Long term results of no- alcohol laser epithelial keratomileusis and photorefractive keratectomy for myopia

AIM: To evaluate the long term clinical results of mechanical no-alcohol-assisted laser epithelial keratomileusis(LASEK) versus standard photorefractive keratectomy(PRK) for low-moderate myopia.METHODS: Twenty-five eyes treated with LASEK and twenty-five eyes treated with PRK were evaluated with a mean follow-up duration of 60 mo. Mechanical separation of the epithelium was performed with blunt spatula and without application of alcohol. Laser ablation was performed with the MEL-70 excimer laser. All patients were examined daily until epithelial closure; at 1, 3, 6,and 12 mo, and every year subsequently. Main outcome measures were uncorrected distance visual acuity(UDVA), corrected distance visual acuity(CDVA),manifest refraction, haze, efficacy and safety indexes.RESULTS: Twenty-one eyes and 22 eyes completed follow-up of 60 mo in LASEK and PRK group respectively. Manifest refraction at 60 mo follow-up was-0.01 and 0.26 in LASEK and PRK group respectively. In the LASEK group mean UDVA and mean CDVA after60 mo were 20/22 and 20/20 respectively(P 】0.01). In the PRK group mean UDVA and mean CDVA at 60 mo follow-up were 20/20 and 20/20 after 60mo(P 】0.01). The efficacy indexes were 0.87 and 0.95, and the safety indexes were1.25 and 1.4 respectively for LASEK group and PRK group.CONCLUSION: Both standard PRK and no-alcohol LASEK offer safe and effective correction of low-moderate myopia in the long term without any statistically significant difference between the two groups.

Clinical outcomes of transepithelial photorefractive keratectomy versus femtosecond laser assisted keratomileusis for correction of high myopia in South Egyptian population

AIM: To evaluate the safety and efficacy of transepithelial photorefractive keratectomy(t-PRK) with adjuvant mitomycin C(MMC) versus femtosecond laser assisted keratomileusis(Femto-LASIK) in correction of high myopia.METHODS: Prospective randomized comparative study including 156 eyes of 156 patients with high myopia and a spherical equivalent refraction(SER) <-6.00 D. They were divided randomly into two groups: Group A included 72 eyes treated with t-PRK with adjuvant MMC and Group B included 84 eyes treated with Femto-LASIK. Visual acuity, SER, corneal topography, pachymetry and keratometry were assessed for 12 mo postoperatively.RESULTS: The preoperative mean SER was-8.86±1.81 and-9.25±1.70 D in t-PRK MMC group and Femto-LASIK respectively(P=0.99) which improved to-0.65±0.43 D and-0.69±0.50 D at 12 mo follow up. Mean SER remained stable during the 12 mo of follow-up, with no statistically significant difference between the two groups(P=0.64). In t-PRK MMC group, only six eyes needed retreatment after six months of follow up. And two eyes showed haze(one reversible haze grade 2, while the other had dense irreversible haze grade 4).CONCLUSION: t-PRK MMC provides safe and satisfactory visual outcomes and acceptable risk as Femto-LASIK in patients with high myopia.

Single-step transepithelial photorefractive keratectomy in high myopia：qualitative and quantitative visual functions

AIM：To investigate quantitative and qualitative optical outcomes of single-step transepithelial photorefractive keratectomy（Trans PRK）in high myopia.METHODS：In a prospective interventional case-series,30 eyes with high myopia（-6.00 to-8.75 D）with（up to-3.00 D）or without astigmatism were enrolled from Bina Eye Hospital,Tehran,Iran. One-step Trans PRK was performed with aberration-free aspherical optimized profile and SCHWIND AMARIS 500 laser. One-year follow-up results for refraction,visual acuities,vector analysis,ocular wavefront（OWF）and corneal wave-front（CWF）higher order aberrations（HOA）,contrast sensitivity（CS）,and postoperative haze were assessed.RESULTS：After the surgery,both photopic and mesopic CSs significantly improved（both P〈0.001）. We detected significant induction of OWF coma and trefoil（P〈0.001 for both）HOAs; CWF coma（P=0.002）,spherical（P〈0.001）,and tetrafoil（P=0.003）HOAs in 6 mm analysis diameter; and CWF trefoil（P=0.04）HOA in 4 mm analysis diameter. The range of mean induction observed for various HOAs was0.005-0.11 μm. The 86.7% of eyes reached an uncorrected distance visual acuity of 20/20 or better; 96.7% of eyes were within ±0.5 D of targeted spherical refraction. In vector analysis,mean correction index value was 1.03 and mean index of success was 0.22. By 12mo after the operation,no eye lost any number of corrected distancevisual acuity lines. We detected no corneal haze greater than 1~＋ throughout the follow-up.CONCLUSION：Our findings show promising effects of single-step Trans PRK on quality of vision in high myopic eyes. It also improves refraction and visual acuity.

