Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 5 uppsatser.

Diss. (sammanfattning) Umeå : Umeå universitet, 2010. / Härtill 4 uppsatser. Även tryckt utgåva.

Aberrations affect image quality of the eye away from the line of sight as well as along it. High amounts of lower order aberrations are found in the peripheral visual field and higher order aberrations change away from the centre of the visual field. Peripheral resolution is poorer than that in central vision, but peripheral vision is important for movement and detection tasks (for example driving) which are adversely affected by poor peripheral image quality. Any physiological process or intervention that affects axial image quality will affect peripheral image quality as well. The aim of this study was to investigate the effects of accommodation, myopia, age, and refractive interventions of orthokeratology, laser in situ keratomileusis and intraocular lens implantation on the peripheral aberrations of the eye. This is the first systematic investigation of peripheral aberrations in a variety of subject groups. Peripheral aberrations can be measured either by rotating a measuring instrument relative to the eye or rotating the eye relative to the instrument. I used the latter as it is much easier to do. To rule out effects of eye rotation on peripheral aberrations, I investigated the effects of eye rotation on axial and peripheral cycloplegic refraction using an open field autorefractor. For axial refraction, the subjects fixated at a target straight ahead, while their heads were rotated by ±30º with a compensatory eye rotation to view the target. For peripheral refraction, the subjects rotated their eyes to fixate on targets out to ±34° along the horizontal visual field, followed by measurements in which they rotated their heads such that the eyes stayed in the primary position relative to the head while fixating at the peripheral targets. Oblique viewing did not affect axial or peripheral refraction. Therefore it is not critical, within the range of viewing angles studied, if axial and peripheral refractions are measured with rotation of the eye relative to the instrument or rotation of the instrument relative to the eye. Peripheral aberrations were measured using a commercial Hartmann-Shack aberrometer. A number of hardware and software changes were made. The 1.4 mm range limiting aperture was replaced by a larger aperture (2.5 mm) to ensure all the light from peripheral parts of the pupil reached the instrument detector even when aberrations were high such as those occur in peripheral vision. The power of the super luminescent diode source was increased to improve detection of spots passing through the peripheral pupil. A beam splitter was placed between the subjects and the aberrometer, through which they viewed an array of targets on a wall or projected on a screen in a 6 row x 7 column matrix of points covering a visual field of 42 x 32. In peripheral vision, the pupil of the eye appears elliptical rather than circular; data were analysed off-line using custom software to determine peripheral aberrations. All analyses in the study were conducted for 5.0 mm pupils. Influence of accommodation on peripheral aberrations was investigated in young emmetropic subjects by presenting fixation targets at 25 cm and 3 m (4.0 D and 0.3 D accommodative demands, respectively). Increase in accommodation did not affect the patterns of any aberrations across the field, but there was overall negative shift in spherical aberration across the visual field of 0.10 ± 0.01m. Subsequent studies were conducted with the targets at a 1.2 m distance. Young emmetropes, young myopes and older emmetropes exhibited similar patterns of astigmatism and coma across the visual field. However, the rate of change of coma across the field was higher in young myopes than young emmetropes and was highest in older emmetropes amongst the three groups. Spherical aberration showed an overall decrease in myopes and increase in older emmetropes across the field, as compared to young emmetropes. Orthokeratology, spherical IOL implantation and LASIK altered peripheral higher order aberrations considerably, especially spherical aberration. Spherical IOL implantation resulted in an overall increase in spherical aberration across the field. Orthokeratology and LASIK reversed the direction of change in coma across the field. Orthokeratology corrected peripheral relative hypermetropia through correcting myopia in the central visual field. Theoretical ray tracing demonstrated that changes in aberrations due to orthokeratology and LASIK can be explained by the induced changes in radius of curvature and asphericity of the cornea. This investigation has shown that peripheral aberrations can be measured with reasonable accuracy with eye rotation relative to the instrument. Peripheral aberrations are affected by accommodation, myopia, age, orthokeratology, spherical intraocular lens implantation and laser in situ keratomileusis. These factors affect the magnitudes and patterns of most aberrations considerably (especially coma and spherical aberration) across the studied visual field. The changes in aberrations across the field may influence peripheral detection and motion perception. However, further research is required to investigate how the changes in aberrations influence peripheral detection and motion perception and consequently peripheral vision task performance.

