GSLS Part 6 - Dr Lynette Johns talk on corneal pain

"Invisible Pain Syndromes: Why scleral lenses do not always work"

This was a course presented by Dr Lynette Johns at GSLS yesterday.

Some introductory notes from me first...

It was standing room only, there were no tables, and I was so squished I couldn't use my laptop to take notes, so all I have is a lot of hastily scribbled notes that are now very hard to read, and I know I need to go find the course outline and make sure I didn't miss anything. For those who don't know me or my background, I want to emphasize that I have no medical background or credentials whatsoever, and I fully recognize the inadequacy of my knowledge base to report on this with complete accuracy. But the subject matter is so compelling that I just have to write about it.

I wish every single doctor treating severe dry eye and corneal pain patients could experience this talk some day. I believe that it would be seriously transformative when it comes to how they relate to corneal pain patients who do not have any dramatic clinical signs of dry eye. If they could know what Dr Johns knows before people like us walk in the door, how much suffering would be alleviated sooner!

I wish every dry eye pain patient I've ever known could experience this talk. I just think that the validation of hearing their issues so well understood from all perspectives would be therapeutic and productive of hope, which is the scarcest commodity of all in this world of corneal pain.

Finally, I want to note that, unlike most of my blog posts on GSLS, this is not exclusively reporting what I heard. I've added some links and some additional commentary for context. I also do a certain amount of ricocheting between Dr Johns' talk and my own personal commentaries for context.

Signs vs symptoms

Dr Johns started by introducing the concept of the disparity between signs and symptoms in dry eye, referencing several studies (Begley et al 2003, Nichols et al 2004, Kyei et al 2018 - the latter an odd one from Ghana with 215 students with astronomical OSDI dry eye severity scores). She went on to explain what led to Dr Perry Rosenthal's famous Pain without Stain concept and paper, likening it to "fibromyalgia of the eye". 

She gave a slide of patient quotes which I didn't jot down but they will be all to familiar to you, because they are your lived experiences. She did not hesitate to bring up the suicide connection (which I can personally attest to, incidentally, having lost numerous people over the years, and with nearly 18 years of phone calls with people who have experienced suicidal ideation due to corneal pain, and I've also written about this recently) including recently publicized ones such as the meteorologist in Detroit. Refreshingly, while she was at pains to make it clear she was not maligning elective refractive surgeries per se, she did not hesitate to engage the connection based on her long history of clinical experience with this specific connection. 

Before I go on...

Pardon me while I shout, but IT IS SO D*** REFRESHING to hear a doctor talk SENSE, FACTS, MEDICINE and SCIENCE when it comes to interpreting patients' pain - which, let's face it, really IS a valid blanket term for all these "unpleasant sensations" we experience. That is what I was feeling from the beginning to the end of this talk.

Doctors, if any of you are reading this: This area is too often treated unscientifically. Patient complaints are just treated as... complaints... in the social rather than the medical sense. And they can't be alleviated by being nice. Good bedside manner when collecting symptoms is important, but not enough, if it stops there. There is more to this business than empathy and kindness, though heaven knows we need that too! It's about seeking out the facts and exploring them scientifically like Dr Rosenthal.

The manner and kindness parts, I believe, may be critical to opening the door so that it's actually possible for you to collect qualitative and quantitative data from pain patients. Then you need to know what the data are telling you, which is part of what this talk was about.

Real pain vs exaggeration vs faking it

It was wonderful to hear such a clear articulation of the dilemmas doctors face and to hear these issues talked about dispassionately, sensibly and compellingly.

Dr Johns engaged the questions of malingering and somatic symptom disorder by explaining the DSM IV definitions of them. It's worth looking at those, so I've provided some links. In malingering, the emphasis is on what the 'ulterior motive' is - financial, avoiding work, etc. In SSD, the emphasis is more on the thought and behavior patterns associated with the symptoms.

The bottom line

Caveat: These are not Dr Johns' words! But I hope and believe that I am accurately reporting the overall framework that she was conveying:

1. A noticeable gap between signs and symptoms compels physicians to question the accuracy of the symptoms, BUT:

2. A noticeable gap between signs and symptoms is also AN ESTABLISHED FACT of ocular surface disease pathology. It is a core part of the reality of dry eye.

