快速序列视觉呈现方式阅读状态下不同屈光组调节反应的差异

目的研究快速序列视觉呈现方式（rapid serial visual presentation．RSVP）阅读状态下进展性近视、稳定性近视和正视之间调节反应的差异，探讨调节因素在近视发生、发展过程中的表达。方法45例受试者参加本实验，分为进展性近视、稳定性近视和正视组，各15例。阅读材料为位于距受试者左眼角膜平面25cm处的电脑显示屏上的一篇中文短文．通过RSVP软件呈现单个字符．字体大小为9pt，文字呈现速度为150字／min。使用SEIKO—WV500自动验光仪测量其开放视野阅读状态下左眼的调节反应。结果所有受试者在4D的调节刺激下，均存在一定程度的调节滞后，个体差异较大。进展性近视组的调节反应低于正视组[（2．32±0．43）0VS（3．19±0．53）0，P〈0．01]，进展性近视组的调节反应亦低于稳定性近视组[（2．32±0．43）0VS（3.07±0．34）D，P〈0．01]，而正视组和稳定性近视组差异无显著性（P=0．441）。结论近距离阅读状态下进展性近视有较高的调节滞后，远视性离焦造成的模糊斑可能是近视的发生发展的促成因素，随着近视发展的稳定．调节反应恢复至一般水平。     

不同阅读距离对儿童近视调节反应的影响

目的研究不同阅读距离对儿童近视调节反应的影响,推测它和近视发生的可能关系。方法应用Shin-NipponNVision-K5001红外线自动验光仪,在阅读距离分别为50cm、33cm、20cm时,测量77例7岁～14岁近视儿童的调节状态。结果在阅读距离为50cm、33cm、20cm时,所需的调节需求分别为(1.90±0.03)D、(2.85±0.05)D和(4.75±0.08)D;调节反应分别为(0.87±0.42)D、(1.76±0.54)D、(3.52±0.66)D,调节滞后则为(1.03±0.36)D、(1.08±0.52)D、(1.23±0.63)D。在近距离阅读中,儿童近视者的调节反应均表现为调节滞后,且随着阅读距离减小,调节滞后增加;三个不同阅读距离间的调节滞后差别有统计学意义(P=0.014),其中50cm与20cm、33cm与20cm的阅读距离的调节滞后差别有统计学意义(P<0.05)。结论阅读距离为儿童近视者的调节反应影响因素之一,阅读距离越近者调节滞后越明显,形成远视性离焦越明显,从而可能导致儿童近视的加深。     

近视青少年在阅读状态下调节反应和像差的研究

背景近距离工作时,视网膜的成像质量受调节、瞳孔和像差的共同影响;而近距离工作时视网膜成像的清晰度又被认为是青少年近视发生发展的可能诱因。因此,研究近视及正视青少年在阅读状态下的眼动参数和像差的差异性显得尤为重要。目的研究有初发性近视和进展性近视的青少年在阅读状态下的调节反应、瞳孔直径和像差的差异,从视网膜离焦诱导近视和像差诱导近视这两个假说探讨调节反应和像差与近视发生发展的相关机制。方法57例年龄12～16岁青少年受试者分为正视组16眼、初发性近视组20眼和进展性近视组21眼。嘱受试者阅读左眼前25effl处电脑显示屏上由快速序列视觉呈现方式软件所呈现的一篇中文短文,用SEIKO—WV500型自动验光仪测量调节反应,实时录像记录瞳孔直径,并用WASCA波前像差仪测量像差,对3组间的结果进行比较。结果各组受试者的调节反应和像差的个体差异均较大,在4D的调节刺激下,初发性近视组和进展性近视组的调节滞后值为（1．72±0．53）D,（1．74±0．44）D,高于正视组的（0．96±0．55）D,差异有统计学意义（t=4．25、t=4．47,P〈0．01）。初发性近视组和进展性近视组的调节滞后差异无统计学意义（t=0．18,P〉0．05）。调节刺激在0～4D时,所有受试者的瞳孔直径、全眼像差、高阶像差、球差和彗差均随着调节力的增加而显著减小（P〈0．01）,但在同一调节刺激下,不同屈光组之间受试者的瞳孔直径、全眼像差、高阶像差、球差和彗差的差异均无统计学意义（P〉0．05）。结论初发性近视和近视进展过程中在近距离阅读状态下存在较高的调节滞后,近距离阅读状态下对离焦的低模糊敏感性、较高的调节滞后及远视性离焦可能是近视发生、发展的促进因素。     

