Purpose: The factors associated with the increased risk of glaucoma include intraocular pressure (IoP), central corneal thickness (CCT), vertical cup-to-disc ratio, visual field index, age, and diabetes mellitus. We have investigated the relation of IoP with CCT in normal, healthy pre-presbyopic persons. Methods: A total population of 698 normal patients (1396 eyes), aged 4 to 40 years, were evaluated in two separate clinics, one in Houston, Texas, USA and the second in oakville, ontario, Canada. IoP was measured using a noncontact tonometry (nCT 20 Topcon). In Houston, CCT was determined by using the Pentacam (occulus Pentacam – Belinea) and an optical pachymetry that utilized optical low-coherence reflectometry (oLCR) technology, and in oakville, a Hagg-Streit slit lamp–mounted pachymeter was used. Results: of the total number of eyes tested, 1226 eyes had IoP of 21 millimetres of mercury (mm Hg) or lower and 134 eyes had IoP greater than 21 mm Hg. For the normal IoP group (n = 1226 eyes), the overall IoP mean was 15.63 +/– 2.87 mm Hg; the overall CCT mean was 550.21 +/– 39.64 micrometres (µm). In the normal IoP group, for every 10 µm change in CCT, IoP changed a statistically significant amount of 2.49 mm Hg (p <0.05 to <0.001), except for the 10 nm CCT bins above and below the 550 µm mean. Conclusions: Although many investigators have described a positive correlation between IoP and CCT, this relationship has not been demonstrated in normal, healthy pre-presbyopic persons. There is a significant change of IoP with CCT (2.49 mm Hg IoP change per 100 µm of CCT). These normative data allow primary eye care clinicians to accurately determine normal and abnormal IoP and refine the index of suspicion for identifying patients who need to be worked up for glaucoma.

Introduction: Glaucoma, which is often accompanied by elevated intraocular pressure (IOP), causes progressive optic nerve atrophy and blindness. Among ocular structure parameters abnormalities in central corneal thickness (CCT), cup-to-disc (C/D) ratio, inter-eye C/D ratio asymmetry, optic disc area, and neuro-retinal rim area (N-RRA) appear to be highly correlated with glaucoma. We compare these specific ocular structures in a group of young normal pre-presbyopic patients and in a group of patients being treated for glaucoma. Methods: After written informed consent, 1433 consecutive normal, and 56 consecutive patients being treated for glaucoma were assessed by including age, race, sex, IOP (NCT), C/D ratio, optic disc area, N-RRA (Optos), central center thickness (CCT), and anterior chamber depth. Results: Combinations of findings in CCT, C/D ratio, C/D ratio asymmetry, disc area, and N-RRA (assessed by Z-score) were present in 65.52% of patients being treated for glaucoma and 22.96% of young normal patients. For young normal patients, overall average CCT was 550.37+/-39.47µm. Overall average C/D ratio was 0.39+/-0.11. Inter-eye C/D asymmetry was 0.02+/-0.06. Overall average disc area was 2.46+/-0.49mm2 (7863.54+/1630.42 pixels). Overall average N-RRA was 1.44+/-0.35mm2 (4785.88+/1161.14 pixels). C/D ratio increased modestly with disc area increase, an increase not associated with thinning N-RRA. Thin N-RRA was associated with small optic discs that had large C/D (t=-8.21, p=0.000, DF=93). There was a significant difference between young normal patients and patients being treated for glaucoma in CCT, C/D ratio, C/D ratio asymmetry, disc area, and N-RRA. Conclusion: More than one in five (22.96%) young normal patients has ocular structure findings similar to those found in patients being treated for glaucoma. These results will help refine decisions on which primary eye care patient to screen for glaucoma.

