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Recruiting for New Studies

Question:

Hi all; Dr. Robert Ritch passes along comments from Dr Ishikawa, Director of the Imaging Center, about the visual field program for the PC recently mentioned here. I tried. My impression is as follows: 1. The program is small and handy, but the test totally depends on the size of monitor and the distance between eyes and monitor. 2. Usually, computer monitors are not calibrated to an uniform brightness and color hue, then results vary due to this. 3. The test does not have fixation check nor false positive and negative checks. 4. Testing points are distributed in even distance even at very peripheral area. The result of my testing suggested that I might have severe hemi-field defect on both eyes. This test may be useful to terrify patients with very bad result and encourage them to come to see doctors. And this can be a good starter for older people to be introduced to video game world. I have no academic or scientific interest on this program. Regards,

Response:

Rick:  I tend to agree with your comments, with perhaps some exceptions. First of all, such a program is inherently simple and therefore *should not* cost very much.  In fact, a halfway decent C++ programmer with a couple of days to spare could do the job. Next, I would not think of this as a replacement for a Humphrey perimeter. What is proposed here is a very simple home screening device.  It has obviously several shortcomings, including those in your comments below. Considering the typical 14-inch monitor and a 14-inch viewing distance, if the fixation point is in the center of the screen, the maximum angular coverage would be arctan (7/14) which is about 26 degrees.  With a fixation point at one corner of the screen, it would be possible to explore the field out to about 45 degrees. Then, one would have to change the fixation point in order to cover the field. There would be no simple way to determine whether the patient was fixated at the time of the measurement. Likewise, control of brightness would be a problem. By the way, all of this was investigated (superficially) by SRI’s bioengineering group about 15 years ago, perhaps longer. (That’s formerly Stanford Research Institute). There are better algorithms for exploring the field than just fixating on a point and hitting the space bar if you see a "twinkling light". It has been proposed several times since. My personal opinion is it *would* work.  Just as I do not substitute my home blood pressure machine for a visit to my cardiologist, I would not expect any PC-based field test to substitute for visits to my ophthalmologist. But one could get an idea that there might be a scotoma lurking out there somewhere and then go and get a *real* field test. I’ll send you some write-ups on the subject.  I don’t want to post them here, because they are based on mostly theory (and hand-waving) and not on real experimentation. regards, earle — In article <1998080204335100.AAA20…@ladder03.news.aol.com>, eyegu…@aol.com (EyeGuyRC) wrote: >I would be quite concerned about any computer program that allows you to "check >your visual field at home" via a personal computer for several reasons: 1) the >illumination of the stimulus and backround of visual field machines used in our >offices is standardized, which, of course, would not be the case in one’s >computer room at home.  2) different size computer monitors would allow for >differences in where points would be tested relative to the fixation point.  3) >Even if one could account for different size monitors and distances between the >patient and the screen,home monitoring simply cannot test for the  peripheral >points well compared with the dome-shaped visual field machine.  Not a problem >to try this home monitoring on occasion, but I wouldn’t pay good money to >purchase a program, and I wouldn’t use it to replace monitoring in the office. >Rick Cohn, MD >glaucoma specialist

               __             __/_            /_/_/              /_/_   earle               /_/   jones We want our Internet back!  Get rid of Spam.    See http://www.cauce.org

Response:

new diagnosee’ with this.  am in dallas are.  any info????? would be most appreciated.  am told have damage consistent with glaucome, but have NT & taht NTG is SO rare that it (NTG) could not possibly be the source of problem. Meanwhile, wait 3 months, lose more vision, and wailt ’til fit into this doc’s mold.  Not happy! Comments???

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    Not happy with doc?  Get yourself to one who’s a better fit for you. – Hide quoted text — Show quoted text -RobnrnDon1 wrote: > new diagnosee’ with this.  am in dallas are.  any info????? would be most > appreciated.  am told have damage consistent with glaucome, but have NT & taht > NTG is SO rare that it (NTG) could not possibly be the source of problem. > Meanwhile, wait 3 months, lose more vision, and wailt ’til fit into this doc’s > mold.  Not happy! > Comments???

