In the absence of large trials, it is important for us to discuss whether a well-conducted meta-analysis of smaller randomized controlled trial (RCT) can replace large trials or not. We have evaluated the quality of original literature and methodological quality. The difference between meta-analysis of smaller RCT and the largest randomized trials have also discussed.
Persistent fetal vasculature syndrome (PFVS) is a rare congenital vitreous dysplasia, which is classified as anterior, posterior and combined types according to the location of the vascular abnormalities. The clinical manifestations of PFVS are diverse, and early surgical intervention is very important. The main objective of surgical treatment is to remove the anterior and posterior traction between fibrovascular membranes and retina as well as lens, and to reconstruct clear visual axis. Surgical treatments include pupilloplasty, lensectomy with or without intraocular lens implantation and vitrectomy via limbal or scleral approach. For new technologies, the applications of ophthalmic viscosurgical device and femtosecond lasers have desirable results . In addition to focusing on improving the success rate of surgery, it is also necessary to systematically and comprehensively assess the overall preoperative condition and postoperative visual function of the patients. PFVS eyes have limited improvement in postoperative vision, which is related to the extent of lesion involvement and the occurrence of complications. Eyes with macular dysplasia and tractional retinal detachment, as well as elongated ciliary process, have a poor prognosis of vision after surgery. How to improve postoperative vision in the eye affecting the posterior segment of the eye with PFVS from the microscopic anatomical relationship between the fibrous vascular pedicle and the retina is worth further study. On the other hand, reducing surgical trauma and optimizing surgical procedures in order to improve postoperative visual acuity and reduce postoperative complications are also the key research directions of future PFVS treatments.