共查询到20条相似文献,搜索用时 0 毫秒
1.
2.
Bernardo de Padua Soares Bezerra Elsie Chan Rahul Chakrabarti Rasik B. Vajpayee 《Survey of ophthalmology》2019,64(5):639-646
Measurement of intraocular pressure is an integral part of a comprehensive ocular examination, especially after a surgical intervention that can affect aqueous humor flow dynamics. Most of the intraocular pressure measurement devices are designed for “normal” corneas and may not be accurate in eyes after corneal transplantation where there is altered corneal morphology. Raised intraocular pressure and glaucoma are known postoperative complications after transplantation, and therefore, accurate intraocular pressure measurement is essential. We review the effect of abnormal corneal curvature, corneal thickness, and different biomechanical properties in the context of corneal transplantation on intraocular pressure measurement using a number of devices. 相似文献
3.
D K Holmes-Higgin T E Burris P A Asbell D S Durrie D J Schanzlin 《Journal of refractive surgery (Thorofare, N.J. : 1995)》1999,15(3):324-330
PURPOSE: To evaluate predicted optical quality of the central anterior corneal surface before and after the intrastromal corneal ring segment (ICRS) refractive procedure using a clinical videokeratoscope and software index developed for that purpose. METHODS: Predicted corneal acuity, a topographically derived index provided with the EyeSys System 2000 videokeratscope, representing potential optical quality of the cornea, was assessed preoperatively and at postoperative month 3 in 94 eyes that received an ICRS to treat -1.00 to -6.00 D of myopia. Predicted corneal acuity was calculated by determining the difference between a measured cornea and its best-fit ellipses for reflected ring circumferences within the central 3 mm diameter zone. RESULTS: Preoperative predicted corneal acuity was 20/10 in 92 of 94 eyes (98%). At month 3 after the ICRS procedure, 48 (51%) of moderately myopic eyes were corrected to 20/20 or better, 96% (90 eyes) were corrected to 20/40 or better, and 98% of eyes (92 eyes) had a predicted corneal acuity of 20/10. For the eyes with a predicted corneal acuity of 20/10, spectacle-corrected visual acuity was normally distributed between 20/10 and 20/25. CONCLUSION: Predicted corneal acuity did not change significantly from baseline in eyes with an ICRS. This suggests that topographic irregularities in the central 3 mm of the cornea detectable by predicted corneal acuity software were not induced in the central cornea with the ICRS. 相似文献
4.
Characterization of the aspheric corneal surface with intrastromal corneal ring segments. 总被引:1,自引:0,他引:1
D K Holmes-Higgin P C Baker T E Burris T A Silvestrini 《Journal of refractive surgery (Thorofare, N.J. : 1995)》1999,15(5):520-528
PURPOSE: Anterior corneal surface asphericity was examined in eyes of Phase II clinical trial participants, before and after intrastromal corneal ring segments (ICRS, Intacs) refractive surgery, and surveyed for relationship to clinical visual performance. METHODS: Aspheric test objects with surface asphericity (Q) ranging from -0.01 Q to -1.44 Q and base radius of curvatures ranging from 7.5 mm to 9.0 mm were measured topographically using videokeratography. Radius of curvature asphericity profile plots were produced for test objects and compared to similar plots created for trial participant eyes (n=25) to quantify corneal asphericity. The potential effects of different amounts of corneal asphericity were assessed using measurement of uncorrected and spectacle-corrected visual acuity and photopic contrast sensitivity. RESULTS: Preoperative corneal asphericity ranged from -0.01 Q to -0.81 Q and postoperative from -0.01 Q to -1.44 Q. Preoperative uncorrected visual acuity was significantly related to corneal asphericity; more myopic eyes tended to have more prolate corneal asphericity. Corneal asphericity was not significantly related to spectacle-corrected visual acuity or photopic contrast sensitivity, before or after surgery. CONCLUSION: Postoperative corneal asphericity values demonstrated that intrastromal corneal ring segments (Intacs) produced a prolate aspheric surface for myopic correction from -1.00 D to -6.00 D. This study indicated that the range of corneal asphericity measured in these 25 eyes, before and after surgery, provided good visual acuity and normal contrast sensitivity. 相似文献
5.
