Faculty Bibliography

PURPOSE: Optical coherence tomography (OCT) is a new technology that uses near-infrared light in an interferometer to produce approximately 10-microns resolution cross-sectional images of the tissue of interest. The authors performed repeated quantitative assessment of nerve fiber layer thickness in individuals with normal and glaucomatous eyes, and they evaluated the reproducibility of these measurements. METHODS: The authors studied 21 eyes of 21 subjects by OCT. Each subject underwent five repetitions of a series of scans on five separate occasions within a 1-month period. Each series consisted of three circular scans around the optic nerve head (diameters, 2.9, 3.4, and 4.5 mm). Each series was performed separately using internal (fixation with same eye being studied) and external (fixation with contralateral eye) fixation techniques. The eye studied and the sequence of testing were assigned randomly. RESULTS: Internal fixation (IF), in general, provides a slightly higher degree of reproducibility than external fixation (EF). Reproducibility was better in a given eye on a given visit than from visit to visit. Reproducibility as measured by intraclass correlation coefficients were as follows: circle diameter (CD), 2.9 mm, 0.51/0.57 (normal/glaucoma) (IF), 0.43/0.54 (EF); CD, 3.4 mm, 0.56/0.52 (IF), 0.43/0.61 (EF); CD, 4.5 mm, 0.53/0.43 (IF), 0.42/0.49 (EF). CONCLUSIONS: Nerve fiber layer thickness can be reproducibly measured using OCT. Internal is superior to external fixation; each circle diameter tested provides adequate reproducibility.

We have recently developed new techniques for culturing chronic lymphocytic leukemia (CLL) lymphocytes from human aqueous humor. We used leukemic lymphocytes collected from the aqueous humor of a patient with CLL and leukemic glaucoma. We grew these leukemic cells in combination with a feeder cell layer and other technical refinements. Microscopy and immunoassay indicate success in obtaining a homogenous population of B-type CLL cells through the 12th passage of the culture. No significant effect on cell growth was found with either of two mitogens (PWM and PHA), or between culture with and without autologous serum. Our new techniques for culturing leukemic cells derived from the aqueous humor provide a reliable resource for the study of chronic lymphocytic leukemia lymphocytes and leukemic glaucoma.

The purpose of this study was to investigate the mechanisms of the leukemic glaucoma. We established a cell culture from leukemic cells collected from the aqueous humor of a living patient with chronic lymphocytic leukemia (CLL) and glaucoma secondary to the leukemia. We then perfused 16 pairs of fresh cadaver normal human eyes at a constant pressure of 10 mmHg at 37 degrees C. We delivered as a bolus either cultured CLL cells or cultured normal lymphocytes, using 3 x 10(2), 3 x 10(3), 3 x 10(4) or 3 x 10(5) cells in Bárány's solution, into one eye of each pair. The other eye of the pair served as a control, receiving a sham bolus of Bárány's solution alone. In addition, CLL and normal lymphocytes were perfused through 0.2, 0.6, 2, and 3 microns millipore filters. Following perfusion, the tissue and the filters were examined histopathologically by light, transmission and scanning electron microscopy. Cultured leukemic lymphocytes perfused into normal cadaver eyes caused a significantly more profound reduction in outflow facility than normal lymphocytes (P < 0.05); however, there was no significant difference in the effect on outflow facility between leukemic and normal lymphocytes when they were perfused through the millipore filters. Histopathology confirmed the presence of lymphocytes in the trabecular meshwork and Schlemm's canal, deforming on passage through the inner wall. Our results suggest that leukemic lymphocytes in CLL may reduce outflow facility by means of a biological interaction with the tissues of the outflow pathways, rather than by mechanical obstruction due to a lack of distensibility. Questions remain as to the nature of this biological interaction.