17,977 research outputs found
Zai guo leng ba, nie, lin ya wen ye tai hu rong jian xi wai duan cheng you xu jie gou de zhuan bian
No full textLo, Yin Fung = 在過冷鈀, 鎳, 磷亞穩液態互溶間隙外短程有序結構的轉變 / 盧彥鋒.Thesis M.Phil. Chinese University of Hong Kong 2015.Includes bibliographical references.Abstracts also in Chinese.Title from PDF title page (viewed on 03, January, 2017).Lo, Yin Fung = Zai guo leng ba, nie, lin ya wen ye tai hu rong jian xi wai duan cheng you xu jie gou de zhuan bian / Lu Yanfeng
Analysis of Corneal Topography after Excimer Laser Photorefractive Keratectomy
No full textExcimer laser photorefractive keratectomy (PRK) is an effective treatment for myopia. We investigated the magnitude of optical zone decentration and qualitative patterns of corneal topography after this treatment. We performed computer-assisted videokeratography on 44 myopic eyes (29 patients) that had undergone PRK before and 1, 6, and 12 months after the procedure. Associations of clinical outcomes with decentration and topographic patterns were assessed. The normalized scale of the topography 1 month postoperatively showed a mean decentration of 0.33 +/- 0.23 mm ( range 0-0.9). Thirty-four eyes had decentration of less than 0.50 mm; 10 had an ablation zone decentered from 0.5 to 0.9 mm. Analysis of geometric mean visual acuities between eyes with less than 0.5 mm decentration and those with 0.5 to 0.9 mm decentration demonstrated minimal differences. No eye was decentered more than 1 mm. Four main ablation patterns were noted on subtraction analysis: homogeneous, semicircular, keyhole, and central island. Over time, the number of eyes with a homogeneous pattern increased . Eyes with a homogeneous ablation pattern had significantly better uncorrected visual acuity than those with other patterns. The mean visual acuity was 20/29.1 in the homogeneous group and 20/38.5 in the pooled irregular group 1 month postoperatively (p < 0.05). There was no significant difference among the four ablation patterns at 6 or 12 months after PRK. Topographic patterns were not significantly associated with best-corrected vision
超高頻生物顯微鏡偵測結膜下眼窩靜脈瘤
No full text眼結膜下靜脈瘤在臨床上極為罕見。本文報告一位24歲女性患有左眼結膜下眼窩靜脈瘤，電腦斷層掃瞄並未發現任何病灶，但是以超高頻生物顯微鏡發現在結膜下有一中等反射度程度的橢圓形病灶，且病灶與鞏膜並不相連，術前診斷疑似結膜下眼窩靜脈瘤。病患因美觀及診斷因素接受手術，病理報告確定為靜脈瘤。超高頻生物顯微鏡在此類結膜下病灶提供了相當清楚的影像，對於診斷有很大的幫助。 We present a 24 -year-old woman with an orbital varix presented as a subconjunctival mass in her left eye. The computed tomography (CT) failed to demonstrate the lesion. Ultrasound biomicroscopy (UBM) showed acousticcally solid dome-shape lesion with moderate internal reflectivity, which was well demarcated from conjunctiva and sclera without extrascleral extension. Surgery was performed for cosmetic reason and pathology was compatible with varix. UBM was found to be invaluable to examine the subconjunctival pigmented lesion and to show the relationship to adjacent structures
Correlation between Refractive and Measured Corneal Power Changes after Myopic Excimer Laser Photorefractive Surgery
No full textPurpose: To determine the correlation between the refractive and measured corneal power changes after myopic photorefractive surgery.Setting: Department of Ophthalmology , National Taiwan University Hospital, Taipei, Taiwan. Methods: Eighty-six eyes that had myopic photorefractive surgery were analyzed. The data included preoperative and 1- year postoperative subjective refraction, standard automated keratometry, and computerized video keratography. Statistical analysis was performed to determine the relationship between the changes in subjective refraction in the corneal plane (DeltaSEQco) and in 4 corneal power measurements including the power measured by automated keratometry (DeltaAuto K), topographic-simulated keratometric power (DeltaSim K), the power of the first photokeratoscopic ring on videokeratography (DeltaCentral K) , and the average videokeratographic power on the pupil margin (DeltaPupil K). Results: The measured corneal power always underestimated the DeltaSEQco, with