NL2023876A - Method for customizing and evaluating accommodating intraocular lens - Google Patents

Abstract

The invention relates to a method to customize accommodating intraocular lenses, by optical coherence tomography, OCT images, which images provide multiple sets 5 of multiple ocular parameters including the diameter of the ciliary mass during accommodation prior to implantation, also: ‘pre-op’, and after implantation, post-op. The pre-op images provide the required diameter, the required fixed optical power and the required accommodative amplitude of the lens. The post-op images provide evaluation of correction of the aphakic refractive error and accommodation 10 for near vision.

Description

METHOD FOR CUSTOMIZING AND EVALUATING ACCOMMODATING INTRAOCULAR LENS

Summary

Method to customize accommodating intraocular lenses, by optical coherence tomography, OCT images, which images provide multiple sets of multiple ocular parameters including the diameter of the ciliary mass during accommodation prior to implantation, also: ‘pre-ορ’, and after implantation, post-op. The pre-op images provide the required diameter, the required fixed optical power and the required accommodative amplitude of the lens. The post-op images provide evaluation of correction of the aphakic refractive error and accommodation for near vision.

Text

Intraocular lenses, lOLs, replace the natural lens of the eye of which the natural lens is removed due to, for example, cataract, due to extreme myopia or due to presbyopia. Monofocal lOLs only restore far vision and do not restore near vision, vision at reading distance resulting in spectacle dependence. Multifocal lenses do restore, to a degree, also near vision, by increasing optical blur and so reducing contrast sensitivity.

Accommodative intraocular lenses, AIOLs, change diopter power of the lens to adjust for sharp vision from far to near, as in, for example, the AkkoLens Lumina lens, of which clinical results are reported in, for example, Alió et al, in the prior art documents such as Am J Ophthalmol 2016 164: 37-48 and J Refract Surg. 34(2): 78-83 and references mentioned therein, and the optical and mechanical principles reported in, for example, but not restricted hereto, in NL2012133, NL201242, EP1871299, EP1932492, US2009062912, W02005084587, US2014074233, WO2014058316, EP2765952, NL2012257278, US2010131955, US2010106245 and NL1029548 and references to other documents made therein, all of which documents are considered to be part of the present document.

Fitting of accommodative lenses to a particular eye requires precise correction of fixed optical power, the optical power required to correct for refractive error of the aphakic eye, and accommodative amplitude, the variable optical power for intermediate and near vision. Said precision is required of an AIOL because post implant, post-op, need for spectacles is undesirable. So, firstly, the AIOL must provide, in the disaccommodated state, the resting state, the required lens power for sharp distance vision, emmetropia, and that, secondly, the AIOL must provide a gradual increase in lens power, accommodation, for sharp vision from far to near.

The present invention, this document, discloses a method, by any imaging procedure of the eye, for example, any optical coherence tomography, OCT, or, alternatively, any ultrasound imaging procedure, to customize an accommodative intraocular lens, also: ‘lens’, for a particular eye. OCT will be the procedure to illustrate the method in the present document. The method provides multiple sets of pre-operative ocular parameters measured during accommodation of the eye. These sets include the diameter of the ciliary mass, the diameter of the ocular sulcus, and the diameter of the pigment layer of the iris. At least one set of measurements provides said parameters for the disaccommodated eye and another set includes measurements of said parameters for the accommodated eye. More sets can be obtained measuring said parameters of at least one intermediate accommodative state to evaluate said graduation in accommodative power, for example, a set at intermediate distance.

Also, the method can provide additional ocular parameters including corneal parameters K1 and K2 and the variation of corneal parameters K1 and K2 over the circumference of the cornea, the depth of the anterior chamber, the depth of the posterior chamber and the position of principal plane of the natural lens. These additional ocular parameters can provide, pre-op, customization of the required lens power of the AIOL for far vision, the power required to correct refraction of the aphakic eye. Also, the additional ocular parameters can pre-op, customization of the required lens toric correction of the AIOL, or, alternatively, provide, post-op, evaluation of the resulting lens power for far vision and can, post-op, provide evaluation of the resulting toric correction. So, all optical measurements, lens fitting and subsequent lens evaluation can be provided by a few OCT examinations which examinations are rapid, non-intrusive and therefore inexpensive to carry out.

The desired lens diameter, the lens sizing, depends on the diameter of the ciliary mass, or, alternatively, on the diameter of the sulcus, or, alternatively, on the diameter of the pigment layer. Note that an overly large lens results in accommodation at the resting state, at the state of vision at far, which, in turn, results in a myopic eye. An overly small lens results in proper distance vision but also in loss of accommodative power because of slack at the start of the accommodative process.

The lens accommodative power, as in the AkkoLens Lumina, depends on the difference between the diameter of the ciliary mass in the disaccommodated state and the accommodated state because the ciliary mass drives the change in optical power of the lens. Adjustment of the accommodative power of the lens can be achieved by, firstly, increasing or decreasing the slope of the cubic surfaces of the AIOL, meaning: changing optical power of the lens at a given change in amplitude of the ciliary mass, or, alternatively, increasing the elastic property of the hinge of the AIOL, meaning: increasing the force required for a given change in optical power.

