bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Videokeratoscope and Autokeratometer Measurements on Ellipsoid Surfaces and Human Corneas
Authors: Pardhan Shahina , Douthwaite William A 
Published: April 2021

ABSTRACT
BACKGROUND: Various studies have compared the accuracy and repeatability of autokeratometers and videokeratoscopes using calibrated convex surfaces. We investigate the agreement between the Topcon KR-3500 autokeratometer and the EyeSys videokeratoscope on human corneas and calibrated convex surfaces.
METHODS: Measurements were obtained from 30 convex ellipsoidal buttons and 20 right eyes of 20 young normal human subjects. Vertex radius and pvalues were compared for the two instruments.
RESULTS: The two instruments showed excellent agreement on convex buttons. The human data showed no such relationship. For vertex radius, a good level of agreement was obtained only for surfaces whose p-values were near unity. Repeatability was also calculated and was shown to be better with the Topcon autokeratometer than with the EyeSys videokeratoscope. Editing the EyeSys data to encompass the same corneal area as that of the Topcon improved its repeatability, although it did not reach the level of the Topcon autokeratometer.
CONCLUSIONS: The Topcon autokeratometer and the EyeSys videokeratoscope showed reasonable agreement for surface topography on convex conicoidal plastic test buttons but not for human corneas. Alterations in the data-capture mechanisms of videokeratoscopes could improve their ability to accurately image paraboloidal surfaces. [J Refract Surg 1998;14:414-419]
Photorefractive Keratectomy for Hyperopia Using an Erodible Disc and Axicon Lens: 2-Year Results
Authors: Carones Francesco , Brancato Rosario , Morico Alessandro , Vigo Luca , Venturi Elisabetta , Gobbi Pier Giorgio 
Published: April 2021

ABSTRACT
BACKGROUND: This paper presents the results over a 2-year follow-up of the first human trial of photorefractive keratectomy (PRK) for correction of hyperopia using an erodible disc excimer laser delivery system (Summit) coupled to an axicon lens.
METHODS: We treated 25 eyes of 21 patients for a mean correction of +3.38 ± 0.97 D (range, +1.00 to +4.00 D). The hyperopic correction was made using an erodible disc inserted on the laser optical pathway; an axicon lens was then used to create a blend transition zone. Eyes were evaluated at 1, 3, 6, and 12 months after surgery. For a smaller series of 11 eyes, we also present 24-month results.
RESULTS: Mean refractive error 1 month after treatment (25 eyes) was -2.35 ± 1.55 D (range, +1.00 to -6.50 D). Eight eyes (32%) had a spectacle-corrected visual acuity loss greater than 1 bine. Twelve months after treatment, mean spherical equivalent refraction was -0.47 ± 0.80 D (range, +1.25 to -2.25 D). Nineteen eyes showed an improvement (range, 3 to 8 lines) in uncorrected distance visual acuity and 23 showed improvement in uncorrected vision at reading distance (1 to 7 lines).
CONCLUSION: This technique proved effective in reducing hyperopia, but predictability must be demonstrated in a larger treatment group. Safety was confirmed by the absence of delayed reepithelialization and the absence of spectacle-corrected visual acuity loss greater than 1 line at 1 year after surgery. [J Refract Surg 1998;14:504-511]
Excimer Laser Lamellar Keratoplasty of Augmented Thickness for Keratoconus
Authors: Buratto Lucio , Belloni Sergio , Valeri Renato 
Published: April 2021

