Eye power, also known as refractive error, is measured in diopters. Eye power is generated when the shape of the eye or the eye structure undergoes changes preventing the light from focusing on the retina.
Eye power once generated can be corrected with corrective lenses, such as glasses or contact lenses. To check vision loss you need to correct your vision by choosing a lens which has the same eye power.
What are the different types of eye power?
There are different types of lenses to check your eye power which mainly includes plus number lenses, minus number lenses and cylindrical number lenses.These lenses are made as per your eye power detected by your doctor during eye test.
The Plus number is also known as hyperopia and it is a type of eye power defect that could be rectified with a plus-numbered lens.
The minus number is also known as myopia, a type of eye power defect that requires a minus-numbered lens.
Cylindrical number : This is a type of eye power that requires a cylindrical lens and is used to correct astigmatism.
What do you understand about Minus power?
Minus Power : Minus power is indicated by a negative number on an eyeglass prescription. In this case the lens “diverges” light rays to focus them properly on the retina, making the distant objects appear clearer. Negative or Minus eye power suggests that the person is myopic, which means he has a blurry distance vision. This is the most common type of power which the youngsters as well as adults face today. The ongoing lifestyle and digital screen time could be considered as the prime cause behind it. In many cases it is progressive in nature wherein the minus power keeps increasing. Right Ayurvedic treatment and lifestyle changes suggested by the doctor could be the best remedy for your eyes at Dr Basu eye care Centre.
Key pointers about minus power lenses:
Some of the key pointers about minus power lens include
- The minus power lenses are concave in shape. It means they are curved inwards, which helps to spread out light rays before they reach the eye.
- Nearsightedness correction: In case of a person who is nearsighted, the eye focuses the light in front of the retina. This minus power lens helps to correct this by bending the light rays slightly further back.
- Reading the prescription: When a doctor gives an eyeglass prescription, a minus sign (-) mostly indicates a minus power lens needed to correct nearsightedness.
What do you understand by plus power ?
Plus power is indicated by a positive number on the eyeglass prescription. In such cases the lenses are thicker are thicker in the middle and thinner at the edges. In hyperopia light rays focus behind the retina instead of directly on it. These lenses are helpful in projecting light on the retina and to see near objects clearly. Plus power indicates that the person is suffering from hypermetropia or hyperopia, which means he has problems visualizing nearby objects. The plus power generally impacts the human eyes once you are in your forties because as you age, the lens in the eyes starts losing its flexibility making it difficult to change shape to focus on close objects.
Key Pointers About Plus Power Spectacles: Some of the key pointers for the plus power lenses include
- Lens Shape: In case of plus power lenses the lenses are convex (curved outward). This helps to converge the light rays and focus them in the right way on the retina.
- Prescription : A positive number on the eyeglass prescription indicates plus power lenses
- The Age Group: People with plus power are common in people above 50 often due to presbyopia, when the eye lenses start losing their flexibility.
Symptoms of Plus Power (Hyperopia):
Blurry vision
Eye strain or headaches
Squinting to see clearly
Difficulty in reading
What Does Cylindrical Power Mean?
The original shape of the eye is spherical, but when cylindrical power arises, the frontmost layer of the eye known as cornea becomes like an oblate rugby ball. This shape forces the power to be displayed only in a distinct direction called the axis. This does not mean that one’s eyes are defective; rather, it means that the eyeballs have lost their original shape and need a cylindrical number to see clearly. Individuals with a high cylindrical number (more than 3.00) may indicate a condition called keratoconus. People with more than three diopters of cylindrical power should undergo a topography test each year. This test helps prevent if they have developed keratoconus.
What Does Spherical Power Mean?
Spherical power occurs in case of correction needed to check nearsightedness or farsightedness. Here, the shape of the cornea is normal, but light does not get appropriately focused on the retina; instead, it gets focused either in front of or behind the eye.
The main symptom is that the individual sees everything he experiences
- blurry vision
- Headaches, especially after reading or using screens
- Nighttime glare or halos around lights (Avoid driving)
- Squinting to see clearly
- Watery eyes due to eye irritation
Both myopia (nearsightedness) and hyperopia (farsightedness) are types of spherical power. The spherical powers are depicted by diopters.
What Does 6/6 Mean?
6/6 (read as 6 by 6) means you have perfect vision. The “6” in the numerator stands for 6 meters, the testing distance and the exact distance for the eye test. This is the perfect vision or the ideal vision i.e. 6/6 or 20/20. This means that the person can see and read the letters which are placed 6 meters away from him. This person does not need any glasses. When the vision is 6/9 it is not considered a perfect vision and here the person will see the letters from a distance of 9 meters with help of spects which he was supposed to see from 6 meters. The person is given a minus number lens ranging from -0.50 to -1.00 diopters.
Read More: What does 6/9 & 6/12 vision means and how to cure It
Conclusion: Understanding eye power and its different types is crucial. For maintaining good eye health and correcting vision related issues starting from myopia (minus power), hyperopia (plus power), or astigmatism (cylindrical power), each type of refractive error needs suitable corrective lenses. For personalized treatment and expert advice, consulting specialists, such as those at Dr. Basu Eye Care Centre, can ensure you receive the best care for your eyes. Remember, early detection and timely correction are key to enjoying clear vision.
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