It may have been David Siesel’s fastest medical appointment ever. Last week the 35-year-old Wang Laboratories manager had his eyes examined and was back at his computer screen with new glasses in less than an hour. By visiting the optometrist sent to Wang by HealthDrive, a mobile health-care provider, Siesel never had to leave his company’s headquarters in Lowell, Mass. “For something like an eye appointment, taking time away from work would be excessive,” says Siesel. His employer couldn’t have been happier. Wang’s manager of health services, Joan Newell, says the workplace system is “a great convenience.”

Today the doctor is in-in your office, your hotel room and just about anywhere else. As medical technology becomes more portable, it’s easier for some doctors to take their practices on the road. Doctors To Your Door in Louisville, Ky., offers old-fashioned house calls to bedridden elderly patients and ailing executives. San Diegobased Call Doctor, Inc., sends a van packed with $300,000 worth of diagnostic equipment and a board-certified physician to provide emergency treatment at home or the workplace. And HealthDrive, which is based in Chestnut Hill, Mass., dispatches fully equipped dental- and eye-care teams to corporate sites and government offices, as well as nursing homes. “Doctors stopped making house calls partly because they couldn’t take their tools with them,” says Call Doctor president Dr. Gresham Bayne. “Now we’ve put the tools in today’s black bag-a van.”

A growing number of firms such as Wang seek the services of mobile medical companies, partly as a way to control mounting health-care bills. Having the doctor drive up to the office is part of a larger trend toward bringing medical care directly to workers. A few corporations even hire outside medical companies to run family health-care clinics in the workplace. At the headquarters of Adolph Coors Co., the huge brewer, Philadelphia-based Liberty Healthcare Corp. can handle everything “from sniffles to heart attacks,” according to its president, Dr. Herbert Caskey. MediCenter Inc. of Lawton, Okla., runs four facilities for The Goodyear Tire & Rubber Co. that boast optical services, mammographies and free pharmacies.

Fans of workplace medical care say it offers relief to cash-crunched companies. Most companies pay the in-house physicians a salary, eliminating one incentive to overtreat. Morris Gross, vice president of Corporate Health Care in Danbury, Conn., says savings stem from efficiency, too: a physical therapist can treat up to three patients at a plant for a $50 hourly charge, far less than separate office visits would cost. According to health-care providers, fees as low as $15 per patient encourage employees burdened with high insurance deductibles to use the system at the first sign of trouble-often nipping problems before they require more expensive treatment. The benefits add up: Goodyear estimates it saved close to $1 million last year. And on-site physicians say their services help employers know exactly what they are paying for. Traditionally, “the company has no idea what quality of care an employee is getting,” says Caskey. “They’re just paying for it.”

On-the-job medical treatment still has its critics. Some workers see the visiting doctor as a potential spy for the boss: they don’t want the company to know what ails them. Employees who wouldn’t think twice about getting a cavity filled by an on-site dentist might balk at consulting a psychologist at the office. One California insurance company brought in a psychotherapist twice a week, but employees stayed away. Union workers at a Goodyear plant in Gadsden, Ala., insisted on confidentiality before approving a work-site clinic. Also, bringing the doctor in doesn’t always save companies money: Coors found that the company’s surgery rate had shot up after periodic orthopedic visits.

Despite the problems, industry analysts expect medicine-on-wheels to catch on-and doctors are finding more places to park all the time. One Detroit firm, Hotel Doctor, rakes in $2 million in annual revenues by making about 200 “hotel calls” a week. Of course, this doesn’t mean you’re likely to see a doctor with a black bag in your office next week-or even next year. But with the number of physicians on the rise, better service may become a selling point. For patients who have spent countless hours thumbing old magazines in doctors’ waiting rooms, that’s welcome news.