JPH0263016B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to improvements in intraocular lenses, particularly lenses for use in the anterior chamber of the eye.

This type of intraocular lens is used to compensate for the loss of the crystalline lens caused by cataract removal surgery, which is common in the elderly. Conventionally, a lens with a support arm is used to fix the lens in the eye, and the optical system is It has many advantages as a method to compensate for cataract surgery, and is highly regarded as a method that significantly contributes to not only social reintegration after cataract surgery but also daily life.

However, on the other hand, since lenses with intraocular support arms are inserted into the eye during cataract surgery, it is necessary to pay close attention to their adaptability to the eye disease and the insertion technique. support method,
In particular, there are still issues and constraints that remain in terms of adaptation, such as problems with the shape of the support arm for fixing the lens in the eye and foreign body expulsion, and countermeasures are strongly desired.

An object of the present invention is to provide an economical novel intraocular lens without a support arm, which significantly reduces the problems of conventional intraocular lenses with a support arm for fixing the lens in the eye. Another object of the present invention is to provide an intraocular lens of a novel design, which has a unique action that can avoid damage to ocular tissue and corneal scarring.

In other words, it is an object of the present invention to economically provide an intraocular lens of a completely new concept, which eliminates the need for the support arm of the conventional intraocular lens with a support arm.

That is, the gist of the present invention is to provide an intraocular lens that can be inserted into the anterior chamber humor of the anterior chamber cavity between the cornea and iris of the eyeball, and which It is a lens made of a transparent material with a specific gravity that is not much different from water's specific gravity of 1.0036 to 1.012, and the outer shape of the lens is circular or nearly circular with no support arms, and the lens diameter is the average diameter of the cornea. Width diameter 12mm, smaller than average vertical diameter 11mm
4.0 to 7.5 mm, and furthermore, the front surface of the lens has a curved surface with a radius of curvature smaller than the average radius of curvature of the corneal curved surface of the eyeball, 7.6 mm, and the rear surface is behind the surface formed by the periphery of the outer diameter of the lens. It is a lens that has a curved surface that does not protrude and has a curved surface or a raised part that does not affect the ocular tissue, and the lens has a curved surface that does not protrude into the eye.・When inserted (worn) into the anterior chamber volume (approximately 1% of the anterior chamber volume), the intraocular lens itself, which does not have the support arm, is subjected to a pressing force mainly caused by vertical and horizontal movements of the eyeball (approximately 1% of the anterior chamber volume). Water runoff rate: average 0.28±0.05μ/
min/mmHg) and the convective action of the anterior aqueous humor flowing down and up due to this pressing force and the thermal circulation of the aqueous humor, it is pushed toward the crystalline lens, and as a result, the intraocular lens is moved away from the posterior surface of the cornea and the anterior chamber A protrusion such as a clip for holding the iris on the lens itself, characterized in that the intraocular lens is made of a transparent material whose specific gravity is not much different from the specific gravity of the anterior aqueous humor so that it can be suspended and supported in the inner cavity. It is a floating type intraocular lens in the anterior chamber of the anterior eye, which does not have an object.

Conventionally, various known intraocular artificial lenses include, for example, US Pat. No. 4,261,065, US Pat.
As described in the specification of No. 3971073 or JP-A-52-39987 and JP-A-51-1511149,
It is known that artificial lenses are equipped with clips, support plates, and support arms for holding the iris. However, these artificial lenses with clips or support plates that clamp and fix the iris are large and heavy because the clips and support plates become protrusions, and require a great deal of support for eye surgery. It was unsuitable for women, women, and children, and some people felt strange or rejected it, so there was a strong demand for improvement.

The present invention is characterized by a floating intraocular lens of a novel concept, which is small in size, circular in appearance, and easy to operate, without having a clip or support plate protrusion on the lens itself for holding the iris.

