1 post tagged “causes of macular hole”

A macular hole is a small hole in the macula which is in the centre of the retina. The macula is the part of the retina which is responsible for our sharp, detailed, central vision. This is the vision we use when we are looking directly at things, when reading, sewing or using a computer. Macular holes usually only affect one eye, though there is a 10 per cent, one in ten, chance that the other eye will eventually be affected.

Causes of Macular Hole

The most common cause of a macular hole is localized pulling on the retina by the vitreous — the clear, gel-like substance that normally fills the inside back of the eye. This tugging may initially cause mild blurring of vision as the retina becomes thinner. If an actual hole develops, people are aware of a small blind spot in their central vision.

Macular holes develop in stages, including: foveal detachments (stage I), partial-thickness holes (stage II), and full-thickness holes (stage III). A stage IV macular hole is an advanced full-thickness hole, with vitreous separation from the optic disc and macula.

Most of the eye's interior is filled with vitreous, a gel-like substance that fills about 80 percent of the eye and helps it maintain a round shape. The vitreous contains millions of fine fibers that are attached to the surface of the retina. As we age, the vitreous slowly shrinks and pulls away from the retinal surface. Natural fluids fill the area where the vitreous has contracted. This is normal. In most cases, there are no adverse effects.

Symptoms of Macular Hole

Macular holes often begin gradually. In the early stage of a macular hole, people may notice a slight distortion or blurriness in their straight-ahead vision. Straight lines or objects can begin to look bent or wavy. Reading and performing other routine tasks with the affected eye become difficult. 

In very rare instances, trauma or other conditions lead to the development of a macular hole. In the vast majority of cases, however, macular holes develop spontaneously. As a result, from traditional thinking there is no known way to prevent their development through any nutritional or chemical means, nor is there any way to know who is at risk for developing a hole prior to its appearance in one or both eyes. 

Treatment for Macular Hole

Although some macular holes can seal themselves and require no treatment, surgery is necessary in many cases to help improve vision. In this surgical procedure--called a vitrectomy--the vitreous gel is removed to prevent it from pulling on the retina and replaced with a bubble containing a mixture of air and gas. The bubble acts as an internal, temporary bandage that holds the edge of the macular hole in place as it heals. Surgery is performed under local anaesthesia and often on an out-patient basis.

Macular hole surgery with silicone oil tamponade is an option worth considering in cases with previous failed surgery (Group B), particularly in the presence of fellow eye pathology and if there are difficulties with posturing. This is because good anatomical closure rate can be achieved for these patients and there is substantial variability in visual improvement among eyes with successful closure of macular hole. Perhaps in future if we are able to predict the visual outcome for individual cases one can be more selective regarding candidates for reoperation.