Double Excimer Laser in situ keratomileusis-cutting, after
correction of high myopia after scleral reinforcement efficacy
Author: Bacillus, Fang Xue-Jun, Mo-Jun Bai, Feng
Yuning, PANG Dong-Bo
【Abstract】 Objective: To evaluate excimer laser in situ
keratomileusis-sided, after correction of high myopia after scleral reinforcement effectiveness. Methods: 18 cases (36 eyes) with posterior scleral reinforcement surgery in patients with high myopia, refractive stability than 1a, line both
sides excimer laser in situ keratomileusis, to observe the postoperative visual acuity, refraction changes. Results: 17 patients with uncorrected visual acuity (uncorrected visual acuity, UCVA) meet or exceed the preoperative best corrected
visual acuity (best corrected visual acuity, BCVA), 1 postoperative uncorrected visual acuity compared with preoperative best corrected visual acuity decreased by 1 line. Diopter of myopia from -11.58 ? 1.57 D preoperatively to
reduce postoperative 3mo pm -0.51 ? 0.96 D. Conclusion: The
excimer laser in situ keratomileusis double-cutting operation,
after correction of high myopia after scleral reinforcement predictability, effectiveness and stability.
Key words excimer laser in situ keratomileusis
Excimer laser in situ keratomileusis (LASIK) is widely used in clinical practice varying degrees of myopia, and have achieved a good therapeutic effect. However, some patients with partial thin central corneal thickness and / or high
myopia and high myopia and its poor stability factor , so we take first posterior scleral reinforcement surgery, refractive stability of 1a-line for more than two-sided type
(both side) LASIK corrective surgery (BSL). Now 18 cases of 36 patients reported clinical efficacy is as follows.
An object and method
1.1 Object 2004-05/2005-02 excimer center in our hospital
and seek treatment for patients with high myopia, in my hospital or outside the hospital has been in posterior scleral reinforcement 1a above, refractive stability and 1a, a total of 18 cases (36), in which men 7 (14), female 11 (22), age 19 to 42 (mean 25.4 ? 5.3) years old, line BSL surgery. In
patients with preoperative routine for distance and near vision, computer optometry, optometry dilation, comprehensive Refractometer optometry, corneal refractive power, intraocular pressure, slit-lamp, corneal thickness, axial length, indirect ophthalmoscopy fundus check, corneal topography examination. Best corrected visual acuity (BCVA) ? 0.6. Preoperative
refraction was -8.25 ~ -14.25 (mean -11.58 ? 1.57) D:
astigmatism of -0.50 ~ -3.50 (mean -1.58 ? 0.64) D, central
corneal thickness of 490 ~ 559 (mean 511.59 ? 15.16) μm.
Axial length 25.47 ~ 30.25 (average 27.96 ? 0.92) mm.
1.2 Methods of preoperative refraction and corneal thickness according to the patients the amount of cutting to two-step distribution, in order to protect the corneal stromal bed thickness greater than 250μm, corneal stromal bed greater
than the optical zone cutting 5mm, trimming more than 7.5mm for the first design principle. First, for the treatment of central corneal thickness to allow volume (including astigmatism), that "central corneal thickness - flap thickness
(130μm)-250μm" remaining after cutting thickness can provide
the amount of stroma in situ cutting; followed by the amount of the remaining treatment (purely spherical) and the design on the back flap in the corneal stroma cutting. Conventional LASIK surgery preoperative preparation. Topical anesthesia,
open eyelid. In the cornea with gentian violet marker leather line optical center anchor, the use of Japanese Nidek company MK2 000 flat push-type automatic corneal lamellar knife, 130μ
m Cutter, 8.5 suction ring, doing the pedicle at 12:00 the
vertical direction of corneal flap. Flip flap attached to the leather flap on the self-supporting device on the center-
marked point scanning center, application Japan, Nidek company EC5 000 excimer laser system in order to double-cross
fractured band of light to determine the level of the face of corneal flap of corneal flap substrate surface a first step, laser cutting, the pupil optical center targeting centers to the second step of matrix-bed laser cutting, washing reset
under the corneal flap with conventional LASIK surgery,
postoperative treatment with conventional LASIK surgery.
2.1 In general began to appear after 1h tears and mild foreign body sensation, are in the 8 ~ 10h disappear, postoperative corneal flap 1d slit-lamp examination, see
clear, and flap edge of epithelial cells have been healed, the corneal flap a good reset.
2.2 Preoperative UCVA mean visual acuity 0.13 ? 0.03,
after 1,15 d; 1,3 mo mean, respectively: 0.71 ? 0.20,0.88 ?
0.17,0.95 ? 0.15,0.97 ? 0.13. 34 Yan met or exceeded the
preoperative best corrected vision, 2 visual acuity compared with preoperative best corrected visual acuity decreased by 1 line, mainly due to undercorrection actions, has yet to decreased vision 2 monk.
