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.

The accommodative function before and after laser in situ keratomileusis (LASIK) was observed, and the effect of LASIk on accommodation was investigated. In a prospective clinical trial, 48 myopic patients (96 eyes) subject to bilateral LASIK in Refractive Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology (China) from March 2006 to June 2006 were selected and studied. Refractions, accommodative range, amplitude of accommodative response and high frequency component (HFC) of accommodative microfluctuations were measured with NEDIK-730A before and one week and 30 days after operation. Dominant and non-dominant eyes were determined by hole-in-card method. It was found that all of the operative eyes showed an uncorrected visual acuity of 0.8 or better one week postoperatively, and 1.0 or better 30 days postoperatively. Compared with those preoperatively, accommodative range and HFC had no significant difference at first week and 30th day after operation in both dominant eyes and non-dominant eyes (P>0.05), but there was a significant difference in the amplitude of accommodative response/accommodative stimulus ratio (A/S) after operation (P<0.01), and no significant difference was found in accommodation between one week and 30 days postoperation. No ocular dominance's change was noted. There was no significant difference in accommodative function between dominant eyes and non-dominant eyes. It was suggested that LASIK produced no significant effect on accommodation.
Accommodation, Ocular/*physiology ; Keratomileusis, Laser In Situ/*adverse effects ; Myopia/*physiopathology ; Myopia/*surgery ; Postoperative Period ; Prospective Studies ; Young Adult

PURPOSE: To investigate the effect of watching 3-dimensional (3D) television (TV) on refractive error in children. METHODS: Sixty healthy volunteers, aged 6 to 12 years, without any ocular abnormalities other than refractive error were recruited for this study. They watched 3D TV for 50 minutes at a viewing distance of 2.8 meters. The image disparity of the 3D contents was from -1 to 1 degree. Refractive errors were measured both before and immediately after watching TV and were rechecked after a 10-minute rest period. The refractive errors before and after watching TV were compared. The amount of refractive change was also compared between myopes and controls. The refractive error of the participants who showed a myopic shift immediately after watching TV were compared across each time point to assure that the myopic shift persisted after a 10-minute rest. RESULTS: The mean age of the participants was 9.23 ± 1.75 years. The baseline manifest refractive error was -1.70 ± 1.79 (-5.50 to +1.25) diopters. The refractive errors immediately after watching and after a 10-minute rest were -1.75 ± 1.85 and -1.69 ± 1.80 diopters, respectively, which were not different from the baseline values. Myopic participants (34 participants), whose spherical equivalent was worse than -0.75 diopters, also did not show any significant refractive change after watching 3D TV. A myopic shift was observed in 31 participants with a mean score of 0.29 ± 0.23 diopters, which resolved after a 10-minute rest. CONCLUSIONS: Watching properly made 3D content on a 3D TV for 50 minutes with a 10-minute intermission at more than 2.8 meters of viewing distance did not affect the refractive error of children.
Accommodation, Ocular/*physiology ; Child ; Depth Perception/*physiology ; Disease Progression ; Female ; Humans ; Imaging, Three-Dimensional/*adverse effects ; Male ; Refractive Errors/*physiopathology ; *Television ; Vision, Binocular/*physiology

PURPOSE: The aim of this study is to investigate the clinical characteristics of patients diagnosed with refractive accommodative esotropia (RAE) whose refractive errors were gradually reduced to below +2.00 diopters (D) during follow-up but use of spectacles was still required for maintenance of good ocular alignment. METHODS: We conducted a retrospective review of the medical records of patients diagnosed with RAE from 1995 to 2011. Patients were divided into 2 groups according to their ocular alignment at the last visit. Inclusion criteria were hyperopia > or =+2.00 D detected with cycloplegic refraction at the initial visit, which then became mild hyperopia (<+2.00 D) or myopia during follow-up, with more than 5 years of follow-up. RESULTS: A total of 92 patients met the inclusion criteria. Twenty-six patients showed persistent esotropia (> or =10 prism diopters [PD]) without spectacles (group A) and 66 patients showed good ocular alignment (<10 PD) without spectacles (group B) at the last visit. No statistically significant differences in the spherical equivalent of the refractive errors at the initial and last visit were observed between the two groups. A significantly lower number of positive responses on the Lang I stereotest was observed in group A (n = 1, 3.8%) compared to group B (n = 22, 33.3%) (p = 0.003). There were increasing trends toward group A with worsening stereoacuity measured by the Stereo Fly Stereotest between the two groups (p = 0.016, linear by linear association). The results of the Lang I test, Stereo Fly Stereotest, and duration between the onset of esotropia and prescribing spectacles showed a significant association with the discontinuation of spectacles in the univariate logistic analysis. CONCLUSIONS: Stereoacuity showed more significant associations than refractive errors in RAE with refractive error <+2.00 D but still required spectacles for maintenance of good ocular alignment. The prompt treatment of accommodative esotropia at the onset of esotropia is important for the discontinuation of spectacles.
Accommodation, Ocular/physiology ; Adult ; Aged ; Esotropia/*physiopathology ; *Eyeglasses ; Female ; Follow-Up Studies ; Humans ; Hyperopia/physiopathology/*therapy ; Male ; Middle Aged ; Refraction, Ocular/physiology ; Retrospective Studies ; Vision, Binocular/*physiology ; Visual Acuity/physiology

