bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictive Value of Temporal Retinal Disease in Retinopathy of Prematurity
Authors: Paysse Evelyn A , Coats David K , Sprunger Derek T
Published: April 2021

ABSTRACT

Purpose: Screening examinations for retinopathy of prematurity (ROP) can be stressful to the premature infant. The temporal retina is the most easily visualized area of the peripheral retina. This study was undertaken to determine whether evaluation of the temporal peripheral retina provides a reliable indicator of the ROP status of the entire retina.

Methods: A total of 690 ROP eye examinations were performed on 156 premature infants. Eye examinations of 95 patients were reviewed retrospectively and of 61 patients prospectively. All patients were born at less than 34 weeks estimated gestational age (EGA) and had a birth weight less than 1600 g. No examinations were performed prior to 4 weeks of age. Each eye examination was considered independently. The fundus examination was recorded using the International Classification of Retinopathy of Prematurity. The temporal four clock hours of retina were classified as the "temporal" retina. The remainder of the peripheral retina was classified as "nontemporal."

Results: A highly significant correlation (Pearson correlation coefficient=0.88) between the severity (ie, stage) of temporal ROP and the severity of nontemporal ROP was noted. The status of temporal ROP was found to be more advanced or the same as nontemporal retina in 91.2% of the examinations. Nontemporal disease was found to be more severe than temporal disease in 8.8% of the examinations, but only 0.4% of examinations indicated nontemporal disease that was worse than temporal disease by more than one stage.

Conclusions: The temporal retinal disease status in ROP is strongly predictive of the disease status of the entire retina. An abbreviated retinal examination of the temporal four clock hours provides a reliable indicator of the highest stage of ROP present in the entire retina. Such a screening examination, although not recommended for routine screening, may be useful when a complete ROP examination cannot be performed because of physiologic instability or poor visibility.
Random Dot Stereoacuity of Preschool Children
Authors: Birch Eileen , Williams Cathy , Hunter Jeffrey , Lapa Maria Cecilia
Published: April 2021

ABSTRACT

Purpose: Commercially available book-format random dot stereopsis tests for children are quick and simple to use, but provide accurate measurement of stereoacuity only in children age 5 years or older. Alternative methods for preschool children provide only pass/fail information or require lengthy laboratory-based protocols. To address the need for a quick and accurate measure of random dot stereoacuity in the preschool age range, we developed a new book-format random dot stereoacuity test.

Methods and results: A total of 25 potential shapes for the new test were evaluated in a group of 43 healthy fullterm children aged 3 years±2 months. Eleven shapes that were identified successfully by more than 95% of the 3-year-olds were selected to be incorporated into the preschool stereotest. The preschool random dot stereotest books were administered to more than 1000 normal children and pediatric patients in multiple settings: a research laboratory (Retina Foundation SW), a population screening project (University of Bristol, UK), eye clinics (Children's Medical Center, Dallas, Tex), and a day care center (Federal University, São Paulo, Brazil). Randot, Lang 1, Frisby, or Titmus stereoacuity tests also were administered. Orthoptic or ophthalmic examinations were obtained for all children as a gold standard. Outcome measures were success rate and concordance with the clinical examination. Sensitivity, specificity, and accuracy exceeded 0.90 both in clinical and screening settings.

Conclusions: The preschool random dot books had a higher success rate than other tests in the preschool age range and provided accurate measurement of stereoacuity in the 3- to 5-year-old age range.
Tucking the Inferior Oblique Muscle Into Tenon's Capsule Following Myectomy
Authors: Lueder Gregg T
Published: April 2021

ABSTRACT

Purpose: Myectomy of the inferior oblique muscle is a common procedure used to correct overaction of this muscle. Previous descriptions of the surgery have not discussed how the surgeon should handle the proximal muscle stump following myectomy. This study examined the effectiveness of inferior oblique muscle myectomy with tucking of the muscle into Tenon's capsule for treatment of inferior oblique muscle overaction.

Methods: The procedure was studied prospectively in 22 patients who underwent 32 inferior oblique muscle myectomies. In 18 patients, the intraoperative behavior of the inferior oblique muscle was recorded. Complete ocular motiUty examinations were performed before and after surgery. Success was defined as the elimination of inferior oblique muscle overaction and the elimination of hypertropia secondary to persistent ipsilateral inferior oblique muscle overaction in primary gaze.

Results: The surgery corrected inferior oblique muscle overaction in 94% of eyes. Hypertropia secondary to persistent ipsilateral inferior oblique muscle overaction was eliminated in 92% of patients. There was no correlation between outcome and the intraoperative behavior of the inferior oblique muscle.

Conclusion: Tucking of the inferior oblique muscle stump into Tenon's capsule is recommended following inferior oblique myectomy. This procedure is safe and effective for correcting Inferior oblique muscle overaction.
A Framework for the Emergency Evaluation of the Suicidal Patient
Authors: DiVasto Peter V , West Donald A , Christy Joan E
Published: April 2021

ABSTRACT

With increasing frequency, emergency room personnel face the anxiety of assessing suicide potential. The authors have developed and present here a mnemonic SAD CHILDREN) which should facilitate the evaluation of potential in attempted or threatened suicide patients.
Development and Evaluation of Social Skills Training for Schizophrenic Patients in Remission
Authors: Miller Thomas W , Wilson Gertha C , Dumas Mary A
Published: April 2021

