bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correction of Hyperopia Induced by Photorefractive Keratectomy Using Non-contact Ho:YAG Laser Thermal Keratoplasty
Authors: Alió Jorge L , Ismail Mahmoud M , Artola Alberto , Santonja J J Pérez 
Published: April 2021

ABSTRACT
PURPOSE: To evaluate the safety and effectiveness of non-contact holmium:YAG laser thermal keratoplasty in correcting hyperopia induced by photorefractive keratectomy (PRK).
METHODS: Non-contact holmium:YAG laser thermal keratoplasty was applied to 14 eyes with significant hyperopia induced by PRK. The mean spherical equivalent refraction before holmium:YAG laser thermal keratoplasty was +4.20 ± 1.80 diopters (D) (range, +1.75 to +6.25 D). The results were evaluated 12 months after holmium:YAG laser thermal keratoplasty.
RESULTS: No sight-threatening complications occurred. Recovery of spectacle-corrected visual acuity took from 2 to 6 weeks. The immediate significant myopic shift that developed in all eyes gradually receded over 6 to 8 weeks. All eyes were relatively stable after 9 months. At 12 months, there was no statistically significant difference (p < .005) between the mean preoperative spectacle-corrected visual acuity (0.71 ± 0.12) and the mean postoperative uncorrected visual acuity (0.65 ± 0.28). At 12 months there was a mean increase of 4.60 ± 1.20 D in central keratometric power. Total regression did not occur in any eye.
CONCLUSION: Non-contact holmium:YAG laser thermal keratoplasty offers a safe and effective alternative to correct PRK-induced hyperopia. [J Refract Surg 1997;13:13-16]
Laser In Situ Keratomileusis for Astigmatism and Myopia after Penetrating Keratoplasty
Authors: Arenas Eduardo , Maglione Antonio 
Published: April 2021

ABSTRACT
BACKGROUND: After penetrating keratoplasty, many patients have high ametropia, which is difficult to correct with contact lenses. We used excimer laser in situ keratomileusis (LASIK) on four eyes of four consecutive patients that had previous penetrating keratoplasty in an attempt to correct myopia and astigmatism.
METHODS: We used an automated microkeratome to make a lamellar flap and a Chiron Technolas 193-nm argon fluoride excimer laser. The laser was programmed for the desired myopic and astigmatic correction and a multizone ablation was applied to the central stroma. The corneal flap was placed back into position without sutures.
RESULTS: After surgery, all corneas remained clear with no dislocation of the flap, and the edge of the flap was difficult to visualize after a few days. The average preoperative spherical equivalent was -10.75 diopters (D) (range -5.00 to -14.25 D) which decreased to an average -2.37 D (range -0. 75 to -5.00 D) at a mean follow-up of 7 months (range 6 to 10.5 mos). The average preoperative astigmatism was -2.87 D (range -1.00 to -5.00 D) which changed to an average of -3.50 D. Uncorrected visual acuity was improved and spectacle-corrected visual acuity was preserved without changes.
CONCLUSION: LASIK can effectively reduce myopia after penetrating keratoplasty. [J Refract Surg 1997;13:27-32]
Photoastigmatic Refractive Keratectomy for Compound Myopic Astigmatism with a Nidek Laser
Authors: Goggin Michael J , Kenna Paul F , Lavery Frank L 
Published: April 2021

