亞健康族群在不同照明條件下視覺功能之比較與分析

研究目的：先前文獻指出老化相關的眼部疾病與眼科手術都對中間視覺能力有所影響，但鮮少有研究聚焦介於健康與疾病狀態間的亞健康族群，本研究中的亞健康族群指在低照明條件下視力表現較差的個體，探討其在中間照明條件下視覺功能的改變以及其與眼生理之間的關聯，將有助於幫助學界釐清夜間視覺功能喪失的原因。本篇研究旨在分析造成臺灣年輕亞健康族群在中視條件下視功能表現下降之原因，並探討視功能變化與眼部生理之間的關聯性。研究方法本研究招募20~35歲之受試者，並對其進行眼生理參數收集與兩種照明條件 (明視條件：300 cd/m2；中視條件：3 cd/m2)下的視功能測量。測量項目包括低亮度問卷、貝克焦慮量表、角膜與瞳孔參數、瞳孔間距、波前像差、眼表與淚液品質、黃斑色素密度、調節能力(幅度與靈敏度)、動眼能力、聚散能力與斜位、立體視與色覺表現、光刺激恢復時間、遠近距離視力以及對比敏感度。此外，研究依照遠與近距離視力下降的幅度將受試者分為視力穩定組(Stable group, < 0.2 logMAR)與視力波動組(Unstable group, ≥ 0.2 logMAR)，並使用IBM SPSS Statistic v22 統計軟體逕行分析。研究結果至實驗截止日期共有56位受試者完成所有數據收集並納入統計分析資料，照明條件改變對大部份的視覺功能產生影響；在遠距離分組(穩定組37人、波動組19人)中，視力波動組的眼生理變項僅瞳孔反應顯著低於穩定組，視功能變項除了遠開散模糊點在波動組中較快出現外，其餘變項兩組之間皆無顯著差異。而近距離分組(穩定組45人、波動組11人)中波動組與穩定組相比，眼表保護指數、淚液破裂時間(單尾)以及瞳孔間距顯著較低；視功能方面，隨著照明條件下降波動組的調節靈敏度以及低空間頻率(3cpd)對比敏感度的下降幅度顯著高於穩定組。討論與結論遠距離波動組於中視條件下的瞳孔擴張量較低，可能降低影像清晰度，導致波動組的開散模糊點提早出現。此外，近距離波動組的瞳孔間距普遍較小，推測較低的雙眼視差刺激降低了其雙眼視覺穩定性，進而影響在低照明條件下的視覺表現。而近距離波動組的調節靈敏度與低空間頻率對比敏感度較差，這可能與其眼表狀態和淚液表現較差有關。研究證明年輕亞健康族群在中視條件下視功能表現下降與眼部生理之間有相當的關聯。

PurposePrevious studies have indicated that age-related ocular diseases and ophthalmic surgeries can affect mesopic vision. However, few studies have focused on the sub-healthy population, whose condition is intermediate between health and disease. In this study, the sub-healthy group refers to individuals who exhibit greater declines in visual acuity under mesopic conditions. This study aims to analyze the factors contributing to decreased visual function under mesopic conditions among young sub-healthy individuals in Taiwan and to explore the associations between the changes in visual function and ocular physiology.MethodsParticipants aged 20 to 35 underwent ocular physiological assessments and visual function tests under photopic (300 cd/m²) and mesopic (3 cd/m²) conditions. The assessments included a low luminance questionnaire, Beck Anxiety Inventory, corneal and pupil parameters, pupillary distance, wavefront aberrations, ocular surface and tear film quality, macular pigment optical density, accommodation (amplitude and facility), oculomotor ability, vergence and phoria, stereopsis and color vision performance, photostress recovery time, distance and near visual acuity, and contrast sensitivity. In addition, participants were classified as stable group (visual acuity change < 0.2 logMAR) or unstable group (≥ 0.2 logMAR) for both distance and near vision. Statistical analysis was performed using IBM SPSS Statistics v22.ResultsA total of 56 participants completed all data collection and were included in the statistical analysis. Changes in illumination conditions affected most visual functions. Based on distance vision (stable group: 37; unstable group: 19), the unstable group exhibited significantly reduced pupillary response compared to the stable group. Among visual function variables, only the distance divergence blur point appeared earlier in the unstable group, with no significant differences in other variables between groups. In the near vision grouping (stable group: 45; unstable group: 11), the unstable group showed significantly lower ocular surface protection index, tear break-up time (one-tailed), and pupillary distance compared to the stable group. Regarding visual function, the unstable group demonstrated a significantly greater decline in accommodative facility and low spatial frequency (3 cpd) contrast sensitivity under reduced illumination.Discussion and ConclusionUnder mesopic conditions, the distance unstable group showed smaller pupil changes that may reduce image clarity, leading to an earlier appearance of the divergence blur point. Additionally, the generally smaller interpupillary distance in the near unstable group suggests that lower binocular disparity stimuli may reduce binocular visual stability, thereby affecting visual performance under low illumination. Furthermore, the poorer accommodative facility and low spatial frequency contrast sensitivity in the near unstable group may be related to the poorer ocular surface and tear film quality. This study suggests a potential association between decreased visual function under mesopic conditions and ocular physiology in young sub-healthy individuals.