Choroidal Thickness Changes Following Vitrectomy in Epiretinal Membrane Based on the Optical Coherence Tomography Pattern

Jun Min Park; Myeong In Yeom; Jung Min Park

doi:10.3341/jkos.2018.59.7.637

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Park, Yeom, and Park: Choroidal Thickness Changes Following Vitrectomy in Epiretinal Membrane Based on the Optical Coherence Tomography Pattern

Original Article

J Korean Ophthalmol Soc 2018;59(7):637-649.

Published online: 25 September 2018

DOI: https://doi.org/10.3341/jkos.2018.59.7.637

Choroidal Thickness Changes Following Vitrectomy in Epiretinal Membrane Based on the Optical Coherence Tomography Pattern

Jun Min Park, MD, Myeong In Yeom, MD, Jung Min Park, MD, PhD

Department of Ophthalmology, Maryknoll Medical Center, Busan, Korea

Address reprint requests to Jung Min Park, MD, PhD Department of Ophthalmology, Maryknoll Medical Center, #121 Junggu-ro, Jung-gu, Busan 48972, Korea Tel: 82-51-461-2549, Fax: 82-51-465-7470 E-mail: pjm1438@hanmail.net

Received 22 March 2018 Revised 9 May 2018 Accepted 22 June 2018

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

To analyze the influence of morphological classification in epiretinal membrane (ERM) based on surgical outcomes and optical coherence tomography (OCT) of the postoperative choroidal thickness.

Methods

This observational study included 122 eyes with ERM who underwent vitrectomy. Using OCT, the preoperative ERM was classified into six types: cystoid macular edema (CME), convex, flat, normal foveal contour (Normal), pseudolamellar hole (PLH), and vitreomacular traction (VMT). The preoperative multifocal electroretinogram (mfERG), postoperative change in subfoveal choroidal thickness (SCT), central macular thickness (CMT), and best-corrected visual acuity (BCVA) were compared.

Results

Preoperative subfoveal choroidal thickness increased in the VMT type compared to the fellow eye (207 µm vs. 234 µm, p = 0.028). Choroidal thickness decreased in all types at 12 months after vitrectomy (all, p < 0.05). There was a positive linear correlation between the mfERG and the preoperative BCVA (p = 0.001). The initial visual acuity was best in the Normal type followed by the flat, PLH, convex, CME, and VMT types (p = 0.001). The final visual acuity was the best in the Normal type, followed by the PLH, Flat, VMT, Convex, and CME types (p = 0.030). Gas tamponade during the surgery did not affect the surgical outcomes of the CMT (p = 0.458), BCVA (p = 0.550), and SCT (p = 0.127).

Conclusions

Preoperative SCT increased only in the VMT type, but choroidal thickness decreased in all types after vitrectomy, regardless of the preoperative morphology.

Keywords: Choroidal thickness, Idiopathic epiretinal membrane, Multifocal electroretinogram, Optical coherence tomography, Visual acuity

References

1. Pearlstone AD. The incidence of idiopathic preretinal macular gliosis. Ann Ophthalmol. 1985; 17:378–80.

2. Fraser-Bell S, Guzowski M, Rochtchina E, et al. Five-year abdominal incidence and progression of epiretinal membranes: the Blue Mountains Eye Study. Ophthalmology. 2003; 110:34–40.

3. Meyer CH, Rodrigues EB, Mennel S, et al. Spontaneous separation of epiretinal membrane in young subjects: personal observations and review of the literature. Graefes Arch Clin Exp Ophthalmol. 2004; 242:977–85.

4. Johnson TM, Johnson MW. Epiretinal membrane. Ophthalmology. 2nd ed.St Louis: Mosby;2004. p. 947–50.

5. Wilkins JR, Puliafito CA, Hee MR, et al. Characterization of abdominal membranes using optical coherence tomography. Ophthalmology. 1996; 103:2142–51.

6. Sezer T, Altı nışı k M, Koytak İ A, Özdemir MH. The choroid and optical coherence tomography. Turk J Ophthalmol. 2016; 46:30–7.