ABSTRACT
BACKGROUND: With advances in the delivery of excimer laser energy to the cornea, spherocylindrical ablations are now possible. The refractive and visual outcome of eyes undergoing photoastigmatic refractive keratectomy with a minimum of 12 months follow-up are presented.
METHODS: A retrospective analysis of 160 consecutive eyes that underwent photoastigmatic refractive keratectomy using the Nidek EC5000 excimer laser was undertaken. One year follow-up data were available on 89 eyes. Vector analysis of the change in cylindrical error, by the Alpins method, was performed. Before surgery, the mean spherical equivalent refraction was -5.68 diopters (D) (SD 2.67 D) with a mean cylinder power of -1.40 D (SD 0.75).
RESULTS: At 1 year after surgery, the mean spherical equivalent was -0.44 D (SD 0.87). Seventy-one eyes (79.8%) had a spherical equivalent within 1.00 D of the target refraction and 79 eyes (89%) achieved 6/12 or better, unaided. Four of 89 eyes (4.5%) lost more than two lines of spectacle-corrected visual acuity with 9 eyes (10%) gaining Snellen acuity, comparing preoperative spectacle-corrected acuity with postoperative uncorrected visual acuity. The mean coefficient of adjustment (targeted induced astigmatism vector magnitude divided by surgically induced astigmatism vector magnitude) was 1.11 (SD 1.33), indicating undercorrection of the cylinder. The mean angle of error was 0.73° (± 10.91).
CONCLUSIONS: Refractive visual acuity outcome after photoastigmatic refractive keratectomy was good. Current algorithms undercorrect the cylinder power, but are adequately aligned. Algorithms for toric ablations in the Nidek EC5000 need to be improved. [J Refract Surg 1997;13:162-166]
Organization of Collagen in the Lyophilized Cornea
Authors: Quantock Andrew J , Verity Steven M , Schanzlin David J 
Published: April 2021

ABSTRACT
PURPOSE: To investigate the organization of collagen fibrils in the lyophilized cornea.
METHODS: Freshly harvested porcine corneas (n=10) were lyophilized and examined by synchrotron x-ray diffraction and transmission electron microscopy.
RESULTS: Collagen fibrils are highly compacted in lyophilized corneas. They become more widely spaced when the tissue is rehydrated, however, the distribution of imbibed water throughout the stroma is not necessarily homogeneous within an individual cornea, nor is it always similar in specimens that have been rehydrated to similar levels. In lyophilized corneas, the mean center-to-center interfibrilar spacing of the regularly arranged collagen reaches levels found in freshly thawed porcine corneas (between 74% and 78% water by weight) when between 74.3% and 81.6% of the rehydrated lyophilized cornea's weight is water.
CONCLUSION: Regularly arranged collagen fibrils are able to reapproximate their original spacings if lyophilized corneal tissue is rehydrated, although the manner in which imbibed water is distributed is somewhat unpredictable. [J Refract Surg 1997;13:167-170]
Improved Technique of Circular Keratotomy for the Correction of Corneal Astigmatism
Authors: Krumeich Jorg H , Knülle A , Daniel J 
Published: April 2021

ABSTRACT
BACKGROUND: Based on Gaues' law governing the comparison of hyperbaric pressure in the eye and atmospheric pressure, the authors present a procedure to correct astigmatism. The present paper describes an improvement of a technique for circular keratotomy that was published previously.
METHODS: We present data on a consecutive series of 32 eyes with a mean corneal astigmatism of 4.66 diopters (D) (range -2.25 to -6.00 D) with a variety of clinical diagnoses. The astigmatic cornea was trephined with a diameter of 7 mm and a depth of 300 µm. After deepening of the trephination with a diamond knife to 550 µm over the steeper semimeridians, the intraocular pressure created a rounding of the cornea. The amount of astigmatic correction and extent of deepening were controlled intraoperatively with a keratoscope. No sutures were placed.
RESULTS: In 32 consecutive eyes, corrections were between 50 and 90% of the initial cylindrical values after 1 week to 1 month. In 29 eyes (91%), the results obtained remained stable during a 1-year follow-up; in two eyes (6%), the 1-month results worsened by more than 1.00 D and in one eye (3%), results improved by more than 1.00 D. There were no complications during or after surgery. Wound gaping resulting in epithelial plugs did not occur. No patient lost one or more lines of spectaclecorrected visual acuity, but 13 eyes (40%) gained one or more lines.
CONCLUSION: The technique of correcting corneal astigmatism by trephining to a depth of 300 µm., with deepening of the wound to 550 µm along the steep meridian and using no sutures can correct up to 10.00 D of astigmatism with reasonable stability. [J Refract Surg 1997;13:255-262]
Permalens Hydrogel Intracorneal Lenses for Spherical Ametropia
Authors: Barraquer José I , Gomez Maria Laura 
Published: April 2021

