Silicone buckle #506 was successfully used as a material for anophthalmic socket implant. The optimal implant material for the anophthalmic socket should resist infection, provoke minimal or no inflammation, and result in minimal rates of exposure. Silicone buckles have been widely approved for their reliability and suitability in retinal detachment surgery. The long-term stability of this material contributes to its successful use as an anophthalmic socket implant as well as scleral implant for retinal procedures.

Porous polyethylene, acrylic sphere, silicone sphere, hydroxyapatite, polymethyl methacrylate, and bioceramics are widely used materials for anophthalmic implants, for which the extrusion rate is reported. Reports indicate the extrusion rates ranging from 3.7 to 8.3% [6,7,8,9], 0.60–1.0% [10, 11], 0.84–18% [12,13,14], 1.2–6.7% [7, 15,16,17,18], 7.1% [19], and 7.0–9.1% [20,21,22]. In this study, the extrusion rate of the silicone buckle sphere was 6.1%, similar to the rates observed for other materials.

One patient whose ophthalmic implant was extruded was post-enucleation. The rate of exposure is higher after enucleation than after evisceration because the anophthalmic implant is not encased by the sclera [23]. To address this problem, wrapping anophthalmic socket implants with vicryl mesh is reported to lower the exposure risk [24]. Another patient had severe lagophthalmos secondary to facial nerve paralysis, potentially associated with a condition prone to infection that led to corneal perforation and evisceration. This patient also suffered from neurotrophic keratopathy due to trigeminal nerve paralysis. The condition was prone to worsening dry eyes, and the poor ocular surface environment was thought to have caused exposure of the implant and subsequent infection.

The use of multiple silicone buckles increases the volume and diameter of the sphere-formed implants. Considering that the silicone buckle #506 has an oval cross-section with a major axis 5 mm, a minor axis 3 mm and a length of 100 mm, its volume is calculated as 1178 mm³. When this volume is reconfigured into spherical forms, the estimated diameters are 13.1 mm for a single buckle, 16.5 mm for two, 18.9 mm for three, and 20.8 mm for four buckles. However, the actual measured diameter was larger than the predicted value: 18 mm for a single, 20 mm for two, 22 mm for three, and 24 mm for four buckles, likely owing to a gap in forming a spherical shape. Determining the implant diameter by choosing a size 2 mm smaller than the axial length in normal to myopic eyes and reducing it by an additional 1 mm in cases of evisceration or hyperopia, reduces the risk of clinically and aesthetically unacceptable superior sulcus deformity and enophthalmos in 85% of patients [25]. Therefore, it is possible that the number of inserted silicone buckles can be determined according to the axial length.

Our analysis revealed a trend of improving mean aesthetic scores with an increasing number of silicone buckles (0.97 without implant, 0.78 with one buckle, 0.68 with two, and 0.42 with three/four buckles). However, these differences did not reach statistical significance (p = 0.123). This lack of statistical significance may be due to several unmeasured patient characteristics. For example, pre-existing orbital anatomy, such as naturally deep-set eyes, could mask the effect of the implant by reducing the perceived asymmetry, even without an implant. Other factors, such as eyelid position and periorbital soft tissue volume, might also influence the aesthetic outcome. To address these limitations in future studies, more objective assessment methods, such as image analysis techniques to quantify sunken areas (e.g., pixel brightness measurements) [26], could be employed. Furthermore, incorporating patients’ subjective assessments of aesthetic outcomes alongside objective evaluations would provide a more comprehensive understanding of the postoperative results [27,28,29].

This study had several limitations. First, this was a retrospective study with a limited sample size. Larger prospective studies are warranted in the future. Second, the follow-up period was relatively short, with 3 months as the shortest period. A longer follow-up is required to confirm the risk of late complications. Third, there were missing data owing to the retrospective nature of the study, which may have affected the accuracy of the exposure rate. While patients lost to follow-up likely represent uncomplicated cases, the possibility of unreported complications treated elsewhere cannot be excluded.

In summary, our findings suggest that the use of silicone buckles as socket implants is safe and may be a valid option. However, future studies are needed to determine complications and long-term outcomes. Further research with larger sample sizes is needed to determine whether adjusting the number of silicone buckles indeed leads to optimal aesthetic results.