bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of Pain After Photorefractive Keratectomy
Authors: Verma Seema , Marshall John
Published: April 2021

ABSTRACT

BACKGROUND: The inadequate control of pain after photorefractive keratectomy remains an important issue for both patients and clinicians.

METHOD: A survey of postoperative pain regimens used in excimer centers worldwide was carried out. A pilot study to assess the temporal basis of pain after photorefractive keratectomy was done by using a visual analog pain score in 30 patients. A comprehensive literature search was undertaken to ascertain the suitability of topical ophthalmic anesthetics in controlling pain after photorefractive keratectomy.

RESULTS: Many drugs, both oral and topical, are used worldwide to control pain after photorefractive keratectomy, but no group has shown satisfactory pain control in all patients. The pilot study revealed that the pain was most severe in the first 24 hours after photorefractive keratectomy and declined to low levels thereafter. Topical anesthetics cause corneal complications when used excessively and for prolonged periods.

CONCLUSION: Pain after photorefractive keratectomy is most severe in the first 24 hours. Topical anesthetics would only be needed for this short time and would guarantee pain relief in all patients. We do not anticipate any corneal complications if the anesthetics are used for short times and under close medical supervision. [J Refract Surg. 1996,12:358-364.]
Quantitative Measurement of Corneal Haze After Myopic PRK
Authors: Chang Shou-Sung , Maurice David M , Ramirez-Florez Susana
Published: April 2021

ABSTRACT

OBJECTIVE: To design and evaluate an instrument for the objective measurement of haze in rabbits after myopic PRK.

METHODS: A circular fluorescent lamp bulb projected light onto the cornea through a circular collimating aperture covered with an orange filter. The image was collected on a centrally mounted CCD camera and the profile of the haze circle along its horizontal diameter determined.

RESULTS: Haze circles were observed and quantitated. In the first weeks, they were donut-shaped, frequently with a central bright area, but later they became square-topped. The instrument reproduced measurements with an error of a few percentage points and showed good long-term stability. [J Refract Surg. 1996;12:412-416.]
Transient Central Corneal Steepening After Radial Keratotomy
Authors: Suzard Kurt A , Fundingsland Bradley R , Friedlander Miles
Published: April 2021

ABSTRACT

Three case studies are presented illustrating topographic transient central steep island following radial keratotomy. Three stages are apparent: fîrst, a central corneal steepening; next, an overcorrection with exaggerated central flattening; and, finally, the final refractive correction. The steepening is probably caused by temporary midperipheral swelling of the cornea. [J Refract Surg. 1996;12:521-525.]
Diclofenac and Ketorolac in the Treatment of Pain after Photorefractive Keratectomy
Authors: Weinstock V Moss , Weinstock David J , Weinstock S Joseph
Published: April 2021

ABSTRACT

BACKGROUND: Photorefractive keratectomy (PRK) can produce significant ocular pain. Topical diclofenac, a non-steroidal anti-inflammatory drug (NSAID), is effective in the reduction of this pain. This study compares a second NSAID, ketorolac, to diclofenac.

METHODS: This prospective matched-control study involved 102 eyes of 102 patients. Prior to PRK, patients were randomly assigned to receive ketorolac or diclofenac drops. At the first postoperative visit, a standardized questionnaire was used to assess the patient's average and peak levels of discomfort. In addition, the quantities of acetaminophen and codeine consumed were recorded.

RESULTS: The overall level of discomfort was 1.53 ± 0.64 for diclofenac and 1.88 ± 0.55 for ketorolac (scale: 0 to 4)(P=0.004). The diclofenac group reported a peak discomfort level of 2.0 ± 0.75 and the ketorolac group reported 2.3 ± 0.62 (P > 0.05). The diclofenac group consumed 2000 ±1150 mg of acetaminophen and 92 ± 54 mg of codeine whereas the ketorolac group consumed 2150 ± 940 of acetaminophen and 98 ± 50 mg of codeine (P > 0.05).

CONCLUSIONS: The differences in levels of peak discomfort, acetaminophen ingestion, and codeine ingestion, were not statistically significant. As compared to ketorolac, diclofenac resulted in a statistically significant lower mean overall discomfort. [J Refract Surg 1996;12:792-794].
Phototherapeutic Keratectomy for Granular and Lattice Corneal Dystrophies at 1.5 to 4 Years
Authors: Nassaralla Belquiz A , Garbus Jenny , McDonnell Peter J
Published: April 2021

ABSTRACT

BACKGROUND: The capability of the 193-nm excimer laser to ablate the cornea and to remove opacities and various other corneal diseases in a procedure called phototherapeutic keratectomy (PTK) has been demonstrated. In this study we evaluated the long-term results of PTK for treatment of granular and lattice corneal dystrophies.

METHODS: Four eyes with granular or lattice corneal dystrophy were treated with a mean followup of 47.8 months (range, 36 to 58 months). Focal ablations of the central cornea with an ablation zone of 5.5 to 6.0 mm were performed. Ablation depth was 110 µt? in three eyes and 140 /on in one eye.

RESULTS: Removal of corneal opacities allowed for improvement in corrected visual acuity in all patients. Mean corneal thickness in the area of pathology decreased from 0.583 mm before surgery to 0.449 mm after surgery. Spherical equivalent of the manifest refraction measurements increased by a mean of +5.09 D. There were no major complications, but all patients developed slight haze. There was a hyperopic shift in three eyes.

CONCLUSION: Our long-term results suggest that PTK is a safe and effective alternative to penetrating and lamellar keratoplasty in patients with granular or lattice corneal dystrophies. [J Refract Surg 1996;12:795-800]
Laser in situ Keratomileusis to Correct Hyperopia from +4.25 to +8.00 Diopters
Authors: Göker Sinan , Er Hamdi , Kahvecioglu Cezmi
Published: April 2021

ABSTRACT

OBJECTIVE: To evaluate the efficacy and predictability of laser in situ keratomileusis (LASIK) for hyperopia in a prospective study of 54 eyes of 29 patients.

