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Dark adaptation in relation to choroidal thickness in healthy young subjects: a cross-sectional, observational study.

Munch IC, Altuntas C, Li XQ, Jackson GR, Klefter ON, Larsen M - BMC Ophthalmol (2016)

Bottom Line: There was no significant correlation between any of the two measures of rod-mediated dark adaptation and choroidal thickness (time to rod intercept versus choroidal thickness 0.072 (CI95 -0.23 to 0.38) min/100 μm, P = 0.64, adjusted for age and sex).Choroidal thickness, refraction and ocular axial length had no detectable effect on rod-mediated dark adaptation in healthy young subjects.Our results do not support that variations in dark adaptation can be attributed to variations in choroidal thickness.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Zealand University Hospital, Sygehusvej 10, DK-4000, Roskilde, Denmark. icm@dadlnet.dk.

ABSTRACT

Background: Dark adaptation is an energy-requiring process in the outer retina nourished by the profusely perfused choroid. We hypothesized that variations in choroidal thickness might affect the rate of dark adaptation.

Method: Cross-sectional, observational study of 42 healthy university students (mean age 25 ± 2.0 years, 29 % men) who were examined using an abbreviated automated dark adaptometry protocol with a 2° diameter stimulus centered 5° above the point of fixation. The early, linear part of the rod-mediated dark adaptation curve was analyzed to extract the time required to reach a sensitivity of 5.0 × 10(-3) cd/m2 (time to rod intercept) and the slope (rod adaptation rate). The choroid was imaged using enhanced-depth imaging spectral-domain optical coherence tomography (EDI-OCT).

Results: The time to the rod intercept was 7.3 ± 0.94 (range 5.1 - 10.2) min. Choroidal thickness 2.5° above the fovea was 348 ± 104 (range 153-534) μm. There was no significant correlation between any of the two measures of rod-mediated dark adaptation and choroidal thickness (time to rod intercept versus choroidal thickness 0.072 (CI95 -0.23 to 0.38) min/100 μm, P = 0.64, adjusted for age and sex). There was no association between the time-to-rod-intercept or the dark adaptation rate and axial length, refraction, gender or age.

Conclusion: Choroidal thickness, refraction and ocular axial length had no detectable effect on rod-mediated dark adaptation in healthy young subjects. Our results do not support that variations in dark adaptation can be attributed to variations in choroidal thickness.

No MeSH data available.


Related in: MedlinePlus

Dark adaptation in relation to choroidal thickness in 42 healthy, young subjects. The speed of dark adaptation was measured as the time to reach a predefined sensitivity threshold (the rod intercept). The slope of the regression line is 0.076 (CI95−0.21 to 0.37) min/100μm (P = 0.64, adjusted for age and sex)
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Fig2: Dark adaptation in relation to choroidal thickness in 42 healthy, young subjects. The speed of dark adaptation was measured as the time to reach a predefined sensitivity threshold (the rod intercept). The slope of the regression line is 0.076 (CI95−0.21 to 0.37) min/100μm (P = 0.64, adjusted for age and sex)

Mentions: Time to rod intercept was normally distributed with a mean of 7.3 min ± 0.94 (range 5.1–10 min) and comparable between men and women (Table 1). An example of a dark adaptation curve from one of the participants is provided in Fig. 1. There was no significant correlation between time to rod intercept or rod adaptation rate and choroidal thickness with the linear regression coefficient for time to rod intercept being 0.072 (CI95−0.21 to 0.37, P = 0.64) min per 100 μm increase in choroidal thickness, adjusted for age and sex (Fig. 2, Table 2). When the choroidal thickness was included as a dichotomous variable (choroidal thickness greater or smaller than the median of 359 μm) the rod intercept was numerically 0.29 min (CI95 0.25–0.30 min) longer in the eyes with the thicker choroids (P = 0.57 adjusted for age and sex) (data not tabulated). There was no significant association between the rod-mediated dark adaptation (time to rod intercept, rod adaptation rate) and age, sex, refractive error, axial length or blood pressure (Table 2). Including refraction, axial length and the blood pressure in the analyses of the correlation of time to rod intercept and choroidal thickness did not alter the results (data not tabulated).Fig. 2


Dark adaptation in relation to choroidal thickness in healthy young subjects: a cross-sectional, observational study.

Munch IC, Altuntas C, Li XQ, Jackson GR, Klefter ON, Larsen M - BMC Ophthalmol (2016)

Dark adaptation in relation to choroidal thickness in 42 healthy, young subjects. The speed of dark adaptation was measured as the time to reach a predefined sensitivity threshold (the rod intercept). The slope of the regression line is 0.076 (CI95−0.21 to 0.37) min/100μm (P = 0.64, adjusted for age and sex)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4940899&req=5

Fig2: Dark adaptation in relation to choroidal thickness in 42 healthy, young subjects. The speed of dark adaptation was measured as the time to reach a predefined sensitivity threshold (the rod intercept). The slope of the regression line is 0.076 (CI95−0.21 to 0.37) min/100μm (P = 0.64, adjusted for age and sex)
Mentions: Time to rod intercept was normally distributed with a mean of 7.3 min ± 0.94 (range 5.1–10 min) and comparable between men and women (Table 1). An example of a dark adaptation curve from one of the participants is provided in Fig. 1. There was no significant correlation between time to rod intercept or rod adaptation rate and choroidal thickness with the linear regression coefficient for time to rod intercept being 0.072 (CI95−0.21 to 0.37, P = 0.64) min per 100 μm increase in choroidal thickness, adjusted for age and sex (Fig. 2, Table 2). When the choroidal thickness was included as a dichotomous variable (choroidal thickness greater or smaller than the median of 359 μm) the rod intercept was numerically 0.29 min (CI95 0.25–0.30 min) longer in the eyes with the thicker choroids (P = 0.57 adjusted for age and sex) (data not tabulated). There was no significant association between the rod-mediated dark adaptation (time to rod intercept, rod adaptation rate) and age, sex, refractive error, axial length or blood pressure (Table 2). Including refraction, axial length and the blood pressure in the analyses of the correlation of time to rod intercept and choroidal thickness did not alter the results (data not tabulated).Fig. 2

Bottom Line: There was no significant correlation between any of the two measures of rod-mediated dark adaptation and choroidal thickness (time to rod intercept versus choroidal thickness 0.072 (CI95 -0.23 to 0.38) min/100 μm, P = 0.64, adjusted for age and sex).Choroidal thickness, refraction and ocular axial length had no detectable effect on rod-mediated dark adaptation in healthy young subjects.Our results do not support that variations in dark adaptation can be attributed to variations in choroidal thickness.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Zealand University Hospital, Sygehusvej 10, DK-4000, Roskilde, Denmark. icm@dadlnet.dk.

ABSTRACT

Background: Dark adaptation is an energy-requiring process in the outer retina nourished by the profusely perfused choroid. We hypothesized that variations in choroidal thickness might affect the rate of dark adaptation.

Method: Cross-sectional, observational study of 42 healthy university students (mean age 25 ± 2.0 years, 29 % men) who were examined using an abbreviated automated dark adaptometry protocol with a 2° diameter stimulus centered 5° above the point of fixation. The early, linear part of the rod-mediated dark adaptation curve was analyzed to extract the time required to reach a sensitivity of 5.0 × 10(-3) cd/m2 (time to rod intercept) and the slope (rod adaptation rate). The choroid was imaged using enhanced-depth imaging spectral-domain optical coherence tomography (EDI-OCT).

Results: The time to the rod intercept was 7.3 ± 0.94 (range 5.1 - 10.2) min. Choroidal thickness 2.5° above the fovea was 348 ± 104 (range 153-534) μm. There was no significant correlation between any of the two measures of rod-mediated dark adaptation and choroidal thickness (time to rod intercept versus choroidal thickness 0.072 (CI95 -0.23 to 0.38) min/100 μm, P = 0.64, adjusted for age and sex). There was no association between the time-to-rod-intercept or the dark adaptation rate and axial length, refraction, gender or age.

Conclusion: Choroidal thickness, refraction and ocular axial length had no detectable effect on rod-mediated dark adaptation in healthy young subjects. Our results do not support that variations in dark adaptation can be attributed to variations in choroidal thickness.

No MeSH data available.


Related in: MedlinePlus