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Scheme of the accommodation box: lighting system (2), eyepiece (3), optotype sheets (4), pushbuttons (5) eye (6)

Scheme of the accommodation box: lighting system (2), eyepiece (3), optotype sheets (4), pushbuttons (5) eye (6).

We present a box of a light material that includes a set of sheets with ophthalmic lenses, a sheet with optotypes of different sizes that subtend the same angle with any combination of negative lenses interposed. The device eliminates the subjective errors of the test committed by the optometrist in the evaluation of the accommodation. Furthermore the downsize of the optotype is achieved because of the increase of the power of the ophthalmic lenses.

How does it work

Accommodation is the physiological ability of focusing both eyes. It is measured, under usual conditions, using letters or ophthalmic lenses with the compensation of ametropia.

In Optometry, two methods are used to evaluate the accommodation, the first using ophthalmic lenses and the second is the push-up method. Any measurement of these methods is always subjective and the accuracy of the data depends on the ability of the vision specialist. The technique of measuring the amplitude of accommodation with negative lenses has a major drawback, which wants to solve this invention, and which consists of a reduction in the size of the optotype, by increasing the power of the ophthalmic lenses.

This new equipment allows the measurement of the amplitude of accommodation, with the use of ophthalmic lenses, in people of any age.

The invention consists of a box about 40 cm high, with a circular sheet with optotypes printed in different sizes and with its own lighting system. In addition, a series of five parallel sheets, also circular and all of the same diameter, are used. Each of these sheets contains four ophthalmic lenses of different powers. In the center of each sheet a circular hole is pierced through which passes a cylindrical bar that serves as support and axis of rotation.


Optotypes sheet, with different sizes

Description of the device: 1. Visual occlusor. 2. Hinge. 3. Millimeter scale. 4. Optotype rail. 5 Optotype button. 6. Optotype. 7. Flashlight. 8. Longitudinal axis of the handle

• Reduces the size of the optotype, by increasing the power of ophthalmic lenses.

• The circular type optotype allows the change of the size of the optotype, from lowest to highest value in mm.

• The measurement of blur is avoided with the size of the presented letter, larger.

• The greater power of the ophthalmic lens produces an optical effect typical of the characteristics of this type of lens, which allows a reduction

• Eliminates test errors.

Where has it been developed?

The design, protected by national patent with previous examination since 2012, and its prototype, have been developed in the Faculty of Optics and Optometry.



© Office for the Transfer of Research Results – UCM
Faculty of Medicine. Edificio Entrepabellones 7 y 8.
C/ Doctor Severo Ochoa, 7. 28040 Madrid.

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Health Sciences


Responsible Researcher

Ricardo Bernárdez Vilaboa: rbvoptom@ucm.es

Department: Optometry and Vision

Faculty: Optics and Optometry