Optical and visual quality comparison of implantable collamer lens and femtosecond laser assisted laser in situ keratomileusis for high myopia correction

AIM:To compare clinical outcomes and refractive stability of implantable collamer lens(ICL)implantation and femtosecond laser assisted laser in situ keratomileusis(FSLASIK)for high myopia correction.METHODS:The Optical Quality Analysis System(OQAS)was used to evaluate clinical outcomes objectively after operation for high myopia correction.We compared the two procedures in terms of 1-year changes in uncorrected distance visual acuity(UDVA),corrected distance visual acuity(CDVA),safety index,efficacy index,spherical equivalent,modulation transfer function(MTF)cutoff frequency,strehl ratio(SR)and objective scatter index(OSI).RESULTS:At 1 y postoperatively,the safety indices were 1.33±0.27 in ICL group,and 1.17±0.24 in FS-LASIK group.39.58%in the ICL group and 27.59%in the FS-LASIK group gained CDVA in 2 lines or better than that in preoperative CDVA.The efficacy indices were 1.28±0.22 in ICL group,and 1.13±0.26 in FS-LASIK group.The changes of spherical equivalent from 1 wk to 1 y postoperatively was-0.12±0.37 D in ICL group,and-0.79±0.58 D in FS-LASIK group(P<0.05).Spherical equivalent within±0.50 D was achieved in 97.92%in ICL group and 68.97%in FS-LASIK group.MTF cutoff frequency were higher with ICL as compared to FSLASIK(P<0.05)at each postoperative follow-up stage;for postoperative 1 mo later,SR was statistically significant difference between two groups(P<0.05);with no statistically significant difference in OSI between two groups(P>0.05)in postoperative 3 mo later.CONCLUSION:ICL implantation and FS-LASIK procedures both provide good safety and predictability in high myopia correction.ICL implantation provides better clinical outcomes and refractive stability than FS-LASIK.

Early changes in corneal densitometry after FS-LASIK combined with accelerated corneal cross-linking for correction of high myopia

AIM:To observe the effects of femtosecond laserassisted excimer laser in situ keratomileusis combined with accelerated corneal cross-linking(FS-LASIK Xtra)on corneal densitometry after correcting for high myopia.METHODS:In this prospectively study,130 patients underwent FS-LASIK or FS-LASIK Xtra for high myopia.Their right eyes were selected for inclusion in the study,of which 65 cases of 65 eyes in the FS-LASIK group,65 patients with 65 eyes in the FS-LASIK Xtra group.Patients were evaluated for corneal densitometry at 1,3,and 6mo postoperatively using Pentacam Scheimpflug imaging.RESULTS:Preoperative differences in corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups in different ranges were not statistically significant(P>0.05).Layer-by-layer analysis revealed statistically significant differences in the anterior(120μm),central,and total layer corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups at 1 and 3mo postoperatively(all P<0.05),the FS-LASIK Xtra group is higher than that of the FS-LASIK group.Analysis of different diameter ranges showed statistically significant differences between the FS-LASIK group and the FS-LASIK Xtra group at 1mo postoperatively in the ranges of 0–2,2–6,and 6–10 mm(both P<0.05);At 3mo postoperatively,the FS-LASIK Xtra group is higher than that of the FS-LASIK group in the ranges of 0–2 and 2–6 mm(P<0.05).At 6mo postoperatively,there were no statistically significant differences in corneal densitometry between the FS-LASIK group and the FS-LASIK Xtra group in different diameter ranges(all P>0.05).CONCLUSION:There is an increase in internal corneal densitometry during the early postoperative period after FS-LASIK Xtra for correction of high myopia.However,the densitometry values decreased to the level of conventional FS-LASIK at 6mo after surgery,with the most significant changes observed in the superficial central zone.

