bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preliminary Evaluation of a Hydrogel Core-and-Skirt Keratoprosthesis in the Rabbit Cornea
Authors: Crawford Geoffrey J , Chirila Traian V , Vijayasekaran Sarojini , Dalton Paul D , Constable Ian J 
Published: April 2021

ABSTRACT
BACKGROUND: We developed a core-and-skirt keratoprosthesis, with both components made from poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels. The identical chemical nature of both spongy skirt and transparent core assures a permanent union between them. We have previously shown that PHEMA sponges, within a certain range of pore size, can support cellular invasion and neovascularization when implanted into the rabbit cornea. The present study is the first to evaluate the behavior of the whole prosthesis after implantation into the rabbit cornea.
METHODS: Hydrogel keratoprostheses were inserted intrastromally into the corneas of seven rabbits and histologically examined by light microscopy in five eyes enucleated at 8, 12, and 14 weeks.
RESULTS: None of the implants extruded over this period. Both clinical and histopathologic examination showed that the keratoprostheses were well tolerated by the host tissue. The porous skirt was fully integrated into the stroma by fibrovascular invasion, and no capsule formed around the implants. Stromal melting anterior to the implant occurred in two cases, but this did not affect the fixation of the keratoprostheses.
CONCLUSIONS: This study indicates that our keratoprosthesis can prevent extrusion in the short term when inserted into an intrastromal pocket of the rabbit eye. [J Refract Surg. 1996;12:526-529.]
Measurement of Irregular Astigmatism Using Semimeridian Data from Videokeratographs
Authors: Borderie Vincent M , Laroche Laurent 
Published: April 2021

ABSTRACT
BACKGROUND: Irregular astigmatism is one of the most troublesome side effects of corneal surgery. We attempted to quantify irregular astigmatism in a simple way, using semimeridian data from videokeratographs of corneas with different amounts of irregular astigmatism.
METHODS: We studied the corneal topography of 30 normal corneas to be used as controls, 30 corneas from patients after radial keratotomy, 30 corneas from patients after nonfreeze myopic keratomileusis, and 30 corneas with clinically apparent keratoconus. We developed two diagnostic formulas, a refractive power symmetry index and an angle symmetry index, using the absolute-scale, color-coded map, and semimeridian data from the EyeSys Corneal Analysis System, and used them to compare the four groups of corneas.
RESULTS: In the corneas with irregular astigmatism, values for the refractive power symmetry index and angle symmetry index were significantly higher than in the normal corneas. The refractive power symmetry index confidence interval set at 95% was 0.58 diopters (D) (range, 0.00 D to 0.58 D) in the control group. Using these limits, most values in the radial keratotomy, keratomileusis, and keratoconus groups were abnormal. Spectacle-corrected visual acuity correlated negatively with the refractive power symmetry index (rs=-0.58, /i<.001). The refractive power symmetry index sensitivity and specificity were respectively 97% and 66%. Spectacle-corrected visual acuity did not correlate with the angle symmetry index.
CONCLUSIONS: Semimeridian data from videokeratographs can be used to quantify irregular astigmatism. [J Refract Surg. 1996;12:595-600.]
Failure of Mechanical Epithelial Removal to Reverse Persistent Hyperopia After Photorefractive Keratectomy
Authors: Gauthier Charline A , Fagerholm Per , Epstein Daniel , Holden Brien A , Tengroth Bjorn , Hamberg-Nystrom Helene 
Published: April 2021