ABSTRACT

Investigated were measures of self-esteem, selfperceived attitudinal dimensions and locus of control to assess the effects of group social skills training for schizophrenic psychiatric inpatients. A pretest, posttest control group design was employed utilizing forty subjects currently in treatment. It was hypothesized that short-term cognitively structured group therapy would realize significant improvement in self-esteem, internal locus of control and assertive attitude change. Significant mean differences between the treatment group's level of self-esteem, perceived assertive behavior and internal locus of control as a result of treatment were realized. Discussion of training methodology, issues and import for clinical applications and research are discussed.
Family Aspects of Trichotillomania
Authors: Lantz James E , Early J Patrick , Pillow Walter E
Published: April 2021

ABSTRACT

This paper reports on the utilization of family system concepts in the understanding and treatment of trichotillomania. The paper discusses family interactional aspects of trichotillomania in four families as well as a description of assessment, intervention and follow-up procedures used with each family group.
Comparison of Psychiatric-Mental Health Nursing Education Objectives: Consumers, Educators, and Practitioners
Authors: Mansfield Elaine , Garrard Judith , Hausman William , Howey Mary K
Published: April 2021

ABSTRACT

This consumer-nurse study was part of a larger project, Research in Mental Health Education, which compared the priorities of educa tors and practitioners within and between three core mental health professions and between the professionals and consumers. In the consumer-nurse portion of the study, the objectives for graduate education in psychiatricmental health nursing were validated by psychiatricmental health nursing educators (N= 20) based in four university programs in the East, West, and Midwest. Another sample of nurse educators and practitioners in this specialty area, drawn from nine states, prioritized these objectives. A separate deck of objectives for mental health professionals was generated and prioritized by consumers (N= 15) who were members of the Mental Health Association of Minnesota. Standardized procedures for generating and validating the objectives for nurses and consumers and the same task, the Priority Sort, were used by all subjects, nurses, and consumers, to prioritize the objectives. Similarities and differences between nurses and consumers are discussed. Differences between nurse educators and practitioners, which are statistically significant, also are described. Implications for consumer and practitioner input into curricular decisions are discussed as well as interdisciplinary courses that could conserve faculty time and budgetary resources.
Do It Gradually, Advises Sleep Expert
Authors: Anonymous
Published: April 2021

Kicking the Sleeping Pill Habit?
ALTERED BRAIN METABOLISM
Authors: Anonymous
Published: April 2021

SCHIZOPHRENIA
UNDERSTANDING PLAY
Authors: Anonymous
Published: April 2021

TOY LIBRARY
Depression Common Among Elderly
Authors: Anonymous
Published: April 2021

25% of Geriatric Population May be Affected
Who Are They? Identifying and Treating Adult Children of Alcoholics
Authors: Tesson Bonnie M
Published: April 2021

By using good assessment techniques and identifying ACoAs on the unit, nurses can provide support, teach, plan interventions, and assist in the process of appropriate referrals.
Under Wraps: Prevalence of Staff-Patient Sexual Interactions on Inpatient Units
Authors: Munsat Elizabeth M , Riordan Janette J
Published: April 2021

Does hospital size or type of ownership contribute to the prevalence of sexual interactions between staff and patients on inpatient units?
My Role as a Consumer-Provider: Challenges and Opportunities
Authors: Francell Edward G
Published: April 2021

In this first-person account, Edward G. Francell, Jr., MSW, discusses his history of bipolar disorder and panic disorder with agoraphobia, and how his experience helps him help others.
Self-Harm Among Adolescents with Developmental Disabilities: What Are They Trying to Tell Us?
Authors: Murray Lee
Published: April 2021

ABSTRACT

Self-harm behavior exhibited by adolescents with developmental disabilities can be the most challenging behavior for caregivers and health care professionals to address. Past interventions have taken a behavioral approach and focused on functional analysis to guide assessment and treatment. However, self-harm behavior is becoming more recognized as a means of communication.

Therefore, it is important for health care professionals and caregivers to listen to adolescents' attempts to communicate and try to understand the meaning of the behavior. Early assessment is crucial to understanding the meaning of the behavior, and early intervention is necessary to prevent escalation or chronicity. Thorough assessment guides interventions and must be implemented in the context of clients' families and social world, and the broader community. Establishment of trusting relationships among adolescents, their families, and health care professionals is imperative.

This article discusses self-harm behavior from a psychosocial perspective related to prevalence, onset, purpose, maintenance, and escalation. It also introduces a comprehensive framework to guide assessment and intervention.
In Vivo Evaluation of Epikeratophakia Lenses By Means of Scheimpflug Photography
Authors: Busin Massimo , Spitznas Manfred , Laser Heike , Leyendecker Marion , Hockwin Otto
Published: April 2021

ABSTRACT: The recovery of clarity in frozen, lyophilized human tissue lenticules used for epikeratophakia has been a matter of controversy. According to some authors, several months are necessary for the lenticules to resume normal transparency; others report clinical experience of much shorter times. Up to now, objective documentation of such findings has not been substantiated. We used a Topcon SL-45 camera to photograph four eyes that underwent epikeratophakia, preoperati vely and at 2, 4, 6, and 8 weeks after surgery, and analyzed the film negatives by linear microdensitometry. The degree of film blackening, that is the density of the tissue, was expressed graphically by peaks of various height measured in millimeters. Best spectacle corrected Snellen visual acuity was also recorded. Similar measurements of corneal transparency were performed in 20 healthy adult volunteers whose best corrected spectacle visual acuity was 20/20.

