Giant retinal tear induced retinal detachment

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Retina

All India Institute of Medical Sciences, New Delhi

J ules Gonin changed the entire concept of pathogenesis of retinal detachment and identified retinal breaks as the cause of retinal detachments1. He developed the surgical technique of drainage of subretinal fluid beneath the retinal break combined with direct treatment of the break by transscleral cautery (ignipuncture) with a success rate of 40%2. The invention of binocular indirect ophthalmoscope made the localisation of the breaks easy. Custodis in 1949 described non drainage sclera buckling with polyvinyl explants with a success rate of 80%. Charles Schepens in 1951 described a technique of sclera buckling with the help of intrascleral silicone implant with diathermy with a success rate of 80%. In 1964 Harvey Lincoff used cryopexy along with silicone sponges for treatment of retinal detachment with a success rate of about 80%.

Scleral buckles changes the geometry and physiology of the eye. It changes the direction of the vector forces so that it overcomes the forces tending to detach the retina. The principle of buckling surgery is “to seal all the breaks”. Different methods are used to create these chorioretinal adhesions like diathermy, cryopexy or laser photocoagulation.

The advantages of sclera buckling over PPV in RRD are many as enumerated below:

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Retina
•	Excellent attachment rates of 90% in well selected	At last we come to the question, where does conventional surgery stand up against the ever evolving modern day vitreous surgery with vitrectomy machines having better fluidics causing less retinal flutter, better endoilluminators, bent probe lasers and good microscopes. Possibility exists that the next generation of vitreoretinal surgeons, weaned on the sutureless incisions, will be slower to acquire the necessary skills in external buckling anyway. So should we assume that are we seeing the end of buckling procedures? or does it still have to offer something which PPV can’t? The answer is YES! As we have discussed earlier the vitrectomy is not without complications and it also has as slow learning curve for the beginners. It is very difficult to achieve a complete vitrectomy in a young phakic patient which can predispose to PVR formation leading to redetachments. Increased IOP, cataract formation in phakic patients and silicone oil induced corneal de-compensation or band shaped keratopathy are the major complications after vitrectomy. The patients also require a second surgery for silicone oil removal. Thus scleral buckling surgery still has role in this modern era of vitrectomy surgeries in selected cases.

•	Essentially extra-ocular, non invasive intra-ocularly

•	No intraoperative complication such as iatrogenic
breaks, lens touch and port site dialysis.
•	It does not have oil related complications such as
cataract and glaucoma.
•	It is a single procedure as there is no requirement of oil

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In 1980 Kloti broadened the indications of PPV and coined the term “primary vitrectomy in RRD”6. Next three decades saw an immense improvement in instrumentations, vitrectomy machines, operating microscope, intensified endoilluminators, endolasers and wide angle viewing system which further led to the expansion of PPV to all kinds of RRD. The advantages of PPV over sclera buckling in RRD are many as enumerated below:
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•	It is less likely to cause refractive error which was very

•	There is no risk of retinal haemorrhages and retinal

•	Primary PPV - very useful in cases where retinal breaks
could not be identified preoperatively which is an essential prerequisite for sclera buckling.
•	Minimal invasive vitrectomy surgeries help in easy
recovery with less pain and more comfort.
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In addition to all the above mentioned advantages of pars plana vitrectomy it also has some complications inherent to the procedure and to the tamponading agent (silicone oil)