ABSTRACT
PURPOSE: To assess the efficacy, stability, and safety of Permalens hydrogel intracorneal lenses for the correction of spherical ametropia 6 years after implantation.
METHODS: Implantation of intracorneal hydrogel lenses was performed by the same surgeon (JIBM) in five aphakic and five high myopic eyes. The lens closest to corneal vertex refraction was used. Refractive outcomes, keratometry, keratography, endothelial cell count, and corneal topography were studied.
RESULTS: Corneal tolerance to the hydrogel implants was maintained throughout for ß years with no alteration in endothelial cell count. All myopic eyes showed regression of achieved correction. The aphakic eyes showed no statistically significant difference between the results at 1 month and those obtained at 1 and 6 years.
CONCLUSIONS: Hyrdogei intracorneal lenses are well tolerated and the refractive results are stable in aphakic patients. They may be considered when intraocular lenses cannot be placed in aphakic patients, but are not now in clinical use. [J Refract Surg 1997;13:342-348]
Regression of Myopia Induced by Pregnancy after Photorefractive Keratectomy
Authors: Sharif Khaled 
Published: April 2021

ABSTRACT
BACKGROUND: We evaluated refractive corneal changes that occurred in women who become pregnant after undergoing excimer laser photorefractive keratectomy (PRK) for the treatment of myopia.
METHODS: Refractive results of 18 eyes of nine women who underwent PRK and became pregnant during the follow-up period were reviewed. All eyes were followed for a least 12 months after PRK. Subjective refraction, slit-lamp microscopy, and intraocular pressure were measured at each followup examination.
RESULTS: Twelve of 18 eyes (66%) had myopic regression during the follow-up period. The regression was associated with 1+ to 2+ corneal haze in 10 of these 12 eyes (83.3%). The three women (6 eyes) who had stable refractions after PRK became pregnant at least 5 months postoperatively. The corneal haze and the associated myopic regression improved in 50% of the eyes after delivery.
CONCLUSION: Pregnancy seems to induce effects on corneal wound healing following PRK. [J Refract Surg 1997;13(suppl):S445-S446]
Epikeratoplasty for Keratoconus Using Manually Dissected Fresh Lenticules: 4-year Follow-up
Authors: Vajpayee Rasik B , Sharma Namrata 
Published: April 2021

ABSTRACT
BACKGROUND: Epikeratoplasty for keratoconus, in the absence of apical scarring, aims at reducing high irregular myopic astigmatism and provides an ectatic cornea with mechanical support.
METHODS: We performed epikeratoplasty on 11 keratoconic corneas using fresh or McCareyKaufman preserved, manually dissected donor lenticules. A disparity of 0.5 nun was maintained between the host and the donor. Patients with keratoconus having a preoperative spectaclecorrected visual acuity of less than 6/60 and intolerance to contact lens wear were included in this prospective study. Spectacle-corrected visual acuity, keratometry, and refraction were analyzed over a 4-year follow-up period.
RESULTS: Four year follow-up was completed on 10 eyes. Of these, 80% achieved a postoperative spectacle-corrected visual acuity of 6/12 or better. Average postoperative keratometry was 45.79 ± 2.07 D and a decrease of 4.60 ± 0.09 D was observed in refractive cylinder. Spherical equivalent showed a significant decrease in myopia of -4.35 ± 0.26 D. Mean time to stabilization was 8 ± 2.3 weeks. Epithelial defects occurred in three eyes; two were successfully treated by patching. One lenticule was removed due to graft infection following a persistent epithelial defect.
CONCLUSION; Epikeratoplasty for keratoconus is a useful procedure with good long-term visual acuity results and an early stabilizing period. [J Refract Surg 1997;13:659-662]
Prospective Randomized Study of Corneal Aberrations 1 Year After Radial Keratotomy or Photorefractive Keratectomy
Authors: Hjortdal Jesper Ø , Olsen Hanne , Ehlers Niels 
Published: April 2021

