JPH0380500B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an intraocular lens used in surgery for cataracts and the like.

[Prior Art] During cataract surgery, after the nucleus in the crystalline lens is delivered, an intraocular lens, which is an artificial crystalline lens, is inserted into the posterior chamber to correct visual acuity.

However, corneal astigmatism occurs due to changes in the shape of the cornea due to incisions made in the sclerocorneal region during surgery, suturing with nylon threads, and the like. For example, when nylon threads are used for suturing, the degree of corneal astigmatism that occurs increases after 3 months after surgery.
There are reports that the amount is 0.5 Diopter (hereinafter referred to as (D)) or more.

In addition, this value of corneal astigmatism is the degree of astigmatism that occurs due to surgery, and in the case of patients who already have astigmatism due to a disease etc. before surgery, the strength of astigmatism after surgery is determined by the degree of astigmatism caused by surgery. It can be considered that it is approximately equal to the sum of the strength of astigmatism that occurs and the strength of astigmatism before surgery.

Therefore, in order to correct this astigmatism, glasses or hard contact lenses (hereinafter referred to as
Astigmatism is corrected by using corneal incisions (HCL) or by surgical techniques such as corneal incisions.

[Problem to be solved by the invention] However, it is difficult to correct astigmatism of 3(D) or more with glasses or HCL, and it is difficult to correct astigmatism of 3(D) or more.
Wearing the HCL has become uncomfortable for patients.

Furthermore, the following problems exist regarding the corneal incision method.

Once a corneal incision or corneal suture is performed during cataract surgery, it is difficult to perform the surgery again on the same location.

Because the cornea is intentionally scarred, there is a possibility of corneal infection.

Irregular astigmatism may occur.

In addition to cataract surgery, it becomes necessary to perform a new surgery called corneal incision, which is painful for the patient.

Injury to healthy corneas is considered ethically problematic.

The degree of astigmatism varies from patient to patient, but
Correction by the surgeon relies on sensory techniques, and it may not be possible to completely correct astigmatism.

For the above reasons, a method of correcting astigmatism by making a corneal incision is not generally performed.

Therefore, it has been proposed to try to correct astigmatism using the intraocular lens itself (Japanese Patent Application Laid-open No.
64-58253).

In this intraocular lens, the optical part is formed of an elastic optical material, a tightening member is provided around the outer periphery of the optical part, and the tightening amount can be adjusted by heating part or all of this tightening member with laser light, etc. By providing the portion, the radius of curvature of the lens surface can be substantially changed. For this reason, it is possible to correct the refractive power during and after surgery, correcting errors in the refractive power of the intraocular lens to be inserted that were measured before surgery and refractive errors including corneal astigmatism that slightly changed due to surgery. It is something that can be done.

By the way, when using a spherical intraocular lens to correct astigmatism, it is necessary to insert the intraocular lens with its axis of astigmatism completely determined relative to the direction of the patient's eyeball during surgery.

However, with an intraocular lens as described above, the position of the astigmatic axis cannot be accurately determined just by looking at the optical part, and the direction of insertion may be deviated.

[Object of the Invention] In view of the above-mentioned problems, the present invention provides a method for accurately and easily determining the direction of the astigmatic axis even during surgery, and for setting the direction during the manufacturing process of intraocular lenses. The present invention provides an intraocular lens that does not require a special manufacturing method.

[Means for Solving the Problems] The intraocular lens according to claim 1 of the present invention comprises an optical part made of an aspherical lens for correcting astigmatism, and a fixing part for holding the optical part within the eye. The planar shape of the optical part is approximately circular, two positioning holes are provided at symmetrical positions with respect to the center point of the optical part, and the astigmatism axis is set between the two positioning holes. It is something.

The intraocular lens according to claim 2 of the present invention comprises an optical part made of an aspherical lens for correcting astigmatism and a fixing part for holding the optical part within the eye, and the planar shape of the optical part is approximately It is circular, and has two positioning holes at symmetrical positions with respect to the center point of the optical section, and the astigmatism axis is shifted by 90 degrees from the axis connecting the two positioning holes, and It is set so that it passes through the center point.

The intraocular lens according to claim 3 of the present invention comprises an optical part made of an aspherical lens for correcting astigmatism and a fixing part for holding the optical part within the eye, and the planar shape of the optical part is approximately The optical part is circular, and the optical part is provided with a pair of fixing parts, and the attachment parts of the pair of fixing parts to the optical part are provided at symmetrical positions with respect to the center point of the optical part, and the astigmatism axis is set between the two attachment parts. It was set in between.

The intraocular lens according to claim 4 of the present invention comprises an optical part made of an aspherical lens for correcting astigmatism and a fixing part for holding the optical part within the eye, and the planar shape of the optical part is approximately The optical part is circular, and the optical part is provided with a pair of fixing parts, and the attachment parts of the pair of fixing parts to the optical part are provided at symmetrical positions with respect to the center point of the optical part, and the astigmatism axis is set between the two attachment parts. It is set so that it is offset by 90 degrees from the axis connecting the two and passes through the center point of the optical section.

