bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correction of Myopia With Er:YAG Laser Fundamental Mode Photorefractive Keratectomy
Authors: Jean Benedikt , Kriegerowski Martin , Matallana Michael , Bende Thomas 
Published: April 2021

ABSTRACT
BACKGROUND: Photorefractive keratectomy (PRK) has been performed with the ultraviolet 193 run radiation of the excimer laser. Due to its high absorption in water (3 µm water absorption band), the Er:YAG's 2.94 µm wavelength in the mid-infrared also qualifies for photoablation.
METHODS: A new laser source, providing an output energy of 2.6 J (multimode) and 380 mJ in the fundamental mode, was used to perform corneal areal ablation (large) in two blind human eyes eccentrically. The fundamental mode provided a Gaussian-shaped beam profile, able to ablate more tissue centrally, depending on the fluence applied.
RESULTS: The visible ablation diameter (opaque area) at the corneal surface was about 5 mm. Its effective ablation diameter was 4.85 ± 0.2 mm. The maximal ablation depth was 155 ± 5 µm. Surface roughness was 0.73 ± 0.06 µm, as assessed by a corneal silicone replica and subsequent confocal laser topometry.
Intraoperatively, the ablation site turned opaque, clearing after a couple of minutes. The resultant surface was rough; epithelization was uneven but not delayed. Postoperative pain was reported to be minimal. Subepithelial reactions were comparable to a 3+ haze and showed bubble-like inclusions, which slowly disappeared. By week 4, the corneal surface was even; a 1+ subepithelium haze persisted in case 1, while a clear ablation site was seen in case 2.
CONCLUSION: Areal corneal ablation with an Er:YAG laser that emits mid-infrared wavelengths seems possible. Although the thermally induced collateral damage is more pronounced, the wound healing pattern is comparable to 193 am PRK. This preliminary result has to be confirmed in normal eyes. [J Refract Surg. 1995;11:392-396.]
Oblique Versus Vertical-Horizontal Incision Orientation in Four-Incision Radial Keratotomy
Authors: Burillon C , Guigon B , Durand L 
Published: April 2021

ABSTRACT
BACKGROUND: Four-incision radial keratotomy is used for the correction of mild to moderate myopia. The traditional orientation of incisions was naturally on the horizontal and vertical meridians. We undertook a comparative study of oblique versus traditional four-incision radial keratotomy (orthogonal orientation) to show the advantage of an oblique incision orientation.
METHODSi A prospective study of two groups of 21 eyes was conducted: an orthogonal group with vertical-horizontal orientation of the four incisions, and an oblique group with four obliquely oriented incisions. Spatial contrast sensitivity, glare, and night vision tests were performed and results compared. The follow up period was 3 months.
RESULTS: Glare and contrast sensitivity were less affected with oblique orientation of incisions. There was no significant difference regarding night vision effects. We observed a decrease in induced astigmatism with oblique orientation.
CONCLUSION: The location of horizontal incisions within the palpebral fissure and the unequal lengths of horizontal and vertical incisions are responsible for ocular alterations. An oblique orientation is preferable to avoid glare, starburst, and induced astigmatism. [J Refract Surg. 1995;1 1:453459.]
Do Three-Piece PMMA IOLs Rotate After Implantation In the Capsular Bag?
Authors: Werblin Theodore P 
Published: April 2021