METHODS: Before LASIK, 44 eyes (81.48%) had a spectacle-corrected visual acuity of 20/20 or better, and 54 eyes (100%) had 20/40 or better. Surgery was performed under topical anesthesia using the Keracor 116 excimer laser and Chiron automated corneal shaper. Mean follow-up was 19 months.

RESULTS: Mean baseline uncorrected hyperopia was +6.50 ± 1.33 D (range, +4.25 to +8.00 D). Mean uncorrected manifest spherical equivalent refraction was +0.44 ± 1.95 D at 18 months after LASIK. Twenty-one eyes (38.8%) were within ±0.50 D of emmetropia, 41 eyes (75.92%) were within ±1.00 D, and 47 eyes (87.03%) were within ±2.00 at 18 months after LASIK. Uncorrected visual acuity was 20/20 or better in eight eyes (14.81%) and 20/40 or better in 36 eyes (66.66%) 18 months after LASIK. Regression and undercorrection of more than 2.00 D occurred in seven eyes (12.9%) between the 3 and 6 month examinations; three of these seven eyes (42.8%) required retreatment to correct residual hyperopia. Three eyes (6.8%) lost two or more lines of spectacle-corrected visual acuity.

CONCLUSION: Excimer laser keratomileusis in situ with the Keracor 116 appears to be an effective and safe procedure to decrease low and moderate hyperopia, but the predictability of the procedure needs improvement. [J Refract Surg 1998;14:26-30]
Late Onset of Haze Associated with Viral Keratoconjunctivitis Following Photorefractive Keratectomy
Authors: Pineda Roberto , Talamo Jonathan H
Published: April 2021

ABSTRACT

BACKGROUND: To report a newly recognized cause of late onset of corneal haze following photorefractive keratectomy (PRK).

METHODS: A 35-year old woman who underwent uneventful PRK and subsequently developed viral keratoconjunctivitis 1 year after treatment.

RESULTS: During resolution of the viral keratoconjunctivitis, the patient developed extensive central corneal subepithelial infiltrates and anterior stromal fibrosis in the PRK ablation zone. More than 1 year after the initial infection, the central subepithelial fibrosis persisted, complicated by myopic regression, central steep island on videokeratography, and loss of five lines of spectacle-corrected visual acuity. By the end of the second year after the infection, visual acuity had improved with disappearance of the central steep island on videokeratography. However, the myopic regression and subepithelial fibrosis remained.

CONCLUSION: Patients who undergo PRK may be at greater risk of visual loss following viral keratoconjunctivitis secondary to persistent subepithelial infiltrates and/or stromal fibrosis within the PRK treatment zone. [J Refract Surg 1998;14:147-1511
A Method for Examining Surface and Interface Irregularities after Photorefractive Keratectomy and Laser in situ Keratomileusis: Predictor of Optical and Functional Outcomes
Authors: Vinciguerra Paolo , Azzolini Marco , Radice Paola , Sborgia Maurizio , De Molfetta Vito
Published: April 2021

ABSTRACT

PURPOSE: To develop a system for the examination of the ablated surface after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASER) and to correlate the surface regularity to the functional outcome.

METHODS: A Nidek Eas-1000 Anterior Eye Segment Analysis System was used to examine the ablated surface or the interface regularity immediately after PRK and LASIK. Eighty eyes were evaluated and divided into three study groups: group 1; regularity (18 eyes), group 2; mild irregularity (32 eyes), group 3; severe irregularity (30 eyes).

RESULTS: At 12 months postoperatively, group 1 (regularity) showed the best percentage of eyes with O haze (100%) and with a refraction ±1.00 D of piano (89%); group 2 (mild irregularity) 84% had 0 haze and 62% were ±1.00 D of piano; group 3 (severe irregularity) 27% had 0 haze and 47% were ±1.00 D of piano.

CONCLUSION: The patients with no postoperative irregularity had a sharply lower incidence of haze and a better refractive outcome with respect to piano, confirming the influence of ablation regularity on the results and the importance of this analysis in clinical practice. [J Refract Surg 1998,14:S204-S206]
Accuracy of Visual Correction in Photorefractive Keratectomy
Authors: Deva Jenny P
Published: April 2021

ABSTRACT

PURPOSE: To investigate the accuracy of preoperative optical assessment and other factors that influenced the final visual outcome after photorefractive keratectomy (PRK).

METHODS: The records of 126 eyes from 54 male and 72 female eyes were studied retrospectively, ranging from 6 months to 3 years post-PRK. Refractive errors ranged from low to high myopia and astigmatism, and proper and careful preoperative selection of patients was made. A single standard ablation zone (AZ) of 6.00mm and transition zone (TZ) of 7.00mm was made in all cases.

RESULTS:The study population showed a high degree of accuracy in visual outcome. In simple myopia, 92.3% of female eyes and 84.1% of male eyes had a visual acuity of more than 6/9 or better. In myopia with astigmatism, 83.05% of female and 65.9% of male eyes had a visual acuity of 6/9 (20/40) or better. However, despite the residual myopia, whether with or induced astigmatism, post PRK visual acuity seemed to be less influenced by it, than as in the pre-PRK status.

CONCLUSION: This study showed an accuracy in visual outcome of >90% for females and >80% for males. The Nidek EC-5000 was satisfactory for its purpose. [J Refract Surg 1998;14:S215-S217]
Posterior Chamber Phakic Intraocular Lens for Hyperopia of +4 to +11 Diopters
Authors: Davidorf Jonathan M , Zaldivar Roberto , Oscherow Susana
Published: April 2021

ABSTRACT

PURPOSE: To examine the efficacy, predictability, stability, and safety of posterior chamber phakic intraocular lens (IOL) implantation in eyes with high hyperopia.

