Table 1. An operational definition of the Five Stages of Adaptation.

Each of the five stages in the proposed framework is defined by observable behavioral evidence and explicit exclusion rules, allowing reported outcomes from diverse clinical, psychophysical, and qualitative studies to be evaluated using a common classification framework.

Stage	Functional Meaning	Observable Inclusion Criteria	Explicit Exclusion Criteria	Minimum Reporting Required	Typical Task
1 Device Activation	The system produces sensory percepts.	Detection or categorical localization of stimulation; phosphenes time-locked to stimulation.	Subjective statements of sensation without controlled confirmation.	Any controlled detection task or documented reproducible percept elicited by stimulation.	nAFC phosphene detection paradigms; threshold estimation.
2 Perceptual Calibration	The percept carries interpretable stimulus information.	Discrimination of spatial, temporal, or motion properties requiring finer mapping in laboratory tasks.	Simple detection, brightness judgment, or awareness without discrimination.	Discrimination or mapping task demonstrating stimulus-dependent percept variation.	Spatial localization; orientation, direction-of-motion, or size discrimination.
3 Cognitive Integration	Artificial vision is used to perform goal-directed tasks.	Object identification, visuo-motor integration, interpretation of visual patterns.	Only forced-choice tasks reported; performance relying solely on scanning strategy without interpretation.	A task where vision serves as an information source rather than a detection cue.	Letter, shape, object recognition; word reading; closed-set identification; hand-eye coordination.
4 Behavioral Generalization	Artificial vision transfers beyond structured testing.	Use in real-world activities without experimenter control.	Performance restricted to laboratory or training environments.	Use of vision in natural settings or unsupervised environments.	Door finding; line following; obstacle avoidance; daily living tasks.
5 Psychosocial Adjustment	Artificial vision becomes voluntarily adopted.	Sustained everyday use, preference over non-visual strategies, or lifestyle integration.	Occasional, novelty-driven, therapist-prompted, or demonstration use.	Long-term voluntary use outside training context.	Device logs; longitudinal retention; quality-of-life instruments; structured interviews.