by Maksudul Islam. / Publication date from spine. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 58-65). / Questionaire also in Chinese. / Chapter CHAPTER1 --- ABSTRACT --- p.1 / Chapter CHAPTER2 --- INTRODUCTION --- p.3 / Chapter CHAPTER3 --- OBJECTIVES --- p.7 / Chapter CHAPTER4 --- LITERATURE REVIEW --- p.8 / Chapter 4.1.1 --- BACKGROUND --- p.8 / Chapter 4.1.2 --- GENETIC AND ENVIRONMENTAL STUDY --- p.9 / Chapter 4.1.3 --- EPIDEMIOLOGY OF MYOPIA --- p.14 / Chapter 4.1.4 --- RELATIONSHIP BETWEEN MYOPIA & OPTICAL COMPONENTS --- p.18 / Chapter 4.1.5 --- AXIAL LENGTH --- p.19 / Chapter 4.1.6 --- VITREOUS LENGTH --- p.20 / Chapter 4.1.7 --- CHANGES OF REFRACTION IN SCHOOL CHILDREN --- p.21 / Chapter 4.1.8 --- DEVELOPMENT OF MYOPIA --- p.23 / Chapter 4.1.9 --- EMMETROPIZATION --- p.26 / Chapter 4.1.10 --- SEX --- p.27 / Chapter 4.1.11 --- FACTORS --- p.29 / Chapter CHAPTER5 --- METHODS --- p.34 / SUBJECTS --- p.34 / PROCEDURE --- p.35 / Chapter CHAPTER6 --- RESULTS --- p.37 / Chapter 6.1.1 --- THE DISTRIBUTION OF REFRACTION --- p.37 / Chapter 6.1.2 --- THE RELATION BETWEEN AGE WITH REFRACTION AND OPTICAL COMPONENTS --- p.38 / Chapter 6.1.3 --- RELATION BETWEEN SEX AND REFRACTION --- p.39 / Chapter 6.1.4 --- RELATION BETWEEN REFRACTION AND OPTICAL COMPONENTS --- p.39 / Chapter 6.1.5 --- RELATION BETWEEN REFRACTION AND VISUAL TASK --- p.40 / Chapter 6.1.6 --- RELATION BETWEEN OCULAR COMPONENTS AND VISUAL TASK --- p.42 / Chapter 6.1.7 --- RELATION BETWEEN OCULAR COMPONENTS AND REFRACTION TO PARENTAL MYOPIA AND EDUCATION --- p.44 / Chapter CHAPTER7 --- DISCUSSION --- p.47 / Chapter CHAPTER8 --- REFERENCES --- p.58 / TABLES --- p.66 / FIGURES --- p.86 / APPENDIX I-II QUESTIONNAIRE IN CHINESE --- p.100 / APPENDIX III-IV QUESTIONNAIRE IN ENGLISH TRANSLATION --- p.110

Thesis (M.S.P.H.)--University of Michigan, 1942.