ABSTRACT
PURPOSE: We describe a modified surgical technique for the treatment of patients in the early stage of keratoconus, when it is still possible to correct the astigmatic ametropia with contact lenses.
METHODS: Excimer laser lamellar keratoplasty of augmented thickness (ELLKAT) is a procedure in which a deep piano excimer laser ablation is done on the host cornea and a donor lamellar buttonwith or without an excimer laser refractive ablation on the posterior surface- is sutured into the recipient bed. In 12 of 20 eyes, the homoplastic button, which had parallel faces and was devoid of any dioptric power, was treated refractively on its stromal face with a Chiron Keracor 116 excimer laser to correct the axial and/or induced myopia present due to the weakened cornea.
RESULTS: The 8 eyes that received donor buttons without excimer laser ablation had improved spectacle-corrected visual acuity from a mean preoperative value of 20/100 (no eye saw 20/40 or better before surgery) to a mean postoperative value of 20/30 after 18 months. Mean refractive astigmatism was reduced from 4.84 ± 2.34 D to 1.00 1 0.46 D. Mean keratometric power was reduced from 56.75 ± 8.01 D to 44.21 ± 2.12 D. The associated mean spherical equivalent refraction was reduced from -4.75 to -3.00 D. Mean corneal thickness increased from 422.25 ± 83 µm preoperatively to 562.87 ± 57.81 µm postoperatively. The 12 eyes that received donor lamellar buttons treated with excimer laser also had improved spectacle-corrected visual acuity from a mean preoperative value of 20/100 to a mean postoperative value of 20/30 after 18 months. Astigmatism was reduced from a mean 4.84 ± 2.77 D to 1.66 ± 1.30 D; mean keratometric power was reduced from 56.08 ± 7.00 D to 45.31 ± 2.08 D; and the associated mean spherical equivalent refraction was reduced from -8.75 to -1.75 D. Corneal thickness increased from a mean 414.25 ± 64.75 µm preoperatively to 576.75 ± 28.23 µm postoperatively.
CONCLUSION: Compared to penetrating keratoplasty, excimer laser lamellar keratoplasty of augmented thickness for keratoconus has the advantage of preserving the host endothelium and of reducing the refractive error in keratoconus. [J Refract Surg 1998;14:517-525]
Differences in Keratocyte Apoptosis Following Transepithelial and Laser-scrape Photorefractive Keratectomy in Rabbits
Authors: Kim Woo-Jung , Shah Sujal , Wilson Steven E 
Published: April 2021

ABSTRACT
BACKGROUND: Anterior stromal keratocyte cells undergo programmed cell death (apoptosis) in response to corneal epithelial injury. Keratocyte apoptosis may be an initiator of the corneal wound healing response that includes keratocyte proliferation and activation, as well as changes to the overlying epithelium, occurring following refractive surgical procedures such as photorefractive keratectomy (PRK). This study compares the effect of laser-scrape and transepithelial PRK on keratocyte apoptosis.
METHODS: Photorefractive keratectomy was performed in both eyes of 10 New Zealand white rabbits using the Summit Apex excimer laser. Surgery was performed using transepithelial PRK in one eye and laser-scrape PRK in the other. The central cornea was analyzed at 4 hours after surgery using a quantitative TUNEL assay that detects fragmented DNA characteristic of apoptosis. Hepatocyte growth factor (HGF) production by keratocytes was detected by immunocytochemistry.
RESULTS: Average apoptotic cells per 400X microscopic field determined by 2 independent masked observers were 0.9 ± 0.5 (scanning electron microscopy) and 0.2 ± 0.2 in the transepithelial PRK group compared with 5.1 ± 2.9 and 4.1 ± 3.2 in the laser-scrape group. The difference between the two groups was statistically significant for both observers (P < .05, ANOVA). HGF was detected within keratocytes throughout the corneal stroma. Less HGF was detected in the anterior stroma in the laser-scrape group at 4 hours after surgery, consistent with more anterior keratocyte apoptosis in this group.
CONCLUSIONS: Transepithelial PRK induced less anterior keratocyte apoptosis in rabbbits than laser-scrape PRK. This suggests that transepithelial PRK could be useful in preventing or minimizing refractive regression and subepithelial scarring. [J Refract Surg 1998;14:526-533]
The Call of the Sirens: Ethically Navigating the Sea of Nonvalidated Therapies
Authors: Grimmett Michael R , Sulmasy Daniel P 
Published: April 2021