In the present invention, the anterior chamber of the anterior chamber of the anterior eye segment is a gap that exists between the cornea and the iris and is filled with aqueous humor, and the gap filled with this aqueous humor, that is, the anterior chamber depth. averages 3.40 to 3.68 mm for normal-sighted individuals, 2.865 to 3.55 mm for hyperopic individuals, and 3.226 to 3.97 mm for myopic individuals. In the present invention, a lens is inserted into the anterior chamber to compensate for the loss of the crystalline lens caused by cataract removal surgery.
This lens has a specific gravity of human anterior aqueous humor of 1.0036 or
A transparent material that has a specific gravity similar to 1.012 and can be accommodated in the anterior chamber. A material with a high refractive index that can be used optically, such as a plastic such as transparent methylmethacrylic resin, acrylnitrine resin, silicone resin, or polyester resin. Preferably, the refractive power is standard, for example +20D to +40D (diopters). The shape of the lens of the present invention is such that it is maintained in a floating state within the anterior aqueous humor and forms a strong plano-convex or concave-convex lens together with the cornea, thereby optically assisting the visual acuity of patients with cataract surgery. Therefore, it is naturally desirable that the outer shape be circular or nearly circular, resembling the crystalline lens and anterior chamber, and this diameter should be approximately 10 to 10 mm in diameter on the average transverse diameter of the human cornea.
12mm, slightly smaller than the average vertical diameter of 9 to 11mm
A range of about 4.0 to 7.5 mm is ideal both optically and for the tissues of the eyeball.

The radius of human corneal curvature is an average of 7.5 to 7.8 mm in the front horizontal direction and 7.4 to 7.8 mm in the vertical direction.
7.7mm, surface power averages 42.84D to 45.5D, posterior surface averages 6.22 to 6.7mm, power -5.58D
It is.

In addition, the anterior surface of the lens of the present invention has a radius of curvature R that is approximately 8 mm, which is slightly larger than the average radius of curvature of the corneal curved surface, or is smaller than that.
For example, an important and novel feature of the present invention is that it is configured to have a curved surface of 6.5 mm, and that a lens support arm is not required. The rear surface of the lens faces the iris side and forms a smooth lens surface without any protrusions, so that it is optically configured to completely assist visual acuity.

The present invention is a floating intraocular lens that eliminates the need for a support arm attached to a conventionally known lens.Additionally, regarding the curvature surface of this lens, the circle formed by the scleral surface in a normal eye ( Diameter approx. 23
It has a disc shape with a curved surface that is approximately the same as the curved surface that is assumed to pass through the anterior chamber of mm), and the periphery is formed into a circle or ellipse (lateral diameter approximately 7.5 mm for people with large eyes) approximately close to the angle of the anterior chamber. do.

As a hydrodynamic experiment to understand the floating state of the floating intraocular lens of the present invention, a transparent closed cylinder (height 60 mm, diameter 20 mm) was prepared, and the cylinder was placed at a position corresponding to 1/4 of the cylinder diameter. A vertical partition wall was provided in the direction perpendicular to the cross section, and the cylinder was filled with water with a specific gravity of 1.0 to a depth of 50 mm. Soft contact lenses made of methyl methacrylic resin are the next most economical (curvature radius 7.5 mm, diameter 13.0 mm, depth
3.0mm, specific gravity 1.13) suspended in water with a float and string,
The overall specific gravity of soft contact lenses has been brought closer to 1.0. In this state, when the cylinder is gently shaken 60 times per minute with a lateral amplitude of 10 mm, the soft contact lens adheres to the septum while moving as if being pushed by the vertical septum, and even during the vibration of the cylinder, the soft contact lens hardly vibrates. During this time, it was clearly confirmed that the soft contact lens was in an upright position. As is clear from this model experiment, it was confirmed that the intraocular lens itself can float vertically within the anterior aqueous humor by the pushing force generated by vertical and horizontal movements of the eyeball.

In addition, as an example of a clinical trial related to the present invention, the inventor (Utsugi Ophthalmology Clinic, ophthalmologist, doctor of medicine) used rabbits and inserted an optical lens made of methyl methacrylic resin with a diameter of 4.5 mm into the anterior chamber of the rabbit's eye. As a result of observation for 3 days, it was confirmed that the turbidity of the anterior aqueous humor in the anterior chamber lumen disappeared and became clear, and the rabbit's behavior had become normal.

What is important for this trial example is that if the outflow of anterior aqueous humor (aqueous humor production is similar to that in humans) in the anterior chamber is normal, the lens in the anterior chamber can be inserted into the crystalline lens. As a result, the intraocular lens inserted into the anterior chamber cavity becomes floatingly supported in the anterior chamber cavity of the anterior segment of the eye.

