bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Minus Power Anterior Chamber Intraocular Lenses and Myopic Epikeratoplasty in Phakic Eyes
Authors: Baikoff G , Joly P 
Published: April 2021

ABSTRACTiWe performed a retrospective study of two sequential series of operations designed to correct high myopia in phakic eyes. The first series consisted of 24 eyes with refractive error ranging from -11.00 diopters to -21.00 D (mean -16.9 D). They received a commercially prepared, lyophilized, myopic epikeratoplasty lenticule sutured into a circular keratectomy. Seven lenticules had to be removed within the first year because of poor refractive results, corneal ulceration, or melting. The nine eyes followed from 12 to 24 months after surgery demonstrated residual refractive errors from + 4.00 D to -11.25 D.
We also studied an initial series of 41 eyes with preoperative myopia ranging from -9.00 D to -35.00 D (mean -15.00 D) that received a minus power anterior chamber intraocular lens. The lens had an open loop design with an anterior vault, four point angle fixation, and an optic diameter of 4.5 mm. Recovery of visual acuity was faster with the intraocular lens than with epikeratoplasty. Three intraocular lenses were removed; two because they were the wrong size and one because it was the wrong power. Two of the lenses were replaced with acceptable results. Of the 34 eyes followed for 12 months, all had a residual refractive error within ± 2.00 D of emmetropia. During the short-term followup, no elevated intraocular pressure, cataract formotion, or excessive endothelial damage was observed.
We concluded that anterior chamber minus power intraocular lenses gave more rapid and predictable optical correction in high myopic eyes than did myopic epikeratoplasty. Longer follow-up is required before conclusions can be reached about the safety of these intraocular lenses. [Refractive and Corneal Surgery 1990;6:252-260.]
Does Bowman's Layer Determine the Biomechanical Properties of the Cornea?
Authors: Seiler Theo , Matallana Michael , Sendler Sebastian , Bende Thomas 
Published: April 2021

ABSTRACT
Background: Bowman's layer is believed to be the stabilizing element of corneal curvature due to its assumed mechanical stiffness.
Methods: Uniaxial stress-strain analysis was performed in paired corneal strips to compare the contribution from Bowman's layer. Two central strips were taken from each cornea and Bowman's layer was removed from one of them with the excimer laser.

Results: Pairwise comparison yielded no statistical difference in elastic or viscoelastic properties according to presence or absence of Bowman's layer. At a strain of 2%, the stress was measured to be (5.06 ± 2.01) × 10
p 3
N/m
p 2
with Bowman's layer and (4.72 ± 1.3) × 10
p 3
N/m
p 2
without Bowman's layer. Also, the two relaxation times did not differ significantly.

Conclusions: These findings imply that Bowman's layer does not contribute significantly to mechanical stability within the cornea. (Refract Corneal Surg 1992;8:139-142.)
Photorefractive Keratectomy as a Second Attempt to Correct Myopia After Radial Keratotomy
Authors: Seiler Theo , Jean Benedict 
Published: April 2021

ABSTRACT
BACKGROUND: Undercorrection after radial keratotomy is not uncommon. To correct the residual refractive error, several techniques are available including photorefractive keratectomy.
METHODS: We report five eyes of four patients, which remained undercorrected following radial keratotomy and underwent photorefractive keratectomy with an excimer laser (193 nm) to correct the residual myopia, with a follow up of 6 months to 1 year.
RESULTS: The corneal-healing response was similar to that of corneas treated by photorefractive keratectomy alone. No permanent corneal scarring occurred. The average preoperative refraction before photorefractive keratectomy was -2.25 ± 0.55 diopters; it was close to piano (+0.12 ± 0.26 D) after 6 months. One eye regressed 0.50 D between 6 months and 1 year. Best-spectacle corrected visual acuity did not change.
CONCLUSIONS: Excimer laser photorefractive keratectomy seems to be effective as a second procedure in eyes undercorrected following radial keratotomy. (Refract Corneal Surg 1992;8:21 1214.)
Phototherapeutic Keratectomy With Excimer Laser for Reis-Bückler's Corneal Dystrophy
Authors: McDonnell Peter J , Seiler Theo 
Published: April 2021