7. Stanga PE, Lim JI, Hamilton P. Indocyanine green angiography in chorioretinal diseases: indications and interpretation: an abdominal-based update. Ophthalmology. 2003; 110:15–21. quiz 22–3.

8. Michalewska Z, Michalewski J, Adelman RA, et al. Choroidal abdominal measured with swept source optical coherence tomography abdominal and after vitrectomy with internal limiting membrane peeling for idiopathic epiretinal membranes. Retina. 2015; 35:487–91.

9. Ahn SJ, Woo SJ, Park KH. Choroidal thickness change following vitrectomy in idiopathic epiretinal membrane and macular hole. Graefes Arch Clin Exp Ophthalmol. 2016; 254:1059–67.

10. Casini G, Loiudice P, Lazzeri S, et al. Analysis of choroidal abdominal change after 25-gauge vitrectomy for idiopathic epiretinal membrane with or without phacoemulsification and intraocular lens implantation. Ophthalmologica. 2017; 237:78–84.

11. Kang EC, Lee KH, Koh HJ. Changes in choroidal thickness after vitrectomy for epiretinal membrane combined with vitreomacular traction. Acta Ophthalmol. 2017; 95:e393–8.

12. Kim CH, Kim JI, Cho HY, Kang SW. Correlation between pre-operative OCT pattern and visual improvement in macular abdominal membrane. J Korean Ophthalmol Soc. 2007; 48:75–82.

13. Kinoshita T, Kovacs KD, Wagley S, Arroyo JG. Morphologic abdominals in epiretinal membranes on ocular coherence tomography as a predictive factor for surgical outcome. Retina. 2011; 31:1692–8.

14. Seo SJ, Lee SJ, Park JM. Surgical outcome according to abdominal in epiretinal membrane based on optical coherence abdominal (OCT). J Korean Ophthalmol Soc. 2013; 54:736–44.

15. Smiddy WE, Maguire AM, Green WR, et al. Idiopathic epiretinal membranes. Ultrastructural characteristics and clinicopathologic correlation. Ophthalmology. 1989; 96:811–20. discussion 821.

16. Wei WB, Xu L, Jonas JB, et al. Subfoveal choroidal thickness: the Beijing Eye Study. Ophthalmology. 2013; 120:175–80.

17. Chung SE, Kang SW, Lee JH, Kim YT. Choroidal thickness in abdominal choroidal vasculopathy and exudative age-related macular degeneration. Ophthalmology. 2011; 118:840–5.

18. Koizumi H, Kano M, Yamamoto A, et al. Subfoveal choroidal thickness during aflibercept therapy for neovascular age-related macular degeneration: twelve-month results. Ophthalmology. 2016; 123:617–24.

19. Cho GE, Cho HY, Kim YT. Change in subfoveal choroidal abdominal after argon laser panretinal photocoagulation. Int J Ophthalmol. 2013; 6:505–9.

20. Kofod M, la Cour M. Quantification of retinal tangential abdominal in epiretinal membranes. Ophthalmology. 2012; 119:1886–91.

21. Kozak I, Barteselli G, Sepah YJ, et al. Correlation of vitreomacular traction with foveal thickness, subfoveal choroidal thickness, and vitreomacular/foveal angle. Curr Eye Res. 2017; 42:297–301.

22. Kadonosono K, Itoh N, Nomura E, Ohno S. Perifoveal abdominal in eyes with epiretinal membranes. Br J Ophthalmol. 1999; 83:1329–31.

23. Kinoshita H, Suzuma K, Maki T, et al. Cyclic stretch and abdominal increase retinal succinate: potential mechanisms for ex-acerbation of ocular neovascularization by mechanical stress. Invest Ophthalmol Vis Sci. 2014; 55:4320–6.

24. Campa C. Effect of VEGF and anti-VEGF compounds on retinal pigment epithelium permeability: an in vitro study. Eur J Ophthalmol. 2013; 23:690–6.

