Comparison of central and peripheral corneal thickness measurements with scanning-slit, Scheimpflug and Fourier-domain ocular coherence tomography.

PURPOSE: To compare central, regional and relational corneal thickness values obtained with multiple technologies in normal patients and to determine their equivalence and interchangeability. METHODS: Retrospective analysis of 100 eyes from 50 patients evaluated by ultrasound pachymetry (Pachette II), scanning-slit (Orbscan II), Scheimpflug (Pentacam HR) and spectral-domain ocular coherence tomography (OCT) (RTVue-100) obtained as average values (OCT-A) and point measurements (OCT-P). Measurements included central corneal thickness (CCT) for all technologies and thinnest corneal thickness for scanning-slit, Scheimpflug and OCT. Peripheral thickness measurements were obtained at the 3 mm radius in the superior (S), nasal (N), inferior (I) and temporal (T) regions. RESULTS: CCT values were: 563.9±36.1µ ultrasound, 570.9±36.1µ scanning-slit, 552.8±33.8µ Scheimpflug, 550.5±32.7µ (OCT-A), 549.4±32.7µ (OCT-P). Ultrasound and scanning-slit were significantly different from each other (p<0.0001), and both were significantly different from all other devices (p<0.0001), while Scheimpflug was similar to OCT-A and OCT-P (p=0.4). Differences between CCT and thinnest corneal thickness were significantly different from all technologies except scanning-slit and OCT-A. For peripheral values, almost all locations' measurements were significantly different from one another (p<0.0001). Superior-inferior values and ratios were also significantly different from one another for almost all devices with no consistent patterns detectible. CONCLUSIONS: There are significant clinically relevant differences between regional and relational thickness measurements obtained with ultrasound, scanning-slit, Scheimpflug and OCT devices. Screening metrics devised for one system do not appear directly applicable to other measurement systems.

Bilateral central retinal artery occlusion associated with herpes simplex virus-associated acute retinal necrosis and meningitis: case report and literature review.

A 60-year-old woman with a history of recurrent headaches and blurred vision presented with bilateral optic disc edema. Optic neuritis was suspected, and intravenous methylprednisonlone was administered. Her vision declined to hand motions in both eyes, and subsequent evaluation revealed bilateral acute retinal necrosis with bilateral central retinal artery occlusions (CRAO). Aqueous humor polymerase chain reaction analysis was positive for herpes simplex virus (HSV), establishing a diagnosis of HSV-associated bilateral acute retinal necrosis (ARN) and meningitis. CRAO has rarely been reported in association with ARN, and a fulminant course with bilateral CRAO in association with ARN has not been previously reported. This case emphasizes the importance of careful peripheral examination in patients with presumptive optic neuritis, judicious use of systemic corticosteroid in this context, and the retinal vaso-obliterative findings that may be observed in the pathogenesis of ARN.

Therapeutic flap amputation for atypical LASIK flap and interface abnormalities.

PURPOSE: To describe LASIK flap amputation as a therapeutic option for patients with atypical refractory flap complications. METHODS: Case series and literature review. RESULTS: Seven eyes of 6 patients underwent flap amputation for various atypical indications, including non-infectious flap/interface opacity (3 patients), irregular astigmatism on the flap surface (3 patients), and chronic pain (concurrent in 2 patients with irregular astigmatism). In each case, conservative measures were ineffective. All patients had symptomatic improvement and improved corrected visual function after amputation; however, uncorrected distance visual acuity worsened in 2 patients, manifest refraction worsened in 3 patients, and irregular astigmatism increased in 2 patients. CONCLUSIONS: Flap amputation is a reasonable alternative to improve corrected acuity in select cases with significant flap opacities or irregular astigmatism unresponsive to conservative measures, but uncorrected acuity and irregular astigmatism may worsen and should be discussed during the informed consent process.

Reticulohistiocytoma of the orbit.

Reticulohistiocytoma is a rare, benign histiocytic proliferation of the skin or soft tissue. While ocular involvement has been documented in the past, there have been no previously reported cases of reticulohistiocytoma of the orbit. In this report, the authors describe a reticulohistiocytoma of the orbit in a middle-aged woman.