ABSTRACT
Two patients with decreased visual acuity and recurrent epithelial erosions due to Reís-Bückler's corneal dystrophy underwent phototherapeutic keratectomy with the 193-nanometer excimer laser. Because the epithelial surface was relatively smooth prior to surgery, ablations were performed through an intact epithelium. Postoperatively, visual acuity was improved and symptoms of erosion decreased in both patients. Although no refractive shift was intended with the phototherapeutic procedure, both patients were hyperopic following surgery. Superficial keratectomy with the 193nanometer excimer laser thus provides an alternative to conventional surgical keratectomy. [Refract Corneal Surg 1992;8:306-310.)
Complications of Radial Keratotomy: Eyes With Keratoconus and Late Wound Dehiscence
Authors: Durand Luc , Monnot Jean-Philippe , Burillon Carole , Assi Alexandre 
Published: April 2021

ABSTRACT
BACKGROUND: Radial keratotomy requires a thorough preoperative examination, including photokeratography, to detect early keratoconus.
METHODS: We compared, by light and transmission electron microscopy, the healing process ot corneas from two patients after radial keratotomy.
RESULTS: Clinically, one patient had a keratoconus and gained no visual benefit from the radial keratotomy. The other patient had a spontaneous corneal perforation at one incision and a hypopyon. Histological studies showed a prolonged healing process in both eyes, with a persistent epithelial plug. Bowman's layer was also interrupted and retracted in both eyes. The inflamed cornea had deep neovascularization.
CONCLUSIONS: These observations imply that 2 years after surgery, wound healing and, therefore, refraction is not stable. The results show the inappropriateness of radial keratotomy performed on eyes with keratoconus, with the possible risk of delayed corneal perforation. Refract Corneal Surg 1992;8:311-314.)
The Treatment of Persistent Wound Leak After Radial Keratotomy
Authors: MacRae Scott , Cox William , Bedrossian Robert , Rich L F 
Published: April 2021

ABSTRACT
BACKGROUND: Macroperforation of the cornea during refractive keratotomy can result in persistent wound leak and may need treatment by suturing.
METHODS: We describe two eyes that developed a mac roperf oration during radial keratotomy with persistent leakage of aqueous. The wounds were sutured with 10-0 and 11-0 nylon sutures.
RESULTS: The sutures induced irregular astigmatism as shown by corneal topography. Removal of sutures improved the topography and led to an acceptable outcome.
CONCLUSION: Macroperforations with persistent aqueous leaks should be sutured. Suture removal within a few weeks after surgery can avoid persistent irregular astigmatism and lead to a good refractive result. Refract Corneal Surg 1993;9:62-64.)
Central Islands of Corneal Steepening After Automated Lamellar Keratoplasty for Myopia
Authors: Price Francis W 
Published: April 2021

ABSTRACT
BACKGROUND: Central steep islands are a phenomena of videokeratography that demonstrate local central steepening within a larger diameter area of the cornea treated by refractive surgery that removed stromal tissue to reduce myopia. This report details four cases in which central steep islands occurred following automated lamellar keratoplasty (keratomileusis in situ).
METHODS: A total of 43 automated lamellar keratoplasty procedures were performed on 32 patients between January 1993 and September 1993. Central islands were identified using videokeratography.
RESULTS: Out of 43 cases of automated lamellar keratoplasty, central steep islands developed in six eyes of four patients. These steep areas developed within a few weeks after surgery; increases in the elevation of these islands correlated with recurring myopia. Slit-lamp microscopy revealed no epithelial surface abnormalities or difficulties with the interface of the resection. A central steep island did not prevent excellent uncorrected visual acuity. After subsequent refractive keratotomy for residual myopia, central steep islands either regressed or disappeared.
CONCLUSION: Central islands of corneal steepening may occur after automated lamellar keratoplasty for myopia. The etiology is unknown. [J Refract Surg. 1996;12:36-41.]
Photorefractive Keratectomy for Myopia of -8.00 to -24.00 Diopters
Authors: Goes Frank J 
Published: April 2021