ABSTRACT
PURPOSE: To evaluate the optical properties of the cornea 1 year after either radial keratotomy (RK) or photorefractive keratectomy (PRK) in a randomized group of patients with low myopia.
METHODS: Ninety-six patients with myopia between -0.75 and -5.00 D were randomized to either radial keratotomy (n=46) or photorefractive keratectomy (n=50). Topography maps were obtained 1 year after surgery and analyzed by computation of total corneal wavefront aberration and Zernike polynomial coefficients for pupil sizes of 2, 4, and 6 mm. The 4-mm pupil size was used for optimization of the model.
RESULTS: The total corneal wavefront aberrations after RK and PRK were similar and not statistically different. Wavefront aberrations arising from astigmatism or defocus accounted for approximately 70% of the total wavefront error at all pupil sizes in both groups. All types of aberrations, and in particular spherical aberration, increased significantly with increasing pupil size. Higher-order wavefront aberrations were almost twice as high after RK than after PRK at pupil sizes of 4 and 6 mm. Spherical aberration and coma were slightly higher after PRK than after RK.
CONCLUSIONS: Pupil size had a major effect on corneal aberrations after RK and PRK. The most important aberrations were sphero-cylindrical, in which eyes became significantly more myopic with increasing pupil size. The image forming properties of the cornea are better after PRK compared with RK due to the lesser amount of higher-order aberrations. [J Refract Surg 2002;18:23-29]
Results of Photorefractive Keratectomy for Hyperopia Using the VISX Star Excimer Laser System
Authors: Stevens Julian D , Ficker Linda A 
Published: April 2021

ARSTRACT
PURPOSE: To evaluate safety, efficacy, and predictability of photorefractive keratectomy (PRK) for hyperopic astigmatism of +1.75 to +5.00 D manifest refractive sphere and up to -2.50 D manifest refractive astigmatism using the VISX Star excimer laser system, version 2.5 software.
METHODS: Treatment was performed on 32 eyes of 21 patients. Eighteen of 21 patients were 45 years of age or older. Manifest and cycloplegic refraction together with Pelli-Robson contrast sensitivity assessment was performed prior to surgery and I1 3, 6, 12, and 24 months after treatment.
RESULTS: Twenty-seven of 32 surgical procedures were reviewed 1 year after treatment (84%). Corneal epithelial healing was complete between day 4 and 10. Twelve months after treatment, 25 of 27 eyes (93%) achieved 20/40 or better uncorrected visual acuity and 19 eyes (70%) achieved 20/20. No patient lost two or more lines of Snellen visual acuity assessed 6 months and later after treatment. The mean spherical equivalent refraction was reduced from +2.90 at baseline to +0.10 D at 1 year and +0.40 D at 2 years; 65% of eyes had a refraction within ±0.50 D. Four patients had further treatment by laser in situ keratomileusis for undercorrection in three eyes and overcorrection in one eye. PelliRobson contrast acuity was significantly reduced 12 months after treatment from a mean 1.72 before to 1.66 after PRK (P=.02, t-test).
CONCLUSIONS: PRK for hyperopia using the VISX Star excimer laser system was effective in the treatment of hyperopic astigmatism. Although no patient lost two or more lines of high contrast best spectacle-corrected Snellen visual acuity 1 year after treatment, there was a significant decrease in Pelli-Robson contrast acuity. [J Refract Surg 2002;18:30-36]
Risk Factors for Insufficient Fixation of Microkeratome During Laser in situ Keratomileusis
Authors: Asano-Kato Naoko , Toda Ikuko , Hori-Komai Yoshiko , Takano Yoji , Tsubota Kazuo 
Published: April 2021

