We read with great interest the article by Keenan et al. “Associations between obstructive sleep apnoea, primary open angle glaucoma and age-related macular degeneration: record linkage study” (Br J Ophthalmol. 2017 Feb;101(2):155-159), which concluded that Obstructive Sleep Apnoea (OSA) is not associated with Primary Open Angle Glaucoma (POAG). Potential POAG aetiology inflammatory markers are higher in OSA patients, and glaucoma diagnosis is more common in OSA populations.
While retrospective studies have great value, it is important to account for risk-associated conditions, including family history of OSA, racial disparities [1], smoking, hypertension, floppy eyelids, Type II diabetes [2], COPD and obesity.
To determine a causal relationship between OSA and POAG, it is necessary to assess intraocular pressures/visual field progression before and after continuous positive airway pressure (CPAP) treatment, using prospective randomised control trial designs. Further, the OSA base rate in Keenan et al. was 2.5%, while the estimated OSA prevalence rate may exceed 20% for those over 55 years of age [3]. Missing 90+% of apnoea sufferers may have blurred the true apnoea-POAG relationship. The risk rate for apnoea in the first year after initial POAG episode was 1.5, but declined to less than 1.0 in subsequent years, which suggests the possibility of increasing neglect of apnoea risk over the course of POAG. These findings highlight the lack of OSA screening and...
We read with great interest the article by Keenan et al. “Associations between obstructive sleep apnoea, primary open angle glaucoma and age-related macular degeneration: record linkage study” (Br J Ophthalmol. 2017 Feb;101(2):155-159), which concluded that Obstructive Sleep Apnoea (OSA) is not associated with Primary Open Angle Glaucoma (POAG). Potential POAG aetiology inflammatory markers are higher in OSA patients, and glaucoma diagnosis is more common in OSA populations.
While retrospective studies have great value, it is important to account for risk-associated conditions, including family history of OSA, racial disparities [1], smoking, hypertension, floppy eyelids, Type II diabetes [2], COPD and obesity.
To determine a causal relationship between OSA and POAG, it is necessary to assess intraocular pressures/visual field progression before and after continuous positive airway pressure (CPAP) treatment, using prospective randomised control trial designs. Further, the OSA base rate in Keenan et al. was 2.5%, while the estimated OSA prevalence rate may exceed 20% for those over 55 years of age [3]. Missing 90+% of apnoea sufferers may have blurred the true apnoea-POAG relationship. The risk rate for apnoea in the first year after initial POAG episode was 1.5, but declined to less than 1.0 in subsequent years, which suggests the possibility of increasing neglect of apnoea risk over the course of POAG. These findings highlight the lack of OSA screening and documentation, particularly in POAG sufferers, which should be confirmed with hypoxia measures that might better correlate with OSA pathology than other OSA diagnostic indices [4]. OSA risk screening tools (Berlin, STOPBANG sleep apnoea questionnaires) are readily available, are fast and simple to administer and score, and show acceptable rates of concordance with sleep study evidence of OSA [5]. We thank Keenan et al. for their important work and recommend a National OSA Screening program for all, including POAG patients.
References
1. O'Connor GT, Lind BK, Lee ET, Nieto FJ, Redline S, Samet JM, Boland LL, Walsleben JA, Foster GL; Sleep Heart Health Study Investigators.. Variation in symptoms of sleep-disordered breathing with race and ethnicity: the Sleep Heart Health Study. Sleep. 2003 Feb 1;26(1):74-9.
2. S.D. West, D.J. Nicoll, J.R. Stradling, Prevalence of obstructive sleep apnoea in men with type 2 diabetes, Thorax 61 (2006) 945–950.
3. Young T, Palta M, Dempsey J, Skatrud J, Weber S, Badr S. The occurrence of sleep-disordered breathing among middle-aged adults. N Engl J Med. 1993 Apr 29;328(17):1230-5.
4. Bianchi MT, Russo K, Gabbidon H, Smith T, Goparaju B, Westover MB. Big data in sleep medicine: prospects and pitfalls in phenotyping. Nat Sci Sleep. 2017 Feb 16;9:11-29.
5. Nagappa M, Liao P, Wong J, Auckley D, Ramachandran SK, Memtsoudis S, Mokhlesi B, Chung F. Validation of the STOP-Bang Questionnaire as a Screening Tool for Obstructive Sleep Apnea among Different Populations: A Systematic Review and Meta-Analysis. PLoS One. 2015 Dec 14;10(12):e0143697.
