JPS631056B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coagulator device for forming a coagulum within the eye.

Conventional coagulator devices use an argon laser as a light source, and the light beam from the light source is attached to the patient's eye to eliminate the refractive power of the condenser lens, optical fiber, focusing optics, mirror, and cornea. Irradiation is applied to the treatment area of the patient's eye through a contact lens. On the other hand, the vicinity of the treatment area of the patient's eye is illuminated by the illumination optical system and observed by the operator via the observation optical system. Adjustment of the coagulation area of the coagulator device in this configuration is performed by the above-mentioned focusing optical system, and the coagulation optical system consisting of a light source 1, a condenser lens (collimator lens) 2, and an imaging lens 3 as shown in FIG. For example, when coagulating a very small area that is almost a point, the light source image is adjusted to be focused on the treatment area T that is deeper than the cornea C. On the other hand, when coagulating a circular portion with a radius r, for example, the imaging lens 3 is moved to a position 3' close to the patient's eye, and the light source image is formed at a position G further back than the treatment area T. As a result, a predetermined circular coagulation area is obtained at the treatment area T. Here, the solidified light flux emitted from the imaging lens 3 has a solid angle of It is desirable that the value is large. However, when the solid angle ω is increased, when the area of the treatment area is increased, that is, when the light source image is formed at a position deeper than the treatment area,
The coagulated light beam is directed toward the iris, and this eclipse amount becomes particularly large when coagulating the peripheral part of the fundus of a patient's eye or when treating an elderly patient's eye with difficulty in opening the pupil, which is inconvenient. Furthermore, if the coagulated light beam hits the iris, it is not only dangerous but also results in energy loss of the coagulated light beam.

The present invention aims to solve the above-mentioned problems of the conventional coagulator device, and its structural features include a coagulator that can move substantially along the optical axis while keeping the NA constant. A light source system having a light source and a mapping optical system are provided, and the coagulation light source is moved substantially on the optical axis to change the area where the coagulation light beam reaches the treatment site without changing the area through which the coagulation light beam passes through the cornea. That's true.

Therefore, the present invention has the following effects. 1st
In addition, by dividing the total output of the coagulation light source system by the passage area of the coagulation light beam on the cornea, the energy density of the coagulation light beam on the cornea can be calculated, and the safety of the cornea is guaranteed. Second, even when the treatment area is a large area in the peripheral part of the fundus, or when the coagulation light beam is moved by a manipulator or the like, the coagulation light beam is not cut off by the iris or the like. Therefore,
The coagulation light flux energy is effectively utilized, and there is little risk of the coagulation light flux damaging the iris or the like. Thirdly,
When the coagulation area is small, the convergence angle of the coagulation light beam can be made large, the energy density of the coagulation light beam outside the treatment area can be lowered, and safety is high. Also, even when the solidification area is small,
As in the case where the coagulation area is large, a large solid angle can be obtained, and the energy of the coagulation light source can be used effectively. Fourth, coagulation surgery is now possible even in presbyopic eyes, for which coagulation surgery was previously impossible due to a small pupil diameter, by reducing the area through which the coagulation light flux passes through the cornea. In this case, the energy density in the corneal region naturally increases, but since the energy density in the corneal region in that case can be calculated in advance as described above, coagulation treatment can be performed within a safe range.

Embodiments of the present invention will be described below with reference to the drawings. In the following example, as shown in FIG. 1, when a contact lens is used, that is, the refractive power of the cornea and crystalline lens of the patient's eye is compensated by the contact lens, and the refractive power of the anterior segment is compensated for by the contact lens. A case where the value becomes 0 will be explained. However, it is understood that the present invention also includes those designed to be used without contact lenses. In FIG. 2 showing the first embodiment, the lens 10 is thin and has a focal length f, and only the axial light beam will be considered. Minute light source 1
1 is projected by a lens 10, passes through a corneal region 12, and is imaged onto a treatment site 13. The minute light source 11 has an aperture stop 14 that moves at a constant distance on the optical axis, and the NA of the minute light source 11 is always constant. Next, as shown by the dotted line in FIG.
, the minute light source 11 and aperture diaphragm 14 move to the left by _DL to become 11' and 14', and on the other hand, the minute light source image 15 that was focused on the treatment area 13 moves to the right by _d2 . Suppose that it becomes 15'. The distance from the lens 10 to the micro light source 11 is S ₁ , the distance from the lens 10 to the imaging point 15 is S 2 , the distance from the lens 10' to the micro light source 11' is S ₂ , and from the lens 10' to the imaging point 15 Let the distance to ′ be S ₂ ′.
The distance between the corneal portion 12 and the treatment area 13 is d ₁ , and the distance between the treatment area 13 and the imaging point 15' is d ₂ . Furthermore, the light beam emitted from the minute light source 11 with an angle u ₁ with the optical axis enters the lens 10 at a height h ₁ from the optical axis, and at the imaging point 15 with an angle u ₁ ' with the optical axis. The light rays emitted from the minute light source 11' intersect and have an angle u ₂ with the optical axis, and enter the lens 10' at a height h ₂ from the optical axis. Let them intersect at u ₂ ′. All of the above light rays pass through the corneal region 12 at a height H from the optical axis. Using the above code and using S ₂ as a parameter, find D and D _L.