3. Therefore, doctors need to be careful not to dismiss symptoms as medically insignificant, even when they cannot verify the causes through standard dry eye clinical testing.

Of course, to us patients, symptoms are everything, as Drs Saldanha, Akpek, Han, Dickersin and I highlighted in our Jama Opth study published last August. This is not intended as self-advertising, but I do want that study seen and read because it matters.

The science of corneal pain

How pain without obvious causes works

With that framework in mind, Dr Johns moved on to the science of pain. I'm not going to attempt to cover that in detail... first, I don't understand it, second, detailed technical stuff is not my thing! But if you want overwhelming science, look for the TFOS DEWS II subreport on Pain and Sensation.

But in brief, she talked about nociceptors... and the sensitization process, where inflammation modifies the nociceptor responses and keeps them firing inappropriately - basically lowers the threshold for response and increases the response when that threshold is passed. She explained the physiological role for that pain response, likening it to the pain of a broken ankle compelling you to keep weight off it while it heals. 

Then she talked a little about the poorly defined concept of "chronic pain" and the altered neurophysiology behind it. She talked about the TFOS DEWS II findings on neuropathic pain, and how the activity perpetuates itself even in the absence of the actual stimulus - how it's basically a malfunction of the pain-inhibiting mechanisms: the stimuli are misunderstood. 

Examples of causes of corneal pain

  • dry eye disease
  • ... keratopathy (can't read my handwriting)
  • recurrent corneal erosions
  • refractive surgery
  • chemical burns
  • toxic kerat
  • radiation treatment
  • trigeminal neuralgia, fibromyalgia

Patient profiles for neuropathic corneal pain

Next she went on to describe patients that she would be likely to suspect for neuropathic corneal pain:

On the symptom side, typical patient reports as burning, aching, stinging, photophobia and a feeling of pressure. 

On the signs side, they would be normal. TFOS DEWS II defines normal for us, for example, OSDI <10, non-invasive TBUT of 10-11. (Ref TFOS DEWS II diagnosis subreport?)

There was more... I'll try and pick it up from the outline later.

Assessing symptoms 

Dr Johns went on to discuss the symptom assessment instruments, i.e. the little questionnaires you can fill out that collect information about your symptoms in, hopefully, a scientifically meaningful way. (A brief aside: this is something I had a great opportunity to learn more about by spending a full day with the fabulous epidemiology team - led by Fiona Stapleton - from TFOS DEWS II a few years back. Part of the team's job was to evaluate all these surveys. It was somewhat discouraging because there are SO MANY and they have been employed so inconsistently over the years that all these years of research, in symptom terms, cannot be compared apples to apples - which was of course one of the things they emphasized in their results.)

The best known of these is OSDI, which she encouraged the use of particularly because it has an environmental triggers section. She emphasized environmental triggers as a common feature in neuropathic dry eye patients, such as excessive sensitivity to temperature and to air movements. She also suggested specific (oopsie, inadvertent tongue twister) questions for doctors to ask. For example - here's a familiar one to a ton of us patients - our eyes' response to walking into a big box store with the combination of blowers and fluorescent lights. (I might be putting words in her mouth with that level of detail, but that's the bit that stuck in my memory.)

There are others, such as SPEED (which assesses type, frequency and severity of symptoms, SANDE (which has very high repeatability), and OPAS, developed at Mass Eye & Ear.

Note to self... a project on my list since the beginning of time was to get all of these surveys in one place for patients to use, but it meant tracking down the copyrights and asking permission, and I got bogged down in there somewhere. *If* the right people *happen* to ever read this and want to volunteer to help, I'd be delighted.

...Sjogrens, neuropathy, and when sclerals do/don't help?

Somewhere in there she talked about primary versus secondary Sjogrens syndrome, mentioned that neuropathies in general are common in primary Sjogrens, and that in her experience primary Sjogrens patients with corneal neuropathy have about a 50/50 chance of scleral lenses relieving pain, one of the challenges being hyperesthesia in the conjunctiva, where the scleral lens becomes too much of a stimulant itself.


Treading thinner ground here with my sketchy notes, but do want to at least highlight a few things:

She mentioned a proparacaine challenge test to see whether the dilute proparacaine attenuates peripheral pain. 