In the four operated eyes (two keratoconus, one aphakia, and one myopia), the light scattering was increased in both the host cornea and the donor lenticule. The lenticule had a considerably increased light scattering in all patients at both 2 and 4 weeks after surgery, but was comparable to that of unoperated corneas in three of four patients at 6 weeks. [Refractive & Corneal Surgery 1989; 5:155-160.1
Adjustment of Single Continuous Suture to Control Astigmatism After Penetrating Keratoplasty
Authors: McNeill James I , Wessels Izak F
Published: April 2021

ABSTRACT: The presence of high amounts of regular and irregular astigmatism after penetrating keratoplasty has been a major challenge for corneal surgeons. We have devised a technique of suture adjustment which redistributes the tension in a single continuous 10-0 nylon suture according to keratometric findings and overcomes some of the limitations of other published methods for reducing penetrating keratoplasty astigmatism. Suture adjustment Is performed at the slit-lamp microscope using topical anesthesia, from as early as the first postoperative day. The effects are controllable, reversible, stable, and can achieve relaxation or tightening of any meridian. Of 330 consecutive eyes undergoing penetrating keratoplasty, 205 required and underwent one or more suture adjustments. The mean keratometric astigmatism after suture adjustment was 2.87 D (SD=187), compared to a preceding consecutive series of 136 eyes without suture adjustment with 4.80 D (SD =3.13) mean astigmatism (P< 0.0001). This effect persisted even when the suture had to be removed (P<0.0001). Infection did not occur. Only five eyes (2.4%) experienced a broken suture, which was readily spliced. We recommend adjustment of a single continuous suture, when moderate to severe astigmatism is present after a penetrating keratoplasty. [Refractive and Corneal Surgery 1989; 5:216-223.]
Refractive Results of Successful Penetrating Keratoplasty, Intraocular Lens Implantation With Selective Suture Removal
Authors: Pradera Ignacio , Ibrahim Osama , Waring George O
Published: April 2021

ABSTRACT: The refractive outcome in 44 eyes that had combined penetrating keratoplasty and intraocular lens insertion, with at least ó months follow-up, was analyzed. All patients were operated on by the same surgeon using two types of trephines in all but one eye, and one suturing technique with nylon or dacron sutures. The intraocular lens power was calculated using SRK Il formula with an assumed average postoperative keratometry of 45 D. The first refraction showed that the mean spherical equivalent was - 0.20 ± 3.45 D, the mean refractive astigmatism was 5.H ± 2.48 D and the average keratometry had a mean of 44.42 ± 3.19 D. Modulation of postoperative astigmatism was done by selective removal of tight interrupted sutures, taking out one suture or maximally two sutures per visit, based on refraction, keratometry, and keratography criteria. The total number of sutures removed had a mean of 2.5 ± 2.2 with a mean total number of visits of 5.3 ± 2.0. The interval between visits had a mean of 4.5 ± 1.9 weeks and the total duration of the suture removal phase was about six months. At the end of the refractive rehabilitation period, 73% of cases had a spherical equivalent between +3.0 D and -3.0 D and 61% of cases had an average keratometry within 2.5 D from our assumed value of 45 D. The mean postoperative refractive astigmatism was 2.5 ± 1.5; 55% of cases had 3.0 D or less of astigmatic error and 90% of cases were within 4.0 D of postoperative astigmatism. [Refractive and Corneal Surgery 1989; 5:231-239.]
The Anchor Suture for Securing Loosened, Continuous Sutures in Penetrating Keratoplasty
Authors: Kenyon Kenneth R , Grene R Bruce
Published: April 2021

ABSTRACT: To secure a penetrating keratoplasty donor button, a continuous suture is both less time consuming to place and easier to remove. Infrequently, however, the continuous suture may loosen or break prematurely. For this purpose we propose the anchor suture as a simple technique to restore a tight, continuous suture and a secure wound. [Refractive and Corneal Surgery 1989; 5:268-270.]
Light Microscopic and Ultrastructural Findings in Failed Epikeratoplasty
Authors: Grossniklaus Hans E , Lass Jonathan H , Jacobs Gretta , Margo Curtis E , McAuliffe Kevin M
Published: April 2021

ABSTRACT: Corneal buttons from two patients with failed epi keratoplasties requiring penetrating keratoplasty were examined by light and transmission electron microscopy. Penetrating keratoplasty was performed for lenticule scarring In the first case (adult aphakia) and inadequate best corrected visual acuity in the second case (keratoconus). Findings included decreased lenticule keratocytes and electron-dense, fibrillogranular material associated with either lenticule or recipient keratocytes in both corneas and defects in Bowman's layer in one cornea. In addition, light and electron microscopic evidence consistent with recipient keratocyte migration into the lenticule was demonstrated in one case. These findings were compared with three previous cases. [Refractive and Corneal Surgery. 1989; 5:296-301.]
Preliminary Evaluation of Two Experimental Surgical Adhesives in the Rabbit Cornea
Authors: Robin Jeffrey B , Lee Chia F , Riley Jerda M
Published: April 2021

ABSTRACT: We examined the clinical and histopathologic effects of the instillation of two surgical adhesives in the corneal stroma of rabbits. The adhesives examined in this study included a butyl-2cyanoacrylate (CA) and a combination of a musselderived polyphenolic protein (MAP) with an enzyme polymerizer (COX). In this study, either one of the adhesives or balanced saline solution (as a control) was instilled directly into the corneal stroma following the surgical creation of a perilimbal intralamellar pocket. Animals were examined on a regular basis for a 60-day period following instillation and, at predetermined time points, sacrificed for histopathologic evaluation. The group of animals that received intracomeal instillations of CA consistently manifested early and progressive stromal neovascularization of the affected corneas. Histopathologic examination confirmed the progressive neovascularization, as well as a noticeable inflammatory response surrounding the adhesive. In contrast, instillation of the MAP-COX adhesive produced neovascular and inflammatory responses that were later in onset and milder in degree than those observed with CA. In this experimental model, the MAP-COX adhesive appeared to be better tolerated than did the CA. [Refractive and Corneal Surgery. 1989; 5:302-306].
Corneal Topography Using Rasterstereography
Authors: Arffa Robert C , Warnicki Joseph W , Rehkopf Paul G
Published: April 2021

ABSTRACT: Rasterstereography is a new method of determining the topography of the comea. Unlike Placido disc types of systems it does not depend on the reflectivity of the corneal surface, and it can provide information about the entire corneal, limbal and interpalpebral conjunctival surfaces. Since a smooth reflective surface is not required, images can be obtained with epithelial irregularity or defects, sutures, or stromal ulceration. A grid of horizontal and vertical bars of light is projected onto the cornea, and the pattern of the grid on the ocular surface is determined by its topography. The image is obtained by a video camera, and digitized, stored, and analyzed by an image processor. A three dimensional image of the corneal surface, contour maps of corneal elevation, and corneal curvature can be displayed. [Refractive and Corneal Surgery 1989;6:414-417].
Lipid Deposits Posterior to Impermeable Intracorneal Lenses in Rhesus Monkeys: Clinical, Histochemical, and Ultrastructural Studies
Authors: Rodrigues Merlyn M , McCarey Bernard E , Waring George O , Hidayat Ahmed A , Kruth Howard S
Published: April 2021

ABSTRACT: Synthetic materials are being evaluated for their potential long-term use in corneal refractive surgery. Clinical and histopathologic studies were performed with polymethylmethacrylate (PMMA) and polysulfone intracorneal lenses in rhesus monkey eyes that were followed for up to 3 years. The 5 mm diameter lenses were placed in the deep posterior corneal stroma of four eyes. Fine, polychromatic crystalline deposits formed a layer posterior to the implants. Enucleated eyes had the corneas either frozen for histochemistry or fixed for electron microscopy. Special stains included oil red 0 and filipin on fresh frozen tissue. The cornea, with a PMMA intracorneal lens showed myriad crystalline aggregates in the deep corneal stroma behind the implant. These crystalline deposits stained positively with oil red 0 and with filipin indicating the presence of neutral fat as well as unesterified cholesterol. The polysulfone implant showed no evidence of crystalline deposits histologically but was surrounded by homogeneous aggregates that could represent nonspecific reaction to the lens material or protein deposits. Electron microscopy of all four corneas revealed dissolved lipid aggregates and laminated electron dense material that were most abundant posterior to the implant where the keratocytes appeared disintegrated. The PMMA lens appeared to induce lipid keratopathy. [Refractive and Corneal Surgery 1990;6:32-37]
Delayed Sterile Keratitis Following Radial Keratotomy Requiring Corneal Transplantation for Visual Rehabilitation
Authors: Geggel Harry S
Published: April 2021

ABSTRACT: Delayed keratitis is an unusual complication ot radial keratotomy surgery. A case of documented sterile keratitis involving four adjacent nasal incisions occurred 34 months following a 16-incision radial keratotomy procedure. Multiple cultures and biopsies failed to show a pathogen. The keratitis was confined to the incisional area without involvement of the intervening stroma. A penetrating keratoplasty was necessary to restore useful vision. Clinical and pathological studies documented delayed corneal wound healing. [Refractive and Corneal Surgery 1990;6:55-58]
Scanning Electron Microscopic Evaluation of the Effects of Intracameral Injection of Cyanoacrylate in the Rabbit
Authors: Macsai Marian , Kuczak Jerry , Robin Jeffrey B
Published: April 2021

ABSTRACT: We examined, using scanning electron microscopy, the effects of the injection of an isobutyl cyanoacrylate into the rabbit anterior chamber. Injection of the adhesive produced a rapidly polymerized mass that remained in the anterior chamber throughout the course of the study. Additionally, an active inflammatory response was noted in the anterior chamber, characterized by a progressively enlarging "cocoon" of fibrin and inflammatory cells surrounding the polymerized adhesive, as well as inflammatory cells in the trabecular meshwork. Following cyanoacrylate injection, the corneal endothelial cells were noted to be swollen for the first 14 days of the study. [Refractive and Corneal Surgery 1990;6:193-196.]
Corneal Light Scattering After Excimer Laser Photorefractive Keratectomy: The Objective Measurements of Haze
Authors: Lohmann Chris P , Timberlake George T , Fitzke Fred W , Gartry David S , Muir Malcolm Kerr , Marshall John
Published: April 2021

ABSTRACT

Background: After photorefractive keratectomy using excimer lasers (193 nm), most corneas show a marginal loss of transparency (haze) and the assessment of its magnitude in clinical studies has been subjective. To address this problem, we have developed a new device for the objective measurement of haze by measuring corneal light scattering.

Methods: A CCD-camera was fixed at 40° to a slit-lamp microscope and connected via frame-grabber to a computer. By incorporating polarizing filters, the system could discriminate between reflected and scattered light. The intensity of light coming from the cornea was measured in gray scale levels using in-house image analysis software. The system was calibrated against three different sizes of microspheres (0.25, 0.50, and 5.00 µm) which corresponded to the size of cellular and extracellular elements known to occur at sites of corneal surgery. Data were obtained from three treated human eyes with measurements before treatment and at five different postoperative intervals with a maximum follow up of 4 months.

Results: All three sizes of microspheres caused disturbances in gray scale levels (30 to 255 units) in the same range of those observed in corneal measurements. Disturbances in corneal light scattering were noted from 1 week postoperatively and persisted throughout the period of observation. We observed an increase in reflected and scattered light until the 2nd postoperative month followed by a subsequent decline.

Conclusions: It appears that this device is very useful to detect and measure objectively disturbances in corneal transparency after excimer laser photorefractive keratectomy. (Refract Corneal Surg 1992;8:114-121.)
One-Year Results of Excimer Laser Photorefractive Keratectomy for Myopia
Authors: Salz James J , Maguen Ezra , Macy Jonathan I , Papaioannou Thanassis , Hofbauer John , Nesburn Anthony B
Published: April 2021

ABSTRACT

BACKGROUND: Excimer laser photorefractive keratectomy tor the correction of myopia is presently under investigation in the United States by the Food and Drug Administration (FDA). The Phase 1 1 -B FDA study is being conducted on 75 normally sighted myopic eyes utilizing three currently available excimer lasers. This report presents the 1 -year results on 12 myopic eyes treated with the VISX excimer laser system at the Ellis Eye Center at Cedars-Sinai Medical Center in Los Angeles under the Phase H-B FDA protocol.

METHODS: Twelve eyes of 12 patients with myopia between - 1.75 and -5.00 diopters underwent 193 nm argon/fluoride excimer laser photorefractive keratectomy. The epithelium was mechanically removed, and fixation was accomplished with a suction ring which provided nitrogen flow across the corneal surface. The computer controlled corneal ablations were 5.00 mm in diameter and were accomplished with an iris diaphragm closing from large to small.

RESULTS: The preoperative spherical equivalent myopia was -3.50 D (SD = 1.02) and the postoperative myopia was -0.25 (SD = 0.48). Eleven of the 12 patients achieved an uncorrected visual acuity of 20/30 or better and were corrected to within ±0.50 D of emmetropia. All corneas demonstrated a mild reticular subepithelial haze which was barely visible at 1 year. There were no visionthreatening complications and none of the eyes experienced a loss of best corrected visual acuity.

CONCLUSIONS: In this small trial, the excimer laser appears to be capable of accurately changing the refractive power of the cornea for the correction of myopia with minimal side effects. Only when larger numbers of patients undergo the procedure will we be able to determine the safety and efficacy of photorefractive keratectomy as a refractive surgical procedure Refract Corneal Surg 1992;8:269-273.)

RÉSUMÉ

INTRODUCTION. La kératectomie refractive lamellaire au laser excimer pour Ia correction de la myopie est maintenant un sujet d'investigation chez la Food and Drug Administration (FDA) aux Etats-Unis. On est en train de conduire la phase H-B de l'étude clinique chez 75 yeux myopes avec une potenìiaìiìé de vision de 10/10° en utilisant trois lasers maintenant disponibles. Cette communication présente les résultats de 12 yeux myopes traités aux VISX système de laser excimer chez The Ellis Eye Center au Cedars-Sinai Medical Center à Los Angefes, selon le protocole de la phase M-B de la FDA, et suivis depuis une année.
Silicon Cast Method for Quantification of Photoablation
Authors: Bachmann Werner , Jean Benedikt , Bende Thomas , Seiler Theo , Hibst Raimund , Thiel Hans-J
Published: April 2021

ABSTRACT

BACKGROUND: Topometry and measurement of photoablation patterns are key questions for keratorefractive photoablation. Ablation rates have been determined previously by either tissue perforation or by micrometry performed on histologic sections.

METHODS: A three-dimensional cast of cornea after irradiation was made by using a twocomponent silicon gel that polymerizes within minutes, thus preserving the corneal topography immediately after photoablation. Polymerization is athermal and nontoxic. The resulting silicon blocks were cut perpendicularly to the anterior surface and measured by calibrated light microscopy.

RESULTS: The silicon surface is extremely smooth and the accuracy of the cast is better than 0.25 µ. Reproducibility and long-term stability were demonstrated for casts of photoablated polymethylmethacrylate. Thus, ablation rates and profile, volumetry, and topometry can be determined following laser ablation. The method has been applied for 193-nanometer excimer laser in vitro irradiation of the human cornea. Ablation rates in Bowman's layer and stroma for various radiant energies and distinct pulse numbers were found to be in agreement with published data, and an incubation effect for the first laser pulses could be demonstrated.

CONCLUSIONS: The method is nondestructive, accurate, inexpensive, practical, and reduces requirements for laboratory animals. [Refract Corneal Surg 1992;8:363-367.)

RÉSUMÉ

INTRODUCTION. La topométrie et l'analyse directe des impacts après photoablation sont des questions d'importance pour le resurfacage corneen après laser. Le taux de photoablation a été précédemment déterminé par différentes techniques: perforation du tissu ou microanalyse sur coupe histologique.

MÉTHODES. Une empreinte en 3 dimensions (3D) après irradiation a été réalisée par l'utilisation de deux gels de silicone polymérisant en quelques minutes, en préservant ainsi, l'empreinte de la topographie coméenne après photoablation. La polymérisation est non toxique et ne produit aucun dégagement thermique. L'empreinte en silicone est alors coupée perpendiculairement à la surface antérieure et est mesurée à l'aide d'un microscope optique calibré.

RÉSULTATS. La surface en silicone est extrêmement lisse et la fiabilité de l'empreinte est supérieure à 0.25 micromètre. La reproductibilité et la stabilité de la technique ont été démontrées pour des répliques de PMMA. Le profil, le taux d'ablation, le volume, la topométrie peuvent ainsi être déterminés après photo-ablation. La méthode a été appliquée pour le laser excimer à 193 nanometres sur des cornées humaines (in vitro). Les taux d'ablation de la membrane de Bowman et du stroma cornée, pour différentes densité d'énergie et nombre d'impacts ont été trouvés en concordance avec les données publiées à ce jour et l'effet de préparation du substrat pour les premiers impacts pourrait être mis en évidence.
Corneal Wound Healing After Excimer Laser Ablation in Rabbits: Expanding Versus Contracting Apertures
Authors: Campos Mauro , Cuevas Kevin , Shieh Emil , Garbus Jenny J , McDonnell J
Published: April 2021

ABSTRACT

BACKGROUND: Photorefractive keratectomy for myopia can be performed using an expanding or contracting iris diaphragm, either of which allows for greater ablation centrally and less tissue ablation toward the edge of the treatment zone.

METHODS: To compare the effects of these two strategies, eight rabbits underwent bilateral 5.00diopter myopic ablations, performed with a contracting diaphragm in one eye and an expanding diaphragm in the other.

RESULTS: The rate of epithelial healing and degree of anterior stromal haze, monitored by a masked observer, were similar for the two groups, as was the amount of corneal flattening.

CONCLUSIONS: These results in rabbit corneas do not suggest a particular advantage of either the expanding or contracting apertures for achieving central corneal flattening in photorefractive keratectomy. Refract Corneal Surg 1992;8:378-381.)
Surgical Correction of Hyperopia: A New Experimental Approach Using X-Incision and Suture Technique in Rabbits
Authors: Lee Jin H , Park Kiho , Lim Kyung J
Published: April 2021

ABSTRACT

BACKGROUND: A new experimental surgical technique to correct hyperopia by steepening the central corneal curvature was performed on the eyes of rabbits.

METHODS: After X-shaped incisions at four quadrants of the paracentral cornea, four deep, transverse interrupted sutures were placed across the incisions and the knots were tightened to compress the corneal tissue in the direction of the suture. Twenty-three eyes of 12 albino rabbits were divided into group A (7 eyes) with a 4-millimeter diameter clear zone, group B (9 eyes) with a 6-millimeter diameter clear zone, and control group C1 consisting of 7 contralateral eyes of group A without any incision or suture.

RESULTS: There was significant (p < .01) steepening of the central cornea as measured by the keratometer at postoperative 8 weeks in group A (+1.88 diopters) and group B (+1.68 D) compared with that of the control group C (-3.44 D). The difference in effect of hyperopic correction between groups of A and B was not statistically significant.

CONCLUSIONS: This procedure serves only as an experimental model of corneal response to incisions and sutures and is not for use in human corneas. (Refract Corneal Surg 1992; 8:389-393.)
Results of Photorefractive Keratectomy for Myopia With the Technolas Keracor 116 Excimer Laser
Authors: Kaskaloglu Mahmut
Published: April 2021

ABSTRACT

BACKGROUND: The refractive results of first consecutive 157 myopic eyes undergoing photorefractive keratectomy with the Technolas Keracor 116 excimer laser are presented with a 6-month follow up.

METHODS: Preoperative refractive errors (spherical equivalent) ranged between -1.75 diopters (D) and -20.00 D (mean: -7.19 ± 3.73). A single ablation zone ranging from 4.5 mm to 6 mm was used. In all eyes except for those with myopia over -15 D, emmetropia was a goal. Postoperatively patients used fluoromethalone drops for 1 month.

RESULTS: Treated eyes were divided into four groups based on preoperative myopia. Group 1 contained 15 eyes with myopia less than -3 D (93% were within ±1 D postoperatively). In Group 2 there were 53 eyes with preoperative myopia between -3.25 D and -6.00 D (64.1% were within ±1 D postoperatively). Group 3 consisted of 53 eyes with preoperative myopia between -6.25 D and -10.00 D (41.5% were within ±1 D postoperatively). Group 4 contained 36 eyes with myopia over -10.00 D (13.8% were within ±1 D of attempted correction and 11.1% were within ±1 D postoperatively).

CONCLUSIONS: Our study suggests that excimer laser photorefractive keratectomy using a 4.5 to 6.0 mm ablation zone effectively reduces myopia; however, predictability decreases as the attempted correction increases. [J Refract Surg. 1996;12:S255-S257.]
Comparison of Photorefractive Keratectomy for Myopia Using 5 mm and 6 mm Diameter Ablation Zones
Authors: Morris Antony T , Ring C Peter , Hadden O Bruce
Published: April 2021

ABSTRACT

BACKGROUND: We compared the 5 mm and 6 mm ablation zones of the Summit Omnimed in the treatment of myopia in 2 eyes of the same patient.

METHOD: One hundred and twenty-four consecutive patients with myopia less than 6 diopters (D) has one eye treated with a 5 mm ablation zone and the other eye with a 6 mm ablation zone. Minimum follow up was 6 months.

RESULTS: Follow-up was achieved in 101 patients of the total 124. In the 5 mm group 79% achieved 20/30 uncorrected visual acuity while 68% of the 6 mm group achieved 20/30 acuity. Ninetyseven percent of all eyes in both groups achieved 20/40. Some of the disparity between the 20/30 acuity in the two groups is that initial corrections with the 6 mm zones were conservative. Corneal haze was less in the 6 mm group; subjectively they had better night vision.

CONCLUSIONS: Both lasers with the different ablation zones gave reasonably predictable correction of myopia of up to -6 D. Overcorrection and corneal haze were less in the 6 mm group and night vision was subjectively better. [J Refract Surg. 1996;12: S275-S277.]
Excimer Laser Calibration System
Authors: Gottsch John D , Rencs Erik V , Cambier James L , Hall Deborah , Azar Dimitri T , Stark Walter J
Published: April 2021

ABSTRACT

BACKGROUND: Excimer laser photoablation for refractive and therapeutic keratectomies has been demonstrated to be feasible and practicable. However, corneal laser ablations are not without problems, including the delivery and maintenance of a homogeneous beam. We have developed an excimer laser calibration system capable of characterizing a laser ablation profile.

METHODS: Beam homogeneity is determined by the analysis of a polymethylmethacrylate (PMMA)based thin-film using video capture and image processing. The ablation profile is presented as a colorcoded map. Interpolation of excimer calibration system analysis provides a three-dimensional representation of elevation profiles that correlates with two-dimensional scanning profilometry. Excimer calibration analysis was performed before treating a monkey undergoing phototherapeutic keratectomy and two human subjects undergoing myopic spherocylindrical photorefractive keratectomy. Excimer calibration analysis was performed before and after laser refurbishing.

RESULTS: Laser ablation profiles in PMMA are resolved by the excimer calibration system to .006 µ??/pulse. Correlations with ablative patterns in a monkey cornea were demonstrated with preoperative and postoperative keratometry using corneal topography, and two human subjects using video-keratography. Excimer calibration analysis predicted a central-steep-island ablative pattern with the VISX Twenty/Twenty laser, which was confirmed by corneal topography immediately postoperatively and at 1 week after reepithelialization in the monkey. Predicted central steep islands in the two human subjects were confirmed by videokeratography at 1 week and at 1 month. Subsequent technical refurbishing of the laser resulted in a beam with an overall increased ablation rate measured as microns/pulse with a donut ablation profile. A patient treated after repair of the laser electrodes demonstrated no central island.

CONCLUSIONS: This excimer laser calibration system can precisely detect laser-beam ablation profiles. The calibration system correctly predicted central islands after excimer photoablation in a treated monkey cornea and in two treated human subjects. Detection of excimer-laser-beam ablation profiles may be useful for precise calibration of excimer lasers before human photorefractive and therapeutic surgery. [J Refract Surg. 1996;12:401-411.]
Photodocumentation of Corneal Scarring
Authors: Barr Joseph T , Gordon Mae O , Zadnik Karla , Pellican Kelly , Edrington Timothy B
Published: April 2021

ABSTRACT

PURPOSE: A standardized system for photodocumenting corneal scars and for evaluating these photographs does not exist and is essential for clinical research. To address this need, we developed a system for photographing and evaluating corneal scars.

METHODS: In the "Development Phase," we tested several procedures in small samples totaling 40 eyes of 20 keratoconus patients. In the "Test Phase," we used an independent sample of 150 eyes of 82 keratoconus patients. Fifty-nine of these 150 eyes had corneal scars, and 91 of the eyes did not as determined by the clinician.

RESULTS: The photography protocol requires four central parallelepiped and two whole cornea oblique photographs after pupil dilation. With the clinician as gold standard, this technique yielded sensitivity of 96% and specificity of 83%. Evaluation of the corneal photographs as to the presence or absence of corneal scarring was performed independently by two masked readers. Agreement between clinicians on the presence of corneal scarring was 0.99 (kappa); agreement between readers for the presence of scarring was 0.80 (kappa).

CONCLUSIONS: The corneal photography protocol we describe is recommended for use in clinical investigations of cicatrieizing corneal disease and appears robust enough to be used in multicenter studies. [J Refract Surg. 1996;12:492-500.]
Influence of Pregnancy and Labor on Outcome of Photorefractive Keratectomy
Authors: Hefetz Limor , Gershevich Alexander , Haviv David , Krakowski David , Eshkoly Moshe , Nemet Pinhas
Published: April 2021

ABSTRACT

Our study on 11 eyes indicates that pregnancy and labor probably do not influence the refractive results of photorefractive keratectomy. [J Refract Surg. 1996;12:512-513.]
Picosecond Laser In Situ Keratomileusis with a 1053-nm Nd:YLF Laser
Authors: Ito Mitsutoshi , Quantock Andrew J , Malhan Sameena , Schanzlin David J , Krueger Ronald R
Published: April 2021

ABSTRACT

BACKGROUND: Excimer laser in situ keratomileusis requires a microkeratome to generate an anterior corneal flap, plus an excimer laser to ablate the underlying stromal tissue. In this paper we introduce the concepts of laser flap formation and in situ keratomileusis using a picosecond laser.

METHODS: A neodymium-doped yttrium-lithiuxn-fluoride (Nd:YLF) laser with a plano-plano quartz applanation lens was used to generate various patterns of intrastromal photodisruption in human donor eyes to fashion anterior corneal flaps and generate intrastromal lenticules.

