###### Abstract
The image-based or video-based method uses image processing techniques to achieve success in diagnosing strabismus [18, 19, 20, 21, 22]. [PERSON] [18] proposed a store-and-forward telemedicine consultation technique that uses a digital camera and a computer to obtain patient images and then transmits them by email, so the diagnosis and treatment plan could be determined by the experts, according to the images. This was an early attempt to apply new resources to aid the diagnosis of strabismus. [PERSON] [19] presented a computerized method of measuring binocular alignment, using a selective wavelength filter and an infrared camera. Automated image analysis showed an excellent agreement with the traditional PCT (prism and alternate cover test). However, the subjects who had an extreme proportion that fell out of the normal variation range, could not be examined using this system, because of its software limitations. Then in [20], they implemented an automatic strabismus examination system that used an infrared camera and liquid crystal shutter glasses to simulate a cover test and a digital video camera, to detect the deviation of eyes. [PERSON] et al. [21] proposed a four-stage methodology for automatic detection of strabismus in digital images, through the Hirschberg test: (1) finding the region of the eyes; (2) determining the precise location of eyes; (3) locating the limbus and the brightness; and (4) identifying strabismus. Finally, it achieved a 94% accuracy in classifying individuals with or without strabismus. However, the Hirschberg test was less precise compared to other methods like the cover test. Then in [22], [PERSON] presented a computational methodology to automatically diagnose strabismus through digital videos featuring a cover test, using only a workstation computer to process these videos. This method was recognized to diagnose strabismus with an accuracy value of 87%. However, the effectiveness of the method was considered only for the horizontal strabismus and it could not distinguish between the manifest strabismus and the latent strabismus. The eye-tracking technique was also applied for strabismus examination [23; 24; 25; 26; 27]. [PERSON] and [PERSON] [23] presented a photographic method, based on corneal light reflection for the measurement of binocular misalignment, which allowed for the measurement of eye alignment errors to fixation targets presented at any distance, throughout the subject's field of gaze. [PERSON] and [PERSON] [24] built up a remote two-camera gaze-estimation system for the AHT (Automated Hirschberg Test) to measure binocular misalignment. However, the accuracy of the AHT procedure has to be verified with a larger sample of subjects, as it was studied on only five healthy infants. In [25], [PERSON] proposed a new method prototype to study the eye movement where gaze data were collected using the Tobii eye tracker, to conduct ophthalmic examination, including strabismus, by calculating the angles of deviation. However, the thesis focused on the development of the new method to provide repeatability, objectivity, comprehension, relevance, and independence and lacked an evaluation of patients. In [26], [PERSON] et al. developed an eye-tracking-aided digital system for strabismus diagnosis. The subject's eye alignment condition was effectively investigated by intuitively analyzing gaze deviations, but only a strabismic person and a normal person were asked to participate in the experiments. Later, in [27], [PERSON] et al developed a more effective eye-tracking system to acquire gaze data for strabismus recognition. Particularly, they proposed a gaze deviation image to characterize eye-tracking data and then leveraged the Convolutional Neural Networks to generate features from gaze deviation image, which finally led to an effective strabismus recognition. However, the performance of the proposed method could be further evaluated with more gaze data, especially data with different strabismus types. In this study, we have proposed an intelligent evaluation system for strabismus.