Biomedical subjects

Xingtao Zhou

Publications and source records attributed to Xingtao Zhou.

5 recordsLinked to original sources

PubMed2006

Amniotic membrane corrects surgically induced astigmatism.

Human amniotic membrane (AM) has been widely used for the reconstruction of ocular surface. We conducted this study to investigate whether AM shows efficacy in maintaining the correction of astigmatism or not. We performed photoastigmatic refractive keratectomy (PARK) on rabbits and grafted AM on the cornea. The effect of AM on the degree of astigmatism was evaluated by topography and cycloplegic refraction. As will be shown, AM did not show any efficacy in maintaining the correction of astigmatism. On the contrary, AM not only eliminated PARK-induced astigmatism but prevented surgically induced astigmatism. We suggest that AM could be a useful tool for controlling the astigmatism induced by laser refractive surgery. Further clinical study is still left to be elucidated.

Amnion↗

PubMed2006

One-year outcomes of epi-LASIK for myopia.

PURPOSE: To evaluate the early clinical outcomes of epi-LASIK for myopia. METHODS: This study comprised 302 eyes of 162 patients. Epi-LASIK was performed with an automatically rotational epikeratome (KM-5000D). Epithelial separation was achieved mechanically without the use of alcohol. After laser ablation, the epithelial sheet was repositioned and a therapeutic contact lens was applied to the cornea immediately for 3 to 5 days. Postoperative visual acuity, symptoms, epithelial sheet, contrast sensitivity, wavefront aberration, and haze formation were evaluated 3, 6, and 12 months postoperatively. RESULTS: Of the 302 eyes, 72 eyes (42 patients) with a mean spherical equivalent refraction of -9.13 +/- 4.23 diopters (D) (range: -1.25 to -19.0 D) had > 1-year follow-up. One eye failed to make the epithelial sheet because of the narrow palpebral fissure. An integrated epithelial sheet with a diameter of 8 to 9 mm was made in 289 (95.7%) eyes, leaving a superior hinge of approximately 2 to 4 mm. In 1 eye, stromal tissue remained in the epithelial sheet. Free epithelial flaps were made in 12 (4%) eyes. Mild discomfort was reported by 150 patients (282 eyes, 93.4%). Twelve patients (20 eyes, 6.6%) reported moderate symptoms. At 1 day postoperatively, corneal epithelium was almost transparent or had mild focal edema in 288 (95.4%) eyes; moderate edema was reported in 14 (4.6%) eyes. At 1 year postoperatively, spherical equivalent refraction of 60 (83.3%) eyes was within +/- 1.0 D of attempted refraction. Grade 0.5 haze was found in 2 eyes; all other eyes had no haze. No eye lost any lines of best spectacle-corrected visual acuity (BSCVA), whereas 12 (16.7%) of 72 eyes gained one or two lines of BSCVA. Contrast sensitivity decreased 1 month postoperatively and was restored to preoperative levels in eyes with preoperative spherical equivalent refraction < -10.0 D. Higher order aberration increased significantly postoperatively. CONCLUSIONS: Epi-LASIK is a safe and efficient method to correct myopia with the advantage that it has only mild symptoms and mild haze. A larger study with longer follow-up is needed to determine its long-term clinical outcomes.

Adult↗

PubMed2006

Correlation between TGF-beta1 in tears and corneal haze following LASEK and epi-LASIK.

PURPOSE: To compare the incidence and degree of corneal haze formation following laser subepithelial keratomileusis (LASEK) and epithelial laser in situ keratomileusis (epi-LASIK), and examine its correlation with tear film transforming growth factor-beta1 (TGF-beta1) levels. METHODS: This prospective, interventional, clinical trial included 20 eyes (20 patients) randomly assigned to undergo LASEK or epi-LASIK. The level of TGF-beta1 in tear fluid was measured preoperatively and 1, 3, and 5 days postoperatively. Corneal haze was graded at 1 and 3 months after surgery, and the relationship with TGF-beta1 levels was determined. RESULTS: Mean preoperative spherical equivalent refraction was -4.50 +/- 1.44 diopters (D) (range: -1.50 to -6.00 D) for LASEK eyes and -4.90 +/- 1.26 D (range: -1.75 to -6.00 D) for epi-LASIK eyes. Although mean corneal haze scores at 1 month were significantly higher in LASEK-treated eyes than in epi-LASIK treated eyes (P=.031), these scores were similar at 3 months (P=.608). Tear fluid TGF-beta1 levels were similar in LASEK and epi-LASIK eyes before surgery (P=.458) and significantly higher in the LASEK group at 1, 3, and 5 days postoperatively (P=.015, P=.023, and P=.039, respectively). A positive correlation was noted between tear TGF-beta1 levels on the first postoperative day and the degree of corneal haze at 1 month (r=0.501, P=.016). CONCLUSIONS: Less corneal haze was noted after epi-LASIK than LASEK. A positive correlation between corneal haze and tear fluid TGF-beta1 levels on the first postoperative day suggest a possible mechanism for the observed difference.

Adult↗

PubMed2002

[The epithelial-flap abnormality of laser epithelial keratomileusis].

OBJECTIVE: To investigate the technique of epithelial-flap performance and reposition and the factors related to the complication to improve the quality of laser epithelial keratomileusis (LASEK). METHODS: Fourteen eyes (9 cases) of epithelial-flap abnormality occurring in and after the operation in 309 eyes were observed and analyzed. The factors related to the abnormal flap were listed and discussed. RESULTS: The abnormal epithelial flaps of LASEK during and after the operation were free epithelial-flap, dissolution, fragments, fold, slip, and the late epithelial-flap abnormalities including epithelial defect and sub-epithelial foreign body 48 - 72 hours postoperatively. The related factors of complication included the shallow cut of micro-trephine, improper (too small) cut ring, improper concentration of alcohol, the invasion of alcohol solution, dry center of epithelial-flap, corneal epithelial injury by irrigation, and too early removal of contact lens. CONCLUSION: The epithelial-flap of LASEK is frailer than that of LASIK. The key point in the performance of a fine epithelial-flap is to manage every procedure carefully.

Adult↗

PubMed2002

Retinal dopamine transporter in experimental myopia.

OBJECTIVE: To investigate the distribution, changes and a possible role for retinal dopamine transporter (DAT) in experimental myopia in chickens. METHODS: Two-day-old chickens were divided into four groups. Chicken eyes were fitted with lenses of -10D,-20D and translucent goggles unilaterally. Normal eyes were used as controls. After 3 wk, all chickens were given an intramuscular injection of (125)I-beta-CIT 2beta-carbomethoxy-3beta-(4-iodophenyl)tropane and sacrificed two hours post injection. Retinal pigment epithelium (RPE) and the neural retina were obtained together or RPE was dissected out from the neural retina. Radioactive DAT from each specimen was assayed by gamma-counter. RESULTS: Retinal DAT was detected in RPE specimens rather than in the neural retina in all eyes. Radioactive DAT in myopic eyes was higher, compared with control eyes. CONCLUSIONS: Retinal DAT is mainly located in the RPE and may be involved in the formation of lens induced myopia (LIM) and form deprivation myopia (FDM). These methods may provide a new approach for further studying the role of the dopamine system in experimental myopia.

Animals↗