25. Holekamp NM, Shui YB, Beebe DC. Vitrectomy surgery increases oxygen exposure to the lens: a possible mechanism for nuclear abdominal formation. Am J Ophthalmol. 2005; 139:302–10.

26. Lim LS, Tan L, Perera S. Retinal vessel oxygen saturation increases after vitrectomy. Invest Ophthalmol Vis Sci. 2014; 55:3851–6.

27. Friberg TR, Lace JW. A comparison of the elastic properties of abdominal choroid and sclera. Exp Eye Res. 1988; 47:429–36.

28. Kondo M, Miyake Y, Horiguchi M, et al. Clinical evaluation of multifocal electroretinogram. Invest Ophthalmol Vis Sci. 1995; 36:2146–50.

29. Arroyo JG, Irvine AR. Retinal distortion and cotton-wool spots abdominal with epiretinal membrane contraction. Ophthalmology. 1995; 102:662–8.

30. Yamamoto T, Hitani K, Tsukahara I, et al. Early postoperative abdominall thickness changes and complications after vitrectomy for abdominal macular edema. Am J Ophthalmol. 2003; 135:14–9.

31. Tan CS, Ouyang Y, Ruiz H, Sadda SR. Diurnal variation of abdominal thickness in normal, healthy subjects measured by spectral abdominal optical coherence tomography. Invest Ophthalmol Vis Sci. 2012; 53:261–6.

32. Yilmaz T, Karci AA, Yilmaz İ, et al. abdominal changes in abdominal choroidal thickness after cataract surgery. Med Sci Monit. 2016; 22:1566–70.

33. Shahzad R, Siddiqui MAR, Zafar S, et al. Choroidal thickness changes following cataract surgery using swept source optical abdominal tomography. Can J Ophthalmol. 2018; 53:60–4.

34. Cobos E, Arias L, Ruiz-Moreno J, et al. Preoperative study of the inner segment/outer segment junction of photoreceptors by spectral-abdominal optical coherence tomography as a prognostic factor in patients with epiretinal membranes. Clin Ophthalmol. 2013; 7:1467–70.

35. Kim MH, Jeon CY, Baek SK, et al. The Thickness of each retinal layer and visual acuity after vitrectomy in idiopathic epiretinal membrane. J Korean Ophthalmol Soc. 2017; 58:420–9.

Figure 1.

The type of epiretinal membrane in optical coherence tomography images. (A) The cystoid macular edema type shows globally adherent membrane and formation of intraretinal cystoid space. (B) The convex type shows globally adherent membrane and dome shaped retina due to diffuse thickening of neurosensory retina. (C) The flat type shows globally adherent membrane and flat foveal contour. (D) The normal type shows normal foveal contour. (E) The pseudolamellar hole type shows steepened foveal fit. (F) The vitreomacular traction type shows focal adherent membrane bridging between vitreous and retina.

Figure 2.

Longitudinal changes of the best corrected visual acuity (BCVA) before and after epiretinal membrane surgery. BCVA significantly increased in all types after surgery. CME = cystoid macular edema type; Convex = convex type; Flat = flat type; Normal = normal foveal contour type; PLH = pseudolamellar hole type; VMT = vitreomacular traction type.

Figure 3.

Scattergram demonstraing the relation between preoperative multifocal electroretinogram (Ring1 amplitude) and best corrected visual acuity (BCVA). (A) Ring1 amplitude is significantly related to the preoperative BCVA (rho = −0.316, R² = 0.126, p = 0.001^*). (B) Ring1 amplitude is not significantly related to the postoperative BCVA (rho = −0.113, R² = 0.022, p = 0.308^*). Regression lines are shown on the scattergram as the red lines. M = months; mfERG = multifocal electroretinogram. ^* Spearman correlation analysis.

Figure 4.

Scattergram demonstraing the relation between the preoperative central macular thickness (CMT) and best corrected visual acuity (BCVA). (A) Preoperative CMT is significantly related to the preoperative BCVA (rho = 0.587, R² = 0.398, p < 0.001^*). (B) Preoperative CMT is significantly related to the BCVA change (at 12 months) (rho = 0.244, R² = 0.061, p = 0.009^*). (C) Preoperative CMT is significantly related to the CMT change (at 12 months) (rho = 0.860, R² = 0.758, p < 0.001^*). M = months. Regression lines are shown on the scattergram as the red lines. ^* Spearman correlation analysis.

