Cindy X. Cai

A Comparison of Progressive Loss of the Ellipsoid Zone (EZ) Band in Autosomal Dominant and X-Linked Retinitis Pigmentosa

PURPOSE In patients with retinitis pigmentosa (RP), the inner segment ellipsoid zone (EZ; also known as the inner segment/outer segment [IS/OS] border) is a marker of the usable visual field at a given point in time and of the progression of the disease over time. Here we compare the change in the width per year of the EZ band in patients with autosomal dominant (ad) and x-linked (xl) RP. METHODS Using optical coherence tomography (OCT), 9-mm horizontal and vertical line scans through the fovea were obtained for one eye of 26 xlRP patients and 33 adRP patients. Scans were repeated on average 2.0 years later (range, 0.6-4.8 years). Using a manual segmentation procedure, the EZ band was delineated and its horizontal width (HW) and vertical width (VW) were determined. RESULTS The adRP and xlRP patients had similar initial EZ HW (xlRP: 11.8 ± 5.4°, adRP: 12.4 ± 6.3°, P = 0.69) and VW (xlRP: 8.5 ± 4.9°, adRP: 11.4 ± 7.1°, P = 0.09). However, between visits the absolute loss and percent loss of the EZ width per year was significantly greater for xlRP than adRP for both HW (xlRP: 1.0 ± 0.6°/y, 9.6 ± 5.6%/y; adRP: 0.4 ± 0.5°/y, 3.4 ± 5.4%/y; P < 0.001) and VW (xlRP: 0.8 ± 0.8°/y, 9.2 ± 8.9%/y; adRP: 0.3 ± 0.5°/y, 4.2 ± 6.4%/y; P < 0.01). There was a weak correlation between the loss of EZ width per year and the initial width for xlRP (r(2) = 0.17, P = 0.036), but no correlation for adRP (r(2) = 0.004, P = 0.73). The test-retest difference of EZ HW was 0.2 ± 0.5°. CONCLUSIONS The OCT data here support a faster rate of loss per year in the case of xlRP. (ClinicalTrials.gov number, NCT00100230.).

Reliability of a Manual Procedure for Marking the EZ Endpoint Location in Patients with Retinitis Pigmentosa

Purpose We developed and evaluated a training procedure for marking the endpoints of the ellipsoid zone (EZ), also known as the inner segment/outer segment (IS/OS) border, on frequency domain optical coherence tomography (fdOCT) scans from patients with retinitis pigmentosa (RP). Methods A manual for marking EZ endpoints was developed and used to train 2 inexperienced graders. After training, an experienced grader and the 2 trained graders marked the endpoints on fdOCT horizontal line scans through the macula from 45 patients with RP. They marked the endpoints on these same scans again 1 month later. Results Intragrader agreement was excellent. The intraclass correlation coefficient (ICC) was 0.99, the average difference of endpoint locations (19.6 μm) was close to 0 μm, and the 95% limits were between −284 and 323 μm, approximately ±1.1°. Intergrader agreement also was excellent. The ICC values were 0.98 (time 1) and 0.97 (time 2), the average difference among graders was close to zero, and the 95% limits of these differences was less than 350 μm, approximately 1.2°, for both test times. Conclusions While automated algorithms are becoming increasingly accurate, EZ endpoints still have to be verified manually and corrected when necessary. With training, the inter- and intragrader agreement of manually marked endpoints is excellent. Translational Relevance For clinical studies, the EZ endpoints can be marked by hand if a training procedure, including a manual, is used. The endpoint confidence intervals, well under ±2.0°, are considerably smaller than the 6° spacing for the typically used static visual field.

Downbeat nystagmus secondary to familial hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis is a rare autosomal recessive disorder characterized by severe inflammation induced by defective natural killer cell function, which triggers a state of highly stimulated but ineffective immune response. This disorder can affect multiple organ systems, and neurologic manifestations include irritability, seizures, impaired consciousness, meningismus, and cranial nerve palsies. We describe a unique case of hemophagocytic lymphohistiocytosis in which downbeat nystagmus developed due to cerebellar swelling with compression of the cervicomedullary junction.

Intravitreal Bevacizumab for Proliferative Sickle Retinopathy: A Case Series:

Purpose: To report outcomes of intravitreal bevacizumab therapy for proliferative sickle retinopathy (PSR). Methods: A retrospective, interventional case series. Five eyes of 5 patients with PSR were managed with intravitreal bevacizumab therapy over a 13-year period at a single institution. Results: Four patients had sickle cell-hemoglobin SC disease and 1 had sickle cell-beta thalassemia disease. Four of the patients treated with intravitreal bevacizumab injection were treated for recurrent vitreous hemorrhage and 1 was treated for new peripheral sea fan neovascularization. In those patients treated for vitreous hemorrhage, there was improvement in visual acuity as early as 2 weeks after treatment. Only 2 of the patients had documented recurrent vitreous hemorrhage during the period of follow-up after the initial injection. In 1 patient, the vitreous hemorrhage did not recur until 13 months after the injection. All patients showed an anatomic response to intravitreal bevacizumab therapy with partial regression of the peripheral sea fan neovascularization. All patients tolerated the injections without any complications. Conclusions: Intravitreal bevacizumab injections appear to be well tolerated and may be an effective treatment of PSR. Regression of peripheral sea fan neovascularization and decreased duration of vitreous hemorrhage may be observed. Large-scale randomized controlled trials are needed to further clarify the role of bevacizumab in PSR.