Answer
Pressing beside the nose with the eye closed reduces drainage into the bloodstream, which may lower systemic side effects while retaining the local effect.
Sources for this answer
- NHSNHS · NHS medicine guidance
- TIOPEX timolol 1 mg/g, eye gel in single-dose container — Current selected SmPCemc · Summary of Product Characteristics
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.