The Silicone Study



Sponsors


Source

National Eye Institute (NEI)

Brief Summary

To compare, through a randomized, multicenter surgical trial, the postoperative tamponade
effectiveness of intraocular silicone oil with that of an intraocular long-acting gas
(initially sulfur hexafluoride [SF 6 ], later perfluoropropane [C 3 F 8 ]) for the management
of retinal detachment complicated by proliferative vitreoretinopathy (PVR), using vitrectomy
and associated techniques.

To evaluate the ocular complications that result from the use of silicone oil and gas.

Detailed Description

The treatment of retinal detachment complicated by PVR remains controversial. Although some
cases are managed successfully by pars plana vitrectomy and with temporary tamponade provided
by intraocular gas, others eventually redetach with this technique. Preliminary reports
indicate that prolonged tamponade with liquid silicone results in improved anatomical
success, but the eventual visual outcome may be prejudiced by silicone-related complications,
particularly glaucoma and keratopathy. The addition of hydraulic reattachment by simultaneous
fluid/gas exchange to vitrectomy surgery has proved to be an important development. Although
complications are few with these procedures, subsequent redetachment is frequent.

The Silicone Study was a randomized trial to investigate the relative merits of silicone oil
or gas as tamponade modalities. All study patients underwent vitrectomy and were randomized
intraoperatively either to silicone oil or to gas. Two groups of eyes were entered into the
study: eyes that had not had a prior vitrectomy (Group 1) and those that had undergone
previous vitrectomy outside the study (Group 2).

A critical element in the study was a standardized surgical procedure for PVR. This surgical
procedure, intended to relieve retinal traction with vitrectomy techniques, was followed by
assessment of the relief provided by an intraocular air tamponade. The eye was randomized to
silicone oil or gas only after completion of the entire surgical procedure to eliminate
investigator bias that might develop through knowledge of the treatment modality. Patients
were examined 5 to 14 days following the randomization and again at 1, 3, 6, 12, 18, 24, and
36 months after that date. Repeated surgery was permitted for either treatment modality. The
Fundus Photograph Reading Center staff processed and analyzed photographs taken at all the
clinics, graded the preoperative severity of PVR on the basis of baseline visit photographs,
and confirmed the macular status at followup visits.

End points of the study were visual acuity of 5/200 or greater and macular reattachment for 6
months following the final surgical procedure. The successful outcomes and complication rates
of the two modalities were compared.

Overall Status

Completed

Start Date

1985-09-01

Completion Date

N/A

Primary Completion Date

N/A

Phase

Phase 3

Study Type

Interventional


Conditions


Intervention

Intervention Type

Drug

Intervention Name



Intervention Type

Drug

Intervention Name



Intervention Type

Drug

Intervention Name




Eligibility

Criteria

Eligibility criteria included but were not limited to PVR of Grade C-3 or greater according
to the Retina Society Classification and visual acuity of light perception or better.

Gender

All

Minimum Age

N/A

Maximum Age

N/A

Healthy Volunteers

No


Verification Date

1999-10-01

Lastchanged Date

N/A

Firstreceived Date

N/A

Has Expanded Access

No

Condition Browse


Firstreceived Results Date

N/A

Reference

Citation

Lean JS. Changing attitudes in United States to use of intravitreal silicone. Jpn J Ophthalmol. 1987;31(1):132-7.

PMID

3626172


Citation

Glaser BM. Silicone oil for proliferative vitreoretinopathy. Does it help or hinder? Arch Ophthalmol. 1988 Mar;106(3):323-4.

PMID

3345147


Citation

Azen SP, Irvine AR, Davis MD, Stern W, Lonn L, Hilton G, Schwartz A, Boone D, Quillen-Thomas B, Lyons M, et al. The validity and reliability of photographic documentation of proliferative vitreoretinopathy. Ophthalmology. 1989 Mar;96(3):352-7.

PMID

2652029


Citation

Boone DC; Lai M; Azen S; Silicone Study Group; Clinical judgment and centralized data management., Controlled Clin Trials 1989;10:339


Citation

Irvine AR; Photographic documentation and grading of PVR, in Freeman HM, Tolentino FI (eds)., Proliferative Vitreoretinopathy, New York, Springer-Verlag 1989:105-109


Citation

Lean JS, Stern WH, Irvine AR, Azen SP. Classification of proliferative vitreoretinopathy used in the silicone study. The Silicone Study Group. Ophthalmology. 1989 Jun;96(6):765-71.

PMID

2662099


Citation

Barlow W, Azen S. The effect of therapeutic treatment crossovers on the power of clinical trials. The Silicone Study Group. Control Clin Trials. 1990 Oct;11(5):314-26.

PMID

1963127


Citation

Stern WH; Lean JS; Silicone Study Group; Intraocular silicone oil versus gas in the management of proliferative vitreoretinopathy (PVR): A multicenter clinical study, in Freeman HM, Tolentino FI (eds)., Proliferative Vitreoretinopathy, New York, Springer-Verlag 1989


Citation

Azen SP, Boone DC, Barlow W, McCuen BW, Walonker AF, Anderson MM, Lean JS, Mowery RL, Ryan SJ, Stern W. Methods, statistical features, and baseline results of a standardized, multicentered ophthalmologic surgical trial: the Silicone Study. Control Clin Trials. 1991 Jun;12(3):438-55.

PMID

1651213



Firstreceived Results Disposition Date

N/A

Study Design Info

Allocation

Randomized

Primary Purpose

Treatment


Study First Submitted

September 23, 1999

Study First Submitted Qc

September 23, 1999

Study First Posted

September 24, 1999

Last Update Submitted

June 23, 2005

Last Update Submitted Qc

June 23, 2005

Last Update Posted

June 24, 2005


ClinicalTrials.gov processed this data on August 22, 2018

Conditions

Conditions usually refer to a disease, disorder, syndrome, illness, or injury. In ClinicalTrials.gov, conditions include any health issue worth studying, such as lifespan, quality of life, health risks, etc.
Interventions

Interventions refer to the drug, vaccine, procedure, device, or other potential treatment being studied. Interventions can also include less intrusive possibilities such as surveys, education, and interviews.
Study Phase

Most clinical trials are designated as phase 1, 2, 3, or 4, based on the type of questions that study is seeking to answer:

In Phase 1 (Phase I) clinical trials, researchers test a new drug or treatment in a small group of people (20-80) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.

In Phase 2 (Phase II) clinical trials, the study drug or treatment is given to a larger group of people (100-300) to see if it is effective and to further evaluate its safety.

In Phase 3 (Phase III) clinical trials, the study drug or treatment is given to large groups of people (1,000-3,000) to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.

In Phase 4 (Phase IV) clinical trials, post marketing studies delineate additional information including the drug's risks, benefits, and optimal use.

These phases are defined by the Food and Drug Administration in the Code of Federal Regulations.



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