Data owners with large volumes of data can outsource spatial databases by taking advantage of the cost-effective cloud computing model with attractive on-demand features such as scalability and high computing power. Data confidentiality in outsourced databases is a key requirement and therefore, untrusted third-party service providers in the cloud should not be able to view or manipulate the data. This paper proposes DISC (Dynamic Index for Spatial data on the Cloud), a secure retrieval scheme to answer range queries over encrypted databases at the Cloud Service Provider. The dynamic spatial index is also able to support dynamic updates on the outsourced data at the cloud server. To be able to support secure query processing and updates on the Cloud, spatial transformation is applied to the data and the spatial index is encrypted using Order-Preserving Encryption. With transformation and cryptography techniques, DISC achieves a balance between efficient query execution and data confidentiality in a cloud environment. Additionally, a more secure scheme, DISC*, is proposed to balance the trade-off between query results returned and security provided. The security analysis section studies the various attacks handled by DISC. The experimental study demonstrates that the proposed scheme achieves a lower communication cost in comparison to existing cloud retrieval schemes.