[Operation] In the intraocular lens according to claim 1 of the present invention, since the astigmatism axis is set between the two positioning holes, the direction of the astigmatism axis can be easily determined, and the astigmatism can be corrected during surgery. The direction of the axis will not shift.

In the intraocular lens of claim 2, the astigmatism axis is set at a position 90° shifted from the axis between the two positioning holes, so the direction of the astigmatism axis can be easily determined, and it can be easily determined during surgery. The direction of the astigmatism axis will not shift.

In the intraocular lens according to claim 3, since the direction of the astigmatism axis is set between the attachment parts of the fixing part, the direction of the astigmatism axis can be easily and accurately determined, and the astigmatism can be corrected during surgery. There is no wrong direction of the axis.

In the intraocular lens according to claim 4, the direction of the astigmatism axis is set at a position 90° shifted from the axis between the attachment parts of the fixing part, so that the direction of the astigmatism axis can be easily and accurately determined. This allows the astigmatism axis to be misdirected during surgery.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

Reference numeral 10 is a shearing type intraocular lens made of a polymer compound such as PMMA (polymethyl methacrylate), which has an optical part 12 made of an aspherical lens and a part protruding from the opposing parts of the optical part 12. It consists of J-shaped fixing parts 14, 14. 16, 16 are positioning holes.

Aspherical lens power S(D) of the optical section 12 with the above configuration
is determined as follows.

The corneal astigmatism power of the patient before cataract surgery is measured, and the corneal astigmatism power G (D) is the sum of the measured corneal astigmatism power and the corneal astigmatism power generated by the surgery.
Calculate.

Using equation (), the astigmatic power G is converted into the power C(D) of the cylindrical lens required for the aspherical lens.

C=G×A...() However, A is the conversion ratio between the extraocular lens power and the intraocular lens power according to the Sanders-Retzlaff-Kraff formula (SRK formula). Although the value of A varies depending on the individual, it generally takes a value of 1.2 to 1.7.

Next, the power S'(D) of the conventional intraocular lens, which is only a spherical lens, is calculated using equation ().

S′=116.5−2.5×L−0.9×K () where L is the axial length (mm) of the patient into whom the intraocular lens 10 is inserted, and K is the corneal refractive power (D) of the patient.

Next, the aspherical lens power S is determined by substituting S' and C obtained above into the equivalent spherical equation ().

S=S'-C/2...() The aspherical lens determined above is attached to the optical part 12.
An intraocular lens 10 is manufactured as follows. Then, the intraocular lens 10 may be inserted into the patient through surgery.

For example, in the case of a patient whose direct astigmatism was 3 (D) according to corneal refractive measurements before cataract surgery, to reduce the total astigmatism to 0 (D) after 3 months after surgery. The aspherical lens power S of the intraocular lens 10 inserted into the lens is determined as follows.

First, the patient's axial length L and corneal refractive power K are measured in advance. For this patient, L=
23.2, K=44.

Assume that 0.5 (D) of direct astigmatism occurs due to surgery 3 months after surgery. Then, as mentioned above, including the 3(D) direct astigmatism before surgery, the total is 3.5(D).
It is necessary to correct direct astigmatism using the intraocular lens 10.

The power of the cylindrical lens is C is 4.375 according to the formula ().
(D) or approximately 4.5(D). However, A=1.25.

Substituting L=23.2 and K=44 into equation (), we get
S′=19.

When S is determined by substituting S'=19 and C=-4.5 into equation (), S=21.25.

Therefore, the aspherical lens power S required for this case is +21.25(D), and the required cylindrical lens power C is -4.5(D)Ax180°.

In addition, it is generally written as follows.

S+21.25D=C-4.5DAx180° The axis of the aspherical lens is set in the positioning holes 16, 16 in FIG. 2 and 3 show an example of an aspherical state of the optical section 10, which is an aspherical lens. FIG. 2 shows an end view taken along the line - in FIG. shows a - line end view in FIG.

The intraocular lens 10 with the astigmatic power S set as described above is inserted using the same surgical method as the conventional one. The intraocular lens can be inserted by, for example, a compression method, a dialing method, or a closed procedure. In this case, in order to correct direct astigmatism, the aspheric lens is inserted with its axis, that is, the positioning holes 16, 16 horizontal. In this case, since the axis of the aspherical lens is set in the positioning holes 16, 16, the aspherical lens can be inserted reliably and easily even during surgery without erroneous direction. FIG. 4 shows the state after the intraocular lens 10 has been inserted, and the upper part of the drawing is the patient's head. Note that 18 indicates the scleroneal region, and 20 indicates the anterior capsule.

