Visual field analysis after laser in situ keratomileusis

目的 研究准分子激光原位角膜磨镶术(laser in situkemtomileusis,LASIK)对患者视野的影响.方法 用Octo-pusl01全自动视野计G2程序的TOP/BY分程序对LASIK手术的近视患者于术前、术后6个月行视野检查.结果 术后视野的平均敏感度(mean sensitivity,MS)与术前比较,差异无显著性(P＞0.05).术后视野的指数平均缺损(mean defeet,MD)与术前比较,差异有显著性(P＜0.01).手术前、手术后视力与手术前后各自视野MS、MD均无显著相关性(P＞0.05).手术前后MS和MD平均差值与术前屈光度数、角膜切削百分比、激光切削时间、负压吸引时间、瞳孔直径、年龄、性别等行Spearman相关分析显示均无相关性(P＞0.05).结论 手术对视网膜和视神经结构和功能影响还不足以导致临床上明显的功能损伤,没有表现出有临床意义的功能改变.LASIK手术前后视野无明显变化,蓝/黄视野计与标准白色视野计检测的视野结果一致,说明两者检测敏感性相当。

ABSTRACT
 Introductions: Laser in situ Keratomileusis (LASIK) is the most common refractive surgery to treat myopia. One of the most common complain after this procedure is blurry near- vision.
 Objectives: To evaluate the role of accommodation amplitude (AA) in myopic patients before and after LASIK and its effect to blurry near-vision in myopic patients after LASIK
 Methods: Patients with myopia who underwent LASIK procedure in Sriwijaya Eye Center Hospital from January to February 2018 studied prospectively. AA was assessed before and after LASIK with 1 day, 1 week and 1 month. Myopia degree, intraocular pressure (IOP), age, gender, ablation and corneal profile were also assessed.
 Results: A total 52 eyes from 32 patients were included. Visual acuity (VA) of all sample were significantly improve in 1 day after LASIK (p 0,001). Mean AA in myopic patients before LASIK 9,25 D and AA 1 day after LASIK were all significantly decrease into 9,00D (p 0,012) which can cause in blurry near- vision after LASIK. In 1 month followed-up, mean AA is significantly improved into 11,00 D (p 0,000) with no complain. Other factor that affect the changing AA were corneal cell density (CD), IOP and AA before LASIK.
 Conclusions: There is significant AA difference in myopic patients before and after LASIK. Blurry near-vision after LASIK is caused by AA adaptation mechanism after LASIK.

Pupil response to tropicamide following LASIK

Purpose To present a case of late-onset interface fluid syndrome (IFS) and a literature review on this rare clinical entity. Introduction IFS is an uncommon complication of laser in situ keratomileusis (LASIK). Although generally appearing in the early postoperative period, IFS has been reported even years after LASIK. Methods A case report of IFS manifesting 19 years after uneventful LASIK, which prompted a literature search for similar, late-onset cases in MEDLINE PubMed. This article reports on a case of IFS appearing 19 years after LASIK surgery, including extensive patient history and analytical presentation of clinical findings, ancillary testing, and short-term follow-up. Furthermore, a literature search for similar cases was performed on MEDLINE, focusing on the etiology and management of late-onset IFS. Results Through thorough ancillary testing, the interface fluid was attributed to elevated intraocular pressure (IOP) arising from primary open-angle glaucoma. Antiglaucoma drops resulted in complete fluid regression. A narrative review was conducted based on the 29 case reports that were recovered from the literature search. Conclusion IFS represents an uncommon complication that could appear years after LASIK. Careful clinical examination and anterior segment optical coherence tomography promote early diagnosis. Similar cases may manifest due to elevated IOP of variable etiology or as a result of endothelial dysfunction. Depending on the etiology, IOP control or keratoplasty may resolve the condition.

Purpose: To evaluate the changes of anterior corneal aberrations before and after laser in situ keratomileusis (LASIK) and to assess the correlation between contrast sensitivity and anterior corneal aberrations. Methods: Right eyes of 51 patients including 6 males and 45 females undergoing conventional LASIK from September 2000 to July 2003 were enrolled. The calculation of anterior corneal aberrations before and after LASIK was obtained by analyzing the corneal topography from TMS-1 by using VOL-CT Version 6.23 software. Contrast sensitivity was measured after LASIK with an MCT 8000 under daytime and nighttime settings and with glare conditions. The differences of the Zernike coefficients and root mean square (RMS) of anterior corneal aberrations before and after LASIK were analyzed. The changes of contrast sensitivity at 1.5, 3, 6, 12, and 18 cpd were added separately for daytime and nighttime contrast sensitivity with and without glare after LASIK and were correlated with the changes of anterior corneal aberrations. Results: Vertical coma, RMS of coma-like RMS of spherical-like, RMS of trefoil-like and RMS of higher-order anterior corneal aberrations increased significantly after LASIK surgery. There were no significant correlations between the changes of anterior corneal aberrations and the changes of contrast sensitivity at daytime and nighttime, with and without glare. Contrast sensitivity at daytime and nighttime decreased at each spatial frequency after LASIK. Conclusions: LASIK surgery induces changes of the anterior corneal aberrations. However, changes in anterior corneal aberrations did not correlate with the changes of contrast sensitivity at daytime and nighttime, with and without glare.

