Lenses For Long Sight – Hyperopia
Sometimes the eyeball is too short and the light is focussed to far behind the retina, again resulting in blurred vision in far space and particularly when looking at close objects and reading. This is called hyperopia.
Depending upon the degree of hyperopia near objects are blurry or harder to focus upon. In higher degrees of hyperopia objects in far space may also be blurry.
Lenses to correct hyperopia are thicker in the middle than at the edges. In higher prescriptions the lenses can be particularly thick, heavy and unattractive. There are various ways to improve the appearance and minimise the weight of the lenses. There are a number of ways to avoid this.
Tips to reduce the weight and thickness of lenses for hyperopia
- Choosing a small frame will help minimise the centre thickness and weight of the lenses.
- Lenses with a higher “refractive index” are thinner and lighter for the same power.
- Aspheric lenses flatten out to the edges and so are thinner in the middle and lighter for a particular edge thickness. This is beneficial because a minimum edge thickness is required so that the lenses do not chip at the edges.
- Anti-reflection coatings improve the appearance of the lenses and your vision through them but cutting down reflections from the lens surfaces.