MSer Ian Cook discovers dry eyes can be part of the picture in MS

I recently had an appointment with my optician to see if I need stronger reading glasses and whether I need to wear glasses for driving. In case you were wondering, the answer to both questions was yes.

During the eye test the optician asked me if I ever noticed my eyes were dry. I was a little surprised at this question but in truth, the answer is yes, my eyes are sometimes dry. The optician then went on to tell me something very interesting. Dry eyes, he said, can be a symptom of multiple sclerosis (MS). I told him that in my 30 years since diagnosis I had never heard this, but I would buy some eye drops the next time I visit the chemist and make sure I use them. He said that I could get a prescription for eye drops if I preferred.

An eye opener

A few days later I was reading the popular MS blog multiple-sclerosis-research.org and spotted a post by Neuro Doc Gnanapavan (that’s Dr Sharmilee Gnanapavan, a neurologist at Barts Hospital in London). The post was titled, ‘It’s in the Eyes’ and went as follows.

“I know what you’re thinking. You’re thinking that I’m going to write about optic neuritis since this is what everyone writes about. But you will be wrong. This post is about the lesser well-known portion of the eye – the conjunctiva. (The conjunctiva is the clear tissue that covers the white part of the eye and the inside of the eyelids, it provides protection and lubrication of the eye by the production of mucus and tears.)

“In a small cross-sectional study of MS patients and controls, a group of investigators from Turkey found that dry eyes are far commoner in MS than you’d expect by chance. The Schirmer test (a test of eye moisture) was below 10mm in 66.7 per cent of the participants, whilst the TBUT (tear break up time) was below 10s in 81.8 per cent of MS patients. On average the Schirmer test result was 8.45mm in MS vs 17.36mm in controls and the TBUT was 8.12s vs 13.06s in controls.” In other words, an MSer’s eyes are half as moist and tears break up nearly twice as quickly as those without the condition.

Dr Gnapavan went on, “As a result, corneal biopsies showed that the degradation of the cornea (your eye’s clear, protective outer layer) was greater in MS than in controls. It is thought that the dry eyes occur as a result of reduced corneal nerve innervation (lack of nerve support) to the eye. In addition to providing sensation to the cornea, nerves provide growth support as well. With a reduction in the corneal nerve fibre density there is an obvious reduction in the health of the cornea.” For their part the Turkish authors of the paper which Dr Dr Gnanapavan was quoting concluded by saying that “Patients with MS should be monitored for ocular surface alterations and dry eye disease.”

The eye’s window

I know that corneas matter a lot in sight, more than is generally recognised – I have a friend who has corneal problems and she is partially sighted as a result. My friend explained to me that in lay terms the cornea is like the eye’s equivalent of a car windscreen. It is literally your window on the world and blinking acts like the cornea’s windscreen wipers. Blinking keeps your eyes clean of debris with the tears acting as a lubricant to ensure that your blinking takes place in a well-lubricated environment and cleans the eye properly.

My friend does not have MS and when we spoke, I had no idea that MS could affect your corneas. Although, given the above research, it’s clear corneal damage is a potential problem and one that’s hardly surprising given that in MS, nerve damage occurs in all parts of your body, including your eyes. Just think of optic neuritis, double vision and nystagmus. They are all well recognised as MS symptoms. Now it seems dry eyes are a symptom too.

The journal Review of Optometry put the MS related dry eye problem in the following terms. It said, “Multiple sclerosis is a demyelinating disease that can lead to severe dry eye. In MS, poor corneal sensory impulse conduction can result in insufficient tear production, and lagophthalmos-associated DED (dry eye disease) can occur due to poor motor control. These patients may have limited ability to instil drops and perform lid hygiene properly, thus, punctal plugs, humidifiers and in-office blepharitis therapies may be crucial.”

Punctal plug

A punctal plug, in casge you are wondering, is a tiny medical device that sits in the tear ducts in the eyes to help prevent tears draining away, keeping the eyes moist. Punctal plugs are usually inserted by doctors or ophthalmologists.  I have no idea what is meant by in-office blepharitis therapies and little desire to find out, although I do know that blepharitis is where the edges of your eyelids become red and swollen. The good news is I don’t have blepharitis.

Fortunately, the optician told me that my dry eye problem is not that serious. And although I have noticed my eyes do get a bit dry occasionally, that’s all.  However, based on his advice I have started to use eye drops on a regular basis. They are cheap, easy to obtain and I have found them highly effective. I will try to get them on prescription next time I see my GP.

I suppose my take-away message based on the optician’s visit is to keep my eyes moist and to get eye drops on prescription. My message to other MSers would be to ask your optician at your next visit: “Do I have dry eyes?”