近视眼不同屈光状态下调节反应量的观察

目的 分析青年人群中近视眼调节功能与正视眼的差异.方法 根据等效球镜度数的不同,将55例(110眼)受试者分为正视组(24眼)、低度近视组(25眼)、中度近视组(36眼)和高度近视组(25眼).使用GRAND-SEIKO WAM-5500开放视野式自动验光仪测量3 D调节刺激下诱发的调节反应量,比较正视眼和低、中、高度...     

不同调节视标下调节反应的比较

目的分析人眼在马耳他十字视标(Maltese cross)、E视标及快速序列视觉呈现(rapid serial verbal presentation,RSVP)系统汉字三种调节视标下的调节反应,探讨注视状态和阅读状态调节反应的差异。方法31位志愿者参加本实验,其中正视15位,等效球镜屈光力为-0.25～ 0.50D;近视16位,均为稳定性近视,等效球镜屈光力为(4.06±2.00)D。利用精工SEIKO-WV500开放视野式自动验光仪测量调节反应,比较33cm处不同调节视标下,注视状态和阅读状态调节反应的差异。结果Maltesecross视标、E视标、RSVP汉字视标作为调节视标,调节反应分别为(2.07±0.35)D、(2.08±0.30)D、(1.88±0.42)D。其中RSVP汉字视标与E视标相比较,调节反应的差异有显著性(P=0.001),RSVP汉字视标与Maltese cross视标相比,调节反应的差异亦有显著性(P=0.003),而Maltese cross视标与E视标之间,调节反应差异无显著性。RSVP汉字作为调节视标时,个体间存在较大差异。不同调节视标下,正视组和稳定性近视组之间的调节反应均无显著差异。结论RSVP中汉字作为调节视标,在模拟阅读状态时和在低注意力情况下正自主性调节成分减少,调节反应降低。     

角膜塑形镜和框架眼镜对青少年调节反应的影响

目的研究青少年近视患者应用角膜塑形镜矫治调节反应的改变。方法 110例青少年近视分为两组,角膜塑形镜组55例和框架眼镜组55例。应用分光检影设备对两组患者初次戴镜,及戴镜12月后双眼调节反应进行测定,同时计算调节滞后量,并统计分析。结果初次戴镜,角膜塑形镜组调节反应改变及调节滞后,同框架眼镜组相较差异不显著,P>0.05。戴镜12月后,角膜塑形镜组与框架眼镜组比较,调节反应改变和调节滞后均有明显差异,P<0.05。戴镜12月后同初次戴镜相较,角膜塑形镜组调节反应改变及调节滞后无显著差异,框架眼镜组则差异明显,P<0.05。结论青少年近视患者应用角膜塑形镜矫治,调节反应的改变明显大于应用框架眼镜矫治,而调节滞后低于框架眼镜矫治。     

阅读界面和方式对调节反应的影响研究

目的：：比较电脑阅读、手机阅读、纸张阅读条件下,调节反应的差异。探讨不同阅读界面、阅读距离以及亮度对调节反应的综合影响。方法：设置电脑、手机和纸张阅读界面,选取30位青年志愿者,分别在电脑(电脑提供两种不同亮度)、手机以及纸张状态下,使用Grand Seiko WAM 5500红外自动验光仪测调节反应以及瞳孔大小。用SPSS17.0将结果进行方差分析,比较不同阅读条件对人眼调节的影响。结果：电脑屏幕正常亮度下的调节滞后为0.52±0.24D,纸张视标下调节滞后为0.73±0.28D,手机视标下调节滞后为0.72±0.29D。电脑正常亮度屏幕下的调节滞后显著小于手机和纸张视标下的调节滞后量,且均有统计学差异(P<0.05),而手机和纸张视标下调节滞后量无统计学差异。手机阅读引起人眼的调节微波动和瞳孔波动略大于电脑屏幕和纸张,但结果无统计学差异。结论：人眼在阅读电脑屏幕时调节滞后显著小于手机和纸张,后二者则没有显著区别。电脑屏幕亮度在一定程度内的变化并不影响调节反应。     