Preliminary results of a new intrastromal corneal ring segment as a tissue saving procedure in photorefractive keratectomy to correct moderate to high myopia

AIM:To evaluate the clinical results after implantation of a new intrastromal corneal ring segment(ICRS)associated with photorefractive keratectomy(PRK)to correct high myopia(HM)patients with thin corneas.METHODS:We evaluated 42 eyes of 23 HM patients that had ICRS implantation followed by PRK.The mean age of patients was 29.1±7.12 y(range 18 to 40 years old).Uncorrected visual acuity(UCVA),best corrected visual acuity(BCVA),keratometry,spherical equivalent,pachymetry,and aberrometry were compared using ANOVA with repeated measurements evaluated preoperatively and at last follow-up visit after the procedures.The refractive predictability and simulated/real corneal ablation were also assessed.RESULTS:The mean follow-up time after PRK was 6.8±1.6 mo.The mean preoperative UCVA improved from 20/800 preoperative to 20/100 after ICRS and 20/35 after PRK.The mean preoperative BCVA was 20/25(range from 20/30 to 20/20)and remained unchanged after ICRS implantation.Following the PRK the mean BCVA was 20/25(range from 20/30 to 20/20).The mean spherical equivalent decreased from-7.25±1.12(range-5.00 to-9.00)preoperatively to-3.32±1.0(range-2.00 to-5.00)postoperatively(P<0.001)after ICRS implantation and decreased from-2.44±1.51 preoperatively to 0.32±0.45(range-0.625 to 0.875)postoperatively(P<0.001)after PRK.The change in BCVA and topographic astigmatism was statistically significant(P<0.0001).CONCLUSION:ICRS in HM associated with PRK can be a tissue saving procedure and an alternative surgical option for correction of moderate to high myopia.

CLINICAL ANALYSIS OF EXCIMER LASER PHOTOREFRACTIVE KERATECTOMY FOR TREATMENT OF MYOPIA AND MYOPIC ASTIGMATISM

To evaluate the efficacy and accuracy of photorefractive keratectomy (PRK) for myopia and myopic astigmatism .SVS APEX excimer laser with a wave length of 193 nm(Sumit Technology Inc. Waltham, Mass, USA) was applied. 316 myopic eyes of 168 patients were treated with PRK between September, 1996 and October, 1997, and 260 eyes (84%) of 150 patients were followed for more than three months, including male 68(116 eyes, 401%) and female 82(144 eyes, 599%). The preoperative spherical equivalent refractive errors ranged from -125D to -1000 (mean -467163D), and astigmatism ranged from 0 to -200D (means -033045D). We divided the patients into two groups according to the referaction: group A (from -125D to -590D) and group B(from -600 to -1000D). The number of eyes in the two groups were 220 and 40 respectively. In group A, on the 10th day, 689% has the uncorrected visual acuity (UCVA) equal to or one line better or lower than the preoperative best corrected visual acuity (BCVA). In 1,3,6 and 12 months, 90 %, 96%, 95% and 94% had the UCVA equal to or one line better or lower than the preoperative BCVA respectively. In group B, on the 10 th day, in 1,3,6 and 12 months, UCVA equal to or one line better or lower than the preoperative BCVA occurred in 359%, 83%, 87%, 86%, and 84% of the cases respectively. Most of the haze showed 051 grades except 3 eyes with the haze of 2 grade in 3 or 6 months and it changed to 1 and 05 grade respectively within one year. In 10 days and 1,3,6,12 months postoperatively, the corneal haze was noted in 329%, 848%, 628%,90% and 28% of the treated eyes respectively. We found that 193 nm excimer laser PRK was a predictable, safe, stable, and effective refractive surgery for correcting myopia up to -1000D in Chinese patients, and the effect was better in myopia lower than -600D.