BACKGROUND:Many clinicians have noted that patients demonstrate a myopic refractive change following Traumatic Brain Injury (TBI). This apparent myopic shift disappears with cycloplegia, yet stubbornly reappears as soon as the pharmaceutical effect wears off. We propose that this shift is secondary to an irritative lesion that affects the parasympathetic innervation, resulting in ciliary body contracture. The dilemma for the clinician is whether to provide the immediate relief of clear distance vision by prescribing additional minus lenses, or to work toward attempting to re-establish the baseline refractive error.CASE REPORTS:The natural history of post-traumatic pseudomyopia in our experience involves one of the following three courses: (1) a transient condition that will occasionally resolve; (2) the typical case, a recalcitrant condition that will resolve under cycloplegic intervention, but immediately return as the cycloplegic wears off; or (3) a less-common subgroup of patients who continue to show an increase in myopia over time. Our description of these cases demonstrates management strategies (including atropinization) to relax accommodative spasm, traditional vision therapy techniques aimed at loosening the accommodative system, and refractive corrections.CONCLUSIONS:Pseudomyopia is one of many ocular and behavioral sequelae following TBI. By understanding the natural course and potential management options for post-traumatic pseudomyopia, the clinician will be better prepared to deal with these challenging cases. Flexibility is required, since options that work with one patient may prove ineffective with another. Counseling the patient as to potential outcomes given the natural history of this condition helps establish more-realistic expectations by the patients being treated.

PURPOSE:Patients often manifest symptoms that appear to be related to binocular distress. Many of these patients have normal heterophoria at distance and near, making the etiology of such symptoms perplexing. We performed a visual examination of patients having normal heterophoria at distance and near in order to investigate which visual analysis tests differentiate symptomatic from asymptomatic patients.METHODS:Eighty subjects (30 symptomatic, 50 asymptomatic) with ages between 18 to 35 years of either sex and any race were pooled based on vision-symptom level determined by a 9-question standardized visual-symptoms questionnaire scored using a 100-point scale (asymptomatic: score > or = 85; symptomatic: score < or = 75). Inclusion/exclusion criteria included vision correctable to 6/6 (20/20) Snellen acuity or better in each eye, normal phorias, no latent cyclovertical heterophoria, and normal ocular health.RESULTS:Of the 30 symptomatic patients, 18 had reduced vergence facility response using 3 pd base-in/12 pd base-out loose prism at distance (n = 10; t-score = 2.41, p < 0.02, d = 76) and near (n = 15; t-score = 3.32, p < 0.01, df = 78) with a significant difference beyond the 0.02 level. No other test including measurement of accommodation, showed a significant between-group difference. However, three patients with normal vergence facility (distance and near) showed a reduced binocular accommodative facility response (+/-2.00 D at 40 cm).CONCLUSION:Given a patent with asthenopia, normal phorias, and visual acuity, a differential diagnosis may be made based primarily on using vergence facility and accommodative facility testing. From a clinical standpoint, the results expedite diagnosis of binocular vision abnormalities and direct treatment.

BACKGROUND:Accommodative facility is commonly assessed using +/- 2.00 lenses at 40 cm. Significant differences have been demonstrated on binocular facility testing between symptomatic and asymptomatic children; studies on adults have not replicated these results. We evaluate the relation between symptoms and binocular amplitude-scaled facility (equivalent stimulus for each subject based on individual amplitude).METHODS:Optometry students (N = 98) and school children IN= 152) participated in a vision screening. A 9-question standardized questionnaire quantified symptoms. Binocular accommodative facility was assessed using random presentation of standard and amplitude-scaled facility, without knowledge of symptom level. Subjects with abnormal binocular vision were excluded from data analysis.RESULTS:For children, both amplitude-scaled (p = 0.0004). and standard accommodative facility (p = 0.0055) significantly differentiated symptomatic from asymptomatic responses. For adults, amplitude-scaled responses were significantly different (p= 0.0228) between symptomatic and asymptomatic subjects; standard testing results were not (p = 0.2013).CONCLUSION:Binocular amplitude-scaled facility testing (test distance 45%, lens power range 30% of push-up amplitude) identifies symptomatic adults at high significance level. And both children and adults perform similarly on amplitude-scaled testing. These results suggest that amplitude-scaled binocular accommodative facility should be the test of choice for evaluation of patients between the age of 8 years and the onset of presbyopia. Patients who perform less than 10 cycles per minute are likely to be symptomatic.

