Objective testing of near vision

September 9, 2010

Although near vision can never be assessed objectively, standardization between tests would be useful. However, as Dr Oliver Findl demonstrated, there is a lack of standardization between tests so that comparison of results of different near vision tests is difficult, or not possible.

High incidence of presbyopia in patients over the age of 45 years and a growing demand for spectacle independence has lead to an increasing interest in presbyopia treatments, such as multifocal intraocular lenses, so-called accommodating IOLs, different kinds of corneal treatments and lens refilling, as alternatives to wearing reading glasses. This was the message from Austria’s Oliver Findl, speaking on the last day of the ESCRS Congress in Paris.

Results of these treatments are usually evaluated using near or reading vision as main outcome parameters. Although near vision can never be assessed objectively, standardization between tests would be useful. However, there is a lack of standardization between tests so that comparison of results of different near vision tests is difficult, or not possible.

Although reading vision can never be measured objectively, it should be the aim to measure reading vision under standardized conditions. Until today, many different reading charts are in use and reading conditions vary between clinical centres and even between patients.

When presbyopic treatments are evaluated, it should be taken into account that pseudoaccomodation strongly influences the subjective accommodative response measurements, such as the push-up test as well as defocus curve testing. Additionally, macular and cortical function related to visual perception are known to play a role in extracting information from a defocused image, such as deciphering blurred optotypes from a reading chart. These effects can result in good uncorrected distance and near vision in patients, whether presbyopia was treated, or not.

There is a need for a reliable and comparable system for evaluation of reading performance to be able to follow-up patients after treatment and to compare groups receiving different treatments. This would also allow aggregation of data from different centres in multicentre trials.

Read a more detailed report on Dr Findl’s paper in OTEurope October.