Factors affecting single-step transepithelial photorefractive keratectomy outcome in the treatment of mild,moderate,and high myopia:a cohort study

AIM:To investigate the effect of preoperative factors on visual acuity,higher-order aberrations(HOAs),and index of success for spherical change(S.IOS)after transepithelial photorefractive keratectomy(t-PRK)for treating different grades of myopia.METHODS:This was a retrospective one-armed cohort study where patients with high,moderate,or mild myopia treated with single-step t-PRK using Amaris 500 Hz excimer laser were evaluated for visual acuity,refractive status,corneal topography,HOAs,S.IOS,and mean efficiency and safety index before and 6 mo after surgery.RESULTS:A total of 154 eyes of 77 patients with mild(n=59),moderate(n=83),and high(n=12)myopia were reviewed.The efficiency and safety indices for vision recovery by single-step t-PRK were 98%and 100%,respectively.The achieved spherical equivalent(SE)was within 1 diopter(D)in 151(98%)eyes.The median of the S.IOS was 1.18[interquartile range(IQR)1.0,1.4].The change in S.IOS was significantly correlated with age(P=0.007),6.5 mm ablation zone(Mann-Whitney U test,P<0.01),and mild and moderate grade of myopia(Kruskal–Wallis test,P<0.001).Trefoil aberration,spherical aberration,and aberration coefficient types of HOA increased significantly(Wilcoxon test,P<0.001)6 mo post-surgery.There was a significant correlation between spherical aberration and aberration coefficient HOAs by myopia grades(P<0.05).CONCLUSION:Single-step t-PRK has promising short-term outcomes for refractive corrections and vision improvement to treat all three grades of myopia.

A 3-month comparison study of subjective and objective visual quality of small incision lenticule extraction and transepithelial photorefractive keratectomy in patients with low and moderate myopia

AIM:To compare the subjective and objective visual quality between small incision lenticule extraction(SMILE)and transepithelial photorefractive keratectomy(t PRK)in patients with low and moderate myopia.METHODS:Patients undertaking SMILE or t PRK for the correction of low and moderate myopia were consecutively recruited in this prospective cohort study with a 3-month follow-up period.Objective evaluation[visual acuity test,manifest refraction,wavefront aberrations,the total cut-off value of the total modulation transfer function(MTFcut-off),and Strehl ratio(SR)]and subjective evaluation of visual quality(quality-of-life questionnaire)were conducted before surgery and at days 1,7,30,and 90 after surgery.RESULTS:A total of 47 patients(94 eyes)with SMILE and 22 patients(22 eyes)with t PRK were enrolled.The uncorrected visual acuity(UCVA)was better in SMILE patients on day 7 after surgery(1.13±0.13 vs 0.99±0.17,t=4.85,P<0.001)but was comparable at days 30 and 90.At day 90,the SMILE group had a lower spherical equivalent(SE)than the t PRK group(0.04±0.31 vs 0.19±0.43,t=2.08,P=0.042).Total higher order aberrations(HOAs)were induced in both surgical types,which were more evident in the t PRK group with 3-mm pupil diameter(0.16±0.07 vs0.11±0.05,t=4.27,P<0.001)and 5-mm pupil diameter(0.39±0.17 vs 0.36±0.11,t=2.33,P=0.022).The MTFcut-offand SR showed a trend of improvement in both SMILE and t PRK patients but were statistically better in the SMILE group with both pupil diameters.There was a significant improvement of contrast sensitivity(CS)over baseline levels at the spatial frequency of 18 cycles/degree(c/d)in the SMILE group(F=2.72,P=0.033)and at 3 c/d(F=3.03,P=0.031),12 c/d(F=3.72,P=0.013),and 18 c/d(F=4.62,P=0.004)in the t PRK group.The subjective quality of life questionnaire showed a steady improvement in the SMILE group(F=8.31,P<0.001)but not the t PRK group.CONCLUSION:SMILE and t PRK are both safe and effective ways to correct low and moderate myopia.A generally better and quicker recovery of visual quality favors the application of SMILE in qualified patients.

