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• Re:Comment on: Choroidal structure in eyes with drusen and reticular pseudodrusen determined by binarisation of optical coherence tomographic images
  Giuseppe Querques
  Published on: 22 February 2017
• Comment on: Choroidal structure in eyes with drusen and reticular pseudodrusen determined by binarisation of optical coherence tomographic images
  Salih Uzun
  Published on: 22 February 2017

• Published on: 22 February 2017

  Re:Comment on: Choroidal structure in eyes with drusen and reticular pseudodrusen determined by binarisation of optical coherence tomographic images

  • Giuseppe Querques, Head Medical Retina & Imaging Unit
  • Other Contributors:
    • Federico Corvi

  Dear Editor We thank Drs Uzun and Pehlivan for their interest in our article,1 and we welcome this opportunity to address their concerns. As pointed out, there are several factors that may induce fluctuation of choroidal thickness such as the diurnal effect, systemic diseases (endocrine, cardiovascular, rheumatologic, and inflammatory), intraocular pressure, refractive status, systemic blood pressure, body mass index, a...

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  Dear Editor We thank Drs Uzun and Pehlivan for their interest in our article,1 and we welcome this opportunity to address their concerns. As pointed out, there are several factors that may induce fluctuation of choroidal thickness such as the diurnal effect, systemic diseases (endocrine, cardiovascular, rheumatologic, and inflammatory), intraocular pressure, refractive status, systemic blood pressure, body mass index, alcohol, smoking, and caffeinated beverage consuming.2-8 A limitation of our study is the retrospective design, therefore all of these parameters cannot be tested. In our series, the refractive error should not be considered as a potential confounding factor because we included patients with an axial length between 23.5 and 26.5 mm. Regarding intraocular pressure, a recent study 5 showed a significant diurnal fluctuation, but no correlation with choroidal thickness was detected in other reports.3,7 All of the studies 2-8 determining the diurnal variation of choroidal thickness were conducted in healthy subjects with healthy choroid while in our series we evaluated patients with drusen and reticular pseudodrusen in which remodeling of the choroid has been demonstated.1,9 In particular in patients with reticular pseudodrusen the choroid is significantly thinner compared to control subjects.1,9 As a result, thinner choroid with less blood supply may be less influenced by diurnal variation or systemic, local and environmental factors. Of note, a recent publication evaluated the diurnal variations in luminal and stromal areas of choroid in normal eyes by binarisation technique and demonstrated significant variations in the central choroidal thickness and luminal area but not in the stromal area.9 In our study we found that the stromal area was more represented in eyes with reticular pseudodrusen, suggesting less influence by diurnal variation or systemic, local and environmental factors and a possible role of choroidal vascular depletion and fibrotic replacement in the pathogenesis and disease progression.1 The insightful comments of Drs Uzun and Pehlivan are worth of considerable for further prospective studies with larger sample size, especially in patients with early age related macular degeneration and reticular pseudodrusen, and longer follow-up periods are needed to confirm if systemic, local and environmental factors should be considered as potential confunding effects on the choroid examination. ? References 1. Corvi F, Souied EH, Capuano V, et al. Choroidal structure in eyes with drusen and reticular pseudodrusen determined by binarisation of optical coherence tomographic images. Br J Ophthalmol. 2016. pii: bjophthalmol- 2016-308548. 2. Tan KA, Gupta P, Agarwal A, Chhablani J, Cheng CY, Keane PA, et al. State of science: Choroidal thickness and systemic health. Surv Ophthalmol 2016; doi: 10.1016/j.survophthal.2016.02.007. 3. Toyokawa N, Kimura H, Fukomoto A, Kuroda S. Difference in morning and evening choroidal thickness in Japanese subjects with no chorioretinal disease. Ophthalmic Surg Lasers Imaging. 2012;43:109e14 4. Usui S, Ikuno Y, Akiba M, Maruko I, Sekiryu T, Nishida K, et al. Circadian changes in subfoveal choroidal thickness and the relationship with circulatory factors in healthy subjects. Invest Ophthalmol Vis Sci 2012;53:2300-7. 5. Lee SW, Yu SY, Seo KH, Kim ES, Kwak HW. Diurnal variation in choroidal thickness in relation to sex, axial length, and baseline choroidal thickness in healthy Korean subjects. Retina 2014;34:385-93. 6. Chakraborty R, Read SA, Collins MJ. Diurnal variations in axial length, choroidal thickness, intraocular pressure, and ocular biometrics. Invest Ophthalmol Vis Sci. 2011;52:5121e9. 7. Tan CS, Ouyang Y, Ruiz H, Sadda SR. Diurnal variation of choroidal thickness in normal, healthy subjects measured by spectral domain optical coherence tomography. Invest Ophthalmol Vis Sci. 2012;53:261e6 8. Kinoshita T, Mitamura Y, Shinomiya K, et al. Diurnal variations in luminal and stromal areas of choroid in normal eyes. Br J Ophthalmol. 2016 Jun 13. pii: bjophthalmol-2016-308594.6 9. Querques G, Querques L, Forte R, et al. Choroidal changes associated with reticular pseudodrusen. Invest Ophthalmol Vis Sci 2012;53:1258-63.

