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 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.
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.
Further information about astigmatism
MORE USEFUL INFORMATION
Read more about laser eye surgery
New refractive surgery guidelines from The Royal College of Ophthalmologists, together with patient information on Laser Vision Correction, Phakic Intraocular Lens Implantation, Refractive Lens Exchange and a Checklist for patients will be published in April 2017. Click here for more information
Take this checklist to your consultation with your refractive surgeon performing the procedure. Discuss each item with your surgeon to help you make the decision that is right for you before having
refractive surgery. Click here for more information
The Royal College of Ophthalmologists’ Laser Vision Correction Patient Information booklet (PDF). Click here for more information
SMILE corrects myopia and astigmatism, or a combination of both refractive errors with only a very small incision at the corneal surface. This high-precision procedure is the latest development in the refractive laser treatments. Includes videos, treatment steps, and questions and answers.
Click here for more information
LASIK treats refractive errors by folding away the top layer of the eye and re-shaping tissue underneath. If a femtosecond laser is used, this type of procedure is called Femto-LASIK. Includes videos, treatment steps and questions and answers. Click here for more information
PRK/LASEK procedures remove a thin cell layer from the top of the eye so the laser can reshape the underlying cornea. This surgery may be an option for those who are not eligible for LASIK or those who look for the most economic option for refractive laser surgery. Includes videos, treatment steps, and questions and answers. Click here for more information
About the author
Mr James Ball | Consultant Ophthalmic Surgeon
MA (Cantab) MB BChir FRCOphth CertLRS
I am a Consultant Ophthalmic Surgeon at Custom Vision Clinic, St James’s University Hospital, and Nuffield Hospital. My major interest is in refractive surgery and finding the best treatment suitable for each patient.