Phototherapeutic Keratectomy Combined with Photorefractive Keratecto-my for Treatment of Myopia with Corneal Scars

To evaluate the effect of phototherapeutic keratectomy combined with photorefractive ker- atectomy in the treatment of myopia with corneal scars, corneal epithelium was removed with laser plus scraping. Corneal scars were removed with PTK, followed by PRK for myopia. Healon was used to make corneal surface smoother during operation. 30 eyes of 24 cases of myopia with corneal scars were followed up for one year. Mean corrected vision was 0. 51 and myopic degree was -6. 42D ±4. 26D before operation. After operation, corneal scars of 21 eyes (70. 0%) were removed in oper- ative zone. The vision of 27 operated eyes (90. 0%) was equal to or better than best corrected vi- sion. Mean postoperative visual acuity was 0. 72. Corneal surface was smoother and astigmatism was reduced after the surgery. Our study showed that PTK combined with PRK is a safe and effective treatment for myopia with corneal scars.

Transepithelial photorefractive keratectomy mode using SCHWIND-ESIRIS excimer laser:initial clinical results

AIM: To evaluate postoperative pain, uncorrected visual acuity (UCVA), and cornea haze value after transepithelial photorefractive keratectomy (T-PRK) performed with aspherical ablation profile using SCHWIND ESIRIS excimer laser. METHODS: Retrospective case series. Fifty-nine eyes (32 patients) with myopia associated with or without astigmatism underwent phototherapeutic keratectomy (PTK) followed by photorefractive keratectomy (PRK) which performed by Optimized Refractive Keratecomy (ORK)-CAM software based on aspherical ablation profile using SCHWIND ESIRIS excimer laser. Postoperative pain scale was measured on a questionnaire through five levels. Haze was graded by five grades, and UCVA, manifest refraction spherical equivalent (MRSE) were analyzed. RESULTS: Mean pain level was (1.37 +/- 0.613) (range: 1 to 3), the mean time picking out the soft contact lens was (6.22 +/- 1.73) days, at 3 months, UCVA was 1.0 for 40 eyes (67.8%), 0.5 for all eyes (100.0%). The UCVA was significantly less than the preoperative best spectacle corrected visual acuity (BSCVA) (t=-2.84, P=0.006), haze value was (0.27 +/- 0.25), no patients had a haze grade up to 2. Mean MRSE was (0.76 +/- 0.96) diopter(D) by 3 months. CONCLUSION: The outcomes from this study show that using the SCHWIND ESIRIS aspherical ablation profile for transepithelial PRK has a good visual result. The primary advantage is related to a spherical ablation profile, automatically considers the ablation volume of the stroma and the accurate and smooth removal of the epithelium with PTK. Additional studies are needed to determine long-term outcomes.

Photorefractive keratectomy after cataract surgery in uncommon cases: long-term results