Using LaserSight Astrapro Planner 2.2 Z software in corneal topography-guided laser in situ keratomileusis for myopia with asymmetric corneal shape

AIM:To determine the clinical outcomes of laser insitu keratomileusis(LASIK)treatments using LaserSight AstraPro Planner 2.2 Z software for myopia with asymmetric corneal shape.METHODS:Four hundred and eighty-five eyes[243patients;spherical equivalent(SE),-5.93±1.88 diopters(D)]were treated with asymmetric ablations using LaserSight SLX laser(version 5.3,300Hz)were retrospectively analyzed and LaserSight AstraPro Planner2.2 Z software.Preoperative and postoperative uncorrected visual acuities(UCVA),spherical equivalent(SE)refraction,pachymetry,and corneal asphericity(Q value)and decentration were evaluated.RESULTS:At 12mo postoperatively,the decimal UCVA was 1.0 or better in 449(92.6%)eyes.Two eyes(0.4%)lost 1 line of the decimal best spectacle-corrected visual acuity(BCVA),316(65.2%)did not change,149(30.7%)gained 1 line,and 18(3.7%)gained 2 lines or more after surgery.Three hundred and thirty-two eyes(68.5%)were within 0.5 D in SE.The mean tissue saving ablation depth was 4.28±2.86(0-16)μm(median,4μm).The mean attempted remaining central corneal thickness was435.79±29.56μm,the mean postoperative pachymetry was 444.94±28.93μm.The mean preoperative Q value was-0.19±0.18,the postoperative was 0.30±0.48(P=0.000).The mean postoperative decentration was 0.39±0.19 mm.CONCLUSION:Topography-guidedLASIKwithAstraPro Planner 2.2 Z custom ablation planning software in an asymmetric ablation mode was an effective,safe,predictable,and stable refractive procedure for the myopia with asymmetric corneal topography.

DIOPTER REGRESSION ANALYSIS OF LASER IN SITU KERATOMILEUSIS IN THE TREATMENT OF MYOPIA

Objective To evaluate the relevant factors of regression phenomenon of laser in situ kerato-mileusis (LASIK) for treatment of myopia. Methods We studied 408 eyes of 250 myopic patients who received LASIK. Patients were divided into 2 groups according to preoperative diopters (- 6 .00D- -10 .00D, 194 eyes;-10.10D- -15 .00D, 214 eyes). Mean period of follow-up were 12 months and the results were statistically analyzed. Results 12 months after surgery, in the first group (- 6.00--10.00D) the regressionequal to or beyond -1 .0D were 21 eyes (10.8%), range from -1 .0D to - 3 .0D. The average regression was -1.33D. In the second group (- 10 .10D - - 15 .00D) regression equal to or beyond -1.0D were 78 eyes (36.5%), range from -1 .0D to -5.50D. The average regression was -1 .99D. Conclusion The results indicate that excimer LASIK can be used to treat myopia between -6 .00D-- 15 .00D effectively with minimal regression within 12 months. Preoperative thin corneas with intraoperative small ablation zone could induce regression . Some modification of the surgical algorithms and laser nomogram will help to improve predictability and reduce regression.

Clinical outcomes of small incision lenticule extraction versus femtosecond laser-assisted LASIK for myopia: a Meta-analysis

AIM：To evaluate the possible differences in visual quality between small incision lenticule extraction（SMILE）and femtosecond laser in situ keratomileusis（FS-LASIK）for myopia.METHODS：A Meta-analysis was performed.Patients were from previously reported comparative studies treated with SMILE versus FS-LASIK.The Pub Med,EMBASE,Cochrane,Web of Science and Chinese databases（i.e.WANFANG and CNKI）were searched in Nov.of 2016 using Rev Man 5.1 version software.The differences in visual acuity,aberration and biomechanical effects within six months postoperatively were showed.Twenty-seven studies including 4223 eyes were included.RESULTS：No significant differences were observed between SMILE and FS-LASIK in terms of the proportion of eyes that lost one or more lines of corrected distance visual acuity after surgery（P=0.14）,the proportion of eyes achieving an uncorrected distance visual acuity of 20/20or better（P=0.43）,the final refractive spherical equivalent（P=0.89）,the refractive spherical equivalent within±1.00diopter of the target values（P=0.80）,vertical coma（P=0.45）and horizontal coma（P=0.06）.Compared with the FSLASIK group,total higher-order aberration（P〈0.001）and spherical aberration（P〈0.001）were higher and the decrease in corneal hysteresis（P=0.0005）and corneal resistance factor（P=0.02）were lower in the SMILE group.CONCLUSION：SMILE and FS-LASIK are comparable in efficacy,safety and predictability for correcting myopia.However,the aberration in the SMILE group is superior to that in the FS-LASIK group,and the loss of biomechanical effects may occur less frequently after SMILE than after FS-LASIK.

