The COVID-19 pandemic has changed the way we interact with public administration, making indispensable the use of online public services (e-services) to perform required administration procedures. All citizens should be able to interact with public e-services in an autonomous, satisfactory and easy way. However, these services are not always accessible to people with disabilities. In this paper, we present a descriptive model for e-services adaptation based on ontologies, which contains the e-service annotations, user features and techniques required for adapting e-services to the needs of people with disabilities. Based on this model, an automated adaptation system was developed and adapted versions of three different Spanish public e-services aiming at users with low vision were obtained as a proof of concept.