METHODS: We analyzed the results of 24 eyes that received a posterior chamber hydrogel-collagen plate phakic IOL (Staar Collamer Implantable Contact Lens, ICL) for the correction of hyperopia with the goal of emmetropia. Mean follow-up was 8.4 months (range, 1 to 18 mo).

RESULTS: The mean preoperative spherical equivalent refraction was +6.51 ± 2.08 D (range, +3.75 to +10.50 D). Mean postoperative spherical equivalent refraction at last examination was -0.39 ± 1.29 D (range, +1.25 to -3.88 D), with 79% (19 eyes) within ±1.00 D and 58% (14 eyes) within ±0.50 D of emmetropia. Postoperative uncorrected visual acuity at last examination was 20/20 or better in 8% (two eyes) and 20/40 or better in 63% (15 eyes). A gain of two or more lines of spectacle-corrected visual acuity was seen in two eyes (8%) at last examination. One eye (4%) lost two or more lines of spectacle-corrected visual acuity due to progressive neovascular glaucoma initiated by early postoperative pupillary block.

CONCLUSION: Posterior chamber phakic IOL implantation with the Staar Collamer plate lens is an effective method for correcting high hyperopia. Large, patent iridotomies are important in hyperopic eyes to lower the risk of postoperative pupillary block. Improved phakic IOL power calculation formulas will refine predictability of refractive outcome. [J Refract Surg 1998;14:306-311]
Hydroepithelial Keratectomy in Rabbits with a Waterjet-based Instrument
Authors: Parolini Barbara , Turdiu Parid , Abelson Marc , Zarbin Marco , Gordon Eugene
Published: April 2021

ABSTRACT

BACKGROUND: Corneal epithelial removal finds multiple applications in ophthalmic surgery (epithelial herpes infections, recurrent epithelial erosion, corneal ulcers and plaques, and intraoperative epithelial clouding). Photorefractive keratectomy is initiated by removal of the epithelium. Current techniques for epithelial removal are suboptimal. We studied the safety and effectiveness of a new technique, hydroepithelial keratectomy, performed with the HydroBrush keratome on live rabbits.

METHODS: Eighteen rabbits (18 eyes) underwent hydroepithelial keratectomy and 18 rabbits (18 eyes) underwent epithelial removal with a surgical blade (blade group). Twelve rabbits were euthanized immediately after the procedure. Twenty-four rabbits were followed for up to 120 hours after treatment. Ultrastructural analysis was performed with light and electron microscopy.

RESULTS: The hydroepithelial keratectomy group healed a mean 53 hours after treatment; the blade group healed a mean 78 hours after treatment. The HydroBrush keratome exposed the basement membrane and the basal cell membrane of the epithelium. The blade exposed patches of basement membrane, as well as stroma and cell debris.

CONCLUSIONS: Hydroepithelial keratectomy with the HydroBrush keratome is effective and safe. Wound healing after hydroepithelial keratectomy is faster than after blade removal. Unlike the blade, the HydroBrush keratome exposed a smooth surface, devoid of debris, with well-defined edges and round shape without hydration nor dehydration of the tissue. [J Refract Surg 1998;14:346-3561
Refractive versus Corneal Changes After Photorefracive Keratectomy for Astigmatism
Authors: Alpins Noel A , Tabin Geoffrey C , Adams Lorraine M , Aldred Geoffrey F , Kent David G , Taylor Hugh R
Published: April 2021

ABSTRACT

PURPOSE: To define measures of assessing success and subsequent ways to improve excimer laser treatment of astigmatism.

METHODS: We studied 97 eyes of 79 patients, followed for 12 months, that underwent photorefractive keratectomy (PRK) for myopia and astigmatism with a VISX 20/20 excimer laser. Preoperative spherical equivalent refraction at the corneal plane was between -1.00 and -15.00 D. Mean preoperative refractive astigmatism at the spectacle plan was -2.17 ± 1.05 D (range, -1.25 to -6.00 D), which is -1.81 ± 0.86 D (range -1.04 to -4.97 D) when calculated at the corneal plane. All patients were examined before and after surgery; examination included refraction, keratometry, and topography measurement.

RESULTS: The success in treatment of astigmatism appeared measurably less than the treatment of sphere when analogous indices were used for assessment. Success in astigmatism surgery improved, as measured by all parameters, after an additional 20% was applied to astigmatism treatment magnitude indicated by the VISX computer algorithm. The sequential modes of treatment undercorrected astigmatism magnitude to a greater extent than elliptical, but equivalent success rates were present in view of the greater astigmatic changes attempted using the sequential mode. The elliptical mode tended to produce a greater undercorrection of associated sphere (p=0.313). Results measured by refraction showed a larger change than those measured by topography and keratometry.

CONCLUSION: During PRK with the VISX 20/20 laser, adjustment for undercorrection of astigmatism treatment achieves a fuller correction of astigmatism. When measuring astigmatic changes, results are different when comparing refractive astigmatism changes with corneal astigmatism changes measured by keratometry and topography. [J Refract Surg 1998;14:386-396]
Evaluation of Pentoxifylline in the Prevention of Haze after Photorefractive Keratectomy in the Rabbit
Authors: Francesconi Claudia M , Abad Juan Carlos , Lim Jonathan E , Talamo Jonathan H
Published: April 2021

ABSTRACT

BACKGROUND: Pentoxifylline (PTX) is a methylxanthine derivative that, besides its hemorrheologic properties, possesses multiple physiologic effects at the cellular level. It has been used in keloid prevention due to its ability to inhibit the secretion of collagen and glycosaminoglycans from activated fibroblasts.

