Accommodative Lag Persistence in Treated Anisometropic, Strabismic, and Mixed Amblyopia.

Purpose:To report retinal nerve fiber layer thickness (RNFLT) in eyes with amblyopia compared with contralateral healthy eyes.Methods:In this cross-sectional study, we included patients with anisometropic amblyopia, strabismic amblyopia, and mixed amblyopia. All subjects underwent complete ophthalmic examination, including RNFLT measurement with time-domain OCT (Stratus OCT) and scanning laser polarimeter (GDX VCC). A paired “t” test was used to compare average and quadrant-wise RNFL thickness between the amblyopic and contralateral normal eyes. In addition, an analysis of variance test was used to compare various RNFL thickness parameters between the three groups.Results:A total of 33 eyes of 33 subjects with anisometropic amblyopia, 20 eyes of 20 subjects with strabismic amblyopia, and 38 eyes of 38 subjects with mixed amblyopia were included. In the anisometropic amblyopia group, the average RNFLT in the amblyopic eye was 98.2 mm and 99.8 mm in the fellow normal eye (P = 0.5), the total foveal thickness was 152.82 mm (26.78) in the anisometropic eye and 150.42 mm (23.84) in the fellow eye (P = 0.38). The difference between amblyopic and contralateral normal eye for RNFL and macular parameters was statistically insignificant in all three groups. The RNFL thickness in four quadrants was similar in the amblyopic and non-amblyopic eye between all three groups and statistically non-significant.Conclusion:Our study showed that RNFL thickness was similar in amblyopic and non-amblyopic eyes between all three amblyopia groups.

Amblyopia Characterization, Treatment, and Prophylaxis

Introduction We aim to compare retrobulbar blood flow parameters between the amblyopic eye and the fellow eye in patients with anisometropic amblyopia. Methods Peak systolic velocity (PSV) and end-diastolic velocity (EDV) of the ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery (PCA) were measured by color Doppler imaging (CDI), and the resistivity index (RI) and pulsatility index (PI) were calculated in 62 patients aged 12-40 years with anisometropic amblyopia. Results The mean PSV values of OA, CRA, and PCA in amblyopic and fellow eyes were 30.38 ± 10.34, 8.45 ± 2.27, and 8.03 ± 2.77, and33.73 ± 14.46, 8.35 ± 2.05, and 8.81 ± 2.77, respectively. The mean EDV values of OA, CRA, and PCA in amblyopic and fellow eyes were 6.86 ± 2.64, 1.47 ± 1.59, and 1.94 ± 2.03, and 8.57 ± 4.30, 1.80 ± 1.73, and 2.32 ± 1.20, respectively. The mean RI values of OA, CRA, and PCA in amblyopic and fellow eyes were 0.77 ± 0.10, 0.85 ± 0.14, and 0.78 ± 0.15, and 0.75 ± 0.07, 0.79 ± 0.20, and 0.74 ± 0.13, respectively. OA-PSV and OA-EDV values were significantly lower in the amblyopic eye than in the healthy eye (p < 0.05). OA-RI values were significantly higher (p < 0.05) in the amblyopic eye than in the healthy eye. Conclusions Considering the decrease in PSV and EDV and the increase in RI, which are the blood flow parameters of the amblyopic eye, our study may provide guidance to focus on increasing blood flow in the treatment of amblyopia.

Purpose : The purpose of this study was to measure binocular accommodative response when hyperopic and myopic anisometropia were induced on non-dominatn eye.Methods : Twenty participants (mean age: 24.05±1.73) who had corrected visual acuity more than 0.0 logMAR and no eye disease or systemic disease were recruited. The contact lenses with +1.00, +2.00, -1.00, -2.00 D were monocularly worn on non-dominant eye. The accommodative responses were measured by a binocular open-field autorefractometer when participant fixates target (accommodative stimulus) at 300, 40, and 20 cm.Results : As the accommodative stimulus distance decreased, the amount of accommodative response increased in both eyes (p<0.050). There was significant difference of accommodative responses by different degree of anisometropia (p<0.050). When –2.00 D hyperopic anisometropia was induced, both eyes showed the highest accommodative responses at 40 cm (dominant eye 1.50±0.11 D, non dominant-eye 1.71±0.09 D). When comparing accommodative responses by the type of anisometropia, there was a significant differences in both the dominant and nondominant eyes at 20 cm when inducing 1.00 and 2.00 D in myopic and hyperopic anisometropia (p<0.050). At 40 cm, there was a significant differences in both the dominant and non-dominant eyes when inducing 1.00 in myopic and hyperopic anisometropia (p<0.050). In addition it showed that the higher the degree of myopia and hyperopia, the higher the difference in accommodative response on both eyes and the difference was significant between 40 and 20 cm (p<0.050).Conclusion : There is a difference in the amount of accommodative response between dominant and non-dominant eye when anisometropia was induced. Regardless of the type, the environment that causes the difference in the amount of accommodative response between both eyes causes eye fatigue, so to prevent such a situation, not only the examination on accommodative response of both eyes, but also regular and continuous management is necessary. Also, a prescription for glasses and addition considering the difference between the two eyes is required.