u ₁ = H/d ₁ h ₁ = S ₁ ′u ₁ ′ u ₁ = u ₁ ′−h ₁ /f S ₁ = h ₁ / u ₁ , and h ₂ = u ₂ S ₂ = u ₁ S ₂ u ₂ ′=u ₂ +h ₂ /f=u ₁ +h ₂ /f S ₂ ′=h ₂ /u ₂ ′ d ₂ =H/u ₂ ′−d ₁ Therefore, D=−(S ₂ ′−d ₂ −S ₁ ′)=−[S ₂ f/S ₂ +f−H/u ₁
′(1−S ₁ ′/f)(1+S ₂ /f)+d ₁ −S ₁ ′]……
(1) D _L = -S ₁ +S ₂ +D (2) Here, since the height of the minute light sources 11 and 11' is extremely small compared to the focal length of the lenses 10 and 10', , 11', the deviation between the light beam emitted from the on-axis point and the light beam emitted from the off-axis point is extremely small. By moving the minute light source 11, aperture diaphragm 14, and lens 10 according to the above equations (1) and (2), the coagulation area of the treatment area can be adjusted while keeping the diameter of the light beam passing through the corneal part 12 almost constant. Can be done.

In the second embodiment, as shown in FIGS. 3A and 3B, a minute light source 20 and a condenser lens 21 that also serves as an aperture stop are fixed, and a convex lens 23 corresponding to the lens 10 of the first embodiment and a minute light source 11 are fixed. Instead of moving, the provided concave lens 22 is moved. That is, in FIG. 3A, the light beam emitted from the minute light source 20 and the condenser lens 21 passes through the concave lens 22, the convex lens 23, and the corneal part 24, and is focused on the treatment area 25 as a minute light source image 26. Next, as shown in FIG. 3B, the concave lens 22 is moved to the right by a predetermined distance, and the convex lens 23 is moved to the left by the same distance as the lens 10 of the first embodiment and placed at 22' and 23'. Then, the minute light source image 26 moves to 26', and at this time, the mapping light flux of the minute light source at the corneal portion 24 becomes the same as that in FIG. 3A. As a result of the above, it is possible to adjust the coagulation area in the treatment region 25 while keeping the passage area of the coagulation light beam from the micro light source 20 in the corneal portion 24 constant. As a modification of the first embodiment,
It goes without saying that the present invention includes the use of the concave lens 22 as a convex lens and the convex lens 23 as a concave lens, and the use of these optical systems as a zoom optical system.

The third embodiment is a device that can adjust the passage area of the coagulation light beam in the cornea. As shown in FIG. 4, the minute light source mapping optical system consisting of the minute light source 11, aperture diaphragm 14, and lens 10 of the first embodiment, the cornea part 12 of the patient's eye, and the treatment area 13 are optically connected by a relay lens 30. Connect to. A variable diaphragm 31 is placed between the lens 10 and the relay lens 30 at a position conjugate with the corneal portion 12, and a semi-transparent mirror 32 with low reflectance is placed at an appropriate position between the lens 10 and the corneal portion 12. Set up A monitor optical system 33 is placed on the reflection optical axis of the semi-transparent mirror 32. In the above configuration, by moving the minute light source 11, the aperture diaphragm 14, and the lens 10 according to equations (1) and (2), the treatment area 13 is The coagulation area can be changed, and by adjusting the variable aperture 31, the transmission area of the coagulation light beam in the corneal portion 12 can be changed.

