Certified Ophthalmic Medical Technologist (COMT) Practice Exam

+1.00 -1.00 X 180 is an example of which kind of total (refractive) astigmatism?

1. Simple hyperopic astigmatism

2. Simple myopic astigmatism

3. Compound hyperopic astigmatism

4. Mixed astigmatism

The correct answer is: Simple hyperopic astigmatism

The prescription +1.00 -1.00 X 180 represents a specific type of total refractive astigmatism. In this case, we have a sphere power of +1.00 diopters and a cylindrical power of -1.00 diopters at an axis of 180 degrees. To determine the type of astigmatism, it's important to consider the signs of the spherical and cylindrical components. The spherical component indicates that there is hyperopia (farsightedness) present because it has a positive value. The cylindrical component, which is negative, signifies astigmatism that causes additional focusing problems, resulting in a mismatch between the different meridians of the eye. Since there is a positive spherical component combined with a negative cylindrical component, this configuration is classified as simple hyperopic astigmatism. In simple hyperopic astigmatism, one meridian is hyperopic (i.e., it requires plus power) while the other meridian is emmetropic or has no power (since effectively, it has no amount of plus or minus needed). Understanding the nature of these components allows for proper classification and treatment planning for the patient's refractive errors. The other types of astigmatism such as