Cause of Pigment Dispersion Syndrome

Etiology of Pigment Dispersion Syndrome (PDS)

The purpose of this study is to learn how pigment is released from the iris (the colored part of the eye) in patients with pigment dispersion syndrome. It will do this by examining the response of the pupil (the central opening of the iris) to a flash of light to determine what is happening in the iris to cause release of the pigment.

In pigment dispersion syndrome, pigment released from the iris is deposited in other parts of the eye, including the trabecular meshwork-a filter-like tissue in the front of the eye. Aqueous fluid (fluid continuously produced by the eye) normally flows out of the eye through the trabecular meshwork. In some patients, the pigment deposits may block tiny holes in the meshwork, preventing the fluid from flowing out. This can cause an increase in eye pressure that may lead to glaucoma and some loss of vision. Understanding how pigment is released from the iris may help predict the course of pigment dispersion syndrome and identify which patients will likely develop increased eye pressure.

Patients with pigment dispersion syndrome and normal volunteers may be eligible for this study. All participants will have the following procedures, which will be completed in two clinic visits:

First visit

1. Examination of the front of the eyes, including the cornea, iris and lens.
2. Vision testing and measurements of visual field and eye pressure.
3. Examination of the trabecular meshwork. For this test, a contact lens is placed on the eye after the eye has been numbed with anesthetic drops.

Second visit

1. Refraction (dilation of the pupils with drops) and examination of the back of the eyes, including the optic nerve.
2. Reaction of the pupils to low-level infrared light (pupillography). During this 15-minute test, the patient or volunteer wears a lightweight headband with two small cameras mounted on it. The cameras-one which views the eye and the other the subject's field of view-record pupil dilation and position.

The test results in patients with pigment dispersion syndrome will be compared with those in normal volunteers. Patients will be followed every 6 months (or more often, if medically indicated) during the 3-year study to determine changes in eye pressure or visual field. Volunteers will be asked to return about once a year for 3 years for repeat pupillography.

Study Overview

• Status: Completed
• Conditions: Glaucoma; Healthy; Pigment Dispersion Syndrome

Detailed Description

The purpose of this study is to conduct a comprehensive ophthalmologic evaluation and comparison of two types of patients and to compare them to normal controls. The two types of patients are those with pigment dispersion (PDS) with normal intraocular pressure (IOP) and those with PDS and elevated IOP. The hypothesis to be tested is that a developmental abnormality of the iris pigment epithelium (IPE) and the dilator muscle is the fundamental defect responsible for the pigment dispersion. This defect may involve other structures of the eye such as the ciliary and retinal pigment epithelium. The results of pupillography in PDS with or without elevated IOP and asymmetric PDS (one eye versus fellow eye) will be the outcome parameters.

• Study Type: Observational
• Enrollment: 90

Contacts and Locations

Study Locations

• United States
  • Maryland
    • Bethesda, Maryland, United States, 20892
      • National Eye Institute (NEI)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

INCLUSION CRITERIA:

All patients entering the study must have black pigment deposition on the trabecular meshwork at the site of Schlemm's canal equal to or greater than 2-plus on the goniophotographic scale of 1 to 5 plus.

Although this condition is rare amongst African-Americans, every effort will be made to recruit such individuals.

EXCLUSION CRITERIA:

Patients with exfoliation syndrome, uveitis, trauma, pigment dispersion with posterior chamber intra-ocular lens, pigmented tumors, primary open-angle glaucoma, other conditions with associated pigment dispersion such as acute angle-closure glaucoma, ocular hemorrhage, Horner's syndrome.

In addition, normal volunteers will be recruited as controls. They will be free of any eye disease and be matched for age, sex and degree of myopia.

Study Plan

How is the study designed?

Collaborators and Investigators

• Sponsor: National Eye Institute (NEI)

Publications and helpful links

General Publications

• Ferris FL 3rd, Kassoff A, Bresnick GH, Bailey I. New visual acuity charts for clinical research. Am J Ophthalmol. 1982 Jul;94(1):91-6.
• Ferris FL 3rd, Sperduto RD. Standardized illumination for visual acuity testing in clinical research. Am J Ophthalmol. 1982 Jul;94(1):97-8. doi: 10.1016/0002-9394(82)90198-2. No abstract available.

Study record dates

Study Major Dates

• Study Start: June 1, 2000
• Study Completion: August 1, 2003

Study Registration Dates

• First Submitted: June 17, 2000
• First Submitted That Met QC Criteria: June 17, 2000
• First Posted (Estimate): June 19, 2000

Study Record Updates

• Last Update Posted (Estimate): March 4, 2008
• Last Update Submitted That Met QC Criteria: March 3, 2008
• Last Verified: August 1, 2003

More Information

Terms related to this study

• Keywords: Natural History; Ocular Hypertension; Glaucoma; Pigment Dispersion Syndrome; Gene Mutation; Pigment Dispersion; Pupil Reaction
• Additional Relevant MeSH Terms: Pathologic Processes; Eye Diseases; Disease; Ocular Hypertension; Glaucoma; Glaucoma, Open-Angle; Syndrome
• Other Study ID Numbers: 000155; 00-EI-0155