## How to identify Refractive Diagnosis of a Spectacle Prescription?

Identifying refractive diagnoses is very easy. Just you need to know the basic rules to identify a refractive diagnosis. There are a few simple steps given below to identify the refractive diagnosis.

At first, you need to look at signs of spherical power & cylindrical power along with spherical and cylindrical power values. If you want to do Spectacle prescription transposition to re-confirm - you should...

If spherical power is Zero or Plano & cylindrical power has a plus sign - This is called **Simple hypermetropic astigmatism**.

Example:

1. Sph 0.00 / Cyl +0.75 Axis 180 or any axis.

2. Sph 0.00 / Cyl +2.75 Axis 90 or any axis.

If spherical power value is with plus sign & cylindrical power value is with a minus sign with same spherical and cylindrical power values - Again this is called as **Simple hypermetropic astigmatism**.

Example:

1. Sph +1.75 / Cyl -1.75 Axis 180 or any axis.

2. Sph +0.25 / Cyl -0.25 Axis 90 or any axis.

If spherical power is Zero or Plano & cylindrical power has a minus sign - This is called **Simple myopic astigmatism**.

Example:

1. Sph 0.00 / Cyl -1.00 Axis 180 or any axis.

2. Sph 0.00 / Cyl -3.25 Axis 70 or any axis.

If spherical power value is with minus sign & cylindrical power value is with plus sign with same spherical and cylindrical power values - Again this is called as **Simple myopic astigmatism**.

Example:

1. Sph -1.25 / Cyl +1.25 Axis 170 or any axis.

2. Sph -2.25 / Cyl +2.25 Axis 100 or any axis.

Till here you have learned about simple hypermetropic or myopic astigmatism.

If spherical power value is with plus sign & cylindrical power value is also with plus sign with any power values - This is called as **Compound hypermetropic astigmatism**.

Example:

1. Sph +0.50 / Cyl +0.75 Axis 180 or any axis.

2. Sph +3.00 / Cyl +0.25 Axis 60 or any axis.

If spherical power value is with plus sign & cylindrical power value is with a minus sign but cylindrical power value should be lesser than spherical power values - Again this is called as **Compound hypermetropic astigmatism**.

Example:

1. Sph +3.50 / Cyl -1.75 Axis 160 or any axis.

2. Sph +3.00 / Cyl -0.25 Axis 80 or any axis.

If spherical power value is with minus sign & cylindrical power value is also with a minus sign with any power values - This is called as **Compound myopic astigmatism**.

Example:

1. Sph -1.50 / Cyl -1.75 Axis 50 or any axis.

2. Sph -4.00 / Cyl -0.50 Axis 130 or any axis.

If spherical power value is with minus sign & cylindrical power value is with a plus sign but cylindrical power value should be lesser than spherical power values - Again this is called as **Compound myopic astigmatism**.

Example:

1. Sph -3.50 / Cyl +0.75 Axis 10 or any axis.

2. Sph -5.00 / Cyl +2.25 Axis 80 or any axis.

Till here you have learned about compound hypermetropic or myopic astigmatism.

Now I am going to tell you about mixed astigmatism. So, you need to be very careful while looking at the spectacle prescription and writing a refractive diagnosis.

If spherical power value is with plus sign & cylindrical power value is with a minus sign but cylindrical power value should be more then spherical power values - This is called as **Mixed astigmatism**.

Example:

1. Sph +0.50 / Cyl -0.75 Axis 10 or any axis.

2. Sph +1.00 / Cyl -3.25 Axis 80 or any axis.

If spherical power value is with minus sign & cylindrical power value is with plus sign but cylindrical power value should be more then spherical power values - This is called as **Mixed astigmatism**.

Example:

1. Sph -1.50 / Cyl +2.75 Axis 100 or any axis.

2. Sph -0.25 / Cyl +1.25 Axis 140 or any axis.

Hope you have learned about refractive diagnosis very well.

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