A recently published study suggests that older people with glaucoma suffer greater problems at home than during an eye test in a clinic. Is poor home lighting to blame?

When we visit our optician for an eye test, we make several assumptions. First is that they are testing our eyes in the best setting to enable an accurate diagnosis. The second is that measurements taken in the test room would be the same as if they were taken under false lighting elsewhere, in particular at home. However, this may not necessarily be the case, as previous studies have shown that some people report that their sight difficulties seem to be worse at home than would be expected from the sight test results they have been given.

The implications for people with eye conditions could be considerable, as this could affect the way in which conditions are managed. In addition, eye tests form the basis of a clinical diagnosis, and an accurate test will allow a doctor to make an early diagnosis. In some cases preventative measures can be taken to avoid or delay further deterioration.

For Glaucoma sufferers, accuracy in eye tests is critical. Glaucoma causes an increase in pressure inside the eye, damaging the optic nerve which is the main nerve facilitating sight. This damage can result in poor eyesight in one or both eyes. Regular sight tests are the primary recommendation made to Glaucoma sufferers, so that any deterioration can be picked up early on, hopefully before vision is affected. Recent research published in America’s leading clinical opthalmology journal, JAMA Opthalmology, would suggest that good lighting at home can make a real difference to the visual acuity of people with Glaucoma.

To assess the scale of the problem, researchers looked at a group of 175 people aged between 55 and 90 who took two eye tests in a four week period, one at home and one in a professional eye clinic, between 2005-2009. Of the group, 49 did not have an eye condition of any description, while 126 were registered glaucoma sufferers. The study enabled researchers to make a direct comparison of how well the group could see during the two tests. In addition, measurements were taken of how well lit each person’s home was, in order to determine whether this had an impact on results.

Results showed that the groups as a whole recorded worse results during the home test than during the one held under clinical conditions. The figures for glaucoma sufferers were of particular note: 39 fewer people per hundred could read at least three lines of an eye chart during the home test than during the clinical test, and 29 fewer per 100 could read the first two lines. It was also noted that most people’s homes had lower lighting than in the clinic. The glaucoma sufferers, on average, had lighting levels 3 to 4 times lower than levels suggested for clear vision. The researchers observed that those who had insufficient home lighting reported poorer near and distant vision, were more sensitive to changes in contrast and glare. These findings were consistent across all the glaucoma sufferers, regardless of the severity of the condition.

It is too early for the findings of the research to be verified, and the researchers are aware that the study took place among a small group of individuals under varying conditions with different examiners. A larger study over a longer period would provide more accurate findings. The researchers concluded that “vision measured in the clinic is generally better than vision measured at home, with differences mainly owing to poor home lighting. Knowledge that vision discrepancies between patient report and clinical testing may be owing to home lighting may initiate clinician-patient discussions to optimize home lighting and improve the vision of older adults in their homes.”

What is clear is that being able to see well at home is critical, especially for older people with glaucoma who have problems moving from rooms of varying darkness, and who run the risk of tripping over unsighted objects or misjudging the height of steps.

Sources:

1. The JAMA Network:
   Glaucoma Update.
2. Boots Opticians:
   Latest news.