ABSTRACT
BACKGROUND: Sixty-eight highly myopic eyes (mean refraction, -11.17 diopters [D]; range,-8.00 D to -24.00 D) were treated with excimer laser photorefractive keratectomy and followed 1 year.
METHODS: A 193 nm Meditec excimer laser was used with a 5.0-mm ablation zone without peripheral taper. All patients were followed during a period of at least 1 year. All patients had a complete ophthalmological examination including videokeratography and documentation of haze.
RESULTS: After 1 year, uncorrected visual acuity was 20/20 or better in eight (13%) and 20/40 or better in 48% of eyes; 42% of eyes had a refraction within +0.50 D, 74% within ±1.00 D, and 90% within ±2.00 D of the planned correction. The eyes that needed only a single treatment obtained the best results. In 30% of eyes, two treatments were necessary in order to obtain acceptable results. A decrease of spectacle-corrected visual acuity, caused by the laser treatment, was exceptional, probably transient, and increased when a second treatment was necessary. Subjective complaints were present in four of 68 eyes. Eyes with clinically significant regression had more and longer lasting haze.
CONCLUSION: Excimer laser photorefractive keratectomy for myopia of -8.00 D and more give less predictable results than those achieved for less than -8.00 D. Two treatments improve the outcome but cause more loss of spectacle-corrected visual acuity. [J Refract Surg. 1996;12:91-97.]
Quantifying Corneal Toricity From Videokeratography With Fourier Analysis
Authors: Friedman Nina E , Zadnik Karla , Mutti Donald O , Fusaro Robert E 
Published: April 2021

ABSTRACT
BACKGROUND: Fourier analysis can be used to quantify corneal toricity from videokeratography data. This study measures the repeatability of Fourier-derived toricity values in normal adult corneas.
METHODS: The Topographic Modeling System (TMS) was used to model the corneas of 29 subjects on two occasions, and Fourier analysis applied to the data. Repeatability of Fourier-derived toricity values between sessions was examined, and 95% limits of agreement were established.
RESULTS: The 95% limits of agreement between sessions for the Fourier method were -0.02 ± 0.16 diopters (D) and -0.5 ± 5.7° for toricity amount and axis, respectively.
CONCLUSIONS: The Fourier method yields highly repeatable toricity values and thus provides a sensitive means of detecting longitudinal toricity change in normal corneas. [J Refract Surg. 1996;12:108-113.]
Surface Roughness in PMMA is Linearly Related to the Amount of Excimer Laser Ablation
Authors: O'Donnell Colleen B , Kemner Jason , O'Donnell Francis E 
Published: April 2021

ABSTRACT
OBJECTIVE: To determine if surface roughness after excimer laser ablation is a function of the amount of ablation and to identify a standard unit for ablation roughness.
METHODS: We used a VISX 20/20 excimer laser to perform a series of single zone 6-mm diameter ablations (photorefractive keratectomy [PRK]) in polymethylmethacrylate (PMMA). Corrections ranged from -1.00 diopter (D) to -15.00 D. A scanning white light interferometry microscope (Zygo Corp, Middlefield, Conn) was used to quantify the surface roughness at the center of each ablation.
RESULTS: We found a linear increase in surface roughness as the refractive correction increased. Each diopter increment resulted in an approximately 300 nm increased peak-to-valley measurement. This represented an increase of 25 nm roughness per micron of ablation in PMMA.
CONCLUSIONS: Surface irregularities in PMMA increase with ablation depth. We propose a unit of measure of roughness, the "ablaton," expressed as the peak-to-valley distance in nm/÷m of ablation. [J Refract Surg. 1996;12:171-174.]
Management of Detached Lenticule After In Situ Keratomileusis
Authors: Kim Eung K , Choe Chul M , Kang Shin J , Kim Hong B 
Published: April 2021

ABSTRACT
BACKGROUND: Attachment of a keratomileusis lenticule without sutures is a commonly used technique that reduces surgery time and makes the procedure more simple. Detachment of the lenticule after surgery is a difficult complication to manage.
PATIENTS AND METHODS: Three cases of lenticular detachment occurred among 74 eyes of microkeratome in situ keratomileusis without suture. After thorough washing of the lenticule and stromal bed, the lenticules were reattached with air drying.
RESULTS: In the first eye, the lenticule was reattached successfully with air only. In the second and third eyes, epithelial growth along the interface appeared after reattachment. In spite of removing the epithelium from the interface and suturing the lenticule to the stromal bed four times, the epithelial growth recurred along the interface. Peripheral corneal neovascularization forced the surgeon to abandon more trials of resuturing. In the second eye, the lenticule was discarded because the epithelial growth along the interface could not be blocked. In the third eye, the edge of the lenticule was buried into the stroma, mimicking epikeratoplasty. All three eyes retained useful visual acuity.
CONCLUSIONS: A detached lenticule after microkeratome keratomileusis is difficult to replace without epithelial growth in the interface. This complication may be managed successfully. [J Refract Surg. 1996;12:175-179.]
Laser In Situ Keratomileusis (LASIK) for Myopia from -7 to -18 Diopters
Authors: Güell José L , Muller Ana 
Published: April 2021