Kappa angles in different positions in patients with myopia during LASIK

AIM： To investigate the difference in kappa angle between sitting and supine positions during laser-assisted in situ keratomileusis（LASIK）.·METHODS： A retrospective study was performed on395 eyes from 215 patients with myopia that received LASIK. Low, moderate, and high myopia groups were assigned according to diopters. The horizontal and vertical components of kappa angle in sitting position were measured before the operation, and in supine position during the operation. The data from the two positions were compared and the relationship between kappa angle and diopters were analyzed.· RESULTS： Two hundred and twenty-three eyes（56.5%） in sitting position and 343 eyes（86.8%） in supine position had positive kappa angles. There were no significant differences in horizontal and vertical components of kappa angle in the sitting position or horizontal components of kappa angle in the supine position between the three groups（P 〉0.05）. A significant difference in the vertical components of kappa angle in the supine position was seen in the three groups（P 〈0.01）. Differences in both horizontal and vertical components of kappa angles were significant between the sitting and supine positions. Positive correlations in both horizontal and vertical components of kappa angles（P 〈0.05） were found and vertical components of kappa angle in sitting and supine positions were negatively correlated with the degree of myopia（sitting position： r =-0.109; supine position： r =-0.172; P 〈0.05）.·CONCLUSION： There is a correlation in horizontal and vertical components of kappa angle in sitting and supine positions. Positive correlations in both horizontal and vertical components of kappa angle in sitting and supine positions till the end of the results. This result still needs further observation. Clinicians should take into account different postures when excimer laser surgery needs to be performed.

Comparison of correcting myopia and astigmatism with SMILE or FS-LASIK and postoperative higher-order aberrations

AIM:To compare the effect of myopia and astigmatism correction and postoperative change in higher-order aberration as results of receiving small-incision lenticule extraction(SMILE)and femtosecond laser-assisted in situ keratomileusis(FS-LASIK).METHODS:A prospective and non-randomized controlled study was conducted.The subjects are divided into two groups according to different operations received:229 eyes of 116 patients in the SMILE group and 168 eyes of 86 patients in the FS-LASIK group.All subjects were followed up for 3 mo by monitoring their uncorrected visual acuity(UCVA),best-corrected visual acuity(BCVA),spherical equivalent,higher-order aberrations,and the preoperative and postoperative complications.RESULTS:At 1 wk,1,and 3 mo post-surgery,224 eyes(97.8%),227 eyes(99.1%)and 229 eyes(100%)had UCVA≥20/20 in the SMILE group,while 165 eyes(98.2%),167 eyes(99.4%)and 167 eyes(99.4%)had UCVA≥20/20 in the FS-LASIK group,respectively(χ^(2)=0.146,2.135,and 1.124;all P>0.05).BCVA reduction was not observed in both groups at 1 and 3 mo of post-surgery(χ^(2)=0.734 and 1.898,P>0.05).There was no statistically significant difference in the spherical equivalent between the two groups at 1 and 3 mo post-surgery,though the percentage of the spherical equivalent within±0.50 D at 3 mo postsurgery was 98%in the SMILE group,which was higherthan that of the FS-LASIK group(92%,χ^(2)=1.872,P>0.05).The root mean square(RMS)values of total high-order aberration,coma,and spherical aberration of the two groups increased significantly in the early postoperative period and decreased after 3 mo,but the values were still higher than the preoperative levels(P<0.05);there was no significant difference between the two groups in the RMS values of total higher-order aberrations and specific higherorder aberrations(P>0.05).The incidence of complications in the SMILE group was lower than that in the FS-LASIK group(χ^(2)=14.52,P<0.05).CONCLUSION:SMILE and FS-LASIK can effectively treat myopia,significantly improve visual acuity,and increase the total high-order aberration,spherical aberration,and coma.The incidence of complications after SMILE is relatively low.

