Answer
Yes. It can gradually increase brown pigmentation in the iris, especially in mixed-colour eyes. The change may be permanent and can look uneven if only one eye is treated.
Sources for this answer
- Bimatoprost/Timolol Aspire 0.3mg/ml + 5mg/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.