. 2021 Aug 6;9(15):e14977. doi: 10.14814/phy2.14977

TABLE 2.

Ocular measures before, during, and after HDTBR

		BDC−6 seated	BDC−6 supine	HDT2	HDT15	HDT31	HDT45	HDT58	R+6 supine	R+11 supine
TRT (µm)	Control	409.2 392.4–426.0	408.1 391.0–425.2	419.5*** 400.5–438.5	429.2*** 408.8–449.6	435.0*** 416.4–453.7	439.1*** 420.0–458.2	445.1*** 424.9–465.3	435.6*** 417.8–453.3	436.2*** 419.8–452.6
cAG	400.3 381.7–418.9	400.6 381.6–419.5	410.2** 388.3–432.0	419.3* 392.4–446.1	423.7* 395.8–451.7	432.1* 398.2–465.9	436.8* 401.5–472.1	432.4* 400.2–464.6	432.9** 402.2–463.5
iAG	403.3 388.8–417.8	402.3 388.2–416.4	413.1*** 398.6–427.5	420.0** 404.3–435.8	424.8** 408.7–441.0	427.5** 409.7–445.3	430.9*** 412.5–449.2	425.3*** 409.1–441.5	425.0*** 410.4–439.6
RNFL Thickness (µm)	Control	103.1 95.4–110.8	103.0 95.2–110.8	103.2 94.8–111.5	104.0 96.0–112.0	103.7 95.6–111.8	104.6* 96.7–112.4	105.8*** 97.9–113.6	105.7*** 97.9–113.5	106.3*** 98.3–114.2
cAG	100.4 93.4–107.5	99.9 92.8–106.9	100.0 92.9–107.1	100.3 93.0–107.5	101.1 93.5–108.6	101.7 93.7–109.7	102.3 94.2–110.4	103.4* 95.7–111.2	103.5* 95.8–111.2
iAG	101.2 95.6–106.8	101.0 95.4–106.5	100.8 95.4–106.2	101.2 96.0–106.3	101.4 96.5–106.3	101.8 96.6–107.0	102.2 97.3–107.1	103.0* 98.0–108.0	102.7** 97.8–107.7
Choroidal Thickness (µm)	Control	235.9 204.9–267.0	239.9 208.2–271.6	240.2 209.3–271.1	239.3 208.3–270.3	242.3 209.7–274.9	241.6 207.8–275.3	242.5 210.0–275.0	225.9 194.5–257.2	222.3* 188.5–256.0
cAG	209.3 181.6––237.0	212.4 182.8–241.9	210.9 180.9–240.9	214.3 183.6–245.0	212.5 181.6–243.3	209.2 179.2–239.3	209.6 179.7–239.4	205.4 176.4–234.5	204.8 176.0–233.6
iAG	239.6 208.1–271.1	244.1*** 212.1–276.1	241.7 207.1–276.3	244.4 210.0–278.8	241.9 202.1–281.7	239.2 201.2–277.2	240.0 202.1–277.8	227.9 190.7–265.0	223.6** 187.4–259.8
IOP (mmHg)	Control	13.6 12.2–15.1	15.5 13.9–17.1	16.2** 15.2–17.3	15.3 14.5–16.1	14.9 14.1–15.7	15.2* 13.8–16.7	17.0*** 15.2–18.9	15.4 14.0–16.7	15.3 14.6–16.0
cAG	14.7 13.2–16.2	15.8 14.1–17.5	16.8*** 15.6–17.9	16.3 15.2–17.4	16.5†† 16.0–17.0	15.9 14.5–17.2	16.9** 16.0–17.7	16.2 15.1–17.4	16.8*** 15.5–18.1
iAG	14.4 13.9–14.8	16.4*** 15.5–17.2	16.2 14.5–17.9	15.4* 14.4–16.5	16.0** 15.0–17.1	16.7*** 15.7–17.7	15.7 14.2–17.1	16.9*** 15.6–18.1	15.7*** 15.1–16.2

BDC−6

seated

BDC−6

supine

HDT2

HDT15

HDT31

HDT45

HDT58

R+6

supine

R+11

supine

TRT (µm)