METHODS: Ten New Zealand White (NZW) rabbits underwent a -7.00 diopters, 6.0 mm diameter photorefractive keratectomy after laser ablation of the epithelium with a VISX 20/20 excimer laser. The bare stroma was stained with fresh 0.5% dichlorotriazinyl aminofluorescein (DTAF). The procedure was performed on both eyes, 4 days apart. One eye received 1% Pentoxifylline qid and the other balanced salt solution qid as a control for 4 weeks, starting the same day of surgery. Two masked observers graded the amount of haze at 2, 4, 6, and 8 weeks after surgery using slit-lamp biomicroscopy. Three rabbits were sacrificed at 2 and 4 weeks followed by two rabbits at 6 and 8 weeks. The area between the DTAF-stained collagen to the base of the epithelium was measured using a digital image analyzer.

RESULTS: There was no statistically significant difference in the amount of haze either by slit-lamp microscopy or by histological analysis between the pentoxifylline-treated eyes and the controls at any time interval (Student's f-test: 0.16 to 0.92)

CONCLUSION: Pentoxifylline did not seem to affect haze formation in a PRK rabbit model. As no signs of toxicity were observed, further studies might examine higher concentrations or dose frequencies. [J Refract Surg 1998;14:567-570]
Photorefractive Keratectomy for -1.25 to -25.00 Diopters of Myopia
Authors: Pietilä Juhani , Mäkinen Petri , Pajari Seppo , Uusitalo Hannu
Published: April 2021

ABSTRACT

BACKGROUND: We evaluated prospectively the efficacy, predictability, stability, and safety of photorefractive keratectomy (PRK) for myopia.

METHODS: Three hundred sixty-nine eyes of 257 patients were treated with an Aesculap-Meditec MEL 60 excimer laser. Treated eyes were divided into 3 groups: low myopes (-1.25 to -6.00 D), 226 eyes; medium myopes (-6.10 to -10.00 D), 104 eyes; high myopes (-10.10 to -25.00 D), 39 eyes. Follow-up at 12 months was available for 348 eyes (94%).

RESULTS: One year after surgery the number of eyes within ±1.00 D of emmetropia was 182 (86.7%) for low myopes, 43 (40.5%) for medium myopes, and 12 (30.8%) for high myopes. Values for ±0.50 D were low: 142 (67.6%), medium: 29 (29.3%), and high: 9 (23.1%). Three eyes with low myopia (1.4%) and 5 eyes with medium myopia (5.1%) lost 2 or more lines of spectacle-corrected visual acuity. None of the high myopes lost 2 or more lines. Uncorrected visual acuity of 20/20 or better was achieved in 82 eyes (39%) with low myopia; 20/40 or better was achieved in 183 eyes (87.1%). Five eyes (5.1%) of medium myopes achieved 20/20 or better; 52 eyes (52.5%) with medium myopia achieved 20/40 or better. Zero eyes with high myopia acheived 20/20 or better; 11 eyes (28.8%) achieved 20/40 or better.

CONCLUSION: Photorefractive keratectomy proved to be an effective method to correct myopia up to -6.00 D. For myopia greater than -6.00 D, good results were achieved in most eyes when myopia was less than -10.00 D, but efficacy and predictability decrease. To avoid systematic undercorrection, slight overcorrection must be attempted with the Aesculap-Meditec MEL 60 excimer laser for the treatment of myopia. [J Refract Surg 1998;14:615-622]
Evaluation of Increased Aqueous Outflow After Radial Keratotomy in Enucleated Bovine Eyes
Authors: Perez Edward P , Weinreb Seth , Blanco Ernesto , Miller David
Published: April 2021

ABSTRACT

PURPOSE: We studied the efficacy of using radial keratotomy incisions as a surgical method of increasing outflow facility in enucleated bovine eyes.

METHODS: Each freshly enucleated bovine eye (n=23) was cannulated to a system measuring the rate of flow into the eyes. Preoperatively, corneal thickness measurements were determined for all treated eyes. Radial keratotomy was performed in 13 eyes and a control set of eyes (n=10) had no surgical manipulation. The intraocular pressure was set at 16.9mm Hg. A clear zone of 10 mm was used for each eye with the incision depth set at 100% of the pachymetric reading. One set of experimental eyes had incisions that remained in the clear cornea, and the other set had incisions that reached 2 mm beyond the limfaus into sclera. Preoperative outflow measurements were performed on each eye. Postoperative measurements were made after 10 incisions and 20 incisions. All eyes were checked for perforation after surgery and discarded if a perforation was found.

RESULTS: No eye included in the analysis was perforated. The preoperative (baseline) total flow rate was 27.90 ± 3.72 µ 1/min at 16.9 mmHg. The flow rate increased by 23.5% (over baseline) with 20 radial keratotomy incisions. A paired i-test was used to statistically compare the outflow measurements before radial keratotomy and after the first and second set of radial incisions. The increases in flow were found to be statistically significant (P<005) for both 10 and 20 radial incisions.

CONCLUSION: Assuming the flow measurements (flow rate) in these experiments parallel outflow facility, radial keratotomy increases the outflow facility in enucleated bovine eyes. [J Refract Surg 1998;14:641-645]
Corneal Sensitivity and Some Properties of the Tear Film After Laser in situ Keratomileusis
Authors: Patel Sudi , Pérez-Santonja Juan J , Alió Jorge L , Murphy Paul J
Published: April 2021

ABSTRACT

PURPOSE: To investigate central corneal sensitivity, lipid layer structure of the precorneal tear film, and tear volume after laser in situ keratomileusis (LASIK).

METHODS: Central corneal sensitivity was measured using the Non-Contact Corneal Aesthesiometer. The aesthesiometer was mounted on a slit lamp and an airpulse of controlled pressure was directed onto the cornea. When central corneal sensitivity was reduced, a higher air pulse pressure was required to stimulate the cornea. The final central corneal sensitivity threshold measured was recorded in millibars. Tear lipid layer structure was assessed by optical interferometry and classified according to appearance using the Keeler Tearscope. Tear volume was measured using the phenol red cotton thread test. Subjects were recruited from a group of patients after LASEK who had experienced no complications (n=22). The average postoperative time was 14 weeks and measurements were taken on one eye. In bilateral cases, measurements were recorded from the right eye only. Average attempted correction was -6.30 D (range, -2 to -11 D). Age-matched controls were later recruited for central corneal sensitivity threshold (n=24). A second group of age-matched controls were recruited for tear volume and lipid layer structure (n=24).

