INTRODUCTIONMyopes are suspected to be poorer at responding to accommodative stimuli than emmetropes, and this may worsen the degree of their myopia. The study aims to compare the abilities of young adult emmetropes and myopes in responding to accommodative stimuli, as indicated by their Accommodation Stimulus Response Curves (ASRCs) in a predominantly Chinese population.

MATERIALS AND METHODSSeventeen emmetropes and 33 myopes aged between 16 and 23 years (mean, 18.6 +/- 1.2) were recruited, of whom 11 were progressing and 22 were non-progressing myopes. The ASRC gradients of subjects were measured using the methods of decreasing distance series (DDS), positive (PLS) and negative lens series (NLS).

RESULTSThe ASRC is method dependent. The gradients of the curves are significantly different among 3 methods of measurement using single-factor ANOVA (F3.057 = 44.815, P <0.01). The slopes of the accommodative errors of all subjects were steeper using the NLS method, and the lags of accommodation increased with elevated demands. No significant differences in ASRC gradients were found between emmetropes, non-progressing myopes and progressing myopes for the range of accommodative demands for each method. Progressing myopes showed the highest error towards the higher demand compared with the emmetropes and non-progressing myopes.

CONCLUSIONAccommodative responses of myopes were more sluggish though there were no statistical differences in ASRC gradients between emmetropes and myopes. It is not certain if the poorer accommodative responses were a cause, or a consequence, of myopia.

Accommodation, Ocular ; Adolescent ; Adult ; Disease Progression ; Female ; Humans ; Male ; Myopia ; physiopathology ; Refraction, Ocular

OBJECTIVETo test the effects of corrective spectacles in hyperopic amblyopic children with heterophoria.

METHODSVisual acuity, refraction and the amount of heterophoria on near (33 cm) fixation were measured before and after 3 weeks of spectacle-wearing in 30 hyperopic amblyopic children with heterophoria. The control group consisted of 20 emmetropic children age-matched to the patients.

RESULTSUncorrected eyes displayed hyperopic amblyopia accompanied by heterophoria. Corrective spectacles not only attenuated the hyperopia and amblyopia, but also changed the heterophoria to orthophoria. The amount of heterophoria before wearing spectacles was significantly different from that in emmetropic children; but after correction with spectacles, it was the same as that in the emmetropic controls.

CONCLUSIONCorrection with spectacles is effective for the treatment of heterophoria in hyperopic children with amblyopia.

Accommodation, Ocular ; Amblyopia ; diagnosis ; therapy ; Child ; Eyeglasses ; Humans ; Hyperopia ; diagnosis ; therapy ; Refraction, Ocular ; Vision Tests ; methods

To investigate the presence of apparent accommodation in monocular pseudopakic eyes and contact lens wearing monocular aphakic eyes, we measured it in 54 monocular pseudophakic eyes (54 patients) and 40 contact lens wearing monocular aphakic eyes (40 patients). The mean apparent accommodation was 1.68+/-1.25 diopters in monocular pseudophakic eyes and 1.74+/-0.73 diopters in contact lens wearing monocular aphakic eyes, and there was no statistically significant difference between them. Apparent accommodation was not related either to type of intraocular lenses or pupil size in pseudophakic eyes and not related to target size in aphakic eyes, but it was influenced by pupil size in aphakic eyes. In the group of patients aged between 45 and 55, accommodation in phakic eyes was significantly greater than apparent accommodation in contralateral contact lens wearing monocular aphakic eyes.
*Accommodation, Ocular ; Adolescent ; Adult ; Aged ; Aphakia, Postcataract/*physiopathology ; Child ; *Contact Lenses ; Humans ; Middle Aged

An instrument for subjective measurement of tonic accommodation has been established based on the Badal system and Scheiner principle. The results of tonic accommodation between subjective measurement and objective measurement have no significant difference. Its establishment is important for the measurement of accommodation parameter in the myopia research center.
Accommodation, Ocular ; physiology ; Diagnostic Techniques, Ophthalmological ; instrumentation ; Humans ; Optometry ; instrumentation ; methods ; Refractometry ; instrumentation ; methods ; Visual Acuity

OBJECTIVETo develop a spectral-domain optical coherence tomography (SD-OCT) system, for precisely imaging the accommodation of the anterior segment of the human eye.

METHODSDesign the SD-OCT system based on two Michelson interferometer by using the basic principal of weak coherent light interference and modular design of dual channel dual focus.

RESULTSThe system can provide simultaneous cross-sectional imaging of all the surfaces of the anterior segment of the eye including the cornea, anterior chamber, anterior and posterior surfaces of the crystalline lens. Thus, the dynamic change of modification of the curvatures can be calculated in real time.

CONCLUSIONSThe system was successfully tested in imaging accommodation, with high resolution and non contact. The preliminary results demonstrated the feasibility of this novel approach to measure the eye parameters.

