"twenty-twenty" meaning in English

{
  "etymology_text": "From a method of testing vision by reading charts at a distance of 20 feet.",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "twenty-twenty (not comparable)",
      "name": "en-adj"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "adj",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English reduplicated coordinated pairs",
          "parents": [
            "Reduplicated coordinated pairs",
            "Coordinated pairs",
            "Reduplications",
            "Terms by etymology"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Twenty",
          "orig": "en:Twenty",
          "parents": [
            "Numbers",
            "All topics",
            "Terms by semantic function",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Vision",
          "orig": "en:Vision",
          "parents": [
            "Senses",
            "Perception",
            "Body",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "coordinate_terms": [
        {
          "word": "6/6"
        },
        {
          "word": "six-six"
        }
      ],
      "derived": [
        {
          "word": "twenty-twenty hindsight"
        }
      ],
      "examples": [
        {
          "ref": "1978, “Picture This”, in Debbie Harry (lyrics), Parallel Lines, performed by Blondie:",
          "text": "All I want is 20/20 vision / A total portrait with no omissions",
          "type": "quote"
        }
      ],
      "glosses": [
        "Having normal visual acuity."
      ],
      "id": "en-twenty-twenty-en-adj-Sm5grijW",
      "links": [
        [
          "normal",
          "normal"
        ],
        [
          "visual",
          "visual"
        ],
        [
          "acuity",
          "acuity"
        ]
      ],
      "synonyms": [
        {
          "word": "20/20"
        }
      ],
      "tags": [
        "not-comparable"
      ]
    }
  ],
  "word": "twenty-twenty"
}

{
  "coordinate_terms": [
    {
      "word": "6/6"
    },
    {
      "word": "six-six"
    }
  ],
  "derived": [
    {
      "word": "twenty-twenty hindsight"
    }
  ],
  "etymology_text": "From a method of testing vision by reading charts at a distance of 20 feet.",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "twenty-twenty (not comparable)",
      "name": "en-adj"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "adj",
  "senses": [
    {
      "categories": [
        "English adjectives",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English reduplicated coordinated pairs",
        "English terms with quotations",
        "English uncomparable adjectives",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Twenty",
        "en:Vision"
      ],
      "examples": [
        {
          "ref": "1978, “Picture This”, in Debbie Harry (lyrics), Parallel Lines, performed by Blondie:",
          "text": "All I want is 20/20 vision / A total portrait with no omissions",
          "type": "quote"
        }
      ],
      "glosses": [
        "Having normal visual acuity."
      ],
      "links": [
        [
          "normal",
          "normal"
        ],
        [
          "visual",
          "visual"
        ],
        [
          "acuity",
          "acuity"
        ]
      ],
      "tags": [
        "not-comparable"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "20/20"
    }
  ],
  "word": "twenty-twenty"
}