青少年近视在不同阅读距离调节状态下眼前段结构的变化

目的分析和探讨不同程度青少年近视在不同阅读距离诱导的调节状态下眼前段结构的变化。方法收集我院屈光门诊14～18岁间青少年近视95例（95眼），正视眼34例（34眼）作对照，其中男66例，女63例。所有被试者行主觉验光、调节幅度测定，眼前节OCT测量在不同阅读距离诱导的调节状态下（OD、3D、6D）的前房深度、晶状体厚度及瞳孔直径，采用SPSS11．5forWindows行统计学分析。结果①在调节放松情况下，随着近视度数增加，暗瞳直径明显减小（P〈0．05），各组间晶状体厚度差异无显著性，前房深度差异有显著性（P〈0．05）。（D随着阅读距离的减小，调节运用的增加，各组前房深度变浅值、晶状体厚度变厚值、暗瞳直径变小值均显著增加（P〈0．01）。③随着近视度数增高，诱发3D调节时前房深度变浅值显著增加（P〈0．01），晶状体厚度变厚值明显增加（P〈0．05），暗瞳直径变小值差异无显著性。④随着近视度数增高，诱发6D调节时前房深度变浅值显著增加（P〈0．01），晶状体厚度变厚值明显增加（P〈0．05），暗瞳直径变小值显著增加（P〈0．01）。结论在青少年中，随近视程度加深，阅读距离减小，运用调节量的增加可引起眼前房显著变浅，晶状体明显变厚：暗瞳直径缩小值在诱发6D调节时随近视度数增高而增大。     

初发近视儿童调节反应与近视屈光度的关系

目的 探讨初发近视儿童调节反应与近视屈光度的关系。设计 回顾性病例系列。研究对象 北京同仁验光配镜中心视力下降在6个月内的8～10岁儿童96例,复方托吡卡胺散瞳测双眼近视低于-1.00 D。方法 散瞳前采用综合验光仪进行调节反应、调节灵活度以及正、负相对调节检查。选取双眼中较低度数眼的参数进行统计学分析。主要指标 屈光度、调节反应、调节灵活度、正负相对调节。结果 受试者屈光度为（-0.66±0.25）D,调节反应为（0.25±0.36）D;调节灵活度为（6.31±2.54）cpm;负相对调节为（2.20±0.40）D;正相对调节为（-1.96±1.32）D。调节反应与近视屈光度呈负相关（r=-0.34,P=0.001）;调节反应与调节灵活度、负相对调节无相关性（r=0.027,P=0.798,r=-0.140,P=0.174）;调节反应与正相对调节呈正相关（r=0.231,P=0.023）。结论 初发近视儿童已存在调节反应滞后,调节反应滞后和正相对调节的降低,可能是近视发生发展的原因。（眼科, 2014, 23: 319-322）     

开环状态下调节的暗焦点研究进展△

正常情况下,人眼调节系统可利用闭环负反馈系统进行精确的调节反应,而在缺乏足够的视觉刺激时,反馈回路被打破,在开环状态下的调节系统趋向于返回其 “静息”位置(暗焦点),导致人眼的屈光状态趋于近视。目前有研究认为近距离用眼后暗焦点会发生变化,可能与长时间近距离工作引发的近视相关。本文结合相关文献报道,对暗焦点的测量技术、自身特点及其在近视防控中的应用前景等方面进行综述,以期为临床工作及相关研究提供参考。     

The effect of blur adaptation on accommodative response and pupil size during reading

To study the effect of blur adaptation on accommodative variability, accommodative responses and pupil diameters in myopes (n = 22) and emmetropes (n = 19) were continuously measured before, during, and after exposure to defocus blur. Accommodative and pupillary response measurements were made by an autorefractor during a monocular reading exercise. The text was presented on a computer screen at 33 cm viewing distance with a rapid serial visual presentation paradigm. After baseline testing and a 5-min rest, blur was induced by wearing either an optimally refractive lens, or a +1.0 DS or a +3.0 DS defocus lens. Responses were continuously measured during a 5-min period of adaptation. The lens was then removed, and measurements were again made during a 5-min post-adaptation period. After a second 5-min rest, a final post-adaptation period was measured. No significant change of baseline accommodative responses was found after the 5-min period of adaptation to the blurring lenses (p > 0.05). Compared to the pre-adaptation level, both refractive groups had similar and significant increases in accommodative variability right after blur adaptation to both defocus lenses. After the second rest period, the accommodative variability in both groups returned to the pre-adaptation level. The results indicate that blur adaptation has a short-term effect on the accommodative system to elevate instability of the accommodative response. Mechanisms underlying the increase in accommodative variability by blur adaptation and possible influences of the accommodation stability on myopia development were discussed.     

