Yes. By definition, glaucoma is a group of diseases which causes characteristic optic nerve damage with corresponding visual field defects. These defects are not always symptomatic to the patient and may only be detectable through special testing.
In advanced glaucoma. Glaucoma is a condition that is related to an increase in eye pressure. Over time, the optic nerve gets damaged and you start to lose peripheral vision (which shows up as field defects). So, initially you may have a normal field, but if left untreated, you will have field defects which are permanent.
Hopefully not. Glaucoma is diagnosed by a number of parameters of which the visual field is one. The goal of treatment is to prevent progression and this usually happens with good treatment. But sometimes a field defect is the clue to the presence of the condition, and changes in the field can be a clue to advancement of the therapy needed to treat the glaucoma.
Frequently. Changes in the field of vision are one of the hallmarks of the diagnosis of glaucoma. The aim of treatment is to prevent this from happening and also to prevent it when present from progressing. Some cases are detected early when other changes hint strongly that glaucoma could be a problem, and so field defects might not have occurred yet in such cases.
No. The defects occur after the increase pressure in your eye causes permanent damage to your vision. Usually you lose the peripheral vision. When it is bad you feel like looking through a tunnel when your peripheral vision is gone.
Not always. Some glaucoma patients display damage to the optic nerve inside the eye before the visual field is affected.
Good question! Glaucoma is a progressive optic neuropathy. What that means, is that it continues to get worse and cause more loss of vision. The visual field defects, once present, only continue to get worse. That is why the treatment is so important for holding on what you have.
No. Defects someone would notice in daily life would be late in the disease. Specialized visual field tests can show defects much sooner but still after damage has occurred. More specialized testing such as optical tomography can detect changes much sooner (ie, before visual field defects) and with appropriate treatment help preserve the vision.
No. Sometimes the elevated pressure will "eat away" at the myelin in the optic nerve causing an increase in the cup disc ratio before field damage occurs. This can give the patient a false sense of security and lead to noncompliance and subsequent damage.
Visual field loss. Certain conditions, i.e. glaucoma, cause loss of retinal sensitivity to portions of the peripheral vision. Macular disease affects central focusing vision. Visual field defects are usually monitored with an automated machine that measures a person's ability to see tiny spots of light in the peripheral and central vision. What we measure when a person reads a vision chart is central vision.
Depends on cause. There are many causes of vf defects. Some involve peripheral vision, some more central vision. If problem in intraocular, color vision can be associated.
Not directly. Some may have significant field defects with enough loss to compromise the color receptive portions of the retina. An example is retinitis pigmentosa, an inherited degeneration of the retina causing construction of the field of vision and loss of color vision. Ordinary color vision deficits are genetically determined and do not occur with field defects.
No. Many insurance companies are not covering for only loss of visual field. (medicare requires loss of levator muscle (true ptosis) or not pay. There are many degrees of vf loss, some will cover upper lid surgery when vf loss is >30% measured by vf analysis. Insurance co are following medicare lead and are denying except for muscle functional loss.
Not always. A visual field test which shows the blockage of the superior field of vision outside of certain limits can be the deciding factor as to whether insurance coverage is available for the procedure. The motivation to have this surgery however, is commonly cosmetic in which case the visual field is not the justification; but the appearance only.
Visual Field Loss. Hooding of the upper lid (mostly upper outer areas) are caused by elasticity loss and drooping. Forehead sagging and the lid elasticity loss are common causes. Visual field analysis is done in eye doctor offices, using an enclosure with many small lights and patient acknowledges seeking them light up in a closed background. This determines % of vf loss.
Optimitrist & Eye MD. Usually after a 20-30% reduction, difficulty with eye fatigue and loss of effective night vision is noted. Believed that excessive hooding to that level forces drivers to lift their head when driving at night, resulting in excessive glare and loss of "gray" colors needed for depth perception. Use of visual field analysis in most eye doctor offices can measure the degree of loss.
No. Most ophthalmologists have visual field testing devices in their office which can measure a field of vision for most pathologies. There is not a special "consultant" ophthalmologist for this purpose as the interpretation of visual fields is well studied and well known to ophthalmologists.