25 results on '"Pallikaris, Ioannis G."'
Search Results
2. A Comparison of Refraction Defects in Childhood Measured Using Plusoptix S09, 2WIN Photorefractometer, Benchtop Autorefractometer, and Cycloplegic Retinoscopy.
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Yalcın E, Sultan P, Yılmaz S, and Pallikaris IG
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- Adolescent, Child, Child, Preschool, Equipment Design, Female, Follow-Up Studies, Humans, Infant, Male, Prospective Studies, Refractive Errors physiopathology, Reproducibility of Results, Mydriatics pharmacology, Refraction, Ocular physiology, Refractive Errors diagnosis, Refractometry instrumentation, Retina diagnostic imaging, Retinoscopy methods, Vision Screening instrumentation
- Abstract
Purpose: To compare Plusoptix (Gmbh, Nuremberg, Germany), 2WIN (Adaptica, Padua, Italy), the benchtop refractometer (Auto-Kerato-Refractometer KR-8900; Topcon Co, Tokyo, Japan), and retinoscopy with regard to the consistencies., Materials and Methods: In our prospective study, 200 eyes of 100 patients were included. We analyzed the demographics and characteristics of the patients, the percentage of patients from whom measurements could not be obtained, the measurements from both patients' eyes of pupil diameter, spherical, cylindrical, axis, and spherical equivalence., Results: The mean age ± SD was 7.8±4.5 years (range, 1-18 years). Pupil diameter measurements were found to be consistent (Cronbach's alpha value >0.8). The sphere and spherical equivalence measurements for both eyes were found to be consistent with each other in all apparatus (Cronbach's alpha value >0.8). However, consistency was found to be lower in cylindrical values and the Jackson cross-cylinder measurements at 0° and 45° axis were found to be inconsistent with each other (Cronbach's alpha value <0.8)., Conclusions: While consistency was observed in all methods in terms of sphere and spherical equivalence, consistency dropped in cylindrical values and no consistency was observed in axis values. It is important to take this point into consideration, especially in axis measurements.
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- 2017
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3. Ocular higher-order aberrations in a school children population.
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Papamastorakis G, Panagopoulou S, Tsilimbaris MK, Pallikaris IG, and Plainis S
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- Adolescent, Analysis of Variance, Astigmatism etiology, Astigmatism pathology, Child, Corneal Wavefront Aberration physiopathology, Female, Greece, Humans, Male, Myopia etiology, Myopia pathology, Refraction, Ocular physiology, Refractive Errors etiology, Corneal Wavefront Aberration pathology, Refractive Errors pathology
- Abstract
Purpose: The primary objective of the study was to explore the statistics of ocular higher-order aberrations in a population of primary and secondary school children., Methods: A sample of 557 children aged 10-15 years were selected from two primary and two secondary schools in Heraklion, Greece. Children were classified by age in three subgroups: group I (10.7±0.5 years), group II (12.4±0.5 years) and group III (14.5±0.5 years). Ocular aberrations were measured using a wavefront aberrometer (COAS, AMO Wavefront Sciences, USA) at mesopic light levels (illuminance at cornea was 4lux). Wavefront analysis was achieved for a 5mm pupil. Statistical analysis was carried out for the right eye only., Results: The average coefficient of most high-order aberrations did not differ from zero with the exception of vertical (0.076μm) and horizontal (0.018μm) coma, oblique trefoil (-0.055μm) and spherical aberration (0.018μm). The most prominent change between the three groups was observed for the spherical aberration, which increased from 0.007μm (SE 0.005) in group I to 0.011μm (SE 0.004) in group II and 0.030μm (SE 0.004) in group III. Significant differences were also found for the oblique astigmatism and the third-order coma aberrations., Conclusions: Differences in the low levels of ocular spherical aberration in young children possibly reflect differences in lenticular spherical aberration and relate to the gradient refractive index of the lens. The evaluation of spherical aberration at certain stages of eye growth may help to better understand the underlying mechanisms of myopia development., (Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.)
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- 2015
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4. Effect of blur and subsequent adaptation on visual acuity using letter and Landolt C charts: differences between emmetropes and myopes.
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Poulere E, Moschandreas J, Kontadakis GA, Pallikaris IG, and Plainis S
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- Adult, Female, Humans, Male, Optometry methods, Vision Tests, Adaptation, Ocular physiology, Emmetropia physiology, Myopia physiopathology, Reading, Refractive Errors physiopathology, Visual Acuity physiology
- Abstract
Purpose: To compare the effects of defocus induced blur and blur adaptation on visual acuity and to evaluate any differences between emmetropes and myopes using letter and Landolt C logMAR charts., Methods: The sample consisted of 26 volunteers, with a mean age of 27 ± 3 years, comprising 13 emmetropes (spherical equivalent range: -0.63 to +0.50 D) and 13 myopes (spherical equivalent range: -0.75 to -5.00 D). Monocular visual acuity (VA) was measured in each eye using letter and Landolt C logMAR charts under the following conditions: (1) with the distance refractive correction, (2) immediately after exposure to +2.00 D defocus and (3) following 60 min of binocular adaptation to +2.00 D blur. Objective refraction at the beginning and at the end of the experimental procedure was evaluated. Averaged VA data between the two eyes were used for analysis., Results: Deterioration in VA with +2.00 D defocus was greater in the emmetropes compared to myopes for both charts. The mean difference between the two refractive groups was more pronounced for the Landolt-C (0.17 logMAR) compared to the letter chart (0.10 logMAR). The reduction in VA with blur was related to the amount of the refractive error. Following 60 min of adaptation, a significant improvement in VA was observed in both groups that did not differ between the two charts. The improvement in VA following adaptation using the letter chart was linearly correlated with spherical equivalent refractive correction., Conclusions: Myopes show higher tolerance to retinal defocus compared to emmetropes, which could be attributed to previous blur experience. The effect of blur on VA is more pronounced using Landolt C optotypes than with letters. Prolonged exposure to blur results in equally improved performance for both refractive groups., (Ophthalmic & Physiological Optics © 2013 The College of Optometrists.)
