The accommodative function before and after laser in situ keratomileusis (LASIK) was observed, and the effect of LASIk on accommodation was investigated. In a prospective clinical trial, 48 myopic patients (96 eyes) subject to bilateral LASIK in Refractive Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology (China) from March 2006 to June 2006 were selected and studied. Refractions, accommodative range, amplitude of accommodative response and high frequency component (HFC) of accommodative microfluctuations were measured with NEDIK-730A before and one week and 30 days after operation. Dominant and non-dominant eyes were determined by hole-in-card method. It was found that all of the operative eyes showed an uncorrected visual acuity of 0.8 or better one week postoperatively, and 1.0 or better 30 days postoperatively. Compared with those preoperatively, accommodative range and HFC had no significant difference at first week and 30th day after operation in both dominant eyes and non-dominant eyes (P>0.05), but there was a significant difference in the amplitude of accommodative response/accommodative stimulus ratio (A/S) after operation (P<0.01), and no significant difference was found in accommodation between one week and 30 days postoperation. No ocular dominance's change was noted. There was no significant difference in accommodative function between dominant eyes and non-dominant eyes. It was suggested that LASIK produced no significant effect on accommodation.
Accommodation, Ocular/*physiology ; Keratomileusis, Laser In Situ/*adverse effects ; Myopia/*physiopathology ; Myopia/*surgery ; Postoperative Period ; Prospective Studies ; Young Adult

PURPOSE: To compare forward shift of posterior corneal surface and higher-order aberration (HOA) changes after LASIK, LASEK, and wavefront-guided LASEK surgery in moderate myopia METHODS: One hundred eighty four eyes undergoing LASIK, LASEK and wavefront-guided LASEK with VISX STAR S4 were included in this study. The posterior corneal elevation was measured with Orbscan before, 2 and 4 months after surgery. Changes of the elevation were assessed using the difference map generated from preoperative and postoperative elevation maps. The values of higher-order aberrations were evaluated preoperatively and 2 months postoperatively with Wavefront aberrometer. RESULTS: The posterior corneal surface displayed forward shift of 27.2+/-11.45 micrometer, 24.3+/-9.76 micrometer in LASIK group, 23.4+/-10.5 micrometer, 23.6+/-10.55 micrometer in LASEK group, 24.0+/-14.95 micrometer, 28.4+/-14.72 micrometer in wavefront-guided LASEK group at 2 months and 4 months, respectively. There were no statistically significant differences among those three groups, and between 2 and 4 months. The root mean score (RMS) of HOA was increased after LASIK and LASEK (p=0.000, p=0.000, respectively). The mean change of HOA-RMS was significantly smaller in wavefront-guided LASEK than LASIK or LASEK (p=0.000, p=0.000, respectively, Bonferroni-corrected). CONCLUSIONS: The changes of posterior corneal surface forward shift showed no difference among LASIK, LASEK and wavefront-guided LASEK in moderate myopia. HOAs were significantly increased after LASIK and LASEK. The changes of HOAs were significant smaller in wavefront-guided LASEK than LASIK or LASEK.
Adult ; *Corneal Topography ; Humans ; Myopia/diagnosis/*physiopathology/*surgery ; Postoperative Period ; *Refractive Surgical Procedures ; Severity of Illness Index

OBJECTIVETo evaluate the static and dynamic contrast sensitivity changes in myopic patients before and after laser in situ keratomileusis (LASIK).

METHODSSeventy-three eyes in 37 patients with myopia (with or without astigmatism) who received LASIK were tested for static and dynamic contrast sensitivities using the METRO VISION MON ELEC I system at 0.7, 1.4, 2.7, 5.5, 11, and 22 cpd and cps prior to LASIK, and at one-, three-, and six-month intervals after LASIK.