Lo Peng-iok. / Includes questionnaire in Chinese. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 51-58). / List of tables --- p.V / List of figures --- p.VIII / List of abbreviations --- p.IX / Acknowledgments --- p.X / Abstract --- p.XI / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Literature review --- p.3 / Chapter 2.1 --- The history of myopia --- p.3 / Chapter 2.2 --- The epidemiological study of myopia --- p.4 / Chapter 2.3 --- The relationship between myopia and optical components --- p.7 / Chapter 2.4 --- The classification of myopia --- p.9 / Chapter 2.5 --- Myopia and blindness --- p.11 / Chapter Chapter 3 --- Material and methods --- p.13 / Chapter 3.1 --- Material --- p.13 / Chapter 3.2 --- Methods --- p.14 / Chapter 3.2.1 --- Questionnaire --- p.14 / Chapter 3.2.2 --- Eye examination --- p.15 / Chapter I). --- Autorefraction --- p.15 / Chapter II). --- Keratometry --- p.16 / Chapter III). --- Opthalmoscopy --- p.16 / Chapter IV). --- A-scan Biometry --- p.16 / Chapter V). --- Tonometry --- p.17 / Chapter 3.2.3 --- Data analysis --- p.17 / Chapter Chapter 4 --- Results --- p.19 / Chapter 4.1 --- The distribution of refraction --- p.19 / Chapter 4.1.1 --- The distribution of refraction among 2150 eyes of 1075 students --- p.19 / Chapter 4.1.2 --- The distribution of refraction (right eye) by sex and age --- p.20 / Chapter 4.1.3 --- The distribution of refraction (right eye) by faculty --- p.21 / Chapter 4.1.4 --- The astigmatism among 1075 freshmen --- p.22 / Chapter 4.1.5 --- The anisometropia and isometropia among 1075 freshmen --- p.22 / Chapter 4.2 --- Relationship between the ocular refraction and its optical components --- p.23 / Chapter 4.2.1 --- The results of keratometry and A-scan ultrasound measurements --- p.24 / Chapter 4.2.2 --- The distribution of the ocular components --- p.24 / Chapter 4.2.3 --- The association between the refraction and optical components --- p.25 / Chapter 4.2.4 --- The association between various optical components --- p.27 / Chapter 4.2.5 --- The association between the myopia and optical components --- p.28 / Chapter 4.3 --- "Relationship between refraction and corrected visual acuity, fundus changes and intraocular pressure" --- p.30 / Chapter 4.3.1 --- The association between refraction and corrected visual acuity --- p.30 / Chapter 4.3.2 --- The association between refraction and fundus changes --- p.31 / Chapter 4.3.3 --- The association between refraction and intraocular pressure --- p.32 / Chapter 4.4 --- Relationship between myopia and environmental factors --- p.32 / Chapter 4.4.1 --- Present myopia in relation to age at onset of myopia --- p.33 / Chapter 4.4.2 --- The Influence of nearwork on myopia in freshmen --- p.34 / Chapter 4.4.3 --- The Influence of sports on myopia in freshmen --- p.35 / Chapter 4.4.4 --- The influence of achievement on myopia --- p.36 / Chapter 4.4.5 --- "The influence of time spent in front of TV set and computer, sleeping habit on myopia" --- p.36 / Chapter 4.5 --- The relationship between myopia and family background --- p.37 / Chapter 4.5.1 --- The relation between myopia and parents' refractive status --- p.37 / Chapter 4.5.2 --- The relation between myopia and parents' education level --- p.38 / Chapter 4.5.3 --- The relation between myopia and family income --- p.38 / Chapter Chapter 5 --- Discussion --- p.40 / Chapter 5.1 --- The high prevalence and high degree of myopia in Hong Kong Chinese students --- p.40 / Chapter 5.2 --- The relationship between refraction and its optical components in Hong Kong Chinese students --- p.43 / Chapter 5.3 --- The relationship between myopia and age at onset of myopia in Hong Kong Chinese students --- p.46 / Chapter 5.4 --- The relationship between myopia and environmental factors in Hong Kong Chinese students --- p.48 / References --- p.51 / Tables --- p.59 / Figures --- p.93 / Chapter Appendix I --- Questionnaire --- p.106 / Chapter Appendix II --- An English translation of the questionnaire --- p.110

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Oct. 31, 2007). Includes bibliographical references (p. 152-161).

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

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.

Thesis (Ph. D.)--University of Oklahoma. / Bibliography: leaves 164-207.