AIM： To evaluate the efficacy and safety of the excimer laser correction of the residual refractive errors after cataract extraction with intraocular lens（IOL） implantation in uncommon cases.METHODS： Totally 24 patients with high residual refractive error after cataract surgery with IOL implantation were examined. Twenty-two patients had a history of phacoemulsification and IOL implantation, and two had extra-capsular cataract extraction with IOL implantation. Detailed examination of preoperative medical records was done to explain the origin of the post-cataract refractive errors. All patients underwent photorefractire keratectomy（PRK） enhancement. The mean outcome measures were refraction, uncorretted visual acuity（UCVA）, best corrected visual acuity（BCVA） and corneal transparency and follow up ranged from 1 to 8 y.RESULTS： The principal causes of residual ametropia was inexact IOL calculation in abnormal eyes with high myopia and congenital lens abnormalities, followed by corneal astigmatism both suture induced and preexisting. After cataract surgery and before the laser enhancement the mean spherical equivalent（SE） was-0.56±3 D ranging from-4.62 to ＋2.25 D in high myopic patients, instead it was-1±1.73 D ranging from-3.25 to ＋3.75 D in the astigmatic eyes, with a mean cylinder of-3.75±0 ranging from-3 to ＋5.50 D. After laser refractive surgery the mean SE was 0.1±0.73, ranging from-0.50 to ＋1.50 in the myopic group, and it was-0.50±0.57 ranging from-1.25 to ＋0.50 in astigmatic patients, with a mean cylinder of-0.25±0.75. In myopic patients the mean UCVA and BCVA were 0.038±0.072 logMAR and 0.018±0.04 respectively, both ranging from 0.10 to 0.0. In astigmatic patients, the mean UCVA and BCVA were 0.213±0.132 and 0.00±0.0 respectively, UCVA ranging from 0.50 to 0.22 and BCVA was 0.00. All patients presented normal corneal transparency. No ocular hypertension was detected and no corneal haze was observed. All registered values remained stable also at the end line evaluation.CONCLUSION： The excimer laser treatment of residual refractive errors after cataract surgery with IOL implantation in abnormal eyes resulted in satisfactory and stable visual outcome with good safety and efficacy.

Transpalpebral intraocular pressure measurement by Diaton compared to Goldman applanation tonometer in myopic eyes before and after transepithelial photorefractive keratectomy in Saudi Arabia

AIM:To compare intraocular pressure(IOP)measured via the trans palpebral IOP(tp IOP)method using a Diaton or with a Goldman applanation tonometer(GAT)and study the determinants of IOP difference in eyes undergoing transepithelial photorefractive keratectomy(TPRK)for myopia.METHODS:This cross-sectional validation study was held in 2020 in an eye hospital in Saudi Arabia.IOP was measured by Diaton and GAT before treatment,after one week,and one month of TPRK.It is considered if IOP difference by Diaton and GAT was less than±2 mm Hg acceptable.The IOP difference was tested if correlated to spherical equivalent(SE),central corneal thickness(CCT),age,gender,or tp IOP.RESULTS:Totolly 200 myopic eyes of 100 patients were included in the study.The mean difference of IOP measured by two methods before TPRK,1wk,and 1mo after TPRK were 0.790,-0.790,and-0.920 mm Hg,respectively(P<0.001).Diaton could measure IOP effectively 89.5%eyes before TPRK and 82%and 84%at 1wk and 1mo after TPTK,respectively.At week 1,IOP differences were significantly correlated to baseline CCT(P=0.02)and tp IOP at week 1(P<0.001).One month after TPRK,only tp IOP was significantly correlated to the difference in IOP(P<0.001).CONCLUSION:Diaton is a good screening tool for IOP before TPRK.It helps in monitoring IOP after surgery.Although more practical,it is less efficient than GAT.In eyes with high myopia and low tp IOP before surgery,IOP post-TPRK by Diaton and GAT could differ.

Comparison of laser epithelial keratomileusis and photorefractive keratectomy for the correction of myopia： a meta-analysis