Table 1.

Demographic and clinical characteristics of patients

	Total	CME	Convex	Flat	Normal	PLH	VMT	p-value
Number of eyes	122	14	30	37	11	21	9
Gender (female:male)	85:37	12:5	25:9	27:10	8:3	16:5	4:5	0.613^†
Age (years)	67.5 ± 7.3	65.6 ± 9.8	69.9 ± 6.5	65.9 ± 7.1	67.8 ± 5.8	66.4 ± 6.9	71.4±7.2	0.153^*
Phakic:Pseudophakic	89:33	10:4	21:9	24:13	10:1	19:2	5:4	0.252^†
Recurrent of ERM	12	2	3	4	0	1	2	0.590^†
ERM in fellow eye	18	3	4	4	1	4	2
EZ disruption	10	3	2	2	0	1	2	0.620^†

Values are presented as number or mean ± SD unless otherwise indicated.

CME = cystoid macular edema type; Convex = convex type; Flat = flat type; Normal = normal foveal contour type; PLH = pseudolamellar hole type; VMT = vitreomacular traction type; ERM = epiretinal membrane; EZ = ellipsoid zone (photoreceptor inner segment/outer segment).

^* Kruskal-Wallis test

^† Pearson's chi-square test.

Table 2.

logMAR visual acuity and mean BCVA change according to the ERM type

BCVA	CME	Convex	Flat	Normal	PLH	VMT	p-value^†
Preoperative	0.54 ± 0.31	0.53 ± 0.22	0.34 ± 0.18	0.31 ± 0.28	0.41 ± 0.19	0.56 ± 0.27	0.002^*
1 month	0.41 ± 0.29	0.27 ± 0.26	0.16 ± 0.13	0.12 ± 0.14	0.22 ± 0.21	0.26 ± 0.17	0.010^*
2 months	0.30 ± 0.27	0.24 ± 0.22	0.13 ± 0.13	0.06 ± 0.11	0.13 ± 0.12	0.22 ± 0.16	0.009^*
3 months	0.24 ± 0.22	0.21 ± 0.20	0.10 ± 0.10	0.05 ± 0.10	0.11 ± 0.11	0.18 ± 0.17	0.017^*
6 months	0.25 ± 0.23	0.21 ± 0.22	0.11 ± 0.13	0.06 ± 0.10	0.11 ± 0.13	0.16 ± 0.18	0.031^*
12 months	0.19 ± 0.21	0.16 ± 0.19	0.09 ± 0.13	0.02 ± 0.04	0.10 ± 0.08	0.13 ± 0.14	0.030^*
BCVA change (1)	0.13 ± 0.18	0.24 ± 0.26	0.19 ± 0.15	0.19 ± 0.28	0.19 ± 0.21	0.30 ± 0.30
p-value^‡	0.017^*	0.010^*	<0.001^*	0.240	0.003^*	0.020^*
BCVA change (2)	0.24 ± 0.15	0.27 ± 0.23	0.23 ± 0.18	0.25 ± 0.31	0.28 ± 0.15	0.33 ± 0.22
p-value^‡	0.010^*	0.010^*	<0.001^*	0.011^*	<0.001^*	0.010^*
BCVA change (3)	0.31 ± 0.19	0.30 ± 0.24	0.24 ± 0.17	0.25 ± 0.31	0.30 ± 0.18	0.38 ± 0.24
p-value^‡	0.010^*	0.010^*	<0.001^*	0.011^*	<0.001^*	0.011^*
BCVA change (6)	0.31 ± 0.18	0.30 ± 0.24	0.23 ± 0.20	0.25 ± 0.3	0.30 ± 0.19	0.40 ± 0.24
p-value^‡	0.010^*	0.010^*	<0.001^*	0.011^*	<0.001^*	0.012^*
BCVA change (12)	0.36 ± 0.21	0.34 ± 0.24	0.24 ± 0.20	0.29 ± 0.27	0.32 ± 0.18	0.42 ± 0.23
p-value^‡	0.010^*	0.010^*	<0.001^*	0.005^*	<0.001^*	0.012^*
Overall p-value^§	<0.001^*	<0.001^*	<0.001^*	<0.001^*	<0.001^*	<0.001^*

Values are presented as mean ± SD unless otherwise indicated.

