JBO - Volume 22 - Issue 5 - Real-Time Objective Measurement of Accommodation While Reading

Journal: 
Author: 
Kundart, James, OD, MEd
Tai, Yu-Chi, PhD
Hayes, John R, PhD
Gietzen, Joshua, BS
Sheedy, James, OD, PhD
Title: 
Real-Time Objective Measurement of Accommodation While Reading
Abstract: 

Purpose: In the clinical care of functional vision disorders, dynamic retinoscopy such as Monocular Estimate Method has been the mainstay for objective measurement of the accommodative response. It is valuable, fast and widely available. Dynamic retinoscopy however does not allow for quantified measures of accommodation by inexperienced clinicians or technicians. Automated, objective methods for performing simple clinical tests like book retinoscopy would be most useful, if only real-world targets like continuous text could be included. This study was aimed at determining the feasibility of collecting automated, continuous accommodative data during reading.

Methods: Real-time accommodative measurements were measured on nine subjects under three conditions while accommodative measurements were collected at 5Hz with the Grand Seiko WAM-5500 open-field autorefractor. The first two conditions tested the ability of the autorefractor to measure accommodative response using peripheral gaze: with distant and near targets. The third condition involved reading from the electronically presented text. Results: Accommodative response, allowing for expected accommodative lag, was measured within 0.25 D of expected clinical values during reading in a 3-line vertical, 15-degree horizontal window.

Conclusions: Within the 15º visual angle range, open-field autorefraction is able to accurately measure the realtime accommodative response to within 0.25 D. Although there are dynamic fluctuations in the accommodative response during reading, measured accommodative lag increases with demand and is consistent with the literature on dynamic retinoscopy. Open-field autorefraction has the potential to demonstrate accommodative dysfunction when used in real-time mode.

JBO - Volume 21 - Issue 5 - Computer Vision Syndrome: Accommodative & Vergence Facility

Journal: 
Author: 
Rosenfield, Mark
Gurevich, Regina
Wickware, Elizabeth
Lay, Marc
Title: 
Computer Vision Syndrome: Accommodative & Vergence Facility
Abstract: 

Computer vision syndrome (CVS) is a complex of symptoms experienced by up to 90% of computer users. Questions remain regarding its etiology. Changes in accommodation or vergence have been suggested as causative factors. This study sought to determine if subjects with CVS had abnormal accommodative or vergence facility findings and to identify if sustained computer use produces a change in these parameters. Twenty two subjects read text from a computer screen for a continuous 25 min period. Vergence facility and both monocular and binocular accommodative facility were measured. Following the computer task, subjects completed a questionnaire regarding their level of discomfort during the task. No significant change in monocular accommodative or vergence facility was observed following the computer task, although a small increase in post-task binocular accommodative facility was noted. The highest ocular symptoms reported were tired eyes, eyestrain and dry eye. These were not correlated significantly with the accommodative or vergence facility findings.The symptoms reported appeared to be related to dry eye, and not to either accommodative or vergence abnormalities.

JBO - Volume 21 - Issue 4 - The Accommodative Performance of Infants & Young Children

Journal: 
Author: 
Candy, Rowan T.
Title: 
The Accommodative Performance of Infants & Young Children
Abstract: 

Abnormal visual experience has been shown to lead to abnormal visual development.  Abnormal visual experience in clinical terms is typically defined based on retinal image quality or retinal image correspondence. In addition to refractive error, retinal image quality depends on the accommodative performance of the patient. This review discusses studies of the development of accommodation in infants
and their implications for the clinical assessment of young patients.

