Application and Clinical Evaluation of Longitudinal Chromatic Aberration Technique in Ophthalmology

Beijing Tongren Hospital21 enrolled

Overview

Our study aims to delve into the effects of shifting the focal point of blue light from video or text displayed on a terminal screen forward on the axial length of the eye, ocular blood flow, visual fatigue, and visual function, that is, its relationship with Video Display Terminal (VDT) syndrome and myopia. By examining the decoding ability of the adult subjects' retina to the clarity of the signal, we will attempt to develop a novel, non-invasive strategy to curb the elongation of the eyeball associated with myopia. Concurrently, we will also focus on the pathophysiological mechanisms underlying VDT syndrome and explore its potential link to the progression of myopia, providing new scientific evidence for the prevention and treatment of this ocular condition. This research is expected to provide robust support for addressing the global issue of myopia and the health challenges posed by VDT syndrome. Ultimately, by integrating global eye health issues with the challenges brought about by VDT syndrome, we will propose intervention and prevention strategies, offering new insights for the advancement of ophthalmology and public health sectors, thereby promoting visual acuity and ocular health for the population.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

SINGLE

Enrollment

Conditions

Longitudinal Chromatic Aberration Blue Light Defocus Manipulation

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: 1. Adult population, regardless of gender 2. Refractive error is less than or equal to -2.5D and both eyes achieve corrected visual acuity of 0.8 or higher. 3. Normal intraocular pressure with no organic pathology. 4. No apparent symptoms of dry eye. 5. Willing to cooperate to complete all the tests. 6. Voluntarily signing the informed consent form. Exclusion Criteria: 1. Individuals with strabismus and amblyopia exist. 2. Suffering from congenital eye conditions such as congenital cataracts or congenital retinal diseases. 3. Those who have undergone intraocular surgery (such as cataract removal, intraocular lens implantation, etc.). 4. Individuals with refractive media opacity (such as corneal lesions, lens opacity, etc.). 5. Abnormal intraocular pressure (IOP) (IOP \< 10 mmHg or IOP \> 21 mmHg, or a bilateral IOP difference of ≥5 mmHg). 6. Only one eye meets the inclusion criteria. 7. Active corneal infections such as bacterial, fungal, viral, or other acute or chronic anterior segment inflammations. 8. Currently using medications that may lead to dry eye or affect vision and corneal curvature. 9. Other ocular conditions, such as dacryocystitis, eyelid disorders and abnormalities, abnormal intraocular pressure, and glaucoma. 10. Unable to undergo regular eye examinations.

Outcomes

Primary Outcomes

Ocular Fundus Blood Flow

The study measured the sub foveal choroidal thickness, superficial vessel complex (SVC) density, and deep vessel complex (DVC) density, analyzing changes in retinal blood flow under the two modes.

Time frame: The total duration of the visual task is 50 minutes. Retinal blood flow is measured for each subject at 0 minutes, 25 minutes, and 50 minutes during the visual task, resulting in a

Secondary Outcomes

Visual fatigue

The visual fatigue questionnaire utilized in this study consists of a self-report survey with a total of 19 items. It is designed to comprehensively assess the severity of visual fatigue symptoms, with a scoring system ranging from 1 to 7. Higher scores indicate more severe symptoms, encompassing three primary domains: ocular symptoms, visual discomfort, and psychological aspects triggered by visual fatigue.

Time frame: Each participant will complete the visual fatigue questionnaire, followed immediately by a VEP task, and then re-assess visual fatigue immediately afterward. This sequence will occur twice per group, totaling eight assessments per participant.

Measurement of Accommodative Sensitivity with Flip-Chart Post-VEP Tasks

This clinical study involves the assessment of accommodative sensitivity for both monocular and binocular vision using a flip-chart immediately following each visual evoked potential (VEP) task. The measurement will quantify the number of optotypes correctly identified within one minute, indicative of the subject's accommodative capacity.

Time frame: Each participant will have five measurements: a baseline, and four post-VEP tasks, with immediate flipchart tests after each task.

Blink Frequency

Use electronic devices to record the number of clicks within 3 minutes and calculate the frequency.

Time frame: Blink frequency 3 minutes after the start of each visual evoked task and 3 minutes before the end.

Reading efficiency

The number pairs were read in the first and last 5 minutes of the visual evoked task, and the number of number pairs read per minute was counted.

Time frame: The test was recorded 5 minutes after the start and 10 minutes before the end.

AC/A Ratio Measurement Post-VEP Tasks

This study involves the measurement of the AC/A ratio, which is a critical parameter in binocular vision assessment, reflecting the relationship between accommodation (focus adjustment) and convergence (ocular alignment). The AC/A ratio will be determined using the prism bar technique, which involve adding lenses to stimulate accommodation and measuring the resulting changes in convergence.

Time frame: Each participant will undergo five AC/A ratio measurements: at baseline and immediately after each of four VEP tasks.