Soft intraocular lens implantation

In 1982, Kelman proposed the ten principles of an ideal intraocular lens: 1 Regardless of whether the eyeball is at rest or deformed, the intraocular lens cannot move at all in the eye. 2 Under the same circumstances, the lens cannot compress the tissue in the eye. 3 When the eyeball is deformed, there is no change in the contact area between the lens and the eye. 4 no physical and irritating. 5 will not increase the chance of reoperation due to dislocation or size discomfort. 6 Not only for experts, but also for beginners. 7 No part of the intraocular lens will adhere to any tissue in the eye. 8 The intraocular lens must be suitable for any type of surgery, including intracapsular, extracapsular and phacoemulsification cataract extraction, and secondary intraocular lens implantation. 9 late complications should be expected and can be treated. 10 lenses of the same size should be suitable for all eyes. Hollady (1986) also puts some requirements on the lens configuration from the optical and physics perspectives: 1 good resolution, measured in air should be greater than 100 lp / mm. 2 no spherical aberration. 3 When the lens is eccentric, the resulting refractive change and spherical aberration should be small. 4 When the lens is tilted, it should be small to cause changes in refractive and spherical aberration. 5 spectral transmission characteristics should be consistent with the natural lens. 6 should have a large enough optical diameter so that edge inging does not occur when eccentricity occurs. 7 should be an inert material and will not biodegrade due to chemical factors such as ultraviolet radiation. 8 The surface is smooth with no rough or sharp edges. 9 small specific gravity to reduce the inertia and weight of the movement. 10 thickness should be as thin as possible. It is clear that the ideal intraocular lens does not exist. But what is certain is that the quality of the IOL has reached a considerable level after repeated clinical practice and unremitting efforts of design and production personnel. When selecting the intraocular lens, the standard of the ideal intraocular lens should be referred to, combined with other influencing factors, to make a comprehensive judgment. Treatment of diseases: crystal ectopic and dislocation of the crystal dislocation Longitudinal implantation technique (1) The lens is taken out of the package with a clean, dry, toothless thread. Place the intraocular lens in half by placing it in a special folding placket. The folded intraocular lens is then clamped with the implant. (2) Insert the folded intraocular lens into the anterior chamber by inserting the folded edge to the left and paralleling the tunnel incision. Adjust the angle so that the lower jaw enters the pocket. (3) When it is confirmed that the lower jaw has entered the capsular bag, gently rotate the implant to the right, turn the folding edge upward, and slowly release the implant sputum; when the lens is fully deployed, slowly withdraw from the implant sputum. (4) The upper jaw is implanted with the same method of rigid intraocular lens implantation. 2. The lateral implantation technique is different from the longitudinal implantation technique in that the lateral implantation technique is a method in which the intraocular lens is laterally folded, that is, the iliac crest is folded and then reimplanted. The advantage of this method is that when the intraocular lens is delivered into the pouch to release the implant, the intraocular lens will be deployed directly into the pouch without the need to dispose of the palate. The specific operation method is as follows. (1) The intraocular lens is laterally folded in half by implantation. (2) The slit is placed in a manner parallel to the outer slit of the tunnel so that the two jaws are compressed against the side edge of the folded opening. The lens is folded and brought into contact with the incision, and the inner/outer rotation is 90°, so that the longitudinal axis of the lens is perpendicular to the incision and then inserted into the incision. (3) When the intraocular lens optic portion enters the capsular bag, the folded ridge is rotated 90° to the right to be vertically folded. Gently relax the folding plaque, the intraocular lens will expand with its own elasticity, and the two sacs will also enter the sac and extend to the equator. complication 1. Post-elastic membrane detachment occurs in cases where the incision is too small, the incision is in front, and the tunnel is too long. The edge of the lens optic can be pushed directly, causing the posterior elastic membrane to detach. If this happens, the adhesive should be injected onto the lens to change the state of the upturn, so that the leading edge slides down. 2. Corneal endothelium injury If the anterior chamber is too shallow to implant the lens, especially in the anterior chamber lacking viscoelastic protection, the lower edge of the lens can scrape the corneal endothelium, causing serious damage. Injecting enough viscoelastic to create enough space in the anterior chamber to avoid this. 3. Iris injury When there is a shallow anterior chamber, the position of the incision is back, the lower jaw of the lens can push the upper iris, the lighter depigmentation, the severe one can cause the iris root to break and even the anterior chamber hemorrhage. A simple treatment method is to inject a viscoelastic agent into the surface of the iris below the incision before implanting the intraocular lens to indent the iris to form a wide channel, and then implant the intraocular lens as required. 4. Posterior capsule rupture When the maximum diameter of the intraocular lens of the intraocular lens passes over the incision, it tends to turn down in vain. At this time, if you do not pay attention to controlling the angle of the downtilt and grasp the pushing force, the lower jaw can break the posterior capsule and have serious consequences. . Preventive measures include mastering the correct angle and intensity of advancement and avoiding the occurrence of missing. When the maximum diameter of the lens passes over the incision, it is best to hold the posterior iliac crest and gently push the lens to slowly slide into the capsular bag by the elastic force transmitted by the sputum, so-called "soft implantation"; The "hard implant" into the pouch is prone to damage to the posterior capsule. 5. The suspensory ligament is broken. When the lens is lack of elasticity and the operation is not standardized, it is easy to break the suspensory ligament in addition to the damaged capsule. This is also likely to occur when a large-diameter intraocular lens is implanted with a small capsulorhexis. 6. The lens is broken. When the incision is too small, or irregular, and the implanted intraocular lens is too thick, if it is to be implanted rigidly, it will often break, especially when implanting the folded intraocular lens. . The precautionary approach is to prefer to slightly enlarge the incision rather than to maintain the concept of absolute small incision. In addition, when the intraocular lens is implanted, the lower jaw is first inserted into the incision and then implanted into the optical portion to reduce the "crowding" phenomenon caused by the overlap of the pupil and the optical portion. 7. Intraocular lens reversal Whether it is a hard lens or a foldable lens, there is a possibility of reversing it, especially folding the lens, which is more likely to occur. Once the intraocular lens is found to be reversed, it should be reset. After injecting the viscoelastic agent, the optical portion of one side is pressed down by the auxiliary device to cause the warp plate to be reversed. Care should be taken to protect the corneal endothelium, iris and posterior capsule during operation.