What is 'Astigmatism'?
' Astigmatism' is a condition that is caused by an irregularly shaped cornea or an irregularly shaped lens. In
Astigmatism, the unequal power in different meridians causes rays of light to form a distorted line instead of focusing on a point. This results in the blurring of both distant and near vision.
What are the causes of Astigmatism?
- Curvature astigmatism
- Disease of the cornea resulting in its deformity; extreme example of this is seen in conical cornea eg: keratoconus
- Trauma to the eye involving cornea
What are the symptoms of Astigmatism?
- A point of light appears tailed off and a line, which consists of series of points, appears as a succession of strokes fused into a blurred image.
- Eye-strain
- Headaches
- Reflex nervous disturbances such as dizziness, neurasthenia, irritability and fatigue.
What are the treatments available to correct Astigmatism?
The remedies for
astigmatism include the use of :
- Toric glasses
- Semi-soft contact lenses/rigid gas permeable contact lenses
- Laser surgery for Astigmatism - Lasik & Custom LASIK
- Phakic Intra Ocular Lens – Toric ICL & Toric Verisyse Phakic IntraOcular lens
- Refractive Lensectomy - Toric Intra Ocular Lens Implantation
Toric glasses
Toric spectacle lenses have two prescription powers; one to correct long or short-sight and the other to correct
astigmatism. The two lenses lie perpendicular to each other and the spectacle lens has different or varying thickness across the lens surface.
Contact lenses – Soft Toric & Gas Permeable
Soft Toric lenses
Soft Toric lenses have twin power that is possible due to the different curvatures at different angles (one for
astigmatism, the other for either myopia or
hyperopia). Some soft toric lenses also have a mechanism to keep the
contact lens relatively stable on the eye. This prevents movement of the lenses when you blink or look around. Stability of the toric
contact lenses is necessary for steady vision.
In the astigmatic LASIK procedure,
- Your doctor first creates a thin protective flap of corneal tissue using an instrument called the Microkeratome/blade-free femtosecond laser procedure (Intralase).
- He gently lifts this flap, exposing the deeper corneal layers.
- Then he uses an Excimer laser to remove tissue from the portion of the cornea in the steeper axis preferentially.
- This focuses light back on to the retina by decreasing the irregularity in the various meridia.
- He gently replaces the protective flap, where it heals naturally and securely
This procedure is quick painless and in most cases you can return to your normal activities very quickly usually within hours.