ABSTRACT
BACKGROUND: Laser in situ keratomileusis (LASIK) combines a lamellar corneal flap with an excimer laser ablation in the stromal bed to correct a wide range of myopia. We reviewed 43 eyes treated with LASIK to correct -7.00 to -18.50 diopters (D).
METHOD: The data from 43 consecutive eyes of 30 patients aged 24 to 46 years were analyzed. Surgery was performed under topical anesthesia using the Chiron Automated Corneal Shaper and Keracor 116 Excimer laser with the multizone mode and our modified nomogram. Manifest and cycloplegic refraction, uncorrected visual acuity, spectacle corrected visual acuity, videokeratography, endothelial cell count, slit-lamp microscopy, fundus examination, and applanation tonometry were recorded preoperatively and at 1 week and 1, 3, and 6 months, postoperatively.
RESULTS: We divided the eyes into two groups. The lower myopia group had a mean preoperative spherical equivalent refraction of -9.30 ± 1.31 D (range: -7.00 D to -12.00 D) and mean postoperative refraction of -0.80 ± 0.79 (range: -0.25 D to -3.50 D). The mean spectacle corrected visual acuity preoperatively was 0.74 ± 0.20 and postoperatively was 0.74 ± 0.18. The higher myopia group had a mean preoperative spherical equivalent refraction of -14.86 ± 1.87 D (range: -12.25 D to -18.50 D) and a mean postoperative refraction of -1.80 ± 1.29 D (range -1.00 D to -5.25 D). The mean spectacle corrected visual acuity preoperatively was 0.50 ± 0.19 and postoperatively was 0.51 ± 0.18. No overcorrections occurred in either group. One eye of the higher group lost one line of spectacle corrected visual acuity. No eye had visually significant corneal haze. The mean change in spherical equivalent refraction between preoperatively and 6 months postoperatively was 8.50 D for the lower myopia group and 13.06 D for the higher myopia group, in the myopic direction. Visual rehabilitation was rapid after surgery.
CONCLUSIONS: In this study, LASIK resulted in insignificant corneal scarring, stable refractive correction over six months, no irregular astigmatism, and excellent visual acuity. Predictability was more accurate up to -12.00 D of intended correction. [J Refract Surg. 1996;12:222-228.]
Comparison of Three Videokeratoscopes in Measurement of Toric Test Surfaces
Authors: Greivenkamp John E , Mellinger Mark D , Snyder Robert W , Schwiegerling James T , Lowman Andrew E , Miller Joseph M 
Published: April 2021

ABSTRACT
PURPOSE: We compared the accuracy of the Computed Anatomy TMS-1 (1.41), the EyeSys Laboratories Corneal Analysis System (2.1), and the Visioptic EH-270 (3.0) videokeratoscopes in measuring toric surfaces. These non-rotationally symmetric aspheric surfaces served as models of corneal astigmatism.
METHODS: Precision diamond-turned toric surfaces modeling 0.00 diopter (D) to 7.00 D of astigmatism were fabricated. A three-dimensional contact profiler was developed to calibrate the aspheric surfaces. Videokeratoscopic data taken at "best focus" were compared to the theoretical shape to quantify device measurement errors.

RESULTS: The Computed Anatomy system measurement accuracy shows no statistically significant correlation between measurement error and surface toricity (r
p 2
<0.13). Measurement error increased linearly with surface astigmatism for the EyeSys Laboratories system (0.12 D rms error per D of astigmatism, r
p 2
>0.96, p<0.001 and the Visioptic system (0.03 D error per D of astimatism, r
p 2
=0.88, p<0.001).