Response:

I would be quite concerned about any computer program that allows you to "check your visual field at home" via a personal computer for several reasons: 1) the illumination of the stimulus and backround of visual field machines used in our offices is standardized, which, of course, would not be the case in one’s computer room at home.  2) different size computer monitors would allow for differences in where points would be tested relative to the fixation point.  3) Even if one could account for different size monitors and distances between the patient and the screen,home monitoring simply cannot test for the  peripheral points well compared with the dome-shaped visual field machine.  Not a problem to try this home monitoring on occasion, but I wouldn’t pay good money to purchase a program, and I wouldn’t use it to replace monitoring in the office. Rick Cohn, MD glaucoma specialist

Response:

"Walter Steuber" <wal…@steuber.com> wrote: >A computer program that can be downloaded free from >http://home.steuber.com/walter will let you measure your visual field and >follow changes in it over time.  Give it a try and tell me what you think.

This I must try, I will check it out! Viv

Response:

Hi; robnrnd…@aol.com (RobnrnDon1) wrote: >new diagnosee’ with this.  am in dallas are.  any info????? would be most >appreciated.  am told have damage consistent with glaucome, but have NT & taht >NTG is SO rare that it (NTG) could not possibly be the source of problem. >Meanwhile, wait 3 months, lose more vision, and wailt ’til fit into this doc’s >mold.  Not happy! >Comments???

Dr. Robert Ritch states that NTG is not rare. It’s about 25% of open-angle glaucoma.

Response:

On 2 Aug 1998 04:33:51 GMT, eyegu…@aol.com (EyeGuyRC) wrote: >I would be quite concerned about any computer program that allows you to "check >your visual field at home" via a personal computer for several reasons: 1) the >illumination of the stimulus and backround of visual field machines used in our >offices is standardized, which, of course, would not be the case in one’s >computer room at home.  

The basic concern would be the sensitivity and specificity, not what MDs or ODs think are good standards. >2) different size computer monitors would allow for >differences in where points would be tested relative to the fixation point.  

Well, certainly the program and its instructions can be made to take care of that.  Definitely *not* a problem. >3) >Even if one could account for different size monitors and distances between the >patient and the screen,home monitoring simply cannot test for the  peripheral >points well compared with the dome-shaped visual field machine.  

That is pure bull.  In the first place, if the intent is restricted to detecting glaucoma defects (the intent mentioned in respect to this program),  by the time such sight loss should ever reach that point, one wouldn’t bother tracking it any longer.  Furthermore, this program facilitates checks out to some 32 deg horizontally, on a 15-in monitor, at a viewing distance of 15 in.  That’s suffient for most purposes. >Not a problem >to try this home monitoring on occasion, but I wouldn’t pay good money to >purchase a program,

This programmer is not asking money for his work. >and I wouldn’t use it to replace monitoring in the office.

Well, I think we already know that.  I assume you’re one of the ones who worship the Goldmann bowl — as others do the copper-line pyramid with a crystal at its perfect point. However, I tried this program, and at its present level of development, I could not get it to work at all.  It does have, however, some design features that, with a lot for straightforward fixes and maybe a few more complex ones, could produce better results than a Humphrey machine with one of those soup bowls. Ray

Response:

Hi all; I posted this at the end of a message several days ago.  Thought it warranted a repost: Dr. Robert Ritch announces that he is recruiting for two new studies. 1. REGULA – a prostaglandin analogue used in Japan, similar to Xalatan, but not supposed to change iris color. Patients can never have had a single drop of Xalatan. If anyone has avoided Xalatan because of a possible color change and wants to try REGULA, contact us. 2. Timolol versus Alphagan (brimonidine) in normal-tension glaucoma. Timolol lowers IOP better than brimonidine. Brimonidine may lose its effect. However, brimonidine is believed to have neuroprotective activity. Which is more important in NTG? We are randomizing patients with NTG to treatment either with timolol or brimonidine and following visual fields for 3 years. This study is being done in New York, Chicago (Ted Krupin, MD), Indianapolis (Louis Cantor, MD), Houston (Ronald Gross, MD), Gainesville (Mark Sherwood, MD), Milwaukee (Dale Heuer, MD), and Philadelphia (George Spaeth, MD). Private (Admin Asst: Kat) – Tel: 212-673-5140 Patient Appointments – Tel: 212-477-7540 Fax: 212-420-8743 e-mail: ri…@inx.net