RESULTS: The median (range) was 1.1 mbars (0.2 to 4.3 mbars) after LASEK and 0.58 mbars (0.20 to 1.3 mbars) in the controls; the difference was statistically significant (P = .043). The lipid layer of the tear film tended to be thinner in eyes after LASEK compared with controls (P = .032). The mean (± SD) tear volume was 16.9 ± 8.3 mm after LASEK and 19.8 ± 7.1 mm in controls. This difference was not statistically significant (P = .492).

CONCLUSION: At 14 weeks postoperatively, central corneal sensitivity was below normal levels and the tear lipid layer was thinner. The poorer quality lipid layer may predispose to symptoms of dry eye after LASEK. [J Refract Surg 2001;17:17-24]
Treatment of Progressive or Recurrent Epithelial Ingrowth With Ethanol Following Laser in situ Keratomileusis
Authors: Haw Weldon W , Manche Edward E
Published: April 2021

ABSTRACT

PURPOSE: To evaluate the use of ethanol in the treatment of progressive or recurrent epithelial ingrowth following laser in situ keratomileusis (LASIK).

METHODS: Four eyes of four patients with aggressive epithelial ingrowth following LASIK underwent epithelial ingrowth removal with 50% ethanol. Aggressive epithelial ingrowth was defined as, 1) progressive enlargement on serial examination with an area of ingrowth involving at least 30% of the flap surface area, 2) epithelial ingrowth associated with stromal melting as evidence on clinical or topographic examination, or 3) recurrent epithelial ingrowth in the same area following previous removal.

RESULTS: Epithelial ingrowth was removed successfully in all eyes. No eye lost best spectaclecorrected visual acuity. One eye with multiple risk factors for failure experienced nonprogressive recurrence. No eyes required reoperation for recurrent epithelial ingrowth. No eyes experienced progression of stromal melt. Regularization of corneal topography was observed in an eye with preoperative stromal melting. The only complication was a tendency for the development of diffuse lamellar keratitis. Two eyes (50%) experienced diffuse lamellar keratitis following epithelial ingrowth removal with ethanol, which resolved completely with topical corticosteroids.

CONCLUSION: Ethanol may be a useful adjunct in the treatment of aggressive or recurrent epithelial ingrowth following LASIK. Cautious use with the lowest concentration of ethanol may prove useful in these difficult epithelial ingrowth cases. Randomized and prospective studies are recommended to evaluate our experience. [J Refract Surg 2001;17:63-68]
Non-invasive Measurement of Corneal Hydration
Authors: March Wayne F , Bauer Noel J C
Published: April 2021

ABSTRACT

PURPOSE: To investigate the feasibility of a confocal Raman spectroscopic technique for the noncontact assessment of corneal hydration in vivo in two legally blind subjects.

METHODS: A laser beam (632.8 nm; 15 mJ) was maintained on the cornea using a microscope objective lens (25x magnification, NA=0.5, /=10 mm) both for focusing the incident light as well as collecting the Raman backscattered light, in a 180° backseat· ter configuration. An optical fiber, acting as the confocal pinhole for elimination of light from outof-focus places, was coupled to a spectrometer that dispersed the collected light onto a sensitive arraydetector for rapid spectral data acquisition over a range from 2890 to 3590 cm1. Raman spectra were recorded from the anterior 100 to 150 µta of the cornea over a period of time before and after topical application of a mild dehydrating solution. The ratio between the amplitudes of the signals at 3400 cm^sup -1^ (OH- vibrational mode of water) and 2940 cm^sup -1^ (CH-vibrational mode of proteins) was used as a measure of corneal hydration.

RESULTS: High signal-to-noise ratio (SNR 25) Raman spectra were obtained from the human corneas using 15 m J of laser light energy. Qualitative changes in the hydration of the anterior-most part of the corneas could be observed as a result of the dehydrating agent.

CONCLUSION: Confocal Raman spectroscopy could potentially be applied clinically as a noncontact tool for the assessment of corneal hydration in vivo. [J Refract Surg 2001;17(suppl):S205-S210]
Reduction of Hyperopia Associated With Manual Excision of Salzmann's Nodular Degeneration
Authors: Oster John G , Steinert Roger F , Hogan R Nick
Published: April 2021

ABSTRACT

PURPOSE: Removing central corneal pathology often leads to a hyperopic shift secondary to corneal flattening. A myopic shift, or reduction in hyperopia, would be expected after removal of peripheral corneal pathology with central corneal steepening. This case illustrates the refractive changes induced by Salzmann's nodular degeneration and the myopic shift associated with their excision.

METHODS: A 53-year-old female presented with a slowly progressive increase in hyperopia. Vision in the right eye was 20/40 with a refraction of +10.00 -4.00 x 90°. Vision in the left eye was 20/30 with a refraction of +5.75 -2.00 x 105°. Both corneas exhibited nodular subepithelial opacities in the midperiphery. A superficial keratectomy was performed on each eye, 1 year apart.

RESULTS: Twelve days postoperatively, uncorrected visual acuity in the right eye was 20/25, and 20/20 with a refraction of -0.75 -0.50 x 31°, 6 months later. Six days postoperatively, uncorrected visual acuity in the left eye was 20/40, and 20/30 with a refraction of -1.25 D, 1 month later.

CONCLUSION: Superficial keratectomy provides a means of restoring the original corneal contour, especially when the pathology is easily dissected firom Bowman's layer. The surgeon should investigate the refractive status prior to the development of the nodules and be aware of the possible refractive change upon removal of the pathology. [J Refract Surg 2001;1 7:466-469]
Laser in situ Keratomileusis in Children 8 to 15 Years Old
Authors: Nassaralla Belquiz R A , Nassaralla João J
Published: April 2021

ABSTRACT

PURPOSE: To determine the safety, efficacy, predictability, and stability of laser in situ keratomileusis (LASIK) to correct high myopia or high myopic astigmatism in patients with high anisometropia in whom conventional treatments have failed.

