Yasmin S. Bradfield

Comparison of Tono-Pen and Goldmann applanation tonometers for measurement of intraocular pressure in healthy children

PURPOSE To assess the agreement of intraocular pressure (IOP) measured with the Tono-Pen and the Goldmann applanation tonometer (GAT) in normal children and adolescents. METHODS A total of 439 subjects from birth to <18 years of age without anterior segment anomalies or glaucoma had their IOP measured with the two instruments by separate, masked examiners in the office or under general anesthesia. RESULTS On average, the Tono-Pen measured values slightly lower than the GAT for IOP <11 mm Hg and slightly higher than the GAT for IOP >11 mm Hg in the office setting. Using the average of GAT and Tono-Pen IOPs to estimate the true IOP, the average difference (GAT - Tono-Pen) was 0.4 mm Hg at IOP of 10 mm Hg and -3.0 mm Hg at IOP of 20 mm Hg. The 95% limits of agreement on the average difference between instruments were ± 6.4 mm Hg in the office setting and ± 6.8 mm Hg under general anesthesia. Larger differences between instruments were found with younger age. Standard error of measurement with the Tono-Pen was 1.44 mm Hg and 1.82 mm Hg for the office and anesthesia settings, respectively. Thicker corneas were associated with higher IOP with both the GAT and the Tono-Pen. CONCLUSIONS In normal children, average differences between IOP measured by Tono-Pen and GAT were small, although there was substantial test-retest variability. Younger age was associated with larger average differences, as was higher IOP in the office setting.

Angiopoietin-1 is required for Schlemm’s canal development in mice and humans

Primary congenital glaucoma (PCG) is a leading cause of blindness in children worldwide and is caused by developmental defects in 2 aqueous humor outflow structures, Schlemm’s canal (SC) and the trabecular meshwork. We previously identified loss-of-function mutations in the angiopoietin (ANGPT) receptor TEK in families with PCG and showed that ANGPT/TEK signaling is essential for SC development. Here, we describe roles for the major ANGPT ligands in the development of the aqueous outflow pathway. We determined that ANGPT1 is essential for SC development, and that Angpt1-knockout mice form a severely hypomorphic canal with elevated intraocular pressure. By contrast, ANGPT2 was dispensable, although mice deficient in both Angpt1 and Angpt2 completely lacked SC, indicating that ANGPT2 compensates for the loss of ANGPT1. In addition, we identified 3 human subjects with rare ANGPT1 variants within an international cohort of 284 PCG patients. Loss of function in 2 of the 3 patient alleles was observed by functional analysis of ANGPT1 variants in a combined in silico, in vitro, and in vivo approach, supporting a causative role for ANGPT1 in disease. By linking ANGPT1 with PCG, these results highlight the importance of ANGPT/TEK signaling in glaucoma pathogenesis and identify a candidate target for therapeutic development.

Outcomes of Harada-Ito surgery for acquired torsional diplopia

PURPOSE To evaluate the outcomes of Harada-Ito surgery in correcting various types of torsional diplopia. METHODS The medical records of patients who underwent Harada-Ito surgery at two academic institutions were retrospectively reviewed. Data collected included etiology of torsional diplopia, strabismus and torsion measurements, reoperation rate, patient symptoms, and use of prism. Postoperative success was defined as a lack of diplopia in the primary position at distance and downgaze at near with or without prism. Failure was defined as persistent torsional diplopia; partial success was defined as surgical success but with restrictive strabismus in the secondary gaze positions. RESULTS A total of 26 patients (mean age, 46 years; range, 13-89 years) were included. Of these, 17 had superior oblique palsy. The mean follow-up duration was 2 years (range, 2-60 months). The surgical outcome was success in 73% of patients, partial success in 7%, and failure in 19%. All patients with ≤10° of torsion preoperatively obtained surgical success. Patients in the failure group had higher amounts of preoperative torsion compared to the success group (P = 0.009). The reoperation rate was 23%, including four patients with additional surgery for downgaze esotropia or torsion. One-third of the patients wore a prism immediately after surgery. CONCLUSIONS Harada-Ito surgery successfully treated torsional diplopia. Patients with ≤10° of preoperative torsion had a better outcome. Downgaze diplopia was a common reason for additional surgery.

Surgical management of clinically significant hypertropia associated with exotropia

PURPOSE To report the surgical treatment of hypertropia coexisting with exotropia, with either vertical offset surgery or additional vertical muscle surgery simultaneous to correction of the exotropia. METHODS A total of 35 patients with exotropia and hypertropia who underwent a horizontal muscle surgery for exotropia were included. To determine efficacy in resolving a vertical deviation in patients with exotropia, 28 patients were compared in 2 groups: those who underwent horizontal muscle surgery with vertical offset and those who underwent horizontal muscle surgery with additional vertical muscle surgery. An additional 7 patients who had exotropia and hypertropia but did not undergo vertically corrective surgery were included for comparison. RESULTS Vertical offset of horizontal rectus muscles (4 mm) resulted in 8(Delta) correction of the distance hypertropia. Vertical rectus muscle recession used in the treatment of larger hypertropic deviations with exotropia had a 3(Delta) correction per 1 mm of recession. Success rates for hypertropia correction were similar between groups, 63% vertical offset and 71% vertical muscle groups; overcorrections occurred in 29% of the vertical muscle group. The vertical correction in both groups was stable in 88% over 6 months postoperatively. CONCLUSIONS Vertical offset of the horizontal muscles simultaneous with exotropia correction has a beneficial effect in small-angle hypertropia (<14(Delta)). Vertical rectus muscle surgery in patients with hypertropia greater than 10(Delta) had equivalent success; however, in intermittent exotropia the hypertropia was prone to overcorrection.

