Can Imaging of Temporal Raphe Orientation with fundusphotos or SD-OCT be helpful for the Assessment of Ocular Torsion in Patients with Cranial Nerve Four Paresis?

Strabismic deviations can be horizontal, vertical, cyclorotational, or a combination of all three. Previous literature has established the difference between subjective and traditional objective torsional angles; however, often there is a failure to consider the physiological position of a normal fovea-optic nerve head (ONH) relationship. Using the temporal raphe (TR) orientation has been suggested as a solution for this discrepancy. The current study, approved by IWK Health Center research ethics board was created to assess the viability of using the TR in assessment of ocular torsion as well as investigate the effect of the physiological position of the fundus. Subjective tests were compared to traditional fundus photographs and novel TR scans in patients with long-standing unilateral fourth nerve palsies. Results found no differences between subjective and objective angles when considering the physiological fundus position and that TR angles were not comparable to other torsional testing methods. Therefore, it was concluded that the physiological position should be considered when determining the true amount of abnormal fundus torsion. As well, we found no significant value to using TR imaging by optical coherence tomography compared to the traditional fovea-ONH relationship by fundus photography to assess ocular torsion.

Predictability of horizontal versus vertical muscle surgery outcomes in thyroid eye disease.

Surgical repair of vertical muscles in thyroid eye disease (TED) is believed to yield more unpredictable results than horizontal muscle surgery. The purpose of this study is to determine if the short-term outcomes for strabismus surgery in TED are equally predictable for horizontal and vertical muscle surgery. We retrospectively reviewed the charts of 27 consecutive patients who underwent strabismus surgery for TED from a single surgeon's practice. Eligibility for inclusion in the study included biochemically stable thyroid disease for at least a year and stable orthoptic measurements for at least 6 months prior to surgery. Nine patients had surgery only on vertical rectus muscles, three only on horizontal, and fifteen on both vertical and horizontal rectus muscles. Mean follow-up was 2.4 ± 5.2 months. In primary gaze at 6 m, a mean horizontal deviation of 16.6 ± 22.3 PD, and a mean vertical deviation of 19.7 ± 14.1 PD were measured pre-operatively. Post-operatively, this measured 2.3 ± 8.4 PD horizontally and 2.1 ± 7.8 PD vertically (p = 0.933). There was no statistically significant difference between post-operative horizontal and vertical deviations in elevation, depression, adduction, and abduction. Nine patients required reoperation to attain satisfactory ocular alignment; seven of these cases involved repeat surgery on vertical muscles, while two cases required operation on both horizontal and vertical muscles. Results suggest that surgical outcomes of both horizontal and vertical muscle surgery are equally predictable in stable TED; however, reoperation rates were higher for vertical muscles compared to horizontal muscles.

Has rising pediatric obesity increased the incidence of idiopathic intracranial hypertension in children?

OBJECTIVE: Idiopathic intracranial hypertension (IIH) in children is an uncommon but significant cause of morbidity, including permanent visual loss. It is important to understand if, like obesity, IIH in children is on the rise and is related to that increase. The aim of this study is to compare the recent incidence rate of pediatric IIH in a tertiary care hospital with earlier data published from that same hospital. DESIGN: Retrospective chart review. PARTICIPANTS: All children aged 2 to 16 years diagnosed with IIH at the IWK Health Centre in Halifax between 1997 and 2007. METHODS: Charts of eligible patients were reviewed to ensure all diagnostic criteria for IIH were met. Incidence and obesity rates were calculated based on data from Statistics Canada. RESULTS: Twelve cases (5 males, 7 females) fulfilling the diagnostic criteria for IIH were identified, for an annual incidence of 0.6 cases per 100,000 children with no sex predilection (p = 0.51). Obesity was noted in 75% of patients examined (9/12). Children older than 12 years were more likely to be obese (6/6, 100%) compared with those younger than 12 years (3/6, 50%). CONCLUSIONS: The calculated incidence is lower than that found in an earlier study for the same geographic region (0.9 cases per 100,000 children) despite increasing obesity rates. This decrease may be a reflection of improved diagnostic techniques or may indicate that factors other than obesity govern IIH predilection in younger children.

Error of calibration in ophthalmic calipers: a source of significant clinical errors.