RESULTSAll eyes gained naked visual acuity of more than 0.5 after LASIK. The contrast sensitivity was depressed at all frequencies 1 month after LASIK, as compared to one week prior to LASIK. The depression at 2.7, 5.5, 11 (P < 0.01) and 22 cpd (P < 0.05) was statistically significant for static contrast sensitivity, and also at 5.5 (P < 0.01) and 11 cps (P < 0.05) for dynamic contrast sensitivity. Myopic eyes between 6.25 D and 14.0 D, and astigmatic eyes 2 DC and more, suffered more static and dynamic contrast sensitivity depression than the myopic eyes between 1.25 D and 6.00 D and astigmatic eyes less than 2 DC. Contrast sensitivities were improved and exceeded preoperative levels 3 months after LASIK, and improved even more 6 months after LASIK. All sequences were statistically significant for static contrast sensitivity (P < 0.01), while only 2.7, 5.5, and 11 cps were statistically significant for dynamic contrast sensitivity (P < 0.01). The astigmatic eyes 2 DC and more showed less improvement, even below the preoperative level at 1.4 cps of dynamic contrast sensitivity.

CONCLUSIONSWhile temporary depression of contrast sensitivity for myopic eyes after LASIK was seen, contrast sensitivity soon returned to exceed preoperative levels at 3 months after LASIK, while improving even more 6 months after LASIK.

Adolescent ; Adult ; Astigmatism ; surgery ; Contrast Sensitivity ; Cornea ; surgery ; Female ; Humans ; Keratomileusis, Laser In Situ ; Male ; Myopia ; physiopathology ; surgery ; Visual Acuity

This study sought to characterize the biomechanical properties of rabbit sclera after posterior sclera reinforcement operation (PSR), which may provide valuable information for PSR in clinical setting. Uniaxial tension and ball-pressing methods were used. Different areas of the sclera samples from PSR were examined in pretest, relaxation and creep experiments respectively by using Instron5544 mechanical machine. The experimental results showed: When the implanted area of sclera samples was compared with that of other groups, the unit width stiffness coefficient increased remarkably at the linear stage, and the anti-deformation capacity was higher at the relaxation stage. However, the creep rate showed a significant decrease at the creep stage. That is to say, PSR could enhance the anti-deformation capacity of the weakened and thinned sections, reduce the sclera creep rate in the posterior sclera, and thus prevent the development of progressive myopia.
Animals ; Biomechanical Phenomena ; Female ; Implants, Experimental ; Male ; Myopia ; physiopathology ; surgery ; Rabbits ; Sclera ; physiology ; surgery ; Scleroplasty ; methods ; Stress, Mechanical

PURPOSE: To compare changes of anterior corneal aberration (Pentacam(R)) and ocular aberration (aberrometer, LADARWave(R)) after laser refractive surgery. METHODS: Sixty-six eyes underwent laser refractive surgery and were retrospectively reviewed. Anterior corneal aberration and ocular aberration were measured by Pentacam(R) and an aberrometer (LADARWave(R)) respectively. Changes of root mean square (RMS) values of coma, spherical aberration, and total high order aberration (HOA) were evaluated before, 1 month, and 3 months after surgery RESULTS: Ocular aberrations displayed low preoperative values, but after laser refractive surgery, anterior corneal aberration and ocular aberration increased equally. There were no statistically significant differences of internal optics aberration values (ocular aberration minus anterior corneal aberration) in coma, spherical aberration, and total HOA. Anterior corneal aberration and ocular aberration showed statistically significant correlations at 1 and 3 months after surgery. CONCLUSIONS: Internal optics aberration compensated the anterior corneal aberration effectively before surgery, but the increase of anterior corneal aberration after laser refractive surgery exceeded the compensation of internal optics. As a result, anterior corneal aberration and ocular aberration increased equally. The correlation between anterior corneal aberration and ocular aberration after surgery was statistically significant due to the increased proportion of anterior corneal aberration in ocular aberration.
Adult ; Cornea/*physiopathology ; Corneal Topography ; Humans ; Lasers, Excimer/*therapeutic use ; Myopia/surgery ; Photography ; Refraction, Ocular/*physiology ; Refractive Errors/*physiopathology ; *Refractive Surgical Procedures ; Retrospective Studies