Hellstedt T Mäkelä J Uusitalo R Emre S Uusitalo R 《Journal of refractive surgery (Thorofare, N.J. : 1995)》2005,21(3):236-246
PURPOSE: To assess the safety and efficacy of Intacs inserts for the treatment of mild to moderate keratoconus. METHODS: In a nonrandomized prospective clinical trial, 50 eyes of 37 patients with mild to moderate keratoconus were implanted with asymmetrical pairs of Intacs segments. Patients were interviewed and observed preoperatively and 24 hours, 1 week, 1, 3, 6, and 12 months postoperatively. Main outcome measures were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, satisfaction with vision and trouble with vision, Visual Function-7 score, and surgically induced change in corneal astigmatism. RESULTS: Of the 50 operations performed, 92% were successful. Mean follow-up was 6.3 +/- 3.2 months. In 4 (8%) eyes, both Intacs segments were removed. In addition, 7 refractive adjustments in 7 eyes were performed successfully to improve visual and surgical outcome. Both BSCVA and UCVA improved throughout follow-up. Visual functioning index improved from 61.6 +/- 21.1 to 80.8 +/- 22.5, and the percentage of satisfaction with vision improved from 24.3% to 87.5% at 12 months. Vector analysis of astigmatism correction showed that the mean change in corneal astigmatism was 2.9 +/- 2.9 D at 6 months postoperatively. By selecting patients in whom astigmatism correction was best (index of success >0.5), an analysis was performed to determine individual factors important in successful surgery. Preoperatively these 11 (22%) eyes did not differ significantly from the remaining eyes and the only significant value was low K readings in the flat axis. CONCLUSIONS: Asymmetric Intacs placement improves BSCVA and UCVA and reduces astigmatism in patients with mild to moderate keratoconus. The procedure of Intacs placement is safe and effective. The change in astigmatism correction is unpredictable. 相似文献
6.
8.
Leonardo Torquetti Guilherme Ferrar Franklin Almei Leandro Cunh Paulo Ferrar Jesús Merayo-Lloves 《国际眼科杂志》2013,13(6):796-800
AIM:To evaluate the clinical outcomes after Ferrara intrastromal corneal ring segments (ICRS) reoperation in patients with keratoconus.RESULTS: The mean follow-up time after the reoperation was 30.5±9.7 months. The mean UCVA improved from 20/300 to 20/80 (P=0.005); the mean BCVA improved from 20/160 to 20/50 (P=0.0002), the mean keratometry reduced from 49.33±4.19D to 46.16±3.90D (P=0.0001), the mean pachymetry at the thinnest point increased from 450±42.9mm to 469±40.8mm (P=0.0001). The asphericity increased from -0.84±0.74 to -0.35±0.81 (P=0.15) and the spherical equivalent reduced from -4.64±4.87D to -3.04±3.45D (P=0.137). The changes in the asphericity and spherical equivalent were not statistically significant.CONCLUSION: Ferrara ICRS implantation showed to be a reversible and readjustable surgical procedure for keratoconus treatment. Good outcomes can be obtained even after removal, addition, reposition or exchange of ICRS. 相似文献
9.
Abdullhamid Alghamdi 《国际眼科》2020,1(3):140-144
AIM: To evaluate the clinical effectiveness of intrastromal corneal ring segments (ICRS) among the patients suffering from keratoconus.
METHODS: A retrospective and non-comparative interventional design had been utilized on the basis of postoperative follow-up among 56 keratoconus patients. Visual acuity was significantly assessed during complete ophthalmic examination of the patients. The femtosecond laser had been used to create the corneal tunnels in 15 eyes; whereas, the corneal tunnels were created in 72 eyes mechanically.
RESULTS: The ranges and standard deviations had been used to obtain results. It had been revealed through ophthalmic assessment that the mean preoperative uncorrected visual acuity observed was 1.38±0.37 logarithm of Minimal Angle of Resolution. Moreover, a significant improvement was observed postoperatively in visual acuity by 0.58±0.32 during the 4th month. The improvement was also witnessed in the 16th month by 0.48±0.30.
CONCLUSION: The implantation of ICRS is an efficient and effective surgical intervention for the treatment of keratoconus. Thus, identified intervention seems to be associated with appropriate visual outcomes and safety after the development of femtosecond as well as mechanical tunnels. 相似文献
10.
