Answer
Closing the eye and pressing beside the nose reduces drainage into the bloodstream, which may reduce systemic side effects while keeping more medicine in the eye.
Sources for this answer
- Travoprost/Timolol Mylan 40 micrograms/ml + 5 mg/ml eye drops, solution — Current selected SmPCemc · Summary of Product Characteristics
- NHSNHS · NHS medicine guidance
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.