Corneal biomechanics play a fundamental role in the genesis and progression of corneal pathologies, such as keratoconus; in corneal remodeling after corneal surgery; and in affecting the measurement accuracy of glaucoma biomarkers, such as the intraocular pressure (IOP). Air-puff induced corneal deformation imaging reveals information highlighting normal and pathological corneal response to a non-contact mechanical excitation. However, current commercial systems are limited to monitoring corneal deformation only on one corneal meridian. Here, we present a novel custom-developed swept-source optical coherence tomography (SSOCT) system, coupled with a collinear air-puff excitation, capable of acquiring dynamic corneal deformation on multiple meridians. Backed by numerical simulations of corneal deformations, we propose two different scan patterns, aided by low coil impedance galvanometric scan mirrors that permit an appropriate compromise between temporal and spatial sampling of the corneal deformation profiles. We customized the air-puff module to provide an unobstructed SSOCT field of view and different peak pressures, air-puff durations, and distances to the eye. We acquired multi-meridian corneal deformation profiles (a) in healthy human eyes in vivo, (b) in porcine eyes ex vivo under varying controlled IOP, and (c) in a keratoconus-mimicking porcine eye ex vivo. We detected deformation asymmetries, as predicted by numerical simulations, otherwise missed on a single meridian that will substantially aid in corneal biomechanics diagnostics and pathology screening.

http://digital.csic.es/bitstream/10261/230775/1/Multi-meridian%20corneal%20imaging.pdf

Multi-meridian corneal imaging of air-puff induced deformation for improved detection of biomechanical abnormalities.

Biometric measurement of the anterior segment is of great importance for the ophthalmology, human eye modeling, contact lens fitting, intraocular lens design, etc. This paper serves as a comprehensive review on the historical development and basic principles of the technologies for measuring the geometric profiles of the anterior segment. Both the advantages and drawbacks of the current technologies are illustrated. For in vivo measurement of the anterior segment, there are two main challenges that need to be addressed to achieve high speed, fine resolution, and large range imaging. One is the motion artefacts caused by the inevitable and random human eye movement. The other is the serious multiple scattering effects in intraocular turbid media. The future research perspectives are also outlined in this paper.

https://www.mdpi.com/1424-8220/20/15/4285/pdf

Biometric Measurement of Anterior Segment: A Review.

Purpose Accommodating intraocular lenses (A-IOLs) require capturing the ciliary muscle forces. Prior work demonstrated strong photo-initiated bonding between strips of capsular bag and poly(2-hydroxyethyl methacrylate); (pHEMA) polymer in an extraocular setting. We demonstrate that photobonding can be achieved intraocularly. Methods Phacoemulsification was performed in porcine eyes ( 45 years old. Intraocular bonding of polymer material to ocular tissue also may find other applications in ophthalmology.

/pdf/intraocular-photobonding-to-enable-accommodating-intraocular-13nqr62hm3.pdf

Intraocular Photobonding to Enable Accommodating Intraocular Lens Function

A multi-piece IOL assembly is provided that includes a platform and an optic The platform has an inner periphery surrounding an inner zone of the platform The optic has an optical zone, an outer periphery and a retention mechanism disposed on the outer periphery The optic is configured to be disposed in the inner zone of the platform and to extend to a location between the inner periphery and the outer periphery of the platform to be secured to the platform at the location The platform can be secured to an inner periphery of the eye or can be formed into a natural lens by cutting the lens using a laser or other energy source

Methods and apparatuses to increase intraocular lenses positional stability

High–Speed Optical Coherence Tomography for Post–Lasik Management

The invention refers to an ocular implant (10a,10b), which comprises: - an optical portion (11); and, - at least two polymer haptics (12a, 12b) for fixation of the ocular implant (10a, 10b) to tissue inside an eye; wherein at least one portion of the haptics (12a, 12b) contains a photoinitiating agent delivery means The invention also refers to a kit for implanting an ocular implant (10a, 10b) in an eye, the kit comprising an ocular implant (10a, 10b) comprising at least two polymer haptics; and additionally a photoinitiating agent for at least partially impregnating a first portion of the ocular element (10a, 10b) or a second portion of tissue in the eye; and, a light source for providing light of a wavelength adapted to excite the photoinitiating agent The invention further refers to a method for implanting such an ocular implant (10a, 10b) inside an eye

/pdf/photochemically-induced-engagement-of-intraocular-implants-av21box224.pdf

Photochemically induced engagement of intraocular implants

We present in this paper the quantification of the geometrical features of the anterior segment of the eye using Anterior Segment Optical Coherence Tomography (AS-OCT). This quantification was achieved by following our own developed methodology including the device development and their distortion calibration (Fan and refraction) for 3-D imaging, and automatic analysis tools as well. The stastistical comparison of the corrected topographies of the anterior cornea with topographies from state-of-the art clinical topography systems represents a valuable contribution toward the development "All-OCT-based" topographic systems. In addition, we first reported topographies of the crystalline lens in vivo, which is a promising tool to investigate the lens optical properties, the contribution of the lens to the overall retinal image quality, and understanding the change of the physical properties of the lens with accommodation and aging. Furthermore, our quantitative AS-OCT allowed the analysis of the keratoconic cornea and the changes produced by Intra Corneal Ring Segment (ICRS) treatment, as well as monitoring of the ICRS 3-D location. Finally, OCT-based biometry we present in this paper is a promising tool to investigate the changes after cataract surgery; the contribution of the (Intra Ocular Lens) IOL location and tilt to the overall retinal image quality, and in the design of new IOLs.

/pdf/quantitative-anterior-segment-optical-coherence-tomography-3o9z4ty4ib.pdf

Quantitative anterior segment optical coherence tomography

A method for determining an ophthalmic lens having unwanted astigmatism, the ophthalmic lens being adapted to a wearer, the method including: a wearer prescription data providing during which wearer prescription data indicative of an ophthalmic prescription of the wearer are provided; a wearer focal data providing during which wearer focal data indicative of the wearer preferred image focal plan are provided; an ophthalmic lens determining during which the ophthalmic lens is determined based on the prescription of the wearer and the wearer focal data to reduce impact of unwanted astigmatism of the ophthalmic lens for the wearer.

Method for determining an ophthalmic lens having unwanted astigmatism

OCT with air puff stimulus

The invention relates to a device (1) for measuring the optical power of an optical test system (4). The device (1) comprises an optical object generator assembly (2), a support (3) for the optical test system (4), a digital image detector (5), and a deflector assembly (6). The deflector assembly (6) is intended to generate a lateral movement in respect of the initial optical image (41), thereby producing a displaced optical image (61) and a reference optical image (60). The digital image detector (5) captures the displaced optical image (61) and the reference optical image (60) in at least one digital image (50) containing data relating to the lateral movement. The device (1) comprises processing means for calculating the optical power of the optical test system (4) from the data relating to the lateral movement. The invention also relates to a measurement method.

/pdf/device-for-determining-the-optical-power-of-lenses-and-2wnkeirdk7.pdf

Device for determining the optical power of lenses and measurement method

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