Presbyopia and long-sightedness are not quite the same thing, as an optician friend of mine likes to tell. Long-sightedness/far-sightedness is actually known as hyperopia. See below :
Short-sighted (myopic) eyes have difficulty seeing objects clearly in the distance because the focusing power of the eye is too strong relative to the length of the eye. This results in light being focussed at a point before reaching the retina at the back of the eye. In order to see clearly, light rays must be focussed precisely on the retina before the retina converts the image from the light rays into electrical messages that are sent to the brain via the optic nerve, enabling us to "see".
In Long-sighted (hyperopic) eyes the focusing power is too weak relative to the length of the eye. Light rays are bent to meet at a point beyond the retina, making close-up vision blurred.
Astigmatism can cause vision to be blurred or distorted at any distance. This is due to the cornea being non-spherical in shape, oval like a rugby ball as opposed to round like a soccer ball, resulting in light rays being focussed at multiple points instead of at one precise point on the retina.
Presbyopia is often referred to as "vision after forty". It results from the natural ageing process that makes the lens of the eye less elastic resulting in blurred near vision, particularly blurred reading vision. Presbyopia can be treated by a process known as monovision.
Monovision is where the dominant eye is corrected for distance vision and the other eye for near vision. This removes the need for bifocal or progressive lenses and can take a few weeks of adjustment for a patient.
People with this condition can see clearly up close but not at a distance. For those who are shortsighted a number of contact lens products are now available to restore sharp, clear distance vision. Dr. Milano will prescribe a concave or "minus" lens that will redirect the light rays so that they are properly focused on the retina. more
Long-sighted individuals see better at a distance than close up and sometimes experience difficulty bringing their vision into sharp, clear focus for reading and other close-up activities. Long-sightedness can be very successfully treated with a convex or "plus" lens prescription available with a wide range of contact lens options. more
An irregularly shaped cornea that causes light images to focus on two separate points in the eye characterizes this condition. The effect is similar to the distorted reflection in a fun-house mirror. Until fairly recently, people with astigmatism were limited to glasses. But today's "toric" contact lenses can be custom made and provide enhanced visual performance and comfort. Almost anyone with astigmatism can now wear contact lenses. more
As people age, their eyes lose their ability to shift focus between far and near objects. Also called "ageing eye", this is a natural process that creates difficulty in reading small type, for example, shifting focus between the road and a car's speedometer. This condition used to be treated with prescription glasses with bifocal lenses or "reading glasses". But now there's good news for those who will be affected by presbyopia because often the condition is correctable with today's bifocal contact lenses. These lenses are individually prescribed for each person's special combination of distance and near vision, and several types of lenses are available. more
Nearsighted people over the age 40, who are accustomed to removing their glasses for close work, need to give extra thought to vision correction surgery. Because their eye gradually becomes a single-focus optical system which can view EITHER near objects OR distant objects clearly (but not both), they will probably need glasses to read if they have surgery to focus both eyes for distant objects. For some, this may be an advantage, but for others, it may not