Purpose: This study investigated the short-term effects of text size on an OLED display on the accommodation and pupillary responses of individuals with pre-existing digital eye strain. The hypothesis was that text size would affect the dynamics of accommodation and pupillary response.Design: Prospective Qasi-experimental study (non-randomized clinical trial)Methods: This study was conducted in a single hospital setting. A total of 324 patients were screened for digital eye strain using a validated questionnaire. Forty-six participants who met the inclusion criteria were enrolled, including having no history of digital eye strain, being young, and having no ocular problems contributing to binocular vision or digital eye strain. The dynamic accommodative response and pupillary motility of the participants' dominant eye were continuously measured using an automatic refractometer as they read text passages of three different font sizes, each for two minutes. The study was conducted under normal office lighting conditions of 400 lux, with screen brightness maintained at 400 lux and 100% letter contrast. Participants viewed the text from a fixed distance of 50 cm.Results: Repeated-measures ANOVA was used to examine whether accommodation response and pupillary response differed across the three different font sizes. Results showed that font size significantly affected both pupillary dynamics and accommodation response, with statistical significance at p &lt; .001. Specifically, larger font sizes were associated with shorter accommodation latencies and better pupil responses, while the smaller font size of 12 points resulted in higher accommodation latencies and poorer pupil responses.Conclusion: Using larger font sizes on digital displays may improve eye function for people with digital eye strain. This may reduce their symptoms, as accommodation lag is a major cause of eye strain. Smaller text sizes increase eye strain because accommodation lag is worse with smaller fonts. Adjusting font size is an important way to manage digital eye strain.

Abnormal cortical processing of pattern motion in amblyopia: Evidence from fMRI

Purpose: This study was conducted to evaluate the accommodative response in young participants with visual impairment in comparison with visually normal participants. Methods: Fifteen participants with confirmed visual impairment and 30 visually normal participants aged 12–15 years were recruited. Accommodative response was measured using autorefractor (Grand Seiko WV500) at distances of accommodative demand of 33, 25, and 20 cm. The targets were one-line-above participant threshold acuity. The participants’ accommodative responses were compared between both groups after calibration for refractive errors and the vertex distance of the glasses. Visual acuity and refractive status were also assessed. Results: The age was not significantly different between both participant groups. The visual acuity of visually impaired patients was 6/30 to 6/240, and that of visually normal participants was 6/7.5 or better. Ten of the visually impaired patients and 29 of visually normal participants were myopic. In total, 61–73% of visually impaired patients showed an accommodative lead. Five subtypes of accommodative response were observed. In general, the accommodative inaccuracy increased with increasing accommodative demand. However, the visually normal participants largely exhibited an accommodative lag. A mild-to-moderate relationship was observed between visual acuity and accommodative response (r = 0.3–0.5, p < 0.05). Conclusion: Accommodative response in young visually impaired patients can be variable and on an individual basis. Low vision specialists should anticipate accommodative response outside the normal range. Therefore, we shall consider evaluating each patient’s accommodative response before prescribing any near addition lenses. Accommodation inaccuracy is often more complex than predicted due to increased depth of focus caused by reduced visual acuity.