BCVA = best corrected visual acuity (logMAR); ERM = epiretinal membrane; CME = cystoid macular edema type; Convex = convex type; Flat = flat type; Normal = normal foveal contour type; PLH = pseudolamellar hole type; VMT = vitreomacular traction type.

^* Indicates statistical significance

^† Kruskal-Wallis test (comparing among the groups)

^‡ Wilcoxon signed rank test (compairing the BCVA before and after surgery)

^§ Friedman test.

Table 3.

Relation among preoperative multifocal ERG results, BCVA and preoperative CMT

Type	ERM eye mfERG Fellow eye mfERG	p-value^†	Preoperative BCVA	Postoperative BCVA (6 months)	Postoperative BCVA (12 months)	) Preoperative CMT (μm)
CME	85.66 ± 29.63 117.50 ± 30.6	0.012	0.54 ± 0.31	0.25 ± 0.23	0.19 ± 0.21	490.0 ± 92.9
Convex	89.08 ± 42.56 142.60 ± 39.75	<0.001	0.53 ± 0.22	0.21 ± 0.22	0.16 ± 0.19	476.0 ± 62.6
Flat	90.98 ± 34.26 107.10 ± 36.08	0.007	0.34 ± 0.18	0.11 ± 0.13	0.09 ± 0.13	374.0 ± 38.9
Normal	111.50 ± 35.55 126.00 ± 41.00	0.028	0.31 ± 0.28	0.06 ± 0.10	0.02 ± 0.04	301.0 ± 37.8
PLH	90.57 ± 35.01 116.20 ± 46.33	0.011	0.41 ± 0.19	0.11 ± 0.13	0.07 ± 0.08	376.0 ± 72.3
VMT	79.34 ± 27.51 109.40 ± 67.25	0.021	0.56 ± 0.27	0.16 ± 0.18	0.13 ± 0.14	444.0 ± 101
p-value	0.038^*,§0.076^§		0.001^*,§	0.733^‡	0.308^‡	0.054^‡

Values are presented as mean ± SD unless otherwise indicated.

ERG = electroretinogram; BCVA = best corrected visual acuity (logMAR); CMT = central macular thickness; ERM = epiretinal membrane; mfERG = multifocal electroretinogram of Ring1 amplitude (nV/deg²); CME = cystoid macular edema type; Convex = convex type; Flat = flat type; Normal = normal foveal contour type; PLH = pseudolamellar hole type; VMT = vitreomacular traction type.

^* Indicates statistical significance

^† Wilcoxon signed rank test (compairing between the eyes affected by ERM and the normal fellow eyes)

^‡ Spearman correlation analysis (linear correlation between mfERG and BCVA or mfERG and CMT)

^§ Kruskal-Wallis test (comparing among the groups).

Table 4.

Preoperative OCT results of SCT

Preoperative SCT	CME (μ m)	Convex (μ m)	Flat (μ m)	Normal (μ m)	PLH (μ m)	VMT (μ m)	Total (μ m)
ERM eye	213.4 ± 73.0	179.2 ± 73.4	186.9 ± 61.6	186.1 ± 68.2	185.6 ± 65.1	234.0 ± 39.8	189.7 ± 63.9
Fellow eye	199.2 ± 47.9	184.3 ± 76.6	193.0 ± 51.1	183.0 ± 70.6	183.4 ± 69.8	207.1 ± 48.4	192.6 ± 68.4
p-value^†	0.162	0.513	0.319	0.504	0.601	0.028^*	0.162
p-value^‡	0.475	1.000	0.718	0.759	0.875	0.043^*	0.249

Values are presented as mean ± SD unless otherwise indicated.

