switch between anterior and posterior segment modes. Anterior segment mode – phacoemulsification sx (Toric IOL position markers).
- 31. BIOM 19 132 102.9 RESIGHT 17 128 94.9 OFFISS 21 120 130.2 MERLIN 14 140 88.9 Landers 18 132 99.9 EIBOS 20 132 105.8 RUV800 20 132 105.8