"master eye" meaning in English

{
  "forms": [
    {
      "form": "master eyes",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "master eye (plural master eyes)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Eye",
          "orig": "en:Eye",
          "parents": [
            "Face",
            "Vision",
            "Head and neck",
            "Senses",
            "Body parts",
            "Perception",
            "Body",
            "Anatomy",
            "Human",
            "Biology",
            "Medicine",
            "All topics",
            "Sciences",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "One's dominant eye, from which visual input is preferred."
      ],
      "id": "en-master_eye-en-noun-QQslRBJL",
      "related": [
        {
          "word": "eyedness"
        }
      ]
    }
  ],
  "word": "master eye"
}

{
  "forms": [
    {
      "form": "master eyes",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "master eye (plural master eyes)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "eyedness"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "en:Eye"
      ],
      "glosses": [
        "One's dominant eye, from which visual input is preferred."
      ]
    }
  ],
  "word": "master eye"
}