Shorter days, cold and rains, Covid that still limits us: a little sadness is almost physiological in winter, but in those suffering from open-angle glaucoma the cold season can cause mood swings, anxiety, depression and sleep disturbances. This is what emerges from a study recently published in the journal Chronobiology International and conducted by researchers from the University of Copenhagen.
How time affects mood
The study shows that in the group affected by glaucoma in the autumn / winter period the production of melatonin increased significantly in the summer / winter comparison (summer 1.81 +/- 3.8 pg / ml; winter: 4.3 +/- 5.7 pg / ml p < 0.001), contrary to what happened in the control group in the summer / winter comparison (summer: 1.5 +/- 2.0 pg / ml; winter: 1.9 SD +/- 2.4 pg / ml p = 0.17). Significant differences were also found in specific scores on sleep quality and mood in the comparison between the glaucoma group and the control group. "This study highlights that in patients with open angle glaucoma there are seasonal differences in the production of some neurohormones, such as melatonin and cortisol, which are related to the sleep-wake rhythm, the quality of sleep and the 'mood ”, declares the professor Luciano Quaranta, former professor of Diseases of the visual apparatus of the University of Pavia and member of the board of directors of the Lombard Ophthalmology Society.
The ganglion cells of the retina
To determine these reactions are the ipRGC (intrinsically photosensitive retinal ganglion cell), that is the intrinsically photosensitive retinal ganglion cells, which are a ‘subgroup’ of retinal ganglion cells (RGC) of which glaucoma causes death. The researchers found that glaucoma patients exhibited a seasonal variation in hormone levels that was not present in healthy subjects. These neurohormonal changes may contribute to the increased risk of mood and sleep disturbances seen in patients with glaucoma. “It is likely – explains Professor Quaranta – that the loss of ipRGC leads to a greater alteration of the so-called ‘non-image forming visual functions’ in the glaucomatous subject and therefore to greater alterations in the mood due to the inappropriate perception of light as regulatory factor of the circadian rhythm “.
The ‘non-visual responses’
The intrinsically photosensitive retinal ganglion cells are crucial for promoting sleep during the night and in general for the body’s recognition of circadian rhythms. “The ipRGCs play an important role in the so-called” non-visual “responses to light which include the alignment of our internal clock to the environmental day / night cycle, the regulation of sleep-wake cycles, the pupillary reflex to light and the modulation of mood ”, continues Professor Quaranta.
Glaucoma and other degenerative diseases
Several recent studies have highlighted the progressive loss of ipRGC with aging, which worsens in neurodegenerative diseases such as Alzheimer’s and Parkinson’s. “Patients suffering from these two pathologies – declares the ophthalmologist – have 25-30% less ipRGC than healthy controls of the same age. Furthermore, protein aggregates have been observed in and around the ipRGCs of these patients and may be the cause of altered neuronal physiology. This suggests that iRGC degeneration can lead to alterations in the circadian rhythm and sleep dysfunction in neurodegenerative disorders ”.
Glaucoma and depression
Anxiety and depression are two of the psychological aspects most associated with open angle glaucoma. A meta-analysis conducted over 25 years on various ophthalmic patients revealed that as many as 25% of patients with glaucoma suffer from depression. In part, this is due to fear of visual impairment and anxiety about proper adherence to prescribed treatment regimens. “Circadian function can interfere with the quality of life of these patients. Precisely for this reason, sleep disturbances in glaucoma sufferers should be considered as part of a multidisciplinary clinical evaluation, in order to improve the quality of life, ”says the ophthalmologist. “There are other factors, such as glaucoma medications, that can affect these complex systems that make up the circadian rhythm; however, currently, no studies have reported a clear relationship between eye drops for glaucoma and sleep disturbances ”.
How to improve the quality of life
Glaucoma is a chronic disease of the elderly that can cause sufferers to fear isolation and lack of self-sufficiency, causing depression and a deterioration in the quality of life already altered even by repeated administration of glaucoma drugs during the day. and for the other diseases that the elderly often suffer from. Furthermore, at this time of the year everyone – even more so patients with glaucoma who generally tend to go out little – spend most of the days indoors where natural light is replaced by artificial light for many hours with inevitable repercussions on the ‘humor. How to improve the quality of life of the patient with glaucoma in the darkest months of the year? “By following three simple rules. In the first place – suggests the ophthalmologist – it may be useful to face this delicate moment of the year with a specialist check-up to verify the therapeutic regimen, the state of the disease and above all strengthen the doctor-patient alliance. Secondly, to help them spend the winter without getting bored and feeling penalized by imperfect vision, we take advantage of new technologies such as, for example, audio books and podcasts ”.
Fruits and vegetables
Finally, it is important to take the right quantities of fruit and vegetables because a study on Jama Ophtalmology has shown that a higher intake of nitrates thanks to the consumption of these foods is correlated with a lower risk of the onset and progression of the disease. “Broccoli, cabbage, salad, lettuce and spinach are the best carriers of nitrates, precursors of nitric oxide, one of the most important biochemical mediators in our body, capable of dissolving the bonds of platelets (between them) and white blood cells (on the walls of blood vessels) and to induce relaxation of the smooth muscle of the vessels. Since in open-angle glaucoma the increase in intraocular pressure is caused by the increase in resistance in the outflow pathways, the better the blood flows, the lower the risk of developing the disease ”, concludes Quaranta.
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