Previous studies in children report reduced accommodative responses with minus lens-stimulated demands compared with proximal demands. This study seeks to identify age-related changes in accommodative lag with minus lens-stimulated demands in subjects from preschoolers to adults. Accommodative responses were measured in 101 subjects (3 to 40 years) with at least 10 subjects in each 5-year age bin. Subjects monocularly viewed a high-contrast target at 33.3 cm on the near-point rod of the Grand Seiko autorefractor. Measurements of refraction were taken as the subject viewed the target. Accommodative lag was defined as the difference between demand and measured response. Four additional demands were tested by introducing minus lenses [-1 to -4 diopter (D)] in the spectacle plane of the viewing eye. Maximum accommodative amplitudes were determined by presenting additional lenses until the measured response plateaued or peaked. Accommodative demands and responses were adjusted to the corneal plane. RESULTS.: Accommodative lag showed a significant linear decrease with age for subjects 3 to 20 years for each of the first four demands (3 D, 3.92 D, 4.80 D, 5.67 D, p <or= 0.013) and approached significance for the largest demand (6.52 D, p = 0.053). For the entire group, accommodative lag increased with increasing stimulus demand, with the largest increase occurring for subjects aged 30 to 40 years as stimulus demands approached the subjects' maximum amplitude. For subjects aged 3 to 20 years, multilevel modeling analysis revealed a significant relationship between age and lag (p < 0.0001) and a significant relationship between maximum amplitude and the increase in lag per unit increase in stimulus demand (p = 0.0032). These findings suggest the accuracy of accommodation to minus lens-stimulated accommodation improves throughout the school years and that the degree to which lag increases with increasing demand is related to maximum accommodative amplitude rather than age.

Studies in nonhuman primates show that monocular visual deprivation starting at different ages has different effects on cells in the parvocellular and magnocellular laminae of the lateral geniculate nucleus. The present study used color and luminance contrast sensitivity (CS) measurements to look for differences in parvocellular- and magnocellular-related visual function in human subjects with strabismic amblyopia. Fifteen subjects with early- and 14 with late-onset strabismic amblyopia and similar ranges of visual acuity were studied, together with 15 subjects with normal vision. Contrast sensitivities were measured to an equiluminant (L-M cone-modulated) grating with slow onset and an achromatic (L+M cone-modulated) 0.8-cpd grating with rapid onset using an adaptive Luminance and color CS were lower in the amblyopic eyes than in the fellow eyes of all amblyopes. For luminance CS, this was due both to an increase in sensitivity of the fellow eye and to a reduction in sensitivity in the amblyopic eye. Color CS was greatly reduced in the amblyopic and fellow eyes of subjects with strabismic amblyopia of early- and late onset compared with subjects with normal vision. The reduction in color CS compared with luminance CS was significantly greater in eyes with late- rather than early-onset amblyopia. Parvocellular and magnocellular function are differentially affected in the amblyopic and fellow eyes of subjects with strabismic amblyopia. The difference is more marked in late-onset amblyopia than in early-onset amblyopia.

Objective: To evaluate the accommodative facility and accommodative response in patients with intermittent exotropia. Methods: Thirty-five patients with basic intermittent exotropia and 24 normal controls were recruited for a case control study at Eye Hospital, Wenzhou Medical University from October 2016 to January 2017. Binocular and monocular accommodative facility were tested using a ± 2.00 diopter (D) flip. Accommodative responses under binocular and monocular viewing conditions at 40 cm were tested by an open-field autorefractor WAM-5500. Data were analyzed using t-tests. Results: The binocular accommodative facility of intermittent exotropia was 8.8 ± 4.1 cycles per minute (cpm), which was significantly lower than the normal control, 10.9 ± 3.1 cpm (t=-2.165, P=0.035). The fixating eye of intermittent exotropia had higher monocular accommodative facility than the non-fixating eye (t=4.657, P<0.001). Under binocular viewing conditions, the fixating eye of the intermittent exotropia had a higher accommodative response than the fixating eye of the normal control (t=-2.163, P=0.035). The binocular accommodative response was also higher than the accommodative response under monocular viewing conditions (t=3.801, P=0.001). Conclusions: Patients with intermittent exotropia have low binocular accommodative facility. They also have asymmetric monocular accommodative facility and asymmetric accommodative responses between the fixating eye and the deviating eye. Patients with intermittent exotropia have a higher accommodative response under binocular viewing conditions than under monocular viewing conditions. Key words: intermittent exotropia; accommodative facility; accommodative response

To measure the changes in astigmatism and in the degree of anisometropia when ametropes respond to accommodative stimulation. The accommodative responses of ametropes were binocularly measured with an improved photorefractometer (PR-1100), which objectively measured binocular refraction in all meridians simultaneously, when a visual fixation target was shown in natural space at 5 and 0.5 m. (1) Changes of astigmatism and anisometropia occur during binocular accommodation. (2) Changes of astigmatism mainly result from lag of accommodation in the horizontal meridian. (3) Changes of anisometropia result from the effort to focus. (4) The interaction of both eyes is suggested as the cause of the changes of astigmatism and anisometropia with accommodation. (5) In the majority of strong anisometropes (nonoverlapping group in this paper), the magnitude of anisometropia decreases (approaching isometropia) with accommodation. Changes in astigmatism and anisometropia can occur during accommodation, and these interactions of both eyes with accommodation may contribute to the development and maintenance of binocular function.

