Visual acuity examination
A vision screening apparatus conducts a photorefraction ocular screening test to generate refractive error data. Based on the refractive error data, a Snellen equivalent is determined. An evaluated person distance from the vision screening apparatus is also determined and used to generate an adjusted optotype size. The vision screening apparatus displays the optotype, adjusted for the Snellen equivalent and the evaluated person distance.
1. A vision screening apparatus, comprising:
a processing unit;
a range finder operably connected to the processing unit; and
memory storing instructions that, when executed by the processing unit, cause the vision screening apparatus to:
receive information indicating an acuity threshold associated with a group of people, the group of people including a person to be evaluated;
determine a Snellen equivalent based on an evaluation of a refractive error result, the Snellen equivalent indicating a predicted visual acuity of the person;
determine that the predicted visual acuity exceeds the acuity threshold;
based on determining that the predicted visual acuity exceeds the acuity threshold, select an optotype size corresponding to the acuity threshold associated with the group of people;
determine, using the range finder, a distance extending from the person to the vision screening apparatus;
based on the distance and the optotype size, determine an adjusted optotype size; and
display an optotype having the adjusted optotype size.
2. The vision screening apparatus according to claim 1 , the memory further storing instructions that, when executed by the processing unit, cause the vision screening apparatus to:
perform a photorefraction ocular screening test, thereby generating the refractive error result;
transmit a request to a server for the Snellen equivalent, the request including the refractive error result; and
receive a response from the server, the response including the Snellen equivalent.
3. The vision screening apparatus according to claim 1 , the memory further storing instructions that, when executed by the processing unit, cause the vision screening apparatus to:
receive an age of an evaluated person; and
based on the age, adjust the optotype to an age-appropriate optotype, the age-appropriate optotype being displayed in the adjusted optotype size.
4. The vision screening apparatus according to claim 3 , the age-appropriate optotype comprising a non-text optotype including at least one of:
an object and a shape.
5. The vision screening apparatus according to claim 1 , further comprising:
a first display unit;
a second display unit;
an image sensor unit;
the memory further storing instructions that, when executed by the processing unit, cause the vision screening apparatus to:
display the refractive error result on the first display unit; and
display the optotype on the second display unit.
6. The vision screening apparatus according to claim 1 , the instructions further causing the vision screening apparatus to:
perform a photorefraction ocular screening test, thereby generating the refractive error result;
select a visual acuity determination process, from a plurality of visual acuity determination processes, based on the refractive error result, the visual acuity determination process comprising one of:
a first process utilizing a component configured for use with a myopic evaluated person, or
a second process different from the first process and utilizing a component configured for use with a hyperopic evaluated person.
7. The vision screening apparatus according to claim 1 , the memory further storing instructions that, when executed by the processing unit, cause the vision screening apparatus to display a fogged optotype.
8. The vision screening apparatus according to claim 1 , the instructions further causing the visual acuity screening apparatus to:
generate movement instructions based on the evaluated person distance; and
output the movement instructions, the movement instructions indicating a desired change in the evaluated person distance.
9. The vision screening apparatus according to claim 1 , wherein the adjusted optotype size comprises a dynamic size characterized by a dimension that is substantially continuously adjusted throughout a vision screening test, in real time, based on distances determined using the range finder.
10. The vision screening apparatus according to claim 1 , the Snellen equivalent being determined using at least one of: spherical equivalent, sphere, cylinder, axis, gaze angle, pupil diameter, and interpupillary distance, and wherein causing the vision screening apparatus to display the optotype having the adjusted optotype size comprises causing the vision screening apparatus to display a single line of optotypes to the person, the optotypes in the single line of optotypes including having sizes substantially equivalent to the adjusted optotype size.
11. A visual acuity screening apparatus, comprising:
a processing unit;
a range finder operably connected to the processing unit; and
memory storing instructions that, when executed by the processing unit, cause the visual acuity screening apparatus to:
perform, on a person of a group of people, a photorefraction ocular screening test, thereby generating refractive error data associated with the person;
transmit a request to a server for a Snellen equivalent, the request including the refractive error data;
receive a response from the server, the response including the Snellen equivalent, the Snellen equivalent indicating a predicted visual acuity of the person;
receive information indicating an acuity threshold associated with the group of people;
determine that the predicted visual acuity exceeds the acuity threshold;
based on determining that the predicted visual acuity exceeds the acuity threshold, select an optotype size corresponding to the acuity threshold associated with the group of people;
determine, using the range finder, a distance extending from the person to the visual acuity screening apparatus;
based on the distance and the optotype size, determine an adjusted optotype size;
display an optotype having the adjusted optotype size; and
display a fogged optotype.
12. The visual acuity screening apparatus according to claim 11 , the memory further storing instructions that, when executed by the processing unit, cause the visual acuity screening apparatus to:
receive an age of an evaluated person; and
based on the age, adjust the optotype to an age-appropriate optotype, the age-appropriate optotype being displayed in the adjusted optotype size, the age-appropriate optotype including at least one of: an object, a shape, a number, and a letter.
13. The visual acuity screening apparatus according to claim 12 , further comprising:
a first display unit;
a second display unit;
an image sensor unit;
the memory further storing instructions that, when executed by the processing unit, cause the visual acuity screening apparatus to:
display the refractive data result on the first display unit; and
display the optotype on the second display unit.
14. The visual acuity screening apparatus according to claim 11 , the instructions further causing the visual acuity screening apparatus to:
generate movement instructions based on the evaluated person distance; and
output the movement instructions, the movement instructions indicating a desired change in the evaluated person distance.
15. The visual acuity screening apparatus according to claim 14 , the evaluated person distance being updated throughout a modified Snellen test;
the adjusted optotype size being adjusted throughout the modified Snellen test; and
the Snellen equivalent being determined using at least one of: spherical equivalent, sphere, cylinder, axis, gaze angle, pupil diameter, and interpupillary distance.