Objective. To validate the model for calculating the target upper eyelid height in surgical correction of moderate and severe ptosis.

Material and methods. The main anatomical and functional parameters influencing the outcome of surgical intervention were analyzed (ptosis, eyelid mobility when fixed to the eyebrow and activity of the frontal muscle).

Results. Considering anatomical and functional parameters, the authors proposed a mathematical formula for calculating the optimal distance between the upper eyelid and eyebrow to achieve full or partial correction of ptosis. This method was tested in patients of different ages and genesis of disease.

Conclusion. Original model increased accuracy of surgical planning, reduced the risk of insufficient correction and hypercorrection, minimized the likelihood of corneal complications and provided aesthetically predictable results. The new method can be applied manually and using digital tools for ophthalmic surgeons.

Keywords. upper eyelid ptosis, ptosis correction, suspension procedures, surgical planning, anatomical and functional parameters, personalized ophthalmic surgery, mathematical model