2.3 diopter diopter of myopia from -11.58 ? 1.57D
preoperatively after 3mo when reduced to -0.51 ? 0.96D. 15d
after surgery when the refraction was 0.33 ? 0.65D, 1mo when
the refraction was -0.10 ? 0.77D, 3mo when the refraction was -0.51 ? 0.96D, astigmatism 15d after surgery for -0.21 ?
0.99D, 1mo when astigmatism of -0.53 ? 0.77D, 3mo, when
astigmatism of -0.67 ? 0.64D. Reposted elsewhere in the paper for free download http://
A high degree of myopia is a form of axial length growth of choroid and retina of eye injury organizations visual disturbance caused by eye disease. Its cause of blindness was not due to a high degree of refraction, but the fundus lesions. Therefore, how to prevent the growth of axial length in order to prevent and mitigate high myopia due to axial
extension of the fundus caused by disease, to protect the patient's vision, the key to the treatment of high myopia.
Posterior scleral reinforcement through the application of reinforcement material close to the posterior pole of the
sclera thinner walls, so that the area sclera wall thickening, an increase of sclera toughness, changing the mechanical characteristics , to prevent or mitigate the conduct of the sclera organization expansion, thinning and the resulting traction on the posterior pole retinal traction caused by progressive damage. The formation of thicker posterior scleral reinforcement surgery "new sclera," an increase in angiogenesis and improve the choroid, retinal blood circulation, improve the nutritional status of the posterior
pole to improve the patient's visual function . So the first consideration in patients with high myopia is to protect the visual function, and then consider the refraction correction. On the other hand, a high degree of myopia is a special kind of people, their own refraction in progress. In this group of 18 selected cases of high myopia is to implement a stable refraction after posterior scleral reinforcement 1a above, re-refractive surgery, the basic control of the excimer preoperative refractive instability.
LASIK treatment, a high degree of myopia of the efficacy and safety has been confirmed that the surgery because of corneal epithelium and the former retains the integrity of the elastic layer, more in line with physiological anatomy of the
cornea. With a painless, quick recovery and postoperative visual acuity, refractive regression less and so on. However, some bias in patients with thin corneas and / or the refraction is too high, if the design or improper operation caused by over-reserved for laser cutting matrix thin side, there is the risk of postoperative secondary keratoconus and therefore not suitable for surgery. In addition to ultra-high
myopia (> 9.00D) correction, due to postoperative refractive regression, diopter poor stability, so that ophthalmologists on whether to impose surgery have different opinions. Screening in this group of patients with high myopia is a refractive surgery after the implementation of the number of scleral reinforcement stable 1a, OK BSL surgical correction of
high myopia, postoperative general, no significant difference with the traditional LASIK, 94% of the uncorrected visual acuity reached or exceeded the preoperative best corrected vision, the same with the response to light, the advantages of
rapid recovery. That BSL after treatment with high myopia after scleral reinforcement predictability, effectiveness and
LASIK surgery, corneal flap created with corneal epithelium, Bowman layer and a certain thickness of the corneal stroma, BSL surgery is the laser-cutting matrix of
cutting the amount of bed-sharing can not be completed in the corneal flap back of the substrate, Li Zhao Xia et al  studies suggest that the cornea valve for the maintenance of normal cornea has no direct role in intensity. Retained the matrix bed reserved for cutting the thickness of the post within the safety area, eliminating the risk of postoperative major keratoconus. There are reported postoperative LASIK corneal expansion, the majority of people think that to
maintain normal corneal integrity and bio-mechanical strength
to prevent expansion of the cornea, the remaining corneal stromal bed kept for at least 250μm. Chenyue Guo et al 
reported 1 case of residual corneal stroma bed after LASIK
thickness of 286μm is happening keratoconus [6,7]. Note the remaining corneal stromal bed after LASIK should seek to maximize the thickness of the thickness.
Preoperative corneal accurate pupil center position and laser in-situ substrate cutting pupil position in line to
ensure the corneal flap-cutting and matrix on the back of the cutting bed cutting Precise center right together to ensure that post-operative visual acuity, an increase of surgical treatment can diopter range, expanded the indications .
Double-sided cutting corneal stroma, cutting the main part of the first substrate layer, as the former is more than the number of stroma nuclei after the stroma , postoperative stability. While avoiding the cutting of small optical zone produced by refractive regression, glare and other complications.
This group of cases, 8 cases of postoperative uncorrected visual acuity compared with preoperative best corrected visual acuity was improved, it is because the corneal plane refractive correction can be carried out to
eliminate a certain distance away from the cornea with a
framework for object-image to narrow the role of glasses, so that macular things like the increase to restore the proportion of retinal imaging. The other one cases of postoperative uncorrected visual acuity compared with preoperative best corrected visual acuity decreased by 1 line,
mainly due to undercorrection Suo Zhi.
Excimer laser treatment of high myopia, postoperative refractive stability of the confusion of an ophthalmologist the question of whether surgery is also controversial, as this
group of patients have a strong desire to Zhai mirror, we have a stable line of posterior scleral reinforcement surgery 1a of the double row of high myopia excimer laser in situ keratomileusis, and its stability, safety, efficacy has been confirmed. But its long-term effects need to be further
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