I read with interest the article by Kuroda et al.[1] The authors
explored new possibilities of anterior segment imaging using a posterior
segment swept-source optical coherence tomography device without
noteworthy modifications. Interestingly, it was possible to obtain high-
resolution images of the conjunctiva, episclera, and the sclera near the
limbus that seemingly allow unequivocal identificati...
I read with interest the article by Kuroda et al.[1] The authors
explored new possibilities of anterior segment imaging using a posterior
segment swept-source optical coherence tomography device without
noteworthy modifications. Interestingly, it was possible to obtain high-
resolution images of the conjunctiva, episclera, and the sclera near the
limbus that seemingly allow unequivocal identification of anatomical
boundaries. The authors used this technique to examine eyes with anterior
scleritis/episcleritis.
However, I was not so impressed when I read through the methods
section of the paper. Contralateral eyes of patients were included as
controls. This is certainly problematic, considering that some of the
subjects had systemic inflammatory disease. In patients with overt
bilateral disease, both eyes were included in the analysis. As a result,
the measurements are not independent,[2] and the use of basic statistical
tests such as the Mann-Whitney or Kruskal-Wallis tests is not legitimate.
All these tests require independence of observations. Advanced statistical
methods[3] such as generalized estimating equations[4] or paired
comparison[5] would be necessary to obtain statistically valid results.
Another significant weakness of the methodology is that the thickness
of tissues was not measured perpendicularly to the ocular surface. This
makes data prone to bias and increases the variability. Moreover, the
internal limits of the sclera in Figures 2B and 4B are not very distinct,
and one wonders how accurate the measurements of this boundary are in
other eyes in the study, if these photos are representative.
To sum up, the images displayed are promising, yet, the scientific
rigour of the paper is much less compelling.
References
1. Kuroda Y, Uji A, Morooka S, et al. Morphological features in
anterior scleral inflammation using swept-source optical coherence
tomography with multiple B-scan averaging. Br J Ophthalmol Published
Online First: 7 July 2016. doi: 10.1136/bjophthalmol-2016-308561
2. Ray WA, O'Day DM. Statistical analysis of multi-eye data in
ophthalmic research. Invest Ophthalmol Vis Sci 1985; 26:1186-8.
3. Fan Q, Teo YY, Saw SM. Application of advanced statistics in
ophthalmology. Invest Ophthalmol Vis Sci 2011; 52:6059-65.
4. Hanley JA, Negassa A, Edwardes MD, et al. Statistical analysis of
correlated data using generalized estimating equations: an orientation. Am
J Epidemiol 2003; 157:364-75.
5. Murdoch IE, Morris SS, Cousens SN. People and eyes: statistical
approaches in ophthalmology. Br J Ophthalmol 1998; 82:971-3.
We thank Dr. Ebneter for his interest in our article.1 He pointed out
that we included contralateral eyes of unilateral diseased eyes as control
eyes and both eyes of bilateral affected eyes were included as diseased
eyes. Accordingly, we performed additional analyses. We excluded
contralateral eyes from control eyes and included only right eyes of
bilateral affected eyes as diseased eyes. As a resul...
We thank Dr. Ebneter for his interest in our article.1 He pointed out
that we included contralateral eyes of unilateral diseased eyes as control
eyes and both eyes of bilateral affected eyes were included as diseased
eyes. Accordingly, we performed additional analyses. We excluded
contralateral eyes from control eyes and included only right eyes of
bilateral affected eyes as diseased eyes. As a result, the average
thicknesses of conjunctival epithelium, conjunctival stroma/episclera
complex, and scleral stroma were 55.4?8.8, 288.0?44.4, and 434.2?60.1 ?m
in the control group, 52.2?8.8, 320.7?48.6, and 455.8?43.4 ?m in diffuse
episcleritis, 79.6?28.8, 450.7?138.3, and 469.5?41.7 ?m in diffuse
scleritis, respectively. Significant differences could be found in
conjunctival epithelium and conjunctival stroma/episclera complex among
the three groups (p=0.002, 0.001, Kruskal-Wallis test), but not in scleral
stroma (p=0.231). In diffuse scleritis, conjunctival epithelium and
conjunctival stroma/episclera complex were significantly thicker than in
controls (p=0.013 and 0.002). These results showed the same tendency as
the original results.
