Dark Focus of Accommodation
Conditions
Keywords
accommodation, dark focus, night myopia
Brief summary
Shifts in accommodation at decreasing luminance levels are considered as principle cause for night myopia. Previous studies with laser optometers quantified the dark focus of accommodation up to 3 D. In addition to the measurement of dark focus, the aim of this study was to investigate the influence of an imaginary target at finite distances on the state of accommodation at scotopic luminance.
Detailed description
Accommodation was measured by using an open-field autorefractor (WAM 5500, GRAND SEIKO). Full corrected right eyes of 39 subjects aged from 18 to 40 years were investigated in this randomized, cross-sectional study. Accommodation measurements in photopic luminance were taken for 6 m of empty field and for optotype fixation at 2 m, 1 m and 0.5 m. At scotopic luminance, dark focus of accommodation was examined directly after darkening and after 10 min of dark adaptation. After adaptation, subjects had to visualize imaginary targets in the four distances while accommodation was measured.
Interventions
DIAGNOSTIC_TESTAccommodation Measurement
Accommodation was measured for different distances and light conditions.
Sponsors
University of Applied Sciences Jena
Study design
Allocation
RANDOMIZED
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Masking description
Sequence of tests was randomized. It is no multi-arm study.
Eligibility
Sex/Gender
ALL
Age
22 Years to 39 Years
Healthy volunteers
Yes
Inclusion criteria
* age 18 - 44 * visual acuity at least 0.8 (5/6)
Exclusion criteria
* medication with an impact on the visual system * visual disease or disease with an impact on the visual system * pregnancy or other hormonal variances * drug usage * overfatigue at the period of investigation * mental handicap
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Shift of accommodation in scotopic luminance (Dark focus) | Baseline only | Accommodative shift in scotopic luminance compared to photopic luminance for empty field (dark focus of accommodation) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Difference of accommodation for 2 m target | Baseline only | Accommodative shift in scotopic luminance compared to photopic luminance for the fixation of a target in 2 m |
| Difference of accommodation for 1 m target | Baseline only | Accommodative shift in scotopic luminance compared to photopic luminance for the fixation of a target in 1 m |
| Difference of accommodation for 0.5 m target | Baseline only | Accommodative shift in scotopic luminance compared to photopic luminance for the fixation of a target in 0.5 m |
Countries
Germany
Outcome results
None listed