Thomas Kuriakose1, Smitha Jasper1, Sherina Thomas2. 1. Department of Ophthalmology, Christian Medical College, Vellore, Tamil Nadu, India. 2. Fellow in Vitreoretinal Surgery, Narayana Netralaya, Rajaji Nagar, Bangalore, Karnataka, India.
Sir,We thank authors[1] for the interest shown in our article.[2] As the authors have pointed out, squeezing of the lids by the patients during topical anesthesia or inadequate blocks can be a cause of positive vitreous pressure. All our cases were done under peribulbar anesthesia and we had ensured that the blocks were adequate in all cases. It was not specifically mentioned in our article.Misdirection of infusion fluid causing raised vitreous pressure is only a conjuncture and it is difficult to try and prove it by ultrasound biomicroscopy (UBM) in a patient per-operatively. Though UBM can detect fluid just behind the lens only, the sensitivity and specificity of this test are not known. UBM is not useful for more posterior locations of the fluid. No UBM was done in any of our cases.As has been pointed out, there is a possibility that liquefied vitreous would have also been aspirated; the point we want to make here is that it is only aqueous/misdirected intraocular irrigation fluid or liquefied vitreous that can be aspirated through a 30-G needle and this will not cause vitreous traction and retinal tears. For the same reason, it is our belief that the complications of this procedure will be similar to intravitreal injection. Incorrect procedure can cause injury to the lens even with MIVS systems. We agree that, theoretically a 27-G MIVS system will be safer than the using of a 30-G needle through the pars plana to decompress the posterior segment. The question is how many anterior segment surgeons especially those in developing countries have such systems in their operation theater and if the cost is worth it when the procedure we described is available at next to no cost to achieve the same objective.