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- 2013
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5. Long Term Followup of Photorefractive Keratectomy with Adjuvant Use of Mitomycin C.
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Diakonis, Vasilios F., Kankariya, Vardhaman P., Kymionis, George D., Kounis, Georgios, Kontadakis, George, Gkenos, Eirineos, Grentzelos, Michael A., Hajithanasis, George, Yoo, Sonia H., and Pallikaris, Ioannis G.
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ANALYSIS of variance ,REFRACTIVE errors ,INTRAOPERATIVE care ,EVALUATION of medical care ,T-test (Statistics) ,RETROSPECTIVE studies ,DATA analysis software ,DESCRIPTIVE statistics ,PHOTOREFRACTIVE keratectomy ,MITOMYCINS - Abstract
Purpose. To study the long term refractive and visual outcomes of photorefractive keratectomy (PRK) with intraoperative application of mitomycin C (MMC). Methods. This study included 37 eyes who received myopic PRK; after photoablation, a sponge soaked in 0.02% MMC solution was applied in all corneas for 2 minutes. Efficacy, safety, predictability, and stability of PRK MMC were evaluated. Endothelial cell density was evaluated at the last postoperative interval. Results. Mean preoperative spherical equivalent (SEQ) was -6.03 ± 1.87 D (diopters) and reduced to -0.09 ± 0.53 D at the last postoperative examination. Mean followup was 44.73 ± 18.24 months. All the eyes were in the ±1.00 D of attempted versus achieved SEQ at the one-year follow-up interval. Furthermore, 95% of the eyes did not lose lines or gained 1 to 2 lines of CDVA, while 5% lost 1 line. At the third postoperative month, 89% of the eyes either were clear or had trace haze, while 4 eyes had mild haze; by the 12-month postoperative interval, none of the eyes demonstrated haze. Mean endothelial cell density (ECD) at the last postoperative interval was 2658 ± 153 cells/mm². Conclusions. PRK, with intraoperative use of MMC, demonstrates stable refractive and visual outcomes up to 44 months after surgery. [ABSTRACT FROM AUTHOR]
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- 2014
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6. Long-term Results of Phakic Refractive Lens Implantation in Eyes With High Myopia.
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Portaliou, Dimitra M., Kymionis, George D., Panagopoulou, Sophia I., Kalyvianaki, Maria I., Grentzelos, Michael A., and Pallikaris, Ioannis G.
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INTRAOCULAR lenses ,MYOPIA ,REFRACTIVE errors ,VISUAL acuity ,EYE diseases - Abstract
Purpose: To evaluate the long-term results of phakic refractive lens (PRL; Carl Zeiss Meditec) implantation in eyes with high myopia. Methods: In this retrospective, noncomparative, interventional case series, 143 myopic eyes of 82 patients were treated for high myopia with the implantation of the silicone PRL in the posterior chamber. Results: Mean follow-up was 3.8±1.7 years (range: 1 to 6 years). Six years postoperatively (n=34), a statistically significant reduction was noted in the cycloplegic spherical equivalent from −14.08±4.00 diopters (D) (range: −24.88 to −4.75 D) before PRL implantation to −0.45±0.62 D (range: −1.00 to 1.00 D) (P<.001). At 6 years, 67.6% (23 eyes) and 91.2% (31 eyes) were within ±0.50 and ±1.00 D of target refraction, respectively. Mean logMAR uncorrected and corrected distance visual acuity improved significantly (P<.001) (counting fingers preoperatively in all eyes to 0.17±0.15 [range: 0.54 to −0.06] and 0.19±0.19 [1.00 to −0.08] to 0.07±0.10 [range: 0.30 to −0.10], respectively). Complications included anterior capsule damage (3 eyes), temporary intraocular pressure increase (14 eyes), pigment dispersion (1 eye), and PRL decentration (1 eye). No eyes presented any signs of cataract up to 6 years postoperatively. Conclusions: Long-term results show that PRL implantation is an effective and safe method for treating high myopia. [ABSTRACT FROM AUTHOR]
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- 2011
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7. Myopia and visual acuity impairment: a comparative study of Greek and Bulgarian school children.
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Plainis, Sotiris, Moschandreas, Joanna, Nikolitsa, Panagoula, Plevridi, Eleani, Giannakopoulou, Trisevgeni, Vitanova, Vania, Tzatzala, Paraskevi, Pallikaris, Ioannis G., and Tsilimbaris, Miltiadis K.