Second, Dr. Ebneter pointed out the weakness of the method, which is
that the thickness is measured vertically but not perpendicularly to the
ocular surface. We agree with him that this measurement method was crude
and moderately inaccurate. Unfortunately, we could not measure the
thickness in a direction perpendicular to conjunctival epithelium because
SS-OCT was used for the posterior segment. Moreover, he indicated that the
borders of the sclera in Figure 2B and 4B were vague. Indeed, it may not
be easy to clearly distinguish scleral stroma and episclera. Severe
thickening in the conjunctival stroma and episcleral layer may make the
border indistinct. However, the point of this article, which is that
thickening occurred mainly in the episclera rather than in the scleral
stroma in diffuse scleritis, was meaningful, even if the measurements were
crude.
References
1. Kuroda Y, Uji A, Morooka S, et al. Morphological features in
anterior scleral inflammation using swept-source optical coherence
tomography with multiple B-scan averaging. Br J Ophthalmol 2016. doi:
10.1136/bjophthalmol-2016-308561.
We read the article titled "Outcome of two-muscle surgery for large-
angle intermittent exotropia in children" by the authors Ki Won Jin and
Dong Gyu Choi with great enthusiasm.1 The authors have compared the
success of two muscle surgery for large angle (>=40 Prism Diopters
(PD)) vs moderate-angle (>=20 and <30PD) intermittent exotropia.
Neither of the two ranges described, include deviation between 30 to 39PD....
We read the article titled "Outcome of two-muscle surgery for large-
angle intermittent exotropia in children" by the authors Ki Won Jin and
Dong Gyu Choi with great enthusiasm.1 The authors have compared the
success of two muscle surgery for large angle (>=40 Prism Diopters
(PD)) vs moderate-angle (>=20 and <30PD) intermittent exotropia.
Neither of the two ranges described, include deviation between 30 to 39PD.
Whether these deviations were excluded or this is a typographical error is
subject to speculation. The range of exotropia in the large angle group
was upto 70PD. Several prior studies have shown that success rates of two
muscle surgery drop down significantly as the exotropia increases beyond
50PD2 and therefore three or four muscle surgery is recommended.3
Including such larger deviations skews the data and the chances of failure
automatically increases in Group A of the study. We believe that a better
comparison would have been between the moderate angle group and a second
group of 35 - 50PD.
None of the patients in the above study had symptomatic diplopia in
lateral gaze or palpebral fissure changes at any postoperative visit in
spite of performing large 9.5mm lateral rectus recession and 7mm medial
rectus recession in at least some of the patients. This observation is
unlike prior observations4 and our experience too with large recess-resect
surgery. Lastly the authors have not compared the two groups in terms of
refractive error which is an important factor leading to variations in
preoperative measurement of deviation and the effect of surgery.5
Nonetheless we would like to congratulate the authors for conducting this
important study that probably suggests that large angle intermittent
exotropia warrants more than two horizontal rectus muscle surgery in order
to achieve motor success in majority of patients.
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...
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.
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...
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.
Dear Editor,
We have read and reviewed the article entitled as "Diurnal variations in
luminal and stromal areas of choroid in normal eyes'' by Kinoshita et al.
with great interest [1]. The authors analyzed systemic blood pressure,
heart rate, intraocular pressure, central choroidal thickness (CCT), total
cross-sectional choroidal area, the luminal areas, stromal areas and the
ratio of luminal area to total choroidal area...
Dear Editor,
We have read and reviewed the article entitled as "Diurnal variations in
luminal and stromal areas of choroid in normal eyes'' by Kinoshita et al.
with great interest [1]. The authors analyzed systemic blood pressure,
heart rate, intraocular pressure, central choroidal thickness (CCT), total
cross-sectional choroidal area, the luminal areas, stromal areas and the
ratio of luminal area to total choroidal area (L/C ratio) of 38 healthy
participants every 3 hours between 06:00 and 21:00. They found that there
were significant diurnal variations in the CCT, total choroidal area,
luminal area and L/C ratio with the maximum values at 6:00 hours and the
minimum values at 15:00 hours. We express our gratitude to the authors,
and appreciate their valuable contributions to the literature. However, we
would like to ask the authors two important points regarding the study.
Choroid is the most vascular structure of the eye, and it has the
highest blood flow of any tissue per unit weight in human body.
Additionally, numerous studies have demonstrated that choroid has a unique
anatomical structure, and neurovascular configuration [2]. Owing to
advancements in technology, ability to obtain fast, high-resolution, high-
quality imaging of choroid with reproducible results made the
investigators to focus on this important structure.