METHODS: Nine eyes of nine patients, three boys and six girls with high anisometropia (>3.50 D), were included in this study. Patient age was 8 to 15 years. Minimum follow-up was 12 months. All patients were treated with the Chiron Technolas 217 excimer laser.

RESULTS: Three months after LASIK, uncorrected visual acuity improved by at least five Snellen lines in all eyes. Three eyes (33.3%) were 20/40 or better without correction. Due to dense amblyopia, no eye had uncorrected visual acuity of 20/20 or better. The mean spherical equivalent refraction decreased from -7.66 to -0.22 D, and mean preoperative astigmatism decreased from -3.11 to -0.69 D. Eight eyes (88.8%) were within ±1.00 D of emmetropia. Two eyes (22.2%) were within ±0.50 D of the desired outcome. All patients were able to function binocularly.

CONCLUSION: In this study of selected older children, LASIK was a safe and effective option for the correction of high anisometropia and for improved binocularity, when conventional therapies had failed. Further study is necessary to determine the long-term refractive stability in these young patients. [J Refract Surg 2001;17:519-524]
Removal of Corneal Foreign Bodies Following Laser in situ Keratomileusis
Authors: Porges Yair , Landau David , Douieb Joseph , Levinger Samuel
Published: April 2021

ABSTRACT

PURPOSE: To report the outcome of uncomplicated removal of corneal foreign bodies in patients who previously underwent laser in situ keratomileusis (LASIK).

METHODS: Nine eyes of eight patients presented with corneal foreign bodies after LASIK.

RESULTS: In three patients, diagnosis of corneal foreign bodies was delayed due to reduced pain and symptoms. Removal of foreign bodies was performed with no flap-related complications. Corneal wound healing was normal. Final visual acuity was not decreased.

CONCLUSION: Corneal foreign bodies can be removed safely and effectively from corneas after LASIK. [J Refract Surg 2001;17:559-560]
Laser in situ Keratomileusis for Hyperopia and Hyperopic Astigmatism With the Nidek EC-5000 Excimer Laser
Authors: Pineda-Fernández Angel , Rueda Lizbeth , Huang David , Nur Jorge , Jaramillo Jorge
Published: April 2021

ABSTRACT

PURPOSE: We evaluated the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LAStK) for hyperopia and hyperopic astigmatism.

METHODS: A retrospective study was performed for 92 eyes of 62 consecutive patients to evaluate uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA) and manifest refraction before and 3 and 6 months after IASIK (Moria LSKONE microkeratome, Nidek EC-5000 excimer laser). Eyes were divided into groups: Group 1 (low hyperopia) for spherical correction of +1.00 to +3.00 D (22 eyes), Group 2 (low hyperopic astigmatism) for toric correction with spherical equivalent refraction of +1.00 to +3.00 D (18 eyes), Group 3 (moderate hyperopia) for spherical correction of +3.25 to +6.00 D (10 eyes), and Group 4 (moderate hyperopic astigmatism) for toric correction with spherical equivalent refraction between +3.25 and +6.00 D (18 eyes).

RESULTS: At 3 and 6 months after LASLK, 68 eyes (73.9%) were available for follow-up examination. Percentage of eyes with a spherical equivalent refraction within ?0.50 D of emmetropia for Group 1 was 54.5% (12 eyes); Group 2, 50% (9 eyes); Group 3, 40% (4 eyes), and Group 4, 38.8% (7 eyes). UCVA 2*20/20 in Group 1 was 14% and in Groups 2, 3, and 4, 0%. One eye (5.5%) lost two lines of BSCVA.

CONCLUSION: LASLK with the Moria LSK-ONE microkeratome and the Nidek EC-5000 excimer laser reduced low and moderate hyperopia and was within ?0.50 D of target outcome in approximately 50% of eyes. Undercorrection was evident in all groups. The procedure was safe. [?/ Refract Surg 2001;17:670-675]
Conductive Keratoplasty to Correct Hyperopic Astigmatism
Authors: Pallikaris Ioannis G , Naoumidi Tatiana L , Astyrakakis Nikos I
Published: April 2021

ABSTRACT

PURPOSE: To evaluate the efficacy of conductive keratoplasty in the treatment of pre-existing and surgically induced hyperopic astigmatism.

METHODS: In this prospective, noncomparative case series, four eyes of four subjects, two female and two male (age 25 to 47 yr) were treated for hyperopia (up to +5.50 D) and hyperopic astigmatism (up to +5.75 D) with the Refractee ViewPoint conductive keratoplasty system. The follow-up period was 6 months. Uncorrected and spectaclecorrected visual acuity, manifest and cycloplegic refraction, and videokeratographs were obtained before and after surgery. We treated two patients who had already had LASDK, one of them with a decentered ablation and the other with flap striae, one patient after PRK, and one patient with keratoconus.

RESULTS: No complications were observed. No eye lost lines of spectacle-corrected visual acuity. All eyes showed improvement of uncorrected visual acuity of 3 or more lines. Videokeratographs demonstrated improved centration and reduction in keratometric power readings. Each eye was analyzed separately, including a comparative analysis of the proposed nomograms and quality of vision after surgery.

CONCLUSIONS: Conductive keratoplasty may be a minimally invasive solution for patients with irregular hyperopic astigmatism, offering improved quality of vision in instances of flap striae by tightening the central cornea. [J Refract Surg 2003;19:425-432]
Optic Nerve Head Blood Flow Using Scanning Laser Doppler Flowmetry After Laser in situ Keratomileusis
Authors: Ozdamar Akif , Ocakoglu Ozcan
Published: April 2021

ABSTRACT

PURPOSE: To investigate ocular blood flow changes following laser in situ keratomileusis (LASIK) in myopic eyes.

