Over the years, many different studies have corroborated with each other in confirming that women require glasses or contact lenses for reading earlier than men.
However, the reason for this has never been confirmed, until now, thanks to a new study published in Investigative Ophthalmology & Visual Science.
The experts, led by A Hickenbotham, revealed that gender difference is caused by factors other than focusing ability, such as arm length or preferred reading distance, which they said should be considered when prescribing reading glasses or contact lenses.
The evidence was compiled by performing meta-analysis using nine cross-sectional studies to compare the prevalence and magnitude of presbyopia among men and women, and subdividing the analysis to determine what differences in presbyopia might exist between genders.
Although the results of a subgroup of studies showed that there was no significant gender-related difference in the eye's ability to focus clearly on objects at near distances, the overall analysis provided evidence that women have a need for higher power reading glasses or bifocals than men of an equivalent age.
According to the researchers, this discrepancy is likely due to differences in preferred reading distances or arm length as women tend to hold reading materials closer than men do.
Hickenbotham said the results could impact global vision care in a number of different ways.
"The findings reinforce the need for presbyopia correction programs for women - a group that often has greater unmet vision needs in developing countries. It also points out that presbyopia is a multi-factorial problem and requires solutions that are tailored to each individual," the expert added.
Although the researchers urged clinicians to do more than measure the eye's ability to focus when diagnosing presbyopia, they also suggest more carefully performed studies be conducted that better isolate and measure the various factors that contribute to its development.