Today, the scientific community is equipped with tools and techniques for investigating a range of diseases and medical conditions, including those for which no cure has yet been discovered. One such disease is glaucoma, which affects more than 60 million people globally. The following three recently published studies represent some of the latest findings in glaucoma research.
Migraines may be a risk factor for open-angle glaucoma among certain patients
Some forms of glaucoma can cause headaches. According to the BrightFocus Foundation, this is primarily true of acute cases of glaucoma, including the angle-closure and neovascular forms of the disease. Additionally, the National Headache Foundation suggests people experiencing headaches, foggy vision and haloed lights often mistake these as symptoms of a migraine, when they are symptoms of glaucoma.
In addition, people under 50 years of age affected by migraine disorders may have an increased risk of developing open-angle glaucoma (OAG). This finding was the result of a population-based cohort study conducted by researchers from the ophthalmology departments of the National Taiwan University College of Medicine and National Taiwan University Hospital. The research was published in February 2019 in BMC Ophthalmology.
The researchers examined data on more than 17,000 patients diagnosed with migraine during a 10-year period from January 2000 to December 2010. When the data was adjusted for glaucoma risk factors and comorbidities, the risk of developing OAG among migraine patients was not statistically significant. However, migraine patients who experienced no comorbidities were 1.68 times more likely to develop OAG than the control group. The data also showed an association between migraine and OAG among patients under the age of 50 years. While this study does not conclusively show migraines are a risk factor for OAG, it is an interesting finding in the field of glaucoma research.
Glaucoma can affect reading performance, even in its early stages
Glaucoma is often called the “silent thief of sight” because of its asymptomatic nature in its earliest stages. For those people who don’t see an ophthalmologist on a routine basis, this can mean the disease is not discovered until their vision is significantly — and irreversibly — damaged. In most cases, glaucoma first affects peripheral vision and gradually advances until the patient maintains only a small portion of central vision. Without treatment, the disease causes total blindness.
Because central vision is typically the last part of vision affected by glaucoma and central/near-central vision is crucial for reading, some people assume reading isn’t affected by glaucoma until the advanced stages of the disease. However, a study published in January 2019 Optometry and Vision Science by researchers from the University of Turin suggests even people with early stage glaucoma struggle with reading ability compared to people without glaucoma.
The study involved 140 people: 80 with early stage or moderate cases of primary open-angle glaucoma (POAG) and 60 controls with healthy eyes. The researchers used the Radner Reading Chart to test the subjects’ reading performance. Interestingly, differences in visual acuity were negligible between the two groups. However, the POAG patients made more mistakes and read more slowly than the control subjects. Despite the fact the POAG patients read words in a larger print size than the control subjects, the POAG patients still read at an average of 27 words per minute fewer than the control group. The scientists involved in the study suggested this reduced reading ability may be attributed to the loss of retinal ganglion cells and disruption of the magnocellular visual pathway.
There may be a connection between glaucoma and early cataract surgery for infants
The likelihood of developing glaucoma generally increases with age. Naturally, there are exceptions to the rule, and while rare, childhood glaucoma can occur. When it does, it most often occurs in the form of primary congenital glaucoma, which is usually present from birth, can be genetic and typically results from incorrect development of the eye’s internal structures. In other cases, children are affected by secondary glaucoma, which is a form of the disease caused by the presence of another disease or medical condition.
Recent research has identified an increase in the likelihood of secondary glaucoma development in infants. The study was published in 2019 in the Journal of Pediatric Ophthalmology and Strabismus by researchers from the NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of Ophthalmology, as well as the University of Freiburg. The researchers noted early intervention cataract surgery in infants was associated with a higher incidence of glaucoma.
The research analyzed data from 111 child patients who received cataract surgery. Among the patients were infants who received surgery at 48 days or younger (early intervention), and those infants who underwent surgery after 48 days of life (later intervention). The patients were divided into two subgroups: those with isolated cataract and those with concomitant microphthalmia, microcornea or persistent fetal vasculature (MMP). The research revealed early intervention did not yield improved visual outcomes in the subgroups.
Glaucoma occurred more frequently in patients with MMP (28 percent), and more often following early rather than late intervention (75 percent vs 6 percent). Among patients with isolated cataract, 15 percent developed glaucoma, more frequently after early rather than later intervention (42 percent vs 11 percent). Altogether, three-quarters of infants who received early intervention cataract surgery developed glaucoma. These findings suggested to the researchers that later intervention for cataract, especially in infants with MMP, is a better option.