A comparison of reading,in people with simulated and actual central vision loss,with static text,horizontally scrolling text,and rapid serial visual presentation

Reading with central vision loss (CVL), as caused by macular disease, may be enhanced by presenting text using dynamic formats such as horizontally scrolling text or rapid serial visual presentation (RSVP). The rationale for these dynamic text formats is that they can be read while holding gaze away from the text, potentially supporting reading while using the eccentric viewing strategy. This study was designed to evaluate the practice of reading with CVL, with passages of text presented as static sentences, with horizontal scrolling sentences, or as single-word RSVP. In separate studies, normally sighted participants with a simulated (artificial) central scotoma, controlled by an eye-tracker, or participants with CVL resulting from macular degeneration read passages of text using the eccentric viewing technique. Comprehension was better overall with scrolling text when reading with a simulated CVL, whereas RSVP produced lower overall comprehension and high error rates. Analysis of eye movement behavior showed that participants consistently adopted a strategy of making multiple horizontal saccades on the text itself. Adherence to using eccentric viewing was better with RSVP, but this did not translate into better reading performance. Participants with macular degeneration and an actual CVL also showed the highest comprehension and lowest error rates with scrolling text and the lowest comprehension and highest errors with RSVP. We conclude that scrolling text can support effective reading in people with CVL and has potential as a reading aid.     

The influence of accommodative insufficiency on reading

Background: It is not known how accommodative insufficiency influences reading performance. Methods: Reading eye movements were recorded before and after treatment for accommodative insufficiency in 12 school children (eight to 16 years). During the eight‐week treatment period all subjects wore a +1.00 D addition when reading. Results: Large variations in reading patterns were found. Despite successful accommodative treatment (p < 0.001), no correlation was found to suggest improved reading velocity. Discussion: Three case reports will be presented and the implications discussed.     

Age factor affects reading acuity and reading speed in attaining text information

AIM: To investigate the effect of age on reading acuity and reading speed in attaining text information in healthy eyes. METHODS: Reading acuity, critical print size, reading speed and maximum reading speed were measured in groups of 40 children (8 to 12 years old), 40 teenagers (13 to 19 years old), 40 young adults (20 to 39 years old), and 40 adults (40 years old and above) using the Buari-Chen Malay Reading Chart [contextual sentences (CS) set and random words (RW) set] in a cross-sectional study design. RESULTS: Reading acuity was significantly improved by 0.04 logMAR for both CS set and RW set from children to teenagers, then gradually worsened from young adults to adults (CS set: 0.06 logMAR; RW set: 0.08 logMAR). Critical print size for children showed a significant improvement in teenagers (CS set: 0.14 logMAR; RW set: 0.07 logMAR), then deteriorated from young adults to adults by 0.09 logMAR only for CS set. Reading speed significantly increased from children to teenagers, [CS set: 46.20 words per minute (wpm); RW set: 42.06 wpm], then stabilized from teenagers to young adults, and significantly reduced from young adults to adults (CS set: 28.58 wpm; RW set: 24.44 wpm). Increment and decrement in maximum reading speed measurement were revealed from children to teenagers (CS set: 39.38 wpm; RW set: 43.38 wpm) and from young adults to adults (CS set: 22.26 wpm; RW set: 26.31 wpm) respectively. CONCLUSION: The reference of age-related findings in term of acuity and speed of reading should be incorporated in clinical practice to enhance reading assessment among healthy eyes population.     

