Indian Journal of Ophthalmology

LETTER TO THE EDITOR
Year
: 2015  |  Volume : 63  |  Issue : 12  |  Page : 930-

Temperature control role of the choroid may affect choroidal thickness after dynamic exercise


Yildiray Yildirim, Abdullah Kaya, Taner Kar 
 Department of Ophthalmology, GATA HaydarpasaTraining Hospital, Istanbul, Turkey

Correspondence Address:
Dr. Abdullah Kaya
Department of Ophthalmology, GATA Haydarpasa Training Hospital, Istanbul
Turkey




How to cite this article:
Yildirim Y, Kaya A, Kar T. Temperature control role of the choroid may affect choroidal thickness after dynamic exercise.Indian J Ophthalmol 2015;63:930-930


How to cite this URL:
Yildirim Y, Kaya A, Kar T. Temperature control role of the choroid may affect choroidal thickness after dynamic exercise. Indian J Ophthalmol [serial online] 2015 [cited 2020 Apr 4 ];63:930-930
Available from: http://www.ijo.in/text.asp?2015/63/12/930/176033


Full Text

Dear Sir,

We read the current article, "choroidal thickness (CT) changes after dynamic exercise as measured by spectral-domain optical coherence tomography," with interest.[1] In this well-organized study, authors have investigated CT to be increased when measured 5 min after exercise and normalized at measurement after 15 min. Results are being discussed very well. Besides, we want to make some contributions that may widen discussion area on these findings.

As authors addressed in introduction, choroid is believed to have a role in temperature regulation.[2] Choroid has highest blood flow in the body. Its blood flow is 10 times higher than blood flow through gray matter of brain.[3] However, this high blood flow does not correspond to metabolic requirements. High blood flow of the choroid is believed to protect retina from heat stress.[4] Body temperature rises during exercise. Elevated temperature may harm sensitive retinal cells such as photoreceptors and retina pigment epithelium. Although body temperature is being controlled by hypothalamus during exercise, increase in choroidal blood flow may contribute to this process to protect retina. Retina may need an extra heat lowering mechanism during exercise because of its sensitive structure and heat storing potential of the vitreous. As a result, increase in choroidal blood flow and thereby CT is an expected result. We believe that, finding in this study should also be discussed according to retinal cooling. On the other hand, in a study, CT have found not to be changed by exercise.[5] Average age of patients in this study is 60.6 (±10.4 years) while 27 ± 4.08 in the current study. Age may affect changes in CT.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Sayin 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.
2Nickla DL, Wallman J. The multifunctional choroid. Prog Retin Eye Res 2010;29:144-68.
3Alm A, Bill A, Young FA. The effects of pilocarpine and neostigmine on the blood flow through the anterior uvea in monkeys. A study with radioactively labelled microspheres. Exp Eye Res 1973;15:31-6.
4Parver LM, Auker C, Carpenter DO. Choroidal blood flow as a heat dissipating mechanism in the macula. Am J Ophthalmol 1980;89:641-6.
5Alwassia 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.