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407
Letters to the Editor May 2016
Conflicts of interest There are no conflicts of interest.
clinical hypothesis based on the myotoxicity of local anesthetics. Arch Ophthalmol 1985;103:1337‑9.
Madhurima K Nayak Department of Ophthalmology, Kasturba Medical College, Mangalore, Karnataka, India Correspondence to: Dr. Madhurima K Nayak, C II 12, KMC Staff Quarters, Light House Hill Road, Mangalore ‑ 575 002, Karnataka, India. E‑mail:
[email protected]
References
5. Capó H, Roth E, Johnson T, Muñoz M, Siatkowski RM. Vertical strabismus after cataract surgery. Ophthalmology 1996;103:918‑21.
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1. Kim CH, Kim US. Large exotropia after retrobulbar anesthesia. Indian J Ophthalmol 2016;64:91‑2.
DOI: 10.4103/0301-4738.185633
2. Benoit PW, Belt WD. Destruction and regeneration of skeletal muscle after treatment with a local anaesthetic, bupivacaine (Marcaine). J Anat 1970;107(Pt 3):547‑56.
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3. Zink W, Graf BM. Local anesthetic myotoxicity. Reg Anesth Pain Med 2004;29:333‑40. 4. Rainin EA, Carlson BM. Postoperative diplopia and ptosis. A
Comment on: Choroidal thickness changes after dynamic exercise as measured by spectral‑domain optical coherence tomography Sir, We have read the article by Sayin et al. entitled as “Choroidal thickness (CT) changes after dynamic exercise as measured by spectral‑domain optical coherence tomography (OCT)”[1] with great interest. We would like to make some contributions that may broaden the discussion section on the factors influencing CT. A number of systemic, local, and ophthalmologic anatomical and physiopathological factors and environmental conditions may affect CT. [2] Contradictory results have been reported concerning the effects of the factors such as exercise and blood pressure on CT. [3] Choroid has a unique embryological development and neurovascular anatomy. [2] It has an intense network of sympathetic innervations. Furthermore, it has been shown that nerve growth factor regulates endothelial cell migration and proliferation during choroidal development. Choroidal microvessels are fenestrated although the fenestrae are not as frequent in choroidal capillaries as in the capillaries of other tissues. In addition, there are no desmin intermediate filaments in the choroidal pericytes, and there is a paucity of pericyte ensheathment.[2] The choroidal circulation is under autonomic neurogenic control.[2] Decreases in choroidal blood flow are mediated by activation of sympathetic, efferent nerves that release noradrenaline, activating alpha 1‑adrenoceptors on vascular smooth muscle cells. In turn, increases in choroidal blood flow are mediated by parasympathetic efferent nerves, which act via nitric oxide signaling. Moreover, human
Cite this article as: Nayak MK. Comment on: Bilateral lateral rectus myotoxicity after retrobulbar anesthesia. Indian J Ophthalmol 2016;64:406-7.
studies reported changes in choroidal blood flow not only in the light‑stimulated eye but also in the contralateral eye,[4] indicating that the response of choroidal blood flow is under neural control. Another important point is that hypothalamus is one of the centers responsible for autonomic nervous system (body temperature, systemic blood pressure, etc.), and it has complex interactions with other autonomic centers.[5] In the light of the aforementioned data, we suppose that the findings of this study may indicate that hypothalamus is one of the main centers responsible for CT, and it may affect CT through autonomic nervous system in exercising individuals by changing body temperature, systemic blood pressure, blood glucose, and blood concentrations of oxygen and CO2. The choroid also receives rich innervation from trigeminal sensory fibers, which contain calcitonin gene‑related peptide. They are thought to mediate light‑evoked control of the choroidal circulation. Furthermore, when dark‑adapted eyes were exposed to room light, choroidal blood flow increased.[4] Therefore, lighting and light intensity of the room are important factors during OCT measurements, and it is very likely that they affect the test results. Standard room lighting is particularly important for patients who will participate in studies. In conclusion, autonomic innervation and autoregulation of choroid are important for keeping the CT. The autoregulatory mechanisms of choroidal blood flow are extremely complex. The interplay of a number of systemic and local control mechanisms may be one of the major factors that affect the CT. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
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408
Indian Journal of Ophthalmology
Salih Uzun, Umit Yolcu1, Abdullah Ilhan1 Department of Ophthalmology, Etimesgut Military Hospital, 1 Department of Ophthalmology, Mevki Military Hospital, Ankara, Turkey Correspondence to: Dr. Salih Uzun, Eye Disease Service, Etimesgut Military Hospital, Ankara 06200, Turkey. E‑mail:
[email protected]
Vol. 64 No. 5
4. Fuchsjäger‑Mayrl G, Polska E, Malec M, Schmetterer L. Unilateral light‑dark transitions affect choroidal blood flow in both eyes. Vision Res 2001;41:2919‑24. 5. Buijs RM. The autonomic nervous system: A balancing act. Handb Clin Neurol 2013;117:1‑11. 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.
