A simple algorithm for selection of implant size for enucleation and evisceration: a prospective study

Area of Science:

• Ophthalmology
• Ophthalmic Surgery
• Orbital Implantology

Background:

• Enucleation and evisceration are common procedures for eye loss.
• Accurate orbital implant sizing is crucial for optimal aesthetic and functional outcomes.
• Existing methods for implant selection can be imprecise, leading to complications.

Purpose of the Study:

• To evaluate a simple formula for selecting orbital implant size in patients undergoing enucleation, evisceration, and secondary implantation.
• To assess the formula's efficacy using clinical outcomes: superior sulcus deformity, enophthalmos, and prosthesis volume.

Main Methods:

• A prospective study involving 54 patients undergoing primary or secondary implant surgery.
• Orbital implants were sized using the formula: axial length - 2 mm = implant diameter (with modifications for evisceration and hyperopia).
• Measurements included eye volume, implant volume, prosthesis volume, and total volume replacement; clinical outcomes were assessed.

Main Results:

• The formula achieved an average volume replacement of 101%.
• Average prosthetic volume was 2.1 mL, with an average superior sulcus deformity grade of 0.6 and enophthalmos of 1.2 mm.
• Clinically acceptable outcomes were achieved in 85% of patients.

Conclusions:

• The formula effectively enables 100% volume replacement and accommodates a prosthesis of 1.5-2.5 mL.
• It successfully eliminates unacceptable superior sulcus deformity and enophthalmos in the majority of patients.
• A subgroup (15%) with specific histories (infection, radiation, buphthalmos, fractures) experienced residual deformity and enophthalmos, warranting further investigation.