oskar and JD, the provision is a part of Texas state law - it applies to all state employees, including teachers. Even janitors can take advantage of the provision. It's not limited to "high-level employees."
Sec. 814.104. ELIGIBILITY OF MEMBER FOR SERVICE RETIREMENT. (a) Except as provided by Subsection (d) of this section, Section 814.102, or by rule adopted under Section 813.304(d) or 803.202(a)(2), a member who has service credit in the retirement system is eligible to retire and receive a service retirement annuity if the member:
(1) is at least 60 years old and has at least 5 years of service credit in the employee class; or
(2) has at least 5 years of service credit in the employee class and the sum of the member's age and amount of service credit in the employee class, including months of age and credit, equals or exceeds the number 80.
(b) A member who is at least 55 years old and who has at least 10 years of service credit as a commissioned peace officer engaged in criminal law enforcement activities of the Department of Public Safety, the Texas Alcoholic Beverage Commission, the Parks and Wildlife Department, or the office of inspector general at the Texas Youth Commission, or as a custodial officer, is eligible to retire and receive a service retirement annuity.
(c) For the sole purpose of determining eligibility to receive a service retirement annuity, the retirement system shall consider service performed as a participant in the optional retirement program under Chapter 830 as if it were service for which credit is established in the retirement system.
(d) Except as provided by Section 814.102 or by rule adopted under Section 813.304(d) or 803.202(a)(2), a member who was not a member on the date hired, was hired on or after September 1, 2009, and has service credit in the retirement system is eligible to retire and receive a service retirement annuity if the member:
(1) is at least 65 years old and has at least 10 years of service credit in the employee class; or
(2) has at least 5 years of service credit in the employee class and the sum of the member's age and amount of service credit in the employee class, including months of age and credit, equals or exceeds the number 80.