Long-term efficacy of excimer laser in situ keratomileusis in the management of children with high anisometropic amblyopia

Background Children with anisometropic amblyopia are often noncompliant with traditional treatment including spectacules and contact lenses. This study was to evaluate the long-term efficacy of excimer laser in situ keratomileusis （LASIK） for children with high anisometropic amblyopia. Methods A retrospective analysis of 24 children with high unilateral anisometropic amblyopia, who underwent LASIK during the period between August 2000 and September 2005 in our hospital, was conducted. The mean age of these children was （7.4±1.9） years （range 5-14 years） and the mean follow-up period was （33.3±14.2） months （range 18.5-74.2 months）. After LASIK, visual acuity, refraction and far or near stereoacuity were analyzed. Near stereoacuity was measured by the random-dot butterfly stereogram and the pre-school random-dot stereogram, while far stereoacuity was measured by the synoptophore with Yan＇s random-dot stereogram. Results Mean preoperative uncorrected visual acuity was 0.06±0.05, while mean postoperative uncorrected visual acuity was elevated to 0.43±0.33. Mean preoperative best-corrected visual acuity was 0.26±0.22, while mean postoperative best-corrected visual acuity was elevated to 0.67±0.40. For patients with myopic anisometropia, preoperative mean spherical equivalent refraction was （-8.01±2.70） D while postoperative value significantly reduced to （-1.32±2.47） D. For patients with hyperopic anisometropia, preoperative mean spherical equivalent refraction was （ 7.35±1.55） D while postoperative value significantly reduced to （3.30±0.86） D. These results demonstrated that there was statistical difference in these parameters between preoperative and postoperative tests. At the last follow-up, 20 patients had near stereoacuity, and the mean near stereoacuities measured by the random-dot butterfly stereogram and the preschool random-dot stereogram were （149.00±152.93）＂ and （201.05±235.94）＂, respectively. In contrast, 11 patients had far stereoacuity, and the mean far stereoacuity measured by the synoptophore was （210.91±217.51）. Three cases of patients developed mild corneal complications. Conclusion LASIK for the correction of high anisometropia in children with monocular amblyopia may be safe and effective, and this can help effectively conduct postoperative amblyopia training and improve the cure rate.

Visual differences in topography-guided versus wavefront-optimized LASIK in the treatment of myopia: a Meta-analysis

AIM: To investigate the potential differences between topography-guided(TG) and wavefront-optimized(WFO) laser in situ keratomileusis(LASIK) for the treatment of myopia.METHODS: A systematic literature search was performed to determine relevant trials comparing LASIK with TG and WFO from the time of library construction to August 2020, and The PubMed, Cochrane, Web of Science, EMBASE and Chinese databases(i.e. CNKI, CBM, WAN FANG and VIP) were accessed. The data on visual acuity, refractive status and wavefront aberration were retrieved and evaluated from three to six months after surgery. STATA(version 14.0) software was used for statistical analysis. A cumulative Meta-analysis was simultaneously performed.RESULTS: Eleven studies with a total of 1425 eyes were incorporated. No statistically significant differences were evident between TG and WFO ablation in the proportion of eyes achieving an uncorrected distance visual acuity(UCVA) of 20/20 or better(P=0.377), gaining one line or more(P=0.05), postoperative cylinder(P=0.40), vertical coma(P=0.593) and horizontal coma(P=0.957). After TG ablation, the proportion of the patients’ eyes of which postoperative refraction is within ±0.5 diopter of the target refraction was significantly higher than that undergoes WFO(P=0.003). As opposed to the WFO group, manifest refraction spherical equivalent(MRSE;P=0.000) was lower, and UCVA(P=0.005) was better in the TG group. The higher-order aberrations(HOAs;P=0.000), spherical aberration(P=0.000) and coma(P=0.000) were significantly lower in TG group. The cumulative Meta-analysis illustrated that the proportion of eyes achieving UCVA of 20/20 or better, postoperative refraction within ±0.5 diopter, and MRSE has steady between the two groups.CONCLUSION: Both TG-LASIK and WFO-LASIK are safe, effective, and predictable for correcting myopia. TG-LASIK may produce fewer aberration and is more precise than WFO-LASIK.

