Abstract
Purpose :
To analyze whether any type of visual adaptation induced by Bangerter Filters (BF) exists, beyond changes in the blur perception, in terms of Visual Acuity (VA) measured with the Freiburg VA test.
Methods :
25 young healthy adults were enrolled in the experiment, 18 females and 7 males (mean age: 26.2±2.0 years). VA was measured with the Freiburg test at 4 metres, C-Landolt optotype during 0.3 s of exposure time, 4 orientations and 30 repetitions. The BFs (density 0.6) were mounted on top of neutral spectacles. The VA was retrieved at four time points: natural viewing conditions before wearing BF (AV1); immediately after the incorporation of BF (AV2); after 40 min of vision through BF (AV3); and finally, right after returning to natural vision without BF (AV4). A control group underwent the same experimental procedure under natural vision, without filters. Objective refraction and keratometry values were also assessed before and after the use of the BFs. Regression models were used to fit the variables before and after BF use with statistical software.
Results :
The Shapiro-Wilk test yielded a normal distribution for the VA values, although the parameters describing the distributions slightly changed among the 4 measurements. A statistically significant (paired T-student test) increase of 16.7% in VA was found after 40 minutes of vision through the BFs. In contrast, the average VA in the control group exhibited no change with time. The values of objective refraction and keratometry remained constant before and after the use of BFs.
Conclusions :
A statistically significant increase in VA was measured after 40 min of continuous vision through BFs, with changes neither in refraction nor in ocular biometry. The results obtained from the control group showed that the VA improvement could not be credited to a learning effect. The VA improvement obtained in the experiment shows a quantitative enhancement in vision after an adaptation time.
This is a 2021 ARVO Annual Meeting abstract.