The purpose of this study was to report a novel clinical entity characterized by bilateral calcium deposits in the flap interface after uncomplicated laser in situ keratomileusis (LASIK). Slit-lamp examination, anterior segment optical coherence tomography imaging, and histopathologic analysis of an interface opacity were performed to characterize and identify the origin of the interface opacities. Two unrelated healthy young men who underwent LASIK in both eyes at 20 (case 1) and 44 (case 2) years of age were diagnosed with bilateral, white anterior stromal opacities 5 years after LASIK surgery. Slit-lamp examination and anterior segment optical coherence tomography imaging demonstrated that the opacities were located at the level of the LASIK interface in both eyes of both cases, with most of the opacities located at the temporal edge of the flap in each eye of case 2. An opacity from case 2 demonstrated birefringence using polarization microscopy and staining with Alizarin red, indicative of calcium deposition. The serum calcium level was borderline elevated in case 1 and within normal limits in case 2. Intrastromal calcium deposition can occur after LASIK surgery, with the deposits resembling dystrophic deposits located in the LASIK flap interface in individuals with granular corneal dystrophy type 2. Because the etiology and management of calcific and dystrophic interface deposition after LASIK are distinct, it is important for clinicians to differentiate the 2 entities based on the examination, diagnostic imaging, and, if necessary, molecular genetic analysis.

Diagnosis of post-LASIK occult Chandler syndrome

Objective To investigate the safety and effectiveness of using laser in situ keratomileusis (LASIK) for the treatment of refractive deterioration after radial keratotomy (RK) surgery.Methods Fifteen patients (28 eyes) in this retrospective study underwent repeat LASIK surgery after they had undergone RK surgery about ten years earlier.The vision of these patients had worsened so they wanted to acquire good vision through repeat LASIK surgery.The Nidek EC-5000 laser treatment system was used for the surgery.Patients were followed up for more than 6 years to monitor the changes in pre- and postoperative visual acuity, complications, corneal prosthetic condition, etc.Results During the 6-year follow-up period, uncorrected visual acuity was better than or equal to preoperative best corrected visual acuity (BCVA) in 26 eyes (93％),but near visual acuity was worse in 25 eyes (89％).Two eyes had low astigmatism (-0.50～-0.75 D) so these patients did not achieve preoperative BCVA.The corneal flap edge healed slowly in 10 eyes and the corneal flap edge had opaque-like lines in 2 eyes.Dry eye was a complication for about 98％ of the patients so eye drops had to be used for a long term.Conclusion LASIK surgery for the treatment of patients with deteriorated vision or low astigmatism after RK surgery is a safe and effective refractive surgery.Patients were satisfied with the treatment but must be informed that they need to be followed up for a long time. Key words: Keratomileusis,laser in situ; Keratotomy,radial; Treatment outcome

Steroid-induced glaucoma after laser in situ keratomileusis associated with interface fluid

The corneal asphericity refers to most normal corneal surface is an aspherical flat oval, which is helpful to improve the visual quality.In most cases, corneal aspherical coefficient Q-value is negative, and different normal Q-value is reported in literatures, corneal Q-value is influenced by many factors, quadrants have great effects on it, the influence of age is weak, there are correlation between myopic degree, ocular axial length, radius of curvature, intraocular pressure and Q-value.The corneal refractive surgery is one of the most important methods to correct refractive errors, but it has negative effects on the corneal asphericity, and then results in glare, visual quality degradation and other issues.Different corneal refractive surgeries would have different effects on the corneal asphericity.Wavefront aberration-guided femtosecond laser in situ keratomileusis（LASIK) surgery and Q-value guide LASIK are superior to standardized LASIK, the change of Q-value after femtosecond lenticule extraction（FLEx) surgery is less than that after wavefront aberration guided LASIK.The influence of femtosecond laser in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE) on Q-value are rarely reported.In addition, the Q-value changes from negative to positive after corneal refractive surgery of myopia, the variation tendency is opposite after hyperopia surgery.Q-value variation is highly correlated to spherical equivalent, the impact of laser and healing still needs further exploration.In order to further exploring of the corneal asphericity and getting a better effect of surgery, here is a review about normal corneal asphericity and the effects of the corneal refractive surgery on it. Key words: Cornea; Asphericity; Q-value; Refractive surgery