Background It is unclear whether a laser epithelial keratomileusis （LASEK） has any significant advantage over a photorefractive keratectomy （PRK） for correcting myopia. We undertook this meta-analysis of randomized controlled trials to examine possible differences in efficacy, accuracy, safety and side-effects between two methods, LASEK and PRK, for correcting myopia. Methods A systematic literature retrieval was conducted in the PubMed, EMBASE, Chinese Bio-medicine Database, and Cochrane Controlled Trials Register to identify potentially relevant randomized controlled trials. The statistical analysis was performed using a RevMan 4.2 software. The results included efficacy outcomes （proportion of eyes with uncorrected visual acuity （UCVA）〉 20/20 at 1 month and 12 months post-treatment）, accuracy outcomes （proportion of eyes within ±0.50 diopters （D） of target refraction at 1 month and 12 months post-treatment）, safety outcomes （loss of 〉2 lines of best spectacle-corrected visual acuity （BSCVA） at 〉 6 months post-treatment）, mean pain scores on day 1 post-treatment, and mean corneal haze scores at 6 and 12 months post-treatment. Results Seven articles describing a total of 604 eyes with myopia from 0 to -9.0 D were identified in this meta-analysis. The combined results showed that the efficacy and accuracy outcomes between the two groups at 1 month and 12 months post-treatment were comparable. No patient lost 〉 2 lines of BSCVA at 〉 6 months post-treatment in four relevant trials. Compared with PRK, LASEK did not relieve discomfort on day 1 post-treatment or reduce corneal haze intensity at 6 and 12 months post-treatment. Conclusions According to the available data, LASEK does not appear to have any advantage over PRK for correcting myopia from 0 to -9.0 D. This meta-analysis focuses mainly on the comparison of the early, mid-term and mid-long term results of the two methods. Additional studies to compare the long-term （〉one year） results should be considered.

EXCIMER LASER PHOTOREFRACTIVE KERATECTOMY FOR MYOPIA IN CHINA A REPORT OF 750 EYES WITH A 6-MONTH FOLLOW-UP

A total of 750 six-month follow-up records of myopia treated with excimer laser photorefractive keratectomy (PRK) were analyzed. By 6 months, in group 1 (up to-6.00D, 587 eyes), uncorrected visual acuity was improved to 20 / 20 or better in 86.7% of treated eyes and 95.4% fell into the range of refraction of±1.00D. In group 2 (-6.25D to -11.00D, 163 eyes), 74.5% of treated eyes had uncorrected visual acuity of 20 / 20 or better and 89.4% of the eyes were within ±1.00D. The designed predictability of the two groups was the same (P>0.1). The refractive stability from 3 to 6 months between the two groups was not statistically different, and no severe complications were observed in these two groups. The excimer laser PRK for correcting myopia up to -11.00D appears to be effective, predictable, stable and safe in this study. The ideal outcome may result from the precise ablation quality of excimer laser, its computerized surgical manipulation and an appropriate postoperative management including detection of refractive indices by conical topography and modulation by steroid.

Relationship between Corneal Thickness,Corneal Curvature,and Intraocular Pressure before and after Laser Treatment for Simple Myopia

Purpose:.To determine the relationship of central corneal thickness(CCT), curvature(CC), and intraocular pressure(IOP) as determinative factors for corneal biomechanics and in refractive surgery.Methods:.The study investigated 48 eyes from subjects who visited the Excimer Laser Surgery Clinic at the Department of Ophthalmology. The refractive error, IOP, CCT, and CC were measured in all participants. After 3 months, all examinations were repeated.Results:.Linear regression demonstrated a significant positive relationship between pre- and postoperative CCT,.CC,.and IOP values..The IOP showed a significant correlation with CCT(P=0.033) for pre-PRK, but no significant relationship was seen post-PRK. The CCT also correlated significantly with CC both pre- and post-PRK(P<0.05).Conclusion:.The IOP was significantly correlated with CCT before PRK, but its behavior differed after surgery. Nearly the same correlation was seen between CCT and CC before and after the PRK;.nevertheless,.IOP measurements should be calculated or estimated more precisely after PRK based on CCT corrections.

Efficacy of ICL combined with Trans-PRK on corneal endothelial cell density in patients with high myopia