Kinoshita et al. investigated the choroid, and the relationship of
structure of choroid with systemic and local factors, and demonstrated the
diurnal variation of those parameters. They compared all those
investigated parameters, and particularly the parameters measured between
06:00 and 15:00 with each other. It is a fact that the vast majority of
the studies investigating the choroid were performed during working hours.
Accordingly, we would like to ask the authors whether they investigated
the parameters, particularly the ones related to choroid in different time
intervals, for instance between 09:00 and 12:00, or 09:00 and 15:00, or
12:00 and 15:00; since we suppose that such an assessment may guide
investigators for further studies on choroid.
Second, we suggest that considering age and gender differences of the
participants regarding choroid-related parameters might provide
significant contribution to the paper and the literature.
References
1 Kinoshita T, Mitamura Y, Shinomiya K, et al. Diurnal variations in
luminal and stromal areas of choroid in normal eyes. Br J Ophthalmol 2016;
doi: 10.1136/bjophthalmol-2016-308594.
2 Nickla DL, Wallman J. The multifunctional choroid. Prog Retin Eye Res
2010;29:144-68.
We thank Drs. Uzun and Pehlivan for their interest and comments to
our article.[1]
We compared and correlated the central choroidal thickness to the
different choridal parameters at different times between 9:00 h and 18:00
h. We compared the findings between 09:00 h and 12:00 h, 09:00 h and 15:00
h, 09:00 h and 18:00 h, 12:00 h and 15:00 h, 12:00 h and 18:00 h, and
15:00 h and 18:00 h. There were...
We thank Drs. Uzun and Pehlivan for their interest and comments to
our article.[1]
We compared and correlated the central choroidal thickness to the
different choridal parameters at different times between 9:00 h and 18:00
h. We compared the findings between 09:00 h and 12:00 h, 09:00 h and 15:00
h, 09:00 h and 18:00 h, 12:00 h and 15:00 h, 12:00 h and 18:00 h, and
15:00 h and 18:00 h. There were significant strong correlations between
the fluctuation range of central choroidal thickness (fCCT) and those of
luminal area and total choroidal area at all times (r >0.8, P
<0.001). There was no significant correlation between the fCCT and the
fluctuation range of stromal area (fSA) at 09:00 h and 18:00 h, 12:00 h
and 18:00 h, and 15:00 h and 18:00 h (P >0.1). There were significant
correlations between the fCCT and the fSA at 09:00 h and 12:00 h, 09:00 h
and 15:00 h but the correlations were relatively weak (r = 0.428, P =
0.010; r = 0.383, P = 0.023; respectively). There was a moderate
correlation between fCCT and fSA at 12:00 h and 15:00 h (r = 0.635, P
<0.001), however, no significant difference in the mean choroidal
parameters was found during this interval (P = 1.000 for all choroidal
parameters, repeated ANOVA with the Bonferroni test for post hoc
analysis). Thus, these results reconfirm our main conclusion that that the
diurnal variations in the choroidal thickness are mainly due to the
fluctuations in the luminal area.
There was no significant correlation between age and the choroidal
parameters in the partial regression analyses in which the axial length
was set as the control variable. However, we reported earlier that the age
was significantly and negatively correlated with the total choroidal area,
luminal area, stromal area, and the ratio of luminal to stromal area.[2]
The differences in the distribution of age of the participants and the
sample size between the two studies may explain this discrepancy. The
mean age of 30.5 ? 9.11 (mean ? SD) years (range, 21 - 52 years) in the
present study was younger with a smaller range than that in the previous
report with a mean age of 55.9 ? 18.8 years (range 22 - 90 years). The
sample size of the previous study was 180 which was larger than that of
the present study (n = 38). No significant difference in the choroidal
parameters was found between the sexes.
Again, we thank you for your interest.
1. 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. doi: 10.1136/bjophthalmol-2016-
308594.
2. Sonoda S, Sakamoto T, Yamashita T, et al. Luminal and stromal areas of
choroid determined by binarization method of optical coherence tomographic
images. Am J Ophthalmol 2015;159:1123-31.
Dear Editor,
We have read and reviewed the article entitled "The role of enhanced depth
imaging optical coherence tomography in chronic Vogt-Koyanagi-Harada
disease''which was written by Jap and Chee with great interest [1]. The
authors evaluated 52 patients with chronic Vogt-Koyanagi-Harada (VKH)
disease using indocyanine green angiograms (ICGAs) and optical coherence
tomography (OCT). They discovered that the subfoveal...
