Try It Yourself
Purcell’s retinoscopy simulator was designed for tablet sizes and above. Please view on a larger screen or device for an interactive walkthrough of the controls and features available with this simulator.
Position & Sweep
In this screen just two basic capabilities are operating. You can drag the retinoscope to position it over the patient's right eye. And you can make horizontal sweeps there, left and right. Try it. Watch the reflex. You may see an indication of the location of one of the meridians.
Angle, Weak Sphere
& Strong Sphere
In this screen the streak angle is controllable through the retinoscope sleeve. And the weak sphere dial (power) is operational. The strong sphere dial is operational, too. So you should be able to identify accurately the power of your candidate for sphere meridian.
The actual RE for this patient is:
You can compare your candidate to the actual built-in sphere power. And don't forget. In the example there is +1.50D allowance for working distance.
Power & Axis
In this screen the weak sphere dial and the cylinder power knob are both working. You can try to position the axis by working with the cylinder axis dial. And you can assess cylinder power and axis by these dials.
Now you should have something close to the built-in RE for this eye.
Autoselect or Define
This is the Retinoscopy Control Panel. The panel helps you select examples, check your answers and time your session.
Here's how you call up a case. Start in one of two ways:
1. In the Autoselect cell, select “Enter” for a random selection. Or, 2. Select an example from a defined range of power by selecting a range of powers that you want to practice on: Sphere powers, from Low to High, and Cylinder powers from None to High. Once you have chosen, your case will appear.
As you begin a case, you may want to start the timer.
The timer controls are operational in this screen, as are all of the controls. Just select the timer's start button.
To measure your progress or to compare with other students, you may want to keep a record of your success rate and completion times.
Check Your Progress
When you have completed the case, enter your findings, and check your answer.
For this introduction you can see the correct answer by selecting the Check Answer button, followed by the button that says Exact RE.
Credit for correct answers is affected by the application of standard tolerances. So, you may get credit for a correct answer even when you enter one that is slightly incorrect.
If you would like to comment on this control system, please contact us.
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Enter Refractive Error
Elapsed Time: 00:00
One or more values are not within tolerance
▼ Enter Findings ▼
To start, autoselect a case.
Or, choose power levels.
Type of Case
Choose Power Levels
Please choose all required values: