Q: I am a 34 years old professional who has to work on the computer for at least 12 hours a day. My refractive power is LE Spherical -1.25, cyl -0.75 Axis 180 and RE Spherical -1.25, cyl -0.75 and Axis 10. I have been using a soft toric lens for the past 5 months and never found them comfortable. I have heard about hard gas permeable (HGP) lens or rigid gas permeable (RGP) lens. Please suggest the appropriate lens for astigmatism in terms of visual acuity as I was experiencing blurriness, dryness and redness due to soft toric lens.

A:. Your lens power with myopia and astigmatism is not too bad and you may be able to do close work even without glasses or contact lenses if it is not giving you headaches due to eyestrain. If you wish to wear contact lenses, hard gas permeable contact lenses are much better, cheaper, and easier to maintain and also correct astigmatism better than soft lenses. Cornea, the anterior transparent part of the eye, does not have any blood vessels for clarity reasons, to supply Oxygen and release carbon dioxide, which it does directly to atmosphere. If you wear contact lenses, it reduces this gas exchange to the cornea. Soft contact lenses (CL) have a diameter of about 13 mm, cornea has diameter of about 11 mm and Hard gas permeable (GP) contact lenses have a diameter of about 8 mm. Soft CL totally cover the cornea as a result and cut down gas exchange of about 50%. Hard GP lenses not only cover only a part of the cornea and are gas permeable as well, but they also move up and down and side-to-side exposing more of the cornea for direct gas exchange. Not only that but after so many hours of CL wear, cornea suffers from hypoxia and causes blurring of vision due to corneal oedema or swelling. If allowed to continue for long periods, hypoxia causes new blood vessels to grow in the cornea as well as causing keratitis. If you suffer from dry eyes, you can also use artificial teardrops more so with hard GP lenses than soft CLs, which bind to preservatives in the eye drops.