To investigate the chronological change of refraction in premature infants after cryotherapy for retinopathy of prematurity (ROP), cycloplegic refractions had been performed at 6 months and 3 years after term in premature infants who underwent cryotherapy for ROP. The changes of refractions between the two study ages were evaluated not only in the total cryo-treated eyes, but also in the subdivided groups according to the posterior pole appearances. In the total 61 eyes of 32 premature infants, mean spherical equivalents were -4.05D vs. -5.94D (6 months vs. 3 years) (p = 0.0001). In the normal posterior pole group (48 eyes), mean spherical equivalents were -3.45D vs. -5.68D (6 months vs. 3 years) (p = 0.0000), and in the abnormal posterior pole group (13 eyes), -6.28D vs. -6.86D (6 months vs. 3 years) (p = 0.6496). These results mean that there is a myopic progressive change between 6 months and 3 years after term in the cryo-treated eyes for acute ROP and it is more evident in the eyes with normal posterior pole.
Acute Disease ; Child, Preschool ; Cryosurgery/*adverse effects ; Follow-Up Studies ; Gestational Age ; Humans ; Infant ; Infant, Newborn ; *Infant, Premature ; Myopia/*etiology/physiopathology ; *Refraction, Ocular ; Retinopathy of Prematurity/physiopathology/*surgery

We report the outcome of conventional epipolis laser in situ keratomileusis (Epi-LASIK, flap-on) and lamellar epithelial debridement (LED; Epi-LASIK, flap-off) in myopic patients with dermatologic keloids. Three patients, who were all noted to be susceptible to keloid scarring, received conventional Epi-LASIK in their right eyes and LED in their left eyes. The patients were followed-up for 6 to 21 months after their surgeries, and the outcomes were then evaluated. In case 1, the preoperative spherical equivalent (SE) was -6.5 diopters (D) in the right eye (OD) and -6.25 D in the left eye (OS). At 21 months postoperatively, the uncorrected visual acuity (UCVA) was 20 / 12.5 in both eyes. In case 2, the preoperative SE was -5.25 (OD) / -6.00 (OS). After six months, the postoperative UCVA was 20 / 12.5 in both eyes. In case 3, the preoperative SE was -4.5 (OD) / -2.0 (OS). The UCVA at the six-month follow-up was 20 / 12.5 in both eyes. No adverse events, including corneal haze, occurred in any of the patients. All three of our patients reported excellent visual outcomes following both conventional Epi-LASIK and LED, despite their histories of keloid formation. The present cases suggest that both Epi-LASIK and LED may be safe and effective techniques for myopic patients with dermatologic keloids.
Adult ; *Debridement ; Eyeglasses ; Female ; Follow-Up Studies ; Humans ; Keloid/complications/physiopathology/*surgery ; Keratomileusis, Laser In Situ/*methods ; Myopia/complications/physiopathology/*surgery ; Postoperative Period ; Skin Diseases/complications/physiopathology/*surgery ; Treatment Outcome ; Visual Acuity

This study was performed to investigate the corneal epithelial healing time and rate according to the method for promoting the reepithelization after myopic epikeratoplasty. A prospective study was conducted on 30 myopic epikeratoplasties which were divided into 3 groups according to the method for promoting the epithelial healing. The groups consisted of 10 eyes with pressure patches, 10 eyes with Acuvue(R) disposable contact lens (CL) and 10 eyes with SeeQuence(R) disposable CL. The cornea epithelial healing time were 3.4, 3.5 and 3.4 postoperative days for the pressure patch, Acuvue(R) CL and SeeQuence(R) CL groups, respectively. The corneal epithelial healing rates during postoperative 1, 2, and 3 days were 0.33, 0.78, and 0.44 mm2/hour for the pressure patch group; 0.24, 0.92 and 0.37 mm2/hour for the Acuvue(R) CL group; and 0.30, 0.79 and 0.38 mm2/hour for the SeeQuence(R) CL group. These results suggest that a disposable contact lens may not hinder epithelial healing compared with a pressure patch.
Adult ; Bandages ; Contact Lenses ; Cornea/*physiology/surgery ; *Corneal Transplantation ; Epithelium/physiology ; Female ; Humans ; Male ; Middle Aged ; Myopia/*physiopathology/surgery ; Prospective Studies ; Time Factors ; Wound Healing/*physiology

