Indian Journal of Ophthalmology

: 2002  |  Volume : 50  |  Issue : 4  |  Page : 356--357

Wide-angle vitreous surgery without stereoscopic diagonal inverter

A Kumar, G Prakash, Vijay B Wagh 

Correspondence Address:
A Kumar

How to cite this article:
Kumar A, Prakash G, Wagh VB. Wide-angle vitreous surgery without stereoscopic diagonal inverter.Indian J Ophthalmol 2002;50:356-357

How to cite this URL:
Kumar A, Prakash G, Wagh VB. Wide-angle vitreous surgery without stereoscopic diagonal inverter. Indian J Ophthalmol [serial online] 2002 [cited 2021 Apr 15 ];50:356-357
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Full Text

Wide-angle viewing systems (WAVS) for performing vitro-retinal surgery are increasingly popular because they provide a panoramic view of retina and vitreous. There is the distinct advantage of greater visibility following phakic air-fluid exchange. But WAVS relies on the stereoscopic diagonal image inverter (SDI).[1] We have been using WAVS (Volk, Inc. USA) for a couple of years now, and have found that WAVS can be used without SDI if the surgeon gains practice in performing the specific steps with an inverted image (as during indirect ophthalmoscopy).

The limitations that we encountered ranged from the high cost, increased height of microscope (41 to 45 mm, making it cubersome for surgeons of short stature to operate with ease), requirement of specific microscopes (specific models of Zeiss, Leica, Topcon etc that have been designated as being compatible with SDI) that increase the overall expense and also the deterioration of topical image quality due to insertion of a lens system. Moreover, the light intensity is also somewhat reduced due to distance from the retina. Once the SDI has been fixed to the microscope, the surgeon has to adjust to the height or remove-refit it frequently while performing anterior segment surgeries and other steps of vitrectomy surgery (that do not require WAVS). This is especially important where a variety of surgeries are performed using the same operating microscope by different surgeons on the same day (in an institutional setting). Added to this is the increased time, cost and manpower required for the proper maintenance of the inverter. Some newer models of SDI also use a separate power source.

Based on our observations, we trained ourselves to use 'WAVS without SDI'. The posterior segment surgeons being well-versed in the art of indirect ophthalmoscopy (inverted image) should not have a problem adjusting to this technique. The conditioned reflex of mentally inverting the retinal image (while using WAVS without SDI) would develop if the surgeon practices performing internal subretinal fluid drainage and endophotocoagulation in the initial few surgeries. A good assistant is usually required when using this technique. We would suggest that using 'WAVS without SDI' should be a familiar technique to the posterior segment surgeon and this can be mastered over 10-20 surgeries (personal experience).


1Spitznas M, Reiner J. A stereoscopic diagonal inverter (SDI) for wide-angle vitreous surgery. Graefes Arch Clin Exp Ophthalmol 1987;225:9-12.