ABSTRACT
Medical research and innovation are vital to the advancement of medicine and, ultimately, benefit society and individual patients. However, the ethical principles of beneficence, respect for persons, and justice must guide the development and implementation of new practices. Ethical codes governing clinical practice and research already warn practitioners to avoid the use of nonvalidated practices outside of controlled clinical trials. Nonetheless, lack of compliance with these codes places many patients at risk for harm. Ophthalmologists, as well as all physicians, must recommit themselves to these ethical principles and codes and establish more vigorous peer-review methods to protect patients from nonvalidated practices that are implemented without a scientific basis. [J Refract Surgl998;14;559-566]
Experimental Circular Keratotomy for Correction of Corneal Astigmatism
Authors: Wijdh Robert H , van Rij Gabriël 
Published: April 2021

ABSTRACT
PURPOSE: To investigate the effect of circular keratotomy depth and diameter on corneal astigmatism.
METHODS: High astigmatism was induced in 25 human donor eyes by an anterior radial 7-0 silk suture across the corneoscleral Iimbus. With a 6.0, 6.5, 7.0, or 7.5 mm trephine, a 0.3 mm deep circular incision was made in 20 donor eyes. In 5 donor eyes 5 circular incisions were made with a diamond knife set at 0.1, 0.2, 0.3, 0.4, and 0.5 mm depths.
RESULTS: The reduction of astigmatism between the 4 groups in which different trephination diameters were used showed no statistically significant difference (P>.1). The relationship between incision depth and reduction of astigmatism was statistically significant (P<001).
CONCLUSION: Artificially induced corneal astigmatism was reduced by a circular keratotomy in this donor eye model. Deeper incisions showed a greater effect. [J Refract Surg 1998;14:594-5961
Scleral Fixation for a Phakic Anterior Chamber Disc Intraocular Lens
Authors: Maggi Riccardo , Maggi Carlo 
Published: April 2021

ABSTRACT
BACKGROUND: Angle-supported phakic anterior chamber intraocular lenses (IOLs) require a high degree of anterior vaulting, but this can cause an inadequate distance between the IOL and the cornea, especially during rubbing or squeezing of the eye.
METHODS: A vaultless implant was designed by anchoring 3 supple haptics through the anterior chamber into the sclera. Thus, a suspended rather than a wedged implant w$ts achieved.
RESULTS: The lens was implanted in 3 eyes of 2 patients in 1990. Good tolerance of the IOL was maintained over 7 years of follow-up.
CONCLUSION: A suspended anterior chamber phakic IOL maintains an adequate position with lack of bowing and shows promising results. J Refract Surg 1998;14:597-601]
Photorefractive Keratectomy in Eyes with Congenital Nystagmus
Authors: Siganos Dimitrios S , Evangelatou Kyriaki A , Papadaki Theokliti G , Katsanevaki Vikentia J , Dagos Athanassios I , Pallikaris Ioannis G 
Published: April 2021

ABSTRACT
BACKGROUND: We report 2 eyes of 2 patients with nystagmus and myopia who underwent photorefractive keratectomy (PRK) to correct myopia.
METHODS: A 32-year old male patient with a baseline spectacle-corrected visual acuity of 20/40 had PRK with an Aesculap Méditée MEL 60 excimer laser with a suction ring system for correction of a spherical equivalent of -8.25 diopters (D). A 19-year old male patient with baseline spectacle-corrected visual acuity of 20/50 had PRK with an Autonomous Technologies T-PRK flying spot and tracking excimer laser to correct a spherical equivalent of -5.00 D.
RESULTS: Twenty-seven months after PRK, the operated eye of the 32-year old patient had an uncorrected visual acuity of 20/32 and a spectaclecorrected visual acuity of 20/25. Six months postoperatively, the operated eye of the 19-year old patient had uncorrected and spectacle-corrected visual acuity of 20/50.
CONCLUSION: Patients with nystagmus are eligible for PRK to correct their refractive error with these two laser systems. [J Refract Surg 1998;14:649-652]
Laser in situ Keratomileusis Interface Deposits
Authors: Hirst Lawrence W , Vandeleur Kevin W 
Published: April 2021

