DISTORTED AND BLURRY VISION
What is astigmatism, and can it be fixed?
In the normal eye, the cornea is curved the same in the horizontal and vertical directions, like a football. When the light rays hit the cornea, they focus at a single point.
In astigmatism, the curve of the cornea is not the same in the horizontal and vertical directions. The cornea looks like a rugby ball, with a steep curve on one side and a flat surface on the other.
As a result, light rays entering the cornea do not focus at a single point, causing distorted vision.
How does one get astigmatism?
Astigmatism is a function of the beautiful and infinite variety we see in nature. We see many variations among us, including the shape and size of our eyes. We see astigmatism as a function of this variety. Sometimes, severe forms astigmatism can develop into disease states, like keratoconus, and can further complicate visual issues like a cataract.
What are some options for treating astigmatism?
How James Ball handles astigmatism treatment depends greatly on what associated conditions the patient presents and the type of treatment we plan.
With the extensive refractive surgery offered at Custom Vision Clinic, Mr Ball is also able to correct astigmatism with lens replacement surgery. We can achieve this by combining the lens replacement surgery with toric intraocular lenses or limbal relaxing incisions.
Over the last few years, both the measurement of the cornea and the calculations of toric lenses to correct astigmatism have improved. One of the greatest moves forward was the development of the Barrett formula which incorporates the effect of the posterior corneal surface on astigmatism.
Professor Graham Barrett – with whom James worked with ten years ago at the Lion’s Eye Institute in Western Australia – devised this formula. The posterior surface of the cornea can now be measured with several devices, and this is a measurement which we undertake routinely on all pre-operative cataract patients and lens replacement at the custom vision clinic.
At the Custom Vision Clinic, we have invested in the cataract module of the Pentacam imaging device to obtain this data. Also, we have invested in the latest version of the Lenstar biometry machine from Haag-Streit incorporating all of the latest software to calculate astigmatism correcting lens implants. The latest software includes the RBF-Hill software and also the Barrett formula. The Lenstar also provides us with an alignment image to ensure accurate placement of the toric lens implant inside your eye at the time of surgery.
The Custom Vision Clinic has partnered with several of the lens manufacturing companies so that we can incorporate toric astigmatism correcting lens implants into our routine cataract surgery care pathway without any additional cost to our patients.
Toric astigmatism correcting lenses are not routinely available on the NHS. At other private clinics, patients are charged an additional premium for toric astigmatism correcting lenses.