RESULTS: Smooth intrastromal dissections, 6 mm in diameter, were generated 160 Um below the corneal surface when the laser delivered pulses at 1 kHz with energies of either 40 uJ/pulse or 60 uJ/pulse, placed 20 urn apart in an expanding spiral. This enabled us to fashion anterior corneal flaps. The ease of the surgery and quality of the dissection corresponded well, and it was evident that both deteriorated noticeably when the laser pulses were separated by 25 µm or 30 µm, regardless of pulse energy. Using 40 uJ laser pulses placed 20 µm apart we also created a 5-mm diameter, 320 µm thick (130 µm - 450 µm deep) stromal lenticule below a corneal flap that was easily extracted when the flap was raised.

CONCLUSIONS: Anterior corneal flaps were easily fashioned using a NdtYLF laser. Picosecond laser in situ keratomileusis with a Nd:YLF laser could offer a favorable alternative to combined microkeratome/excimer laser in situ keratomileusis. [J Refract Surg 1996;12:721-728.]
Peripheral Melt of Flap after Laser in situ Keratomileusis
Authors: Castillo Alfredo , Diaz-Valle David , Gutierrez Angel R , Toledano Nicolás , Romero Francisco
Published: April 2021

ABSTRACT

BACKGROUND: Laser in situ keratomileusis (LASIK) is an effective procedure to correct myopia. It may have complications related to the flap, such as epithelial ingrowth and stromal melt.

METHODS: We report on a patient who developed extensive epithelial ingrowth and partial keratolysis of the flap following LASLK. This complication was treated by lifting the flap and removing the epithelium from within the interface.

RESULTS: Progressive keratolysis (stromal melt) can result in irregular astigmatism and loss of vision as well as photophobia and ciliary injection. The pathogenesis is not completely understood although the epithelial ingrowth in the interface is always present, and epithelial-stromal interaction with production of proteases may be involved.

CONCLUSION: Epithelial ingrowth may develop in the lamellar interface after LASLK and be associated with melting of the edge of the flap. This undesirable complication can be successfully managed with early surgical removal of the epithelium and proper attachment of the flap. [J Refract Surg 1998;14:61-63]
Continuous Non-contact Corneal Pachymetry with a High Speed Reflectometer
Authors: Böhnke Matthias , Chavanne Philippe , Gianotti Ronald , Salathé René Paul
Published: April 2021

ABSTRACT

PURPOSE: We developed an instrument that permits non-contact, continuous, high speed and high precision monitoring of corneal thickness and tested the stability and reproducibility of measurements made over extended time periods and under various conditions of low surface reflectivity encountered during protracted exposure of the unmoistened corneal surface to ambient air.

METHODS: The optical pachymeter (basic component of a broad-band, all-fiber Michelson interferometer) was used to monitor changes in the central corneal thickness of enucleated porcine eyes. Measurements were performed on three groups of eight eyes, each with different surface characteristics: intact epithelium, mechanically abraded epithelium, and 90 µm excimer laser keratectomy. Corneal thickness was monitored continuously with values recorded every 2 to 3 minutes for periods up to 1 hour in the absence of surface rinsing.

RESULTS: The thicknesses of all unmoistened corneas could be monitored with a precision of 1 µm (ascertained using a calibration glass plate and a living human cornea) over the entire observation period. Under ambient air conditions, deturgescence occurred in each case, and ranged from 1 to 5 µm/min. The rate of corneal thinning was fairly constant during the first 15 minutes of monitoring, but was nonlinear thereafter. Corneas with an intact epithelium had the lowest thinning rate with only 10% of the original thickness lost during the course of 1 hour. Deturgescence increased to 25% in corneas that had mechanical removal of the epithelium and to 28.5% in those that had an anterior excimer laser keratectomy, during a similar time-period.

CONCLUSION: With this new interferometric method, continuous, non-contact measurement of corneal thickness is possible to within a precision of 1 µta for periods up to 1 hour, even under the modified surface conditions after photoablative keratectomy. This device may be useful for on-line monitoring of ablation depths during such procedures. [J Refract Surg 1998;14:140-146]
Zonal Photorefractive Keratectomy for Presbyopia
Authors: Vinciguerra Paolo , Nizzola Guido Maria , Nizzola Francesco , Ascari Andrea , Azzolini Marco , Epstein Daniel
Published: April 2021

ABSTRACT

PURPOSE: We performed zonal excimer laser photorefractive keratectomy in three eyes of three presbyopic patients using a specially designed mask, with a minimum follow-up of 24 months.

METHODS: Two females (ages 59 and 48) and one male (age 55) were included in the study. The procedure was performed with a mask designed by one of the authors (GMN), applied to the AesculapMeditec Mel 60 excimer laser. The mask consists of a mobile diaphragm formed by two blunt blades. The aim in all the eyes was a presbyopic correction of 3.00 D.

RESULTS: After an initial regression of 1.00 D, the presbyopic correction remained stable during the 36-month follow-up. The patients read at least J3 at normal reading distance without correction. Since the ablated zone was only about 15% of the total area of a 3.0 mm pupil, all three patients were also able to read with their preoperative presbyopic correction (using the untreated 85% of the pupillary area).

CONCLUSION: Although only three eyes were treated with the zonal presbyopia mask presented here, the visual and refractive outcome appears promising in view of the relatively long follow-up time. [J Refract Surg 1998;14:S218-S221]