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Indian Journal of Ophthalmology Correspondence to: Prof. Ungsoo Samuel Kim, Department of Ophthalmology, Kim’s Eye Hospital, Konyang University College of Medicine, Youngdeungpo 4th 156, Youngdeungpo‑gu, Seoul 150‑034, Korea. E‑mail:
[email protected]
Vol. 64 No. 6
This is an open access article distributed under the terms of the Creative Commons Attribution‑NonCommercial‑ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non‑commercially, as long as the author is credited and the new creations are licensed under the identical terms. Access this article online Quick Response Code:
Reference
Website: www.ijo.in DOI: 10.4103/0301-4738.187685
1. Kim CH, Kim US. Large exotropia after retrobulbar anesthesia. Indian J Ophthalmol 2016;64:91-2.
PMID: *** Cite this article as: Kim CH, Kim US. Response to: Bilateral lateral rectus myotoxicity after retrobulbar anesthesia. Indian J Ophthalmol 2016;64:473-4.
Response to: Choroidal thickness changes after dynamic exercise as measured by spectral‑domain optical coherence tomography Sir, We appreciate the interest in and comments. [1] Some controversy accompanies the presence of autoregulative mechanisms in choroidal circulation. There are a lot of vasoactive substances both endogenous and exogenous that have been shown to affect the choroidal thickness (CT). We want to emphasize autonomic innervation, and autoregulation of choroid in particular, and we agree that the autoregulatory mechanisms of choroidal blood flow are extremely complex. However, the choroidal blood flow is thought to exhibit only a small amount of autoregulation compared to the retinal blood flow. Therefore, the CT is shown to be influenced by numerous extrinsic factors including blood glucose and blood concentrations of oxygen and CO2.[2,3] Thus, it is not surprising that hypothalamus is one of the main centers responsible for CT. On the other hand, the change in CT is thought to be obtained by redistribution of fluids or changes in the tonus of nonvascular smooth muscle.[4] Previous studies showed that choroidal blood flow changes in the contralateral eye when the ipsilateral eye was illuminated.[5] These results indicate that the response of choroidal blood flow is under neural control. Choroidal blood flow was found to decrease from light to dark adaptation whereas a decrease in retinal blood flow during illumination has been found in these studies. The author also mentions that lighting and light intensity of the room are important factors during optical coherence tomography (OCT) measurements, and it is very likely that they affect the test results. However, it may be necessary to ask how much light affect the CT measurements. However, we cannot answer this question, because when we searched the literature, we did not find any studies that evaluated the
CT during light and dark by means of OCT. Hence, in our study, all measurements were performed under the standard room lighting. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Nihat Sayin, Necip Kara1, Gokhan Pekel2, Hasan Altinkaynak3 Department of Ophthalmology, Kanuni Sultan Suleyman Education and Research Hospital, Istanbul, 1 Department of Ophthalmology, Gaziantep University, Gaziantep, 2Department of Ophthalmology, Pamukkale University, Denizli, 3 Department of Ophthalmology, Ataturk Training and Research Hospital, Ankara, Turkey Correspondence to: Dr. Nihat Sayin, Atakent Mahallesi, 4. Cadde, C 2‑7 Blok, Kat: 3 Daire: 13, Kücükcekmece, Istanbul, Turkey. E‑mail:
[email protected]
References 1. Sayin N, Kara N, Pekel G, Altinkaynak H. Choroidal thickness changes after dynamic exercise as measured by spectral‑domain optical coherence tomography. Indian J Ophthalmol 2015;63:445‑50. 2. Xu J, Xu L, Du KF, Shao L, Chen CX, Zhou JQ, et al. Subfoveal choroidal thickness in diabetes and diabetic retinopathy. Ophthalmology 2013;120:2023‑8. 3. Altinkaynak H, Kara N, Sayin N, Günes H, Avsar S, Yazici AT. Subfoveal choroidal thickness in patients with chronic heart failure analyzed by spectral‑domain optical coherence tomography. Curr Eye Res 2014;39:1123‑8. 4. Ulas F, Dogan Ü, Keles A, Ertilav M, Tekçe H, Celebi S. Evaluation
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Letters to the Editor June 2016 of choroidal and retinal thickness measurements using optical coherence tomography in non‑diabetic haemodialysis patients. Int Ophthalmol 2013;33:533‑9. 5. Fitzgerald ME, Gamlin PD, Zagvazdin Y, Reiner A. Central neural circuits for the light‑mediated reflexive control of choroidal blood flow in the pigeon eye: A laser Doppler study. Vis Neurosci 1996;13:655‑69.
