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Vitrectomy and ILM peeling in rhesus macaque: pitfalls and tips for success



The non-human primate (NHP) model is ideal for pre-clinical testing of novel therapies for human retinal diseases due to its similarity to the human visual system. However, intra-ocular delivery of gene therapy or cell transplantation to the retina gets hampered by the sticky vitreous body and poorly permeable inner limiting membrane (ILM) in primates. Although vitrectomy and ILM peeling are commonly performed in patients, many pitfalls exist in carrying out these procedures in the rhesus macaque, which have not been reported previously.


We summarised common surgical pitfalls after performing vitrectomy and ILM peeling in four eyes of two rhesus macaques (one male and one female). We provided corresponding hands-on technical tips based on our surgical experience and literature search. Orbital CT scans were compared between adult rhesus macaques and humans. High-resolution surgical videos were recorded to demonstrate each critical surgical step.


Due to size difference, poor post-operative compliance, and high-standard requirements of a controlled experiment, there were eleven common surgical pitfalls during vitrectomy and ILM peeling in rhesus macaque. Falling into these pitfalls may produce discomfort, add fatigue, cause surgical complications, or even lead to the exclusion of the NHP from an experimental group.


Recognition and circumvention of these pitfalls during vitrectomy and ILM peeling in NHP are essential. By focusing on these surgical pitfalls, we can better carry out preclinical tests of novel therapies for retinal diseases in the NHP model.

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Fig. 1: Pitfalls and tips 1–5.
Fig. 2: Small palpebral fissure in the rhesus macaque.
Fig. 3: Scheme of PVD under microscopic surgical view.
Fig. 4: Scheme of ILM peeling under microscopic surgical view.
Fig. 5: Retinal photography and OCT images after surgery.

Data availability

Data available within the article or its supplementary materials.


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The sponsor or funding organisation had no role in the design or conduct of this research. We thank MJEditor ( for language editing.


National Key R&D Program of China [2021YFA1101200]. National Key R&D Program of China [2016YFC1101200]. National Natural Science Foundation of China [81770926;81800842]. Key R&D Program of Zhejiang Province [2019C03009; 2021C03065]. Key R&D Program of Wenzhou Eye Hospital [YNZD1201902]. National Key R&D Program of China [2019YFC0119300].

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Authors and Affiliations



Conceptualisation: YZ, QP; Data curation: YZ, SL, ML; Formal Analysis: SL, ML, HP, LW, YM; Funding acquisition: YZ, WW; Methodology: YZ, QP; Visualisation: YZ, QP, SL, ML. Writing – original draft: YZ, QP, SL, ML; Writing – review & editing: YZ, QP, WW.

Corresponding authors

Correspondence to Wencan Wu or Yikui Zhang.

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The authors declare no competing interests.

Ethics approval

The research followed the principles of the Declaration of Helsinki, and was approved by the ethics committees of Wenzhou Eye Hospital, Wenzhou Medical University (Ethics ID number: KYK (2017) 53). Patient consents from three male adults were obtained before analysis of their orbital CT scan data in this study.

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Pan, Q., Lu, S., Li, M. et al. Vitrectomy and ILM peeling in rhesus macaque: pitfalls and tips for success. Eye (2022).

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