OBJECTIVE: Length measuring instruments are frequently used in ophthalmic surgery practice. For all subspecialties, calipers need to be accurate. This study was carried out to identify errors of calibration in ophthalmic calipers as a potential source of significant clinical errors. DESIGN: This study is a descriptive research. METHODS: All Castroviejo calipers free of any visible damage and available to the ophthalmic surgeons in the operating room suites of our 2 affiliated hospitals were included. The caliper scale readings were compared to measurement markings on a standardized ruler at screening points of 1, 5, 10, and 15 mm on the ruler. Any caliper with a discrepancy of 0.5 mm or more at any set of these screening points went on to having further analysis. RESULTS: Seventy-one calipers were examined, of which 30 (42%) showed at least 1 caliper scale reading discrepancy of ≥0.5 mm as compared to ruler measurements. Errors of at least 1 mm were found in 6 of 30 calipers (20%). The majority of calipers underestimated lengths 22/30 (73%), whereas 27% overestimated. CONCLUSIONS: With close to half of the calipers inducing a 0.5 mm or more error, and with 20% of these at least 1 mm, significant clinical consequences could ensue: for example, in follow up of glaucomatous corneas in children, in measurements for anterior chamber intraocular lens sizing, in certain refractive surgery techniques, pars-plana sclerotomies, and intravitreal injection sites, or in measuring amounts in strabismus to name a few. Errors in calibration of ophthalmic calipers must be acknowledged and avoided.

Survey on allied health personnel in Canadian ophthalmology: the scalpel for change.

OBJECTIVE: To determine the recruiting and training needs for ophthalmic medical personnel (OMP), assess the value of their certification, and compare the ophthalmic practice productivity and performance of non-certified and certified OMP, as rated by both ophthalmologists and OMP. DESIGN: Comparative analysis. PARTICIPANTS: One hundred and sixteen Canadian ophthalmologists and 98 OMP. METHODS: An invitation to complete an online survey on OMP recruitment, training, certification, and productivity performance in a clinical setting was sent to 1081 ophthalmologists and OMP. RESULTS: Fifteen percent of ophthalmologists and 31% of OMP completed the survey. Ophthalmologists (61%) reported difficulty hiring OMP; employee referrals was the best method (40%). Awareness of formal OMP training programs was high and 50% of respondents supported developing additional training programs; 55% of OMP were encouraged by their employers to obtain certification. Personal challenge and achievement (79%) and improved skills (71%) were the main reasons for OMP to obtain certification. The majority of OMP and ophthalmologists felt that certified OMP enhanced most practice productivity measures. Higher wages associated with certification were reported by 73% of respondents. CONCLUSIONS: Training of qualified OMP was identified as a need by ophthalmologists. Ophthalmic practices can increase their overall productivity by adding certified OMP to their staff.

The hidden challenges of mixed amblyopia.

INTRODUCTION: This article will cover the subject of complex mixed amblyopia and its hidden challenges. Clarification of the terminology is followed by a clinical presentation of these difficult cases to illustrate their varied causes and many interactions. An examination of the evidence in the literature on treatment success is followed by a discussion on the challenges facing parents and members of the caring team in the management of complex mixed amblyopia. METHOD: This exposé is both a critical summary of the literature on the subject and the result of 25 years of clinical experience in a busy tertiary care pediatric ophthalmic practice. RESULTS: Very little high quality evidence is available on the results of the treatment of complex mixed amblyopia. Descriptive series, illustrative case reports and anecdotal comments are nevertheless a source of information worthy of careful consideration to help both orthopists and ophthalmologists involved. The severity of the loss of organic integrity, a realistic visual target, and close monitoring of the therapeutic efforts are essential components of a successful outcome. CONCLUSION: The treatment of complex mixed amblyopia is the ultimate test for the orthoptist. While the evidence in the literature is empirical at best, the diagnostic and therapeutic challenges it represents can nevertheless be met.

The method of treatment cessation and recurrence rate of amblyopia.

BACKGROUND AND PURPOSE: To date, much of the research regarding amblyopia has been focused on which therapeutic modality is the most efficacious in amblyopia management. Unfortunately, there is a lack of research into which method of treatment cessation is the most appropriate once therapy has been completed. The purpose of this study is to investigate if the cessation method affects the recurrence rate of amblyopia. METHODS: This study was a prospective randomized clinical trial of 20 subjects who were wearing full-time occlusion and were at the end point of their therapy. The subjects were randomized into one of two groups: abrupt cessation or therapy tapering. All subjects were followed for 3 consecutive 4-week intervals, for a total of 12 weeks, to assess the short-term recurrence rate of amblyopia. Subjects who were in the tapered group had their occlusion reduced from full-time occlusion (all waking hours minus one) to 50% of waking hours at study enrollment (i.e., from 12 hours/day to 6 hours per day); occlusion was reduced by an additional 50% at the first 4-week study visit (i.e., from 6 hours/day to 3 hours), with occlusion being discontinued completely at the week 8 visit. All subjects who were in the abrupt cessation group had their full-time occlusion discontinued completely at the start of the study (i.e., from 12 hours/day to none). Additional assessments were also conducted at week 26 and week 52 post-therapy cessation to determine the longer term amblyopia regression rate. For the purposes of this study, recurrence was defined as a 0.2 (10 letters) or more logarithm of the minimum angle of resolution (logMAR) loss of visual acuity. RESULTS: A recurrence of amblyopia occurred in 4 of 17 (24%; CI 9%-47%) participants completing the study by the week 52 study end point. There were 2 subjects from each treatment group who demonstrated a study protocol-defined recurrence. CONCLUSION: There was a 24% risk of amblyopia recurrence if therapy was discontinued abruptly or tapered in 8 weeks. In this small sample, the assigned cessation method did not affect the rate of amblyopia recurrence. It is recognized that the smaller sample size in our study prevents us from making definitive conclusions on the potential role that abrupt cessation has on the regression rate of amblyopia. The sample size was too small to reach an acceptable level of statistical power; therefore the generalizability of the findings to the broad population of all patients with amblyopia requires continuing research. This study therefore could be considered as a pilot study.

