ObjectiveTo observe the effect of epinephrine in intraocular irrigation solution on retinal vascular caliber and macular thickness. MethodsA prospective control study. 32 eyes of 32 patients with macular hole who underwent vitrectomy were enrolled in this study. The patients including 14 males (14 eyes) and 27 females (18 eyes), with the average age of (64.0±4.5)years. Uncorrected visual acuity, corrected visual acuity, slit lamp biomicroscopy, indirect ophthalmoscopy, fundus color photography and optical coherence tomography were performed in all patients. Retinal vascular caliber located in 0.5-1.0 disc diameter from optic disk was measured from digital fundus photographs and summarized as central retinal artery (CRAE) and vein (CRVE) equivalents in all eyes at baseline and at the 1 month, 3 months follow-up visit. The macular thickness is the distance from retinal interface of inner plexiform layer to retinal pigment epithelium layer. The macula was divided into inner ring ( < 3 mm) and outer ring (3-6 mm) according to the distance from the fovea. The patients were divided into experiment group (include epinephrine in intraocular irrigation solution, 1:1000) and control group (without epinephrine in intraocular irrigation solution), 16 eyes in each group. The difference of CRAE and CRVE between two groups was not significant (P > 0.05). The difference of macular thickness between inner ring and outer ring was not significant (P > 0.05). The average follow-up was 3.5 months. CRAE, CRVE and macular thickness in inner ring and outer ring before and 1 month, 3 months after surgery were comparatively analyzed. ResultsThe differences of CRAE and CRVE before and 1, 3 months after surgery both in experiment group (tCRAE=0.322, 0.148; tCRVE=0.317, 0.005) and control group (tCRAE=0.226, 0.137; tCRVE=0.284, 0.151) were not significant (P > 0.05). The differences of CRAE (t=0.624, 0.424) and CRVE (t=0.015, 0.041) between experiment group and control group also were not significant (P > 0.05). The differences of macular thickness in inner ring and outer ring before and 1, 3 months after surgery both in experiment group (tinner=0.322, 0.148;touter=0.317, 0.005) and control group (tinner=0.226, 0.137;touter=0.284, 0.151) were not significant (P > 0.05). The differences of macular thickness in inner ring (t=1.568, 0.373) and outer ring (t=-1.697, 0.536) between experiment group and control group also were not significant (P > 0.05). ConclusionEpinephrine (1:1000) in intraocular irrigation solution has no effect on retinal vascular caliber and macular thickness in patients with macular hole.