PURPOSE: To compare the clinical outcome of AT-45 implantation between high myopic eyes and non-high myopic eyes. METHODS: Retrospective, non-randomized, comparative trial. The medical charts of 28 patients with 35 eyes who had phacoemulsification and AT-45 implantation were retrospectively reviewed. 13 eyes of 10 patients were included in the high myopic group (axial length > or = 26.0 mm) and 22 eyes of 18 patients were included in the non-high myopic group. The clinical data included unilateral best-corrected visual acuity (BCVA) and distance-corrected near visual acuity (DCNVA) at 6 months follow-up after the surgery. The results were compared between the two groups. RESULTS: In the non-high myopic group, 22 eyes (100%) and 19 eyes (86.4%) achieved a BCVA of 20/25 and 20/20 or better respectively. For the high myopic group, the results were 13 eyes (100%) and 12 eyes (92.3%) respectively, at 6 months after the surgery. In the non-high myopic group, 21 (95.4%) and 7 eyes (31.8%) achieved a DCNVA of 20/40 and 20/25 or better. For the high myopic group, the results were 13 (100%) and 4 eyes (30.8%) respectively, at 6 months after the surgery, the differences between the two groups for a BCVA of 20/25 or better and 20/20 or better and a DCNVA 20/40 or better and 20/25 or better were not statistically significant. CONCLUSIONS: Six months clinical outcome of cataract surgery with an AT-45 for the high myopic eyes was satisfactory; it was not significantly different from that of the non-high myopic eyes.
*Accommodation, Ocular ; Adult ; Aged ; Female ; Humans ; *Lens Implantation, Intraocular ; *Lenses, Intraocular ; Male ; Middle Aged ; Myopia, Degenerative/*surgery ; Phacoemulsification ; Retrospective Studies ; Visual Acuity/physiology

PURPOSE: To report the long term results of bifocal treatment in nonrefractive accommodative esotropia and to analyze the changes of accommodative convergence to accommodation (AC/A) ratio. METHODS: Sixteen patients treated with bifocal glasses for at least 5 years were evaluated retrospectively. Angle of deviation at near and distance, refractive error, and AC/A ratio by the lens gradient method were analyzed. The changes of AC/A ratios were also compared after dividing the patients according to continuation or cessation of bifocal therapy. RESULTS: Six patients (38%; bifocal stop group, BSG) were able to stop using bifocal glasses at an average age of 10.8 years (range, 6.5 to 15.4 years) during their follow-up. However, the other ten patients (62%; bifocal continue group, BCG) had to continue using bifocal glasses until the final visit, which was 13.8 years on average (range, 11.3 to 18.5 years). The AC/A ratio decreased from time of bifocal prescription to the last visit in both groups, from 4.4 to 2.7 in the BSG and from 5.9 to 4.5 in the BCG. AC/A ratios were significantly higher (p = 0.03) in the BCG than that of the BSG from the beginning of bifocal treatment and this difference was persistent until the final visit (p = 0.03). CONCLUSIONS: The AC/A ratio decreased with age in both groups but was significantly higher throughout the entire follow-up period in the BCG. AC/A ratio at bifocal prescription could be an important factor in predicting response to bifocal treatment.
Accommodation, Ocular/*physiology ; Adolescent ; Child ; Cyclopentolate/administration & dosage ; Esotropia/*physiopathology/*therapy ; *Eyeglasses ; Female ; Humans ; Male ; Phenylephrine/administration & dosage ; Retrospective Studies ; Statistics, Nonparametric ; Tropicamide/administration & dosage

PURPOSE: In this study, we examined the stability of the lens-angle supporter (LAS) for accommodation restoration by comparing intraocular lens (IOL) location, after-cataract and ciliary body damage after cataract surgery in rabbits. METHODS: Eight rabbits were divided into experimental and control groups of four rabbits each. Phacoemulsification and irrigation and aspiration were performed in all rabbits. This was followed by an LAS and IOL insertion in the four experimental rabbits. In the four control rabbits, only an IOL insertion was performed. Six months after the surgery, the location of the IOL, the conditions of the lens capsule and ciliary body were evaluated using a slitl-amp examination and Miyake-Apple view. RESULTS: For the experimental group, the ultrasound biomicroscope results showed normal LAS and IOL positioning in all four cases. According to the slitlamp examination and Miyake-Apple view, the IOL was positioned at the center, with less after-cataract and damage to the ciliary body. For the control group, ultrasound biomicroscope results indicated a higher IOL position than normal, as well as a single case of IOL decentering. According to the slit-lamp examination and Miyake-Apple view, the IOL was decentered with more severe after-cataract and ciliary body damage. CONCLUSIONS: The LAS has the potential to maintain a stable IOL position while producing less after-cataract when used in lens-angle reconstruction for correction of presbyopia. Moreover, LAS implantation incurs less damage to the ciliary body.
Accommodation, Ocular/physiology ; Animals ; Anterior Eye Segment ; Ciliary Body/injuries ; Disease Models, Animal ; Eye Injuries/*surgery ; Lens Capsule, Crystalline/*surgery ; *Lens Implantation, Intraocular ; Microscopy, Acoustic ; *Phacoemulsification ; Rabbits ; *Reconstructive Surgical Procedures