OCT = optical coherence tomography; SCT = subfoveal choroidal thickness; CME = cystoid macular edema type; Convex = convex type; Flat = flat type; Normal = normal foveal contour type; PLH = pseudolamellar hole type; VMT = vitreomacular traction type; ERM = epiretinal membrane.

^* Indicates statistical significance

^† Wilcoxon signed rank test (comparing between the ERM eye and the fellow eye)

^‡ Wilcoxon signed rank test (excluding the cases of ERM patients in the fellow eye).

Table 5.

Subfoveal choroidal thickness (SCT) before and after surgery

SCT	CME (μ m)	Convex (μ m)	Flat (μ m)	Normal (μ m)	PLH (μ m)	VMT (μ m)	Total (μ m)	p-value^‡
Preoperative	213.4 ± 73.0	179.2 ± 73.4	186.9 ± 61.6	186.1 ± 68.2	185.6 ± 65.1	234.0 ± 39.8	191.3 ± 66.6	0.085
1 wk	210.7 ± 69.5	185.1 ± 76.4	189.3 ± 60.9	188.5 ± 67.7	190.7 ± 63.8	224.6 ± 57.0	192.7 ± 67.2	0.149
p-value^†	0.432(+)	0.063(+)	0.037^*(+)	0.032^*(+)	0.079(+)	0.108(+)	0.125(+)
1 month	208.29 ± 70.6	179.6 ± 74.9	186.8 ± 63.9	182.2 ± 57.9	185.7 ± 64.5	219.5 ± 58.2	191.8 ± 67.2	0.434
p-value^†	0.078	0.572	0.011^*	0.285	0.986	0.050^*	0.001^*
3 months	201.1 ± 70.0	170.4 ± 73.2	186.8 ± 60.0	177.4 ± 56.2	182.1 ± 65.3	203.4 ± 63.5	184.1 ± 65.7	0.712
p-value^†	0.008^*	0.024^*	0.001^*	0.012^*	0.053	0.018^*	<0.001^*
6 months	199.0 ± 69.3	170.8 ± 68.3	186.7 ± 59.5	174.3 ± 58.5	182.7 ± 65.1	196.4 ± 58.4	182.7 ± 63.7	0.701
p-value^†	0.002^*	0.013^*	0.015^*	0.007^*	0.067	0.012^*	<0.001^*
12 months	197.2 ± 68.3	170.5 ± 66.4	182.1 ± 62.7	169.5 ± 57.6	179.5 ± 62.5	193.1 ± 53.5	180.1 ± 62.6	0.470
p-value^†	0.002^*	0.024^*	0.004^*	0.022^*	0.048^*	0.008^*	<0.001^*
Overall p-value^§	<0.001^*	<0.001^*	<0.001^*	<0.001^*	<0.001^*	<0.001^*	<0.001^*

Values are presented as mean ± SD unless otherwise indicated. (+) means increased SCT, otherwise means decreased SCT.

CME = cystoid macular edema type; Convex = convex type; Flat = flat type; Normal = normal foveal contour type; PLH = pseudolamellar hole type; VMT = vitreomacular traction type; wk = week.

^* Indicates statistical significance

^† Wilcoxon signed rank test (compairing the SCT before and after surgery)

^‡ Kruskal-Wallis test (comparing among the groups)

^§ Friedman test.

Table 6.