ABSTRACT
PURPOSE: To investigate the potential risk factors leading to insufficient fixation of a microkeratome during laser in situ keratomileusis (LASIK), especially in Asian eyes.
METHODS: We performed a retrospective analysis of 1809 eyes of 972 patients that underwent LASlK. Profiles of patients (age, sex, past medical history, width of palpebral fissure, corneal power, and postoperative clinical course) whose operations were discontinued due to insufficient fixation were compared to all LASIK patients.
RESULTS: Insufficient fixation was observed in 18 eyes of 16 patients. Those patients were significantly younger (26.1 ± 5.5 yr) compared to all patients (32.3 ± 8.6 yr). Mean keratometric power was 42.40 ± 1.37 D in patients with insufficient fixation and 43.60 ± 1.40 D in all patients (P<.001). Maximum width of palpebral fissure with eyes wide open was 0.96 ± 0.20 mm in patients with insufficient fixation, and 1.10 ± 0.19 mm in all patients (P=.0015). These patients subsequently underwent LASlK utilizing combinations of cooling, frequent corticosteroid instillation for several hours, and lateral canthotomy.
CONCLUSION: Narrow palpebral fissures commonly found in Asian populations might be a risk factor for insufficient fixation of a microkeratome in LASIK, especially in young patients with flat corneas. [J Refract Surg 2002;18:47-50]
Diurnal Variation of Human Corneal Curvature in Young Adults
Authors: Handa Tomoya , Mukuno Kazuo , Niida Takahiro , Uozato Hiroshi , Tanaka Shunichi , Shimizu Kimiya 
Published: April 2021

ABSTRACT
PURPOSE: To elucidate the diurnal variation of human corneal curvature with regard to gender and menstrual cycle.
METHODS: Changes in corneal curvature and intraocular pressure (IOP) were measured over 24 hours in 14 young adults using corneal topography and a non-contact tonometer. In study 1, seven males and seven females (after menses) were measured. In study 2, four females out of the seven volunteers who participated in study 1 were measured again during menses.
RESULTS: The females after menses showed a remarkable diurnal variation throughout 24 hours. A significant difference between the light-wake periods and dark-sleep periods of 0.83 ± 0.15 D was found (P<.01). Corneal curvature was significantly flatter during menses than after menses in the light-wake period (P<05). In the males, no significant diurnal change (0.21 ± 0.12 D) was measured in corneal curvature.
CONCLUSIONS: Diurnal variation of corneal curvature was significant, approximately 0.83 D in young females after menses, and corneal curvature became flatter during menses in young females. Diurnal variation of corneal curvature is an important parameter for planning refractive surgery and contact lens wear. [J Refract Surg 2002;18:58-62]
Evaluation of Tear Film Following Intacs for Myopia
Authors: Kessler Daniel , El-Shiaty Ayman F , Wachler Brian S Boxer 
Published: April 2021

ABSTRACT
PURPOSE: To evaluate the effect of intrastromal corneal ring segments (lntacs, Keravision) placement on the tear film quality as a measure of dry eye status.
METHODS: Seventeen eyes of ten patients underwent lntacs placement for the correction of myopia with spherical equivalent refractions ranging from -1.75 to -3.25 D (mean, -2.43 ± 0.56 D). Dry eye grade values were measured preoperatively and at 1 day, 1 week, and 1 month postoperatively using the Ko wa -DR-I interferometer.
RESULTS: Preoperatively, the 17 eyes had a mean dry eye grade of 2.18 ? 0.39 (range, 2 to 3). One day postoperatively, the 14 eyes measured had a mean dry eye grade of 2.64 ± 0.63 (range, 2 to 4; P = .03). At 1 week the 17 eyes had a mean dry eye grade of 2.41 ± 0.71 (range, 2 to 4; P = .25) and at 1 month, 2.18 ± 0.39 (range, 2 to 3; P = .75).
CONCLUSIONS: There was transient dry eye following lntacs placement, but the tear film quality was restored within 1 week of surgery. [J Refract Surg 2002;18:127-129]
Effect of Topical Diclofenac and Ketorolac on Patient Discomfort and Corneal Sensitivity
Authors: Narváez Julio , Kroll Peter , Guzek James P 
Published: April 2021

