ABSTRACT
·AIM: To observe the efficacy and safety of a new posterior chamber intraocular lens ( ICMO V4c ) implantation in patients with high myopia and low astigmatism and to provide reference for the clinical diagnosis and treatment of these patients. ·METHODS: The study was to analyze the clinical data of patients with high myopia who underwent ICMO V4c implantation with low degree of astigmatism in our hospital from January 2015 to December 2016. The patients were followed up for 1, 3 and 6mo after operation. The items we analyzed including preoperative and postoperative uncorrected visual acuity ( UCVA) and best corrected visual acuity ( BCVA), diopter, spherical and cylinder equivalent, and manifest refraction spherical equivalent ( MRSE ), intraocular pressure ( IOP ), endothelial cell counting, anterior chamber depth (ACD), arch height and postoperative complications. ·RESULTS: Postoperative UCVA and BCVA improved compared with preoperative, and the difference between preoperative and postoperative was statistically significant (P<0. 05). All spherical and cylinder equivalent, and MRSE were reduced after surgery ( t = 38. 510, 20. 100, 34. 300; P<0. 01). The mean intraocular pressure increased at 1 and 3mo after operation ( t= 3. 998, 2. 837, all P<0. 05), but it returned to normal at 6mo ( t=0. 383, P>0. 05). The corneal endothelium counts in the patients at 3mo and 6mo after surgery were lower than those before surgery (t= 2. 119, 2. 411; all P<0. 05). The depth of anterior chamber was reduced to a certain extent within 6mo after operation, and recovered after surgery at 6mo after surgery, but it was still lower than the preoperative level (t=5. 850, 5. 260, 2. 556; all P<0. 05). The overall level of ocular arch after operation was stable and no significant fluctuations were observed. The incidence of postoperative complications in the surgical eye was low and significantly improved after active treatment. ·CONCLUSION: The new posterior chamber intraocular lens implantation in the treatment of high myopia with low astigmatism reaches satisfaction with less complications, is a good supplement to corneal refractive surgery.
ABSTRACT
Background The application of femtosecond laser in the corneal refractive surgery has made great progression recent years,but the morphology characteristic of corneal stroma surface after making-flap of femtosecond laser is closely concerned.Objective This study was to analyze the influence of photodisrnption of femtosecond laser on the corneal stroma surface and to investigate the effect of different laser pulse energy on the sudace ultrastructure of corneal stroma.Methods Corneal flaps were made with Visu Max femtosecond laser in 16 fresh porcine eyes with the pulse energy 125 nJ,155 nJ and 195 nJ respectively,and Moria-M2 microkeratome was used as control.Scanning electron microscopy (S-3400N Hitachi High-Technologies Corp) was used to observe and compare the ultrastructural characteristic of corneal stroma bed surface after making of corneal flap.Results The corneal strnma was evaporated and created a smooth surface when photodisrnption happened in the femtosecond laser group.Residual tissue bridges could been exhibited among the cavitation bubbles under the scanning electron microscope.Corneal strnma surface was smooth in the 125 nJ pulse energy group,but some tissue bridges still were visible.In the 155 nJ pulse energy group,much more smooth surface was seen without tissue bridges and mechanical damages on the corneal surface.However,the surface quality was worse and many tissue bridges and grooves existed in the 195 nJ pulse energy group.In addition,different sizes of slots caused by big cavitation bubbles were visible with the round and oval shape.The edges were regular and sharp with small damage zone after cutting with femtoseeond laser.However,many elevated fibril tissues could be seen on the corneal surface after making of flap with microkeratome.Many crimp and irregularity tissues were found on the surface.Blunt surface and indentations appeared in the cutting edge.Conclusions The mierostrueture of corneal stroma surface is more smoother after making of corneal flap with fentosecond laser in comparison with microkeratome.Pulse energy of 155 nJ is preferably during the making-flap with femtosecond laser.