Cheng AC Leung DY Cheung EY Fan DS Law RW Lam DS 《Clinical & experimental ophthalmology》2005,33(2):153-157
PURPOSE: To compare intraocular pressure (IOP) assessment in post-LASIK patients using non-contact tonometry, pressure phosphene tonometry and applanation tonometry. METHODS: Sixty-two consecutive LASIK patients were analysed preoperatively and postoperatively with non-contact, pressure phosphene and applanation tonometry. Comparisons among these values were assessed with paired sample Student t-test, Pearson's correlation test and Bland-Altman plotting. RESULTS: There was no significant difference for preoperative IOP measurement between non-contact, pressure phosphene and applanation tonometry. The mean +/-SD difference between the preoperative non-contact tonometry and postoperative pressure phosphene tonometry IOP measurements was 0.80 +/- 2.77 mmHg (P < 0.01). Postoperative applanation tonometry significantly underestimated IOP measurement by 5.45 +/- 2.96 mmHg (P < 0.001) and postoperative non-contact tonometry significantly underestimated IOP measurement by 9.96 +/- 2.25 mmHg (P < 0.001). CONCLUSION: Pressure phosphene tonometry may provide an alternative method for the assessment of IOP in post-LASIK patients. 相似文献
11.
Bourges JL Trong TT Ellies P Briat B Renard G 《Journal of cataract and refractive surgery》2003,29(6):1228-1230
Poly(methyl methacrylate) refractive intracorneal ring segments (ICRS) can be removed for a refractive miscorrection or for early complications after implantation. We report the first case of a woman who experienced anterior stromal necrosis 5 years after an ICRS surgical procedure. 相似文献
12.
13.
14.
15.
Intraocular pressure measurement after hyperopic LASIK. 总被引:2,自引:0,他引:2
Xiaohong Wang Joanne Shen James P McCulley R Wayne Bowman W Matthew Petroll H Dwight Cavanagh 《The CLAO journal》2002,28(3):136-139
PURPOSE: Previous studies have shown that Goldmann applanation tonometry (GAT) underestimates intraocular pressure (IOP) following photorefractive keratometry (PRK) and myopic laser in situ keratomileusis (LASIK). The purpose of this study was to evaluate the reliability of intraocular pressure (IOP) measurements by Goldmann applanation tonometry and pneumotonometry (PT) after hyperopic LASIK. METHODS: The IOPs of 20 eyes of 15 patients who underwent hyperopia LASIK were prospectively evaluated. Central and peripheral IOP were measured with GAT and PT, and central and peripheral corneal thicknesses were measured with ultrasonographic pachymetry. Patients were evaluated preoperatively and at 12 months postoperatively. RESULTS: Postoperative GAT measurements of IOP made from the central (13.1+/-2.7 mm Hg) and peripheral (13.9+/-3.3 mm Hg) corneal areas were significantly lower (P <0.001) than central IOP measured preoperatively (17.0+/-2.5 mm Hg). Postoperative PT measurements from the central (17.4+/-3.2 mm Hg) and peripheral (17.6+/-2.9 mm Hg) corneal areas were slightly lower than preoperative central IOP (18.4+/-2.4 mm Hg), but not statistically significant. There were no significant differences between central and peripheral IOP measurements using either method. CONCLUSION: The data demonstrate that GAT may underestimate IOP measurement, following hyperopic LASIK. 相似文献
16.
Intraocular pressure was estimated in patients with corneal disorders and secondary glaucoma. 25 patients (29 eyes) with complicated corneal opacities and secondary glaucoma were included into the study. In these patients the most reliable results were revealed using bidirectional corneal applanation (ORA) with contact lens on a cornea. If ORA is not available tonometer TGDc01-diaton should be used. 相似文献
17.
角膜基质环植入术(ICRS)是一种用于治疗轻中度圆锥角膜的手术方法。ICRS是通过植入基质环,使中央角膜扁平化,弧长缩短,角膜曲率半径增大,屈光力降低,从而改善角膜前突导致的轴性近视眼与不规则散光。ICRS具有微创性、安全性、有效性、可逆性且并发症少等优点,其中长期疗效较佳。本文中笔者就ICRS的发展史、适应症、手术方法、手术疗效的影响因素、术后处理及疗效的评估等方面进行阐述。 相似文献
18.
19.