Background Anterior segment morphometry is crucial for ophthalmologists to understand the visual outcomes of cataract surgery, keratorefractive surgery, as well as some other anterior segment disorders. Previous reports in literature have shown that anterior chamber depth (ACD) may shift slightly after vitrectomy. This study aimed to characterize the short-term changes in ACD in eyes after vitrectomy by means of A-scan ultrasound. Methods A prospective case series study was carried out on 29 eyes of 29 patients who underwent vitrectomy as the sole procedure. ACD was measured using A-scan ultrasound biometry shortly before vitrectomy and 1 week, 1 month, and 3 months after the surgery. Postoperative ACDs were compared with baseline. Results Twenty-nine patients (16 males and 13 females) were enrolled in the study, with mean age of (50 11) (25-65) years. Twenty-three eyes of 23 patients were vitrectomized for vitreous hemorrhage (VH) and the other six were operated for idiopathic epiretinal membrane (ERM). The mean preoperative ACD of the VH eyes was (2.98+/-0.38) mm. No significant difference was found between the ACD of the VH eyes and their fellow eyes (P=0.058). The average preoperative ACD in the ERM eyes was (2.94+/-0.31) mm, which was statistically deeper than that of their fellow eyes ((2.85+/-0.28) mm, P=0.008). No statistical difference was found in the postoperative average ACD of the VH eyes compared with baseline. In the ERM group, the postoperative ACD in the surgical eyes was still statistically deeper than the fellow eyes 1 week after surgery (P=0.034). However, such statistical difference disappeared at 1 or 3 months postoperative (P=0.186 and 0.682). Conclusions ERM may induce deepening of the ACD, which can be recovered by uneventful vitrectomy. VH does not cause shift of ACD, neither does vitrectomy.