If the outflow of anterior aqueous humor to the lens in the anterior chamber is not normal, the intraocular lens inserted into the anterior chamber will come into contact with the curved surface of the cornea, and the anterior aqueous humor will begin to become cloudy and form a suspension. It is a remarkable fact that this will be the case.

Therefore, as mentioned above, the fact that the anterior aqueous humor became transparent after surgery (lens insertion) is considered to be evidence that the clinical trial was successful.

In addition, the American medical journal AmJ
Ophthalmol 107: 659-663, 1989, the Japanese medical journal "Clinical Ophthalmology" Vol. 43, No. 11, p. 1682 (Article introducer: Katsura, Hiroshi, Department of Ophthalmology, Keio University, University of Auckland) states, The article is titled "Correction of Myopia by Implantation of Artificial Lens into the Lens Eye" and is introduced as follows. (The artificial crystalline lens introduced in this document corresponds to the intraocular lens in the case of the present invention.) {34 cases (humans) In 62 phakic eyes, Worst , implanted with iris clawlens. Patients with gastric ulcers or diabetes were also excluded because large doses of steroids were administered postoperatively. Cases with a corneal endothelial cell density of 3000 to 4000/mm ² were selected. As for postoperative complications, iritis was common in early cases, but it decreased with improved surgical techniques and steroid administration. There was only one case in which the artificial lens was removed postoperatively, and this was a case in which the author's intraocular pressure increased and irreversible pupil dilation occurred due to insufficient removal of hyaluronic acid. No lens contact with the cornea or cataract was observed. After an average follow-up of 11 months, the corneal endothelial cell density remained at its preoperative state except for two cells, which decreased to 1500/mm ² . Best-corrected visual acuity improved in 50 of 62 eyes and remained unchanged in 11 eyes. The postoperative refraction was compared with the preoperative expected value.
Thirty-nine eyes (63%) had a difference of less than 1 diopter, and only 4 eyes (6.5%) had a difference of 2 diopters or more.
Based on these results, it was considered possible to perform the surgery without excessive risks or serious complications. However, this surgery should be considered in cases where contact lenses cannot be worn, or glasses cannot be worn due to occupational or psychological reasons, and where correction cannot be achieved with radial corneal incision. . } As described above, in the United States, where there are relatively fewer restrictions on eye surgery than in Japan, there have been clinical trials of intraocular lenses for the anterior chamber of the anterior segment of the eye as described above after the publication of the present invention. It is truly remarkable that 62 eyes came to exist.

There is no need to explain the joy and change in outlook on life that occurs when people on the verge of blindness are given light through intraocular lens surgery (a clinical trial example) in the anterior chamber of the anterior segment of the eye. Therefore, it is considered that such an invention should be highly evaluated for its industrial effects.

Embodiments of the intraocular lens of the present invention will be described below with reference to the accompanying drawings. The first is a sectional view showing an embodiment of the floating intraocular lens of the present invention, and the second is a cross-sectional view showing the embodiment of the lens shown in FIG. This is an explanatory horizontal cross-sectional view of the entire eyeball when inserted into the inner cavity of the anterior chamber of the eye, and the anterior chamber 4 of the anterior eye and the crystalline lens 5 are located between the cornea 2 and the vitreous body 3 of the eyeball 1. Most of the crystalline lens 5 has actually disappeared from this figure 2 (see figure 3) due to cataract removal surgery, but it is normal.
Conventionally, a heavy glass or plastic lens with a supporting arm is inserted in place of the crystalline lens 5 that has been lost due to removal surgery, but in the present invention, a lens with a support arm made of heavy glass or plastic is inserted in place of the crystalline lens 5 that has been lost due to removal surgery. Focusing on the convective action of aqueous humor (specific gravity 1.0036 to 1.012), a lens 10 having a diameter of about 5.0 mm and without a support arm as shown in FIG.
The front surface 11 of this lens 10 has a radius of curvature R
Transparent acrylnitrile lens 1 with a thickness of approximately 0.6 mm and a curved surface of approximately 6.5 mm (rear radius of curvature 100 mm)
0 (specific gravity adjusted to 1.007) is inserted and suspended. In this case, by forming the rear surface of the lens 10 smoothly, favorable results can be obtained both in terms of floating effect and optically.