PURPOSE: To evaluate factors responsible for the variability between intended and achieved corneal-flap thickness during femtosecond laser-assisted laser in situ keratomileusis (LASIK). METHODS: A prospective, nonrandomized, case study was performed on 35 eyes of 18 consecutive patients who underwent LASIK surgery using the 60 kHz femtosecond laser microkeratome. Eyes were assigned to three different thickness groups, with 110-, 120-, or 130-microm cut depths. Anterior segment optical coherence tomography was used to assess the morphology of 35 LASIK flaps at postoperative one week postoperatively. The flap thickness was assessed at seven measuring points across each flap. Patient age, preoperative spherical equivalent, manual keratometry, preoperative central pachymetry, and regional variability of the cornea were evaluated to determine where they influenced the achieved corneal flap thickness. RESULTS: Cuttings of all flaps were easily performed without any intraoperative complications. Flap-thickness measurements had a mean of 115.21 +/- 4.98 microm (intended thickness, 110 microm), 121.90 +/- 5.79 microm (intended, 120 microm), and 134.38 +/- 5.04 microm (intended, 130 microm), respectively. There was no significant difference between the 110-microm and 120-microm groups when compared with the 130-microm group (one-way analysis of variance test, p > 0.05). Patients' age, preoperative spherical equivalent, manual keratometry, and preoperative central pachymetry did not affect the achieved flap thickness (Pearson correlations test, p > 0.05). The reproducibility of flap thickness in the central 1.5-mm radius area was more accurate than that in the peripheral 3.0 to 4.0-mm radius area (paired samples t-test, p < 0.05). CONCLUSIONS: Femtosecond laser-assisted LASIK is likely to reproduce a reliable thickness of the corneal flap, which is independent of corneal shape factors or refractive status. Future studies should focus on variations in corneal biomechanical factors, which may also play an important role in determining flap thickness.
Adult ; Cornea/*surgery ; Female ; Humans ; *Keratomileusis, Laser In Situ ; *Lasers, Excimer ; Male ; Myopia/physiopathology/surgery ; Postoperative Period ; Prospective Studies ; Refraction, Ocular ; *Surgical Flaps ; Visual Acuity ; Young Adult

PURPOSE: To compare the accuracy of central true net corneal power (cTNP) and mean true net corneal power (mTNP) of the Pentacam system to give a keratometry (K) reading for calculating IOL (intraocular lens) power in eyes following refractive surgery. METHODS: Refraction, an automated K-reading (Km), cTNP and mTNP were measured for 15 eyes that required cataract surgery and had previously undergone refractive surgery. The difference between postoperative manifest refraction values and target refraction values calculated with the SRK/T formula using cTNP were compared with the one using mTNP. RESULTS: The mean deviation from the desired post-cataract refractive outcome was 0.60 diopter (D) +/-0.47 (standard deviation) using cTNP; 0.75+/-0.54 using mTNP (p=0.386). The actual refraction was within +/-0.50D of the intended refraction for 60% (cTNP) and 33.3% (mTNP) of eyes, and within +/-1.00D for 93% (cTNP) and 66.7% (mTNP) of eyes. CONCLUSIONS: Although not statistically significant, the cTNP showed better accuracy than mTNP to give a keratometry (K) reading for post-refractive surgery eyes requiring cataract surgery.
Adult ; Cornea/*pathology/physiopathology/surgery ; Corneal Topography/*methods ; Female ; Humans ; *Lenses, Intraocular ; Male ; Middle Aged ; Myopia/*surgery ; Prosthesis Design ; *Refraction, Ocular ; *Refractive Surgical Procedures