You can improve your weak eyesight by eating a healthy and well balanced diet such as fish high in omega 3 fatty acids, carrots and dark leafy greens.
Taking some omega 3 supplements can also help improve your eyesight and eye power and eye health and using protective eye wear to prevent damage to your eyes can also help and wear sunglasses in the sunlight to protect your eyes from the UV rays.
You should also get plenty of sleep, get regular exercise and have regular eye exams to help keep your eyes healthy.
Having eye surgery such as Lasik eye surgery can also improve your weak eyesight or vision and eye power.
Eye power is the refractive power of the eye and is the ability of your eye to bend light rates to focus on your retina.
And having refractive errors such as nearsightedness or myopia and farsightedness also known as hyperopia occur when your eye does not focus light correctly, which leads to blurry vision.
Refractive surgery such as LASIK eye surgery can reshape your cornea and correct refractive errors and potentially reduce or eliminate the need for contact lenses or eyeglasses.
Glasses or contact lenses can also help correct refractive errors by providing you with the necessary lenses power to focus the light correctly on your retina.
Eating a balanced diet that is rich in minerals and vitamins and staying hydrated and getting enough sleep and limiting screen time can also improve your eye health.
To know your eye power also known as refractive error you will have to see an eye doctor by scheduling an eye exam.
The eye doctor or optometrist or ophthalmologist will perform some eye tests such as retinoscopy and visual acuity, which measures how well the eyes focus light and determine any necessary lens correction.
The eye doctor will perform a visual acuity test which is often done using the Snellen chart that measures your ability to see letters or symbols at a specific distance which helps to determine if you have 20/20 vision or require corrective lenses such as eyeglasses or contact lenses.
A refraction test will also be done by the eye doctor which uses a phoria or autorefractor that helps to determine the power of lenses that are needed to correct any refractive errors such as myopia also known as nearsightedness and hyperopia also known as farsightedness or astigmatism.
Another test that is done by your eye doctor for determining eye power is a retinoscopy which is a test that uses a handheld device called a retinoscope to observe your retina under a beam of light which helps to determine your eyes refractive state and the power of any lenses that may be needed to correct the vision.
An autorefractor eye test uses and automated device or autorefractor to measure the refractive error of the eye by analyzing how the light reflects off your retina and helps to determine the power and type of contacts or prescription glasses if needed.
And a visual field test is a test that measures the range of your vision and helps to identify any loss of vision or other eye conditions.
Also the numbers that you see that are written in your eye prescription under abbreviations such as SPH, OS and OD determine your eye power.
The numbers range from (+/-) 0 to 20.