Confused about reliability of visual fields tests results

[Iona57]

Hello everyone,I'm feeling confused about how visual fields tests relate to real life experience of visual changes. I'm wondering how to communicate with consultants etc if what I experience, and what their tests say, don't match up.

Today at my glaucoma clinic appointment I did a visual fields test and was told there was more sight loss in the lower half of my right visual field. I had cataract and Hydrus stent op on 1 Dec 2022. I have normal tension glaucoma and pressure was 14 today. But because of this further loss of vision Consultant wants to bring pressures down so had put me back on dorzolamide. Which I feel relieved about.

Now the thing is, back in January I became pretty sure that this blind area below my right eye had got bigger quite suddenly, and that maybe the pressure needed to be brought down. I was seen at Eye Casualty on 16 Jan. However they thought visual fields test was ok, and put sight loss down to temporary blurring due to some retinal swelling ( cystoid macular edema). They put me on steroid and anti inflammatory drops. I was not convinced that was the whole story. I think I can tell the difference between blurred vision and a blind area!

Because of today's visual fields test I feel vindicated that I was right all along . The edema is better but blind patch is still worse. But I feel a bit despairing, in that some sight might have been saved if my experience had been taken seriously, and I had been put on drops four weeks ago.

But why didn't the Visual fields test in Jan show this up? Is there a time lag between experiencing vision loss and it developing sufficiently to show up on a test?

Any experiences or comments would be much appreciated, thank you

[PBX142]

When you say that they thought the visual fields were OK, you mean they looked at the visual field result done at the time, compared it to the previous one and said it was no worse and there was no progression?

[Iona57 in reply to PBX142]

Yes, that's right.

[PBX142 in reply to Iona57]

I can only talk about my experience. My last VF test was several weeks ago. I felt like you that my sight had got worse, ie more of a black patch than before. Both my ophthalmologist and somebody who works with her said that the VF loss remained the same and if anything was slightly better, ie there was no progression. BUT I have been keeping records of everything - which we are all legally entitled to have - and when I got home, and looked at the paper VFS from last time and the time before, this one WAS worse. Not much - but I could see the difference. So I am taking it up with my ophtho when I go back in a few weeks. I think she is very good but SO stretched because of the wretched NHS mess that I suspect she isn't looking as carefully as she might. I hate to even think that - but it's my eyes, so I have to. I would strongly recommend you ask for copies and then you can take more responsibility and not just depend on specialists. They do their best, I'm sure, but nobody is invincible, especially at this time.

[Iona57]

Thank you so much for your reply! Its so helpful to know you have had a similar experience. I also was told that there was no change in January and that 'if anything ' it was better than the previous test.I'll take encouragement from you and be persistent about getting copies of the tests. I've had the reaction that there isn't an easy way to forward copies, but I'll be more pushy!

[PBX142 in reply to Iona57]

I've resigned myself to being a nuisance! We need to be pushy. I had to ask different people before finally getting someone who could email me my tests. I'm going to take the two VF pieces of paper with me on my next visit and may be officially labelled Miss Difficult but what price our eye sight?! Nobody cares like you do about your vision. So go for it, Princess Pushy!

[Iona57]

Princess Pushy! I like that! But as you mentioned earlier, we do have a right to have access to our health record. So if they have a problem with that, they need to sort out their systems, not make us feel ' difficult '! See, I'm getting the hang of this already! 😊Good luck in your next visit!

[Hidden]

Well, you Pushy Princesses have cheered me up after receiving the following, when I inquired if I was going to receive a report following my tests on 27th. Jan.

"Mr Y requested for this fields test; would you be able to ask him to do a medisoft letter to the patient. I know these usually don’t get reported on but could he please do a letter for this patient 😊" This is from one ophthalmology secretary to another. Does the tone of the memo suggest I'm from the Pushy Princess gang?

Like you both, I want to be involved in the future of my health & wellbeing. I wish to be a responsible driver. In my work role, I drive others, so want to know my sight is more than satisfactory.

Thank - you for pointing out that the VF tests print outs should be available. Anyone know what a medisoft letter is? No rude responses!

[Iona57 in reply to Hidden]

According to Google, if I understand correctly, Medisoft is a leading computer records system for opthalmology, used by many hospitals. It stores records and can generate letters..aha! So I could try name dropping into the conversation with the consultant or whoever, ,' Well, it should be easy to generate a letter with a copy of my visual fields test via Medisoft....'😁

Encouraging to hear that your opthalmology Dept is taking your request in its stride.

[Beecalmed]

Hi Iona57,

I find this very interesting. Is your vision loss central? I’ve had a similar experience in that I have detected vision loss that hasn’t been detected on a visual field test. In fact initially before diagnosis I had vision loss that didn’t show on a field test for over a year and so was dismissed by one optician, before I was eventually referred by another optician, and glaucoma in both eyes and vision loss in one formally diagnosed.

I was diagnosed with POAG but as I’ve had progression on reduced/normal IOPs I’m now suspected NTG and my target IOP is low teens or lower. Could it be an NTG thing? My visual loss is paracentral so close to the focal point so I’m acutely aware of it. I Initial central loss is more usual in NTG. Could that have a bearing? That central vision neurons are more sensitive so we detect change earlier than if it was peripheral?