  Conflict of Interest:

  None declared

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  Conflict of Interest:
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• Published on: 22 February 2017

  Comment on: Choroidal structure in eyes with drusen and reticular pseudodrusen determined by binarisation of optical coherence tomographic images

  • Salih Uzun, M.D.
  • Other Contributors:
    • Emre Pehlivan

  Dear Editor, We have read and reviewed the article entitled as "Choroidal structure in eyes with drusen and reticular pseudodrusen determined by binarisation of optical coherence tomographic images" by Corvi et al. with great interest [1]. The authors compared luminal and stromal areas of the choroid in eyes with drusen and reticular pseudodrusen (RPD), and investigated their changes over 24 months using optical coherenc...

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  Dear Editor, We have read and reviewed the article entitled as "Choroidal structure in eyes with drusen and reticular pseudodrusen determined by binarisation of optical coherence tomographic images" by Corvi et al. with great interest [1]. The authors compared luminal and stromal areas of the choroid in eyes with drusen and reticular pseudodrusen (RPD), and investigated their changes over 24 months using optical coherence tomography (OCT). They found that the mean total choroidal, luminal, and stromal areas decreased similarly in eyes with drusen and RPD over the period of 24 months. The mean total choroidal, luminal, and stromal areas were reduced more in eyes with RPD when compared to the eyes with drusen, and the controls. We express our gratitude to the authors for this valuable study, and we would like to ask the authors some important points that may affect the study results.

  Owing to its unique anatomic structure, choroid is one of the most excessively vascularized tissues in the body. Accordingly, various local, systemic or environmental factors that affect vascular system influence choroid [2,3]. Although Corvi et al. referred a number of factors affecting choroid, we suggest that some important points should also be addressed in the paper.

  First, choroidal thickness (CT) has a significant diurnal variation. Animal studies have demonstrated that CT might increase up to 50% in an hour, and might decrease 100 ?m within 3-4 hours [3]. In a study, Usui et al. analyzed subfoveal CT of healthy individuals at three hours intervals, and discovered that CT demonstrated significant differences at all measurement points [4]. In that study, Usui et al. indicated that diurnal variation in CT might be up to 65 ?m (ranging between 8 and 65 ?m). Another study by Lee et al. that included 100 adults reported the mean amplitude of the diurnal variation in CT as 20.32 ? 10.40 ?m (ranging between 4 and 60 ?m) [5]. Therefore we would like to ask the authors whether they have considered diurnal variation of CT at baseline, and 24- month choroid measurements.

  Second, various systemic diseases (endocrine, cardiovascular, rheumatologic, and inflammatory), and their medications may significantly affect CT [2]. Since the participants of the study are old, those points should be indicated in the paper.

  Third, intraocular pressure and refractive status, which have well known effects on CT, should be indicated in the paper, and compared between the groups.

  Fourth, we suggest that some important parameters that affect CT like systemic blood pressure, and body mass index of the participants should also be addressed in the paper. Moreover, alcohol, smoking, and caffeinated beverage consuming of the participants should be asked for before OCT measurements.

  In summary, we suggest that the aforementioned factors affecting CT may also affect stromal and luminal areas of the choroid as well, and change the results of the study. We want to get the opinions of the authors in this regard.

  References 1 Corvi F, Souied EH, Capuano V, Costanzo E, Benatti L, Querques L, et al. Choroidal structure in eyes with drusen and reticular pseudodrusen determined by binarisation of optical coherence tomographic images. Br J Ophthalmol. 2016; doi: 10.1136/bjophthalmol-2016-308548. 2 Tan KA, Gupta P, Agarwal A, Chhablani J, Cheng CY, Keane PA, et al. State of science: Choroidal thickness and systemic health. Surv Ophthalmol 2016; doi: 10.1016/j.survophthal.2016.02.007. 3 Nickla DL, Wallman J. The multifunctional choroid. Prog Retin Eye Res 2010;29:144-68. 4 Usui S, Ikuno Y, Akiba M, Maruko I, Sekiryu T, Nishida K, et al. Circadian changes in subfoveal choroidal thickness and the relationship with circulatory factors in healthy subjects. Invest Ophthalmol Vis Sci 2012;53:2300-7. 5 Lee SW, Yu SY, Seo KH, Kim ES, Kwak HW. Diurnal variation in choroidal thickness in relation to sex, axial length, and baseline choroidal thickness in healthy Korean subjects. Retina 2014;34:385-93.

  Conflict of Interest:

  None declared

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  Conflict of Interest:
  None declared.

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