This is an open access article distributed under the terms of the Creative Commons Attribution‑NonCommercial‑ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non‑commercially, as long as the author is credited and the new creations are licensed under the identical terms. Access this article online Quick Response Code:
Website: www.ijo.in DOI: 10.4103/0301-4738.187687 PMID: ***
Cite this article as: Sayin N, Kara N, Pekel G, Altinkaynak H. Response to: Choroidal thickness changes after dynamic exercise as measured by spectraldomain optical coherence tomography. Indian J Ophthalmol 2016;64:474-5.
Comment to: Effect of lanosterol on human nuclei Sir, We read with interest the recent study titled “Effect of lanosterol on human cataract nucleus” by Shanmugam et al.[1] The study was based on the novel research idea by Zhao et al.[2] which concluded that lanosterol reverses protein aggregation in the cataractous lenses of rabbits and dogs. In their study, Shanmugam et al. concluded that lanosterol has no role in reversing the cataractous changes on human nuclei. However, there are a few points; we would like to highlight. • Hejtmancik and Kantorow[3] have clearly described the different mechanisms of cataract formation in congenital and acquired cataracts in humans. Mutations in enzymes such as lanosterol synthase and mutations that destabilize the lens proteins lead to increased protein aggregation and cataract formation in congenital cataracts. In age‑related senile cataracts, a variety of biochemical and physical insults lead to changes in the lens proteins, increased protein aggregation, and cataract formation. Thus, studying the effect of lanosterol on the reversal of cataract would be more beneficial in cases with congenital or pediatric cataracts • In age‑related senile cataracts, the density of the nuclear cataract is directly proportional to the protein aggregation within the crystalline lens. Hence, the time duration for which the nuclei needs to be immersed in the lanosterol solution to achieve cataract reversal would be different for different nuclear density. In this study, all the nuclei were immersed in the lanosterol solution for 6 days irrespective of the density and type of cataract • Removing the lens epithelium and capsule leads to progression of the cataractous changes in the human lens. Thus, in this study, the progression of the cataract was noted in both the lanosterol group and control group. Different biochemical changes in the lens both in vivo and in vitro would have an effect on the outcomes. To conclude, factors such as immersion of the intact lenses with capsule, cases with similar nuclear density or increasing the time duration of immersion in the lanosterol solution, and studying the effect of lanosterol in patients with congenital or pediatric cataracts may result in positive outcomes.
Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Ramesh Venkatesh, Prachi Gurav, Shailja Tibrewal1 Departments of Retina-Vitreous, and 1Pediatric Ophthalmology, Dr. Shroff’s Charity Eye Hospital, Daryaganj, New Delhi, India Correspondence to: Dr. Ramesh Venkatesh, Dr. Shroff’s Charity Eye Hospital, 5027, Kedarnath Road, Daryaganj, New Delhi ‑ 110 002, India. E‑mail:
[email protected]
References 1. Shanmugam PM, Barigali A, Kadaskar J, Borgohain S, Mishra DK, Ramanjulu R, et al. Effect of lanosterol on human cataract nucleus. Indian J Ophthalmol 2015;63:888‑90. 2. Zhao L, Chen XJ, Zhu J, Xi YB, Yang X, Hu LD, et al. Lanosterol reverses protein aggregation in cataracts. Nature 2015;523:607‑11. 3. Hejtmancik JF, Kantorow M. Molecular genetics of age‑related cataract. Exp Eye Res 2004;79:3‑9. This is an open access article distributed under the terms of the Creative Commons Attribution‑NonCommercial‑ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non‑commercially, as long as the author is credited and the new creations are licensed under the identical terms.
Access this article online Quick Response Code:
Website: www.ijo.in DOI: 10.4103/0301-4738.187689 PMID: ***
Cite this article as: Venkatesh R, Gurav P, Tibrewal S. Comment to: Effect of lanosterol on human nuclei. Indian J Ophthalmol 2016;64:475.