Response:

Earle Jones commented on the home field testing program, saying in part: >Considering the typical 14-inch monitor and a 14-inch viewing distance

Ah, but run the video from your computer into a standard television set and, voila, you have 27 inches, or if you have a projection system, 50, 72, 96 or 120 inches. I do this with an older computer and an RF converter from Radio Shack which cost around $20 I believe. There are cards or boxes available many places to convert any computer to TV video. Also, since I never graduated from Basic, that language could produce random dots quite easily with hitting a key being the signal that you saw it. Who knows, it might even be BETTER than the lab field test device.

Response:

A computer program that can be downloaded free from http://home.steuber.com/walter will let you measure your visual field and follow changes in it over time.  Give it a try and tell me what you think.

Response:

On 02 Aug 1998 14:10:02 EDT, ejone…@concentric.net (Earle Jones) wrote: >Rick:  I tend to agree with your comments, with perhaps some exceptions. >First of all, such a program is inherently simple and therefore *should >not* cost very much.  In fact, a halfway decent C++ programmer with a >couple of days to spare could do the job.

This one appears to be in Visual Basic. >Next, I would not think of this as a replacement for a Humphrey perimeter. >What is proposed here is a very simple home screening device.  It has >obviously several shortcomings, including those in your comments below. >Considering the typical 14-inch monitor and a 14-inch viewing distance, if >the fixation point is in the center of the screen, the maximum angular >coverage would be arctan (7/14) which is about 26 degrees.  With a fixation >point at one corner of the screen, it would be possible to explore the >field out to about 45 degrees. Then, one would have to change the fixation >point in order to cover the field.

This program does switch the target to the 4 corners of the monitor for testing each quadrant in sequence. >There would be no simple way to determine whether the patient was fixated >at the time of the measurement.

I don’t see why such a program couldn’t use the physiological blind spot to monitor fixation, the same way that other perimeters do.  This one, however, doesn’t presently incorporate this ability.  BTW, Dr. Horn’s program has fixation monitoring: http://www.thevisionplace.com/VisionPlaceIII/diagnose/frmain.htm >Likewise, control of brightness would be a problem.

I think only in terms of scientific studies.  I suspect clinical use would not be really sensitive to brightness, and contrast could be rather closely set. >By the way, all of this was investigated (superficially) by SRI’s >bioengineering group about 15 years ago, perhaps longer. (That’s formerly >Stanford Research Institute). There are better algorithms for exploring the >field than just fixating on a point and hitting the space bar if you see a >"twinkling light".

Right. >It has been proposed several times since.

This program, at present, makes no attempt to measure depths of scotomata. >My personal opinion is it *would* work.  Just as I do not substitute my >home blood pressure machine for a visit to my cardiologist, I would not >expect any PC-based field test to substitute for visits to my >ophthalmologist. >But one could get an idea that there might be a scotoma lurking out there >somewhere and then go and get a *real* field test.

Who knows where the scotoma lurks?  Only The Perimeter knows. >I’ll send you some write-ups on the subject.  I don’t want to post them >here, because they are based on mostly theory (and hand-waving) and not on >real experimentation.

SRI has a strong background in handwaving?  ;-) I discussed this program with Walter Steuber, it’s author.  I couldn’t get it to work at all right, but I think it has considerable potential in som ways, though needing a great deal of improvement and changes in direction.  You might want to converse a little with this man and send him a copy of th write-ups you mention, although I would imagine many more recent writings from other sources would do him better. Ray

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