A new study in Russian glaucoma patients reported a strong association between the level of retinal ganglion cell loss and the severity of symptoms of depression. The loss of ganglion cells that occurs as a result of glaucoma impairs the perception of light, resulting in decreased visual quality. This research Affective Disorder Journal.
Glaucoma is a series of eye diseases that damage the optic nerve, which sends visual information from the eye to the brain. Increased pressure within the eye, known as intraocular pressure, is often associated with this damage. Left untreated, glaucoma can lead to vision loss and, in severe cases, permanent blindness.
Retinal ganglion cells are an important part of the optic nerve. These are neurons located in the innermost layer of the retina that receive visual input, convert it into nerve impulses, and transmit it through the optic nerve head to the brain. In glaucoma, increased intraocular pressure creates mechanical stress on these cells, which can lead to cell degeneration and loss.
Sunlight is important for sleep and mood. Studies have found that people with glaucoma are more likely to experience mood changes and cognitive impairment. A 2021 study in Mexico reported that people with glaucoma had 10 times higher rates of depressive symptoms than the general population.
Study author Dennis Gubin and colleagues wanted to determine whether the increased risk of depression in glaucoma patients was due to loss of retinal ganglion cells. They used a noninvasive imaging technique called optical coherence tomography to capture detailed images of the retina. They also used a diagnostic test called pattern electroretinography to assess the electrical response of the retina to visual stimuli, particularly pattern stimuli such as checkered patterns, that is, retinal ganglion cell activity.
The study involved 115 patients diagnosed with glaucoma. They were required to have good visual acuity with or without correction, clear ocular lenses, and no lesions in the macular region of the retina.
Participants were assessed for symptoms of depression, preferred sleep patterns, and eye health. Researchers assessed retinal ganglion cell damage, the function of these cells, intraocular pressure, and other factors. They also analyzed saliva samples and genetic information.
The results showed that the greater the retinal ganglion cell damage and the more advanced the glaucoma, the more severe the symptoms of depression. Participants with more severe depressive symptoms had greater damage to retinal ganglion cells and decreased function of these cells. Depressive symptoms were also associated with sleep patterns, sleep duration, and age, regardless of gender.
Analysis of saliva samples and genetic information did not show a direct association between the severity of symptoms of depression and melatonin levels or genetic variation. However, patients with certain genetic mutations and advanced glaucoma tended to have more severe depressive symptoms.
The researchers concluded that progressive loss of retinal ganglion cells is associated with depression scores, especially when overall loss exceeds 15%. This study suggests that loss of these cells in advanced glaucoma may affect non-visual processes related to light sensitivity, leading to mood disorders.
Although this study provides insight into the relationship between eye health and depression, it also has some limitations. The study design cannot determine causation. In addition, the researchers did not consider the participants’ history of mood disorders, so it remains unclear whether the symptoms of depression developed as the glaucoma progressed, or whether they were present before the illness began.
the study, “Depression scores are associated with loss of retinal ganglion cells” was written by Denis Gubin, Vladimir Neroev, Tatyana Malyshevskaya, Sergei Kolomechuk, Jermaine Kornelissen, Natalia Yuzakova, Anastasia Vlasova and Dietmar Weinert.