Finite element analysis of neodymium: yttrium-aluminum-garnet incisions for the prevention of anterior capsule contraction syndrome / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Anterior capsular contraction syndrome is a potential complication of continuous curvilinear capsulorhexis (CCC). Three neodymium: yttrium-aluminum-garnet (Nd:YAG) laser relaxing incisions decrease anterior capsular contraction but the mechanism is unknown. The present study analyzed the biomechanical mechanism of three Nd:YAG laser relaxing incisions made to reduce anterior capsular contraction.</p><p><b>METHODS</b>A three-dimensional control model and a three-dimensional Nd:YAG model of the anterior capsule with an opening diameter of 6 mm were created. Three incisions of 1 mm in length were made centrifugally at intervals of 120° around the opening circle. The stress alterations of the anterior capsule after CCC with and without Nd:YAG relaxation were numerically simulated and compared.</p><p><b>RESULTS</b>In the control model, the stress was axially uniform in the inner area and relatively high near the inner rim of the opening. Meanwhile, in the Nd:YAG model, the stress level was very low in the inner opening areas, especially near the three incisions. The relaxing incisions in the Nd:YAG model significantly released the relatively high stress on the anterior capsule. Additionally, there was a high stress gradient near the relaxing incisions.</p><p><b>CONCLUSION</b>Biomechanical effects of stress release may be the preventive mechanism of Nd:YAG incision against anterior capsular contraction syndrome.</p>

Determination of drug concentration in aqueous humor of cataract patients administered gatifloxacin ophthalmic gel / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Ophthalmic gel has been developed to increase the drug concentration in aqueous humor and to retard the loss of drug from the conjunctival sac. The research was to compare the drug concentration in aqueous humor of cataract patients administered 0.3% gatifloxacin ophthalmic gel with that in patients administered 0.3% gatifloxacin ophthalmic solution.</p><p><b>METHODS</b>Ninety-six patients with cataract (96 eyes) were randomly assigned to 8 groups. The patients in groups 1-4 received topical gatifloxacin 0.3% ophthalmic gel and those in groups 5-8 received gatifloxacin 0.3% ophthalmic solution. The dose regimen was 1 drop, 4 times a day for 3 consecutive days prior to cataract surgery. On the day of surgery, 1 drop was applied at 15, 30, 60 or 120 minutes before commencement of cataract surgery in groups 1 and 5, groups 2 and 6, groups 3 and 7, and groups 4 and 8, respectively. Aqueous humor was extracted during the cataract surgery for the analysis of gatifloxacin concentration..</p><p><b>RESULTS</b>The concentrations of gatifloxacin in aqueous humor were (0.24 +/- 0.25) microg/ml, (1.11 +/- 0.74) microg/ml, (2.32 +/- 2.01) microg/ml and (1.85 +/- 1.14) microg/ml in groups 1 to 4, and (0.16 +/- 0.25) microg/ml, (0.31 +/- 0.24) microg/ml, (0.75 +/- 0.28) microg/ml and (0.33 +/- 0.22) microg/ml in groups 5 to 8, respectively. Patients receiving gatifloxacin ophthalmic gel showed greater mean values of gatifloxacin concentration in aqueous humor than those receiving gatifloxacin solution, and such differences were significant with P < 0.05 for all comparisons except that between groups 1 and 5.</p><p><b>CONCLUSION</b>Topical gatifloxacin ophthalmic gel can attain significantly greater drug concentrations in human aqueous humor than gatifloxacin ophthalmic solution.</p>

Five years evaluation of laser in situ keratomileusis for myopia / 眼科

Objective To evaluate five years results of laser in situ keratomileusis(LASIK)for correction of myopia.Design Ret- rospective case series.Participant 64 patients(126 eyes)with myopia received operation of LASIK.Method 126 myopic eyes were treated with LASIK.Based on the preoperative spherical equivalent refraction(SER),the patients were divided into Group A,B and C(-3.00D～6.00D,-6.25D～-10.00D and -10.38D～-19.88D).Before and after operation,the visual acuity,refraction,anterior seg- ment,funduscopy,intraocular pressures of patients were measured,and the patients were followed-up five years.Main Outcome Measure Visual acuity,intraocular pressure,refraction and complication.Result At five years,in Group A,B,C,uncorrected visual acuity was≥1.0 in 87.2%,69.1%,31.3% patients,and 100%,98.2%,75% had vision of≥0.5.After five years of operation,the re- fraction was -0.70D?0.52D,-1.06?0.13D,-2.46?2.14D in three groups respectively,there was no significant difference between Group A and B(P=0.23);But there was significant statistical difference between Gruop A and C(P=0.008),Group B and C(P=0.021)respec- tively.At the fifth-year,68.3%,45.0% and 23.5% of refraction in Group A,B,C were within?1.00D.Intraocular pressure at the fifth year was 11.91?2.35mmHg,11.31?2.20 mmHg and 9.24?2.20 mmHg respectively.In Gruop B and C,one patient complained glare re- spectively.In Gruop B,one patient's intraecular pressure was elevated after using glueocorticoid.In Group C,one eye was complicated with rbegmatogenous retinal detachment at the second year after LASIK.Conclusion In the follow-up of five years,LASIK is effective and safe.The results in middle and high myopia are better than that in extreme high myopia.(Ophthalmol CHN,2006,15:312-314)