BACKGROUND:Standard accommodative facility testing, using +/- 2.00 D lenses @ 40 cm, stresses a much different proportion of the available accommodation for a 10-year-old patient with a binocular accommodative amplitude of 12 D and a 35-year-old patient with a binocular amplitude of 5 D. This may explain why research using adult subjects has failed to associate reduced accommodative facility with symptoms.METHODS:For 19 adult subjects with normal age-related amplitudes of accommodation, accommodative facility was measured with the standard test (+/- 2.00 D @ 40 cm) and 36 experimental combinations of test distance demand and lens power range, based on percentages of each individual's amplitude. In a masked study. these results were compared to symptom scores, quantified by a 9-item quality of vision questionnaire.RESULTS:The strongest relation of facility with symptoms was for the 75% distance demand/30% power range (p = 0.0216), with six other combinations also significant. The standard test combination did not significantly differentiate symptomatic from asymptomatic subjects (p = 0.1 515). The combination of the 45% distance demand/30% power range was significantly related to symptom score (p = 0.0315; r = -0.47603).CONCLUSION:Amplitude scaled facility testing provides the same percentage test distance and range of amplitude stimulated for all patients. The 45%/30% test combination differentiates symptomatic from asymptomatic subjects better than the standard test (+/- 2.00 D @ 40 cm) and is the one we suggest for future clinical investigation. Care should be taken when testing symptomatic patients over a long period of time, as they may compensate by relying on a predictor operator during the highly repetitive accommodative facility test, thus achieving a more-rapid response.

Saturday, December 14, 2002: Posters: Binocular Vision, Pediatric Optometry, Public Health, Vision Science: PDF Only

BACKGROUND:Accommodative facility testing is used in clinical care to assess functioning of the ocular accommodative system. The current clinical standard (binocular assessment using +/- 2.00 D lenses at 40 cm with a vectographic suppression check) was first described nearly 20 years ago as part of the last comprehensive review of the literature. The standard accommodative facility test imposes a variable requirement on patients of different ages who have a wide range of accommodative amplitudes.METHOD:In this article, we critically reviewthe present body of literature on accommodative facility testing, with emphasis on the relation between symptoms, accommodative amplitude, and the results found during accommodative facility testing.RESULT:We include discussion of the five broad categories of accommodative facility studies: (11 recommendations for testing criteria; (2) normative data investigations; (3) reliability and variability assessment; (4) relation between accommodative facility and symptoms; and (5) other relationships (e.g., effect of test parameters on accommodative facility).CONCLUSION:Given the substantial variation in demand when testing patients of different ages (amplitudes), it is not surprising that a significant variation in responses has been reported in the clinical accommodative facility literature. Future clinical investigation of accommodative facility would benefit from a systematic investigation into the relationship between age and amplitude. The presence or absence of symptoms needs to be considered so that results of testing can be analyzed in relation to the severity of binocular vision-related symptoms.

Saturday, December 8, 2001. Posters: Academy Information, Cornea and Contact lenses, Ocular Disease, Optics and Refraction, Vision Science, Visual Biology: PDF Only

1PRIVATE PRACTICE, OAKVILLE, ONTARIO, CANADA; 2University of Houston, College of Optometry, Houston, TX.

London, Richard OD, MA1; Wick, Bruce OD, PhD2; Eldred, Kia OD2; Laukannen, Hannu OD, MED3 Author Information

Jackson, Julie A. RN, OD; Westin, Elizabeth OD; Mathur, Ruchira BS; Wick, Bruce OD, PhD; Beaty, Samantha Turner OD; Miller, William OD, PhD; Hu, Ying-Sheng PhD Author Information

Gall, Ronald OD, MS1; Wick, Bruce OD, PhD2; Bedell, Harold E PhD2; Pease, Paul L OD, PhD2 Author Information

Wick, Bruce OD, PhD1; Kuether, Christian L BM1; Gall, Ronald OD, MS3 Author Information

Prepresbyopic patients with reduced accommodative amplitude (accommodative insufficiency) are commonly seen in optometric practice. Treatments include accommodative therapy and plus reading lenses. We did a prospective study of the effects of vision therapy and plus reading lenses on 15 patients (mean age 21.87 +/- 9.66 years) with accommodative insufficiency; presumed etiologies included head trauma (6 patients), thyroid disease (3 patients), seizures (1 patient), toxoplasmosis (1 patient), and idiopathic causes (4 patients). A 7-question scaled response pre- and post-treatment questionnaire assessed symptoms of two groups, vision therapy (idiopathic only) and progressive addition lenses (all patients). No idiopathic patient improved after 3 weeks of accommodative therapy. Progressive lenses with a near addition of + 1.00 or + 1.25 were then prescribed. Questionnaire results, which indicate that near additions provided more relief of symptoms than vision therapy for treatment of accommodation insufficiency, underscore the need for careful examination of prepresbyopic patients to determine those who would benefit from a near addition.