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REFRACTIVE errors ,VISION disorders ,MYOPIA ,VISUAL acuity ,HEALTH of school children - Abstract
Purpose: To compare the proportions of school children with myopia and impaired visual acuity in Greece and Bulgaria. Methods: A sample of 898 children, aged 10–15 years, was selected from two primary and two secondary schools in a Greek city (Heraklion), and one primary and secondary school in a Bulgarian city (Stara Zagora). Five hundred and eighty eight children were Greek (65.5%, mean age 12.5 ± 0.08 years) and 310 Bulgarian (34.5%, age 12.4 ± 0.07 years). VA was assessed with the habitual refractive correction. Refractive error was measured in the absence of cycloplegia using an auto-refractor. Results: The percentage of children, tested with their habitual refractive correction, with decimal VA <0.5 in at least one eye was 11.7% (95% CI 9.1–14.3%) for Greek and 5.2% (95% CI 2.7–7.6%) for Bulgarian pupils. The percentage of myopic children also differed between the two countries with the proportion with myopic refractive error ≤−0.75 D and decimal VA <0.8 at primary school level being 14.1% and 28.9% in Stara Zagora and Heraklion respectively and 13.0% and 46.9% (95% CI 18.2–29.2%, p < 0.0001) at secondary school level. Among the myopic pupils only 35.8% used corrective spectacles in Stara Zagora, compared to 70.7% of the children in Heraklion. Finally, myopia appeared more prevalent in female adolescents with the effect being statistically significant only for Greek children (55% vs 40% of males, p = 0.015). Conclusions: The increased proportion of myopic children in Heraklion, compared to Stara Zagora, may arise from a number of environmental and socio-economic factors, which need to be further investigated in order to understand the differences observed among European populations. [ABSTRACT FROM AUTHOR]
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- 2009
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8. Epi-LASIK: Histological Findings of Separated Epithelial Sheets 24 Hours After Treatment.
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Katsanevaki, Vikentia J., Naoumidi, Irini I., Kalyvianaki, Maria I., and Pallikaris, Ioannis G.
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LASIK ,MYOPIA ,REFRACTIVE errors ,ELECTRON microscopy ,EPITHELIAL cells ,CELL morphology - Abstract
PURPOSE: To report the histological findings of four eyes of three patients who underwent epi-LASIK treatment for the correction of low myopia. METHODS: The epithelial sheets were harvested either immediately after separation (one eye) or were accidentally dislocated and harvested from the operative eyes 24 hours after treatment (three eyes). All sheets underwent optical and transmission electron microscopy. RESULTS: Histological evaluation showed that the majority of the epithelial cells were morphologically normal in all examined specimens. CONCLUSIONS: Histological examination of specimens in four eyes showed that 24 hours after mechanical separation the epithelial cells' morphology was close to normal. [ABSTRACT FROM AUTHOR]
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- 2006
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9. Long-term results of conductive keratoplasty for low to moderate hyperopia
- Author
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Pallikaris, Ioannis G., Naoumidi, Tatiana L., and Astyrakakis, Nikolaos I.
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REFRACTIVE errors , *HYPEROPIA , *CORNEA surgery , *VISUAL acuity - Abstract
Purpose: To assess the long-term safety, efficacy, predictability, and stability of conductive keratoplasty (CK) for the treatment of low to moderate hyperopia and to evaluate the impact of the procedure on the quality of vision. Setting: University of Crete, Medical School, Vardinoyannion Eye Institute of Crete, Crete, Greece. Methods: In this prospective nonrandomized noncontrolled single-center study, 38 eyes of 26 patients (13 women and 13 men) were treated for hyperopia with a Refractec ViewPoint CK system and followed for 30 months. Preoperatively, the mean manifest refraction spherical equivalent (MRSE) was +1.89 diopters (D) ± 0.6 (SD) (range +1.00 to +3.25 D), and the mean follow-up was 30.9 ± 1.1 months. All eyes were treated with the regular CK nomogram for the treatment of spherical hyperopia. The treatment consisted of 8 to 32 spots applied to the periphery of the cornea. Mean age was 50.3 ± 8.8 years (range 31 to 71 years). All treated eyes were analyzed for safety, efficacy, predictability, and stability. Results: At 12 months, the MRSE was −0.06 ± 0.8 D and at 30 months was −0.02 ± 0.7 D. At 30 months, the mean MRSE was within ±0.50 D in 68%, within ±1.00 D in 92%, and within ±2.00 D in all eyes. At 30 months, uncorrected visual acuity was 20/20 or better in 52.5% and 20/40 or better in 89% of eyes. No eye lost 2 or more Snellen lines or had an induced cylinder of 2.00 D or greater. The procedure did not cause statistically significant changes in contrast sensitivity. Conclusion: Results show that CK for low to moderate hyperopia is a safe, effective, predictable, and stable procedure. [Copyright &y& Elsevier]
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- 2005
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10. Epi-LASIK: Preliminary clinical results of an alternative surface ablation procedure
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Pallikaris, Ioannis G., Kalyvianaki, Maria I., Katsanevaki, Vikentia J., and Ginis, Harilaos S.