CONCLUSIONS: This study found systematic performance differences among the three machines. Under ideal alignment conditions, the Computed Anatomy TMS-1 is more accurate at detecting astigmatism. The EyeSys Laboratories Corneal Analysis System apparently underestimates the amount of surface astigmatism because of excessive data smoothing. The Visioptic EH-270 errors are primarily in the central zones and may be due to ring localization errors. [J Refract Surg. 1996;12:229-239.]
A Computer Model for Predicting Image Quality After Photorefractive Keratectomy
Authors: Klonos Gregory G , Pallikaris John , Fitzke Frederick W 
Published: April 2021

ABSTRACT
BACKGROUND: Accurately predicting visual performance remains a concern in refractive surgery. The effects of the eye's optics on retinal image quality were investigated using computer ray tracing to model the human eye after photorefractive keratectomy (PRK).
METHODS: Ray-tracing analysis was used with an anatomically realistic model of the human eye including aspheric surfaces and crystalline lens grathent index distributions. The contribution of corneal curvature to refractive error was investigated using data of axial length, corneal power, anterior chamber depth, and lens power from 318 eyes from the literature. The computer interface was specifically designed for use with PRK and provides graphical plots of the remodeled eye, ray paths and retinal image formation.

RESULTS : Modeling the optical contribution of corneal curvature resulted in an improvement in predicted refractive state of the eye as a function of axial length expressed as the R
p 2
value of the regression analysis from 0.88 to 0.96. Subsequently, analyses were conducted for single and multizone treatment areas of differing diameter and with varying pupil size. Retinal image quality following PRK for the human cornea was found to be affected by not only the corneal parameters of anterior curvature and thickness, but also by axial length, pupil size, and anterior chamber depth.

CONCLUSIONS: The inclusion of multiple interdependent optical parameters showed differences from conventional methods in predicting refractive outcome following PRK and revealed factors affecting image quality may account for some imperfections in visual performance based on simpler optical modeling. [J Refract Surg. 1996;12:S280-S284.]
Night Vision Testing in Unoperated Eyes
Authors: Florakis George J , Jewelewicz Daniel A , Fan Nancy I , Trokel Stephen L 
Published: April 2021

ABSTRACT
BACKGROUND: We previously described a simple test which evaluates image degradation in post-excimer laser (PRK) patients under scotopic conditions. After refractive surgery, corneal haze, ablation zone decentration, ablation zone/pupillary diameter disparity, and under-correction each result in a characteristic pattern on the Night Vision Recording Chart.
METHODS: Using the same method, further studies evaluated night vision image degradation in 118 un-operated emmetropic, myopic, hyperopic, and astigmatic eyes and in 26 contact lens wearers.
RESULTS: Scotopic image degradation increases with myopic refractive error, image displacement increases with astigmatism, and contact lens wearers have more image degradation that with spectacle correction.
CONCLUSION: Our Night Vision Recording Chart offers a simple, reproducible method to characterize image degradation under scotopic conditions. [J Refract Surg. 1996;12:S311-S312.]
Histological Evaluation of Phthalocyanine Mediated Photodynamic Occlusion of Corneal Neovascularization Enhanced by Hyperbaric Oxygenation
Authors: Pallikaris I G , Margaritis V N , Naoumidi I I , Naoumidis L P , Tsilimbaris M K , Panagopoulos J A , Tsamparlakis I C 
Published: April 2021

ABSTRACT
PURPOSE: We evaluated the effective irradiation parameters for photodynamic thrombosis of experimental corneal neovascularization enhanced by simultaneous hyperbaric oxygenation.
METHODS: Neovascularization was provoked in both eyes of each of 35 albino rabbit corneas using the intracorneal suture technique. The lasered animals were divided in 3 groups. Group 1 (10 rabbits) was treated under hyperbaric conditions (28 atm for 25 min.); group 2 (5 rabbits) was treated breathing pure oxygen delivered by a face mask; group 3 (10 rabbits) was treated breathing room air. The fourth group (10 rabbits) was used for control. Animals were anaesthetized, and irradiation of new corneal vessels was carried out 30 minutes after the injection of 5 mg/kg chloroaluminum sulfonated phthalocyanine. A 670 nm diode laser with a power 4 mW and a spot diameter 350 nun was used. Exposure times necessary for vascular occlusion were registered. Histological examination was carried out at the end of the follow-up time.

RESULTS: Exposure times were significantly lower in groups 1 and 2 as compared to group 3 (1.75 ± 0.15 min., 3.1 ± 0.4 min., and 4.75 ± 0.15 min. respectively). Total light dose averaged 490 J/cm,
p 2
870 J/cm,
p 2
and 1330 J/cm,
p 2
respectively. Histological examination revealed thrombus formation in the targeted vessels of all three investigated groups.

CONCLUSION: Combination of PDT with hyperbaric oxygenation results in an acceleration of the photodynamic process and provides for a possibility of significant reduction of photodynamic dose. [J Refract Surg. 1996;12:S313-S316.]