ABSTRACT
PURPOSE: To determine if at clinical dosages, the topical nonsteroidal anti-inflammatory drugs diclofenac and ketorolac decrease corneal sensitivity, and if there is a difference in discomfort on instillation.
METHODS: In a double-masked study, 30 patients were randomized to receive two of three topical drops, Endosol, diclofenac sodium, and ketorolac tromethamine. A microaesthesiometer was used to evaluate corneal sensation. Baseline corneal sensitivity was obtained on each patient. Corneal sensory thresholds were remeasured at 7 and 15 minutes following eyedrop application. Patients also completed a questionnaire that graded the burning caused by the medications.
RESULTS: No significant decrease in corneal sensory thresholds was found with diclofenac or ketorolac compared with control at baseline (P = .50), 7 minutes (P = .41), or 15 minutes (P = .82). There was significantly more burning with diclofenac and ketorolac compared to control. There was a small but not statistically significant (P = .28) trend of more burning with ketorolac than diclofenac.
CONCLUSION: Neither diclofenac nor ketorolac were found to decrease corneal sensation compared to controL There was no significant difference in burning upon instillation reported by patients. [J Refract Surg 2002;18:145-148]
U.S. Trends in Refractive Surgery: 2001 International Society of Refractive Surgery Survey
Authors: Duffey Richard J , Leaming David 
Published: April 2021

ABSTRACT
PURPOSE: To determine the trends in refractive surgery in the United States in 2001.
METHODS: The 980 U.S. members of the International Society of Refractive Surgery were mailed the 2001 refractive surgery survey dealing with volumes, types, and preferences of refractive surgery performed. Questions regarding radial keratotomy, astigmatic keratotomy, photorefractive keratectomy, laser in situ keratomileusis (LASIK), laser subepithelial keratomileusis, intracorneal rings (lntacs), laser thermal keratoplasty, conductive keratoplasty, clear lens extraction, phakic intraocular lenses, and scleral expansion procedures for presbyopia were examined in the survey. Procedure preferences for low, moderate, and high myopia and hyperopia were compared with the results from the surveys of the previous 4 years. Preference for unilateral versus bilateral same-day surgery, laser type, and microkeratome choice were also compared with the survey data from previous years. Incidence and frequency of comanagement of refractive surgery patients were compared with 2000 data.
RESULTS and CONCLUSION: LASIK remains the dominant refractive surgery for refractive errors from -12.00 to +3.00 D; the VISX excimer laser and the Hansatome microkeratome are the most frequently used instruments for LASIK [J Refract Surg 2002;18:185-188]
Traumatic Dislocation of an Ophtec Artisan Phakic Intraocular Lens
Authors: Yoon Hawke , Macaluso Damien C , Moshirfar Majid , Lundergan Maureen 
Published: April 2021

ABSTRACT
PURPOSE: Tb report a case of a traumatic dislocation of an Ophtec Artisan phakic anterior chamber intraocular lens.
METHODS: Retrospective case review.
RESULTS: A 38-year-old female underwent successful implantation of an Ophtec Artisan lens in her left eye as part of the phase ?? U.S. clinical trials. Approximately 5 months postoperatively, the patient was struck with a roll of packing tape in her left eye and noted immediate decreased vision. Following the blunt trauma, the patient had an uncorrected visual acuity (UCVA) of 20/60 and a best spectacle-corrected visual acuity (BSCVA) of 20/20. The wound was intact, however, the superior claw was no longer enclaved to the iris and the lens had dislocated nasally with the optic of the lens resting in the angle. The patient was taken back to the operating room, the lens was repositioned, and the superior claw was re-enclaved to the iris. One week after repositioning, UCVA was 20/30 and BSCVA was 20/20.
CONCLUSION: Despite adequate positioning, significant trauma may result in the iris claw tearing free from the iris with dislocation of the Artisan lens. The lens may be repositioned with good visual outcome, however, the long-term effects on endothelial cell density in this patient remain to be seen. [J Refract Surg 2002;18:481-483]