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REFRACTIVE errors , *EYE care , *MYOPIA , *PATIENTS - Abstract
Purpose: To evaluate the clinical results of epi-LASIK, a new surface ablation surgical technique for the treatment of low myopia. Setting: Vardinoyannion Eye Institute of Crete, University of Crete, Greece. Methods: Forty-four eyes of 31 patients had epi-LASIK for the correction of low myopia. Mean preoperative spherical equivalent was 3.71 diopters (D) ± 1.2 (SD) (range −1.75 to −7.00 D) and the mean baseline logMAR best spectacle-corrected visual acuity was −0.01 ± 0.06 (range 0.10 to −0.10). All the epithelial separations were performed with the Centurion epikeratome (CIBA Surgical). The enrolled patients were followed daily until the epithelial healing was complete as well as at 1- and 3-month intervals. On the operative day, patients filled out a questionnaire grading visual performance and pain score of treated eyes every 2 hours for a total of 5 records. Results: The mean epithelial healing time was 4.86 ± 0.56 days (range 3 to 5 days). The mean logMAR uncorrected visual acuity on the day of reepithelization was 0.19 ± 0.09 (range 0.40 to 0.10). At 1 month, the mean was spherical equivalent of the treated eyes (N=44), −0.3 ± 0.6 D (range −1.0 to 0.87 D), and at 3 months it was (N=37), −0.10 ± 0.4 D (range −0.75 to 0.75 D); 97% of eyes had clear corneas or trace haze 3 months after treatment. Conclusions: Preliminary clinical results suggest that epi-LASIK is a safe and efficient method for the correction of low myopia. Further studies will establish this method as an alternative surface ablation procedure. [Copyright &y& Elsevier]
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- 2005
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11. Intraocular Pressure Measurements After Conductive Keratoplasty.
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Kymionis, George D., Naoumidi, Tatiana L., Aslanides, Ioannis M., Kumar, Vinod, Astyrakakis, Nikolaos I., Tsilimbaris, Miltiadis, and Pallikaris, Ioannis G.
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INTRAOCULAR pressure ,CORNEA surgery ,REFRACTIVE errors ,OPHTHALMIC surgery ,HYPEROPIA - Abstract
PURPOSE: To determine the possible impact of conductive keratoplasty (CK) on intraocular pressure (IOP) measurements. METHODS: A prospective, single-center, noncomparative interventional case series was performed. Baseline and postoperative IOPs were measured by Goldmann applanation tonometry in 32 eyes of 18 patients who underwent CK for hyperopia correction. Mean follow-up was 11.9 months (range: 8 to 18 months). RESULTS: After CK, a statistically significant decrease in the measured IOP was observed (before CK: 14.22±1.64 vs after CK: 12.66±2.21, P<.001). The change in IOP readings postoperatively was not correlated with age, sex, keratometric readings, or attempted correction. CONCLUSIONS: Despite the limitations due to the small number of patients enrolled in this study, the applanation tonometer appears to underestimate the true IOP after CK. [ABSTRACT FROM AUTHOR]
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- 2005
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12. Conductive Keratoplasty for Low to Moderate Hyperopia: 1-year Results.
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Pallikaris, Ioannis G., Naoumidi, Tatiana L., Panagopoulou, Sophia I., Alegakis, Athanasios K., and Astyrakakis, Nikolaos I.
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OPHTHALMIC surgery ,HYPEROPIA ,REFRACTIVE errors ,CORNEA surgery ,LASIK - Abstract
PURPOSE: To assess the safety, efficacy, and stability of conductive keratoplasty in the treatment of low to moderate hyperopia and evaluate the impact of the procedure on the quality of vision. METHODS: Thirty-six eyes (25 patients; 13 female and 12 male) were treated for hyperopia up to +3.25 D with a Refractec ViewPoint CK system and followed for 1 year. Mean age was 50.2 ± 8.7 years (range 31 to 71). RESULTS: Before surgery, mean spherical equivalent refraction was +1.90 ± 0.60 D (range +1.00 to +3.25 D), decreasing at 1 year after conductive keratoplasty to -0.06 ± 0.80 D, and was within ±0.50 D of emmetropia in 68% (24 eyes) and within ±2.00 D in all eyes. Twelve months after conductive keratoplasty, uncorrected visual acuity was 20/20 or better in 19 eyes (50%) and 20/40 or better in 32 eyes (89%). No eye lost ≥2 Snellen lines or had induced cylinder ≥2.00 D. The mean root mean square values for higher order optical aberrations were 0.060 ± 0.039 before and 0.174 ± 0.170 at 3 months after surgery. No statistically significant changes in contrast sensitivity were noted. CONCLUSIONS: Conductive keratoplasty for low to moderate hyperopia provided safe, effective, and stable results both in refraction and quality of vision. [ABSTRACT FROM AUTHOR]
- Published
- 2003
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13. Influence of Ablation Parameters on Refractive Changes After Phototherapeutic Keratectomy.
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Ginis, Harilaos S., Katsanevaki, Vikentia J., and Pallikaris, Ioannis G.
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REFRACTIVE errors ,CORNEA laser surgery ,OPTICAL aberrations ,VISION disorders ,LASER surgery ,OPHTHALMIC surgery - Abstract
PURPOSE: The aim of the current study was to control the hypothetical effects of decreased laser energy delivered to the peripheral cornea during phototherapeutic keratectomy (PTK) and provide quantitative calculation of induced low and high order aberrations. METHODS: We employed a model eye to simulate the refractive effect of homogeneous laser corneal irradiation, as in PTK, for different laser fluences (range 125 to 225 mJ/cm²) and treatment depths up to 200 µm. RESULTS: The hyperopic shift induced by the relatively lower energy delivered at the peripheral ablation zone during PTK was proportional to the treatment depth and inversely proportional to the energy fluence. The hyperopic shift calculated using the above ablation parameters was lower compared to previously reported clinical results. Higher order wavefront aberration (total root mean square) changes were of minimal significance for treatment depths up to 200 µm. CONCLUSIONS: After PTK, a hyperopic shift cannot be attributed to the energy delivery method alone. Modification of laser energy delivery algorithms may only minimize PTK-induced hyperopia. [ABSTRACT FROM AUTHOR]
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- 2003
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14. Induced optical aberrations following formation of a laser in situ keratomileusis flap
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Pallikaris, Ioannis G., Kymionis, George D., Panagopoulou, Sophia I., Siganos, Charalambos S., Theodorakis, Michalis A., and Pallikaris, Aristofanis I.
