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Medical Forum / General / Vision / January 2007Darkened spot and blurriness
A couple days ago, my cousin (in his mid-thirties) noticed that he ha a well-defined, darker spot in the center of his field of vision fo one eye. His vision in that eye is also a little blurry. Thes things are noticable day and night. His mother has had cataracts his grandmother has macular degeneration. Is it likely he has one o those? (He has high cholesterol that is being controlled wit medication. His BP, cholesterol and weight are all good.) Who woul be the best person to see for a diagnosis? And, should he think abou getting disability insurance Thanks in advance Neither one of those, but it could be a retinopathy, unless it seems to "float" or move when his eye is stationary, which could mean just a floater. Needs to be seen by an eye doc, and insurance may be a good idea, but probably too late, unless he fudges the date of first onset (aka insurance fraud)... >A couple days ago, my cousin (in his mid-thirties) noticed that he has >a well-defined, darker spot in the center of his field of vision for [quoted text clipped - 13 lines] > > William Thank you for your reply. After reading about central serou retinopathy (he is not diabetic nor does he have high BP), it sound like it describes his symptoms and situation very well. I am sure i will be reassuring to him (since it has a much better prognosis tha macular degeneration!) until he is able to see a doctor Thank you > Thank you for your reply. After reading about central serous > retinopathy (he is not diabetic nor does he have high BP), it sounds > like it describes his symptoms and situation very well. Just curious, how does this all lead to this conclusion? Don W. > Don Wwrote [quote:606e91159d > Thank you for your reply. After reading about central serou > retinopathy (he is not diabetic nor does he have high BP), i sound > like it describes his symptoms and situation very well Just curious, how does this all lead to this conclusion Don W.[/quote:606e91159d Which conclusion? If he has retinopathy, it is likely to be central serous retinopathy. From what I read, there are 4 types: retinopathy of prematurity diabetic retinopathy, hypertensive retinopathy, and central serou retinopathy. He's not an infant, nor diabetic, nor hypertensive. I am not sure how William came to the conclusion that it could b retinopathy, but the risk factors and symptoms I read about that see to apply to my cousin are Male between 20-4 Stres Reduced visual sharpness/blurrines Distortion (very very slight in my cousin's case Grey or blind spot Excuse. I was impressed as to how fast macular degeneration was ruled out. But the odds are it would be age related and I did not note his age range. Hopefully it is not that. With this type of symptom occuring, I would be in the doctor's office as soon as possible. Good luck. Don W. Mac. degen does not ordinarily cause a positive scotoma (one that the patient "sees" as a spot in the vision). I know some illustrators often simulate the disease using a dark or black spot in the center of the view. This is not what Mac Degen people see. It would better be portrayed with the detail in the scotoma area just having the same color as that surrounding the defect. (e.g. a face with missing eyes, nose and mouth shown with the featureless area the same skin tone as the rest of the face). Central serous retinopathy often does cause a positive dark scotoma such as is often erroneously depicted as macular degeneration. w.stacy, o.d. > Excuse. I was impressed as to how fast macular degeneration was >ruled out. But the odds are it would be age related and I did not note [quoted text clipped - 5 lines] > > > Mac. degen does not ordinarily cause a positive scotoma (one that the > patient "sees" as a spot in the vision). I know some illustrators often [quoted text clipped - 7 lines] > > w.stacy, o.d. Dear Dr. Stacy, That is completely untrue. The natural blind spot (optic nerve) may "fill in", but in "Mac Degen" the spot can be dark or black. Don W. PS. And the person experiencing this should see an ophthalmologist, very quickly. I suppose it "can appear dark or black" but most patients I've run across with macular degeneration don't report that. Most mac. degen. occurs very slowly and the losses associated are usually "filled in" in a manner very similar to that of the normal blind spot, or indeed, of the Purkinje tree itself. I thinkd this is the very reason that most macular degeneration patients have the "dry" type and first complain more of a blur or an indistinctness of fine detail or of straight lines appearing wavy or bent. Now a sudden hemorrhage like one might get from the much rarer "wet" form probably would cause a dark positive scotoma, but I don't see many of those (thankfully). Other docs here might want to chime in on this, since many of them may see more of this than I do. My patient population is pretty young, average age is about 42. w.stacy, o.d. > > [quoted text clipped - 23 lines] > > > I suppose it "can appear dark or black" but most patients I've run > across with macular degeneration don't report that. Most mac. degen. [quoted text clipped - 10 lines] > > w.stacy, o.d. The problem is with the symptom, one does not know how things will evolve (quickly or slowly) in time. I have one reference that shows "successful outcomes" depend on moving fast for treatment. They plotted a graph where the x-axis was calibrated in _days_. Which tells me you really have to move on this, insurance or not. Really, what do you have to lose?? As to the Purkinje tree vascular event, that can be negated by moving the light source across the retina where the vascular shadows are then cast in a "slightly new (small offset) area". Where the brain is not prewired as in the old area to compensate for their presence in front of the retina. As far as scotomas being filled in. Not usually so. I think it is too new an event for the brain to adapt. Don W. > > The problem is with the symptom, one does not know how things will > evolve (quickly or slowly) in time. I have one reference that shows > "successful outcomes" depend on moving fast for treatment. Ok it seems that you must be talking about the wet or proliferative type of macular degeneration, where things can indeed happen fast and early intervention is necessary. Certainly moving fast is not an issue with the common dry type of macular degeneration, as it is an exceedingly slow process. They > plotted a graph where the x-axis was calibrated in _days_. Which tells > me you really have to move on this, insurance or not. Really, what do > you have to lose?? I do recognize the importance of early intervention in such a case. But I also know that this is by far the rarer situation. The more common type takes years to develop and that this the type that I was talking about, where positive scotomata would be the exception. > As to the Purkinje tree vascular event, that can be