Effects of refractive power on quantification using ultra-wi
Ultra-widefiled (UWF) retinal images include significant distortion when they are projected onto a 2-D surface for viewing. The purpose of this study is to investigate the effects of refractive power on retinal area measurements (quantification) using UWF retinal imaging.

A prospective, interventional study comprised 50 healthy eyes. UWF images were acquired first without the use of a soft contact lens (CL) and then repeated with six CLs (+?9D, +6D, +3D, -3D, -6D, and -9D). Using stereographically projected UWF images, the optic disc was outlined by 15–17 points and quantified in metric units. The subjects were divided into three groups according to axial length:
Group A (22–24 mm),
Group B (24–26 mm), and
Group C (more than 26 mm).

The study population was 6, 28, and 16 eyes in each group.

--Overall changes for the measured area were not significantly different in the whole study population.

--Group C had a larger proportion of magnification effects compared to Groups A and B (50.0%, 0%, and 3.6 %).

--Measured area with plus lenses was significantly higher in Group C.

Finally, when using UWF images, the use of CLs can affect the quantification of eyes with long axial duration. When assessing the area of long eyes, ophthalmologists should take refractive error into account.

Source: https://bmcophthalmol.biomedcentral.com/articles/10.1186/s12886-021-01900-y