<p>Stopa prematuriteta konstantno raste, a sve vi&scaron;e prevremeno rođenih beba koje prežive neonatalni i perinatalni period zahteva adekvatno sistemsko i oftalmolo&scaron;ko praćenje i tretman. Prematuritet sam po sebi, predstavlja rizik za razvoj vida. Taj rizik dodatno povećava prisustvo prematurne retinopatije i refraktivnih mana. Skrining i tretman promena na retini u sklopu prematuriteta, kao i optička korekcija refraktivnih mana obezbeđuju uslove za razvoj vida. Cilj ovog istraživanja je bio utvrditi promene biometrijskih karakteristika oka prematurusa, sa i bez prematurne retinopatije, tokom &scaron;estogodi&scaron;njeg praćenja, utvrditi refraktivni status ove dve grupe dece sa &scaron;est godina, te povezati promene biometrijskih karakteristika oka sa refrakcijom. U ispitivanje je uključeno 192 prevremeno rođena deteta (384 oka). Vr&scaron;ena su tri pregleda, u uzrastu od 3 meseca, 12 meseci i 6 godina starosti. Nakon prvog pregleda ispitivani uzorak je, u zavisnosti od nalaza na očnom dnu, podeljen na bebe sa prematurnom retinopatijom i bebe bez ovog oboljenja, a kako bi se uporedile proučavane karakteristike. U sva tri navedena uzrasta je pregledano očno dno i merene su tri glavne biometrijske karakteristike koje utiču na refraktivni status: aksijalna dužina oka, dubina prednje očne komore i debljina očnog sočiva. Sa &scaron;est godina je određena refrakcija, uključujući zakrivljenost rožnjače odnosno kornealni astigmatizam, vidna o&scaron;trina bez korekcije refraktivne mane, a zatim i nakon korekcije. Ostali neophodni podaci su dobijeni iz medicinske dokumentacije. Pokazano je da prematurna retinopatija utiče na refraktivni status i vidni ishod sa &scaron;est godina, pre svega uticajem na zakrivljenost rožnjače, aksijalnu dužinu oka i dubinu prednje očne komore, dok su promene debljine očnog sočiva bez posebnog značaja. Vidne o&scaron;trine oba oka u pred&scaron;kolskom uzrastu prevremeno rođene dece sa prematurnom retinopatijom su statistički značajno manje kada se uporede sa vidnim o&scaron;trinama prevremeno rođene dece bez retinopatije, ali razlika u ovim dvema vrednostima gubi statističku značajnost nakon optičke korekcije. Učestalost astigmatizma u prematurnoj populaciji sa 6 godina je visoka, a od onih koji imaju astigmatizam u tom uzrastu, vi&scaron;e od dve trećine je imalo prematurnu retinopatiju. Ukupna učestalost miopije, hipermetropije i emetropije u prematurnoj populaciji sa 6 godina je 18,9%, 54,7% i 13,2%, a preostalih 13,2% su anizometropi. U vi&scaron;e od trećine dece, sa prematurnom retinopatijom u najranijem uzrastu, sa &scaron;est godina postoji gubitak vidne sposobnosti, koji je najče&scaron;će blag, no može biti i potpun.</p> / <p>The number of babies born prematurely is constantly growing, so more and more of them need appropriate systemic and ophthalmologic monitoring and treatament. Prematurity itself, represents a risk for the development of vision. This risk further reinforces the presence of retinopathy of prematurity and refractive errors. Screening and treatment of retinopathy, as well as optical correction of refractive errors provide adequate conditions for the development of vision. The aim of this study was to determine changes of biometric features of eyes of the prematurely born infants, with and without retinopathy of prematurity, during the six-year follow-up. We also want to determine the refractive status of these two groups of children in the six year, and to link changes of biometric features with their eye refraction. The study included 192 prematurely born children (384 eyes). The examinations were performed at 3 months, 12 months and 6 years and they included fundus examination and measurements of the ocular axial length, anterior chamber depth and lens thickness. After dividing the subjects into two groups, based on the results of the fundus examination at 3 months, the results of the children with and without retinopathy were compared. At the age of six we also determine the refraction of eyes, including the curvature of the cornea and corneal astigmatism, visual acuity without correction of refractive error, and then after it. Other necessary data were obtained from medical documentation. It is shown that retinopathy of prematurity affects the refractive status and visual outcome at sixth year, primarily by the changes of curvature of the cornea, the axial length of the eye and the depth of the anterior chamber, while the change in the lens thickness has no significance. Visual acuity in both eyes in the preschool age preterm born children with retinopathy of prematurity are significantly less, when compared to visual acuity in preterm infants without retinopathy, but the difference in these two values lost statistical significance after optical correction. The rate of astigmatism in preterm population of six years is high, and of those who have astigmatism in this age group, more than two-thirds had retinopathy of prematurity. The overall incidence of myopia, hypermetropia and emetropia in the prematurely born, six years old children is 18.9%, 54.7% and 13.2%, and the remaining 13.2% have anisometropia. In more than a third of children with retinopathy of prematurity at an early age, with six years, there has been loss of visual acuity, which is usually mild, but it can be complete.</p>

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.

no / PURPOSE: To estimate refractive indices used by the Lenstar biometer to translate measured optical path lengths into geometrical path lengths within the eye. METHODS: Axial lengths of model eyes were determined using the IOLMaster and Lenstar biometers; comparing those lengths gave an overall eye refractive index estimate for the Lenstar. Using the Lenstar Graphical User Interface, we noticed that boundaries between media could be manipulated and opposite changes in optical path lengths on either side of the boundary could be introduced. Those ratios were combined with the overall eye refractive index to estimate separate refractive indices. Furthermore, Haag-Streit provided us with a template to obtain 'air thicknesses' to compare with geometrical distances. RESULTS: The axial length estimates obtained using the IOLMaster and the Lenstar agreed to within 0.01 mm. Estimates of group refractive indices used in the Lenstar were 1.340, 1.341, 1.415, and 1.354 for cornea, aqueous, lens, and overall eye, respectively. Those refractive indices did not match those of schematic eyes, but were close in the cases of aqueous and lens. Linear equations relating air thicknesses to geometrical thicknesses were consistent with our findings. CONCLUSION: The Lenstar uses different refractive indices for different ocular media. Some of the refractive indices, such as that for the cornea, are not physiological; therefore, it is likely that the calibrations in the instrument correspond to instrument-specific corrections and are not the real optical path lengths.