ABSTRACT
BACKGROUND: A clinical investigation was undertaken to determine the origin of a brown interface deposit that developed in 15 eyes after laser in situ keratomileusis (LASEK).
METHODS: The LASBK procedure was evaluated and agents that were thought to be related to these brown deposits in the interface were eliminated sequentially. Eyes were observed after LASBK for presence or absence of the deposit.
RESULTS: Twenty-five consecutive LASES eyes in which a methylcellulose sponge was eliminated as a protector of the hinge developed no similar interface deposits.
CONCLUSION: The use of a dry methylcellulose sponge to protect the hinge may result in unexpected interface deposits after LASBK. [J Refract Surg 1998;14:653-654]
Laser in situ Keratomileusis to Correct Residual Myopia After Cataract Surgery
Authors: Ayala Maria J , Pérez-Santonja Juan J , Artola Alberto , Claramonte Pascual , Alió Jorge L 
Published: April 2021

ABSTRACT
PURPOSE: To evaluate the effectiveness, predictability, and safety of laser in situ keratomileusis (LASIK) for correcting residual myopia after cataract surgery with intraocular lens implantation.
METHODS: Twenty-two eyes of 22 patients underwent LASIK for the correction of residual myopia after cataract surgery. LASIK was carried out using the Chiron Automated Corneal Shaper and the NIDEK EC-5000 excimer laser. In all eyes, the follow-up was 12 months.
RESULTS: Before LASIK, 1 eye (4.5%) had an uncorrected visual acuity of 0.5 or better; 12 months after LASIK, 10 eyes (45.4%) achieved this level of visual acuity and 0 eyes achieved 1.00 or better. Before LASIK, mean refraction was -2.90 ± 1.80 D; 12 months after LASIK it decreased significantly to 0.40 ± 0.60 D (P < .01). In 18 eyes (81.8%) at 12 months after LASIK, spherical equivalent refraction was within ±1.00 D of emmetropia; 11 eyes (50%) were within 0.50 D. No vision-threatening complications occurred.
CONCLUSION: LASIK with the Automated Corneal Shaper and Nidek EC-5000 excimer laser was an effective, predictable, stable, and safe procedure for correcting residual myopia after cataract surgery. No intraocular lens or cataract incision related complications occurred when LASIK was performed at least 3 months after phacoemulsification. [J Refract Surg 2001;17:12-16]
Smoothness of Ablation on Acrylic by Four Different Excimer Lasers
Authors: Argento Carlos , Valenzuela Gonzalo , Huck Hugo , Cremona Gustavo , Cosentino Maria Jose , Gale Maria Fernandez Ruiz 
Published: April 2021

ABSTRACT
PURPOSE: There are many different excimer laser devices available for photoablative refractive surgery. Smoothness of ablation may vary with different excimer lasers systems.
METHODS: Ablations were performed on polymethylmethacrylate (PMMA) plates of 8 x 4 x 0.5 cm, with four different excimer lasers: VISX-Star, Coherent Schwind Keratom I/II, Chiron Technolas Keracor 117C (Plano Scan), and the Nidek EC-5000, to determine and compare the homogeneity and smoothness of the surface. Ten -3.00 D samples, ten -6.00 D samples, and ten -0.00 D samples were ablated with each laser. The PMMA discs were examined with optical microscopy, documented by photographs, and each sample was measured quantitatively using a Hommel-Werkel rugosimeter. We used the same PMMA material throughout.
RESULTS: Statistically significant differences in smoothness were found between the Chiron Technolas 117C and the VISX-Star, Nidek and VISX-Star, and Coherent Schwind and VISX-Star in the homogeneities achieved by ablating -3.00 D. Ablations of -6.00 D resulted in homogeneities that were statistically significantly different: Chiron Technolas 117C with the other three devices, the Nidek EC-5000 with the VISX-Star, and the Coherent-Schwind with the VISX-Star. In the ablations for -9.00 D, statistically significant differences in homogeneity were found between the Chiron Technolas 117C and Nidek, between the Chiron and VISX-Star, between the Coherent Schwind and VISX-Star, and between the Nidek and VISX-Star. The laser with the scanning spot system was smoother.
CONCLUSION: Scanning spot technology produced smooth ablations even up to -9.00 D. [J Refract Surg 2001;17:43-45]
Comparison of Laser in situ Keratomileusis and Photorefractive Keratectomy for the Correction of Myopia of -6.00 Diopters or Less
Authors: Tole Derek M , McCarty Daniel J , Couper Terry , Taylor Hugh R 
Published: April 2021

