Abstract: Objective To investigate the effect of acellular dermal allografts with different orientation as covering material in hydroxyapatite orbital implantation. Design Case control study. Participants Twenty patients (20 eyes) with acellular dermal allografts covering hydroxyapatite orbital implantation in Beijing Tongren Eye Center. Methods The patients were randomly divided into two groups. In the first group （basement outside group）, 10 patients were implanted with acellular dermal matrix with the basement membrane facing outward when covering the hydroxyapatite orbital implantation; in the second group of 10 patients（derma outside group）, the derma surface outward. All patients were followed up for 24 weeks. The clinical evaluation of outcome and complications were compared between the two groups. Main Outcome Measures Clinical evaluation of outcome and complications, including regression time of conjunctival edema, healing of conjunctival wound, shrinkage or not of conjunctival sac and subconjunctival graft of acellular dermal allograft. Results The grafts were well tolerated, with no cases of infection or explanation in the two groups. The regression time of conjunctival edema was 13.1±1.79 days and 12.8±1.93 days in the basement outside group and derma outside group, respectively (t=0.355，P>0.05). There was no obvious narrowing of conjunctival sac found; and all subconjunctival grafts showed white and dense in the two groups. The conjunctival wound healed well, without postoperative complications (including infection, hematoma, incision nonunion, acellular dermal allografts necrosis, orbital implantation exposure, etc.), and no secondary surgery (including debridement, repair and removal) in the two groups. Patients of the two groups were all prothesis 4 weeks after the operation, and the effect was satisfactory. Conclusion Acellular human dermis is an excellent barrier and covering grafting material in hydroxyapatite orbital implantation, and possesses excellent handling properties without needing to distinguish the orientation. (Ophthalmol CHN, 2021, 30: 465-468)

Key words: acellular human dermis, hydroxyapatite orbital implantation