To investigate the contribution of the individual ocular components, i.e. anterior chamber depth, lens thickness and vitreous chamber depth, to total axial length in patients with esotropic amblyopia. The study population consisted of 74 children, aged between 5 and 8 years: thirty-seven patients with esotropic amblyopia and 37 healthy volunteers (control group). The participants underwent a comprehensive ophthalmological examination, including cycloplegic refraction and A-scan ultrasonography. Anterior chamber depth, lens thickness, vitreous chamber depth and total axial length were recorded. Paired Student's t-tests were used to compare biometric measurements between amblyopic eyes and their fellow eyes and between right and left eyes in the control group. To evaluate the contribution of the ocular components to the total axial length, we report the individual components as a percentage of total axial length. The comparison between amblyopic and fellow eyes regarding the individual contribution from ocular components to the total axial length revealed greater contribution from lens thickness (P=0.001) and smaller contribution from vitreous chamber depth (P=0.001) in amblyopic eyes, despite similar contribution from anterior chamber depth (P=0.434). The comparison between right and left eyes in the control group showed similar contributions from anterior chamber depth (P=0.620), lens thickness (P=0.721), and vitreous chamber depth (P=0.483). This study shows differences between amblyopic and non-amblyopic eyes when the total axial length is broken down into the individual contribution from the ocular components.

Successful Treatment of Anisometropic Amblyopia with Spectacles Alone

To determine whether or not myopic children have a larger lag of accommodation than emmetropic children under natural seeing conditions. In 61 myopic children (age, 9.5 +/- 1.3 years; spherical equivalent refractive error, -6.50 to -1.00 D), accommodative response was objectively measured while they were binocularly viewing a target at 50.5, 32.5, 20.9, or 16.0 cm (1.98-6.25 D) through fully correcting glasses. In the 33 children who habitually wore spectacles, the accommodative responses were also measured while they wore their own spectacles. As controls, 18 emmetropic children were recruited. Accommodative response gradients and lags were compared between the groups after calibration for residual refractive errors and the vertex distance of the glasses. With fully correcting glasses, the myopic children showed a larger mean lag of accommodation than the emmetropic children, as well as wide intersubject variation. However, when the children wore their habitual, usually undercorrecting, spectacles, accommodative lags markedly decreased, and a significant correlation was found between residual refractive errors after correcting for the spectacles and accommodative lags. Myopic children with near-point exophoria tended to show smaller lags of accommodation. Under binocular viewing conditions, myopic children when viewing the target through fully correcting glasses tend to show larger lags of accommodation than emmetropic children, but the lags of accommodation are usually reduced by their spectacle undercorrection.

Purpose: To evaluate the factors influencing visual outcome in strabismic, strabismic-anisometropic and anisometropic amblyopia following occlusion treatment. Methods: Records of 128 pediatric patients who had been treated for amblyopia by occlusion of the fellow eye between March 1992 and March 2003 were reviewed retrospectively. Age and level of visual acuity at initiation of treatment, occlusion time (full-time, part-time or minimal) and type of amblyopia were analyzed for the effect on visual outcome. Results: The mean age of the patients was 5.69 ± 2.01 years (3 to 12 years). Mean follow-up time was 3 years 2 months (6 months to 10 years). Mean visual acuity improvements were similar for the subtypes of amblyopia (strabismic amblyopia 0.38 ± 0.29 logMAR units, strabismic-anisometropic amblyopia 0.46 ± 0.40 logMAR units, anisometropic amblyopia 0.35 ± 0.24 logMAR units). Level of initial visual acuity, age at initiation of treatment and type of occlusion correlated with the final visual acuity (p = 0.000, p = 0.035, p = 0.012, respectively). When the analysis was performed according to the subtypes of amblyopia, initial visual acuity was the only factor associated with the final visual acuity in all types of amblyopia (p < 0.05). Conclusion: The level of initial visual acuity is the most significant factor determining the success of treatment in amblyopia.