DIAGNOSIS AND TREATMENT FOR DEGENERATIVE RETINOSCHISIS OF MEDIUM TO HIGH MYOPIA IN YOUNG ADULTS PRIOR TO LASER-ASSISTED IN SITU KERATOMILEUSIS SURGERY

Objective To discuss the characteristics of degenerative retinoschisis in young adults with medium to high myopia prior to laser-assisted in situ keratomileusis(LASIX) surgery and the significance of preventive photocoagulation.Methods A total of 32 eyes in 19 patients suffering from myopia combined with degenerative retinoschisis were included.The mean best-corrected visual acuity was 0.82±0.13 and the mean spherical equivalent of the subjective refraction was -(6.50±3.98) Diopter. The patients underwent preventive photocoagulation 1 month before the laser surgery for myopia.Results All the eyes that received preventive photocoagulation for retinoschisis had no further progression or retinal detachment during 4-year period of follow-up.Conclusion The degenerative retinoschisis in young adults should be recognized and treated with preventive photocoagulation.This may prevent further damage of visual field and other complications of slowly progressive retinoschisis after LASIK surgery.

Comparison of visual acuity of the patients on the first day after sub-Bowman keratomileusis or laser in situ keratomileusis

AIM：To compare recovery of the visual acuity in patients one day after sub-Bowman keratomileusis（SBK）or laser in situ keratomileusis（LASIK）.· METHODS：Data from 5923 eyes in 2968 patients that received LASIK（2755 eyes） or SBK（3168 eyes） were retrospectively analyzed.The eyes were divided into 4groups according to preoperative spherical equivalent：between-12.00 to-9.00 D,extremely high myopia（n =396,including 192 and 204 in SBK and LASIK groups,respectively）;-9.00 to-6.00 D,high myopia（n=1822,including 991 and 831 in SBK and LASIK groups,respectively）,-6.00 to-3.00 D,moderate myopia（n=3071,including 1658 and 1413 in SBK and LASIK groups,respectively）,and-3.00 to 0.00 D,low myopia（n =634,including 327 and 307 in SBK and LASIK groups,respectively）.Uncorrected logMAR visual acuity values of patients were assessed under standard natural light.Analysis of variance was used for comparisons among different groups.· RESULTS：Uncorrected visual acuity values were0.0115±0.1051 and 0.0466±0.1477 at day 1 after operation for patients receiving SBK and LASIK,respectively（P〈0.01）;visual acuity values of 0.1854±0.1842,0.0615±0.1326,-0.0033±0.0978,and-0.0164±0.0972 were obtained for patients in the extremely high,high,moderate,and low myopia groups,respectively（P〈0.01）.In addition,significant differences in visual acuity at day 1 after operation were found between patients receiving SBK and LASIK in each myopia subgroup.· CONCLUSION：Compared with LASIK,SBK is safer and more effective,with faster recovery.Therefore,SBK is more likely to be accepted by patients than LASIK for better uncorrected visual acuity the day following operation.

Severe Diffuse Lamellar Keratitis Following Laser <i>in Situ</i>Keratomileusis with an Iatrogenic Double Flap

We present a case of an iatrogenic double flap created during laser in situ keratomileusis using a femtosecond laser microkeratome that resulted in development of severe diffuse lamellar keratitis (DLK). The DLK occurred mainly in the second interface, made by the spatula accidentally and not exposed to femtosecond or excimer lasers. Because of differences in the severity of the interface inflammatory reactions between the two layers exposed to the same spatula, an allergic reaction to detergent, bacteria, or other chemicals could not be assumed to be the main cause of DLK. Our observations in this case may suggest an important association of neural factors with DLK, because the inflammatory reaction occurred mainly in the deep stromal layer at the thick corneal nerves.