JBO - Volume 20 - Issue 5 - Prospective Data from a Randomized Longitudinal Stury of Accommodation & Convergence Training as a Potential Method of Myopia Control in Children

Journal: 
Author: 
Goss, D.A.
Rainey, B.B.
Title: 
Prospective Data from a Randomized Longitudinal Stury of Accommodation & Convergence Training as a Potential Method of Myopia Control in Children
Abstract: 

Contemporary theories of myopia etiology incorporate nearwork and aspects of visual function at nearpoint. This paper reports the results of a small prospective longitudinal study of accommodation and vergence training as a method of myopia control. Twenty-one subjects were randomized into the control group and 22 subjects into the training group, but only 10 trainees completed the three years of the study. Both control group subjects and training subjects wore single vision spectacle lenses equal in power to the subjective refraction. Training subjects performed standard home procedures to improve accommodation and vergence function. Rates of myopia progression were calculated by dividing the change in autorefraction spherical equivalent by time in the study. Nott dynamic retinoscopy was performed at the annual examinations with a 40 cm test distance and the subject viewing through a +1.00D add, the subjective refraction, and a -1.00D add. There was a high drop-out rate in the vision training group, undoubtedly due to the time commitment. The rates of myopia progression were not significantly different between the control group and the training group. The regimen of accommodation and convergence training used in this study did not reduce the rate of childhood myopia progression. Studies using individualized vision therapy programs or using vision therapy programs designed to treat specific anomalies of the vision system related to myopia progression may have more positive results.

JBO - Volume 20 - Issue 5 - Control of Myopia with Nearpoint Plus as a Function of Near Phoria - Literature Review & Additional Prospective Data

Journal: 
Author: 
Goss, D.A.
Rainey, B.B
Title: 
Control of Myopia with Nearpoint Plus as a Function of Near Phoria - Literature Review & Additional Prospective Data
Abstract: 

Studies which have examined the effect of bifocals or progressive addition lenses on the progression of myopia in children with different nearpoint phoria levels are reviewed. There is limited effect on myopia progression in children with exophoria or orthophoria. For children with esophoria, the number of subjects in various studies were often too small to achieve statistical significance. However, a reduction in the rate of progression with plus adds in esophoria can be recognized by comparing the results of multiple studies. A small previously unpublished prospective study, where rates of myopia progression is also presented. This study found that the difference in mean rates for esophoric plus add wearers who had their nearpoint phoria shifted out of esophoria with the add (-0.32D/yr) and single vision lens group subjects with esophoria at near (-0.49D/yr) was almost statistically significant (p=0.052). Implications of the literature reviewed and of the additional prospective data are discussed. Reduction in progression rates may be more likely in nearpoint esophoria when the phoria is shifted into exophoria with the add. Future studies to control myopia with plus adds should consider the use of individually prescribed add powers rather than providing all plus add group subjects with the same add power.

JBO - Volume 20 - Issue 3 - Effect of Retinal Defocus on Rapid Serial Visual Presentation (RSVP) Digit Recognition

Journal: 
Author: 
Xu, J.J.
Ciuffreda, K.J.
Chen, H.
Fan, L.
Title: 
Effect of Retinal Defocus on Rapid Serial Visual Presentation (RSVP) Digit Recognition
Abstract: 

Nearly all objects in one’s visual field are defocused to some extent, and its potentially deleterious effect on visual task performance is variable. The purpose of the present study was to assess the effect of retinal defocus on rapid serial visual presentation (RSVP) single digit recognition. Subjects were 17 myopic and two emmetropic, visually-normal, young adults. Single digit, random Arabic numbers (1-9; 40 total at each level) were presented on a computer screen using an RSVP paradigm under binocular viewing conditions. Full refractive corrections at 4m and 40cm were in place. Target contrast was 50% with 20/50 font size. Defocus lenses were introduced in descending order: +2.5, 2.0, 1.5, 1.0, 0.5D, and plano. Maximum digit recognition per minute was determined under each lens condition using a modified staircase technique. There was a rapid, linear decrease in digit recognition rate with increase in retinal defocus. The effect was greater at distance than at near. Digit recognition speed was highly susceptible to retinal defocus, perhaps due to the dynamic nature of the stimulus. The results have implications related to everyday tasks in a complex and constantly changing dynamic visual environment, such as during driving and sports.

