| Affiliation |
(AGL) Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, Texas; Professor of Ophthalmology, Weill Cornell Medicine, New York City, New York; (SX) Class of 2023, Baylor College of Medicine, Houston, Texas |
| Description |
Summary: • Photo-oculodyniais pain precipitated by light o Both photophobia, or fear of light, and photosensitivity are possible contributing pathways • The pathway of light o Eye > retina > ganglion > optic nerve o At the optic nerve, pain and light pathways converge o Mixing of the afferent pathway of the trigeminal nerve and the afferent pathway of the optic nerve is the site of photophobia/photosensitivity • The pathway of pain o Trigeminal nerve sends signals to the thalamus, so pain is felt in the cortex • Diagnosis of exclusion o Make sure eye is normal (rule out uveitis, dry eye, optic neuritis) o Normal optic nerve o Other pain sensitive structures include the dura and subarachnoid-so hemorrhage and meningitis need to be ruled out o Key findings > Dry eye symptoms, but no dry eye signs > Wearing 2-3 pairs of sunglasses when visiting clinic > Localized in trigeminal distribution > Triggered by light o Similar pathway to migraines, with similar treatments • Treatment o Fl41 filter glasses block out specific wavelengths that cause problems o Botulinum toxin injections o Migraine medications o Greater occipital nerve block o If all else fails, stellate ganglion block |
| Transcript |
Today we're going to be talking about photo-oculodynia. And basically it's pain, what you feel in your eye that's precipitated by the light. So as you know the light, "photo", can be fear of light like "phobia", or you can just be sensitive to light, those are photosensitive. And a lot of work has been done recently trying to elucidate the pathways for both photophobia and photosensitivity, including the probable pathogenesis of photo-oculodynia. So as you know the light sensitive structures: the light comes into the eye, hits the retina, ganglion cell, and down the optic nerve. And it's here where it's an integration of the light and the pain pathways that causes the problems that we see. So around the carotid artery we have the sympathetic nervous system, we have the dura of the brain, which is a pain sensitive structure. And that means the trigeminal is going to be involved in the afferent side on the pain side. And so the mixing of the afferent pathway from the optic nerve (cranial nerve II) with the afferent pathway sensory on the trigeminal is where these photophobia/photosensitivity problems come into play. And so the trigeminal, of course, is going to send that information to the thalamus to be mediated and then you're going to be feel the pain in your cortex. So it is a trigeminal-thalamic tract. There's integration of the pain signal coordinating with the light. And so the first job of an ophthalmologist is to make sure it's not coming from your eye. So the pain sensitive structures again, trigeminal (V1) going to be innervating the cornea. So dry eye, uveitis, these are the pain sensitive things. Optic neuritis even though it's on the optic nerve, that's carried by the trigeminal so that's why the pain is with eye movement. And so when we have the combination of photophobia and photosensitivity, the first thing is to make sure the afferent pathway is intact on cranial nerve number II as well as the pre optic nerve pathway, the intraocular pathway. So both the intraocular pathway has to be normal, and the optic nerve has to be normal before you make the diagnosis of the idiopathic variety of photo-oculodynia. The patients with photo-oculodynia often have dry eye symptoms, again trigeminal-based without having very much dry eye signs. And they might come in with two or three pairs of glasses, sunglasses on because they're so sensitive to light. And even though photophobia and photosensitivity occur in patients who have optic neuritis, this is a kind of an uncommon symptom to have. It usually means that there's something wrong of a trigeminal side. In the literature the sunglass sign normally implies that the person is non-organic, but what if they don't have any vision loss and they're wearing the sunglasses? Then I don't think we should apply the sunglass sign to people whose complaint is not afferent-related on the visual side. They might actually be photophobic; they might actually be photosensitive. So before we go to photo-oculodynia you need to know about the pain sensitive structures. So the dura, subarachnoid hemorrhage, meningitis can present with patients sometimes have photo sensitivity. Anything that affects the trigeminal or the thalamic system. And so we need to make sure that eye exam is totally normal before we call it photo-oculodynia. Once we make sure the eye exam is normal, the patients of the photo-oculodynia is the diagnosis of exclusion. So you can't have anything else. You can't have any finding. The dry eye symptoms seem to predominate. The pain seems to predominate. It's localized in the trigeminal distribution, and the light is the trigger. If you have made the diagnosis clinically, based on these criteria, then we can treat. We can use tear drops to make people feel better. We can use medications including the neuropathic pain medications. We can get back use the botulinum toxin, which is the same thing we're using for migraine. And you can use all the migraine medicines as well. Interestingly migraine also has a similar pathway. Migraine patients are often photophobic and have sensitivity to light. Have to go lie down in a dark room with a cold wash cloth on your head. Migraine patients are thought to have pain mediated through this trigeminal-thalamic system. So there are clear analogies between what we call photo-oculodynia and migraine, even though they're probably not the same disorder. And because not all the wavelengths are the triggers, we tend to favor using FL41. I have no proprietary interest. But there are other filters that can be used, and it's kind of a trial-and-error process. But FL41,the rose tinted glasses is the only one that was really studied well in a clinical trial. And it has been shown to be effective and is the most likely one of benefit, so they don't have to wear the three pairs of sunglasses. They're only sensitive to very specific wavelengths. It's just a matter of finding that wave length.If botulinum toxin injections don't work, botox, we can do other injections. If the trigger point is in the greater occipital nerve, you can do a greater occipital nerve block. And for photo-oculodynia, if they fail maximal medical therapy and the easy injections, we can do a stellate ganglion block. That also was looked at in an open trial and was because of this sympathetic nervous system component, we can block here in the stellate ganglion. So photo-oculodynia: pain, eye sensitive to light. Make sure it's not the dry eye. The patients often have dry eye symptoms. Make sure the afferent system is intact. The diagnosis of exclusion, often wearing multiple pairs of sunglasses. Switch to the FL41, try the medical therapies first, try the migraine therapies first including Botox, and if all else fails, a stellate ganglion block. |