As a result, the intraocular lens 10 inserted into the posterior chamber
In this case, the fixing parts 14, 14 are cicatrically fixed in the ciliary sulcus or between the anterior capsule and the posterior capsule at the equatorial region of the crystalline lens.
Therefore, the optical section 10 permanently maintains its position at the insertion site without rotating or moving.

Therefore, the axis of the aspherical lens is fixed, and direct astigmatism caused in the patient by the aspherical lens can be corrected. Therefore, there is no need to wear glasses or HCL after surgery as in the past, and there is no pain or discomfort to the patient. It also has the effect of correcting astigmatism that the patient already had due to a disease or other reason before the surgery. Furthermore, unlike conventional corneal incision methods, this method has the effect of reliably correcting the desired degree of astigmatism.

In the above embodiment, the axis of the aspherical lens is set at the positioning hole, but in the case of a non-hole intraocular lens, the axis is set at the base of the fixing parts 14, 14 instead. Even during surgery, it can be inserted reliably and easily without erroneous direction.

Further, although the above-mentioned intraocular lens 10 is a shearing type, the effect of the present invention is still sufficient even if an aspherical lens is used in the optical part of other posterior chamber lenses and anterior chamber lenses such as piercing lenses instead. can be obtained.

Further, in this embodiment, an intraocular lens made of a PMMA plastic lens is shown, but an intraocular lens such as a silicone lens may be used instead.

[Effects of the Invention] In the intraocular lens according to claim 1 of the present invention, since the axis of the aspherical lens, that is, the astigmatic axis is set between the positioning holes, the astigmatic axis can be reliably and easily adjusted even during surgery. You can insert it in the correct direction.

In addition, manufacturing is easy because there is no need to make the intraocular lens into a special shape or provide a mark to set its direction.

In the intraocular lens according to claim 2 of the present invention, the axis of the aspherical lens, that is, the astigmatic axis, is set to be shifted by 90 degrees from the axis connecting the positioning holes.
It can be inserted reliably and easily even during surgery without erroneously oriented the astigmatic axis.

In the intraocular lens according to claim 3 of the present invention, since the axis of the aspherical lens, that is, the astigmatic axis is set at the attachment part of the fixing part, the direction of the astigmatic axis can be reliably and easily misdirected even during surgery. It can be inserted without any problem.

In addition, manufacturing is easy because there is no need to make the intraocular lens into a special shape or provide a mark to set its direction.

In the intraocular lens according to claim 4 of the present invention, the axis of the aspherical lens, that is, the astigmatic axis, is set to be offset by 90 degrees from the axis connecting the attachment part of the fixation part, so that it can be reliably and easily adjusted even during surgery. It can be inserted without making a mistake in the direction of the astigmatism axis.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is an end view taken along the - line in FIG. 1, FIG. 3 is an end view taken along the - line in FIG. 1, and FIG.
FIG. 2 is a plan view of an intraocular lens inserted into the posterior chamber. Explanation of symbols: 10...Intraocular lens, 12...Optical section, 14...Fixing section.

Claims (1)

[Scope of Claims] 1. In an intraocular lens consisting of an optical part made of an aspherical lens for correcting astigmatism and a fixing part for holding the optical part within the eye, the planar shape of the optical part is approximately circular. An eye, characterized in that two positioning holes are provided at symmetrical positions with respect to the center point of the optical part, and the astigmatism axis is set on the axis connecting the two positioning holes. inner lens. 2. In an intraocular lens consisting of an optical part made of an aspherical lens to correct astigmatism and a fixed part to hold the optical part within the eye, the planar shape of the optical part is approximately circular, and the positioning Two holes were provided at symmetrical positions with respect to the center point of the optical section, and the astigmatism axis was set to be offset by 90 degrees from the axis connecting the two positioning holes and to pass through the center point of the optical section. An intraocular lens characterized by: 3. In an intraocular lens consisting of an optical part made of an aspherical lens for correcting astigmatism and a fixed part for holding the optical part within the eye, the planar shape of the optical part is approximately circular, and the optical part has a substantially circular planar shape. A pair of fixing parts are provided, the attachment parts of the pair of fixation parts to the optical part are provided at positions symmetrical about the center point of the optical part, and the astigmatism axis is set on the axis connecting the two attachment parts. An intraocular lens characterized by: 4. In an intraocular lens consisting of an optical part made of an aspherical lens for correcting astigmatism and a fixed part for holding the optical part within the eye, the planar shape of the optical part is approximately circular, and the optical part has a substantially circular planar shape. A pair of fixing parts are provided, the attachment parts of the pair of fixation parts to the optical part are provided at positions that are point symmetrical about the center point of the optical part, and the astigmatism axis is aligned with the axis connecting the two attachment parts.
An intraocular lens characterized by being shifted by 90° and set to pass through the center point of the optical part.