The Influence of Keratometry on Visual and Refractive Outcomes after Myopic LASER <i>in Situ</i>Keratomileusis

To evaluate the effect of preoperative keratometry on visual and refractive outcomes after Myopic LASER in Situ Keratomileusis (LASIK) in eyes with preoperative spherical equivalent (SE) of -6.00D or less. Material and Methods: A retrospective study enrolling clinical records of 482 eyes of 275 patients with myopia who underwent LASIK between 2009 and 2016. Subjects were grouped according to the degree of preoperative mean keratometry (Km), into three groups: Group 1 (Flat Cornea): Km ≤ 42.00 diopters (D);Group 2: 42.00 46.00D;Group 3 (Steep Cornea): Km ≥ 46.00D. To evaluate the prognostic impact of keratometry in Myopic LASIK, we considered the results measured at 6 months postoperatively, including uncorrected distance visual acuity (UDVA), postoperative sphere, cylinder, SE and its variation. Results: The mean preoperative SE was -3.91 ± 1.54D, ranging between -0.88 and -6.00D. The percentage of eyes achieving a postoperative SE of ±0.50D was 39.5%, 31.8% and 26% in groups 1, 2 and 3 respectively. Moreover, in group 3, 14.3% of the eyes had a residual SE of -2.00D or greater, contrasting with the groups 1 and 2 with only 6% - 7%. These results were found to be statistically significant. Concerning UDVA, eyes achieving 20/25 or more were 81.5%, 81.8% and 71.5%, and 20/50 or less were 6.7%, 6.2% and 11.7% in groups 1, 2 and 3 respectively. Conclusions: Myopic eyes with steeper corneas seem to have greater tendency to undercorrection, also presenting worse visual outcomes.

Long term changes of posterior corneal elevation after myopic laser in situ keratomileusis

Background: Corneal ectasia is a serious complication after laser in situ keratomileusis(LASIK). Ideally, patients at risk of ectasia should be identified prior to laser as unsuitable for LASIK, however, at present, there is no absolute test, system, or marker that can unequivocally identify patients at risk of developing ectasia. It has been suggested that changes in the forward protrusion of the posterior cornea or posterior corneal elevation(PCE) may be a key to the early detection of ectasia after LASIK. The purpose of this study was to examine the long term changes of the PCE after myopic LASIK using the ORBSCAN~ IIz(Bausch & Lomb, Rochester, USA) and to evaluate the contributory preoperative factors to PCE changes.Methods: This was a retrospective longitudinal case series. Forty-two eyes of 23 consecutive myopic patients who underwent uneventful LASIK surgery 6 years ago were recalled for a postoperative follow-up examination using the ORBSCAN~ IIz to determine the elevation changes to the posterior corneal surface from the preoperative measurements. A forward shift of the posterior surface was given a negative value. Correlation analyses and forward stepwise regression analyses were performed to evaluate the effect of each of the preoperative parameters on the changes in PCE. Statistical and graphical analyses were performed.Results: There was no statistical difference between the mean best-fit sphere(BFS) pre-LASIK and 6 years postop(P=0.25). Forty-two post-LASIK eyes had a mean posterior displacement of -9.38±9.84 μm(range, 12 to-31 μm) 6 years after LASIK. Forward stepwise multiple linear regression analysis indicated that the ablation spherical equivalent(ASE) was the only indicator of the forward shift of the posterior cornea after LASIK.Conclusions: The present study identified a significant forward shift of the posterior cornea 6 years after LASIK. The ASE was the most significant prognostic determinant for forward protrusion of the posterior cornea after LASIK.