The present invention provides a method for discharging the anterior chamber of the anterior chamber into the anterior aqueous humor of the inner cavity of the anterior chamber 4 of the anterior eye (anterior aqueous humor normally gushes out at a production rate of about 3μ/min, equivalent to about 1% of the anterior chamber volume). specific gravity of water
Specific gravity 0.950 to 1.0036 or 1.012 with no significant difference
A lens made of a transparent material having a specific gravity adjusted between 1.180 and 1.180 is inserted, and the outer shape of the lens is a circle without a support arm or an elliptical shape close to a circle, and the front surface 11 of the lens has a cornea of the eyeball. When a curved surface similar to the curved surface is provided, the intraocular lens 10 inserted into the anterior aqueous humor has a pressing force that is corrected mainly by vertical and horizontal movements of the eyeball (aqueous humor outflow rate/average of an eye with normal intraocular pressure). 0.28±0.05μ/min/mmHg) and by the action of this pressing force and thermal circulation (the intraocular lens 10 itself having a curved surface) is pushed toward the crystalline lens 5 (this lens 5 is actually removed during cataract extraction surgery). Shape disappeared from Figure 2 (see Figure 3)
Therefore, when the crystalline lens 5 is removed, the iris 6 is pushed toward the vitreous body 3 by the pressure of the anterior aqueous humor in the anterior chamber 4, while the transparent sol of the vitreous body 3 itself The anterior chamber 4 and the vitreous body 3 bulge toward the iris 6 side, and the anterior chamber 4 and the vitreous body 3 form a newly inserted intraocular lens 10 of the present invention, which will be described later. Fourth
(see figure), this will result in good harmony. ) As a result, the intraocular lens 10 is floatingly supported in the anterior chamber cavity while being moved away from the posterior surface of the cornea 2. Based on the new findings, the eye does not have a support arm with a new configuration. This led to the creation of the internal lens 10.

In other words, the eyeball 1 constantly repeats vertical and horizontal movements except during sleep, and naturally when a lens is inserted into the eyeball, the lens also makes vertical and horizontal movements, but at that time, the front surface 11 of the lens 10 When a curved surface exists, the intraocular lens 10 existing in the anterior chamber 4 is affected by the pressing force generated by the upward and horizontal movement of the eyeball and by the thermal circulation of the aqueous humor.
This results in a force constantly pushing the body backwards. In this case, even if the force pushing the lens 10 toward the crystalline lens due to the convective action of the anterior aqueous humor flowing down and upstream due to the thermal circulation of the aqueous humor in the anterior chamber 4 is small,
Since there is almost no difference between the specific gravity of the anterior aqueous humor of 1.0036 to 1.012 and the specific gravity of the lens 10 of 0.950 to 1.180, the lens 10 is ultimately supported so as to almost float within the anterior aqueous humor in the anterior chamber 4 due to the convection action. That's what happens.

In order to make the floating effect more effective and to maintain the center optically, it is best to have a gently smooth surface on the iris side of the rear surface of the lens 10.

According to the configuration of the intraocular lens 10 of this example,
The pressing force generated by vertical and horizontal movement of the eyeball effectively acts on the curved surface provided on the front surface 11 of the lens 10, which has a radius of curvature R smaller than the radius of curvature of the corneal curved surface, and does not constantly push the intraocular lens 10 backward. A force (in the direction of the arrow in the drawing) that causes the lens 10 to float in the anterior chamber 4 and pushes it backward acts (in the direction of the arrow in the drawing), and as a result, the lens 10 is moved away from the posterior surface of the cornea 2 to avoid damage to the cornea 2 caused by the intraocular lens. The intraocular lens 10 can be expected to have a unique effect of exhibiting a sufficient optical effect.

According to the intraocular lens configured according to the present invention,
In particular, as an intraocular lens for the anterior chamber of the anterior eye of patients who have undergone cataract removal, it is optically supported in a floating state within the anterior chamber, and has a support arm to fix the lens within the eye. This allows us to provide an extremely ideal intraocular lens that avoids damage to the cornea due to intraocular lens insertion, and the lens itself can be manufactured easily to suit the patient's symptoms. Its unique feature is that it can greatly contribute to preventing amblyopia and restoring visual acuity in patients with cataract eyes.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a floating intraocular lens showing an embodiment of the present invention, and Fig. 2 is an explanatory diagram of the embodiment when the intraocular lens of Fig. 1 is inserted into the anterior chamber cavity of the anterior segment of the eye. In the figure, 1 is an eyeball, 2 is a cornea, 3 is a vitreous body, 4 is an anterior chamber, 5 is a crystalline lens, 6 is an iris, 10 is an intraocular lens, and 11 is a curved front surface of the lens 10. , R is the radius of curvature. FIG. 3 is an explanatory diagram of an eyeball in which the crystalline lens 5 affected by cataract has been surgically removed. FIG. 4 is an explanatory diagram when the intraocular lens 10 of the present invention is inserted into the anterior chamber 4 after the crystalline lens 5 has been extracted.

