---
title: "Exploration of Pupil Dilation in Horner's Patients Taking Flomax"
nct_id: NCT03615508
overall_status: TERMINATED
phase: PHASE4
sponsor: Denver Health and Hospital Authority
study_type: INTERVENTIONAL
primary_condition: Horner Syndrome
countries: United States
canonical_url: "https://parkinsonspathways.com/agent/trials/NCT03615508.md"
clinicaltrials_gov: "https://clinicaltrials.gov/study/NCT03615508"
ct_last_update_post_date: 2022-03-03
last_seen_at: "2026-05-12T06:00:45.885Z"
source: ClinicalTrials.gov (mirrored, no enrichment)
---
# Exploration of Pupil Dilation in Horner's Patients Taking Flomax

**NCT ID:** [NCT03615508](https://clinicaltrials.gov/study/NCT03615508)

## Key Facts

- **Status:** TERMINATED
- **Why Stopped:** incomplete enrollment
- **Phase:** PHASE4
- **Study Type:** INTERVENTIONAL
- **Target Enrollment:** 1
- **Lead Sponsor:** Denver Health and Hospital Authority
- **Collaborators:** University of Colorado, Denver
- **Conditions:** Horner Syndrome
- **Start Date:** 2018-09-21
- **Completion Date:** 2019-05-01
- **CT.gov Last Update:** 2022-03-03

## Brief Summary

This study is evaluating the pupil dilation of Horner's Patients who have ever taken an alpha blocker such as Tamsulosin. Patients will undergo eye dilation as would occur at a yearly eye examination, but their pupil dilation measurements will be recorded.

## Detailed Description

This study will enroll 10 participants who have a unilateral Horner's Syndrome AND have a history of taking an alpha blocker such as Tamsulosin. Participants will be recruited based on those two enrollment criteria, and after consenting they will undergo pupil dilation with 10% phenylephrine. Once fully dilated the pupil size will be measured. Pupil dilation size of the eye affected by the Horner's Syndrome will be compared to the eye not affected by Horner's. Primary study outcome is the comparative dilation size of the Horner's affected eye to the non affected eye in all subjects.

## Eligibility

- **Minimum age:** 18 Years
- **Sex:** ALL
- **Healthy Volunteers:** Yes

```
Inclusion Criteria:

1. Horner's Syndrome
2. History of taking an alpha blocker (tamsulosin/ terazosin/doxazosin/alfuzosin/silodosin) medication

Exclusion Criteria:

1. Subjects with untreated hypertension
2. Subjects with thyrotoxicosis
3. Pregnant women
4. Prisoners
5. Inability to consent
6. Subjects with anatomical narrow angles who have never had a dilated exam
```

## Arms

- **10% phenylephrine** (OTHER) — All patients will receive 10% phenylephrine at their eye examination as the drug to dilate the pupil. After pupil dilation, pupil size will be measured.

## Interventions

- **10% phenylephrine** (DRUG) — 10% phenylephrine is a drug that can be used to dilate patient's eyes at their yearly eye examination. All enrolled subjects will receive this drug for their eye dilation.

## Primary Outcomes

- **Pupil Size Measurements** _(time frame: 20-30 minutes after 10% phenylephrine has been placed in each eye.)_ — pupil dilation measurements will be taken of each eye at the eye examination.

## Locations (2)

- University of Colorado Hospital, Rocky Mountain Lions Eye Institute, Denver, Colorado, United States
- Denver Health, Denver, Colorado, United States

## Recent Field Changes (last 30 days)

- `design.enrollmentCount` — added _(2026-05-12)_
- `design.phases` — added _(2026-05-12)_
- `status.overallStatus` — added _(2026-05-12)_
- `status.whyStopped` — added _(2026-05-12)_
- `status.primaryCompletionDate` — added _(2026-05-12)_
- `status.completionDate` — added _(2026-05-12)_
- `status.lastUpdatePostDate` — added _(2026-05-12)_
- `eligibility.criteria` — added _(2026-05-12)_
- `eligibility.minAge` — added _(2026-05-12)_
- `eligibility.sex` — added _(2026-05-12)_
- `outcomes.primary` — added _(2026-05-12)_
- `armsInterventions.arms` — added _(2026-05-12)_
- `armsInterventions.interventions` — added _(2026-05-12)_
- `sponsor.lead` — added _(2026-05-12)_
- `sponsor.collaborators` — added _(2026-05-12)_
- `results.hasResults` — added _(2026-05-12)_
- `locations.university of colorado hospital, rocky mountain lions eye institute|denver|colorado|united states` — added _(2026-05-12)_
- `locations.denver health|denver|colorado|united states` — added _(2026-05-12)_

---

*Canonical: https://parkinsonspathways.com/agent/trials/NCT03615508.md*  
*Source data (authoritative): https://clinicaltrials.gov/study/NCT03615508*  
*This page is a raw mirror with no AI summary, no editorial enrichment, and no Parkinson's-specific filtering.*