This study is testing a new eye drop called **RGN-259** to see if it helps people with a condition called **Neurotrophic Keratopathy** (NK). NK is a disease where the eye loses feeling and gets less tears, making it hard for the eye surface to stay healthy. The study compares RGN-259 drops with placebo drops (which have no medicine). To join, you must be at least 18 years old and have an eye issue that doesn't heal with regular treatment.

Key Points:

• Participants will need to attend multiple study visits and follow instructions.
• Participants must not have certain eye conditions or recent eye surgeries.
• Women who can have children must use birth control and men must agree to use contraception.

If you have any conditions that might affect the study, like certain eye diseases, recent surgeries, or are using specific medications, you might not be able to join. Also, if you have allergies to the study drops or have been in other drug studies recently, you may not qualify. If you think you might be eligible, talk to your doctor to see if this study could be right for you.