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OPTICAL aberrations , *REFRACTIVE errors - Abstract
: PurposeTo determine how refractive error, visual acuity, and high-order aberrations (3rd- and 4th-order) are affected by the formation of a lamellar corneal flap during laser in situ keratomileusis (LASIK).: SettingUniversity refractive surgery center.: MethodsThe effect of lamellar corneal flap formation was analyzed in 15 myopic eyes (mean preoperative refraction −4.72 diopters [D] [range −1.25 to −7.25 D]). The flap was created using a 2-step procedure: (1) a nasally hinged lamellar corneal flap was created; (2) the flap was lifted and stromal ablation performed 2 months after the flap was made. A Hartmann-Shack aberrometer was used to measure the aberrations.: ResultsThere was no significant change in the refractive error (spherical equivalent pre-flap −4.72 ± 1.99 D and post-flap −4.62 ± 1.99 D [P = .28]) or visual acuity (pre-flap uncorrected visual acuity [UCVA] 0.07 and best corrected visual acuity [BCVA] 0.96; post-flap UCVA 0.08 and BCVA 0.95 [P = .16 and P = .33, respectively]). A statistically significant increase in total higher-order wavefront aberrations was observed following flap formation (root mean square pre-flap 0.344 ± 0.125 and post-flap 0.440 ± 0.221 [P = .04]).: ConclusionFlap formation during LASIK can modify the eye’s existing natural higher-order aberrations (especially spherical and coma-like aberrations along the axis of the flap’s hinge), while visual acuity and refractive error remain unaffected. [Copyright &y& Elsevier]
- Published
- 2002
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15. Fifteen-Year Follow-up After Anterior Chamber Phakic Intraocular Lens Implantation in One and LASIK in the Fellow Eye.
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Kymionis, George D., Grentzelos, Michael A., Kalyvianaki, Maria I., Detorakis, Efstathios T., Kounis, George A., Tsilimbaris, Miltiadis K., and Pallikaris, Ioannis G.
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CORNEA laser surgery ,LASIK ,EYE care ,REFRACTIVE errors ,INTRAOCULAR lenses ,VISUAL acuity - Abstract
Purpose: To report a patient fifteen years after anterior chamber phakic intraocular lens (AC-PIOL) implantation in one and laser in situ keratomileusis (LASIK) in the fellow eye. Methods: Case report. Results: A 56-year-old male underwent AC-PIOL implantation in one eye and LASIK in the fellow eye fifteen years ago. Preoperative uncorrected visual acuity (UCVA) was finger count in both eyes. Preoperative best spectacle-corrected visual acuity (BSCVA) was 20/25 (−16.75 −0.50 × 40) in the LASIK eye and 20/32 (−24.50 −0.50 × 90) in the AC-PIOL eye. Fifteen years postoperatively, UCVA was finger count in the LASIK eye and 20/200 in the AC-PIOL eye, while BSCVA was 20/32 and 20/25, respectively. Endothelial cell density (ECD) was 2020±47 in the LASIK eye and 945±22 in the AC-PIOL eye. Conclusion: Both procedures had similar visual outcomes. Furthermore, lower ECD was found in the AC-PIOL eye in comparison to the LASIK eye. [ABSTRACT FROM AUTHOR]
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- 2009
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16. Photorefractive Keratectomy in a Patient with Epithelial Basement Membrane Dystrophy.
- Author
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Kymionis, George D., Diakonis, Vasillios F., Bouzoukis, Dimitrios I., Yoo, Sonia H., and Pallikaris, Ioannis G.
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PHOTOREFRACTIVE materials ,DYSTROPHY ,RETINAL degeneration ,EPITHELIUM ,REFRACTIVE errors ,VISION disorders - Abstract
Purpose: To report a case of excimer laser photorefractive keratectomy (PRK) in a patient with epithelial basement membrane dystrophy (EBMD). Methods: Interventional case report. Results: A 36-year-old male with clinical manifestations of EBMD underwent bilateral, simultaneous PRK for low myopia correction. A delay (up to 17 days) in the epithelial healing process with unstable epithelium was observed. During the first three postoperative months a visually significant subepithelial haze was developed in both eyes. One year postoperative, an improvement in haze formation and visual acuity in both eyes was found. Conclusions: PRK in patients with EBMD could result in favorable refractive and clinical outcome. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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17. Laser in situ Keratomileusis for Residual Hyperopic Astigmatism After Conductive Keratoplasty.
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Kymionis, George D., Aslanides, Ioannis M., Khoury, Aghlab N., Markomanolakis, Marinos M., Naoumidi, Tatiana, and Pallikaris, Ioannis G.