Chorioretinopathy and Microcephaly with Normal Development

Purpose: To report a pediatric patient with bilateral chorioretinopathy and microcephaly who from birth to 2 years of age is reaching appropriate developmental milestones.Design: Retrospective case report with clinical findings and literature review. Main Outcome Measures: Clinical findings and visual acuity estimated by sweep visual evoked potentials (VEP), electroretinogram (ERG) and fundoscopic exam. Results: A microcephalic child with normal motor and cognitive development had improving sweep VEP despite atypical fundoscopic findings of bilateral chorioretinopathy, attenuated retinal vessels, and anomalous optic nerves. The etiology for these collective findings despite extensive workup, including prenatal TORCH titers and neuro-imaging, has remained unidentified. Conclusions: Most published cases of microcephaly with chorioretinopathy have described patients with mild to severe mental retardation. Patients with chorioretinopathy and microcephaly may, however, reach all developmental milestones with improvement in visual development as was seen in this case. The long-term cognitive and visual prognosis may be better than previously reported.

Intraobserver reliability of contact pachymetry in children

BACKGROUND Central corneal thickness (CCT) is an important measurement in the treatment and management of pediatric glaucoma and potentially of refractive error, but data regarding reliability of CCT measurement in children are limited. The purpose of this study was to evaluate the reliability of CCT measurement with the use of handheld contact pachymetry in children. METHODS We conducted a multicenter intraobserver test-retest reliability study of more than 3,400 healthy eyes in children aged from newborn to 17 years by using a handheld contact pachymeter (Pachmate DGH55; DGH Technology Inc, Exton, PA) in 2 clinical settings--with the use of topical anesthesia in the office and with the patient under general anesthesia in a surgical facility. RESULTS The overall standard error of measurement, including only measurements with standard deviation ≤5 μm, was 8 μm; the corresponding coefficient of repeatability, or limits within which 95% of test-retest differences fell, was ±22.3 μm. However, standard error of measurement increased as CCT increased, from 6.8 μm for CCT less than 525 μm, to 12.9 μm for CCT 625 μm and greater. The standard error of measurement including measurements with standard deviation >5 μm was 10.5 μm. Age, sex, race/ethnicity group, and examination setting did not influence the magnitude of test-retest differences. CONCLUSIONS CCT measurement reliability in children via the Pachmate DGH55 handheld contact pachymeter is similar to that reported for adults. Because thicker CCT measurements are less reliable than thinner measurements, a second measure may be helpful when the first exceeds 575 μm. Reliability is also improved by disregarding measurements with instrument-reported standard deviations >5 μm.

Cervical lymphadenopathy secondary to rhabdomyosarcoma presenting as Horner syndrome in an infant

A 4-week-old boy with left ptosis, anisocoria, and a mass on his left hand was diagnosed with Horner syndrome. The diagnosis precipitated a work-up for a possible malignant etiology. Magnetic resonance imaging demonstrated enlarged left cervical and axillary lymph nodes. A biopsy of the hand lesion confirmed embryonal rhabdomyosarcoma, but a biopsy of the axillary lymph node was negative. Mechanical pressure by noncancerous enlarged lymph nodes is hypothesized to cause the Horner syndrome.

Successful treatment of anisometropic amblyopia with spectacles alone

BACKGROUND The efficacy of treating anisometropic amblyopia with occlusion therapy is well known. However, this form of treatment can be associated with risks. Spectacle correction alone may be a successful and underutilized form of treatment. METHODS The records of 28 patients treated successfully for anisometropic amblyopia with glasses alone were reviewed. Age, initial visual acuity and stereoacuity, and nature of anisometropia were analyzed to assess associations with time required for resolution, final visual acuity, and stereoacuity. Incidence of amblyopia recurrence and results of subsequent treatment, including patching, were also studied. RESULTS Mean time to amblyopia resolution (interocular acuity difference <or=1 line) was 5.8 months (range 2 to 15 months). Worse best corrected initial visual acuity was associated with longer time to resolution (Spearmans rho = 0.37, P = 0.05), while age, initial stereoacuity, amount, and type of anisometropia were not (P = 0.43, 0.68, 0.26, 0.47, respectively). None of the astigmatic or myopic patients achieved visual acuity of 20/20 in the amblyopic eye, while seven (39%) of the hyperopic patients did. This difference was significant (P = 0.03). Better initial stereoacuity predicted good final stereoacuity (P = 0.01). Only four (14%) patients developed amblyopia recurrence over an average follow-up period of 1.7 years. All were successfully treated with updated spectacles or patching. CONCLUSIONS Treatment of anisometropic amblyopia with spectacles alone can be a successful option. Patients treated with spectacles alone may experience a lower amblyopia recurrence rate than those treated with occlusion therapy.