ABSTRACT
BACKGROUND: Residual hyperopic overcorrection after photorefractive keratectomy (PRK) using early algorithms is a rare but serious complication. Anecdotal evidence suggests that epithelial removal can stimulate epithelial hyperplasia, thereby reducing overcorrection. The aim of this study was to determine if epithelial removal effectively reduced hyperopia after PRK for myopia and, concurrently, to correlate the healing response with the refractive outcome.
METHODS: Enrolled were seven eyes of seven patients (mean age, 44 + 13 years) who had undergone PRK with a mean manifest refractive error of +2.21 ± 0.74 diopters (D). AU had undergone PRK an average of 24 + 9 months previously. Epithelial removal was performed over the excimer-treated zone with a surgical blade. Subjective refraction, epithelial thickness, corneal topography, and subepithelial haze were measured up to 1 year postoperatively.
RESULTS: Reduction in hyperopia between the baseline and 1-year visit was not statistically significant (mean difference, 0.55 D reduction; p=.102). That epithelial removal did not stimulate a woundhealing response is further supported by the absence of change in epithelial thickness over the first month and the small amounts of subepithelial haze. Central corneal power was reduced by a mean of 0.64 D after 1 month (p<.05).
CONCLUSIONS: Epithelial removal alone did not reduce the hyperopic overcorrection present after PRK, nor did it stimulate epithelial hyperplasia in the majority of these eyes. However, a trend toward improvement was noted with time was noted. [J Refract Surg. 1996;12:601-606.]
Bacterial Keratitis After Photorefractive Keratectomy
Authors: Amayem Ashraf , Ali Ahmed Tawfik , Waring George O , Ibrahim Osama 
Published: April 2021

ABSTRACT
Two patients who had excimer laser photorefractive keratectomy (PRK) for myopia developed bacterial keratitis, one from Staphylococcus epidermidis and the other with a negative culture. Both were treated with topical antimicrobial agents. One eye recovered an uncorrected visual acuity of 20/20. The other was left with a moderate subepithelial scar and an uncorrected visual acuity of 20/150. [J Refract Surg. 1996;12:642-644.]
Laser in situ Keratomileusis for Simple Myopic, Mixed, and Simple Hyperopic Astigmatism
Authors: Chayet Arturo S , Magallanes Roberto , Montes Miguel , Chavez Salvador , Robledo Nora 
Published: April 2021

ABSTRACT
PURPOSE: To summarize initial results of astigmatic laser in situ keratomileusis (LASIK) for 41 eyes of 26 patients using the EC-5000 Nidek system and assess its safety, efficacy and predictability.
METHODS: The EC-5000 Nidek excimer laser was used to correct simple myopic, mixed, and simple hyperopic astigmatism with manifest cylinder from 2.00 to 6.50 D. Ablation zone diameters were 6.5 mm (steep meridian ablation) to 7.5 mm (flat meridian ablation) with a repetition rate of 40-41 Hz. In eyes with simple myopic and mixed astigmatism, ablation was performed in both meridians; in eyes with simple hyperopic astigmatism, ablation was performed in the flat meridian alone. Followup was 3 months in all eyes.
RESULTS: Uncorrected visual acuity was 20/40 or better in 85% of the eyes. Uncorrected visual acuity was equal to the preoperative spectacle-corrected visual acuity in 63% of the eyes. Intended cylinder correction was within 1.00 D in 95% of eyes. No eyes lost lines of spectacle-corrected visual acuity.
CONCLUSION: LASIK using the EC-5000 excimer laser appears to be effective in the treatment of simple myopic, mixed, and simple hyperopic astigmatism, with favorable results as compared to those previously described for astigmatic keratotomy. [J Refract Surg 1998;14:S175-S176]
Angle-fixated Anterior Chamber Phakic Intraocular Lens for Myopia of -7 to -19 Diopters
Authors: Baikoff George , Arne Jean L , Bokobza Yves , Colin Joseph , George Jean L , Lagoutte Francoise , Lesure Pierre , Montard Michel , Saragoussi Jean J , Secheyron Patrick 
Published: April 2021

