bluuebunny/crossref_metadata_2025_split huggingface dataset:
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]
Comparison of Keratometry and Videokeratography After Penetrating Keratoplasty
Authors: Karabatsas Constantinos H , Cook Stuart D , Powell Kate , Sparrow John M 
Published: April 2021

ABSTRACT
BACKGROUND: As new methods for corneal curvature measurement have evolved, users of videokeratscopes need to know the practical limitations of these instruments. We assessed agreement between keratometry and videokeratography in measuring highly astigmatic corneas.
METHODS: Two independent examiners made three keratometric and videokeratographic measurements on each of 33 corneas after penetrating keratoplasty. The non-orthogonal keratometric readings obtained with a Zeiss 10 SIVO keratometer (Carl Zeiss Ltd.) were compared to the non-orthogonal si m K readings (maxK, minK) calculated by the algorithms of a TMS-I videokeratoscope (Tomey). Measurement agreement was evaluated for steep and flat meridian power and location, and astigmatism magnitude (D).
RESULTS: A systematic bias of the TMS-I in measuring steeper than keratometry for the steep meridian was demonstrated (95% confidence interval: -0.34 to -1.20 D). The limits of agreement (d-2SD to d+2SD) between the two instruments were found to be unacceptable for clinical purposes in measuring steep meridian power (-3.17 to +1.63 D), flat meridian power (-4.92 to +4.48 D) and astigmatism magnitude (-5.84 to +4.87 D). Clinically acceptable differences were observed in identification of steep and flat meridian location.
CONCLUSIONS: The Zeiss 10 SL/O keratometer and the TMS-I videokeratoscope showed poor measurement agreement for irregular corneal surfaces, despite the good correlation previously shown between keratometry and videokeratography in calibrated spheres and regular corneas. The TMS-I showed a systematic bias, measuring a greater power in the steeper meridian than the Zeiss 10 SL/O keratometer. It is suggested that the two instruments cannot be used interchangeably in comparing the curvature of corneas after penetrating keratoplasty. [J Refract Surg 1998;14:420-426]
Corneal Wound Healing After Laser in situ Keratomileusis in Rabbits
Authors: Pérez-Santonja Juan J , Linna Tuuli U , Tervo Kaarina M , Sakla Hani F , Sanz Jorge L Alió Y , Tervo Timo M 
Published: April 2021

ABSTRACT
BACKGROUND: The aim of this study was to characterize the cell biology of wound healing in rabbit corneas subjected to laser in situ keratomileusis (LASIK).
METHODS: Rabbit corneas underwent LASBK with various multizone photoablations or only a lamellar keratotomy followed by repositioning of the flap. We looked for indications for an active wound healing process. Immunohistoehemistry for the extradomain A cellular fibronectin (EDA-cFn) or tenascin (Tn) and routine histology were examined.
RESULTS: Four days after LASEK or lamellar keratotomy followed by repositioning of the flap, epithelial plugs and prominent keratocytes as well as Tn and EDA-cFn immunor eactions - indicative of a wound-healing process- appeared in the wound margins. Epithelial plugs were less conspicous, and prominent, presumably activated, keratocytes were no longer identified at the wound margin at 2.5 and 5 months after wounding. However, EDA-cFn and Tn immunoreactivities could still be observed. Only the stromal cells located in the periphery of the flap and in relatively close contact with the epithelium were surrounded by scar tissue expressing immunoreactivity for EDA-cFn or Tn. The central corneal stroma was devoid of scar tissue.
CONCLUSION: Results indicate that the wound healing reaction after LASIK takes place only at the periphery of the microkeratome wound, leaving the central optical zone clear. [J Refract Surg 1998;14:602-609]
Corneal Hydration Monitored by Laser-induced Breakdown Spectroscopy
Authors: Pallikaris Ioannis G , Ginis Harilaos S , Kounis Georgios A , Anglos Demetrios , Papazoglou Theodore G , Naoumidis Leonidas P 
Published: April 2021

ABSTRACT
BACKGROUND: Corneal hydration is an important factor in laser corneal ablation. In photorefractive keratectomy (PRK), corneal ablation rate and final ablation surface quality are strongly dependent on corneal hydration. We used, a spectroscopic technique for monitoring corneal hydration during PRK.
METHODS: Hydroxyethylmethacrylate (HEMA) was employed for corneal hydration modeling. Hydrated HEMA samples were irradiated with a pulsed Nd:YAG laser (1064 run, 10 mJ/pulse, pulse duration 15 nsec). Successive emission spectra corresponding to different degrees of hydration were recorded on a gated optical multichannel analyzer. The weight of the sample and hence its water content was monitored during the entire procedure with a sensitive balance. One rabbit and one human cornea were used to demonstrate the spectral analogy between the model and corneal tissue.
RESULTS: The most noticeable dependence on water content of the substrate was that of atomic emission lines of Ca at 393 nm and 396 nm.
CONCLUSION: Plasma emission spectra exhibited significant dependence on sample hydration. This dependence can be used for estimation of water content of irradiated model material and real cornea. [J Refract Surg 1998;14:655-660]
Change in Intraocular Pressure in Myopic Eyes Measured With Contact and Non-contact Tonometers After Laser in situ Keratomileusis
Authors: El Danasoury M Alaa , El Maghraby Akef , Coorpender Steven J 
Published: April 2021

ABSTRACT
PURPOSE: To study the change in the intraocular pressure (IOP) after laser in situ keratomileusis (LASIK) for correction of myopia.
METHODS: One hundred twenty consecutive myopic eyes (60 patients) were included in a prospective study. All eyes received LASIK with the Nidek EC-5000 excimer laser and the Chiron Automated Corneal Shaper. Baseline refraction, keratometry, pachymetry, ablation depth, and IOP measured by Goldmann applanation tonometry and non-contact air puff tonometry were correlated with the IOP change after surgery. Sixty healthy eyes of 30 subjects served as controls.
RESULTS: At 6 months, 108 eyes (90%) were examined. Compared to preoperative values, IOP decreased in 103 eyes (95.4%) when measured with applanation tonometry; it decreased in all eyes when measured with air puff tonometry. Mean change in IOP was -4.3 ± 2.1 mmHg (range, -10.0 to +1.0 mmHg) with the applanation and -6.1 ± 2.3 mmHg (range, -12.0 to -1.0 mmHg) with air puff tonometry. The IOP change measured with either instrument correlated significantly with the baseline IOP (P < .001) and the ablation depth (air puff, P < .001, applanation; P = .006).
CONCLUSION: Intraocular pressure decreased significantly after LASEK when measured with either Goldmann (mean 4.3 mmHg) or air puff (mean 6.1 mmHg) tonometers. This decrease may delay the diagnosis or affect the management of future glaucoma that may develop in a myopic eye that received LASEK. [J Refract Surg 2001;17: 97-104]