Are There Changes in the Nerve Fiber Layer (NFL) After Lowering of Eye Pressure?

Wills Eye

Status: Completed

Conditions: Glaucoma

Treatments: Diagnostic Test: Humphrey Visual Field (HVF); Diagnostic Test: Visual evoked potential (VEP); Diagnostic Test: Optical Coherence Tomography (OCT)

Study type: Observational

Funder types: Other

Identifiers

NCT02600403

11-058

Details and patient eligibility

About

The aim of this study was to evaluate structural and functional improvement after lowering intraocular pressure (IOP) in patients with glaucoma using Spectral Domain Optical Coherence Tomography (SD-OCT), Visual Field (VF) testing, and Visual Evoked Potential (VEP).

Full description

Glaucoma exhibits characteristic changes to the optic nerve in the back of the eye. The optic nerve is formed when fibers that overlay the retina come together. This layer is called the retinal nerve fiber layer (RNFL).

Optical Coherence Tomography (OCT) is a machine that scans eyes and has the capability of measuring thickness of various layers in the retina and RNFL. This provides important anatomical information.

VEP (visual evoked potential) is an imaging system that measures electrical signals from the eye to the brain by using electrodes placed on the forehead and back of head. This is similar in principal to an electrocardiogram of the heart.

Visual field testing is done to evaluate the extent of side vision loss caused by various diseases of the eye, including glaucoma. This testing is performed as you stare at a small light directly in front of your eye while lights flash one at a time in every direction on a screen surrounding the central light. You push a button each time you see a flash out of the corner of your eye.

Lowering intraocular pressure (IOP) in the eye has been shown to result in reversal of glaucoma changes of the optic nerve in some patients. It has also been suggested that improvement in function (visual field) has been associated with improved optic nerve appearance.

This study seeks to provide evidence for reversal of disc appearance and visual function following IOP lowering interventions.

Enrollment: 61 patients

Sex: All

Ages: 18 to 90 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• All patients with glaucoma (primary open-angle glaucoma, angle recession glaucoma, exfoliation syndrome glaucoma, pigmentary glaucoma and chronic angle closure glaucoma) in whom a pressure-lowering intervention was conducted

Exclusion criteria

• Inability to obtain reliable field or optical coherence tomography pre-intervention
• Visual acuity less than 20/40,
• Age <18 or >90 years,
• Other cause for visual field loss not glaucoma, that is, visual field loss due to cataract optic neuropathies, retinal disease
• Spherical equivalent refractive error > +5.00 Diopters and > 3.00 Diopters cylinder
• Concomitant cataract and glaucoma surgery

Trial design

61 participants in 3 patient groups

IOP between 22-32 mmHg

Description:

Forty four (44) patients with intraocular pressure between 22 and 32 millimeters (mmHg) of mercury will undergo Optical Coherence Tomography (OCT); Visual Evoked Potential (VEP); and Humphrey Visual Field (HVF).

Treatment:

Diagnostic Test: Optical Coherence Tomography (OCT)

Diagnostic Test: Visual evoked potential (VEP)

Diagnostic Test: Humphrey Visual Field (HVF)

IOP greater than 32 mmHg

Description:

Six (6) patients with intraocular pressure greater than 32 millimeters of mercury (mmHg) will undergo Optical Coherence Tomography (OCT); Visual Evoked Potential (VEP); and Humphrey Visual Field (HVF).

Treatment:

Diagnostic Test: Optical Coherence Tomography (OCT)

Diagnostic Test: Visual evoked potential (VEP)

Diagnostic Test: Humphrey Visual Field (HVF)

IOP less than 22 mmHg

Description:

Eleven (11) patients with stable intraocular pressure (less than 22 millimeters of mercury (mmHg)) on ophthalmic solutions (eye drops) will undergo Optical Coherence Tomography (OCT); Visual Evoked Potential (VEP); and Humphrey Visual Field (HVF).

Treatment:

Diagnostic Test: Optical Coherence Tomography (OCT)

Diagnostic Test: Visual evoked potential (VEP)

Diagnostic Test: Humphrey Visual Field (HVF)