Claims (1)

[Scope of Claims] 1. An intraocular lens that can be inserted into the anterior chamber humor of the anterior chamber between the cornea and iris of the eye, which has a specific gravity of 1.0036 to 1.0036. It is a lens made of a transparent material with a specific gravity that is not much different from 1.012, and the outer shape of the lens is circular or nearly circular without a support arm, and the lens diameter is 12 mm, the average transverse diameter of the cornea, and the average diameter of the lens. The lens has a vertical diameter of 4.0 to 7.5 mm, which is smaller than 11 mm, and the front surface of the lens has a curved surface with a radius of curvature smaller than the average radius of curvature of the corneal curved surface of the eyeball, 8 mm, and the rear surface is formed by the periphery of the outer diameter of the lens. A lens that has a curved surface that does not protrude rearward from the surface that is attached to the eye, and that does not have a support arm that exhibits a shape that does not affect the ocular tissue, and that the lens has a curved surface that does not protrude rearward from the surface that is When inserted into the intraocular lens itself (water production rate of approximately 3μ/min, approximately 1% of the anterior chamber volume), the intraocular lens itself exerts a pressing force (aqueous humor in an eye with normal intraocular pressure) mainly caused by vertical and horizontal movements of the eyeball. Outflow rate/average 0.28±0.05μ/min/mmHg)
Due to the convective action of the anterior aqueous humor flowing down and up due to this pressing force and thermal circulation, the intraocular lens having a curved surface is pushed toward the area where the crystalline lens is. The intraocular lens is made of a transparent material whose specific gravity is not much different from that of the anterior aqueous humor so that it can be supported floating in the anterior aqueous humor in the anterior chamber cavity in a state away from the posterior surface. An intraocular lens that floats in the anterior chamber of the anterior eye and does not have any protrusions such as clips that hold the iris on the lens itself. 2 Specific gravity in the anterior chamber of the anterior chamber of the anterior eye segment: 1.0036 or more
Claim 1, which does not have a support arm, is made of a plastic lens, such as methyl methacrylic resin, acrylonitrile resin, or polyester resin, as a transparent lens material having a specific gravity of 0.950 to 1.180, which is not much different from 1.012. Floating intraocular lenses as described in Section. 3. The outer shape of the lens is circular or approximately circular without a support arm, and has a curved surface on the front surface with a radius of curvature that is close to or smaller than the radius of curvature of the curved surface of the cornea, and the rear surface is close to the eye. The floating intraocular lens according to claim 1, characterized in that it has a curved surface that does not affect tissue. 4. A lens made of transparent plastic material such as methyl methacrylic resin or acryl nitrile resin, with a circular or nearly circular outer shape without a support arm, and a diameter of 4.0 to 7.5 mm.
A floating intraocular lens according to claim 1, comprising an optical lens. 5. When the lens is inserted (attached) into the anterior chamber of the anterior eye, the intraocular lens, which does not have a support arm, is exposed to the pressing force mainly caused by vertical and horizontal movements of the eyeball (aqueous humor outflow in eyes with normal intraocular pressure). Rate/Average 0.28±0.05μ/
min/mmHg), the intraocular lens is pushed toward the crystalline lens by the convective action of the anterior aqueous humor flowing down and up due to the pressing force and thermal circulation, and as a result, the intraocular lens is moved away from the posterior surface of the cornea. Claim 1, wherein a curved surface with a radius of curvature that is close to or smaller than the radius of curvature of the curved surface of the cornea of the eye is provided on the front surface of the lens to provide the function of being suspended and supported in the anterior chamber lumen. Floating intraocular lenses as described in Section. 6. An optical lens whose external shape is circular or approximately circular without a support arm, where the central part of the lens is formed into a hollow part as necessary, and the air part is used as a part of the optical lens. A floating intraocular lens according to claim 1, characterized in that the floating intraocular lens comprises: