Assessment of Choroidal Thickness and Volume during the Water Drinking Test by Swept-Source Optical Coherence Tomography

Abstract

Objective To evaluate changes in peripapillary and macular choroidal thickness and volume after the water-drinking test (WDT) using swept-source optical coherence tomography (SS-OCT). Design Prospective, cross-sectional observational study. Participants Fifty-six eyes of 28 healthy volunteers. Methods Participants underwent a 3-dimensional optic disc and macula scanning protocol with a prototype SS-OCT (Topcon Inc., Tokyo, Japan) at baseline and 15, 30, 45, and 120 minutes after the start of the WDT. The WDT consisted of drinking 1000mL of water within five minutes. Objective measurements of the choroid were obtained with automated segmentation of the choroidal boundaries. Main Outcome Measures Choroidal thickness and volume. Results Mean (standard deviation) age of participants was 35.6 ± 9.1 years. Intraocular pressure (IOP) increased from 14.9 ± 2.7 mmHg at baseline to a peak of 16.8 ± 3.0 mmHg at 15 minutes after the WDT (p<0.001). Mean baseline choroidal thickness and volume were 181.3 ± 50.8 μm and 6.19 ± 1.80 mm3 at the optic disc and 217.4 ± 43.6 μm and 7.83 ± 1.55 mm3 at the macula. Following the WDT, peripapillary and macular choroidal thickness increased by a maximum of 5.7% (P < 0.001) and 4.3% (P < 0.001) respectively. Choroidal volumes increased by 6.4% (P < 0.001) and 3.9% (P < 0.001), respectively. There was no association between change in IOP and peripapillary (P = 0.27) or macular (P = 0.09) choroidal thickness. Conclusions Using automated segmentation of SS-OCT measurements, significant increases in choroidal thickness and volume are observed after the WDT in healthy subjects.

The Relationship Between Choroidal Expansion and Intraocular Pressure Rise During the Water Drinking Test in Healthy Subjects and Patients With Exfoliation Syndrome

“…20 In contrast with the results of the study by Mwanza and colleagues, the study by Cennamo et al 23 In the present study, the mean IOP after water ingestion at 30-and 60-minute time-points were higher when compared with their respective baseline levels in both XFS subjects and controls. This finding is also in agreement with the findings of Mansouri et al, 7 in which IOP elevation was observed after water ingestion in healthy volunteers. In their study, peak IOP was attained 15 minutes after water intake, an earlier time-point compared with our findings.…”

“…The magnitude of IOP rise was greater in eyes with XFS compared with controls at only the 60-minute time-point suggesting the possibility of slight impairment of aqueous outflow facility in eyes with XFS. In contrast, we were unable to find a significant association between an increase in ChT and IOP, similar to the findings of Mansouri et al 7 On the basis of our results and those of Mansouri et al, 7 ChT does not seem to be the primary physiological mechanism for IOP increase after water ingestion.…”

The Relationship Between Choroidal Expansion and Intraocular Pressure Rise During the Water Drinking Test in Healthy Subjects and Patients With Exfoliation Syndrome

“…20 In contrast with the results of the study by Mwanza and colleagues, the study by Cennamo et al 23 In the present study, the mean IOP after water ingestion at 30-and 60-minute time-points were higher when compared with their respective baseline levels in both XFS subjects and controls. This finding is also in agreement with the findings of Mansouri et al, 7 in which IOP elevation was observed after water ingestion in healthy volunteers. In their study, peak IOP was attained 15 minutes after water intake, an earlier time-point compared with our findings.…”

“…The magnitude of IOP rise was greater in eyes with XFS compared with controls at only the 60-minute time-point suggesting the possibility of slight impairment of aqueous outflow facility in eyes with XFS. In contrast, we were unable to find a significant association between an increase in ChT and IOP, similar to the findings of Mansouri et al 7 On the basis of our results and those of Mansouri et al, 7 ChT does not seem to be the primary physiological mechanism for IOP increase after water ingestion.…”

In vivo quantification of human aqueous veins by enhanced depth imaging optical coherence tomography and optical coherence tomography angiography images

“…After the water-drinking test, the IOP increased, reaching a peak 15min after water loading, and it then gradually decreased and returned to the normal level 60min after water loading, which was consistent with earlier results [19][20][21] . Our results showed that the area of the aqueous vein decreased after the water-drinking test, reaching its nadir 15min after water loading, followed by a gradual increase to a normal level at 60min.…”

The Effect of the Water Drinking Test on Ocular Parameters and Choroidal Thickness in Glaucoma Suspects

“…A recent study by Mansouri et al [10] in healthy subjects evaluated the changes in choroidal thickness (ChT) following the WDT with the use of the SS-OCT and an automated segmentation software and was in accordance with our results. Although there was a statistically significant increase in the thickness of the choroid, this was not correlated with the rise in IOP.…”

The Relationship Between Choroidal Expansion and Intraocular Pressure Rise During the Water Drinking Test in Healthy Subjects and Patients With Exfoliation Syndrome

“…20 In contrast with the results of the study by Mwanza and colleagues, the study by Cennamo et al 23 In the present study, the mean IOP after water ingestion at 30-and 60-minute time-points were higher when compared with their respective baseline levels in both XFS subjects and controls. This finding is also in agreement with the findings of Mansouri et al, 7 in which IOP elevation was observed after water ingestion in healthy volunteers. In their study, peak IOP was attained 15 minutes after water intake, an earlier time-point compared with our findings.…”

“…The magnitude of IOP rise was greater in eyes with XFS compared with controls at only the 60-minute time-point suggesting the possibility of slight impairment of aqueous outflow facility in eyes with XFS. In contrast, we were unable to find a significant association between an increase in ChT and IOP, similar to the findings of Mansouri et al 7 On the basis of our results and those of Mansouri et al, 7 ChT does not seem to be the primary physiological mechanism for IOP increase after water ingestion.…”

In vivo quantification of human aqueous veins by enhanced depth imaging optical coherence tomography and optical coherence tomography angiography images

“…After the water-drinking test, the IOP increased, reaching a peak 15min after water loading, and it then gradually decreased and returned to the normal level 60min after water loading, which was consistent with earlier results [19][20][21] . Our results showed that the area of the aqueous vein decreased after the water-drinking test, reaching its nadir 15min after water loading, followed by a gradual increase to a normal level at 60min.…”

The Effect of the Water Drinking Test on Ocular Parameters and Choroidal Thickness in Glaucoma Suspects

“…A recent study by Mansouri et al [10] in healthy subjects evaluated the changes in choroidal thickness (ChT) following the WDT with the use of the SS-OCT and an automated segmentation software and was in accordance with our results. Although there was a statistically significant increase in the thickness of the choroid, this was not correlated with the rise in IOP.…”

The Relationship Between Choroidal Expansion and Intraocular Pressure Rise During the Water Drinking Test in Healthy Subjects and Patients With Exfoliation Syndrome

“…20 In contrast with the results of the study by Mwanza and colleagues, the study by Cennamo et al 23 In the present study, the mean IOP after water ingestion at 30-and 60-minute time-points were higher when compared with their respective baseline levels in both XFS subjects and controls. This finding is also in agreement with the findings of Mansouri et al, 7 in which IOP elevation was observed after water ingestion in healthy volunteers. In their study, peak IOP was attained 15 minutes after water intake, an earlier time-point compared with our findings.…”

“…The magnitude of IOP rise was greater in eyes with XFS compared with controls at only the 60-minute time-point suggesting the possibility of slight impairment of aqueous outflow facility in eyes with XFS. In contrast, we were unable to find a significant association between an increase in ChT and IOP, similar to the findings of Mansouri et al 7 On the basis of our results and those of Mansouri et al, 7 ChT does not seem to be the primary physiological mechanism for IOP increase after water ingestion.…”

In vivo quantification of human aqueous veins by enhanced depth imaging optical coherence tomography and optical coherence tomography angiography images

“…After the water-drinking test, the IOP increased, reaching a peak 15min after water loading, and it then gradually decreased and returned to the normal level 60min after water loading, which was consistent with earlier results [19][20][21] . Our results showed that the area of the aqueous vein decreased after the water-drinking test, reaching its nadir 15min after water loading, followed by a gradual increase to a normal level at 60min.…”

The Effect of the Water Drinking Test on Ocular Parameters and Choroidal Thickness in Glaucoma Suspects

“…A recent study by Mansouri et al [10] in healthy subjects evaluated the changes in choroidal thickness (ChT) following the WDT with the use of the SS-OCT and an automated segmentation software and was in accordance with our results. Although there was a statistically significant increase in the thickness of the choroid, this was not correlated with the rise in IOP.…”