METHODS: Seventeen eyes of ten myopic patients were included in the study. Mean age of the seven men and three women was 29.1±2.5 years. Mean spherical equivalent retraction was -7.70±2.52 D. LASEK was performed with the Hansatome microkeratome and Summit SVS Apex excimer laser. Optic nerve head blood flow was measured by using the Heidelberg Retinal Flowmeter preoperatively and postoperatively at 1 day, 1 week, and 1 month. Preoperative ocular blood flow data (blood flow, volume, velocity) were compared with postoperative data using variance analysis. Correlation analysis was performed for age of patients, suction time, and ocular blood flow data.

RESULTS: Mean suction time was 19±7 seconds. There was no significant correlation between suction time, age, and ocular blood flow. We found an increase in blood flow at the lamina cribrosa taken 1 day postoperatively (P=.04). Blood flow returned to preoperative values at the 1-week and 1-month measurements in the lamina cribrosa region. There was no significant change in ocular blood flow data in the neuroretinal rim except an increase in velocity at the lower nasal quadrant on postoperative day 1 (P=.03).

CONCLUSIONS: LASIK caused a temporary increase in blood flow at the lamina cribrosa region of the optical nerve head in healthy myopic eyes. The increase in blood flow may suggest a compensatory change for maintaining blood flow in the ocular nerve head following LASIK-induced ischemia. [J Refract Surg 2003;19:433-4371
Central Corneal Haze Increased by Radial Keratotomy Following Photorefractive Keratectomy
Authors: Shoji Nobuyuki , Hayashi Eri , Shimizu Kimiya , Uga Shigekazu , Sugita Juntaro
Published: April 2021

ABSTRACT

PURPOSE: To report a case of central corneal haze induced by minimally invasive radial keratotomy (mini-RK) after photorefractive keratectomy (PRK) and subsequent deep lamellar keratoplasty.

METHODS: We report a case (one eye of one patient) of central corneal haze that worsened after mini-RK was performed 2 years following PRK. Four years later, a second PRK was done, myopic regression was subsequently observed, and corneal haze persisted. Deep lamellar keratoplasty was performed and a corneal graft was taken, which was examined by light and electron microscopy.

RESULTS: In the ablated area, irregularity of the basal membrane and hypertrophy of the corneal epithelium were observed. In the stromal layer, collagen fibers showed disorder in their disposition. Aggregated activated keratocytes were observed. An epithelial plug filling the gap of the RK incision persisted for 6 years after the mini-RK. The RK incision was easily divided when deep lamellar keratoplasty was performed and the patient obtained a stable visual outcome.

CONCLUSIONS: It is possible that mini-RK enhancement after PRK induces central corneal haze and reduces corneal integrity. Deep lamellar keratoplasty for refractory corneal haze after refractive surgery was useful in this eye. [J Refract Surg 2003;19:560-565]
Use of Market Segmentation to Identify Untapped Consumer Needs in Vision Correction Surgery for Future Growth
Authors: Loarie Thomas M , Applegate David , Kuenne Christopher B , Choi Lawrence J , Horowitz Diane P
Published: April 2021

ABSTRACT

PtTRPOS)E): Market segmentation analysis identifies discrete segments of the population whose beliefs are consistent with exhibited behaviors such as purchase choice. This study applies market segmentation analysis to low myopes (-1 to -3 D with less than 1 D cylinder) in their consideration and choice of a refractive surgery procedure to discover opportunities within the market.

METHOD: A quantitative survey based on focus group research was sent to a demographically balanced sample of myopes using contact lenses and/or glasses. A variable reduction process followed by a clustering analysis was used to discover discrete belief-based segments. The resulting segments were validated both analytically and through in-market testing.

RESULTS: Discontented individuals who wear contact lenses are the primary target for vision correction surgery. However, 81% of the target group is apprehensive about laser in situ keratomileusis (XiASK). They are nervous about the procedure and strongly desire reversibility and exchangeability.

CONCLUSION: There exists a large untapped opportunity for vision correction surgery within the low myope population. Market segmentation analysis helped determine how to best meet this opportunity through repositioning existing procedures or developing new vision correction technology, and could also be applied to identify opportunities in other vision correction populations. [J Refract Surg 2003;19:566-5761
Adaptive Optics for Vision: The Eye's Adaptation to Point Spread Function
Authors: Artal Pablo , Chen Li , Fernández Enrique J , Singer Ben , Manzanera Silvestre , Williams David R
Published: April 2021

ABSTRACT

PURPOSE: Despite the fact that ocular aberrations blur retinal images, our subjective impression of the visual world is sharp, which suggests that the visual system compensates for subjective influence. If the brain adjusts for specific aberrations of the eye, vision should be clearest when looking through a subject's typical wave aberration rather than through an unfamiliar one. We used adaptive optics techniques to control the eye's aberrations in order to evaluate this hypothesis.

METHODS: We used adaptive optics to produce point spread functions (PSFs) that were rotated versions of the eye's typical PSF by angles in 45° intervals. Five normal subjects were asked to view a stimulus with their own PSF or with a rotated version, and to adjust the magnitude of the aberrations in the rotated case to match the subjective blur of the stimulus to that seen when the wave aberration was in typical orientation.

RESULTS: The magnitude of the rotated wave aberration required to match the blur with the typical wave aberration was 20% to 40% less, indicating that subjective blur for the stimulus increased significantly when the PSF was rotated.

