The Brien Holden Vision Institute Myopia Calculator is an online tool that enables practitioners to explain possible progression of myopia over time to their patients. It also provides a means to illustrate the beneficial effect of slowing myopic progression using available technologies.
The calculator allows input for basic patient characteristics (age, ethnicity, current prescription; Figure 1 – blue box) and provides an estimate for the progression of myopia until early adulthood. The estimate is based on evidence of progression from the literature and BHVI datasets and derived using statistical methods for the predicted outcome.
The calculator also enables visualizing the effect of controlling the speed of progression using a variety of clinically proven strategies. In order to show the possible net-gain of different strategies over time, control-rates from peer-reviewed clinical studies are applied to the predicted progression rate of the patient. The practitioner or patient can choose a strategy and then select from a range of published success rates (levels of slowing progression; Figure 1 – red box).
Figure 1: The input panel
The controlled progression data (Figure 2, green curve) assumes a constant control rate over the entire predicted timeframe. The calculator does not indicate or promise success rates of certain strategies over time. It is a ‘what-if’ tool providing an evidence based graphical way to illustrate the development of myopia and the achievable patient benefit when its progression is controlled.
As such, it is a great tool to illustrate the impact of certain levels of control on the outcome, the beneficial effect of starting to treat myopia progression early in life and the importance of compliance in order to achieve the maximum benefit over a long period.
Figure 2: Typical calculator output for a 6-year-old patient