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1.
Ophthalmic Physiol Opt ; 16(4): 342-7, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8796204

RESUMO

Based on the dual-interactive feedback model, dark focus and dark vergence designate a point on a line describing the response AC/A ratio. In order to verify the relationship between dark focus and dark vergence, we predicted the dark vergence from the measured dark focus when the measurements were based on the response-based calculated and gradient AC/A ratios. For 10 subjects, the correlations between predicted and measured dark vergence values were high. The prediction was better when using the gradient AC/A ratio.


Assuntos
Acomodação Ocular/fisiologia , Convergência Ocular/fisiologia , Escuridão , Adolescente , Adulto , Retroalimentação/fisiologia , Humanos , Matemática , Modelos Biológicos
2.
Optom Vis Sci ; 73(4): 231-4, 1996 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8728489

RESUMO

In this case report, we present 3 years of longitudinal, refractive component data for a young adult who became myopic and progressed in myopia (late-onset myopia, LOM) during that period. We found a high correlation between refractive error and axial length (AL). The axial elongation was a consequence of the change in the vitreous chamber depth (VCD). Furthermore, the change in AL and VCD corresponded quantitatively to the change in refractive error. Corneal curvature change was not correlated with refractive error change. These findings support the suggestion that VCD is the refractive component that changes in LOM development.


Assuntos
Miopia/etiologia , Corpo Vítreo/fisiologia , Adulto , Progressão da Doença , Olho/diagnóstico por imagem , Feminino , Humanos , Estudos Longitudinais , Miopia/diagnóstico por imagem , Miopia/fisiopatologia , Estudos Prospectivos , Refração Ocular , Análise de Regressão , Ultrassonografia
3.
Optom Vis Sci ; 67(11): 833-9, 1990 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-2250892

RESUMO

A retrospective survey of 5000 active aircrew records was performed at 12 United States Air Force (USAF) bases to obtain information about the prevalence of spectacle wear and refractive error. The data revealed that 27.4% of pilots and 51.5% of navigators/weapons systems operators (Nav/WSO) required spectacles when flying. Of the spectacle-wearing pilots, 12.4% required bifocals. Myopia was the predominant refractive error and a relatively large percentage of aircrew members had astigmatism of 0.75 D or more, e.g., 33.1% of pilots. At the time of entry into the USAF, refractive error data were clustered around emmetropia with a definite skew toward hyperopia.


Assuntos
Óculos , Militares , Erros de Refração/epidemiologia , Adulto , Fatores Etários , Astigmatismo/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Miopia/terapia , Prevalência , Erros de Refração/terapia , Estudos Retrospectivos , Estados Unidos , Acuidade Visual
4.
Aviat Space Environ Med ; 61(10): 906-12, 1990 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2241731

RESUMO

This study was designed to determine how well rigid gas-permeable contact lenses maintain position on the cornea under high G forces, and the effect on visual acuity. One hyperopic and five myopic subjects were fitted with lenses made from Pasifocon C material (specific gravity = 1.07). Two lens diameters (8.8-9.4 mm and 9.6-10.0 mm) were compared upon the myopic subjects for centering on the cornea. Visual acuity was measured at + 1 Gz (baseline), +3 Gz, +4 Gz, +6 Gz, and +8 Gz in the straight-ahead, lateral, and up-gaze positions from three acuity charts mounted in the gondola. All lenses, as estimated from the videotape, decentered down the z axis 2-3 mm at high + Gz. Visual acuity was reduced at the higher +Gz levels to similar measurements in most subjects for both the contact lens and spectacle control rides. No lens displaced from the cornea or dislodged from the eye during any of the 25 centrifuge runs.


Assuntos
Medicina Aeroespacial , Lentes de Contato , Gravitação , Humanos , Hiperopia/reabilitação , Miopia/reabilitação , Gravidade Específica , Gravação de Videoteipe , Acuidade Visual
6.
Aviat Space Environ Med ; 54(7): 622-7, 1983 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-6882329

RESUMO

A field survey was conducted to determine the percentage of U.S. Air Force pilots and navigators required to wear corrective lenses. A random sample survey stratified by major air commands (MAJCOMS) was designed to retrieve the data. Data requested included initial (entry) visual acuity and refractive error, and current visual acuity and prescription if glasses were required. Of 2,383 forms sent, 2,183 were returned completed. Analysis indicated that almost 20% of pilots and 50% of navigators are required to wear corrective lenses while flying. The percentages are rather consistent among MAJCOMS. Aircrew members who enter undergraduate pilot training with minus or plano refractive values are much more susceptible to develop myopia during their flying careers than those with plus refractive values.


Assuntos
Óculos , Erros de Refração/epidemiologia , Acuidade Visual , Adulto , Medicina Aeroespacial , Fatores Etários , Lentes de Contato , Humanos , Hiperopia/epidemiologia , Medicina Militar , Miopia/epidemiologia
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