JBO - Volume 19 - Issue 2 - Effect of the EYEPORT System on Visual Function in ADHD Children - A Pilot Study

Journal: 
Author: 
Hagen, H.
Moore, K.
Wickham, G.
Maples, W.C
Title: 
Effect of the EYEPORT System on Visual Function in ADHD Children - A Pilot Study
Abstract: 

The diagnosis of ADHD is a complex procedure that includes a subjective evaluation of a person’s behavior by parents, teachers and physicians. Many auditory, behavioral and vision conditions can mimic ADHD. Visual function clearly impacts attention, particularly during near point activities such as reading. This study investigated if a type of therapy (EYEPORT®) would significantly improve attention. This system was the sole vision therapy (VT) instrument used in this study. The Test of Variables of Attention (TOVA®) was used to objectively measure visual attention. ADHD-diagnosed subjects were divided into two groups by age. All subjects were examined at baseline, mid-study and completion of therapy, with the TOVA® and with optometric tests. The 1st group underwent VT for four weeks while the 2nd group did not receive VT. After four weeks, (mid-study) the 2nd group received VT and the 1st did not. Serious compliance problems were encountered. Significant improvements in the amplitude of accommodation and stereoacuity were found with those that completed the study. The TOVA® variables, commission errors and response time also significantly improved. EYEPORT® therapy administered over a short period of time significantly improved some visual skills and measures of attention. This pilot study indicated that a more elaborate study should be undertaken to further investigate if VT would show improvement in visual attention of ADHD-diagnosed subjects.

JBO - Volume 18 - Issue 6 - Optometric Vision Therapy in the Management of Consecutive Intermittent Exotropia with Dissociated Vertical Deviation and Anomalous Correspondence - A Case Study

Journal: 
Author: 
Chorn, B.
Steiner, A.
Title: 
Optometric Vision Therapy in the Management of Consecutive Intermittent Exotropia with Dissociated Vertical Deviation and Anomalous Correspondence - A Case Study
Abstract: 

Consecutive exotropia refers to a manifest exodeviation following surgery to correct esotropia. Surgery is common for early onset esotropia, particularly congenital/infantile esotropia. Congenital/infantile esotropia is usually accompanied by several ocular phenomena, including: latent nystagmus, dissociated vertical deviation (DVD) and overaction of the extraocular muscles, especially the inferior obliques. Additionally, since there is a disturbance in normal binocular vision, anomalous correspondence (AC) is often present. Despite this poor or limited binocularity, interventions to increase fusional ability are possible and should be considered.

JBO - Volume 18 - Issue 4 - Computerized Vision Therapy for Home and Office Treatment of Accommodative & Vergence Disorders, & Amblyopia

Journal: 
Author: 
Cooper, J.
Title: 
Computerized Vision Therapy for Home and Office Treatment of Accommodative & Vergence Disorders, & Amblyopia
Abstract: 

Vision therapy or orthoptics is the standard treatment for symptomatic accommodative-vergence anomalies and amblyopia. Computerization of vision therapy has improved treatment results by: standardizing protocols; providing positive or negative reinforcement based upon responses; eliminating experimental (therapist) bias in research and/or therapy; and standardizing stimuli and methodology for diagnosis/treatment. This paper reviews the literature regarding the efficacy of the automated treatment of accommodative vergence anomalies, and amblyopia. The use of the Computer Orthopter, its home based program, HTS and amblyopia programs are discussed in detail.

JBO - Volume 18 - Issue 3 - Military Optometry In the Care of Traumatic Brain Injury Patients

Journal: 
Author: 
VanRoekel, R.
Title: 
Military Optometry In the Care of Traumatic Brain Injury Patients
Abstract: 

The medical care system for soldiers and Marines who incur traumatic brain injury in Iraq and Afghanistan is presented. After initial immediate care is provided, they are sent to a staging area for further treatment and then to a tertiary care hospital in Germany. Finally, they are assigned to an army or navy medical care facility in the United States. All suspected traumatic brain injured patients are screened to determine the level of severity of injury. They are then assigned to either an Army Hospital, or a Department of Veterans Affairs health care facility for further treatment and rehabilitation. The author notes his impressions that in terms of vision, there are often changes in refraction, impaired accommodation and binocular functioning.