ABSTRACT
BACKGROUND: With the current interest in toric intraocular lenses (IOLs), it is critical to establish whether these implants rotate following cataract surgery. If there is continual rotation of the implant with capsular bag contraction, then the orientation of the astigmatic correction would be unstable and thus not clinically useful.
METHODS: Twenty-eight eyes were followed for up to 6 months postoperatively. These consecutive eyes were selected on the basis of demonstrating adequate dilatation following surgery, such that the points of haptic to optic insertion could be visualized with the slit-lamp microscope. Sequential photographs and comparisons of the orientation of the lenses postoperatively were performed.
RESULTS: With the exception of one lens implant, none of the 28 IOLs demonstrated significant rotation. Of the 16 eyes followed for 6 months, none demonstrated rotation of greater than 4 degrees, which was within experimental error.
CONCLUSIONS: Continued rotation of PMMA IOLs following implantation in the capsular bag seldom occurs. Thus, the concept of toric IOLs appears to be quite usable. [J Refract Surg. 1995;11:468-471.]
Combined Wedge Resection and Relaxing Incisions for Astigmatism After Penetrating Keratoplasty
Authors: Belmont Sandra C , Lazzaro Douglas R , Muller Jacqueline W , Troutman Richard C 
Published: April 2021

ABSTRACT
BACKGROUND: Videokeratography may provide information for surgical correction of astigmatism after penetrating keratoplasty. We used a combination of wedge resection and relaxing incisions to treat high refractive astigmatism after penetrating keratoplasty.
METHODS: Videokeratography using the normalized scale of the Topographic Modeling System was used as a guide in determining the location and the length of incisions and resections. Nine eyes were treated with both relaxing incisions and a wedge resection. All patients had more than 3.00 diopters (D) of refractive astigmatism. All patients were intolerant of spectacles or contact lenses. The depth of the corneal relaxing incisions was constant at 0.5 mm and the width of the corneal wedge resections was constant at 0.75 mm.
RESULTS: The relaxing incisions produced flattening of the steeper meridian and the wedge resection produced steepening of the flatter meridian. The average preoperative keratometric astigmatism was 7.44 D (range, 3.50 to 11.00 D) and the average refractive astigmatism was 5.56 D (range, 4.00 to 8.00 D). The average preoperative spherical equivalent was 0.08 D (range, -7.00 to 4.25 D). Postoperatively, the average keratometric astigmatism was 2.97 D (range, 1.00 to 5.00 D) and the average refractive astigmatism was 2.58 D (range, 0.00 to 5.00 D). The average postoperative spherical equivalent refraction was -0.32 D.
CONCLUSIONS: Combined corneal wedge resection and relaxing incisions appears to be effective in reducing high refractive astigmatism following corneal transplantation. [J Refract Surg. 1995;11:472-476.]
Epikeratoplasty for Myopia: 2-year Results and a Proposed Nomogram
Authors: Choi Sangkyung , Lee Jin H 
Published: April 2021

ABSTRACT
BACKGROUND: Epikeratoplasty for myopia is a relatively safe and reversible surgical technique that can result in large refractive corrections. However, it is also claimed that long-term stability and predictability are not satisfactory due to refractive regression and undercorrection.
METHODS: In an effort to improve predictability and stability of epikeratoplasty for myopia, we followed 24 cases for 2 years and isolated factors affecting the postoperative refractive results.
RESULTS: We found that better refractive results were achieved at 24 months postoperatively for cases in which the power of preoperative myopia was lower. Our investigations also disclosed no significant correlation between the surgical outcome at 24 months and patients' sex, age, and preoperative keratometric readings.
CONCLUSION: On the basis of our observations, we propose a new nomogram where higher powers of minus keratolenses, compared to the traditional prescription chart, should be selected for those with high preoperative myopia to result in improved long-term results with epikeratoplasty for myopia. This nomogram has not yet been clinically tested. [J Refract Surg. 1995;11:497-501.]
In Vivo Evaluation of a Collagen Corneal Allograft Derived From Rabbit Dermis
Authors: Kornmehl Ernest W , Bredvik Brian K , Kelman Charles D , Raizman Michael B , DeVore Dale P 
Published: April 2021