ABSTRACT
PURPOSE: To assess the safety and efficacy of a second generation, anterior chamber phakic intraocular lens (Baikoff Model ZB5M) in patients with high myopia.
METHODS: One hundred and twenty-one patients (134 eyes) with myopia of -7.00 to -18.80 D were implanted with the ZB5M lens and followed for 18 to 52 months; the number of eyes evaluated was: 6 months (104 eyes), 1 year (91 eyes), 18 months (78 eyes), 2 years (68 eyes), and 3 years (35 eyes).
RESULTS: Postoperative spherical equivalent refraction averaged -1.00 D and the error in refractive correction (achieved minus intended) averaged -0.40 D during the first 2 years, increasing -to -1.30 D refraction and -0.60 D error in refractive correction at 3 years. At 2 years, approximately 40% of eyes had a spherical equivalent refraction within ±0.50 D, and 65% within ±1.00 D. The uncorrected distance visual acuity was 0.048 at baseline and 0.5 at 3 years; near visual acuity was 0.21 at baseline and approximately 0.7 over the 3 years of follow-up. Spectacle-corrected distance visual acuity at baseline was 0.54; it improved to 0.7. Near visual acuity was 0.65 at baseline and it improved to approximately 0.75. Endothelial cell counts in the central and peripheral cornea were reduced by an average 3.3% at 6 months, declining an additional 1% to 2% over the remaining follow-up period. Regression analyses indicated that most of the endothelial cell loss was due to surgery. Additional complications included halos/glare in 37 of 133 eyes (27.8%) and iris retraction with pupillary ovalization in 30 of 133 eyes (22.6%). The intraocular lens was exchanged in four of 133 eyes (3.0%) and removed in three of 133 eyes (2.3%), the latter because of halos (one eye) and a flat anterior chamber with severe inflammation (two eyes).
CONCLUSIONS: Implantation of the Baikoff ZB5M lens in the anterior chamber of phakic eyes significantly reduced high myopia and produced a stable refractive outcome over the 3 years, accompanied by marked improvement in uncorrected distance visual acuity and minimal, non-progressive damage to the corneal endothelium. Frequent complications included pupillary ovalization and halos/glare. Improvements in accuracy of IOL power calculations are needed. [J Refract Surg 1998;14:282-293]
Mycobacterium Chelonae Keratitis Following Laser in situ Keratomileusis
Authors: Reviglio Victor , Rodriguez Mabel L , Picotti Gabriela S , Paradello Martin , Luna José D , Juárez Claudio P 
Published: April 2021

ABSTRACT
Corneal infection after laser in situ keratomileusis (LASIK) is rare. However, surgical trauma or breakdown of epithelium increases the risk of surface infection. We present the case of a 45 year old woman who developed keratitis due to Mycobacterium chelonae 1 month after LASIK with the Mini-Laser Sight 2000 excimer laser. After an initial improvement following antibiotic therapy the infection progressed until it was necessary to perform penetrating keratoplasty, with a successful result. [J Refract Surg 1998;14:357-3601
A Quantitative Corneal Topography Index for Detection of Keratoconus
Authors: Dastjerdi Mohammad H , Hashemi Hassan 
Published: April 2021

