Designing For Other Impairments By Jim Heid Given the graphical nature of the Web, it isn't surprising that blindness presents the most accessibility challenges. But maneuvering through Web sites also can be difficult for users with less severe visual impairments or other physical disabilities. Here are some additional accessibility issues to keep in mind when designing your Web site. Compensating for Vision Impairments Numerous forms of visual impairment exist, ranging from color blindness to glaucoma to the reduced visual acuity Father Time brings to us all. While these users can still read the screen, navigating through wild color schemes and screens of tiny text can still be challenging. A few simple design choices on your part can make using your site easier for everyone. Choose colors carefully. Doctors estimate that roughly one in every 12 males in the United States has some degree of color blindness. You'll improve legibility for everyone by using high-contrast color schemes (for example, black text on a white background) for text-intensive pages. Since the most common form of color blindness by far is red-green color blindness, avoid placing these colors next to one another on your page. And whatever you do, don't make color a cornerstone of your navigation scheme -- relying, for example, on a green button to continue and a red button to stop. Enable layouts to be resized. Users with poor eyesight may want to enlarge the text on your Web site. You can enable page text to be resized by the reader without sacrificing the overall integrity of your design by using Cascading Style Sheets and by specifying type sizes and layout values in ems rather than specific pixel values. An em is a relative unit of measurement; in the Web world, one em is equal to the browser's current default size. Since most current browsers default to 12-point type,