ABSTRACT
BACKGROUND: This study evaluates epithelialization, clarity, intraocular inflammation, and fibroblast ingrowth of a collagen corneal allograft derived from rabbit dermis.
METHODS: Dermal collagen fibers were dispersed intact and chemically modified to make them soluble. The allografts consisted of a fibrous, opaque peripheral zone and a central clear area. Twelve New Zealand white rabbits underwent penetrating keratoplasty with implantation of an allograft. The grafts were evaluated daily for clarity, anterior segment inflammation, and extent of reepithelialization with a slit-lamp microscope.
RESULTS: Epithelialization of the fibrous peripheral zone of the graft ranged from 0% to 90%. The central clear area did not epithelialize in any of the animals. Fibroblasts migrated into the peripheral zone in all eyes. Complications included ulceration of the central clear area in two eyes. There was no ulceration or leakage at the graft-host interface and no synechia, fibrous, or inflammatory retrocorneal membranes in any of the eyes.
CONCLUSIONS: Our study is the first to describe the method of modifying dermal type I collagen into a clear corneal allograft. Survival of the corneal collagen allograft beyond 1 month may be limited by several factors including lack of epithelialization of the central clear area. [J Refract Surg. 1995;11:502-506.]
Limitations of Erbium:YAG Laser Photorefractive Keratectomy
Authors: Mrochen Michael , Semshichen Vladimir , Funk Richard H W , Seiler Theo 
Published: April 2021

ABSTRACT
PURPOSE: The erbium:YAG laser (λ = 2.94 /¿m) has been considered promising as an alternative to the ArF excimer laser in photorefractive keratectomy (PRK). However, corneal application of this mid-infrared solid state laser is still plagued with various disadvantages compared to that of the ArF excimer laser (λ = 193 nm). We discuss the limitations of PRK with the erbiunuYAG laser.
METHODS: Measurements of ablation threshold, ablation efficiency, and thermal damage were done to compare the process of erbium:YAG laser photoevaporization to the ArP excimer laser. PRK procedures were performed on fresh enucleated pig corneas to investigate the morphology and surface roughness of the cornea after scanning-spot and fundamental mode photoablation. Surface roughness was measured by using a tactile surface reprofiling system.
RESULTS: The ablation threshold and the ablation efficiencies for the erbium:YAG laser are significantly higher compared to the ArF excimer laser. Collateral thermal damage decreases with a reduction of laser pulse duration to a minimum of approximately 5 /im. Scanning electron microscopy and surface roughness measurements of the corneal surface after erbiunuYAG laser treatment demonstrated higher surface roughness compared to ArF excimer laser treatments.
CONCLUSIONS: The erbium.YAG laser is not at present an alternative to the ArF excimer laser for photorefractive keratectomy. [J Refract Surg 2000;16:51-59]
Results of Photorefractive Keratectomy in Keratoconus Suspects at 4 Years
Authors: Bilgihan Kamil , Özdek Sengül C , Konuk Onur , Akata Fikret , Hasanreisoglu Berati 
Published: April 2021

ABSTRACT
PURPOSE: We studied the long-term results of photorefractive keratectomy (PRK) in keratoconus suspects detected by videokeratography (TMS).
METHODS: Bilateral inferior corneal steepening was detected in 6 candidates for PRK presenting with moderate myopia or astigmatism. Mean follow-up was 44.5 ± 4.4 months (range, 38 to 54 mo). Mean spherical equivalent refraction was -5.18 ± 1.60 D (mean sphere, -4.73 D; mean cyclinder, -0.92 D) which was stable for at least the preceding year. The quantitative measurement of inferior corneal steepening (I-S value) was greater than +1.60 (mean, 1.83 ± 0.11) in all eyes. An Aesculap Meditee Mel 60 excimer laser was used for the PRK procedures and mean follow-up was 44.5 months. Postoperative pachymetric measurements were also performed in 6 eyes.
RESULTS: Postoperative uncorrected visual acuity was 20/20 in 8 eyes (66.6%) and 20/32 or better in all eyes with a mean postoperative spherical equivalent refraction of -0.70 ± 0.74 D (mean sphere, -0.63 D; mean cyclinder, -0.39 D). Five eyes (41.6%) were within ±0.50 D spherical equivalent refraction. Inferior steepening was associated with thinning of the inferior cornea which was statistically significantly thinner than the superior thickness (Student's f-test, P < .05). There were no wound healing problems or any sign that the excimer laser adversely affected the cornea during follow-up.
CONCLUSIONS: Photorefractive keratectomy seems to be a safe procedure for reducing or eliminating myopia or astigmatism in keratoconus suspect eyes - most probably forme fruste keratoconus- with a stable refraction, but this may be different in eyes with early keratoconus, known to be a progressive disease. [J Refract Surg 2000; 16:438-4431
Implantation of a New Accommodative Posterior Chamber Intraocular Lens
Authors: Küchle Michael , Nguyen Nhung X , Langenbucher Achim , Gusek-Schneider Gabriele C , Seitz Berthold , Hanna Khalil D 
Published: April 2021

