Iris-recognition technology was designed to be less intrusive than retina scans, which often require infrared rays or bright light to get an accurate reading. Scientists also say a person's retina can change with age, while an iris remains intact. And no two iris blueprints are mathematically alike, even between identical twins and triplets. Charlotte/Douglas International Airport in North Carolina is acting as a testing ground for the biometric technology beginning this week. EyeTicket Corp., headquartered in McLean, Virginia, is the exclusive provider of the technique for both airline passengers and personnel.