ABSTRACT
BACKGROUND: Detection of keratoconus has become a critical issue in patients who are potential candidates for refractive surgical procedures. In eyes with early stages of keratoconus, slit-lamp corneal changes are either absent or too subtle for detection, and keratometry may be normal. Videokeratography systems have greater sensitivity for detection of such cases, but interpretation of the topographic map is sometimes difficult, especially when pathologies with similar topographic patterns are suspected. We introduce an index using corneal topography for detection of keratoconus.
METHODS: From March 1994 to December 1995, a total of 513 unoperated eyes, with no pathology other than keratoconus, from 283 consecutive patients were categorized into three groups based on slit-lamp examination and corneal topographic findings. Those with clinically obvious keratoconus were placed in the first group (53 eyes [10.3%]), those with keratoconus suspect comprised the second group (17 eyes [3.3%]), and the third group was that of normal eyes (443 eyes [86.4%]). In all videokeratographs of these eyes, the highest rate of corneal power changes (in diopters per millimeter) away from the apex (the point of maximum power) to the periphery was measured along its semimeridian. This index, called the "highest rate of steepening (HRS)", was statistically analyzed in the three groups.
RESULTS: The mean ± SD of highest rate of steepening was 3.60 ± 1.70 D/mm (range 1.59 to 7.53 D/mm) in the clinically obvious keratoconus group, 1.59 ± 0.21 D/mm (range 1.35 to 1.98 D/mm) in the keratoconus suspect group, and 0.72 ± 0.31 D/mm (range 0.18 to 1.63 D/mm) in normal eyes. There was a highly statistically significant difference in the means of highest rate of steepening in the three groups (p < 0.0001). A small overlap in the highest rate of steepening ranges was shown among the three groups. Considering the first and second groups as cases of keratoconus, and 1.40 D/mm as the optimum cut-off value for highest rate of steepening, a sensitivity of 95.7% (67 out of 70 cases were detected), a specificity of 96.4% (16 false-positive cases), and an accuracy of 96.3% was obtained.
CONCLUSION: The highest rate of steepening may be a useful measure for keratoconus screening with videokeratography. Validation is needed to evaluate its accuracy. [J Refract Surg 1 998; 14:427-436]
Tenascin and Cytokines in Tear Fluid After Photorefractive Keratectomy
Authors: Vesaluoma Minna H , Tervo Timo T 
Published: April 2021

ABSTRACT
BACKGROUND: Basic knowledge of the substances involved in wound healing after photorefractive keratectomy (PRK) is essential for development of pharmacological intervention. We present preoperative and postoperative analysis of tear fluid extracellular matrix proteins and cytokines after PRK.
METHODS: Tear fluid samples from 70 patients (72 eyes) who had PRK (38 women and 32 men, mean age 31.5 yr) were studied. Samples from 18 patients (18 eyes) were analyzed in two different studies.
RESULTS: Mean preoperative tear fluid flow in the collection capillary (volume divided by tear collection time) varied from 4.5 to 22.5 µ?/min in five series of patients. It increased significantly during the first two postoperative days (range of means, 55.5 to 88.8 µ? min, ? < 0.01), and decreased to the preoperative level by day 7 (range of means, 9.7 to 18.2 µ?/min). The tenascin and cytokine release rates increased significantly during the first two days after PRK and returned to the preoperative level by day 7. Mean ± standard error for tenascin: day 0 (5.2 ±1.9 ng/min); day 2 (22.7 ±6.1 ng/min; p=0.02). Mean ± standard error for HGF: day 0 (3.2 ± 0.7 pg/min); day 1 (22.8 ± 4.2 pg/min; p=0.0003). Mean ± standard error for TGF-ßl: day 0 (63.3 ± 19.6 pg/min); days 1-2 (826.2 ± 253.7 pg/min; p=0.001). Mean ± standard error for VEGF: day 0 (166.0 ± 29.6 pg/min); days 1-2 (824.4 ± 165.1 pg/min; p=0.0007). Mean ± standard error for PDGF-BB: day 0 (0.42 ± 0.19 pg/min); day 2 (27.6 ± 5.8 pg/min; p=0.0000). Mean ± standard error for TNF-a: day 0 (9.5 ± 2.6 pg/min); day 2 (28.6 ± 5.9 pg/min; p=0.003). Excluding PDGF-BB, all substances studied were present in normal human tear fluid. PDGF-BB was present in only 17% of the preoperative samples.
CONCLUSION: Corneal wounding induces an increased release of several growth modulating cytokines which may be involved in healing processes. [J Refract Surg 1998;14:447-4541
Prospective Bilateral Study of Night Glare After Laser in situ Keratomileusis With Single Zone and Transition Zone Ablation
Authors: El Danasoury M Alaa 
Published: April 2021