ABSTRACT
PURPOSE: A new, potentially accommodative posterior chamber lens (PCIOL) was designed based on principles elaborated by Hanna using finite element computer simulation methods. We report 3-month postoperative results in patients.
METHODS: In a prospective study, 12 eyes of 12 patients (age 45 to 87 yr) underwent phacoemulsification for cataracts and PCIOL implantation. The PCIOL, 1 CU, has haptics designed for anterior optic movement following ciliary muscle contraction. Patients were examined postoperatively after 1 and 2 days, 1, 2 and 6 weeks, and 3 months, and results were compared with a control group of 12 eyes that received standard PMMA or acrylic PCIOLs.
RESULTS: Surgery was uncomplicated and all PCIOLs were well-tolerated and stable with good centration in the capsular bag. The results were (mean ± SD [range] and median; 1 CU versus control PCIOL): near visual acuity (Birkhäuser reading chart at 35 cm) with best distance correction 0.34±0.17 (0.2 to 0.6), 0.3 (J10-J1, median J7) versus 0.15±0.07 (0.1 to 0.3), 0.15 (J16-J7, median J13), P=.001; subjective near point 59±10 cm (40 to 100 cm), 53.5 cm versus 93±20 cm (64 to 128 cm), 86 cm, P=.004; retinoscopic accommodative range 1.2 ± 0.4 D (0.63 to 1.5 D), 1.2 D versus 0.2±0.19 D (-0.25 to 0.5 D), 0.25 D, P<.001; decrease of anterior chamber depth after 2% pilocarpine 0.63±0.16 mm (0.40 to 0.91 mm), 0.63 mm versus 0.15±0.05 mm (0.08 to 0.20 mm), 0.17 mm, P<.001.
CONCLUSIONS: The new PCIOL appears to be safe at short to medium term. Our results indicate pseudophakic accommodation secondary to focus shift with this PCIOL. Additional larger and long-term studies are necessary for exact evaluation of safety and accommodative power of this new PCIOL. [J Refract Surg 2002;18:208-216]
Laser in situ Keratomileusus for Mixed and Simple Myopic Astigmatism With the Nidek EC-5000 Laser
Authors: Rueda Lizbeth , Pineda-Fernández Angel , Huang David , Nur Jorge 
Published: April 2021