Accommodation, Ocular ; Anterior Eye Segment ; physiology ; Humans ; Tomography, Optical Coherence ; methods

The authors report two cases of suddenly deteriorated accommodative esotropia with amblyopia during part-time occlusion therapy. A 7-year-old girl with right accommodative esotropia, which was well controlled, showed marked increase in esodeviation after part-time occlusion and regained orthophoria without occlusion. This phenomenon was repeated. Recession of both medial recti was performed and orthophoria was well maintained at both distant and near targets. Accommodative esotropia of a 9-year-old boy with glasses also showed a striking increase in esodeviation after part-time occlusion. The authors recommended wearing only glasses without occlusion or surgery and he recovered fusion. Three months later, orthophoria was maintained at distant target, with 8PD esophoria at near target with glasses. Although this complication should be considered before occlusion therapy, it must be taken continuously if needed, because an increase of the deviation size with occlusion may simply reflect a true deviation and may not be a poor prognostic sign.
*Accommodation, Ocular ; Amblyopia/physiopathology/therapy ; Child ; Esotropia/*etiology/physiopathology ; Eyeglasses ; Female ; Humans ; Male ; *Sensory Deprivation

We studied on change of lens accommodation and pupil light reflex caused by VDT work in six women and compared them with those of other office works. The results were as follows. 1. In VDT work group, the accommodation contraction velocity decreased during the first 2-hr VDT task, then recovered markedly by the end of the one-hour lunch break, and then decreased again by the end of the 2nd 2-hr VDT task. Changes of relaxation velocity showed similar pattern although it was less typical than that of contraction velocity. 2. There was no marked change in accommodation contraction velocity and amplitude of accommodation in general office work group and near-distance office work group, and in the near-distance office work accommodation relaxation velocity decreased according to work load without recovery after lunch break. 3. Initial pupil diameter, initial pupil area of light reflex decreased significantly during VDT task only in VDT work group, and didn't recover after lunch break. These results suggest possibility that changes of accommodation contraction velocity, accommodation relaxation velocity, near point distance, and pupil diameter and area are useful in evaluating characteristics of VDT work. For this, more research adjusted individual differences, circadian rhythm, emotional stress needs.
Accommodation, Ocular ; Circadian Rhythm ; Female ; Humans ; Individuality ; Lunch ; Pupil* ; Reflex* ; Relaxation ; Stress, Psychological

OBJECTIVE: To evaluate the change in accommodative lag and accommodation convergence/accommodation (AC/A) after patients with myopia wear orthokeratology lenses. 
 METHODS: A total of 48 myopic subjects (a test group), who wore orthokeratology lenses regularly, and 48 myopic subjects (a control group), who wore spectacles regularly, were enrolled for this study from January 2011 to January 2013 in Optometric Center, the Forth Hospital of Changsha. Accommodative lag was measured by fused cross cylinder method, where the patients should gaze at the front optotypes 40 cm away. Gradient of the AC/A ratio was measured by Von Grafe method to check closer distance heterophoria. Accommodative lag and AC/A ratio were analyzed by statistics.
 RESULTS: After 1-year follow-up, accommodative lag and AC/A rate in patients with low or moderate myopia in the test group was decreased in 1, 3, 6 months or 1 year compared with that in the control group (P<0.05). 
 CONCLUSION Compared with spectacles, orthokeratology lenses are able to decrease accommodative lag and high AC/A rate in patients with low or moderate myopia. The relationship between accommodation and convergence is improved by orthokeratology lenses. Orthokeratology is an effective way to control myopia.
Accommodation, Ocular ; Case-Control Studies ; Contact Lenses ; Eyeglasses ; Humans ; Myopia ; therapy ; Orthokeratologic Procedures ; Strabismus

OBJECTIVE: To measure and compare the accommodative amplitude of Filipino patients with different accommodative conditions using a wavefront aberrometer.

METHODS: A total of 120 eyes of 67 patients seen in a private eye center were included and divided into two groups (phakic and pseudophakic). After undergoing routine ophthalmologic examination that included manifest refraction and visual acuity testing, accomodative amplitude was measured using the iTraceTM wavefront aberrometer. Comparison of the measurements was made between the accommodative amplitude of phakic pre-presbyopes and presbyopes, and between eyes implanted with monofocal and accommodating intraocular lenses (IOLs).

RESULTS: The mean age of the pre-presbyopes was 27 years, presbyopes 50 years, monofocal IOL 69 years and accommodating IOL 67 years. The mean accommodative amplitude of the pre-presbyopes was 1.64 ± 1.06D, presbyopes 0.99 ± 0.42D, monofocal IOL 0.36 ± 1.16D, and accommodating IOL 0.94 ± 0.89D. The pre-presbyopes had a higher accommodative amplitude than the presbyopes (p=0.008), while the accommodating IOL subgroup had a higher amplitude than the monofocal IOL subgroup (p=0.02). Increasing age was correlated with decreasing amplitude in the phakic group (r2=0.926). There was no correlation between refractive error and amplitude of accommodation in the phakic and pseudophakic groups (r2=0.02 for both groups).

CONCLUSION: The wavefront aberrometer is a reliable tool in objectively measuring accommodative amplitude. Pre-presbyopes and accommodating IOLs were shown to have higher amplitudes of accommodation than presbyopes and monofocal IOLs.

Human ; Male ; Female ; Adult ; Lenses, Intraocular ; Accommodation, Ocular ; Presbyopia ; Visual Acuity ; Refractive Errors

A vernier optometer, based on the Scheiner principle, that makes use of polarized light, is designed and developed. It is specialized in measurement of tonic accommodation, accommodation and accommodation response. The vernier optometer has been proved by chinical testing results, to be a reliable and effective instrument with fine stabilily, good repeatability and sensitivity for short sight study relating to oculogyral parameters.
Accommodation, Ocular ; Adult ; Diagnostic Techniques, Ophthalmological ; instrumentation ; Equipment Design ; Humans ; Myopia ; diagnosis ; Optometry ; instrumentation ; Refraction, Ocular ; Reproducibility of Results ; Visual Acuity