When I’ve debated what I see with my glaucoma specialist optician and my consultant (not for very long, obviously, with my very busy consultant ) they have explained that when we do field tests you can just have a bad day and randomly miss lights but the computer algorithms look for patterns that suggest a problem and potential glaucoma. Sometimes you need to have a series of fields regularly along with OCT scans to check if there’s really something changing or to start showing significant changes on the fields.

But like you I’m convinced I see my progression long before it shows on the scans or fields. I don’t know why this is either. One thought is some of us are just more visually aware than average. I trained as a visual artist and photographer for years and consequently I’ve assumed that my brain is highly tuned into any visual changes in my sight. Certainly years of being trained to “see” and not just “look at” the world probably trained my brain to notice things. Certainly my brain looks for pattern in the world and doesn’t just process visual information.

I feel a bit sorry for my consultant who is very patient with me when I’ve insisted there’s visual loss progression. 🤔 I think he thinks blimey who is the expert on glaucoma here? I just consider that I’m the specialist where my eyes are concerned, as only I look through them and actually see what I see. 😉

On a positive note I am being checked regularly so any change will be picked up fairly quickly I hope. 🤞🏻

[Iona57 in reply to Beecalmed]

Hi Becalmed, thank you for your very interesting and helpful reply. I didn't know about the computer algorithm.Yes, I have normal tension glaucoma.

Pressure at diagnosis was 20. It's now 14 but the drops should lower it further. The patch of vision loss I'm particularly aware of is a line of blurring just below the centre of my visual field, If I look at the centre of my apps page on my mobile phone with just my right eye, I can't see the bottom row of icons ( 6th row) and can only see part of the 5th row. The icon immediately above my focal point is completely blanked out, and there is considerable blurring down the left side.

From what you say, it seems a good plan to have frequent visual fields tests if it seems as though sight is deteriorating. This should give a better idea of when sight loss seems to be part of a pattern, and when it is a one- off bad day. How frequently are you having VF tests?

[Beecalmed in reply to Iona57]

Hi Iona57! Okay so my history is rather more unusual to the majority of glaucoma sufferers as my vision loss was missed by an optician despite regular annual checks for years and despite a family history of glaucoma. Not usual; I was just very unlucky.

Consequently I found and started seeing my current optician and glaucoma specialist (who thankfully referred me on my first my appointment) every 6 mths and we’re compiling a history of fields and OCTs to spot any changes. I get time to discuss my results in detail and he reassured me that he’ll spot anything of concern.

My hospital consultant is very good and an excellent surgeon but I am acutely aware of the pressure and limited resources he and his team are working under, so I felt £16 direct debit a month was a good investment in order to have back up checks and help maintain my sight and to be my own advocate. I can’t afford any slip ups now and my early missed diagnosis means I have lost some faith in the system I think.

My vision loss means that if I close my left eye when I’m reading I see the word I focus on to read, but have lost the preceding 3 words and the 2-3 lines above it. So similar to yours but above rather than below the focal point. The jokers amongst would say “well don’t close your left eye then! Problem solved!”, but I squint in bright light and automatically close my left eye slightly. I live in a very bright sunny house so my left eye is closed often. So my solution is to wear reactolite lenses which helps me not squint and means my eye loss is less noticeable. If it’s less noticeable then it’s easier for me not to be reminded of it every day and get on with my life.

Yes try to get regular checks. 6 months is optimal. Too frequent and change won’t be obvious, too far apart and they’ll be playing catch up if you have a fast moving progression. Fields tests are pretty sensitive to change. You could ensure that they are using a field test that checks the central area of vision in detail. The standard field test is focussed on spotting peripheral loss and may miss the detail of central loss. Also make sure you are getting fairly regular OCT nerve scans as this with the field test will show any thinning of nerve density in certain areas. Lastly you could ask about retinal bleeds and notches in the rim. My retinal bleeds are in the area where the vision loss is occurring and as I said a bleed is an early warning alert of possible vision loss in that area.

Like you I’m also on dorzolamide, twice a day and bimatoprost once a day. 👍🏻

[Iona57 in reply to Beecalmed]

Hi Beecalmed,I'm sorry to hear about the delays in your glaucoma diagnosis but glad you have better support now.

Thanks to encouragement of you and other responders I've taken action, and asked the (private) consultant' s secretary to send me copies of visual fields tests on file, and I got two sent almost straight away, from Aug and Nov last year. I also took advantage of the new £10 a month subscription to my optician, and had a free full VF test yesterday. I have pored over the print out and can see clearly where things have changed . I also note that readings can go down and then up again. It still doesn't entirely tally with my experience of my vision though!

Anyway, I feel a lot better having seen the results for myself. It feels much less confusing and anxiety making than just going by the consultant generalising that things have changed, or they haven't changed, or even saying that some parts are worse and some better!

All the best,

Iona

[Beecalmed]

Well done you! Being your own advocate can be very empowering. Sometimes just having more information and increased understanding can relieve some anxiety and you feel you are at least doing something positive for your health.

Keep us posted on developments. I have my hospital check end March so I’ll do the same. 👍🏻

[Iona57 in reply to Beecalmed]

Thanks!😸