She mentioned the counterintuitive point of decreased corneal sensitivity but where the cornea is registering so much pain - that is, a numb cornea with a heightened response? similar to post herpetic neuralgia. So that brought up testing corneal sensitivity with all the conventional and new tools for that.

She mentioned confocal microscopy, which is NOT a readily available tool in optometry practices, but is being used quite a bit in neuropathic dry eye pain diagnoses. Mentioned a study by Labbe et al in IOVS, 2012. She emphasized the experience needed to interpret results, but I believe the two features she mentioned were corneal sensitivity and pain correlating with (a) nerve density and (b) nerve tortuosity.

She highlighted a study by Dieckman et al in Ophthalmology (2017 about neuropathic corneal pain. This has a really nice diagnostic flow chart (it's available at this link with the abstract).


These are not exhaustive notes, just some highlights.


  • Reducing inflammation (with the usual tools)
  • Supporting nerve regeneration... she spoke quite a bit about the use of autologous serum, and referenced a protocol (I don't have the source, sorry) for 20% 8 times a day for 4-5 months, emphasizing that this is not a quick-results process and that a slow taper off is necessary to prevent rebound (first I've heard of that and it made me prick my ears up because of the many, many, many pain patients out there basically self-managing their own care and using their doctors solely as providers of Rx). 
  • There was a study showing 8 weeks on 20% plus loteprednal, resulting in "less tortuosity" of the nerves verified on confocal.
  • Tacrolimus 0.03% for 3-6 months


Since stimulation of a hypersensitive cornea is such an issue, physical protection mechanisms were highlighted, including:

  • Soft contact lenses
  • Goggles [dry eye glasses]
  • Scleral lenses
  • Compresses
  • Plugs? (unclear)
  • Cryopreserved amniotic membrane but without the ring because it's too painful (e.g. ProKera, pop out the tissue and use that with a bandage soft lens over it)


  • Anticonvulsants e.g. Gabapentin
  • Tricyclic antidepressants e.g. nortryptyline
  • Seratonin re-update inhibitors e.g. Cymbalta
  • Carbomazepine?


  • Acupuncture?
  • Transcranial magnetic stimulation?
  • Scrambler therapy?
  • Implantable neuromodulation?

Dr. Johns' last words on this topic:

"Just because you don't see it, doesn't mean it isn't there."

Mental health 

This was mentioned earlier, during talk of topical treatments, but I wanted to call it out separately. Note that this is definitely MY amplified version of what she talked about, not her words - especially the last two paragraphs which are really just all me.

Dr Johns highlighted the all-important fact of corneal pain having substantial mental health impact on patients, and the challenges facing eye doctors attempting to relate to that in such a way as to help without harming.

Then she provided a fantastic tool: An example of SPECIFIC LANGUAGE suggestions doctors can use as they proceed down the perilous path of discussing mental health with their patients, recommending follow-up with mental health care/support, and offering assistance to find appropriate providers.

The challenge for doctors, as I see it, is that unless you really are well attuned to the pain side of dry eye and to the reasons and extent of the mental health impact (not always possible, since it's so hard for patients to share this with many of you), even broaching the subject can so easily be interpreted as being dismissive of the physical pain they are experiencing. We patients, especially if we have previous history of not having our symptoms taken seriously (for want of clinical signs), are absolutely primed to interpret your words, in conjunction with your facial expressions and body language, as one of the many variations on the theme of "It's in your head." There is no more devastating, hope-killing message you could convey to a patient in genuine pain.

And that is  one of the cruelest aspects of Pain without Stain: That the physician response so often inhibits patients from advocating for themselves effectively - across the board - with their healthcare providers, employers, and personal support systems. It's a tragedy, and it's becoming an unrecognized public health crisis. Take it from an insider who speaks frequently with patients who experience suicidal ideation. We Have A Problem. This is, in fact, a driving force behind the new fledging Dry Eye Foundation.

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1 comment
  • Hi I was a patient of Dr Lynette John’s and she fitted me to scarla lens. Then because of the pain I was having in my eyes and thought they looked good to them I was in pain. I beacame Dr Rosenthal’s patient and he said I have neuropathic pain. It’s hurts so bad. I need to find out more about pain relief for right eye that I can’t where the scarla lens in. Any suggestions please, Laurie

    Laurie Kimball on

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