Accommodative Insufficiency, Ill-sustained Accommodation
Conditions
Keywords
Accommodation, Reading, Autorefraction
Brief summary
This project will develop clinically useful, objective measurements of accommodative insufficiency and fatigue using continuous autorefraction recordings. The development of these procedures will help vision care professionals diagnose and treat accommodative anomalies.
Detailed description
This project studies accommodative function, the ability to focus while doing near work. Visual discomfort symptoms, such as headaches, sore eyes, and blurred vision are commonly associated with prolonged reading or other near work. Researchers have long suspected accommodative dysfunction was involved but most clinical studies have failed to establish a relationship between weak accommodation and symptoms or reading impairments. Recent research, however, has found that clinical measure overestimate accommodative function and encourage the use of objective, autorefraction methods to measure and study accommodative weakness. This project will accomplish three goals. First, using autorefraction objective reliable procedures will be developed for measuring accommodative lag, the difference between the target location and where the eye is focused. Second, experiments will measure in real-time the impact of accommodative lag on reading fluency and visual discomfort systems. Third, studies will explore the role of the slow adaptive component in accommodative weakness. This work will lead to better methods for diagnosing and treating accommodative disorders.
Interventions
None listed
Sponsors
Southern California College of Optometry at Marshall B. Ketchum University
Western University of Health Sciences
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to 30 Years
Healthy volunteers
Yes
Inclusion criteria
* older adolescent and young adult * skilled readers who attend school * are skilled readers * have heavy reading demands
Exclusion criteria
* Age \> 30. * Abnormal vergence system. * Dry-eye. * Uncorrected visual defects or significant ocular pathology. * Learning disability or low IQ * Medical conditions that might cause uncomfortable visual symptoms (e.g., migraine headaches, epilepsy, head trauma); sensory defects (e.g., deafness), or neurological conditions (e.g., stuttering) that could impair reading development or oral reading fluency. * Somatosensory amplification. * Systemic illness or medication associated with accommodative dysfunction.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Accommodation Lag 5D | 3 week period | Lag will be measured at different viewing distances and durations using autorefraction. Accommodation error refers to the difference between the distance where the target is located and where the eyes focus. Lag refers error that is under focussed; lead is error that is over focussed. This distance is measured in diopters, or 1/meter. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Conlon Symptom Survey | 3 weeks | Measures visual discomfort symptoms while doing near work. 23 item survey using a 4-point rating scale (never, occasionally, often, almost always). Total raw score reported on a range from 0 to 69 with higher scores indicating more frequent symptoms. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Discomfort Symptoms level of discomfort symptoms while performing near work | 83 |
| Total | 83 |
Baseline characteristics
| Characteristic | Discomfort Symptoms |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 83 Participants |
| Conlon Symptom Score | 24.4 units on a scale STANDARD_DEVIATION 9.4 |
| Region of Enrollment United States | 83 participants |
| Sex: Female, Male Female | 57 Participants |
| Sex: Female, Male Male | 26 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | — / — |
| other Total, other adverse events | 0 / 83 |
| serious Total, serious adverse events | 0 / 83 |
Outcome results
Primary
Accommodation Lag 5D
Lag will be measured at different viewing distances and durations using autorefraction. Accommodation error refers to the difference between the distance where the target is located and where the eyes focus. Lag refers error that is under focussed; lead is error that is over focussed. This distance is measured in diopters, or 1/meter.
Time frame: 3 week period
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Discomfort Symptoms | Accommodation Lag 5D | 0.9 diopters | Standard Deviation 0.6 |
Secondary
Conlon Symptom Survey
Measures visual discomfort symptoms while doing near work. 23 item survey using a 4-point rating scale (never, occasionally, often, almost always). Total raw score reported on a range from 0 to 69 with higher scores indicating more frequent symptoms.
Time frame: 3 weeks
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Discomfort Symptoms | Conlon Symptom Survey | 18.6 units on a scale | Standard Deviation 12.7 |