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LASIK ,CORNEA laser surgery ,REFRACTIVE errors ,REFRACTION (Optics) ,OPHTHALMOLOGY - Abstract
PURPOSE: To report a case of laser in situ keratomileusis (LASIK) in a patient with previous conductive keratoplasty. METHODS: A 48-year-old man underwent conductive keratoplasty for low hyperopic astigmatism (manifest refraction OD: +2.25 -0.50 x 77°; OS: +2.50 -0.50 x 105°). Three months postoperatively, UCVA was 20/25 and BSCVA was 20/20 in both eyes; manifest refraction OD: -0.25 -0.75 x 110°; OS: +0.75 -0.75 x 50°. Sixteen months after the operation, regression of refractive outcome was (manifest) OD: +1.75 -1.25 x 90°; OS: +2.50 -0.50 x 85°; UCVA was 20/40 in the right eye and 20/63 in the left eye and BSCVA was 20/20 in both eyes. LASIK was performed for hyperopic regression in the left eye using an automated microkeratome (Alcon SKBM, 130-µm plate; Aesculap-Meditec MEL 70 excimer laser). RESULTS: LASIK was uneventful and no intraoperative or postoperative complications related to the previous conductive keratoplasty procedure or LASIK were observed. Three months after LASIK and 19 months after the initial conductive keratoplasty, the patient's left eye was emmetropic; UCVA was 20/20
-2 , BSCVA was 20/20 and manifest refraction was +0.25 -0.25 x 35°. There was a uniform increase in topographical steepening. Visual acuity, refraction and topographic findings remained unchanged at 6 months. CONCLUSIONS: Even though our experience is limited, treatment of hyperopia with LASIK in an eye with refractive regression following previous conductive keratoplasty resulted in a predicted refractive outcome, with no complications, and improvement in visual acuity at 6 months followup. [ABSTRACT FROM AUTHOR]- Published
- 2004
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18. Ocular rigidity may affect corneal biomechanics after refractive surgery.
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Pallikaris, Ioannis G.
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EYE examination , *EYE care , *OPHTHALMIC surgery , *LASIK , *CORNEA laser surgery , *REFRACTIVE errors - Abstract
The article focuses on the research findings that ocular rigidity may affect corneal biomechanics after a refractive surgery. According to professor and chairman of the department of ophthalmology Ioannis G. Pallikaris, MD at the University Hospital in Heraklion, total eye rigidity is one of the major factors that affect the biomechanics of the cornea. He added, with the LASIK the thickness of the cornea decreased and the radius of the cornea in myopic eyes increases.
- Published
- 2006
19. Effect of excimer laser repetition rate on outcomes after photorefractive keratectomy
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Kymionis, George D., Diakonis, Vasilios F., Kounis, George, Bouzoukis, Dimitrios I., Gkenos, Eirineos, Ginis, Harilaos, Yoo, Sonia H., and Pallikaris, Ioannis G.
- Subjects
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REFRACTIVE errors , *MYOPIA , *VISION disorders , *EXCIMER lasers - Abstract
Purpose: To compare the refractive outcomes after photorefractive keratectomy (PRK) for low to moderate myopic corrections using 2 excimer lasers with different repetition rates (200 Hz and 400 Hz). Setting: University refractive surgery center. Methods: This retrospective study included all consecutive patients who underwent PRK using the 200 Hz or the 400 Hz Allegretto laser platform (WaveLight Laser Technologie AG). Thirty-five patients (70 eyes) and 29 patients (58 eyes) had PRK with the 200 Hz platform and the 400 Hz platform, respectively, using the same surgical technique. Results: The mean follow-up was 13.22 months ± 1.16 (SD) (range 11 to 15 months). No intraoperative or early postoperative (eg, late reepithelialization) complications were found in either group. At 1 year, 66 eyes (94.2%) in the 200 Hz group and 56 eyes (96.6%) in the 400 Hz group were within ±1.00 diopter of the attempted correction. At 3 months, 20 eyes (29%) in the 200 Hz group and 27 eyes (46%) in the 400 Hz group had mild or moderate corneal haze (P = .03). These corneas showed progressive clearing over subsequent months without statistically significant differences in haze formation between the 2 groups. Twelve months after PRK, all corneas in both groups were clear. Conclusion: Photorefractive keratectomy for the treatment of low to moderate refractive errors using a 200 Hz or 400 Hz excimer laser gave comparable results. [Copyright &y& Elsevier]
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- 2008
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20. Endothelial cell density after photorefractive keratectomy for moderate myopia using a 213 nm solid-state laser system
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Tsiklis, Nikolaos S., Kymionis, George D., Pallikaris, Aristofanis I., Diakonis, Vasilios F., Ginis, Harilaos S., Kounis, George A., Panagopoulou, Sophia I., and Pallikaris, Ioannis G.