ABSTRACT
PURPOSE: To evaluate the visual and refractive results of laser in situ keratomileusis (LASIK) for mixed and simple myopic astigmatism using bitoric ablation.
METHODS: A retrospective study was performed in 65 eyes of 38 consecutive patients to evaluate uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA) and cyclopegic and manifest refraction, before and 3 and 6 months after LASIK (Moria LSK-ONE microkeratome, Nidek EC-5000 excimer laser).
RESULTS: At 3 and 6 months after LASIK, 40 eyes of 24 patients (64.5%) were available for follow-up examination. Mean age was 25.9 ± 6.6 years (range 18 to 43 yr). Mean preoperative manifest spherical equivalent refraction was -1.40 ± 0.80 D (range -3.80 to +0.50 D), mean preoperative cylinder was -3.30 ± 1.30 D (range -1.00 to -6.00 D). At 6 months follow-up, mean manifest spherical equivalent refraction was +0.30 ± 0.46 D (range -0.38 to +1.88 D), mean cylinder was -0.73 ± 0.61 D (range -2.25 to 0 D). There was a 77.8% decrease in astigmatism magnitude. According to vector analysis, mean achieved vector magnitude was 80% of intended. Fifty percent (20 eyes) had a cylinder within ±0.50 D of emmetropia. Twenty-three eyes (57.5%) had a spherical component within ±0.50 D. Eighty-five percent (34 eyes) had postoperative UCVA of 20/40 or better. Ten percent (four eyes) lost two lines of Snellen BSCVA, whereas 35% (14 eyes) gained one or more lines.
CONCLUSIONS: Bitoric LASIK with the Moria LSK-ONE microkeratome and Nidek EC-5000 excimer laser was effective and safe for the reduction of cylinder in mixed and simple myopic astigmatism. Moderate undercorrection of the cylinder was evident. [J Refract Surg 2002;18: 234-238]
Laser in situ Keratomileusis and Diode Thermal Keratoplasty for Correction of Hyperopia From +5.00 to +10.00 Diopters
Authors: Rad Ahmad Salamat , Jabbarvand Mahmood , Farahvash Mohammad Mehdi , Kheradvar Arash 
Published: April 2021

ABSTRACT
PURPOSE: To evaluate the effects and safety of laser in situ keratomileusis (LASIK) and diode thermal keratoplasty (DTK) for correction of moderate to high hyperopia (+5.00 to +10.00 D).
METHODS: This prospective study included 30 eyes of 15 patients who had LASEK-DTK bioptics. The median age of the patients was 50.5 years. LASES was performed using a Nidek EC-5000 excimer laser system and DTK by a Prolaser DTK laser, 2 months after LASES. Follow-up ranged from 9 to 12 months (mean, 10.5 mo).
RESULTS: The mean preoperative spherical equivalent refraction was +8.25 ± 0.25 D and mean postoperative was +1.00 * 0.50 D. The preoperative best spectacle-corrected visual acuity (BSCVA) was «20/40 in 10 eyes and 2*20/25 in 20 eyes. Postoperatively, BSCVA was «20/40 in 8 eyes and 2*20/25 in 22 eyes. No significant intra- or postoperative complications occurred.
CONCLUSION: LASDX-DTK bioptics for correction of moderate to high hyperopia (+5.00 to +10.00 D) was safe and effective. In this method, two different ablative and non-ablative laser systems were used to compensate for regression, which is the most important concern in the correction of hyperopia. [J Refract Surg 2002;18(suppl): S318-S320]
Reduction of Spherical Aberration: Experimental Model of Photoablation
Authors: Vinciguerra Paolo , MD Maria Ingrid Torres , Camesasca Fabrizio I 
Published: April 2021

ABSTRACT
PURPOSE: Several authors have suggested that a compound ablation for myopia may reduce postoperative spherical aberration. This technique consists of treating myopic ablation by increasing the preoperative sphere 25% and applying a hyperopic ablation of 25% of preoperative sphere. Theoretically, this technique allows optical zone increase, and elimination of the peripheral red ring.
METHODS: Eight eyes of four patients with bilateral moderate myopia received laser epithelial keratomileusus (LASEK) with the Nidek EC-5000 excimer laser. In each patient, one eye was treated with the compound ablation (Group 1), and the fellow eye with the standard cross-cylinder technique (Group 2). Mean preoperative refraction and BSCVA were comparable within the two groups.
RESULTS: At 1 month postoperatively, UCVA was significantly better in Group 2 than in Group 1 eyes. In neither group was clinically important haze seen. Subjectively, all patients rated more satisfactorily the eye that received the standard ablation (Group 2) than the one treated with compound ablation (Group 1). Evaluation of keratorefractive indices derived from corneal topography revealed significantly better eccentricity in Group 2 eyes. Corneal topography showed the presence of a central island in all Group 1 eyes.
CONCLUSION: The compound ablation hypothesis was not confirmed. Presence of central island in compound-treated eyes induced significant optical aberrations. [J Refract Surg 2002;18(suppl): S366-S370]
Are Changes in Ocular Aberrations With Age a Significant Problem for Refractive Surgery?
Authors: Marcos Susana 
Published: April 2021