Introdução: A partir de relatos casos de opacifiação da lente intraocular acrílica hidrofílica Ioflex (Mediphacos, Belo Horizonte, Brasil), muitas vezes utilizada em mutirões de catarata para pessoas carentes, avaliamos a frequência das complicações oculares relacionadas com o implante desta lente quatro anos após a cirurgia, bem como seus efeitos a longo prazo na eficiência da cirurgia de catarata. Métodos: Foi selecionada amostra aleatória com 102 indivíduos submetidos à cirurgia de catarata com implante da lente intraocular Ioflex, em campanha comunitária no interior de Pernambuco, Brasil, quatro anos após a cirurgia. Um total de 31 pacientes não foi localizado e treze (18,3%) não compareceram para o exame. Assim, 58 pacientes (87 olhos) foram examinados. Para o cálculo da frequência da opacificação da cápsula posterior e para a avaliação da eficiência da cirurgia da catarata, foi selecionado apenas um olho de cada paciente. Os sujeitos foram submetidos a exame oftalmológico completo. Pacientes com redução da acuidade visual decorrentes das complicações pós-operatórias foram encaminhados para tratamento. O custo desses eventuais tratamentos foi estimado para análise da eficiência da cirurgia de catarata com a lente Ioflex. Para avaliação dos índices de opacificação da cápsula posterior as variáveis foram expressas por média e desvio padrão. Foi usado o teste t de Student\'s para análise de diferenças entre amostras independentes e pareadas. Resultados: Seis olhos (7%) apresentaram opacificação da lente intraocular. Nenhuma doença ou fator ambiental foi relacionado à opacificação da lente. A opacificação da cápsula posterior foi detectada em 39 (67%) olhos, sendo 24 (41,3%) olhos submetidos ao tratamento com laser para recuperação da acuidade visual. O custo total do tratamento das complicações pós-operatórias representou 6,3% do orçamento cirúrgico inicial. O custo adicional foi de $9,03 dólares por paciente para manter a boa acuidade visual. Conclusão: A lente intraocular acrílica hidrofílica Ioflex apresentou elevada frequência de complicações pós-operatórias tardias relacionadas à própria lente, reduzindo, a longo prazo, a eficácia e eficiência da cirurgia de catarata / Introduction: Based on reports of Ioflex hydrophilic acrylic intraocular lens opacification (Mediphacos, Belo Horizonte, Brazil), used in cataract surgeries for underserved communities, we evaluated the ocular complications related to the intraocular lens implant, four years after surgery, as well as its effects on the visual efficiency of long-term cataract surgery. Methods: A random sample of 102 patients that underwent cataract surgery and Ioflex intraocular lens implantation, in a community campaign in the rural area from Pernambuco, Brazil, four years after surgery. A total of 31 patients could not be located and 13 (18.3%) were not present for examination. Thus, 58 patients (87 eyes) were available for examination. In order to calculate the frequency of posterior capsule opacification and to evaluate the efficiency of cataract surgery, only one eye was selected from each patient. The subjects underwent a complete ophthalmological examination. Patients with reduced visual acuity due to postoperative complications were referred for treatment. The costs of these treatments were estimated for the analysis of the efficiency of the cataract surgery with the Ioflex lens in the long term period. For the evaluation of posterior capsule opacification rates the variables were expressed by means and standard deviation. The Student\'s t test was used for analysis the differences between independent and paired samples. Results: Six eyes (7.0%) had intraocular lens opacification. No disease or environmental factor could be related to intraocular lens opacification. Posterior capsule opacification was detected in 39 (67%) eyes, and 24 (41.3%) eyes were submitted to laser treatment for visual acuity recovered. The total cost of postoperative complications treatment represented 6.3% from the initial budget of the whole patients group evaluated. The additional costs to maintain a good visual outcome was USD $9.03 per patient with Ioflex lens implantation. Conclusion: The Ioflex hydrophilic acrylic intraocular lens had high rates of postoperative complications related to the intraocular lens itself, decreasing effectiveness efficiency in long-term cataract surgery