ABSTRACT
PURPOSE: To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) compared to photorefractive keratectomy (PRK) for the correction of low or moderate myopia (-0.50 to -6.00 D) at 6 months after surgery.
METHODS: The study population comprised a non-randomized consecutive series of 622 eyes of 392 patients who were treated with the Nidek EC-5000 excimer laser. LASER was performed using the ACS Chiron microkeratome on 314 eyes and surface PRK on 308 eyes. All patients were treated using a standard protocol, then assessed at 1, 3, and 6 months postoperatively.
RESULTS: Forty-four percent of the LASIK group and 67% of the PRK group attended their 6-month examination. Eighty percent of patients (111 eyes) after LASEK and 65% (136 eyes) after PRK had an uncorrected visual acuity of 20/20 or better. Spherical equivalent refraction was within ±0.50 D of intended refraction in 78% (109 eyes) for LASEK and 82% (170 eyes) for PRK. Loss of two more lines of best spectacle-corrected visual acuity at 6 months occurred in 1.4% (2 eyes) of the LASEK group and 1.0% (2 eyes) of the PRK group.
CONCLUSION: At 1 month follow-up, the percentage of eyes that achieved 20/20 uncorrected visual acuity was greater in the LASEK group than in the PRK group. At 6 months, visual and refractive outcomes of LASEK and PRK were similar. Although flap related complications occurred only after LASEK, the overall risk of loss of best spectacle-corrected visual acuity was not significantly greater than for PRK. [J Refract Surg 2001;17:46-54]
Surgical Treatment of Keratoconus at the Turn of the 20th Century
Authors: Sekundo Walter , Stevens Julian D 
Published: April 2021

ABSTRACT
PURPOSE: This paper reviews surgical modalities for treatment of keratoconus at the threshold of the 20th century.
METHODS: All ophthalmic literature from 1895 until 1925 in English and German, available at the library of the Institute of Ophthalmology, London, United Kingdom, was studied with respect to this topic.
RESULTS: Three thermal procedures were described; galvanocauterization with perforation, without perforation, and a non-contact application of heat to the corneal apex. Radial extension of a thermal burn to correct the minus cylinder represented a further modification. Excision of the conical area was suggested either as a lamellar dissection or as a full thickness trephination. Incision of the cone appeared to be less popular. In staged procedures, a combination of galvanocauterization, splitting of the cornea, conjunctival flap, and a subsequent optical iridectomy were applied.
CONCLUSION: The treatment of keratoconus 100 years ago used refractive surgery to improve visual function by modifying corneal shape. [J Refract Surg 2001;17:69-73]
Preliminary in vitro Study of the Histological Effects of Low Fluence 193-nm Excimer Laser Irradiation of Corneal Tissue
Authors: Al-qahtani Jerman M , McLean Ian W , Weiblinger Richard P , Ediger Marwood N 
Published: April 2021

ABSTRACT
PURPOSE: To determine if moderate numbers of low fluence, 193-nm excimer laser pulses modify or damage the corneal stroma.

METHODS: The corneal epithelium of fresh bovine eyes was scraped off and the exposed stroma was irradiated with 200 low fluence laser pulses from an argon fluoride excimer laser. This process was performed on five eyes each at two laser fluences, 10 mJ/cm
p 2
and 30 mJ/cm
p 2
. The ten irradiated and three control (unirradiated) corneas were sectioned and studied by electron microscopy. The maximum and minimum thickness of the anterior layer of randomly oriented collagen fibers was measured using electron microscopy.