Figures

Figure 1. Digitally enhanced and inverted OCT image of the disaccommodated eye of a young person with the ciliary mass, C, the sulcus opening, S, the the pigment layer, P, and the sulcus diameter, SD. Note that the ciliary mass is retracted backward, in posterior direction, which fully opens the sulcus. The sulcus base is defined by the continuation of the iris pigment layer. The diameter of the ciliary mass is at its widest, the natural lens is flattened and the eye is focused at far.

Figure 2. Digitally enhanced and inverted OCT image of the same eye as in Fig. 1, but accommodated. Note that the ciliary mass, C, is contracted inward and upward, in anterior direction, and is compressed against the iris, that the sulcus base, SB, largely disappeared and can only be deducted from the end of the pigment layer, P, and that the sulcus opening, S, has moved inward by, I this example, approximately 0,3mm per side which thus reduces the cilairy diameter, CD, by approximately 0,6mm. The diameter of the ciliary mass is at its most narrow, the natural lens is relaxed and the eye is focused at near.

The method disclosed above allows customization of a properly sized AIOL with the required accommodative power for a particular eye. However, additionally, the OCT can provide measurement of corneal optical power, corneal asphericity and corneal toricity, and the anterior chamber depth and posterior chamber depth. From these measurements the required power of the lens for far vision, optical power at the resting state, can be calculated.

Note that, especially in eyes with an opaque lens due to advanced cataract the amplitude of movement of the ciliary mass can be hampered. For such eyes the accompanying eye can be measured to estimate ciliary amplitude which amplitude is generally comparable to the eye to be treated.

So, in summary, the method in the present document discloses a method to customize and evaluate an accommodative intraocular lens, by optical coherence tomography with the method providing at least two sets of primary ocular parameters. At least one set is obtained during disaccommodation and at least one same set is obtained during accommodation of the eye. The sets comprise a combination of measurements including the diameter of the ciliary mass, the diameter of the ocular sulcus and the diameter of the pigment layer of the iris.

The method also provides additional ocular parameters which include, but not restricted to, additional ocular parameters including the corneal parameters K1/K2 over the circumference of the cornea, the depth of the anterior chamber and the depth of the posterior chamber and the position of principal plane of a lens.

The method is provides the required lens diameter for the required lens power at the lens resting state, meaning: the lens power required to correct the refractive error of the aphakic eye, with the required lens diameter depending on at least one primary parameter.

The method also provides the required lens accommodative power with the lens accommodative power depending on the difference between the diameter of at least one said primary parameter in the disaccommodated state and the accommodated state.

Additionally, the method provides, pre-op, the required lens power for correction of the refractive error of the aphakic eye with the required lens power depending on a combination of the additional parameters, and/or, provides, pre-op, a combination of the required lens power for correction of toric error of the eye and toric angle with said power and angle depending on a combination of the additional parameters.

Furthermore, the additional ocular parameters provide, post-op, evaluation of the required lens power for correction of the refractive error, the refractive outcome, and/or, the additional ocular parameters provide, post-op, evaluation of the resulting combination of toric power and angle, the toric outcome.

The method provides an accommodative lens to provide correction of the refractive error of the aphakic eye, any toric optical error of the eye and accommodation of the eye into which the lens is implanted.

Claims (12)

Conclusions Method of setting and evaluating an accommodative intraocular lens by any imaging procedure of the eye, characterized in that the method is adapted to provide at least two groups of primary ocular parameters, with at least one group obtained during disaccomodation and at least one group obtained during accommodation, the groups comprising a combination of measurements including the diameter of the ciliary mass, the diameter of the ocular sulcus, the diameter of the pigment layer of the iris and additional ocular parameters. A method according to claim 1, characterized in that the method is adapted to provide the required lens diameter for the required lens power in the lens rest position, indicating the lens power required to correct the refractive error of the aphakic eye wherein the required lens diameter depends on at least one primary parameter. A method according to claim 1, characterized in that the method is adapted to provide the required accommodative lens power wherein the accommodative lens power depends on the difference between the diameter of at least one said primary parameter in the disaccomoded state and the accomodated state. Method according to any one of claims 1 to 3, characterized in that the method is adapted to provide groups of additional ocular parameters, including the corneal parameters K1 / K2 about the circumference of the cornea, the depth of the anterior chamber and the depth of the posterior chamber and the position of the major plane of a lens. A method according to claim 4, characterized in that the method is adapted to provide, prior to surgery, the required lens power for correction of the refractive error of the aphakic eye, the required lens power depending on a combination of the additional parameters . A method according to claim 5, characterized in that the method is adapted to provide, prior to surgery, a combination of the required lens power for correction of a toric error of the eye and toric angle, wherein said force and angle depend on a combination of the additional parameters. A method according to claim 6, characterized in that the method is adapted to provide, after surgery, an evaluation of the lens power for correction of the refractive error, the refractive result. Method according to claim 7, characterized in that the method is adapted to provide, after surgery, an evaluation of the combination of toric force and angle, the toric result. Method according to any combination of claims 1-8, characterized in that the method comprises optical coherence tomography. A method according to any combination of claims 1-8, characterized in that the method comprises an ultrasound imaging procedure. Method according to claims 9-10, characterized in that the method comprises any combination of optical coherence tomography and an imaging procedure by ultrasound. Accomodative lens adjusted by a method according to claims 1 - 11, characterized in that the lens is adapted to provide a correction of the refractive error of the aphakic eye, some toric error of the eye and restoration of accommodation of the eye in which the lens is implanted.