EP0105292A1 - Method of and telescopic spectacles for alleviating severe visual impairment - Google Patents

Abstract

A modified Galileo telescope consists of a contact lens (10) having a negative power of about twenty or thirty diopters, and an objective (12) with a positive power of fifteen to thirty diopters spaced about thirty millimeters in front of the contact lens (10).

Description

METHOD OF AND TELESCOPIC SFECTACLES FOR

ALLEVIATING SEVERE VISUAL IMPAIRMENT

This invention relates to a novel inethod of and telescopic spectacles for improving the visual acuity of persons who have greatly impair- ed vision. Brief Description:

Briefly, the invention proposes the use of a form of the Galilean telescope greatly to increase visual acuity, without restricting the field of view of persons with extrecnely poor vision such as those suffering from macular or retineal degeneration, or nystagmus, but whose corneas, lenses, and humours remain transparent. A contact lens of thirty or twenty diopters negative power is used in tandem with a positive objective lens of relatively high power and large diameter supported about thirty millimeters in front of the patient's cornea.

The modified telescope was fitted on one patient who, despite repeated efforts by eye specialists, had never been able to see more sharply than 20/70 in one eye and 20/200 in the other, and whose field of view was restric ted to an angle of about 7° by other, previously available telescopic visual aids. With the rcodified telescope, the patient's vision in one eye tested at 20/30, and in the other eye at 20/40, and her field of view was measured at about 140°. Detailed Description:

Illustrative embodiments of the invention will now be described in conjunction with the drawing, wherein:

Figure 1 is a schematic diagram of the spectacle system according to the invention;

Figure 2 is a perspective view of a pair of spectacles according to the invention as worn by a patient; and

Figure 3 is a perspective wiew of an alternative arrangement for supporting the objective lens portions of the spectacles. As shown in Figure 1, the spectacle system of the invention includes a contact lens 10 for application in the usual way to the patient's cornea. If the patient retains his natural crystalline lens, I.e. if the eye is phakic, the power of the contact lens 10 is about thirty diopters. If the eye is aphakic, a power of about twenty diopters is adequate. An objective lens 12 is optically aligned with the contact lens 10 spaced about thirty millimeters in front of it. The objective lens 12 is between about fifteen diopters and thirty diopters in power. It is also of relatively large diameter, preferably about eighty millimeters. The combination of the two lenses 10 and 12 constitutes a modified Galilean telescope that serves greatly to improve the vision of the patient without restricting his angular field of view.

Supporting a pair of objective lenses spaced thirty millimeters in front of the eyes presents a slightly awkward problem, especially in view of their high power and large diameter, which limit the degree to which their weight can be reduced. Several options, however, are readily apparent.

As shown in Figure 2, for example, the objective lenses 12 are held in a frameless arrangement supported on hangers 18 from a headband 20 and spaced to the front by a brow rest 22. A pair of tanples 24 serve to enhance lateral stability.

An alternative support arrangement is shwon in Figure 3. In this case the objective lenses are integrally molded in a curved, transparent visor 28 which is pivoted on a headband 30 at points adjacent to the wearer's ears, much like the visor co-monly seen on motorcycle helmets. The visor may be pivoted between a position atop the wearer's head and its operative position in front of the wearer's face. The operative position is optimized by adjusting a front support strap connected between the headband 30 and top of the visor 28.

The nature of the structural arrangement for supporting the objective lenses 12 or 26 in front of the eyes is not regarded as an essential element of the invention, but may be varied in accordance the designer's choice. It Is important, however, that the lenses be of relatively high power, at least about fifteen diopters, and, to avoid restricting the patient's angular field of view, that they be of relatively large diameter, say at least 70 mm. , and preferably about 80 mm. It is also highly desirable to minimize the scope of any peripheral structure such as the temples 24 and to use a transparent frame, or a frameless arrangement, so as to minimize obstructions in the peripheral field.

Claims

WHAT IS CIAIMED I:

1. Method of improving the vision of a person having severely impaired vision comprising fitting the person with a contact lens of relatively high negative power, and supporting a positive lens of relatively high power and large diameter spected about thirty millimeters in front of the contact lens and approximately optically aligned therewith.

2. Method according to claim 1 wherein the contact lens is of about twenty to about thirty diopters in power and the positive lens is of about fifteen to about thirty diopters.

3. Apparatus for improving the vision of a person having severely impaired vision comprising a contact lens of relatively strong negative power to be worn on the person's cornea, an objective lens of relatively strong positive power, and means for supporting the objective lens spaced about thirty millimeters in front of the person's cornea.

4. Apparatus according to claim 3 wherein the contact lens is of aoubt twenty diopters power for an aphakic eye or of about thirty diopters power for a phakic eye, and the objective lens is between about fifteen and thirty diopters power.