Objective:To explore the efficacy of implantable collamer lense (ICL) combined with laser keratectomy via corneal epithelium Trans-PRK in the treatment of patients with high myopia and its effect on corneal endothelial cell density.Methods: A prospective analysis was performed on patients with ultra-high myopia admitted to the department of ophthalmology of our hospital from March 2014 to March 2017. Six months after ICL implantation, the patients still had myopia and received Trans PRK treatment again. The number of cases was 30 and 52 eyes. Patients were followed up postoperatively. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), dioptre (D), intraocular pressure, ICL arch height, anterior chamber volume, anterior chamber depth, and changes in corneal endothelial cell counts were observed preoperatively, 6 months after ICL implantation and 6 months after Trans PRK so as to assess the effectiveness and safety of the surgery.Results: UCVA and BCVA of the eyes were significantly higher 6 months after ICL implantation and 6 months after Trans-PRK than those before the surgery, and UCVA of the eyes 6 months after Trans-PRK was significantly higher than that 6 months after ICL implantation. There was no increase in intraocular pressure in all patients after surgery. There was no significant difference in intraocular pressure preoperatively, 6 months after ICL implantation and 6 months after Trans PRK. The ICL arch height of the eyes 6 months after Trans-PRK was slightly lower than that 6 months after ICL implantation, but the difference was not statistically significant. Both anterior chamber volume and anterior chamber depth were significantly lower 6 months after ICL implantation and 6 months after Trans PRK than whose before the surgery, and anterior chamber depth 6 months after Trans PRK was significantly lower than that 6 months after ICL implantation. The number of corneal endothelial cells 6 months after ICL implantation was slightly less than that before surgery, but it was not statistically significant. The number of corneal endothelial cells 6 months after Trans PRK was higher than that 6 months after ICL implantation and close to the preoperative level.Conclusion: Trans PRK can effectively improve the eye diopter of patients with high myopia and residual myopia after ICL implantation. It has little effect on the density of corneal endothelial cells, can significantly improve visual acuity, and achieve the expected operation effect with safe operation, which is worthy of clinical promotion.

准分子激光屈光性角膜切削术矫治近视术后角膜上皮的重塑及相关因素分析

背景准分子激光角膜屈光手术矫治近视后角膜上皮会发生重塑效应，主要表现为上皮厚度的变化，目前关于单一步骤的经角膜上皮的准分子激光屈光性角膜切削术（TransPRK）后角膜上皮厚度变化的研究鲜见报道。目的探讨TransPRK矫治近视术后角膜光学区内不同区域上皮厚度的变化及其相关影响因素。方法采用回顾性研究设计，收集2014年8月至2015年6月在济南市明水眼科医院行TransPRK手术的近视及近视散光患者43例43眼，术前等效球镜度为一1．25- -6．25D。分别于术前及术后1周、1个月、3个月及6个月应用频域眼前节光相干断层扫描仪（OCT）对患者角膜0～2、2～5及5～6mm范围内的上皮厚度进行测量，研究术后不同时间角膜上皮厚度的变化规律并分析其与屈光度、切削深度、光学区大小以及角膜非球面性变化（Q值）等因素的相关性。结果术前及术后1周、1个月、3个月及6个月角膜中央上皮厚度分别为（52．37±3．42）、（53．97±4．33）、（51．03±4．11）、（55．14±5．46）和（56．68±5．09）p,m，术后3个月与6个月角膜上皮厚度与术前比较差异均有统计学意义（均P〈0．05）。术后6个月，角膜0～2、2～5及5～6mm范围内角膜上皮厚度较术前分别增厚（3．69±4．23）、（5．19±3．88）和（6．23±3．91）txm，与术前比较差异均有统计学意义（均P〈0．01）；角膜上皮厚度与屈光度和Q值变化量均呈正相关，与光学区大小呈负相关（均P〈0．05）；2-5mm区和5～6mm区上皮厚度变化与切削深度均呈正相关（r=0．380、0．383，均P〈O．05），而中央区角膜上皮厚度与切削深度无相关性（P〉0．05）。结论TransPRK术后角膜光学区内上皮增厚的分布呈“负透镜式”的变化，越接近光学区周边增厚越显著，上皮厚度变化量受屈光度、切削区大小及切削深度的影响，且这种不均匀增厚会影响角膜的非球面特性，可能会在一定程度上掩藏个性化手术应该达到的效果。

