SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: Journal of cataract and refractive surgery

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PURPOSE: To explore the use of the Pulsar Z1 solid-state 213 nm photorefractive laser platform in topography-guided transepithelial photorefractive keratectomy (PRK) for irregular astigmatism. SETTING: Moorfields Eye Hospital, London, United Kingdom. DESIGN: Prospective clinical case series. METHODS: Patients with irregular astigmatism after previous refractive surgery or corneal transplantation were treated with topography-guided transepithelial PRK. Preoperatively and 1-year postoperatively, corrected distance visual acuity (CDVA) and secondary outcome measures (including manifest refraction, contrast sensitivity, haze score, index of surface variation, root-mean-square higher-order aberrations, and subjective visual change) were compared between groups. Adjunctive mitomycin-C was not used. RESULTS: Seven patients had previous refractive surgery, and 7 had previous corneal transplantation. All but 2 patients with a marked haze response had subjective gains in vision and improved CDVA. Gains in CDVA for patients with irregular astigmatism after previous refractive surgery (median 2 lines gain; range 0 to 2 lines gained) were higher than for patients with irregular astigmatism after keratoplasty (median 0 lines; range 5 lines lost to 4 lines gained). Trends in secondary outcome measures were similar, with greater variation in post-keratoplasty patients. Haze scores were higher in post-keratoplasty patients. CONCLUSIONS: 213 nm topography-guided transepithelial PRK was easy to perform and well tolerated by patients with irregular astigmatism. Most patients gained CDVA; however, increased haze responses were observed in post-keratoplasty cases. FINANCIAL DISCLOSURE: Neither author has a financial or proprietary interest in any material or method mentioned.

Concepts: Surgery, Laser, Visual acuity, Cornea, Ophthalmology, LASIK, Keratoconus, Photorefractive keratectomy

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PURPOSE: To assess the intrasession and intersession precision of ocular, corneal, and internal higher-order aberrations (HOAs) measured using an integrated topographer and Hartmann-Shack wavefront sensor (Topcon KR-1W) in refractive surgery candidates. SETTING: IOBA-Eye Institute, Valladolid, Spain. DESIGN: Evaluation of diagnostic technology. METHODS: To analyze intrasession repeatability, 1 experienced examiner measured eyes 9 times successively. To study intersession reproducibility, the same clinician obtained measurements from another set of eyes in 2 consecutive sessions 1 week apart. Ocular, corneal, and internal HOAs were obtained. Coma and spherical aberrations, 3rd- and 4th-order aberrations, and total HOAs were calculated for a 6.0 mm pupil diameter. RESULTS: For intrasession repeatability (75 eyes), excellent intraclass correlation coefficients (ICCs) were obtained (ICC >0.87), except for internal primary coma (ICC = 0.75) and 3rd-order (ICC = 0.72) HOAs. Repeatability precision (1.96 × S(w)) values ranged from 0.03 μm (corneal primary spherical) to 0.08 μm (ocular primary coma). For intersession reproducibility (50 eyes), ICCs were good (>0.8) for ocular primary spherical, 3rd-order, and total higher-order aberrations; reproducibility precision values ranged from 0.06 μm (corneal primary spherical) to 0.21 μm (internal 3rd order), with internal HOAs having the lowest precision (≥0.12 μm). No systematic bias was found between examinations on different days. CONCLUSIONS: The intrasession repeatability was high; therefore, the device’s ability to measure HOAs in a reliable way was excellent. Under intersession reproducibility conditions, dependable corneal primary spherical aberrations were provided. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Concepts: Optics, Measurement, Metrology, Psychometrics, Cornea, Pupil, Wavefront, Adaptive optics

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To establish a corneal correction equation for the Shammas post-hyperopic laser in situ keratomileusis (LASIK) (Shammas-PHL) formula and to evaluate its accuracy in cases with and without available pre-LASIK data.

Concepts: Laser, Eye, Cornea, Refractive surgery, Lens, LASIK, Intraocular lens, Dioptre

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PURPOSE: To assess clinical outcomes and subjective experience after bilateral implantation of a diffractive trifocal intraocular lens (IOL). SETTING: Midland Eye Institute, Solihull, United Kingdom. DESIGN: Cohort study. METHODS: Patients had bilateral implantation of Finevision trifocal IOLs. Uncorrected distance visual acuity, corrected distance visual acuity (CDVA), and manifest refraction were measured 2 months postoperatively. Defocus curves were assessed under photopic and mesopic conditions over a range of +1.50 to -4.00 diopters (D) in 0.50 D steps. Contrast sensitivity function was assessed under photopic conditions. Halometry was used to measure the angular size of monocular and binocular photopic scotomas arising from a glare source. Patient satisfaction with uncorrected near vision was assessed using the Near Activity Visual Questionnaire (NAVQ). RESULTS: The mean monocular CDVA was 0.08 logMAR ± 0.08 (SD) and the mean binocular CDVA, 0.06 ± 0.08 logMAR. Defocus curve testing showed an extended range of clear vision from +1.00 to -2.50 D defocus, with a significant difference in acuity between photopic conditions and mesopic conditions at -1.50 D defocus only. Photopic contrast sensitivity was significantly better binocularly than monocularly at all spatial frequencies. Halometry showed a glare scotoma of a mean size similar to that in previous studies of multifocal and accommodating IOLs; there were no subjective complaints of dysphotopsia. The mean NAVQ Rasch score for satisfaction with near vision was 15.9 ± 10.7 logits. CONCLUSIONS: The trifocal IOL implanted binocularly produced good distance visual acuity and near and intermediate visual function. Patients were very satisfied with their uncorrected near vision. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Concepts: Eye, Vision, Visual perception, Visual acuity, Lens, Intraocular lens, Binoculars

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To evaluate the reasons for the required increased radiant exposure for higher-repetition-rate excimer lasers and determine experimentally possible compensations to achieve equivalent ablation profiles maintaining the same single-pulse energies and radiant exposures for laser repetition rates ranging from 430 to 1000 Hz.

Concepts: Quantum mechanics, Light, Laser, Nuclear fusion, Excimer, LASIK, Excimer laser

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To identify risk factors for late in-the-bag intraocular lens (IOL) dislocation and estimate incidence of this condition over a 21-year period.

Concepts: Epidemiology, Lens, Intraocular lens

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To evaluate astigmatism induced by aspheric and toric intraocular lens (IOL) tilt using a ray-tracing model.

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To compare the effectiveness of intravitreal injection of triamcinolone acetonide-moxifloxacin (Tri-Moxi) to a standard eyedrop regimen in controlling postoperative inflammation, corneal edema, and the rate of high intraocular pressure (IOP) among cataract patients.

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To assess 5-year outcomes after implantation of 1 trabecular microbypass stent during cataract surgery in eyes with open-angle glaucoma (OAG) or ocular hypertension.