Ischemic Optic Neuropathy Decompression Trial (IONDT)

Ischemic Optic Neuropathy Clinical Trial

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00000127
• Other study ID #: NEI-26
• Status: Completed
• Phase: Phase 3
• First received: September 23, 1999
• Last updated: March 23, 2010
• Start date: October 1992
• Est. completion date: October 1994

Study information

• Verified date: September 2009
• Source: National Eye Institute (NEI)
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Federal Government
• Study type: Interventional

Clinical Trial Summary

To assess the safety and efficacy of optic nerve sheath decompression surgery for non-arteritic ischemic optic neuropathy (NAION).

Description:

Non-arteritic ischemic optic neuropathy (NAION), the most common cause of acute optic nerve disease in older persons, causes permanent and severe visual loss. Visual function can be impaired through decreased central visual acuity or peripheral field loss, or both. NAION strikes both eyes in up to 40 percent of affected patients. The incidence of NAION has been estimated at 2.3 per 100,000 persons over the age of 50 years and 0.54 per 100,000 for all ages. Estimates of the number of new cases seen each year in the United States range from a low of approximately 1,500 to a high of 6,000.

NAION has been hypothesized to be caused by vascular insufficiency leading to optic nerve head ischemia. There is general agreement that NAION results from transient non-perfusion of nutrient vessels. The wide range of visual field defects and visual loss with NAION can be explained by the extent and number of the blood vessels involved.

Anatomical factors appear to contribute to the vascular event initiating NAION. Clinically, the number of discs congenitally lacking a physiological cup in eyes with NAION is higher than expected. Presumably, in eyes with NAION, these discs have small scleral openings that crowd the nerve fibers as they pass through the restricted space in the optic disc and lamina cribrosa, thereby predisposing to an ischemic spiral.

One current theory holds that NAION begins as a minor ischemic event that later progresses to a major infarction due to congenitally anomalous optic nerves. The inciting ischemic event leads to local anterior nerve edema, and this causes further ischemia.

Optic nerve sheath decompression surgery was reported in 1989 to be of benefit to patients with NAION. The presumed mechanism of action in optic nerve decompression surgery revolved around restoration of impaired blood flow to the optic nerve through reduction of the pressure around the nerve.

The Ischemic Optic Neuropathy Decompression Trial (IONDT) was a randomized clinical trial designed to compare the improvements in visual acuity at 6 months in patients assigned to receive surgery with optic nerve sheath decompression with those assigned to careful followup. A cohort of patients, with a baseline visual acuity of better than 20/64 are also being followed to better understand the natural history of the disease, including second eye involvement.

Enrollment began in October 1992. Randomization was stratified by clinic, and patients had an equal probability of assignment to surgery or careful followup. All patients are being followed for a minimum of 2 years.

The primary outcome is a change of three lines or more in visual acuity at the 6-month followup visit compared with visual acuity measured at the randomization visit.

Secondary outcomes include a change in visual acuity beyond 6 months, change in peripheral visual function as measured by automated Humphrey perimetry, local and systemic side effects from treatment, change in quality of life, and other associated morbidity and mortality.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 0
• Est. completion date: October 1994
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 50 Years and older

Eligibility

Men and women age 50 years or older, with acute NAION and visual symptoms for 14 days or less since the onset of symptoms, and visual acuity worse than or equal to 20/64 were eligible for randomization.

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Ischemia
• Ischemic Optic Neuropathy
• Optic Nerve Diseases
• Optic Neuropathy, Ischemic

Intervention

Procedure:
• Optic Nerve Sheath Decompression Surgery

Locations

Country	Name	City	State
n/a

Sponsors (1)

Lead Sponsor	Collaborator
National Eye Institute (NEI)

References & Publications (7)

Characteristics of patients with nonarteritic anterior ischemic optic neuropathy eligible for the Ischemic Optic Neuropathy Decompression Trial. Arch Ophthalmol. 1996 Nov;114(11):1366-74. — View Citation

Crawley B; Scherer RW; Ischemic Optic Neuropathy Decompression Trial (IONDT): Participation in the IONDT. Race, gender and age. [Abstract]., Controlled Clinical Trials 1994;15:102S

Crawley B; Waring MT; Scherer RW; Coordinating Center for the Ischemic Optic Neuropathy Decompression Trial (IONDT): IONDT tracking system: Where is form 2034 for patient ICMORE and who is responsible? [Abstract]., Controlled Clinical Trials 1994;15:93S

Kaufman D; Ischemic Optic Neuropathy Decompression Trial Study Group; Optic nerve decompression surgery for nonarteritic ischemic optic neuropathy (NAION is not effective and could be harmful: Results of the Ischemic Optic Neuropathy Decompression Trial (IONDT). [Abstract]., Invest Ophthalmol Vis Sci 1995;36:S196

Optic nerve decompression surgery for nonarteritic anterior ischemic optic neuropathy (NAION) is not effective and may be harmful. The Ischemic Optic Neuropathy Decompression Trial Research Group. JAMA. 1995 Feb 22;273(8):625-32. — View Citation

Scherer RW; Crawley B; Abstracts for the Ischemic Optic Neuropathy Study Group; Responses to ethical and other questions on a knowledge assessment form for a multicenter trial. [Abstract]., Controlled Clinical Trials 1993;14:442S

The ischemic optic neuropathy decompression trial (IONDT): design and methods. Control Clin Trials. 1998 Jun;19(3):276-96. — View Citation

External Links

•   Clinical Alert to Ophthalmologists and Neurologists
•   NEI Press Release-Eye Surgery Found Ineffective and May be Harmful -- Study Halted