Table 1 Comparison of baseline characteristics between subjects stratified by age and axial length

Age (years)

28.1 ± 6.2

46.5 ± 4.5

 < 0.001

34.0 ± 10.5

34.2 ± 10.4

0.926

34.1 ± 10.4

Gender (male; n)

73 (47.4%)

28 (37.3%)

0.150

33 (34.4%)

68 (51.1%)

0.012

101 (44.1%)

Ethnicity (n)

 • Chinese

147 (95.5%)

73 (97.3%)

1.000

91 (94.8%)

129 (97.0%)

0.760

220 (96.1%)

 • Malay

3 (1.9%)

1 (1.3%)

2 (2.1%)

2 (1.5%)

4 (1.7%)

 • Indian

4 (2.6%)

1 (1.3%)

3 (3.1%)

2 (1.5%)

5 (2.2%)

Ocular characteristics

Age < 40 years

( n  = 308)

Age ≥ 40 years

( n  = 148)

P value ^†

Axial length < 26 mm

( n  = 188)

Axial length ≥ 26 mm

( n  = 268)

P value ^†

Total

( n  = 456)

Ocular parameters

Visual acuity (LogMAR)

0.02 ± 0.02

0.03 ± 0.05

0.021

0.01 ± 0.02

0.03 ± 0.04

 < 0.001

0.02 ± 0.03

Axial length (mm)

26.4 ± 1.4

26.4 ± 1.4

0.992

25.1 ± 0.6

27.3 ± 1.1

 < 0.001

26.4 ± 1.4

Spherical equivalent (D)

 − 6.2 ± 2.9

 − 5.4 ± 3.8

0.015

 − 4.4 ± 1.7

 − 7.0 ± 3.6

 < 0.001

 − 5.9 ± 3.3

Choroidal thickness (μm)

 • Triton DRI-OCT

222.5 ± 79.9

205.3 ± 87.2

0.038

255.3 ± 82.0

190.1 ± 71.9

 < 0.001

216.9 ± 82.7

 • PLEX Elite 9000

245.9 ± 82.5

225.6 ± 86.5

0.016

278.7 ± 83.6

211.6 ± 73.1

 < 0.001

239.3 ± 84.3

Optic disc

Peripapillary atrophy (n)

 • None

21 (6.8%)

7 (4.7%)

0.012

21 (11.2%)

7 (2.6%)

 < 0.001

28 (6.1%)

 • Mild

176 (57.1%)

74 (50.0%)

117 (62.2%)

133 (49.6%)

250 (54.8%)

 • Moderate

110 (35.7%)

61 (41.2%)

50 (26.6%)

121 (45.1%)

171 (37.5%)

 • Severe

1 (0.3%)

6 (4.1%)

0

7 (2.6%)

7 (1.5%)

Disc tilt (n)

 • None

35 (11.4%)

11 (7.4%)

0.419

34 (18.1%)

12 (4.5%)

 < 0.001

46 (10.1%)

 • Mild

237 (76.9%)

117 (79.1%)

142 (75.5%)

212 (79.1%)

354 (77.6%)

 • Moderate

34 (11.0%)

20 (13.5%)

12 (6.4%)

42 (15.7%)

54 (11.8%)

 • Severe

2 (0.6%)

0

0

2 (0.7%)

2 (0.4%)

Macula

Myopic macular degeneration (n)

 • None

73 (23.7%)

23 (15.5%)

0.049

68 (36.2%)

28 (10.4%)

 < 0.001

96 (21.1%)

 • Tessellated Fundus

218 (70.8%)

111 (75.0%)

118 (62.8%)

211 (78.7%)

329 (72.1%)

 • Diffuse peripapillary/ chorioretinal atrophy

17 (5.5%)

13 (8.8%)

2 (1.1%)

28 (10.4%)

30 (6.6%)

 • Patchy chorioretinal atrophy

0

1 (0.7%)

0

1 (0.4%)

1 (0.2%)

 • Macular atrophy

0

0

0

0

0

Plus lesions (n)

0

1 (0.7%)

0.325

0

1 (0.4%)

1.000

1 (0.2%)

Macular hole (n)

0

1 (0.7%)

0.325

0

1 (0.4%)

1.000

1 (0.2%)

Myopic tractional maculopathy (n)

0

0

-

0

0

-

0

Retina

Peripheral retina degeneration (n)

 • None

285 (92.5%)

148 (100.0%)

0.002

180 (95.7%)

253 (94.4%)

0.427

433 (95.0%)

 • White without pressure

12 (3.9%)

0

3 (1.6%)

9 (3.4%)

12 (2.6%)

 • Lattice degeneration

10 (3.2%)

0

4 (2.1%)

6 (2.2%)

10 (2.2%)

 • Retinal holes and tears

1 (0.3%)

0

1 (0.5%)

0

1 (0.2%)

 • Retinal detachment

0

0

0

0

0

Retinoschisis (n)

0

3 (2.0%)

0.034

0

3 (1.1%)

0.271

3 (0.7%)

Posterior staphyloma (n)

4 (1.3%)

8 (5.4%)

0.023

0

12 (4.5%)

0.002

12 (2.6%)

Epiretinal membrane (n)

2 (0.6%)

6 (4.1%)

0.016

2 (1.1%)

6 (2.2%)

0.480

8 (1.8%)

Dome shaped macula (n)

0

7 (4.7%)

 < 0.001

0

7 (2.6%)

0.045

7 (1.5%)

Intrachoroidal cavitation (n)

0

3 (2.0%)

0.034

2 (1.1%)

1 (0.4%)

0.572

3 (0.7%)