Control

409.2

392.4–426.0

408.1

391.0–425.2

419.5***

400.5–438.5

429.2***

408.8–449.6

435.0***

416.4–453.7

439.1***

420.0–458.2

445.1***

424.9–465.3

435.6***

417.8–453.3

436.2***

419.8–452.6

cAG

400.3

381.7–418.9

400.6

381.6–419.5

410.2**

388.3–432.0

419.3*

392.4–446.1

423.7*

395.8–451.7

432.1*

398.2–465.9

436.8*

401.5–472.1

432.4*

400.2–464.6

432.9**

402.2–463.5

iAG

403.3

388.8–417.8

402.3

388.2–416.4

413.1***

398.6–427.5

420.0**

404.3–435.8

424.8**

408.7–441.0

427.5**

409.7–445.3

430.9***

412.5–449.2

425.3***

409.1–441.5

425.0***

410.4–439.6

RNFL Thickness (µm)

Control

103.1

95.4–110.8

103.0

95.2–110.8

103.2

94.8–111.5

104.0

96.0–112.0

103.7

95.6–111.8

104.6*

96.7–112.4

105.8***

97.9–113.6

105.7***

97.9–113.5

106.3***

98.3–114.2

cAG

100.4

93.4–107.5

99.9

92.8–106.9

100.0

92.9–107.1

100.3

93.0–107.5

101.1

93.5–108.6

101.7

93.7–109.7

102.3

94.2–110.4

103.4*

95.7–111.2

103.5*

95.8–111.2

iAG

101.2

95.6–106.8

101.0

95.4–106.5

100.8

95.4–106.2

101.2

96.0–106.3

101.4

96.5–106.3

101.8

96.6–107.0

102.2

97.3–107.1

103.0*

98.0–108.0

102.7**

97.8–107.7

Choroidal Thickness (µm)

Control

235.9

204.9–267.0

239.9

208.2–271.6

240.2

209.3–271.1

239.3

208.3–270.3

242.3

209.7–274.9

241.6

207.8–275.3

242.5

210.0–275.0

225.9

194.5–257.2

222.3*

188.5–256.0

cAG

209.3

181.6––237.0

212.4

182.8–241.9

210.9

180.9–240.9

214.3

183.6–245.0

212.5

181.6–243.3

209.2

179.2–239.3

209.6

179.7–239.4

205.4

176.4–234.5

204.8

176.0–233.6

iAG

239.6

208.1–271.1

244.1***

212.1–276.1

241.7

207.1–276.3

244.4

210.0–278.8

241.9

202.1–281.7

239.2

201.2–277.2

240.0

202.1–277.8

227.9

190.7–265.0

223.6**

187.4–259.8

IOP (mmHg)

Control

13.6

12.2–15.1

15.5

13.9–17.1

16.2**

15.2–17.3

15.3

14.5–16.1

14.9

14.1–15.7

15.2*

13.8–16.7

17.0***

15.2–18.9

15.4

14.0–16.7

15.3

14.6–16.0

cAG

14.7

13.2–16.2

15.8

14.1–17.5

16.8***

15.6–17.9

16.3

15.2–17.4

16.5††

16.0–17.0

15.9

14.5–17.2

16.9**

16.0–17.7

16.2

15.1–17.4

16.8***

15.5–18.1

iAG

14.4

13.9–14.8

16.4***

15.5–17.2

16.2

14.5–17.9

15.4*

14.4–16.5

16.0**

15.0–17.1

16.7***

15.7–17.7

15.7

14.2–17.1

16.9***

15.6–18.1

15.7***

15.1–16.2

Values represent the mean and 95% CI (italics). Significant difference in comparison to BDC‐6 seated: *p < 0.05, **p < 0.01, ***p < 0.001. Significant difference in comparison to the control group: ††p < 0.01.

Abbreviations: AG, continuous artificial gravity; BDC, baseline data collection; HDT, head‐down tilt; iAG, intermittent artificial gravity; IOP, intraocular pressure; R+, recovery day; RNFL, retinal nerve fiber layer; TRT, total retinal thickness.