Keratocyte density of central human cornea after laser in situ keratomileusis

PurposeTo compare the incidence of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK) with flap creation using the Femto LDV and IntraLase™ FS60 femtosecond lasers.0MethodsA total of 818 consecutive myopic eyes had LASIK performed using either Femto LDV or IntraLase FS60 for flap creation. The same excimer laser, the Allegretto Wave® Eye-Q Laser, was used for correcting refractive errors for all patients. In the preoperative examination, uncorrected distance visual acuity, corrected distance visual acuity, and manifest refraction spherical equivalent were measured. At the postop examination, the same examinations were performed along with a slit-lamp biomicroscopic examination, and patients with DLK were classified into stages. For the statistical analysis of the DLK occurrence rate and the visual and refractive outcomes, the Mann-Whitney’s U-test was used.ResultsIn the Femto LDV group with 514 eyes, 42 (8.17%) had DLK. In the IntraLase FS60 group with 304 eyes, 114 (37.5%) had DLK. There was a statistically significant difference in the DLK incidence rate between these groups (P < 0.0001). Both groups had excellent visual and refractive outcomes. Although low levels of DLK were observed for both groups, they did not affect visual acuity.ConclusionWhile there were significantly fewer incidences of low level DLK when using Femto LDV, neither femtosecond laser induced high levels of DLK, and any postoperative DLK cleared up within 1 week. Therefore, both lasers provide excellent results, with no clinical differences, and both excel at flap creation for LASIK.

To compare, in the same individuals, the safety and efficacy of laser in situ keratomileusis (LASIK) in eyes with and without previous retinal detachment surgery. In a prospective clinical trial, seven myopic patients who had previously undergone scleral buckling surgery in one eye underwent conventional LASIK surgery in both eyes. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refraction, Orbscan topography and pachymetry were recorded before and 1, 3, 6 and 12 months after surgery. The eyes were divided into two groups: group 1 consisted of eyes that had undergone previous surgery for retinal detachment, and group 2 consisted of the fellow eyes of the same patients, which had not undergone any previous ocular surgery. Student's t-test for match-paired data was used to evaluate the significance of differences. LASIK was performed successfully in all patients. The UCVA improved in all eyes in both groups. The mean change in the spherical equivalent between 1 and 12 months after LASIK surgery was 1.7 +/- 1.1 and 0.6 +/- 0.5 diopter in groups 1 and 2, respectively (p = 0.019). LASIK may be considered for treatment of myopia in eyes that have had previous surgery for retinal detachment. However, the risk of regression may be higher in such eyes than in eyes with no previous scleral buckling surgery.

To determine the safety and efficacy of performing photorefractive keratectomy (PRK) in corneas previously treated with laser in situ keratomileusis (LASIK) surgery. Fifteen eyes of 14 patients who had initially received LASIK for the treatment of myopia and compound myopic astigmatism were evaluated. Variables included existence of and/or type of flap complication associated with the original LASIK procedure, refractions before and after (3 and 6 months) PRK, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and the development of complications after PRK such as haze, scarring, double vision, or ghosting. All 15 eyes were available for analysis at 6 months. Eleven eyes had experienced flap complications during the initial LASIK procedure and 4 eyes had experienced complications in the LASIK postoperative period. Characteristics prior to performing PRK included 11 myopic and 4 hyperopic eyes. By 6 months after PRK treatment, 87% of eyes had UCVA > or = 20/40, 53% had > or = 20/25, and 40% had > or = 20/20. All eyes had BSCVA of > or = 20/30, with 73% being > or = 20/20. No eye had lost 2 lines of BSCVA and only 1 eye lost 1 line of BSCVA. Sixty percent of eyes were within 1.0 diopters (D) of emmetropia, and 40% were within 0.5 D of emmetropia. A trend towards undercorrection and surgical induction of astigmatism as confirmed by vector analysis was noted. No eye developed significant haze or scarring. Photorefractive keratectomy may be a safe procedure to perform in corneas previously treated with LASIK surgery. Results show good reduction of refractive error and improvement of UCVA and BSCVA. A significant undercorrection of astigmatism was attributed to surgically induced astigmatism. Further studies are necessary to determine the long-term safety and stability of outcomes.

Role of instrument cleaning and maintenance in the development of diffuse lamellar keratitis