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Case series of shrinking hydroxyapatite orbital implants
  1. Louis S Han1,2,
  2. Rodney B Keillor3,
  3. Robert G Weatherhead1
  1. 1 Ophthalmology, Christchurch Hospital, Christchurch, New Zealand
  2. 2 Ophthalmology, Greenlane Clinical Centre, Auckland, New Zealand
  3. 3 Keillor Ophthalmology, Marinoto Clinic, Dunedin, New Zealand
  1. Correspondence to Dr Louis S Han, Ophthalmology, Christchurch Hospital, Christchurch 8011, New Zealand;{at}


Background An orbital implant is used after enucleation or evisceration surgery to replace the volume lost and to aid in prosthesis fitting and movement. Different materials have been used through the years. The authors noted that with bone-derived hydroxyapatite orbital implants, some patients lose their orbital volume.

Methods The operating theatre record was searched to find patients who had their hydroxyapatite orbital implant removed at Dunedin Hospital, New Zealand, between 2011 and 2015. The original implant size and size at removal were noted. Histological results were noted. Medical notes were reviewed.

Results A total of six patients had hydroxyapatite orbital implants removed during this time. Four patients had implants that were smaller than their original sizes. All specimens had fibrovascular infiltration noted, three had chronic inflammatory cells and one had osteoclastic activity.

Conclusions Bone-derived hydroxyapatite orbital implants can reduce in size, and this may occur due to osteoclastic activity. The surgeon must consider this scenario when choosing the type of implant to be used after enucleation or evisceration.

  • cosmesis
  • prosthesis
  • orbit

Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information.

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Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information.

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  • Contributors RK and RW designed the study. All authors acquired, analysed and interpreted the data. LH wrote the draft manuscript, which all authors revised critically for important intellectual content. All authors approved the manuscript for publication.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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