RESULTS: The mean maximum thickness of the anterior randomly oriented layer of collagen was 1.23 ± 0.45 µm in the control corneas, 0.67 ± 0.32 µm in the corneas irradiated at 10 mJ/cm
p 2
, and 0.10 ± 0.12 µm in the corneas irradiated at 30 mJ/cm
p 2
. The mean thickness of corneal stroma removed was 0.7 µm at a fluence of 10 mJ/cm
p 2
and 1.1 µm at a fluence of 30 mJ/cm
p 2
. A thin, electron-dense pseudomembrane was present at both fluences.

CONCLUSION: We report removal of bovine corneal stroma at 10 mJ/cm
p 2
-below the previously reported ablation threshold of 20 mJ/cm
p 2
. [J Refract Surg 2001;17:105-109]
Laser in situ Keratomileusis for the Correction of Hyperopia From +1.25 to +5.00 Diopters With the Technolas Keracor 117C Laser
Authors: Rashad Khaled M 
Published: April 2021

ABSTRACT
PURPOSE: To assess the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) in patients with hyperopia and to evaluate the visual and refractive results of the procedure.
METHODS: LASIK was performed on 85 eyes of 53 patients for correction of hyperopia, with a preoperative mean manifest spherical equivalent refraction of +3.31 ± 0.69 D (range, +1.25 to +5.00 D) and mean refractive astigmatism of +0.91 ± 1.06 D (range, 0 to +3.00 D). The Carriazo-Barraquer (Moria) manual microkeratome was used to create the corneal flap, and laser ablation was performed using the Technolas Keracor 117C excimer laser with an ablation zone diameter of 6.0 mm and a transition zone diameter to 9.0 mm. Follow-up was 12 months for all patients.
RESULTS: Refraction was stable by 3 months after surgery. At 1 year after LASIK, the mean manifest spherical equivalent refraction was +0.43 ± 0.57 D (range, -1.25 to +2.00 D) and refractive astigmatism was reduced to a mean of 0.36 ± 0.30 D (range, 0 to 1.00 D). Fifty-two eyes (61.2%) had a manifest spherical equivalent refraction within ±0.50 D of emmetropia, and 76 eyes (89.4%) were within ±1.00 D. Uncorrected visual acuity was 20/20 in 21 eyes (24.7%) and 20/40 or better in 79 eyes (92.9%). Spectacle-corrected visual acuity was reduced by two lines in one eye (1.2%) and improved by two lines in five eyes (5.9%). There were no significant complications.
CONCLUSION: LASIK was an effective, safe, and predictable procedure for the correction of hyperopia up to +5.00 D and hyperopic astigmatism up to +3.00 D with the Technolas Keracor 117C excimer laser. The large size of the corneal flap obtained by the Carriazo-Barraquer (Moria) manual microkeratome facilitated laser ablation entirely in the exposed corneal stromal bed. [J Refract Surg 2001;17:113-122]
Laser in situ Keratomileusis: Three Unexpected Complications
Authors: Rosa Daniele Aron 
Published: April 2021

ABSTRACT
PURPOSE: To report unexpected outcomes in three patients after uneventful laser in situ keratomileusis (LASEK) performed using the Nidek EC-5000 excimer laser and the Hansatome microkeratome (Bausch & Lomb Surgical).
METHODS: LASIK was performed with the Nidek EC-5000 excimer laser and the Hansatome microkeratome (Bausch & Lomb Surgical) in three patients.
RESULTS: In three patients, unexpected outcomes were observed. One patient treated for -3.00 D of myopia presented with a central island. One patient treated for +2.00 D (+1.00 x 90°) of hyperopia in both eyes ended up emmetropic in one eye and overcorrected in the fellow eye. The third patient with -12.00 D (-2.00 x 180°) of myopia was treated as -8.60 -1.00 x 180° and at last examination was +4.00 D. During these sessions, all other patients treated were within ±0.50 D of emmetropia.
CONCLUSION: After LASIK with the Nidek EC-5000 excimer laser and the Hansatome microkeratome (Bausch & Lomb Surgical), unexpected outcomes may still occur, despite controlling all the usual variables. [J Refract Surg 2001;17(suppl): S177-S179]