Characteristics of accommodative behavior during sustained reading in emmetropes and myopes

Accommodation has long been suspected to be involved in the development of myopia because near work, particularly reading, is known to be a risk factor. In this study, we measured several dynamic characteristics of accommodative behavior during extended periods of reading under close-to-natural conditions in 20 young emmetropic and stable myopic subjects. Accommodative responses, errors, and variability (including power spectrum analysis) were analyzed and related to accommodative demand and subject refractive error. All accommodative behaviors showed large inter-subject variability at all of the reading demands. Accommodative lags and variability significantly increased with closer demands for all subjects (ANOVA, p<0.05). Myopes had significantly greater variability in their accommodation responses compared to emmetropes (ANOVA, p<0.05) and had larger accommodative lags at further reading distances (unpaired t test p<0.05). Power spectrum analysis showed a significant increase in the power of accommodative microfluctuations with closer demands (ANOVA, p<0.05) and with increasing myopia at the closest reading demand (ANOVA, p<0.01). The difference in the stability of the accommodative behavior between individuals with different refractive states suggests a possible relationship between variability in accommodation and the development of myopia.     

The size and direction of saccadic curvatures during reading

Eye movements during the reading of multi-line pages of texts were analyzed to determine the trajectory of reading saccades. The results of two experiments showed that the trajectory of the majority of forward-directed saccades was negatively biased, i.e., the trajectory fell below the start and end location of the saccadic movement. This is attributed to a global top-to-bottom orienting of attention. The curvature size and the proportion of negative trajectories were diminished when linguistic processing demands were high and when the beginning lines of a page were read. Longer pre-saccadic fixations also yielded smaller saccadic curvatures, and they resulted in fewer negatively curved forward-directed saccades in Experiment 1 although not in Experiment 2. These findings indicate that the top-to-bottom pull of saccadic trajectories is modulated by processing demands and processing opportunities. The results are in general agreement with a time-locked attraction-inhibition hypothesis, according to which the horizontal movement component of a saccade is initially subject to an automatic top-to-bottom orienting of attention that is subsequently inhibited.     

Eye movements during reading of randomly shuffled text

In research on eye-movement control during reading, the importance of cognitive processes related to language comprehension relative to visuomotor aspects of saccade generation is the topic of an ongoing debate. Here we investigate various eye-movement measures during reading of randomly shuffled meaningless text as compared to normal meaningful text. To ensure processing of the material, readers were occasionally probed for words occurring in normal or shuffled text. For reading of shuffled text we observed longer fixation times, less word skippings, and more refixations than in normal reading. Shuffled-text reading further differed from normal reading in that low-frequency words were not overall fixated longer than high-frequency words. However, the frequency effect was present on long words, but was reversed for short words. Also, consistent with our prior research we found distinct experimental effects of spatially distributed processing over several words at a time, indicating how lexical word processing affected eye movements. Based on analyses of statistical linear mixed-effect models we argue that the results are compatible with the hypothesis that the perceptual span is more strongly modulated by foveal load in the shuffled reading task than in normal reading. Results are discussed in the context of computational models of reading.     

Preferred retinal locus and reading rate with four dynamic text presentation formats.

BACKGROUND: Electronic display devices hold the potential to improve access to written material by people with low vision. For those with central field loss, the optimal form of electronic text presentation may vary according to the location of the preferred retinal locus, but this has never been investigated. In this study, we examined the relationship between preferred retinal locus location and reading rate for four electronic display formats (rapid serial visual presentation, horizontal scroll, vertical scroll, and page). METHODS: Short sentences were presented in each format to 35 low-vision (most with central field loss) and 14 age-matched control subjects. Subjects read aloud to determine maximum oral reading rate and read silently to determine preferred silent reading rate. RESULTS: With the exception of page format, maximum oral reading rates were faster than silent preferred reading rates for both groups of subjects. For the low-vision group, there was no significant difference in maximum oral reading rates between the four display formats; and when reading at a preferred silent rate, page format was faster than the other three formats. Though page format was read more quickly, half of the low-vision subjects preferred the horizontal-scroll format. Contrary to our predictions, there was no significant effect of preferred retinal locus location (vertical vs. lateral) on reading rate and no significant interaction between preferred retinal locus location and display format. CONCLUSIONS: The differences between maximum oral and preferred silent reading rates and the lack of a relationship between reading rates and preferred display format reinforce the importance of patient preference in the evaluation and selection of a device or display format during rehabilitation.