DeltaSEQco > DeltaCentral K > DeltaSim K > DeltaPupil K > DeltaAuto K. All the changes in measured corneal power could predict the DeltaSEQco with more than 90.00% (90.19% to 92.31 %) reliability at 1 year as calculated by the regression formulas (P <.001). The underestimation of measured corneal power changes was correlated with the amount of myopic correction, especially the Auto K (all P <.001). Conclusions : Direct corneal power measurements using automatic keratometry underestimated the actual corneal flattening after photorefractive surgery, which could be adjusted by a linear regression formula. Measuring the power of the first photokeratoscopic ring on videokeratography might provide a better estimation of actual corneal flattening after photorefractive surgery
Laser in Situ Keratomileusis for the Correction of Myopia and Myopic Astigmatism
No full textPurpose: To evaluate the efficacy, safety, predictability, and surgically induced astigmatism (SIA) of laser in situ keratomileusis (LASIK) for the correction of myopia and myopic astigmatism. Setting: Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan. Methods : This retrospective study comprised 69 eyes that had LASIK to correct myopia and 74 eyes that had LASIK to correct myopic astigmatism. The excimer laser keratectomy was performed using a Summit Apex Plus((R)) machine. Refraction, visual acuity, and computerized corneal videokeratography data from the preoperative and postoperative examinations were collected, The astigmatic change was calculated by the Alpins vector analysis method. Results: The preoperative spherical equivalent at the glasses plane in the myopia and myopic astigmatism groups was -8.08 diopters (D) and -9.73 D , respectively. At 6 months, the spherical equivalent and residual corneal astigmatism were -0.25 D and 0. 85 D, respectively, in the myopia group and -0.71 D and 0.82 D, respectively, in the myopic astigmatism group. In the myopia group, 88% of eyes were within +/- 1.0 D of the intended myopia correction and in the myopic astigmatism group, 85% were within +/- 1.0 D of the targeted spherical equivalent and 90% were within +/- 1.0 D of the intended astigmatism correction. The uncorrected visual acuity was 20/40 or better in 94.1% of eyes in the myopia group and 92.5% of eyes in the myopic astigmatism group. The SIA magnitude was 0.66 D with the axis randomly distributed in the myopia group. The mean astigmatism correction index was 0.97, the mean magnitude of error was 0.13 D +/- 0.62 (SD), and the mean angle of error was -3.70 +/- 13.73 degrees in the myopic astigmatism group . Conclusion: Laser in situ keratomileusis had similar predictability, safety, and efficacy in the treatment of myopia and myopic astigmatism, The astigmatism correction was effective, but the results suggest that subjective astigmatism of less than 1.0 D need not be treated with the Summit Apex Plus laser. (C) 2001 ASCRS and ESCRS
Clinicopathologic Study of Satellite Lesions in Nontuberculous Mycobacterial Keratitis
No full textMultifocal stromal infiltrates or "satellite lesions" have been considered a characteristic feature of fungal keratitis . We examined two patients with nontuberculous mycobacterial keratitis who clinically presented with satellite lesions. The keratitis consisted of multifocal stromal infiltrates with indistinct white and fluffy margins. Both patients received topical fortified amikacin therapy with poor response. Lamellar keratectomy or penetrating keratoplasty was performed, respectively, in the two patients because of progressive stromal thinning and enlarging satellite lesions . Histopathologically, the main lesions consisted of dense infiltration of inflammatory cells with numerous acid- fast bacilli, while the satellite lesions were composed chiefly of inflammatory cells with fewer mycobacteria. Besides fungal keratitis, nontuberculous mycobacterial keratitis should also be considered when satellite lesions are present
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