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REFRACTIVE errors , *CONFOCAL microscopy , *CORNEAL topography , *OPHTHALMIC surgery - Abstract
Purpose: To evaluate whether photorefractive keratectomy (PRK) for moderate myopia using a solid-state laser with a wavelength of 213 nm alters the corneal endothelial cell density. Setting: University refractive surgery center. Methods: The corneal endothelium was analyzed preoperatively and 1, 6, and 12 months postoperatively using corneal confocal microscopy (modified HRT II with a Rostock Cornea Module, Heidelberg Engineering) in 60 eyes (30 patients). Patients were randomized to have myopic PRK using a 213 nm wavelength solid-state laser (study group) or a conventional 193 nm wavelength excimer laser (control group). Three endothelial images were acquired in each of 30 preoperative normal eyes to evaluate the repeatability of endothelial cell density measurements. Repeated-measures analysis of variance was used to compare the variations in endothelial cell density between the 2 lasers and the changes in endothelial cell density over time. Results: There were no statistically significant differences in sex, age, corneal pachymetry, attempted correction, preoperative endothelial cell density, or postoperative refractive outcomes (uncorrected visual acuity, best spectacle-corrected visual acuity, and spherical equivalent refraction) between the 2 groups (P>.05). The coefficient of repeatability of endothelial cell density was 131 cells/mm2. The measured endothelial cell count per 1.0 mm2 did not significantly change up to 1 year postoperatively in either group (both P>.05). No statistically significant difference was found between the 2 groups in any postoperative interval (P>.05). Conclusion: Photorefractive keratectomy for moderate myopia using a 213 nm wavelength solid-state laser or a conventional 193 nm wavelength excimer laser did not significantly affect corneal endothelial density during the 1-year postoperative period. [Copyright &y& Elsevier]
- Published
- 2007
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21. Long-term results of superficial laser in situ keratomileusis after ultrathin flap creation
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Kymionis, George D., Tsiklis, Nikolaos, Pallikaris, Aristofanis I., Diakonis, Vassilios, Hatzithanasis, George, Kavroulaki, Dimitra, Jankov, Mirko, and Pallikaris, Ioannis G.
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EYE care , *REFRACTIVE errors , *OPHTHALMIC surgery , *VISUAL acuity - Abstract
Purpose: To study the long-term efficacy, safety, and stability of laser in situ keratomileusis (LASIK) after unintentional ultrathin flap creation less than 80 μm. Setting: University refractive surgery center. Methods: This retrospective case series comprised 25 patients (33 eyes) who had LASIK after flap creation less than 80 μm with the Moria M2 disposable microkeratome (head 90 μm). Flap thickness was measured with intraoperative ultrasound pachymetry. Manifest refraction, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity, predictability, stability, complications, patient satisfaction, and confocal microscopy images were studied. Results: The mean follow-up was 14.58 months ± 3.73 (SD) (range 12 to 25 months). The mean flap thickness was 72.1 ± 5.9 μm (range 58 to 80 μm), and the mean preoperative spherical equivalent (SE) refraction was –5.59 ± 2.01 diopters (D) (range −10.25 to −3.25 D). On the first postoperative day, the UCVA was 20/25 or better. The SE manifest refraction was 1.00 D or less in all patients. The mean SE manifest refraction was −0.75 ± 0.55 D (range −1.00 to +0.75 D) (P<.01). At the last follow-up, changes in visual acuity and manifest refraction were not statistically significant; no late postoperative complications were observed. All patients were satisfied with the final outcome. Qualitative analysis of confocal microscopy images revealed interface particles and activated keratocytes. Conclusions: Despite the small sample and retrospective nature of the study, superficial LASIK seemed to be a safe and predictable technique for myopic refractive corrections. Patients were satisfied with the results and had rapid visual recovery with no intraoperative or early or late postoperative complications. If the safety and efficacy of an ultrathin flap are confirmed by additional studies, superficial LASIK could represent a new approach that combines the advantages of surface and lamellar procedures. [Copyright &y& Elsevier]
- Published
- 2006
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22. Two-year follow-up of conductive keratoplasty for the treatment of hyperopic astigmatism
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Naoumidi, Tatiana L., Kounis, George A., Astyrakakis, Nikolaos I., Tsatsaronis, Dimitrios N., and Pallikaris, Ioannis G.
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REFRACTIVE errors , *CORNEA surgery , *ASTIGMATISM , *VISUAL acuity - Abstract
Purpose: To evaluate the safety, efficacy, predictability, and stability of conductive keratoplasty (CK) for the treatment of hyperopic astigmatism. Setting: University of Crete Medical School, Vardinoyannion Eye Institute of Crete, Heraklion, Greece. Methods: In this prospective nonrandomized noncontrolled single-center study, 47 eyes of 34 patients (15 women and 19 men) were treated for hyperopic astigmatism (up to + 3.50 diopters [D]) with a Refractec ViewPoint CK system and followed for 24 months ± 0.6 (SD). The treatment consisted of 4 to 36 spots applied to the periphery of the cornea. Mean age was 48.5 years ± 9.7 years, range 25 to 68 years. All the treated eyes were analyzed for safety, efficacy, predictability, and stability. Results: The mean patient age was 48.5 ± 9.7 years (range 25 to 68 years). Preoperatively, the mean manifest refraction spherical equivalent (MRSE) was +2.11 ± 0.88 D (range −0.50 to + 4.13 D); at 12 months, it was −0.52 ± 0.73 D and at 24 months, −0.50 ± 0.77 D. At 24 months, the mean MRSE was within ±0.50 D in 61% of eyes, within ±1.00 D in 83%, and within ±2.00 D in all eyes. At 24 months, the uncorrected visual acuity was 20/20 or better in 37% of eyes and 20/40 or better in 97%. By the end of the follow-up period, no eye had lost ≥2 Snellen lines or had an induced cylinder ≥1.50 D. Conclusions: Conductive keratoplasty for low hyperopic astigmatism was a safe, effective, and stable procedure. Nomogram adjustments and careful patient selection should contribute to higher levels of predictability when treating hyperopic astigmatism. [Copyright &y& Elsevier]
- Published
- 2006
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23. Intraoperative Management of Partial Flap during LASIK: A Small Case Series Report
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Katsanevaki, Vikentia J., Tsiklis, Nikolaos S., Astyrakakis, Nikolaos I., and Pallikaris, Ioannis G.