ABSTRACT
PURPOSE: Evaluation of night glare after excimer laser in situ keratomileusis (LASIK) using two different ablation zone diameters.
METHODS: One hundred and twenty eyes of 60 consecutive myopic patients received LASIK with the Nidek EC-5000 excimer laser. Eyes were randomized so that every patient had a single ablation zone of 5.5 mm on one eye and an ablation zone of 5.5 mm with a transition zone of 1.0 mm diameter larger on the other eye. Night glare was measured by two methods; a spot light test and a subjective questionnaire.
RESULTS: At 6 months, 54 patients (90%) were examined; results of the spot light test showed that 40 patients (74.1%) perceived more glare with the eye with the single ablation zone; the subjective questionnaire indicated that 22 patients (40.7%) had more night glare with the eye with a single ablation zone compared to the other eye. The use of the transition zone increased the required total ablation depth by 20%.
CONCLUSION: The use of a peripheral transition 1.0 mm diameter larger than the ablation zone significantly decreased night glare after LASLK with slight increase in the required central ablation depth. [J Refract Surg 1998;14:512-516]
Lamellar Refractive Surgery with Scanned Intrastromal Picosecond and Femtosecond Laser Pulses in Animal Eyes
Authors: Kurtz Ron M , Horvath Christopher , Liu Hsiao-Hua , Krueger Ronald R , Juhasz Tibor 
Published: April 2021

ABSTRACTPURPOSE: To evaluate the use of scanned intrastromal picosecond and femtosecond laser pulses in lamellar refractive surgical procedures.METHODS: Intrastromal corneal photodisruption was performed in fresh porcine and primate cadaver eyes with a solid-state femtosecond laser. Laser pluses were focused 150 to 200 um below the epithelial surface and scanned in a spiral pattern to create a plane. A flap was made by scanning an arc pattern from the plane of the spiral to the surface of the cornea. Tissue plane separation was graded using a standard scale, while internal surfaces were analyzed by scanning electron microscopy. Comparison was made to a picosecond laser system using the same delivery system device. Creation of a stromal lenticule for in situ keratomileusis was also demonstrated and compared with both laser systems.RESULTS: For femtosecond pulses, tissue separation was achieved best with pulse energies from 4 to 8 µl and spot separations from 10-15 µm. Picosecond pulses accomplished less complete separations with pulse energies of 25 uJ and spot separations from 10 to 20 µp?. Surface quality corresponded to dissection results, with high-grade dissections resulting in a smooth surface appearance, versus a more irregular surface for low-grade dissections. Although high-grade dissections could be created with picosecond pulses (with optimal parameters) in ex vivo porcine eyes, only femtosecond parameters produced similar results in ex vivo primate eyes.CONCLUSION: In contrast to previous attempts using picosecond lasers which require additional mechanical dissection, high precision lamellar refractive surgery may be practical with femtosecond laser pulses. [J Refract Surg 1998;14:541-548]
Perioperative Microbiologic Profile of the Conjunctiva in Photorefractive Keratectomy
Authors: Barequet Irina S , Jabbur Nada S , Barron Yolanda , Osterhout Gerard J , O'Brien Terrence R 
Published: April 2021