Next, the relationship between the size of the minute light source mentioned above and the focal length of the lens will be explained. As shown in FIG. 5, the coagulator device includes a light source 4 at a height y.
0, consists of a lens 41, and the coagulating light beam is directed to the corneal part 42.
and reaches the treatment area 43. The distance between the light source 40 and the lens 41 is S, the distance between the lens 41 and the treatment area 43 is S', and the distance between the corneal part 42 and the treatment area 43 is d. The light rays emitted from the center of the light source 40 and making angles u ₁ and u ₂ with the optical axis are incident on the lens 41 at heights h ₁ and h ₂ , and further on the corneal part 42, as shown in FIG. 5A. The light is incident on the optical axis 43 _' of the treatment area 43 _.
reach. On the other hand, the light rays emitted from the height y of the light source 40 and making angles u ₃ and u ₄ with the optical axis are incident on the lens 41 at heights h ₃ and h ₄ , as shown in FIG. 5B. Then, the light enters the corneal portion 42 at heights H ₃ and H ₄ and further reaches the treatment area 43 . In the above optical system, if = 1/f, for the axial rays 1 and 2 shown in Fig. 5A, h ₁ = Su ₁ u ₁ ′ = u ₁ + h ₁ Δh ₁ = −u ₁ ′ (S′ _-d ) H ₁ = h ₁ + _{Δh 1} Also, for _the off-axis rays _{3 and 4 shown} in FIG. ) H ₃ =h ₃ +Δh ₃ Here, the increase ΔH in the light beam passage area in the corneal portion 42 due to the light source 40 being not minute differs depending on the position of the corneal portion 42. As shown in FIG. 5C, when the distance between the corneal portion 42 and the treatment area 43 is d', ΔH is ΔH ₁₃ determined by the axial ray 1 and the off-axis ray 3. On the other hand, as shown in FIG. 5D, the distance between the corneal part 42 and the treatment area 43 is
d'', ΔH is ΔH ₂₄ determined by the on-axis ray 2 and the off-axis ray 4. If the divergence angle of the light source 40 is u, ΔH ₁₃ = | H ₁ − H ₃ | where u ₁ = u ₂ = u d = d' ΔH ₂₄ = | H ₂ − H ₄ | However, u ₂ = u ₄ = − u d = d″ From the above formula, ΔH ₁₃ = | S'-d')]-{su-(u+su)(S'-d')}|=|y-y(S'-d')/f| =|y-y/f(S'-d ′) | ΔH ₂₄ = | [y−su−{−u+(y−su)} (S′−d″)]−{−su−(−u−su)(S′ −d″)}|= |y−y(S′−d″)| =|y−y(S′−d″)/f| Therefore, ΔH=|y−y(S′−d)/f| =|y{1− (S'-d)/f}|

By the way, the coagulation area passing through the cornea is determined to be 0.3≦H≦4 based on the conditions for the coagulation light flux not to hit the iris and the conditions for keeping the density of the coagulation light flux in the cornea within a safe range. Therefore, if the allowable variation in the coagulation area passing through the cornea is α%, and if this variation is caused by the light source size 2y, then 3α/1000≦ΔH _nax ≦4α/ 100 Here, ΔH _nax = |y{1-(S'-d)/f}| is derived.

[Brief explanation of the drawing]

Fig. 1 is a principle diagram of the coagulation area adjustment of the coagulator device, Fig. 2 is an optical diagram of the first embodiment of the present invention, Fig. 3 is an optical diagram of the second embodiment, and Fig. 4 is a diagram of the third embodiment.
FIG. 5, an optical diagram of the embodiment, is an optical diagram showing the relationship between the size of the coagulation light source and the focal length. 10...Lens, 11...Minimum light source, 12...
Corneal site, 13...Treatment area, 14...Aperture diaphragm, 15...Minimum light source image, 32...Semi-transparent mirror, 33
...Monitor optical system.

Claims (1)

[Claims] 1. A light source system having a coagulation light source that can move substantially on the optical axis while keeping the NA constant, and a focal length that is sufficiently long compared to the size of the light source, and has a principal point thereof. a mapping optical system whose position is movable with respect to the treatment area, and the coagulation light beam changes the passage area of the cornea by moving the coagulation light source substantially on the optical axis and moving the principal point of the mapping optical system. A coagulator device that is characterized by changing the area that reaches the treatment area without changing it. 2. The amount of movement of the coagulation light source D _L , the amount of movement of the principal point of the mapping optical system is D, the focal length of the mapping optical system is f, the area through which the coagulation light beam passes through the cornea is a circle with radius H, and the exit of the mapping optical system is The distance from the side principal point to the treatment area is S ₁ ′,
The distance from the cornea to the treatment area is d ₁ , and the distance from the input principal point of the mapping optical system to the coagulation light source after movement is
When S ₂ , there is the relationship D _L = −S ₁ +S ₂ +D, where D=−[S ₂ f/S ₂ +f−H/u ₁ ′(1−S ₁ ′/f)(
1+S ₂ /f)+d ₁ −S ₁ ′] u ₁ ′=H/d ₁ S ₁ =fS ₁ ′/f−S ₁ ′ Coagulator device. 3. The coagulator device according to claim 1, wherein the light source system includes a fixed coagulation light source and a lens system capable of moving a virtual image of the coagulation light source on an optical axis. 4 The focal length of the mapping optical system is f, the distance from the exit side principal point of the mapping optical system to the imaging point is S', and the distance from the cornea to the imaging point is d (that is, d=d ₁
+ _d2 ), when the size of the coagulation light source is 2y and the allowable variation of the coagulation light flux passing through the cornea is α%, 3α/1000ΔH _nax 4α/100, ΔH=|y{1−(S′−d )/f}| The coagulator device according to claim 2, wherein the coagulator device has the following relationship. 5. The coagulator device according to claim 1, wherein a variable aperture is arranged at a position conjugate with the cornea.