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Wednesday
Dec012010

Macular holes

A macular hole is a break in the central portion of the human retina.  Significant visual disturbance usually results.  In my experience, observant patients will come in complaining of a "hole" in their vision that they can not see through or around and that moves with gaze changes.  As with most medical conditions, this  can run the gamut as far as presentation and severity. 

Mostly, macular holes develop secondary to vitreal traction of some type.  With the aging process, the vitreous convolutes or degenerates.  As the back part of the vitreous, called the posterior hyaloid face, begins to separate from the retina, that open space facilitates development of something called an epiretinal membrane.  This membrane is a membrane secondary to aging in general and PVD, or posterior vitreal detachment.  An ERM, or epiretinal membrane, is made up of various inflammatory tissue such as proteins and leucocytes.  This is a non-uniform membrane that causes nasty problems for the top layer of the retina and will pull and distort the retina in various ways, invariably causing visual disturbance.

The Cirrus in our office can really show a high level detail for these.  Previously, to pick up on ERM's with "naked eye" examination, all the physician really sees is what appears to be cellophane wrinkling on top of the macula/retina.  It can be quite subtle at times.  But as you can see from the photos below, first a normal HD OCT scan, and 2nd an ERM, retinal distortion is quite obvious.  ERM's really are destructive to the underlying tissue as shown.

 So an ERM ultimately being the cause of a macular hole in most cases, lead to a macular hole staging/naming system.  It's called the Gass classifications.

Stage 1: the foveal pit/depression begins to be more difficult to see, and a small cyst forms below the retinal surface.

Stage 2:  Partial inner retinal breaks can be seen with a lid or operculum adhering to the sides of the hole.

Stage 3:  The lid (operculum) no longer adheres to the retina.  Now is when the physician will start to see retinal edema.

Stage 4:  Hole becomes full thickness. 

Treatment is done by a retinal surgeon and comes in the form of a vitrectomy/membrane peel.  This treatment has much better prognosis now than in the past with improving techniques, although the process is still no fun for the patient.  Vitrectomy is still a quite invasive surgery and should be respected as such.  We will discuss this more on a future post. 

 

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