ABSTRACT
PURPOSE: Therapeutic soft contact lenses are used commonly as an adjunctive treatment after photorefractive keratectomy (PRK) to decrease postoperative pain caused by the movement of lids over the corneal epithelial defect and to facilitate epithelial healing. We assessed the microbiological profile of the conjunctiva of patients undergoing PRK for myopia, before and after the concurrent use of a therapeutic soft contact lens, and compared the effect on ocular bacterial colonization of prophylactic administration of topical tobramycin 0.3% versus ofloxacin 0.3%.
METHODS: Forty-three consecutive eyes from 37 patients underwent PRK for myopia or myopic astigmatism. Eyes were assigned randomly to prophylactic antibacterial treatment with either topical ofloxacin 0.3% or tobramycin 0.3%, applied prior to surgery and three times daily after surgery until therapeutic soft contact lens removal. Material from the conjunctival sac was obtained for bacteriologic cultures prior to surgery. Clinical evaluation of all eyes was conducted prospectively. Three days after PRK, the therapeutic soft contact lenses were removed and cultured. Cultures from the conjunctival sac were then repeated.
RESULTS: No statistically significant differences were observed in culture positivity between the two groups of eyes, in spite of some positive preoperative and postoperative cultures. Only one out of 43 eyes (assigned to the ofloxacin group) developed a peripheral corneal infiltrate. The corneal infiltrate healed completely without sequelae using antibiotic and corticosteroid therapy.
CONCLUSIONS: The use of therapeutic soft contact lenses after PRK with either topical tobramycin 0.3% or ofloxacin 0.3% were well tolerated. However, perioperative positive conjunctival cultures were relatively frequent and prophylactic antibiotics should be used in the setting of an epithelial defect and therapeutic soft contact lens following PRK. [J Refract Surg 2001;17:55-62]
Laser in situ Keratomileusis for the Correction of Hyperopia From +0.50 to +11.50 Diopters With the Keracor 117C Laser
Authors: Tabbara Khalid F , El-Sheikh Hisham F , Islam S M Monowarul 
Published: April 2021

ABSTRACT
PURPOSE: To evaluate excimer laser in situ keratomileusis (LASIK) for the correction of hyperopia.
METHODS: We reviewed retrospectively the medical records of 46 patients treated with LASIK for hyperopia. All patients had a complete ophthalmologic evaluation. The corneal bed was ablated using the Bausch & Lomb Chiron Keracor 117C excimer laser to create a paracentral annular ablation under a nasally hinged 160-µm corneal flap with the Chiron Automatic Corneal Shaper microkeratome. Follow-up was a minimum of 6 months.
RESULTS: Eighty eyes of 46 patients (23 males and 23 females) were included. Age ranged from 18 to 65 years (mean, 42 yr). The range of preoperative spherical equivalent refraction was +0.50 to +11.50 D (mean, +3.40 D). Mean postoperative spherical equivalent refraction at 6 months was +0.26 D. Six months after surgery, 35 eyes (44%) achieved uncorrected visual acuity of 20/20 or better and 78 eyes (97.5%) achieved 20/40 or better. Forty-six eyes (58%) had a postoperative spherical equivalent refraction within ±0.50 D of attempted correction, and 67 eyes (84%) were within ±1.00 D of attempted correction. When using the Bausch & Lomb Chiron Keracor 117C excimer laser to correct hyperopia, eyes with a spherical equivalent refraction less +2.00 D should be overcorrected by 25%, +2.00 to +4.00 D by 30%, and over +4.00 by 40%. The positive cylinder should, be overcorrected by 10%.
CONCLUSIONS: LASBS was safe and effective in the treatment of hyperopia from +0.50 to +11.50 D. Regression following LASIK for hyperopia remains a problem. A special nomogram was required to achieve results comparable with those for myopia. [J Refract Surg 2001;17:123-128]
Prevention of Corneal Ectasia in Laser in situ Keratomileusis
Authors: Vinciguerra Paolo , Camesasca Fabrizio I 
Published: April 2021

ABSTRACT
PURPOSE: Ectasia after laser in situ keratomileusis (IASIK) is a rare but serious complication. Prevention includes proper patient selection with detection of those at particular risk. Causes of ectasia include predisposition, excessive ablation with less than 250 µt? of residual stromal bed, thicker than normal flap, irregular corneal thickness, and different ablation rates.
METHODS: We evaluated corneal curvature patterns and their relationship to corneal topography and pachymetry maps.
RESULTS: Corneal topography (axial, tangential, and altimetric) and pachymetry map characteristics of normally astigmatic corneas, keratoconus, false-positive and false-negative cases, as well as contact lens-induced warpage are discussed.
CONCLUSIONS: Preoperative pachymetry maps for LASIK surgery allow accurate case selection through detection of borderline cases, and provide important documentation of preoperative status, as well as useful information for improving surgical strategy. Another important parameter is the asphericity index. [J Refract Surg 2001;17(suppl): S187-S189]