Stability of visual acuity after the cessation of amblyopia treatment: review of the literature.

INTRODUCTION AND PURPOSE: The treatment of amblyopia in children is frequently discussed in the literature. Less attention, however, has been given to the durability of the visual acuity results attained with therapy. The objective of this review is to conduct an in-depth analysis of the existing literature, on the stability of visual acuity following cessation of amblyopia treatment, and to identify any gaps in the literature, which could guide future investigations. RESULTS: There did not appear to be any one consistent risk factor affecting the stability of vision after cessation of amblyopia treatment. Most of the reviewed studies varied with respect to lengths of follow-up visits, patient population, and method of visual acuity assessment. There was also a generalized lack of standardization of visual acuity measurements in these previous investigations. Only one of the studies analyzed was a prospective design. CONCLUSION: The area of study in amblyopia is fraught with contradictions. It is obvious from this review that there exists uncertainty regarding the recurrence of amblyopia following treatment. Previous studies have failed to identify any common, predictive, influencing factors necessary for the maintenance of visual acuity after cessation of therapy. Also lacking is discussion on the potential role that therapy tapering plays in the recurrence of amblyopia following the cessation of treatment.

Controversy in amblyopia management.

BACKGROUND AND PURPOSE: Much has been written about amblyopia treatment. However, there is no consensus on the most efficacious therapeutic modality for amblyopia. The intensity of therapy needed to maximize visual acuity is also widely debated. The diversity of opinions emphasizes that the optimum treatment for amblyopia is unknown. Part of the uncertainty stems from the lack of standardization in the management of amblyopia. The objective of this paper is to conduct an in-depth review of the literature in an attempt to clarify the amblyopia treatment conundrum. CONCLUSIONS: The treatment of amblyopia in children is frequently discussed in the literature. It is obvious from the literature that there is the need for prospective studies with consistent controls, clear definitions of what constitutes successful therapy endpoints, and standardization of testing procedures.

Negative predictive value of a vision screening program aimed at children aged 3 to 4 years old.

PURPOSE: Nova Scotia has a vision screening program which assesses children aged 4[1\2] to 5[1\2] years. However, its use in younger children proved impossible. This study will examine a modified screening protocol for the younger children (3 to 4 years old) and determine its negative predictive value and minimum age for reliable application. MATERIALS AND METHODS: Public health nurses administered the study protocol to 3- to 4-year-old children. One hundred seventy-eight children were screened over two summers. Medical and family history, external inspection, as well as measures of visual acuity with the Lea Hyvarinen symbols chart and stereoacuity with Frisby plates were recorded. Results were compared with a gold standard examination that included full orthoptic and ophthalmologic evaluations. One hundred forty-one (79%) children underwent the gold standard examination. Agreement between screening and gold standard examinations was studied. RESULTS: Data showed increased concordance between screening and gold standard examination results with increasing age up to 41 months. Negative predictive value (NPV) and specificity also improved when data were separated by this age. In children <41 months old, the screening test NPV was 90%, specificity, 68%, and sensitivity, 75%. In comparison, children >/=41 months old had screening test NPV of 96%, specificity, 95%, and sensitivity, 50%. Specificity was higher in the older age group ( P < 0.001). Sensitivity was lower ( P = 0.004). CONCLUSION: This study's vision screening protocol appears better suited for children 41 months and older. They had better pass/fail reproducibility than children <41 months. The test's simplicity allows easy use by non-eye-care professionals. It could potentially lower the reliable screening age of children by 13 months, from 54 months of age (4[1\2] years old) to 41 months. This screening may miss some refractive errors and microtropia/monofixation syndrome, despite normal visual acuity, stereoacuity, and external inspection.