CONCLUSION: These results support the hypothesis that the neural visual system is adapted to an eye's aberrations and has important implications for correcting higher order aberrations with customized refractive surgery or contact lenses. The full visual benefit of optimizing optical correction requires that the nervous system compensate for the new correction. [J Refract Surg 2003;19: S585-S587]
Ablation Centration in Laser in situ Keratomileusis for Hyperopia: Comparison of VISX S3 ActiveTrak and VISX S2
Authors: Giaconi JoAnn A , Manche Edward E
Published: April 2021

ABSTRACT

PURPOSE: To compare ablation centration and outcome measurements in laser in situ keratomileusis (LASIK) for hyperopia using the pupiltracking VISX S3 ActiveTrak or the nontracking VTSX S2 excimer laser.

METHODS: In a retrospective study, 49 consecutively treated hyperopic eyes (32 patients) that had LASIK by the VISX StarS3 ActiveTrak were compared to 49 control-matched eyes treated with the VISX StarS2 without pupil-tracking. Primary outcome variables including ablation centration, uncorrected visual acuity, best spectacle-corrected visual acuity, manifest refraction, complications, and induced cylinder analyzed by vector analysis were evaluated 3 months postoperatively.

RESULTS: Hyperopic sphere ranged between piano and +5.50 D and cylinder between 0 and +2.75 D. Ninety-five of 98 eyes (96.9%) were available for analysis at 3 months. Of these 95, 52 eyes could be used for analysis of ablation centration. Mean decentration of the ablation zone from the entrance pupil was 0.30 ± 0.20 mm in tracked eyes (n=31) and 0.41 ± 0.39 mm in nontracked eyes (n=21), P=.17. Two eyes (6.5%) in the tracked group were significantly decentered between 0.5 and 1 mm from the pupil center. In the nontracked group, decentration was between 0.5 and 1 mm in one eye (4.8%) and greater than 1 mm in two eyes (9.5%).

CONCLUSIONS: Comparable ablation centration in LASIK for hyperopia was achieved between actively-tracked and nontracked eyes. Decentrations (greater than 1 mm) were not seen with a tracking system in this study. Visual and refractive results were similar between the VISX StarS3 ActiveTrak and VISX StarS2 laser systems. [J Refract Surg 2003;19:629-635]
Factors Influencing Flap and INTACS Decentration After Femtosecond Laser Application in Normal and Keratoconic Eyes
Authors: Ertan Aylin , Karacal Humeyra
Published: April 2021

Purpose

To compare accuracy of LASIK flap and INTACS centration following femtosecond laser application in normal and keratoconic eyes.

Methods

This is a retrospective case series comprising 133 eyes of 128 patients referred for refractive surgery. All eyes were divided into two groups according to preoperative diagnosis: group 1 (LASIK group) comprised 74 normal eyes of 72 patients undergoing LASIK with a femtosecond laser (IntraLase), and group 2 (INTACS group) consisted of 59 eyes of 39 patients with keratoconus for whom INTACS were implanted using a femtosecond laser (IntraLase). Decentration of the LASIK flap and INTACS was analyzed using Pentacam.

Results

Temporal decentration was 612.56±384.24 µm (range: 30 to 2120 µm) in the LASIK group and 788.33±500.34 µm (range: 30 to 2450 µm) in the INTACS group. A statistically significant difference was noted between the groups in terms of decentration (
P
<.05). Regression analysis showed that the amount of decentration of the LASIK flap and INTACS correlated with the central corneal thickness in the LASIK group and preoperative sphere and cylinder in the INTACS group, respectively.

Conclusions

Decentration with the IntraLase occurred in most cases, especially in keratoconic eyes. The applanation performed for centralization during IntraLase application may flatten and shift the pupil center, and thus cause decentralization of the LASIK flap and INTACS. Central corneal thickness in the LASIK group and preoperative sphere and cylinder in the INTACS group proved to be statistically significant parameters associated with decentration. [
J Refract Surg.
2008;24:797–801.]
Retinal Burns From Experimental Laser Iridotomy
Authors: Bongard Bonnie , Pederson Jonathan E
Published: April 2021

ABSTRACT

Simulated argon laser iridotomy was performed in 12 cynomolgus monkey eyes to evaluate the effectiveness of the Abraham iridectomy lens in preventing inadvertent retinal burns. At 600 milliwatts, only two of the three eyes developed small retinal burns using the Abraham lens, whereas three eyes developed larger retinal burns without the Abraham lens. At 1000 milliwatts, retinal burns occurred with or without the Abraham lens, but the size and intensity of the burns were reduced with the lens.
Dapsone in the Treatment of Presumed Brown Recluse Spider Bite of the Eyelid
Authors: Wesley Ralph E , Ballinger William H , Close L Ward , Lay Allyn M
Published: April 2021

ABSTRACT

Brown recluse spider bites occur commonly in the Southern United States but eyelid bites are rare. Management of eyelid bites is difficult because the initial spider bite is frequently unnoticed, surgical and medical treatments are ineffective, and even a small area of necrosis affects the appearance and function of the eyelid.

Dapsone (4,4,′ diaminodiphenyl sulfone), which inhibits the infiltration of polymorphonuclear leukocytes necessary to mediate the gangrenous skin destruction, has been reported to be effective in treatment of the brown recluse spider bite in both experimental and clinical usage. We report herein a presumed eyelid brown recluse spider bite in which inflammation responded dramatically to treatment with oral Dapsone. Earlier treatment may have prevented eyelid margin necrosis that required reconstruction.
Coumadin Related Spontaneous Hyphemas in Patients With Iris Fixated Pseudophakos
Authors: Schiff Frank S
Published: April 2021

ABSTRACT

Spontaneous hyphemas in iris supported intraocular lenses are considerably more likely to occur in patients on systemic Coumadin therapy. Five cases are presented in which hyphemas appear to be related to Coumadin treatment.
Dehydration of Post-Mortem Eyes for Practice and Experimental Surgery
Authors: Swinger Casimir A , Kornmehl Ernest W
Published: April 2021

ABSTRACT

A technique has been developed that allows for rapid dehydration of the cornea of an intact globe. This technique results in a marked improvement in corneal clarity and visualization of anterior chamber structures. Treated eyes can be used for practice and experimental surgery.