Kelly A. Frantz

Nearpoint of convergence: test procedure, target selection, and normative data.

Background. The purpose of this study was to help determine the most appropriate target to be used for the assessment of the nearpoint of convergence, normative data for the break and recovery in adults, and the diagnostic value of the red-glass modification and repetition of the nearpoint of convergence. Methods. A total of 175 subjects with normal binocular vision and 38 subjects with convergence insufficiency were evaluated. The nearpoint of convergence was measured three ways, with an accommodative target, a penlight, and a penlight with red and green glasses. The nearpoint of convergence was also measured using a penlight for 10 repetitions. Results. Results suggest a clinical cutoff value of 5 cm for the nearpoint of convergence break and 7 cm for the nearpoint of convergence recovery with either an accommodative target or a penlight with red and green glasses. Conclusion. This study establishes normative data for the nearpoint of convergence break and recovery in the adult population and supports the value of various test modifications when other testing is equivocal.

Normative study of accommodative facility in elementary schoolchildren.

ABSTRACT Although accommodative facility testing is used widely in the evaluation of accommodation in children, published normative data are not available for this age group. Current values being used are based upon studies of adult populations. In order to establish norms, 542 elementary schoolchildren were screened. Those that passed a specific set of criteria were included in the accommodative facility assessment. We used a new target and instructional set, which took into consideration the problems associated with subjective testing of young children. The results revealed lower mean accommodative facility values for both monocular and binocular accommodative facility than the values obtained previously from adult populations. These new findings can be used as a clinical guide to evaluate accommodative facility in young children.

Efficacy of a mydriatic spray in the pediatric population

Background. Children often resist instillation of mydriatic drops for dilated fundus evaluation. As cycloplegic sprays have proven useful, this studys aim was to demonstrate efficacy of a mydriatic spray. Methods. Twenty-two healthy subjects, ages 2 to 8 years, participated in the study. All but two had dark brown irides. Subjects were given either one drop each of 1% tropicamide and 2.5% phenylephrine in each eye or one application of mydriatic spray (containing concentrations of 0.5% tropicamide and 2.5% phenylephrine) to each closed eyelid. Pupils were measured with a pupil gauge before drug delivery and every 10 min thereafter, for 40 min. Results. Repeated measures analysis of variance for the five time intervals demonstrated no significant difference between the two application methods nor in the method/time interaction, but a statistically significant increase in pupil size over time (p<0.0005) for each method. A t-test revealed no statistically significant difference in pupil size (p>0.05) between the two methods of drug administration at 40 min after application. Conclusions. This study suggests that use of mydriatic sprays on closed eyelids is as efficacious as use of mydriatic drops in open eyes for children.

Comparison of disparometer fixation disparity curves as measured with and without the phoropter.

Traditionally, Disparometer fixation disparity curve (FDC) measurement has been performed using a phoropter, although more recently some clinicians have suggested that the Disparometer be used outside the phoropter. Whereas vertical fixation disparity (FD) measurements have been found to correlate well when obtained with and without a phoropter, there is currently no evidence that horizontal FDCs are similar in the two testing situations. A FDC was plotted for 30 visually asymptomatic young adults both in and out of the phoropter. Statistical analysis revealed no significant differences between results on the basis of curve type, slope, y- or x-intercept; however, noteworthy individual variations did occur. Therefore, we conclude that consistency of testing method is important when serial curves are plotted for a given patient. Although each method has some advantages and disadvantages, neither is clearly superior based on this study.

Effect of Amblyopia Treatment on Macular Thickness in Eyes With Myopic Anisometropic Amblyopia.

PURPOSE To determine whether abnormal macular thickness in myopic anisometropic amblyopia differed after amblyopia treatment. Furthermore, to investigate whether effect of treatment on macular thickness was associated with subject age or improvement in stereoacuity. METHODS Seventeen children (mean age: 9.0 [±3.0] years, ranging from 5.7-13.9 years) with myopic anisometropic amblyopia (visual acuity [VA] in amblyopic eyes: 20/80-20/400) were recruited and treated with 16-week refractive correction, followed by an additional 16-week refractive correction and patching. Macular thickness, best-corrected VA, and stereoacuity were measured both before and after amblyopia treatment. Factorial repeated-measures analysis of variance was performed to determine whether macular thickness in amblyopic eyes changed after amblyopia treatment. RESULTS Mean baseline VA in the amblyopic eye was 1.0 ± 0.3 logMAR and improved to 0.7 ± 0.3 after amblyopia treatment (P < 0.0001). The interaction between eye and amblyopia treatment was statistically significant for average foveal thickness (P = 0.040). There was no treatment effect on fellow eyes (P = 0.245); however, the average foveal thickness in the amblyopic eye was significantly reduced after amblyopia treatment (P = 0.049). No statistically significant interactions were found for the other macular thickness parameters (P > 0.05). CONCLUSIONS Abnormal central macula associated with myopic anisometropic amblyopia tended to be thinner following amblyopia treatment with no significant changes in peripheral macular thickness.