ABSTRACT
We discuss current knowledge about the change of aberrations with aging, cataract surgery, and laser in situ keratomileusis (LASER) for myopia. Based on this evidence, we speculate about the long-term expectations for postoperative LAStK eyes in terms of aberrations. Standard myopic LASIK surgery produces a significant increase in aberrations, particularly corneal spherical aberration, which changes to positive values. Aberrations increase with age, and in particular, the spherical aberration of the crystalline lens shifts toward positive values. Therefore, no compensatory effect is expected to occur with age after standard myopic LASLK, but rather the unusually high amount of aberrations in postoperative LASLK patients is expected to worsen with age. The amount of aberrations in patients after cataract surgery with implantation of standard intraocular lenses (IOLs) is higher than in normal young subjects. If an ideal customized ablation (not inducing aberrations and reducing naturally existing aberrations) is ever possible, the perfect correction will not last (due to the change of aberrations with age), and aberrations of the crystalline lens corrected on the cornea are likely to reappear after conventional cataract surgery. Potential benefits of customized IOLs for cataract surgery and improved optics in older patients are discussed. [J Refract Surg 2002; 18:S572-S578]
Biomechanics of the Cornea and Wavefront-guided Laser Refractive Surgery
Authors: Roberts Cynthia 
Published: April 2021

ABSTRACT
PURPOSE: Wavefront-guided laser refractive surgery induces postoperative optical aberrations that are not explained by the ablation profile.
METHODS: A conceptual model is presented for a potential mechanism of surgically-induced corneal shape change that is dependent on structural modification, rather than ablation profile.
RESULTS: Examples are provided from clinical and basic studies that are consistent with the proposed model.
CONCLUSION: Corneal biomechanical response to ablative surgery may significantly affect outcomes, and should be taken into account when planning customized procedures. [J Refract Surg 2002;18:S589-S592]
Effect of Aging on Ocular Light Scatter and Higher Order Aberrations
Authors: Kuroda Teruhito , Fujikado Takashi , Ninomiya Sayuri , Maeda Naoyuki , Hirohara Yoko , Mihashi Toshifumi 
Published: April 2021

ABSTRACT
PURPOSE: To study the effect of aging on ocular light scatter and higher order aberrations in humane.
METHODS: Seventy-six eyes of 76 normal subjects who had refractive errors but no ocular disease were studied« Their age ranged from 4 to 69 years (mean 34.8 ± 5.8 yr). Both light scatter and total higher order aberrations were simultaneously and quantitatively measured by a Hartmann-Shack sensor for the central 4-mm-diameter pupil. Higher order aberrations were calculated from the Zernike polynomials up to the 4th order. The amount of light scatter was estimated by using the diameter of the point spread functions (PSFs) of the Hartmann images. A correction was made for the effect of the aberrations on the width of the images. Linear regression analysis was performed to investigate the effect of aging on light scatter and total higher order aberrations.
RESULTS: A significant correlation was found between scatter and age (Spearman rank correlation coefficient, r = 0.501, P - .001). Also, the total higher order aberrations increased significantly with age (r = 0.323, P = .005). The total higher order aberration and scatter index were not statistically significantly correlated (r s 0.184, P = .112).
CONCLUSIONS: These results indicate that scatter was better correlated with age than higher order aberrations. [J Refract Surg 2002; 18: S598-S602]