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EYE care , *REFRACTIVE errors , *PATIENTS , *HEALTH outcome assessment - Abstract
Purpose: To report the intraoperative management of incomplete microkeratome LASIK flaps. Design: Small, retrospective, noncomparative, interventional case series. Participants: Five outpatients. Methods: In 5 eyes of 5 patients, the premature stop of the microkeratome resulting from mechanical obstacles resulted in an incomplete flap that would not allow for the completion of the LASIK procedure. After the careful realignment of the partial flaps and the removal of the identified obstacles, the second pass of the microkeratome resulted in flaps of the intended size. Main Outcome Measures: Final creation of a flap as intended, completion of the procedure, and visual and refractive outcome of the operative eyes. Results: The second pass of the microkeratome resulted in flaps as planned. All the procedures were completed, and the operative eyes that were followed up for at least 3 months had excellent visual and refractive results. Conclusions: The second pass of the microkeratome can successfully manage incomplete flaps resulting from microkeratome premature stop as a result of mechanical obstacles. [Copyright &y& Elsevier]
- Published
- 2005
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24. Topographically supported customized ablation for the management of decentered laser in situ keratomileusis
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Kymionis, George D., Panagopoulou, Sophia I., Aslanides, Ioannis M., Plainis, Sotiris, Astyrakakis, Nikolaos, and Pallikaris, Ioannis G.
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REFRACTIVE errors , *VISUAL acuity , *EYE care , *SURGICAL complications - Abstract
: PurposeTo evaluate the efficacy, predictability, and safety of topographically supported customized ablations (TOSCAs) for decentered ablations following laser in situ keratomileusis (LASIK).: DesignProspective nonrandomized clinical trial.: MethodsNine patients (11 eyes) with LASIK-induced decentered ablations underwent TOSCA following flap lifting. Topographically supported customized ablation was performed using a corneal topographer to obtain a customized ablation profile, combined with a flying spot laser.: ResultsMean follow-up was 9.22 ± 2.82 months (range 6–12 months). No intra- or postoperative complications were observed. Manifest refraction (spherical equivalent) did not change significantly (pre-TOSCA: −0.14 ± 1.58 diopters [range, –1.75 to +3.00 diopters] to +0.46 ± 1.02 diopters [range, −1.00 to +1.75 diopters]; P = .76), whereas there was a statistically significant reduction in the refractive astigmatism (pre-TOSCA: –1.55 ± 0.60 diopters [range, −3.00 to −0.75 diopters] to –0.70 ± 0.56 diopters [range, −2.00 to −0.25 diopters]; P = .003). Mean uncorrected visual acuity improved significantly (P < .001) from 0.45 ± 0.16 (range, 0.2–0.7) to 0.76 ± 0.29 (range, 0.2–1.2) at last follow-up. Mean best-corrected visual acuity improved from 0.74 ± 0.22 (range, 0.4–1.0) to 0.95 ± 0.20 (range, 0.6–1.2; P = .002). Eccentricity showed a statistically significant reduction after TOSCA treatment (pre-TOSCA: 1.59 ± 0.46 mm [range, 0.88–2.23 mm]; post-TOSCA: 0.29 ± 0.09 mm [range, 0.18–0.44 mm]; P < .001).: ConclusionIn our small sample, enhancement LASIK procedures with TOSCA appear to improve uncorrected and best-corrected visual acuity as well as eccentricity in patients with LASIK-induced decentered ablation. [Copyright &y& Elsevier]
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- 2004
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25. Comparison of Corneal Sensitivity and Tear Function Following Epi-LASIK or Laser In Situ Keratomileusis for Myopia
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Kalyvianaki, Maria I., Katsanevaki, Vikentia J., Kavroulaki, Dimitra S., Kounis, George A., Detorakis, Efstathios T., and Pallikaris, Ioannis G.
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REFRACTIVE errors , *EYE care , *MEDICAL experimentation on humans , *MEDICAL research - Abstract
Purpose: To compare the effect of Epi-LASIK or Laser In Situ Keratomileusis (LASIK) on corneal sensitivity and tear function. Design: Prospective, non-randomized comparative clinical trial. Methods: Seventy-nine eyes (Group A) underwent Epi-LASIK and 61 eyes underwent LASIK (Group B) for the treatment of myopia. Matching parameters between the groups were age and attempted correction. Corneal sensitivity, tear break-up time (BUT), and Schirmer test II were evaluated before and at one, three, and six months after the procedure. Results: Corneal sensitivity and BUT were decreased at one month in Group A (P < .001) to be restored by the third month (P = .71 and P = .58, respectively). In Group B, corneal sensitivity and BUT were reduced postoperatively (P < .001). There was a significant difference in corneal sensitivity between the two groups at all postoperative intervals. Schirmer test II was not significantly decreased postoperatively in Group A. In Group B, it was decreased at one and three months and restored by the sixth month. Conclusion: Epi-LASIK-treated eyes had faster rehabilitation of corneal sensitivity and tear function than LASIK-treated eyes. [Copyright &y& Elsevier]
- Published
- 2006
- Full Text
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