Value of the Heidelberg Retinal Tomograph in optic nerve hypoplasia.

Purpose. A case of optic nerve hypoplasia (ONH) is reported to demonstrate the value of the Heidelberg Retinal Tomograph II (HRT) in assisting with the diagnosis. Case Report. An 8-year-old black male was referred to our clinic for evaluation of right esotropia and presumed amblyopia. Best-corrected visual acuities were 20/60− OD (right eye) and 20/25+1 OS (left eye). Cover test showed constant right esotropia, measuring 10&Dgr; at distance and 16&Dgr; at near. A smaller optic nerve head was detected OD with absence of the double ring sign. The findings of HRT were consistent with a diagnosis of unilateral ONH, with a disc area of 1.545 mm2 OD vs. 2.527 mm2 OS. Discussion. The clinical features, management, and associations of ONH are discussed. Conclusion. HRT is a useful tool to assist in diagnosis of ONH by physically measuring the optic nerve.

A prospective study of different test targets for the near point of convergence

Purpose:  To determine whether different test targets including an accommodative target (AT), a transilluminator (TR), and a transilluminator with a red lens (RL), affect the near point of convergence (NPC) value; and to determine which test target is most sensitive to identify convergence insufficiency (CI) in young adults.

Re-evaluation of the Four Prism Diopter Base-out Test

The four prism diopter base-out (4Δ BO) test is often recommended for use as an objective assessment of binocular visual function in patients with suspected microstrabismus or central suppression; however, many aspects of the test are unknown. In this series of investigations we evaluated: (1) inter-observer agreement between 2 examiners, using 15 subjects; (2) types of eye movements made and prevalence of the various response types demonstrated in 212 children and 116 adults with normal binocular vision, and 10 children and 4 adults with abnormal binocular vision; and (3) repeatability of test results for 22 subjects evaluated on two separate occasions. In addition, using an SRI Eyetracker, we documented the eye movements made while testing 2 subjects with small angle strabismus and 4 subjects with normal binocular vision. We found the following results: (1) inter-observer agreement is high; (2) both children and adults exhibit many atypical responses, whether or not they have normal binocular vision; (3) diplopia awareness does not differentiate between subjects with normal and abnormal binocular vision; and (4) 4Δ BO test results are not repeatable. Due to frequent atypical and variable responses in subjects with or without normal binocular vision, we suggest the examiner use caution when making a diagnosis based solely on the 4Δ BO test.

Vision therapy management for dissociated horizontal deviation.

Purpose Dissociated horizontal deviation (DHD), a rare subtype of strabismus, is a change in horizontal eye alignment that does not obey Hering’s law. The variation is unrelated to a change in accommodation and depends on which eye is fixating. Both esotropia (ET) and exotropia (XT) can manifest in the same patient with DHD. Surgery has been reported to manage DHD, but often a second or third surgery is necessary. We report two cases of DHD that were managed with vision therapy (VT). Case Reports Case one: A 9-year-old girl presented for eye examination with her parents noting an eye drifting out. Cover test showed a DHD that varied from 15&Dgr; left ET to 15&Dgr; alternating XT. A 40&Dgr; XT manifested when she was inattentive. Anti-suppression, vergence, accommodation, and oculomotility were addressed with VT. Upon completion of VT, binocular vision functions were normal except for appreciation of global stereopsis. No strabismus was observed during the examination. These findings were stable at a 7-month follow-up visit. Case two: A 40-year-old man presented for eye examination with the complaint of double vision and eye strain. Cover test revealed a DHD that varied from 5&Dgr; ET to 15&Dgr; XT, along with DVD. A 30 to 40&Dgr; XT was observed during visual inattention. Antisuppression and vergence skills were addressed with VT. At the end of VT, most binocular vision functions were normal. No strabismus was observed on cover test. Follow-up examination 16 years later showed no strabismus by cover test, although XT manifested when he was inattentive. Conclusions In two DHD cases, control of eye alignment improved with VT. To the best of our knowledge, these are the first case reports to describe management of DHD with VT. Eye care practitioners should be aware that a long period of VT may be necessary to successfully manage DHD.

Comparison of Heidelberg Retina Tomograph with disc-macula distance to disc diameter ratio in diagnosing optic nerve hypoplasia.

To evaluate whether Heidelberg Retinal Tomograph (HRT) is a valid test for diagnosing congenital optic nerve hypoplasia (CONH) compared to the ratio of the distance between the centre of the optic disc and the centre of the macula and the mean optic disc diameter (DM:DD ratio). Furthermore, to determine the optimal cut‐off value of HRT disc area to differentiate a hypoplastic disc from a normal optic disc.