Introdução: A partir de relatos casos de opacifiação da lente intraocular acrílica hidrofílica Ioflex (Mediphacos, Belo Horizonte, Brasil), muitas vezes utilizada em mutirões de catarata para pessoas carentes, avaliamos a frequência das complicações oculares relacionadas com o implante desta lente quatro anos após a cirurgia, bem como seus efeitos a longo prazo na eficiência da cirurgia de catarata. Métodos: Foi selecionada amostra aleatória com 102 indivíduos submetidos à cirurgia de catarata com implante da lente intraocular Ioflex, em campanha comunitária no interior de Pernambuco, Brasil, quatro anos após a cirurgia. Um total de 31 pacientes não foi localizado e treze (18,3%) não compareceram para o exame. Assim, 58 pacientes (87 olhos) foram examinados. Para o cálculo da frequência da opacificação da cápsula posterior e para a avaliação da eficiência da cirurgia da catarata, foi selecionado apenas um olho de cada paciente. Os sujeitos foram submetidos a exame oftalmológico completo. Pacientes com redução da acuidade visual decorrentes das complicações pós-operatórias foram encaminhados para tratamento. O custo desses eventuais tratamentos foi estimado para análise da eficiência da cirurgia de catarata com a lente Ioflex. Para avaliação dos índices de opacificação da cápsula posterior as variáveis foram expressas por média e desvio padrão. Foi usado o teste t de Student\'s para análise de diferenças entre amostras independentes e pareadas. Resultados: Seis olhos (7%) apresentaram opacificação da lente intraocular. Nenhuma doença ou fator ambiental foi relacionado à opacificação da lente. A opacificação da cápsula posterior foi detectada em 39 (67%) olhos, sendo 24 (41,3%) olhos submetidos ao tratamento com laser para recuperação da acuidade visual. O custo total do tratamento das complicações pós-operatórias representou 6,3% do orçamento cirúrgico inicial. O custo adicional foi de $9,03 dólares por paciente para manter a boa acuidade visual. Conclusão: A lente intraocular acrílica hidrofílica Ioflex apresentou elevada frequência de complicações pós-operatórias tardias relacionadas à própria lente, reduzindo, a longo prazo, a eficácia e eficiência da cirurgia de catarata / Introduction: Based on reports of Ioflex hydrophilic acrylic intraocular lens opacification (Mediphacos, Belo Horizonte, Brazil), used in cataract surgeries for underserved communities, we evaluated the ocular complications related to the intraocular lens implant, four years after surgery, as well as its effects on the visual efficiency of long-term cataract surgery. Methods: A random sample of 102 patients that underwent cataract surgery and Ioflex intraocular lens implantation, in a community campaign in the rural area from Pernambuco, Brazil, four years after surgery. A total of 31 patients could not be located and 13 (18.3%) were not present for examination. Thus, 58 patients (87 eyes) were available for examination. In order to calculate the frequency of posterior capsule opacification and to evaluate the efficiency of cataract surgery, only one eye was selected from each patient. The subjects underwent a complete ophthalmological examination. Patients with reduced visual acuity due to postoperative complications were referred for treatment. The costs of these treatments were estimated for the analysis of the efficiency of the cataract surgery with the Ioflex lens in the long term period. For the evaluation of posterior capsule opacification rates the variables were expressed by means and standard deviation. The Student\'s t test was used for analysis the differences between independent and paired samples. Results: Six eyes (7.0%) had intraocular lens opacification. No disease or environmental factor could be related to intraocular lens opacification. Posterior capsule opacification was detected in 39 (67%) eyes, and 24 (41.3%) eyes were submitted to laser treatment for visual acuity recovered. The total cost of postoperative complications treatment represented 6.3% from the initial budget of the whole patients group evaluated. The additional costs to maintain a good visual outcome was USD $9.03 per patient with Ioflex lens implantation. Conclusion: The Ioflex hydrophilic acrylic intraocular lens had high rates of postoperative complications related to the intraocular lens itself, decreasing effectiveness efficiency in long-term cataract surgery

No / To determine whether Hartmann-Shack wavefront sensing detects differences in optical performance in vivo between poly(methyl methacrylate) (PMMA) and foldable acrylic intraocular lenses (IOLs) and between clear corneal and scleral tunnel incisions and whether optical differences are manifested as differences in visual performance. SETTING: Department of Optometry, University of Bradford, West Yorkshire, United Kingdom. METHODS: This study comprised 74 subjects; 17 were phakic with no ocular pathology, 20 had implantation of a Pharmacia 722C PMMA IOL through a scleral tunnel, 21 had implantation of an Alcon AcrySof IOL through a scleral tunnel, and 16 had implantation of an AcrySof IOL through a corneal incision. Visual acuity and contrast sensitivity testing, ocular optical quality measurement using Hartmann-Shack wavefront sensing, and corneal surface measurement with a videokeratoscope were performed in all cases. RESULTS: There were significant differences between groups in the total root-mean-square (RMS) wavefront aberration over a 6.0 mm pupil (F=3.91; degrees of freedom=3,70; P<.05) mediated at the 4th-order RMS, specifically spherical and tetrafoil aberrations. The PMMA-scleral group had the least aberrations and the AcrySof-corneal group the most. For a 3.5 mm diameter pupil, the total higher-order RMS wavefront aberration was not significantly different between the groups (P>.05). There were no differences between groups in corneal shape, visual acuity, or contrast sensitivity. CONCLUSIONS: Implantation of the spherical PMMA IOL led to a slight reduction in total wavefront aberration compared to phakic eyes. AcrySof IOLs induced more aberrations, especially spherical aberration. Corneal-based incisions for IOL implantation compounded this increase. Studies of the optical performance of IOLs in vivo should use wavefront sensing as the main outcome measure rather than visual measures, which are readily confounded by multiple factors.