Does menopause play a role in glaucoma development?

,
menopause and glaucoma development

This article on menopause and glaucoma development was originally written by Anthony Khawaja and Kian Madjed for Insight magazine.

We still don’t fully understand why some people get glaucoma and others don’t. This leads many glaucoma experts to seek out causes of high eye pressure, or to look past eye pressure at other reasons why glaucoma may develop. We know that genetics can increase a person’s chances of developing glaucoma, but it is complicated and there are other things that may also increase someone’s risk.

Why are we talking about menopause?

Overall, more men are diagnosed with glaucoma than women. So why would researchers be interested in exploring potential links between menopause and glaucoma?

If you break the number of people with glaucoma down by age group, older women and older men are quite even in terms of how likely they are to have glaucoma; it is mainly at younger ages that men seem to have a higher chance of developing glaucoma. This difference appears to even out after the average age for menopause, leading to researchers asking whether some of the female reproductive hormones may be protective against glaucoma. Does the reduction in these hormones that occurs during menopause mean that women lose the level of protection against glaucoma that they were providing? There have been many studies to explore this link.

What is the science saying?

During the 2000s, there was a notable rise in interest regarding the investigation of possible connections between female reproductive factors and glaucoma. These factors included the number of pregnancies a person had experienced, the age they had their first period, the age they went through menopause, and whether they were taking hormone replacement therapy (HRT). Lots of these studies were big population studies and, as each study showed that there may be a link, the interest was maintained and more research evolved.

It is important to note that, whilst there is a lot of research into this topic, the majority of such studies are observational. This means that they are looking for associations between menopause and glaucoma and they are not showing that one will cause the other. Most of the non-observational studies (e.g. looking at changes following an “intervention” of HRT medication) are small scale, usually involving 50-100 people. However, when you look at the results of all the studies together, there does seem to be some kind of link between menopause and glaucoma. One recent study has been presented, suggesting that if a person has a later menopause and goes on to develop glaucoma, they will develop glaucoma later. Conversely, if a person goes through menopause earlier and goes on to develop glaucoma, their glaucoma will develop at a younger age.

If the reduction of female reproductive hormones may increase the risk of glaucoma, can we do anything about it?
At the moment, the only way that we can treat glaucoma is to reduce the eye pressure. Could this research mean that there are other available treatments for women with glaucoma? There is some evidence that some HRT may be associated with lower eye pressure. There are two main types of HRT, estrogen-based HRT and estrogen and progesterone HRT. They are essentially two different blends of female hormones, and it is the estrogen-based HRT that has shown these lower eye pressure associations in the studies. The same results were not found with estrogen and progesterone HRT. In some studies, where eye pressure was taken at the time of beginning HRT, and then measured again six months to a year on, eye pressure had reduced by an average of 1-2 mmHg. These types of study give more support for a relationship between HRT and eye pressure, but overall, estrogen-based HRT reducing eye pressure a small amount is still an educated best guess based on the research.

So, should all women be starting HRT when they start their menopause?

No. The evidence is not robust enough to be making this suggestion. If a person who has glaucoma, or has other risk factors making glaucoma more likely, is about to go through menopause their eye specialist does not yet have the evidence to tell them what is best to do. The eye specialist would be making a best educated opinion based on the studies available. They may say that if a person is interested in using HRT to treat their symptoms of menopause, they may want to discuss the estrogen-based HRT as it may also aid a small reduction in eye pressure or give some protection to the optic nerve. Certainly, we do not see evidence that HRT increases the risk of glaucoma.

How big a risk is menopause likely to be then?

It is unlikely that eye specialists are going to be telling people with glaucoma that they particularly need to look out for the signs of menopause. If we get to the point where we can prove any kind of cause and effect, the effect is probably a small one – not unimportant but still small and very unlikely to be the sole cause of a person’s glaucoma. The focus should still be on monitoring the field of vision, OCT scans and the eye pressure to make sure that the pressure has been lowered enough to stabilise the disease. Using the traditional medications, laser or surgery is still going to be the best way of saving sight. It is a hot topic as it is something that hasn’t been discussed much in the past and now we are talking about it, with lots still to understand. There are still studies looking into the relationship between menopause and glaucoma, so watch this space.

What about menopause and dry eye?

Like glaucoma, dry eye is a complex disease with lots of causes, and menopause may be one of them. There are so many things that contribute to dry eye and menopause could be one of them for any individual woman. The range of causes sometimes makes dry eye difficult to treat. Often they can’t be individually identified and so we end up treating the symptoms. Causes might include meibomian glands (oil producing glands in the edge of the eye lids) not working properly, the environment, lots of screen use, etc.

Previous studies suggest there is probably a link between HRT and people reporting less dry eye. Again, it is hard to say whether this is cause and effect. If we do think there is some association between menopause and dry eye, relieving those symptoms with an estrogen-based HRT has been suggested in the literature but it isn’t a guideline or recommendation.

If you’re concerned about menopause and glaucoma development, or you would like to know more about HRT, please speak with your eye specialist about this at your next appointment. They will be best placed to advise and provide reassurance based on your individual circumstances.