Evaluation of laser in situ keratomileusis for myopic correction performed under thin flaps

AIM： To evaluate the efficacy and safety of laser-assisted subepithelial keratectomy （LASIK） for myopic correction done under thin flaps（120μm） and compare with results obtained under thick flaps（150μm）.METHODS： The study included 150 myopic eyes of 75 patients without previous refractive surgery who underwent LASIK prospectively. Two microkeratome heads （90 and 130） were used to created a flap with thickness of 120μm and 150μm,respectively. Thin flap group（120μm） included 75 eyes while thick flap group included 75 eyes. Follow-up period was 12 mo. Efficacy,l safety, and stability were evaluated and compared between the two groups.RESULTS： In 150 eyes,the mean preoperative spherical equivalent refraction was -8.65±2.6D,mean sphere was -4.4±3.5D, and mean cylinder was -1.0±1.3D. THe amount of ablation was significantly larger in the thin flap （88.5±32.21μm） group than in the thick flap group （64±28.13μm）.Percentage of safety was higher in the thin flap group（94.8%） than in the thick flap group（91.7%）. There were no intraoperative complications, especially flap-related problems. Subjective symptoms of dry eye occurred in 20.7% and 33.3% of eyes in the thin and thick flap groups, respectively. CONCLUSION： Thin-flap LASIK is effective and safe in correcting myopic defects. It achivevs better visual results, rapid visual recovery, and stable postoperative refraction than LASIK with thick flaps.

ONE YEAR RESULTS OF LASER IN SITU KERATOMILEUSIS FOR CORRECTION OF HYPEROPIA

Objective: To evaluate the effectiveness, predictability and city of laser in situ keratomileusis (LASIK) for correction of hyperopia. Methods 54 eyes of 35 patients with hyperopia ranging from+1.00 to + 6. 00 diopter(D) received a one-pass, multizone scanning excimer laser ablations using the Chiron Technolas Keracor 11 7C excimer laser and System ALK automated corneal shaper H-230.Data on uncorrected and hot corrected visual acuity, predictability, stability of refraction, and complications were analyzed. The average follow-up was 12 months. Results At 12 months, the average residual refraction was(+ 0. 29 ±0. 78)D. 45 eyes (83.3% ) were in the range of ±1. OD and 33 eyes(61. 1% ) were within the range of ± 0. 5D. 50 eyes (92. 6% ) had uncorrected visual acuity of 20/40 or better and 34 eyes (63. 0% ) had 20/20 or better. 1 eyes (1. 9% ) lost 2 line of the best-corrected visual acuity and 2 eyes (3. 7% ) gained 2 lines or more. 2 eyes (3. 7%) had complaint of halos and 1 eyes (1. 9% ) had glare at 12 months. Conclusion LASIK can he used to treat hyperopia from + 1. 0D to + 6. 0D with good predictability and city. Primary and second hyperopia should he treated with different nomogram. some modification of the surgical algorithms and laser nomogram will help to improve predictability and stability of outcome.

Effect of open ultraviolet germicidal irradiation lamps on functionality of excimer lasers used in cornea surgery

We report on the impact of direct ultraviolet germicidal irradiation（UVGI）on reflective optics,used in the excimer laser system Allegretto Eye-Q.The aim of our work was to confirm our hypothesis based on long-rate observations of obtained anomalies in post-operative results that are attributed to degradation of reflective optics upon ultraviolet radiation.The presence of direct UVGI coupled with humidity in the operating environment caused merging anomalies and unwanted post-operative correction values.Ultraviolet-A radiation caused a similar effect on the reflective cover of the mirrors.

