What Is a Keratotomy?

Radial keratotomy (RK): The earliest ophthalmological literature seen in the late 19th century. From 1974 to 1979 the Soviet Union Fyodorov made a huge contribution to the development of this surgery, obtained satisfactory correction results, and developed around the world. Faster, our country began to popularize in 1978, and some hospitals are still doing this operation. The principle of this operation is to use a diamond knife to make deep radial interstitial incisions in the central and peripheral areas near the front surface of the cornea, weakening the intraocular pressure, thereby flattening the central part of the cornea, reducing its refractive power, and myopia. Reduced or completely corrected. This operation can be used as a method for treating myopia, but it is not perfect, the predictability is poor, and the complications during and after surgery affect the long-term efficacy.

1. Those who are 18 to 20 years old and whose refractive power has increased by less than 2.0D in the past two years.

2. Refractive power-2.00D ~-6.00D.

3. Occupation For those who are engaged in strenuous sports, pilots, firefighting, accounting, and computer operations, surgery should be carefully considered.

4. Exclude eye related diseases, such as dry eye, corneal disease, cataract, glaucoma, low intraocular pressure, infectious eye disease and severe intraocular disease.

5. Psychological abnormalities should be performed with caution. ^[1]

1. Progressive myopia.

2. Keratoconus.

3. suffer from other eye diseases, such as glaucoma, cataract, dry eye and so on. ^[1]

Surface anesthesia, subconjunctival anesthesia, some patients can be anesthetized after the ball. ^[1]

1. Small pupil and mydriatic computer and retinoscopy, eye movement examination, intraocular pressure measurement, external eye examination, slit lamp microscope examination and fundus examination, etc.

2. Corneal curvature meter and computer-aided corneal topography.

3. Corneal thickness measurement. The results of ultrasonic corneal thickness measurement are more accurate.

4. A-axis front and rear axial length measurement.

5. Scleral hardness, anterior chamber depth, corneal endothelial cells and corneal tactile examination. ^[1]

1. 1% pilocarpine shrinks pupils 1 hour before surgery.

2. For topical anesthesia, apply 0.5% dicaine or 0.4% topical anesthesia to the pupil, once every 5 minutes for a total of 3 times.

3. Eyelid opener.

4. The patient looks at the coaxial light source of the surgical microscope to determine the center position of the corneal optic axis.

5. With the visual axis as the center, use the visual field positioning marker to determine the central visual field.

6. The incision marker determines the number and position of incisions.

7. Fix the eyeball with a scleral fixator. A diamond knife cuts the corneal thickness vertically to 90% to 95% along the incision mark.

Cut the anterior cornea, the surface should not be too dry or too wet to reduce resistance and avoid epithelial wear. The incision order is 90 ° ~ 270 °; 0 ° ~ 180 ° are cut symmetrically. The thinnest part of corneal ultrasound thickness measurement can be arranged at the last incision, so as not to cut through early and affect the operation.

8. After all incisions are completed, rinse the incision with a balanced salt solution to remove epithelial debris.

Check the depth of each incision to see if there are small perforations.

9. After the operation, 20,000 units of gentamicin and 2.5 mg of dexamethasone were injected under the conjunctiva. In order to reduce pain during or after injection, 2% lidocaine 0.5ml can be added to the solution. ^[1]

1. Eyeballs should be well fixed.

2. The cutting knife should be stable when cutting, and the cut should be straight.

3. The diamond knife and foot plate should be kept perpendicular to the corneal surface to ensure the same incision depth.

4. Once cut through, the knife should be stopped immediately, and the small perforation can be closed by itself. If there is too much aqueous humor, the anterior chamber becomes shallow, and the intraocular pressure is low, the operation should be stopped and the incision closed. Depending on the recovery situation, another operation or excimer laser photorefractive keratectomy was performed. ^[1]

1. Change the dressing daily after surgery, check the eye condition and vision, and check the refractive status by optometry. For undercorrection, apply appropriate pressure bandages and point the eye with corticosteroids. Mild overcorrection does not require special treatment. Can be taken orally with acetazolamide and pilocarpine eye drops or timoloxan eye drops.

2. For those with obvious pain, topical application of short-acting mydriatic can reduce ciliary muscle spasm, and oral sedative pain can be taken at the same time.

3. Regular review.

4. Avoid more violent activities, such as boxing and football. ^[1]