Comparison of therapeutic effects of non-vitrectomy versus vitrectomy for idiopathic epiretinal membrane

Yanan HOU; Qin WANG; Qingshan TIAN; Ailin YOU; Yi WANG

ABSTRACT

Objective:

To compare the efficacy of pars plana vitrectomy (PPV) and nonvitrectomizing vitreous surgery (NVS) in the treatment of idiopathic epimacular membrane (IMEM).

Methods:

A prospective , randomized and comparative clinical study. From April 2019 to May 2020, 21 eyes of 21 patients with IMEM diagnosed in Chongqing Aier Eye Hospital were included in the study. Among them, 11 males had 11 eyes, and 10 females had 10 eyes. Best-corrected visual acuity (BCVA), optical coherence tomography angiography (OCTA), and corneal, intraocular, and global aberration measurements were performed in all eyes. The international standard logarithmic visual acuity chart was used for BCVA examination, and the visual acuity was converted into logarithm of minimum angle of resolution (logMAR) during statistics. The iTrace visual function analyzer was used to measure the corneal, intraocular and whole ocular aberrations, and the dysfunction lens index (DLI) was calculated. Lens density in Scheimpflug images was calculated using Pentacam three-dimensional anterior segment analysis and diagnosis system. The 6 mm×6 mm area of the macular area was scanned by OCTA, which was divided by the software automatically into three concentric circles with the fovea as the center, namely the central area with a diameter of 1 mm, the inner ring area with a diameter of 1-3 mm, The outer ring area of 3-6 mm was used to measure the superficial vessel density (SVD) and superficial perfusion density (SPD) of the entire macular area, the central area, the inner ring area, and the outer ring area. The patients were divided into PPV combined with epimacular membrane (MEM) peeling group (PPV group) and NVS direct peeling MEM group (NVS group) by random number table method, 10 cases with 10 eyes and 11 cases with 11 eyes, respectively. The age of the two groups ( t=-0.72), logMAR BCVA ( t=-0.98), lens density ( t=-1.10), DLI ( t=1.15), SVD ( t=0.82) and SPD ( t=1.19) of entire macular area, corneal aberration ( t=0.45), intraocular aberration ( t=-0.22), and whole eye aberration ( t=0.83), there was no significant difference ( P>0.05). All eyes were operated on with a 27G vitrectomy system. The MEM was removed from the eyes of the NVS group under NVS condition, and the MEM was removed from the eyes of the PPV group under the condition of PPV, and the operation time was recorded at the same time. The follow-up period after surgery was 12 months. Relevant examinations were performed using the same equipment and methods before surgery. Taking the last follow-up as the time point for efficacy judgment, the BCVA, lens opacity, DLI, visual quality, SVD, SPD and MEM recurrence in the macula were compared between the two groups. The two groups were compared by paired t test.

Results:

The operation time of eyes in PPV group and NVS group was 20.81±3.52 and 5.70±1.30 min, respectively, and the difference was statistically significant ( t=7.23, P<0.001). At the last follow-up, the logMAR BCVA of PPV group and NVS group were 0.65±0.25 and 0.44±0.20, respectively, and the difference was statistically significant ( t=-2.16, P=0.04); compared with before operation, the BCVA of eyes of the two groups was significantly improved, and the difference was statistically significant. ( t=2.52, 4.41; P=0.033, P<0.001). The lens density and DLI of the affected eyes in the PPV group and NVS group were 10.64±1.58, 6.24±3.99 and 5.77±1.63, 7.74±1.55, respectively, and the differences were statistically significant ( t=-3.90, 2.85; P<0.05). The macular area SVD ( t=1.03), SPD ( t=1.77), corneal aberration ( t=-0.42), intraocular aberration ( t=-1.10), and whole-eye aberration ( t=-1.17) of eyes of the two groups, the difference was not statistically significant ( P>0.05). During the follow-up period, there were 2 eyes with MEM recurrence, 1 eye in the PPV group and 1 eye in the NVS group; there was no significant difference in the recurrence rate of MEM between the two groups ( χ2=0.005, P=0.94).

Conclusion:

Compared with PPV combined with MEM stripping, the BCVA after NVS surgery increases more, has a better protective effect on the lens, and has a shorter operation time.