SMILE和WG-FS-LASIK治疗低度无散光近视患者术后早期视觉质量比较

目的比较飞秒激光小切口角膜基质内透镜取出术(SMILE)和波前像差引导的准分子激光原位角膜磨镶术(WG-FS-LASIK)治疗低度无散光近视患者术后的早期视觉质量。方法选择2022年3月至6月在广西壮族自治区人民医院视光中心行SMILE治疗的患者15例(30眼,SMILE组),行WG-FS-LASIK治疗的患者15例(30眼,WG-FS-LASIK组)。所有患者术前无散光且最佳矫正视力所需最低球镜度数均≤-3.00 D。于术前和术后1 d、1周、1个月测量视力、全眼像差(慧差、三叶草像差和球差)、客观散射指数(OSI)、调制传递函数截止频率(MTF_(cut-off))、斯特列尔比(SR)、可预测对比度视力(PVA)(包括PVA 100%、PVA 20%、PVA 9%)。比较两组观察指标测量结果。结果两组术后等效球镜、视力情况均较术前显著改善(P<0.05),但两组各时间点比较差异无统计学意义(P>0.05)。两组术后OSI、SR、PVA 9%均较术前显著改善(P<0.05)。WG-FS-LASIK组在术后1 d、1周、1个月的OSI水平均显著低于SMILE组(P<0.05)。在术后1个月,WG-FS-LASIK组PVA 9%显著高于SMILE组(P<0.05)。SMILE组和WG-FS-LASIK组术后慧差均呈先上升后下降的趋势,但WG-FS-LASIK组变化幅度更小,在术后1 d、1周、1个月,WG-FS-LASIK组慧差小于SMILE组,差异有统计学意义(P<0.05)。结论SMILE和WG-FS-LASIK均能提高低度无散光近视患者术后早期视觉质量,但WG-FS-LASIK早期视力恢复更好,且夜间视觉质量改善更优。

角膜地形图引导的飞秒制瓣准分子激光手术治疗近视合并散光患者的效果

目的:观察角膜地形图引导的飞秒制瓣准分子激光手术(FS-LASIK)治疗近视合并散光患者的效果。方法:选取2018年7月至2023年7月梅州爱尔眼科医院收治的68例(136只眼)近视合并散光患者进行前瞻性研究,按照随机数字表法将其分为对照组和观察组各34例(68只眼)。对照组实施普通FS-LASIK治疗,观察组实施角膜地形图引导的FS-LASIK治疗。比较两组治疗前后视力[裸眼视力(UCVA)、最佳矫正视力(BCVA)、等效屈光度(SE)]水平、角膜高阶像差指标[总高阶像差(HOA)、彗差(Coma)、球差(SA)]水平、散光矫正指标[成功指数(IOS)、变平指数(FI)、矫正指数(CI)]水平和并发症发生率。结果:术后3个月,两组SE水平均高于术前,且观察组高于对照组,差异有统计学意义(P<0.05);两组BCVA、UCVA水平均低于术前,但组间比较,差异无统计学意义(P>0.05);两组HOA、Coma、SA水平均高于术前,但观察组低于对照组,差异有统计学意义(P<0.05);观察组IS、CI水平均低于对照组,FI水平高于对照组,差异有统计学意义(P<0.05);两组均未发生严重并发症。结论:角膜地形图引导的FS-LASIK治疗近视合并散光患者,可提高等效屈光度,改善散光矫正指标水平,降低角膜高阶像差指标水平,效果优于普通FS-LASIK治疗效果。

FS-LASIK Xtra治疗中高度近视患者术后2a的矫正效果

目的:评估FS-LASIK Xtra治疗中高度近视患者术后2 a的矫正效果及角膜形态的稳定性。方法:回顾性病例对照研究。纳入2019-08/2020-08在我院拟行屈光手术的中高度近视合并散光患者30例58眼,根据术前角膜地形图中圆锥角膜筛查相关指数行不同手术方式,分为FS-LASIK Xtra组15例29眼,FS-LASIK组15例29眼。术前,术后3 mo,1、2 a观察裸眼视力(UCVA)、最佳矫正视力(BCVA)、等效球镜度(SE)及Sirius三维角膜地形图仪测量的不同直径区域(3、5、7 mm)前后表面角膜曲率。结果:两组患者术后不同时间点UCVA均较术前明显提高(均P<0.01),两组间UCVA和SE比较均无差异(P>0.05)。术后2 a,FS-LASIK Xtra组25眼(86%),FS-LASIK组24眼(83%)残余散光为-0.25-0 D。两组实际矫正SE与预矫正SE均呈正相关(均P<0.05)。两组患者术后3 mo,1、2 a不同直径区域(3、5、7 mm)前后表面角膜曲率均较术前有差异(均P<0.05),术后1、2 a FS-LASIK Xtra组角膜直径3、5 mm后表面曲率均高于FS-LASIK组(P<0.05)。结论:FS-LASIK Xtra治疗中高度近视患者有良好的安全性、有效性及可预测性。