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Indian Journal of Ophthalmology
Reply to comment on: Sandwich technique using combination of perfluoropropane and silicone oil for inferior retinal detachment Sir, We thank Mehrotra for putting forth the queries and showing interest in our article.[1] After fluid air exchange, to achieve an isovolumetric concentration of gas, the intraocular gas perfluoropropane (C3F8) was injected through the infusion port. This was followed by silicone oil injection through the superior port under direct visualization to fill up to half of the vitreous cavity.[2] The intraocular gas (C3F8) port was the last one to be removed in case further gas injection was needed. We understand the fact that the escape route for gas may be hindered while using silicone oil cannula on one side and endoilluminator on the other. However, escape of gas was allowed through the superior port itself by removing endoilluminator intermittently. The exit of gas while using valved cannula can be further challenging and risk of intraocular pressure rise remains. Though venting may be helpful for escape of gas in valved cannulas, the frequent removal of venting extension for reintroduction of endoilluminator can be cumbersome. We noted that anterior chamber was full of gas at the end of surgery in aphakic eyes. We did not identify any forward push of iris diaphragm or collapse of anterior chamber in our study eyes. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Comment on: Evaluation of retinal nerve fiber layer thickness after optic canal decompression Sir, We read with interest the article by Bhattacharjee et al.[1] The improvement in visual parameters of patients is interesting to observe. However, we would like to discuss a few points which might be of importance to readers. The two cases reported are essentially different in their time of presentation, 6 weeks in case 1 and 6 days in case 2. Hence, it may be presumed that case 1 supposedly must have had a more significant retinal nerve fiber layer (RNFL) damage as compared to case 2. The percentage change in RNFL after surgery in case 1 is not expected to be significant, although apparent changes may have been observed by the authors. However, because the authors have not mentioned raw data, the amount of improvement is unclear. In addition, because
Volume 66 Issue 11
Sumit Randhir Singh1,2, Deven Dhurandhar1,2, Jay Chhablani2 1 Academy for Eye Care Education, LV Prasad Eye Institute, Smt. Kanuri Santhamma Centre for Vitreo‑Retinal Diseases, LV Prasad Eye Institute, Hyderabad, Telangana, India
2
Correspondence to: Dr. Jay Chhablani, Smt. Kanuri Santhamma Centre for Vitreo‑Retinal Diseases, LV Prasad Eye Institute, Banjara Hills, Hyderabad ‑ 500 034, Telangana, India. E‑mail:
[email protected]
References
1. Mehrotra N. Comment on: Sandwich technique using a combination of perfluoropropane and silicone oil for inferior retinal detachment. Indian J Ophthalmol 2018;66:1657. 2. Singh SR, Dhurandhar D, Chhablani J. Sandwich technique using a combination of perfluoropropane and silicone oil for inferior retinal detachment. Indian J Ophthalmol 2018; 66:988‑90. This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution‑NonCommercial‑ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non‑commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms. Access this article online Quick Response Code:
Website: www.ijo.in DOI: 10.4103/ijo.IJO_1415_18 PMID: ***
Cite this article as: Singh SR, Dhurandhar D, Chhablani J. Reply to comment on: Sandwich technique using combination of perfluoropropane and silicone oil for inferior retinal detachment. Indian J Ophthalmol 2018;66:1658. © 2018 Indian Journal of Ophthalmology | Published by Wolters Kluwer - Medknow
maximum RNFL reduction happens at 6 weeks, it is highly improbable to obtain a significant thinning of the optic nerve after just 6 post trauma (case 2). Further, the signal strength of the left eye preoperative optical coherence tomographyin case 2 was 3/10, which rendered the data unreliable. Average RNFL thickness was seen to reduce from 90 µm to 84 µm, which is against the hypothesis suggested by the authors. After extensive literature search, we could not find any longitudinal study which has evaluated the change of RNFL after optic canal decompression. However, one long‑term study evaluating RNFL thickness after chiasmal decompression in 20 patients showed significant reduction in RNFL even at 3 months after surgery, with a 2.82% improvement at 6 months.[2] However, a net thinning was still observed from the baseline. Hence, we feel it is premature to comment on the effect of optic canal decompression on RNFL thickness based on these observations. Financial support and sponsorship Nil.