References
Access this article online
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.
Quick Response Code:
DOI: 10.4103/0301-4738.185634
2. Kur J, Newman EA, Chan‑Ling T. Cellular and physiological mechanisms underlying blood flow regulation in the retina and choroid in health and disease. Prog Retin Eye Res 2012;31:377‑406. 3. Alwassia AA, Adhi M, Zhang JY, Regatieri CV, Al‑Quthami A, Salem D, et al. Exercise‑induced acute changes in systolic blood pressure do not alter choroidal thickness as measured by a portable spectral‑domain optical coherence tomography device. Retina 2013;33:160‑5.
Comment on: The effect of anterior transposition of the inferior oblique muscle on eyelid configuration and function Sir, We congratulate Goncu et al. for their successful study entitled, “The effect of anterior transposition of the inferior oblique muscle on eyelid configuration and function.”[1] They evaluated the alteration of lower lid configuration and function with anterior transposition surgery of the inferior oblique (IO) muscle. In this study, the authors did not observe any significant effect on lower lid parameters with IO anterior transposition. We have read the article with great interest. It was stated that all measurements were performed by the same examiner, and to increase the reliability of the measurements, all were taken twice and the average value used. However, we think that intraclass correlation coefficient (ICC) would be a better choice to determine the repeated measures. ICC is commonly used as a measure of reliability.[2] We kindly ask the authors to evaluate all parameters with ICC for intraexaminer agreement, with the 95% confidence intervals and coefficient of variance as a separate table. We think that these results may show the repeatability and reliability of the measurements in a more satisfactory way. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
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Cite this article as: Uzun S, Yolcu U, Ilhan A. Comment on: Choroidal thickness changes after dynamic exercise as measured by spectral-domain optical coherence tomography. Indian J Ophthalmol 2016;64:407-8.
Onder Ayyildiz, Osman Melih Ceylan1, Fatih Mehmet Mutlu 1
Department of Ophthalmology, GATA Medical School, Ankara, Department of Ophthalmology, Inonu University, Malatya, Turkey Correspondence to: Dr. Onder Ayyildiz, Department of Ophthalmology, GATA Medical School, Ankara 06010, Turkey. E‑mail:
[email protected]
References 1. Goncu T, Cakmak S, Akal A, Oguz H. The effect of anterior transposition of the inferior oblique muscle on eyelid configuration and function. Indian J Ophthalmol 2016;64:33‑7. 2. Schuman JS, Pedut‑Kloizman T, Hertzmark E, Hee MR, Wilkins JR, Coker JG, et al. Reproducibility of nerve fiber layer thickness measurements using optical coherence tomography. Ophthalmology 1996;103:1889‑98. 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: 10.4103/0301-4738.185635 PMID: ***
Cite this article as: Ayyildiz O, Ceylan OM, Mutlu FM. Comment on: The effect of anterior transposition of the inferior oblique muscle on eyelid configuration and function. Indian J Ophthalmol 2016;64:408.