Dear Editor,
We have read and reviewed the article entitled "The role of enhanced depth
imaging optical coherence tomography in chronic Vogt-Koyanagi-Harada
disease''which was written by Jap and Chee with great interest [1]. The
authors evaluated 52 patients with chronic Vogt-Koyanagi-Harada (VKH)
disease using indocyanine green angiograms (ICGAs) and optical coherence
tomography (OCT). They discovered that the subfoveal choroidal thickness
(SFCT) was thinner when ICGA was calm and thicker when the ICGA was
active. Jap and Chee suggested that the positive correlation of SFCT
measurements with ICGA score supporting that it might be used to monitor
disease activity in chronic VKH in addition to ICGA, possibly reducing the
number of ICGAs required. We would like to congratulate the authors for
the valuable studies of them and ask them to give more details and
contribute to the article.
Firstly, choroidal thickness (CT) gets affected from various local
and systemic factors. For example, many local diseases (glaucoma, age-
related macular degeneration, strabismus, etc.), and systemic diseases
(diabetes mellitus, hypertension, hyperlipidemia, vasculapathies, etc.)
and physiological conditions (such as menstrual cycle and pregnancy) may
have an effect on CT. Average age of 52 patients have been mentioned to be
51.7?14.1 years and 26 of them have been mentioned to be females. We would
like to ask the authors if they have taken local/systemic diseases and
their drug used for their treatment and physiological conditions of the
patients into consideration.
Secondly, it is known that many factors in relation with eyes such as
axial length of eye, intraocular pressure, and refractive error certainly
affect CT [2,3]. We think that these parameters must be stated in the
article.
Thirdly, we also would like to learn body mass indexes, systemic
blood pressure measurements, fasting and postprandial, sleeping and
exercising conditions of the patients, and their consumption of
caffeinated/non-caffeinated beverages before OCT measurements, since all
these parameters are known to be apparently affecting CT [2,3].
Fourthly, CT demonstrates considerable diurnal alteration. The
thickness of choroid is able to increase by 50% in an hour, and increase
its thickness by four times in few days [2]. It has been demonstrated by
Kee et al. that the choroid can get thinner very fast, by about 100
micrometer in 3-4 hours in chicks [4]. CT in 12 healthy humans was
measured in another prospective study by Tan et al. with intervals of two
hours between 9:00 AM-5:00 PM on two different days, and significant
differences in CT were determined within all measurement points [5]. It
has been found by Tan et al. that mean diurnal amplitude of CT was
33.7?21.5 micrometer (range: 3-67 micrometer). The alteration in CT was
also correlated with alterations in systemic blood pressure.
In consideration of those literature data, we are of the opinion that
all local and systemic factors must be considered in the studies in which
CT is evaluated.
Competing interests: None
References
1 Jap A. Chee S-P. The role of enhanced depth imaging optical
coherence tomography in chronic Vogt-Koyanagi-Harada disease. Br J
Ophthalmol 2016;0:1-4.
2 Nickla DL, Wallman J. The multifunctional choroid. Prog Retin Eye Res
2010;29:144-68.
3 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.
4 Kee CS, Marzani D, Wallman J. Differences in time course and visual
requirements of ocular responses to lenses and diffusers. Invest
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5 Tan CS, Ouyang Y, Ruiz H, Sadda SR. Diurnal variation of choroidal
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We thank Uzun and Pehlivan for their interest in our article1 and
their comments. They raise various factors that are potential confounders
of subfoveal choroidal thickness measurements. As our study was a
retrospective review of paired samples of enhanced depth imaging optical
coherence tomography (EDI-OCT) and indocyanine green angiography (ICGA) in
the right eye of patients with chronic Vogt-Koya...
We thank Uzun and Pehlivan for their interest in our article1 and
their comments. They raise various factors that are potential confounders
of subfoveal choroidal thickness measurements. As our study was a
retrospective review of paired samples of enhanced depth imaging optical
coherence tomography (EDI-OCT) and indocyanine green angiography (ICGA) in
the right eye of patients with chronic Vogt-Koyanagi-Harada disease (VKH),
we were unable to control for these factors. We recognize the limitations
of a retrospective study and thus we advocated longitudinal studies to
derive a more precise correlation between EDI-OCT and ICGA grade and hence
its utility in monitoring chronic VKH.