Central subfield macular thickness before and after surgery

CMT	CME (μ m)	Convex (μ m)	Flat (μ m)	Normal (μ m)	PLH (μ m)	VMT (μ m)	p-value^‡
Preoperative	481.9 ± 94.0	475.9 ± 62.6	374.0 ± 38.9	301.7 ± 35.9	376.1 ± 72.3	419.2 ± 101.8	<0.001^*
1 wk	449.7 ± 74.9	437.1 ± 52.1	365.4 ± 42.1	313.3 ± 47.3	372.2 ± 61.1	369.8 ± 69.6	<0.001^*
p-value^†	0.002^*	<0.001^*	0.031^*	0.182(+)	0.498	0.066
1 month	401.2 ± 65.2	411.3 ± 47.2	359.7 ± 39.4	329.6 ± 52.2	354.7 ± 54.8	341.9 ± 64.0	<0.001^*
p-value^†	0.001^*	<0.001^*	0.008^*	0.050(+)^*	0.130	0.021^*
3 months	371.2 ± 40.6	383.1 ± 39.1	343.3 ± 34.9	302.8 ± 42.3	346.1 ± 50.4	330.3 ± 49.9	<0.001^*
p-value^†	0.001^*	<0.001^*	<0.001^*	0.514(+)	0.018^*	0.015^*
6 months	361.9 ± 39.3	371.3 ± 37.8	329.2 ± 37.2	300.2 ± 49.6	337.7 ± 44.5	325.7 ± 41.9	<0.001^*
p-value^†	0.001^*	<0.001^*	<0.001^*	0.213	0.005^*	0.015^*
12 months	358.3 ± 38.1	356.5 ± 37.4	323.7 ± 36.3	291.5 ± 44.4	326.5 ± 45.0	318.0 ± 28.6	<0.001^*
p-value^†	0.001^*	<0.001^*	<0.001^*	0.130	0.001^*	0.008^*
CMT reduction	123.6 ± 81.2	119.5 ± 49.9	50.3 ± 32.9	10.3 ± 35.6	49.1 ± 47.1	101.1 ± 108.4	<0.001^*
Overall p-value^§	<0.001^*	<0.001^*	<0.001^*	<0.001^*	<0.001^*	<0.001^*

Values are presented as mean ± SD unless otherwise indicated. (+) means increased central macular thickness (CMT), otherwise means decreased CMT.

CME = cystoid macular edema type; Convex = convex type; Flat = flat type; Normal = normal foveal contour type; PLH = pseudolamellar hole type; VMT = vitreomacular traction type; wk = week.

^* Indicates statistical significance

^† Wilcoxon signed rank test (compairing the CMT before and after surgery)

^‡ Kruskal-Wallis test (comparing among the groups)

^§ Friedman test.

Table 7.

Effects of 10% SF₆ gas tamponade in convex type

	Preoperative	1 week	1 month	3 months	6 months	1 year
BCVA
Group 1	0.48 ± 0.21	0.38 ± 0.23	0.26 ± 0.27	0.19 ± 0.13	0.20 ± 0.17	0.16 ± 0.13
Group 2	0.58 ± 0.35	0.39 ± 0.08	0.29 ± 0.07	0.22 ± 0.07	0.21 ± 0.14	0.16 ± 0.07
p-value^*	0.919	0.556	0.622	0.639	0.898	0.550
CMT (μ m)
Group 1	468.5 ± 39.4	431.8 ± 41.9	398.6 ± 32.3	385.4 ± 33.8	374.1 ± 29.9	359.9 ± 30.1
Group 2	480.9 ± 74.9	440.6 ± 58.9	419.8 ± 54.1	381.6 ± 43.2	369.5 ± 43.1	354.2 ± 42.4
p-value^*	0.657	0.204	0.398	0.719	0.641	0.458
SCT (μ m)
Group 1	184.1 ± 40.9	193.0 ± 29.4	189.0 ± 38.7	176.4 ± 45.0	175.7 ± 43.3	179.7 ± 43.7
Group 2	192.1 ± 72.5	198.7 ± 81.2	189.9 ± 78.3	178.2 ± 75.9	179.0 ± 67.9	174.2 ± 64.1
p-value^*	0.116	0.792	0.676	0.769	0.461	0.127

Values are presented as number or mean ± SD unless otherwise indicated. ‘Group 1’ means ‘gas tamponade (n = 12)’ and ‘Group 2’ means

‘No gas tamponade (n = 18)’.

BCVA = best corrected visual acuity (logMAR); CMT = central macular thickness; SCT = subfoveal choroidal thickness.

^* Mann Whitney U-test.

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