Instrument for measuring near point of convergence and/or near point of accommodation

An instrument for measuring near point of convergence (NPC) and/or near point of accommodation (NPA), the instrument comprising:

• an instrument housing, the instrument housing including a front surface and a rear surface disposed opposite to the front surface;
• at least one visual target disposed on or in the front surface of the instrument housing, the at least one visual target viewable by the subject when the subject is facing the front surface of the instrument;
• a distance measuring device disposed on or in the front surface of the instrument housing, the distance measuring device configured to emit one or more output signals that are representative of a distance between a measurement reference point of the instrument and a body surface of the subject spaced apart from the measurement reference point of the instrument;
• a camera disposed on or in the front surface of the instrument housing, the camera configured to capture a pupil image of the subject while the subject is being tested using the instrument;
• a processing device disposed within the instrument housing, the processing device operatively coupled to the distance measuring device and the camera, the processing device configured to receive the one or more output signals that are output by the distance measuring device and to calculate a plurality of distances between the measurement reference point of the instrument and the body surface of the subject spaced apart from the measurement reference point of the instrument using the one or more output signals, the processing device further configured to determine a pupil size of the subject from the pupil image of the subject captured by the camera;
• and
• a visual display device operatively coupled to the processing device, the visual display device configured to display the plurality of distances calculated by the processing device to the user of the instrument for at least two vision test measurement parameters of the subject, the at least two vision test measurement parameters selected from the group consisting of near point of convergence (NPC), near point of convergence recovery (NPCr), near point of accommodation (NPA), and near point of accommodation recovery (NPAr);
• wherein the instrument is in the form of a handheld instrument, and the user of the instrument is configured to hold the instrument housing during the use of the instrument.

A method for measuring near point of convergence (NPC) and/or near point of accommodation (NPA) of a subject, the method comprising the steps of:

• providing an instrument that includes:
• an instrument housing, the instrument housing including a front surface and a rear surface disposed opposite to the front surface, the instrument housing having a length and a width, the width of the instrument housing being less than the length of the instrument housing so as to enable a user of the instrument to view the eyes of a subject while the subject is being tested using the instrument;
• at least one visual target disposed on or in the front surface of the instrument housing, the at least one visual target viewable by the subject when the subject is facing the front surface of the instrument;
• a distance measuring device disposed on or in the front surface of the instrument housing, the distance measuring device configured to emit one or more output signals that are representative of a distance between a measurement reference point of the instrument and a body surface of the subject spaced apart from the measurement reference point of the instrument;
• a processing device disposed within the instrument housing, the processing device operatively coupled to the distance measuring device, the processing device configured to receive the one or more output signals that are output by the distance measuring device and to calculate a plurality of distances between the measurement reference point of the instrument and the body surface of the subject spaced apart from the measurement reference point of the instrument using the one or more output signals;
• and
• a visual display device operatively coupled to the processing device, the visual display device configured to display the plurality of distances calculated by the processing device to the user of the instrument for at least two vision test measurement parameters of the subject, the at least two vision test measurement parameters selected from the group consisting of near point of convergence (NPC), near point of convergence recovery (NPCr), near point of accommodation (NPA), and near point of accommodation recovery (NPAr);
• wherein the instrument is in the form of a handheld instrument, and the user of the instrument is configured to hold the instrument housing during the use of the instrument;
• displaying, by using the instrument, the at least one visual target to the subject so that the subject is able maintain his or her gaze on the at least one visual target while the user of the instrument observes the eyes of the subject;
• determining and recording, by using the instrument, the plurality of distances for the at least two vision test measurement parameters of the subject;
• and
• displaying the plurality of distances calculated by the processing device to the user on the visual display device for the at least two vision test measurement parameters of the subject.