Sorry if this is a well-known thing(?) but I’ve never read it before. I found that I can “see” the areas of sight loss by doing the following:
1) Fill a computer screen with white, e.g. by opening a new Notepad window and resizing to fill the screen.
2) Place the cursor in the middle of the screen.
3) Sit close the screen, about 12 to 15 inches away, so that the white screen fills a large portion of your vision.
4) Close both eyes for 10 seconds.
5) Open one eye and focus on the cursor without moving the eye around.
6) The area of lost vision builds over about 5 seconds to form a grey shadow over the white background, corresponding with the sight loss. After a further 5 to 10 seconds it begins to smear out, so stop looking then.
7) Repeat 4 to 6 as often as you want, and then for the other eye.
I could confirm that the grey shadow corresponds with sight loss by moving something like a pencil tip in and out of the grey areas and watching where it disappears.
I even tried sticking a sheet of clear plastic over the screen and drawing the boundaries of the grey area with felt pens. Tricky to do quickly during the few seconds available while it is visible, but I got a rough sketch that agreed with my perceptions of sight loss.
Again, sorry if you already knew this, or know of a better method, but it’s worth a try if its new to you.
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This doesn't seem to work well for me, but I do something similar to check my vision loss, which is central. I make a word document that is completely filled with different sentences (no paragraphs). I print it out and lay it down in front of the computer. I choose a word in the centre of the script and circle it on the paper. Then I cover one eye, and look steadily at the same word in the centre of the screen about 12-15 inches away. Then I move the cursor around, (keeping my eye fixed on the centre word), and when it disappears, I mark an X on the paper copy. I do this all over. Then I connect all the X's to make the shapes that show my vision loss. It is a bit tedious, but I have found that it shows my vision loss pretty accurately.
I've done something similar but using an excel spreadsheet. I stare at a central cell filled with black and move the cursor around and type into the cells where I can't see the cursor. It is time-consuming and hard to maintain a consistent head position, but I can map the sight loss this way too. (I actually find it easier and clearer to stare at the moving cursor and note where the central black cell disappears. This produces an image reflected in X and Y, so a screenshot needs reflecting horizontally and vertically in an image tool to match what I perceive). The method that I posted though gives me quite a good visualization in seconds.
How interesting we have both found a similar way to map our vision loss! I did try your quick method, but it did not really work for me. I could see some faint greyness, but not enough to discern much. I have lost quite a bit of central vision and I need a new glasses lens after surgery so that may have something to do with it. My optometrist (I see a glaucoma specialist as well of course) said I should pass on my method to one of the visual field test manufacturers. (I have not yet done so.) I have "Normal" Tension glaucoma, and I think you do too? I had been treated with eye drops for ten years, along with standard, predominately peripheral, visual field tests, with pressures of 16-18. I realized one day that I could no longer read with my right eye alone. That's when I started mapping the vision loss. (I have a 10-2 visual field test done every 6 months.) Is your vision loss central as well?
Yes, our history sounds similar. Normal tension, surgery in both eyes after 11 years on drops, pressures before surgery in mid-teens, eye test booked for next week. Right eye sight loss is like a ring-segment clockwise from 7 o'clock to 1 o'clock, the central vision is clear. The left is different, an area with vision like swiss-cheese (clear and loss) below an arc draw from 7 o'clock, though a point just below the centre, to 3 o'clock. Reading with just the left eye is slightly tricky, but rotating the text anti-clockwise a little helps, raising the text still to be read above the area with issues.
I think those ideas are absolutely brilliant! I've never tried the blank screen method myself. My first technique was to put a peg on a brightly coloured chopping board, focus on it, then add other pegs and small clips around it. I could slide several pegs into the 'Bermuda Triangle' a little below the central peg, so that they completely disappeared. This area got significantly bigger. However I felt I would sound unhinged if I tried to explain to my consultant that more pegs were now disappearing from my chopping board !
I think sticking squared paper onto my laptop screen and moving a pencil would work for me.
I too have normal tension Glaucoma and areas of vision loss all round the central focal point.
Hi! Fascinating posts! I’m curious why you feel the need to map your para central vision loss? Do you feel the consultants aren’t keeping ahead of deterioration of vision?
My diagnosis was POAG both eyes with vision loss 5 years ago, but after 2 yrs possible NTG was discussed. I’ve done the same mapping but I just identified the points of loss with my finger while staring at a white sheet of paper. I placed a cross and then joined the crosses and shaded in to depth of loss, as outer areas are patchy vision, but central area is more dense.
I did it to try and prove the patch was growing as the field tests didn’t appear to be detecting that. My consultants were impressed with the accuracy of my drawing. But still claim my vision loss isn’t worsening. 🤨 I’ve checked and they are using 10:2.
My vision loss which is paracentral in right eye takes about 20% of my vision in that eye in an arch from 10 clockwise to 3. The OCT shows that the nerves are becoming slightly damaged on my left in same location but not enough to show up in field test. I’m told when the left progresses, to match right, which is very likely, I will lose my medical driving licence and of course have significant vision issues.
I am checked usually about every 6 months. Except in lockdown. I think I lost a lot more vision then but consultant won’t quantify or confirm that.
I am on two drops 3 times a day and have had SLT. Trab discussion been raised but not yet felt needed. My consultant wants to exhaust all non major surgery options before he starts messing with my eyes. He says we have a long journey as I’m quite young and need to plan for the long haul. I trust this but every now and then lose faith in the testing and fear they underestimate actually how bad my vision loss is. Or that it is silently worsening and the technology isn’t picking it up as rapidly as my brain is. I park this thought most of the time in order to get on with life but your posts struck a cord . Hence my original question.
Hi Beecalmed. I suppose I had a range of motivations for trying to map the sight loss: curiosity; the challenge; education; self-monitoring; anxiety. Distrust of the hospital wasn’t one of them – their mappings are much better than anything I can manage. I haven’t actually created a full mapping of my own as it is time-consuming and tricky to get accurate, just a rough idea of extent.
I think the hospital checks are sensitive to change, so your specialist should be able to pick up if your left eye is worsening. For your own satisfaction you could see if you are able to create reproduceable mappings of your left eye in the areas that correspond with sight loss in your right. If you can detect and demonstrate change then you would have something tangible to discuss with your consultant. If you don't detect change then you could reassure yourself. Otherwise, I would just trust their visual field tests and try not to make yourself anxious (which is easier said than done, I know!)
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