He looked at my black eye patch and grinned.

"You look," he said, "like the Hathaway man."

I smiled back, although I'd heard that joke twice today.

I have a "visual impairment." I'm not blind, but I have deteriorating eyesight that cannot be corrected by glasses or surgery.

Except for those occasional days when I wear my eye patch, my impairment is not noticeable, as it is not for this country's 10 million or so others.

Coping with a visual impairment, for me, often means having a sense of humor. And a lot of patience. Often I can't read normal-size print. Some days I can't even read the destination name on the front of the bus. And I've been known to walk into trees. So sometimes I need special kinds of help and information:

1. How can I dial the telephone when I can't read the numbers on the dial?

2. How can I get my fill of my favorite newspaper columnists when I can't read the newspaper?

3. How can I satisfy my craving for a good murder mystery or a best-seller when I can't read a book?

Finding the answers to those questions was difficult

Answer 1. A simple, inexpensive device with huge numbers and letters, attaching easily to the telephone, is available from the American Foundation for the Blind.

Answer 2. The Washington Ear, a free closed-circuit radio service, reads excerpts from The Washington Post every day.

Answer 3. The National Library Service for the Blind and Physically Handicapped has hundreds of books on records and tapes, distributed free through public libraries nationwide.

I have, however, a lot more questions.

Sorting out which organizations -- public and private -- provide what services is complicated. There are many that serve the "legally blind," but most don't provide help to the "visually impaired." And most organizations that do aren't widely known.

I've found out who publishes a large-print dictionary, but now I wonder what else is available in large print: information, for example, which could be included in a complete directory for the visually impaired in the Washington area.

Also, many people could benefit from the kind of self-help groups or "buddy" phone-support systems, such as those set up in Massachusetts by Vision Foundation. I know of no such groups in this area.

Here are some services, however, for the "visually impaired," or those unable to read normal size print:

* The Washington Ear, Inc. -- Provides free, closed-circuit radio reading service broadcast over a sub-carrier channel of WETA-FM. They read The Washington Post every day -- even the comics -- as well as The Wall Street Journal, magazines, books. A special pre-tuned receiver is loaned free. 35 University Blvd. E., Silver Spring, Md. 20901. Call 681-6636.

* National Library Service for the Blind and Physically Handicapped / Library of Congress -- Produces full-length books and magazines on records and cassettes. The Talking Books, and the specially designed phonographs and cassette players they require, are loaned free through a system of regional and sub-regional public libraries nationwide. Thousands of titles are available and about 2,500 new titles are added every year.

The NLS also publishes many reference circulars. List available. If outside the Washington area, contact the NLS at 800-424-9100. Otherwise, contact one of these area libraries for more information:

Alexandria Library, Talking Books, John Adams Center, 5651 Rayburn Ave., Alexandria, Va. 22311, 998-5463.

Arlington County Department of Libraries, Talking Book Service, 1015 North Quincy St., Arlington, Va. 22201, 527-4777, Ext. 56.

District of Columbia Regional Library for the Blind and Physically Handicapped, 901 G St NW, Room 215, Washington, D.C. 20001. 727-2142.

Fairfax County Public Library, John Marshall Branch, 6209 Rose Hill Dr., Alexandria, Va. 22310, 971-0030.

Montgomery County Department of Public Libraries, Service for the Physically Handicapped, 99 Maryland Ave., Rockville, Md. 20850, 279-1679.

Prince George's County Memorial Library System, Division for the Visually and Physically Handicapped, 6532 Adelphi Rd., Hyattsville, Md. 20782. 779-9330, Ext. 28.

* American Foundation for the Blind -- Sells such items as large-print telephone dials, self-threading sewing needles, magnifiers and large-print playing cards. Free catalog, Products for People with Vision Problems, available from their Consumer Products Department, 15 W. 16th St, New York, N.Y. 10011, 212-620-2000.

* National Association for Visually Handicapped -- National agency that serves as an advocacy group and information center, publishes a quarterly newsletter, sells some aids and devices and publishes information booklets (some in large print). Offers free packet of materials. 305 E. 24th St., New York, N.Y. 10010, 212-889-3141.

* Recording for the Blind, Inc. -- Provides recorded educational and career books free on loan. Their Master Tape Library includes over 50,000 titles. Will record books not presently available. 215 E. 58th St., New York, N.Y. 10022, 212-751-0860.

* Vision Foundation, Inc. -- Information center and self-help organization which publishes Coping with Sight Loss: The Vision Resource Book. The directory covers national agencies and organizations, financial benefits and legal rights of the blind, reading aids, reference books in special media, aids and devices, low-vision services, and much more. Although written primarily for Massachusetts residents, the first half covers services available nationwide. Available at $10 for the large-print edition and for the voice-indexed cassette.

Large-Print Inventory List, Vol. 4, is a free catalog of 100 informational brochures (most of them free) from around the country. Also available on cassette, $2. Vision Foundation, Inc.: 770 Centre St., Newton, Mass. 02158. 617-965-5877.