Diffractive/refractive lens implant

• US 5,089,023 A
• Filed: 03/22/1990
• Issued: 02/18/1992
• Est. Priority Date: 03/22/1990
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Swanson, Gary J.
• Primary Examiner(s): Frinks, Ronald
• Application Number:
  US07/497,860
• Time in Patent Office: 698 Days
• Field of Search: 623/6, 623/4, 623/5, 351/161, 351/162
• US Class Current: 623/6.25
• CPC Class Codes: A61F 2/1618 Multifocal lenses
• CPC Class Codes: A61F 2/1654 Diffractive lenses
• CPC Class Codes: G02B 5/1876 Diffractive Fresnel lenses; Zone plates; Kinoforms G02B5/1842, G02B5/1847 take precedence; optical systems having diffractive correction means G02B27/0037; Fresnel lenses operating by refraction G02B3/08
• CPC Class Codes: G02B 5/188 Plurality of such optical elements formed in or on a supporting substrate
• CPC Class Codes: G02B 5/1895 such optical elements having dioptric power

Abstract

In an intraocular optical implant including a refractive/diffractive lens having an anterior surface and a posterior surface and a generally anterior-posterior optical axis, at least one of the surfaces has a diffractive lens profile covering about half the effective lens area of the lens. Preferably the diffractive lens profile occupies a sectoral portion of the effective lens area, as for example a semicircular sectoral portion, or a plurality of sectoral portions the sum of whose subtended angles is about 180°, as for example two sectoral portions each of whose subtended angles is about 90°.

Claims

1. An intraocular optical implant comprising a refractive/diffractive lens having an anterior surface and a posterior surface and a generally anterior-posterior optical axis, at least one of said anterior and posterior surfaces having a diffractive lens profile covering about half the effective lens area of said lens.

2. The implant of claim 1 wherein said diffractive lens profile comprises a Fresnel phase zone plate profile.

3. The implant of claim 2 wherein said diffractive lens profile comprises a blazed diffraction lens profile.

4. The implant of claim 2 wherein said diffractive lens profile comprises a stepped diffractive lens profile.

5. The implant of claim 3 or 4 wherein said diffraction zone profile has a thickness D given by ##EQU8## where λ

.sub.°

is about 550 nm.

6. The implant of claim 1 wherein said diffractive lens profile comprises at least one sectoral portion of said effective lens area.

7. The implant of claim 6 wherein said diffractive lens profile comprises a semicircular sectoral portion of said effective lens area.

8. The implant of claim 6 wherein said diffractive lens profile comprises a plurality of sectoral portions of said effective lens area, the sum of whose subtended angles is about 180°

.

9. The implant of claim 8 wherein said diffractive lens profile comprises two sectoral portions of said effective lens area, each of whose subtended angles is about 90°

.