准分子激光屈光性角膜切削术后高透氧性角膜接触镜的应用

目的:探讨高透氧性角膜接触镜对准分子激光屈光性角膜切削术(photorefractive keratectomy,PRK)后眼刺激症状及角膜上皮愈合的影响。方法:共95例190眼PRK病例,术后随机选择一只眼戴软性亲水性高透氧的角膜接触镜,另一只眼配戴普通月抛型角膜接触镜。术后记录术眼自觉症状,观察角膜上皮愈合情况,检查术后6mo裸眼视力,同时进行haze评分。结果:高透氧角膜接触镜组术眼视物模糊、眼痛、畏光均轻于普通月抛型角膜接触镜组,两组比较差异有统计学意义(P<0.05)。高透氧角膜接触镜组平均角膜上皮愈合时间分别为3.11±2.12d,普通月抛型角膜接触镜组为4.02±2.21d,两组比较差异有统计学意义(P<0.05)。角膜上皮72h内愈合者高透氧角膜接触镜组占46%,普通月抛型角膜接触镜组占36%。术后第7d裸眼视力高于1.0者高透氧角膜接触镜组为60眼(63%),普通月抛型角膜接触镜组为48眼(51%)。术后6mo两组术后裸眼视力无显著性差异(P=0.35),两组haze发生率比较无显著性差异(P=0.55)。结论:PRK术后使用高透氧性角膜接触镜可以明显减轻术后患者的角膜刺激症状,减少患者的术后不适感,缩短角膜上皮的愈合时间。

激光角膜切削术后皮质类固醇性高眼压

为防止准分子激光角膜切削术后近视度数回退，术后局部滴强地松龙６个月。经对皮质类固醇性高眼压和青光眼进行了分析结果表明，１６２８只术眼皮质类固醇性高眼压（≥２．９３３ｋＰａ）术后１个月和３个月的发生率分别为９．８９％和１５．０５％，３月高眼压的发生率高于１月高眼压的发生率，差异有显著性；男性患者激素升压反应比女性患者明显，１个月时分别为１６．６４％和５．５４％；３个月时分别为１８．０５％和１３．１２％；高眼压的发生与原屈光状态（≤－２．９０Ｄ和≥－３．００Ｄ）无关。皮质类固醇性青光眼５例（０．３０％）。同时对准分子激光角膜切削术后皮质类固醇性高眼压的防治进行了讨论。

家兔角膜准分子激光切削术后病理学观察

目的对近期准分子激光角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ，ＰＲＫ）后角膜伤口变化进行组织病理学观察。方法应用１９３μｍ扫描式准分子激光对８只实验兔眼行光学角膜切削术并于术后２月时组织病理学检查。结果切削区角膜表面光滑，均匀一致，上皮轻度增厚；基底膜再生，但呈厚薄不一、不连续等不成熟表现，上皮和实质层仍存在散在裂隙；基质处大部分新生胶原纤维排列有序，但局部浅实质层可见角膜细胞增多等瘢痕样改变。结论兔眼ＰＲＫ术后２月显示，组织结构基本正常，但仍存有组织薄弱处和特殊性改变。强调半桥粒－基底膜复合体在ＰＲＫ上皮修复中的意义。

三种准分子激光角膜切削术后中央角膜厚度变化的对比研究

目的比较三种准分子激光角膜切削术后中央角膜厚度(CCT)的差异并探讨不同手术方式角膜切削量的设定。方法使用Pentacam三维眼前段分析仪测量行SBK、LASIK、Epi-LASIK术的近视患者共136例266只眼术前术后的CCT,按屈光度分为低、中、高三组,分别计算和比较CCT及实际切削深度和设计切削深度的差值(Diff值)。结果Epi-LASIK患者低、中、高度组术前CCT分别为(495.70±24.94)、(501.57±31.34)和(525.18±16.53)μm,较SBK和LASIK组患者CCT明显偏薄(P<0.01),SBK与LASIK患者术前术后的CCT无显著性差异。SBK、LASIK术后Diff值比较:低度组Diff值分别为(6.57±12.72)、(5.33±9.51)μm;中度组Diff值分别为(7.07±18.19)、(4.42±8.72)μm;高度组分别为Diff值(11.52±10.29)、(7.00±7.33)μm,各组比较差异均无显著性意义。三种手术方式的实际切削的角膜深度均大于设计量。结论CCT较薄的患者多选择Epi-LASIK。充分估计术中实际切削深度与设计切削深度存在的差异是提高手术安全性的保障。