negated by moving > the light source across the retina where the vascular shadows are then > cast in a "slightly new (small offset) area". More a phenomenon than an event, any localized deficit of retinal function can be visualized by strongly illuminating an adjacent normal retinal area. Where the brain is not > prewired as in the old area to compensate for their presence in front > of the retina. I think it's more a retinal level (ganglion cell, etc.) phenomenon than a cortical one. The recovery times for such things as the Purkinje tree is so fast as to be hardly considered a "prewired" situation. > As far as scotomas being filled in. Not usually so. I think it is > too new an event for the brain to adapt. Like I said, the Purkinje phenomenon is a great example of such relatively instantaneous adaptation. Shift the shadow a bit with a strong oblique light source, and what is at first a dramatic visualzation disappears within a second or so. Too fast for any rewiring to take place higher up, that's for sure. It's all at the ganglion level, right down in the retina itself. When the spot occurs, such as the case here, I would not consider this ("well defined dark spot") a possible manifestation of dry MD. But the possibility of wet MD would bother me. Agreed, moving fast is not necessary with dry MD. But it is not sure here how this symptom evolved in time. You comments on the Purkinje effect are interesting. I agree the effect is transitory, lasting for a fraction of a second or so, at least how I have noticed it. Then the incoming light is compensated for, that is, one does not see the vascular tree. That to me seems kind of a wonder, because during the normal day, light rays will strike this area around the vascular tree at various (mostly random) angles, and yet no image of the tree is produced ("seen"). But move a light from a slit lamp across it and there it is produced. But as far as scotoma is concerned, there is no compensation for the missing field. I hope you agree. Don W. > kind of a wonder, because during the normal day, light rays will strike > this area around the vascular tree at various (mostly random) angles, But it doesn't. Normally the shadow doesn't move and the retina loses all perception of edges that do not move. Wiggle a light (slit lamp, penlight, even through the sclera) and the shadows become perceptible. Floaters are visible because, suspended in jelly, they're seldom perfectly still. And referencing a previous conversation - floaters are more visible when the pupil is small because a bare light bulb casts a more distinct shadow than a diffused fluorescent fixture. Small sources make better shadows, regardless of the amount of light. That's why floaters are more visible in bright daylight - your pupils get smaller. -MT > > kind of a wonder, because during the normal day, light rays will strike > > this area around the vascular tree at various (mostly random) angles, > > But it doesn't. Normally the shadow doesn't move and the retina loses all > perception of edges that do not move. Wiggle a light (slit lamp, penlight, > even through the sclera) and the shadows become perceptible. So what you are saying is that if one modulates the shadows edge, (that is, turn the edge on and off) the vasculature will appear? Don W. True, or move the edge a bit as he said. The most dramatic display of this is when you manage to hold the eye perfectly still, all detail vision fades away. The vision system depends on a moving image for vision to occur. That's the reason we have what's called micronystagmus or physiologic nystagmus. w.stacy, o.d. > > [quoted text clipped - 16 lines] > > to be more correct, I should have said vision requires a changing image, either in intensity (on/off) or in position (motion). And that fade out with the still eye only takes a second or so. > to be more correct, I should have said vision requires a changing image, > either in intensity (on/off) or in position (motion). And that fade out > with the still eye only takes a second or so. Getting back as to what constitutes seeing or not seeing the retinal vascular. If modulation of the edges (on - off) is the same as moving the edges, then the eye going from a dark environment to bright light should produce at least a brief flash of these trees. I've never noticed this although it seems that should happen. Don W. PS. Yes I have read that fixing the retinal image makes the image disappear. I think also that direct retinal displays need built in jitter. There has been a paper (Deruaz) that discusses fixation instability to improve the vision (letters) of people with central scotomas. I think I know someone that has "improved" their vision from 20/200 to 20/100 by this kind of "trick". absolutely it happens. if you haven't seen it, you don't have the light at the right angle. It is only momentary, which is why moving the light helps the visualization since a single presentation is not as good as many in rapid succession, just like in the movies. > > [quoted text clipped - 20 lines] > > btw the conditions that I have experienced it is wearing very dark sunglasses (too dark, really) and catching a ray of sunlight from beyond the edge of the sun lens. Flashes a very bright P. tree on the darkness of the sun lens. Don't try this while driving.... > > So what you are saying is that if one modulates the shadows edge, (that > is, turn the edge on and off) the vasculature will appear? On-and-off isn't exactly the same as movement. I don't remember seeing Purkinje's tree in strobe lights, but I suppose you could. If you immobilize an eye completely, then vision quickly shuts down. The retina contains layers forming receptive fields, and interconnections between them. The interconnections function to balance and equilibrate the neural signal on either side of a dark-light border, with a pretty short time constant. The Wiki article on "Troxler effect" has a good discussion. This is one example of the pre-processing that occurs in the retina. It goes further, such that individual neurons in the optic nerve do not transmit individual "pixel" information. Instead of telling the brain "there's a dot in this location", each neuron says something more like "there's a line with orientation x moving in direction y." -MT > Excuse. I was impressed as to how fast macular degeneration was > ruled out. But the odds are it would be age related and I did not note [quoted text clipped - 3 lines] > > Don W. My husband was first diagnosed with central serous retinopathy, and then sent to another specialist who diagnosed a choroidal hemangioma which was treated with PDT. In either case, it seems to me the chance of recovering full vision diminishes the longer a person waits to see a doctor. As it was explained to me, the longer the retina is elevated, the greater the chance it will not flatten again completely. My husband wishes he had seen the retina specialist much sooner than he did. -Gudrun |
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