Primary Low Grade Follicular Lymphoma of the Conjunctivae Mimicking Nodular Anterior Scleritis: A Case Report.

Conjunctival lymphomas are rare entities and may present with non-specific ocular signs that resemble inflammation. They may mimic common ocular pathologies, leading to a delay in diagnosis and treatment. The treatment options of conjunctival lymphomas should be tailored to individuals due to their indolent nature compared to other adnexal lymphomas. Herein, the authors report a case of a primary follicular conjunctival lymphoma in a patient who presented with signs and symptoms of nodular anterior scleritis. The final histology of the conjunctiva lesion revealed primary follicular lymphoma. The patient was managed conservatively with active surveillance.

Corneal thickness and volume in subclinical and clinical keratoconus.

To evaluate corneal thickness and volume in subclinical and clinical keratoconus in Asian population with the aim of discriminating between normal and ectatic cornea. Eyes were placed into one of the following three groups: normal, subclinical, and mild-moderate keratoconus. Pentacam Scheimpflug imaging (Oculus Inc., Wetzlar, Germany) was performed for each participant to record thinnest corneal thickness, central corneal thickness, corneal volume (CV), peripheral corneal thickness (PCT) and percentage thickness increase (PTI) at 2, 4, 6, and 8 mm. The data were exported to SPSS for statistical analysis. Subjects comprised 52 normal, 15 subclinical keratoconus, and 32 mild-moderate clinical keratoconus eyes. Our results indicated that corneal thickness (CT) distribution, PTI, and CV in normal eyes were significantly different compared with subclinical and clinical keratoconus (P < .05). Overall, subclinical group exhibited lower CT distribution and volume, and higher PTI in comparison with normal eyes. However, they showed higher CT distribution and volume, and lower PTI compared with keratoconus group. In addition, there was a smaller change in PCT and PTI from the thinnest point of the cornea to the periphery. The results of the present study indicate that CT parameters and CV were significantly different in normal versus subclinical group and in normal versus keratoconus group. These findings could help clinicians to better discriminate between normal and ectatic cornea.

Repeatability of corneal first-surface wavefront aberrations measured with Pentacam corneal topography.

PURPOSE: To assess the repeatability of corneal wavefront aberrations derived from Pentacam (Oculus) corneal topography. SETTING: Flinders Eye Centre, Flinders Medical Centre, Bedford Park, South Australia, Australia. METHODS: Forty-five normal participants and 10 participants with keratoconus were tested. Intraobserver and interobserver repeatability was determined using 4 observers within and between sessions. Topographical maps were exported to external software, and corneal first-surface wavefront aberrations were calculated using a 10th-order Zernike expansion over a 6.0 mm optical zone. Repeatability was determined with Bland-Altman limits of agreement and expressed as the coefficient of repeatability (COR). RESULTS: Initial data showed high wavefront aberrations in normal participants and poor repeatability. Topographical maps showed extrapolated topography in zones without data acquisition; maps with less than 6.0 mm of complete data were excluded in the final analysis. The mean wavefront aberrations for normal participants remained high, but repeatability improved. The COR relative to the magnitude of wavefront aberrations was high (average 100%) across all modal pairs and orders, although best for total higher-order root mean square. Participants with keratoconus had higher magnitude wavefront aberrations and poorer repeatability but similar COR to average wavefront aberration ratios. Examination of raw elevation data showed poor repeatability. CONCLUSIONS: Wavefront aberrations calculated from Pentacam corneal topography were large in magnitude, and reliability was poor, largely due to variability in corneal elevation data. Intraobserver and interobserver reliability within and between sessions was comparable. The Pentacam was not reliable in measuring corneal wavefront aberrations.

Anterior segment biometry with the Pentacam: comprehensive assessment of repeatability of automated measurements.

PURPOSE: To comprehensively assess the reliability of automated Pentacam (Oculus, Inc.) measurements. SETTING: Flinders Eye Centre, Flinders Medical Centre, Bedford Park, South Australia, Australia. METHODS: Both eyes of 35 normal volunteers were tested twice on the same day by 2 different observers. All automated values were recorded, and manual analysis of topographic maps was performed only to overrule variance in corneal thickness due to pupil decentration altering the central reference point. Repeatability was determined with Bland-Altman limits of agreement and reported as the coefficient of repeatability (COR = +/-1.96 standard deviation of differences). Relative repeatability (RR) was calculated as a percentage of the ratio of COR to the mean. RESULTS: Overall, repeatability was good. Corneal curvature, reported in diopters, showed good repeatability anteriorly (simulated keratometry mean COR+/-0.28D; RR=0.64%) and posteriorly (COR+/-011D; RR=1.85%). Peripheral corneal curvature was more reliable when calculated by the sagittal (axial) method (RR=1.57%) than by the tangential (meridional) method (RR=2.38%). Keratometric power deviation was less reliable (RR=16.39%). Anterior chamber measurements showed good reliability (RR=3.07%-5.68%) except for anterior chamber angle (RR=14.41%). Pupil diameter showed poor reliability (RR=25.77%). Central corneal thickness was comparable at pupil center and corneal vertex, but peripheral repeatability was much better when centered on the corneal vertex (COR+/-16.00microm; RR=2.56%) than at pupil center (COR+/-26.28microm; RR=4.23%). CONCLUSIONS: Pentacam corneal curvature and anterior chamber parameters were highly repeatable, but pupil measurements had poor repeatability. Peripheral pachymetry readings were affected by pupil decentration and required manual analysis using the corneal vertex as the point of reference to achieve good repeatability.