Soon-Phaik Chee and Aliza Jap
References
1 Jap A. Chee S-P. The role of enhanced depth imaging optical coherence
tomography in chronic Vogt-Koyanagi-Harada disease. Br J Ophthalmol
2016;0:1-4
We read with great interest the article by Keenan et al. “Associations between obstructive sleep apnoea, primary open angle glaucoma and age-related macular degeneration: record linkage study” (Br J Ophthalmol. 2017 Feb;101(2):155-159), which concluded that Obstructive Sleep Apnoea (OSA) is not associated with Primary Open Angle Glaucoma (POAG). Potential POAG aetiology inflammatory markers are higher in OSA patients, and glaucoma diagnosis is more common in OSA populations.
While retrospective studies have great value, it is important to account for risk-associated conditions, including family history of OSA, racial disparities [1], smoking, hypertension, floppy eyelids, Type II diabetes [2], COPD and obesity.
To determine a causal relationship between OSA and POAG, it is necessary to assess intraocular pressures/visual field progression before and after continuous positive airway pressure (CPAP) treatment, using prospective randomised control trial designs. Further, the OSA base rate in Keenan et al. was 2.5%, while the estimated OSA prevalence rate may exceed 20% for those over 55 years of age [3]. Missing 90+% of apnoea sufferers may have blurred the true apnoea-POAG relationship. The risk rate for apnoea in the first year after initial POAG episode was 1.5, but declined to less than 1.0 in subsequent years, which suggests the possibility of increasing neglect of apnoea risk over the course of POAG. These findings highlight the lack of OSA screening and...
Show MoreDear Editor,
I read with interest the article by Kuroda et al.[1] The authors explored new possibilities of anterior segment imaging using a posterior segment swept-source optical coherence tomography device without noteworthy modifications. Interestingly, it was possible to obtain high- resolution images of the conjunctiva, episclera, and the sclera near the limbus that seemingly allow unequivocal identificati...
Dear Editor:
We thank Dr. Ebneter for his interest in our article.1 He pointed out that we included contralateral eyes of unilateral diseased eyes as control eyes and both eyes of bilateral affected eyes were included as diseased eyes. Accordingly, we performed additional analyses. We excluded contralateral eyes from control eyes and included only right eyes of bilateral affected eyes as diseased eyes. As a resul...
We read the article titled "Outcome of two-muscle surgery for large- angle intermittent exotropia in children" by the authors Ki Won Jin and Dong Gyu Choi with great enthusiasm.1 The authors have compared the success of two muscle surgery for large angle (>=40 Prism Diopters (PD)) vs moderate-angle (>=20 and <30PD) intermittent exotropia. Neither of the two ranges described, include deviation between 30 to 39PD....
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...
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...
Dear Editor, We have read and reviewed the article entitled as "Diurnal variations in luminal and stromal areas of choroid in normal eyes'' by Kinoshita et al. with great interest [1]. The authors analyzed systemic blood pressure, heart rate, intraocular pressure, central choroidal thickness (CCT), total cross-sectional choroidal area, the luminal areas, stromal areas and the ratio of luminal area to total choroidal area...
Dear Editor,
We thank Drs. Uzun and Pehlivan for their interest and comments to our article.[1] We compared and correlated the central choroidal thickness to the different choridal parameters at different times between 9:00 h and 18:00 h. We compared the findings between 09:00 h and 12:00 h, 09:00 h and 15:00 h, 09:00 h and 18:00 h, 12:00 h and 15:00 h, 12:00 h and 18:00 h, and 15:00 h and 18:00 h. There were...
Dear Editor, We have read and reviewed the article entitled "The role of enhanced depth imaging optical coherence tomography in chronic Vogt-Koyanagi-Harada disease''which was written by Jap and Chee with great interest [1]. The authors evaluated 52 patients with chronic Vogt-Koyanagi-Harada (VKH) disease using indocyanine green angiograms (ICGAs) and optical coherence tomography (OCT). They discovered that the subfoveal...
Dear Editor,
We thank Uzun and Pehlivan for their interest in our article1 and their comments. They raise various factors that are potential confounders of subfoveal choroidal thickness measurements. As our study was a retrospective review of paired samples of enhanced depth imaging optical coherence tomography (EDI-OCT) and indocyanine green angiography (ICGA) in the right eye of patients with chronic Vogt-Koya...
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