Background This study aims to investigate bilateral orbital development differences and influencing factors in retinoblastoma patients undergoing unilateral enucleation.Methods A retrospective comparative analysis was performed on patients from Beijing Tongren Hospital (January 2011-December 2020). Preoperative and 3 months, 1 year, 3 years postoperative, and the final follow-up imaging data were collected, with bilateral orbital volumes reconstructed using ITK-SNAP software.Results Thirty-nine patients were followed for an average of 7.7 +/- 2.45 years. Average orbital volumes (mm3) for the surgical and nonsurgical sides before surgery were 14,323.81 +/- 4596.60 and 14,457.93 +/- 4732.26 (p = 0.330). Postoperative volumes at 3 months were 16,481.84 +/- 4034.21 and 16,866.45 +/- 3999.71 (p = 0.007). At 12 months, volumes were 16,798.16 +/- 3323.33 and 18,119.16 +/- 3840.27 (p = 0.000). At 36 months, volumes were 18,758.26 +/- 2917.35 and 19,973.55 +/- 3189.83 (p = 0.000). The last follow-up volumes were 20,523.78 +/- 3221.20 and 21,576.78 +/- 3381.96 (p = 0.000). Bilateral volume differences were 2.28%, 7.29%, 6.08%, and 4.88% at 3 months, 12 months, 36 months after operation, and final follow-up. The growth trajectory on the surgical side demonstrated growth restrictions, accompanied by a shift in the growth peak. Factors affecting development included the age at the time of operation and the type of orbital implants.Conclusions Volumetric analysis revealed active orbital development between 3 and 12 months post-enucleation, followed by a significant plateau phase. The final orbital volume deficit in the surgical orbit stabilized at approximately 5% compared to the non-operated orbit. Hydrogel implants demonstrated a trade-off: potentially reduced volume deficit but higher complication risks.