Comparative analysis of circulating endothelial progenitor cells in age-related macular degeneration patients using automated rare cell analysis (ARCA) and fluorescence activated cell sorting (FACS).

BACKGROUND: Patients with age-related macular degeneration (ARMD) begin with non-neovascular (NNV) phenotypes usually associated with good vision. Approximately 20% of NNV-ARMD patients will convert to vision debilitating neovascular (NV) ARMD, but precise timing of this event is unknown. Developing a clinical test predicting impending conversion to NV-ARMD is necessary to prevent vision loss. Endothelial progenitor cells (EPCs), defined as CD34(+)VEGR2(+) using traditional fluorescence activated cell sorting (FACS), are rare cell populations known to be elevated in patients with NV-ARMD compared to NNV-ARMD. FACS has high inter-observer variability and subjectivity when measuring rare cell populations precluding development into a diagnostic test. We hypothesized that automated rare cell analysis (ARCA), a validated and FDA-approved technology for reproducible rare cell identification, can enumerate EPCs in ARMD patients more reliably. This pilot study serves as the first step in developing methods for reproducibly predicting ARMD phenotype conversion. METHODS: We obtained peripheral venous blood samples in 23 subjects with NNV-ARMD or treatment naïve NV-ARMD. Strict criteria were used to exclude subjects with known angiogenic diseases to minimize confounding results. Blood samples were analyzed in masked fashion in two separate laboratories. EPCs were independently enumerated using ARCA and FACS within 24 hours of blood sample collection, and p<0.2 was considered indicative of a trend for this proof of concept study, while statistical significance was established at 0.05. RESULTS: We measured levels of CD34(+)VEGFR2(+) EPCs suggestive of a trend with higher values in patients with NV compared to NNV-ARMD (p = 0.17) using ARCA. Interestingly, CD34(+)VEGR2(+) EPC analysis using FACS did not produce similar results (p = 0.94). CONCLUSIONS: CD34(+)VEGR2(+) may have predictive value for EPC enumeration in future ARCA studies. EPC measurements in a small sample size were suggestive of a trend in ARMD using ARCA but not FACS. ARCA could be a helpful tool for developing a predictive test for ARMD phenotype conversion.

Treatment of neovascular age-related macular degeneration with intravitreal bevacizumab: efficacy of three consecutive monthly injections.

PURPOSE: To report the efficacy of treatment of neovascular age-related macular degeneration (AMD) with intravitreal bevacizumab (Avastin; Genentech, Inc, South San Francisco, California, USA) when administered in a series of three monthly injections followed by a period of observation. DESIGN: Retrospective case series. METHODS: Retrospective review of consecutive eyes with all choroidal neovascular lesion subtypes resulting from neovascular AMD treated with intravitreal bevacizumab. Treatment consisted of a pars plana injection of 1.25 mg Avastin (0.05 ml bevacizumab at a concentration of 25 mg/ml). Evaluation consisted of a complete ophthalmologic examination, including best-corrected visual acuity (VA) measurement, ophthalmoscopy, and optical coherence tomography. Eyes received a series of three monthly injections followed by a three-month period of observation. RESULTS: A total of 36 patients (37 eyes) received a series of three consecutive monthly intravitreal injections of bevacizumab. Twenty (54%) of 37 eyes had no previous treatments for neovascular AMD in the eye that received bevacizumab. Seventeen (46%) of 37 eyes had received some previous treatment before initiation of bevacizumab therapy. Intravitreal Avastin therapy produced an improvement in foveal thickness over time in eyes with neovascular AMD. This improvement was sustained during the series of three monthly injections. All eyes experienced worsening after three months without treatment. No statistically significant effect on VA was demonstrated in this series. CONCLUSION: Intravitreal bevacizumab therapy produced an improvement in foveal thickness over time in eyes with neovascular AMD when one injection was given each month for three consecutive months. All eyes experienced increased foveal thickening during the subsequent three months without treatment.

Three-dimensional non-coplanar conformal radiotherapy yields better results than traditional beam arrangements for adjuvant treatment of gastric cancer.

PURPOSE: The current standard of adjuvant treatment for gastric cancer after curative resection is concurrent administration of radiotherapy and 5-fluorouracil-based chemotherapy. The radiation fields are often arranged as anterioposterior-posteroanterior opposed parallel fields with general recommendations for sparing at least two-thirds of one kidney. We investigated whether a better radiation distribution would be achievable with three-dimensional conformal approaches compared with the classic anterioposterior-posteroanterior fields. METHODS AND MATERIALS: A total of 19 patients with adenocarcinoma of the stomach were treated with adjuvant chemoradiotherapy using a non-coplanar four-field arrangement. In each case, parallel planning using an anterioposterior-posteroanterior arrangement and a four-field "box" was performed, and the generated plans were subsequently compared for coverage of target volumes and doses to irradiated organs next to the tumor bed. A separate analysis was performed for kidneys exposed to greater and lower doses in each patient. The mean radiation dose and percentage of kidney volume receiving a dose >20 Gy were registered. Statistical analysis was performed using the two-tailed t test. RESULTS: The clinical target volume was adequately covered in all three plans. In the greater-dose kidney group, all the differences were statistically significant with a benefit for the three-dimensional plan. In the lower-dose kidney group, the differences in the mean radiation dose did not reach the level of statistical significance, and the differences in the kidney volume receiving a dose >20 Gy showed a statistically significant benefit for the three-dimensional plan. CONCLUSION: Non-coplanar three-dimensional-based conformal planning for postoperative radiotherapy for gastric cancer provided the best results regarding kidney and spinal cord exposure with adequate clinical target volume coverage. This technique was readily implemented in clinical practice.

Introducing a new computer-based test for the clinical evaluation of color discrimination.

PURPOSE: To evaluate the Portal color sort test (PCST), a new computer-based test of color vision, by comparing it with a series of clinical tests of color vision in normal and color deficient subjects. DESIGN: Prospective clinical laboratory study. METHODS: Fifty-nine subjects with normal trichromatic vision or with congenital color vision defects underwent a series of color vision tests that included the 15-plate Ishihara test, the D-15 Farnsworth-Munsell test (D-15), the Farnsworth-Munsell 100-Hue test (FM 100-Hue), and the PCST under rigorous standardized conditions, as recommended by the respective manufacturers. The PCST generates a numerical discrimination score comparable to the FM 100-Hue. RESULTS: To test validity, discrimination scores generated by the PCST were compared with scores on the FM 100-Hue. The Spearman rank correlation between discrimination scores on the FM 100-Hue and the PCST was 0.8 (P < .001). Reliability was assessed by asking patients to retake the PCST at a later sitting. Patients retaking the PCST achieved similar scores on their second sitting as on the first. The correlation in the score between the two tests was 0.7 (95% confidence interval [CI]: 0.4-0.9, P < .001). Median (quartiles) time to complete the PCST was 3.1 minutes. This was faster than the FM 100-Hue time (P < .001), but slower than both the Ishihara and the D-15 (both P < .001). CONCLUSIONS: This study suggests that the PCST, a test of color vision deficiency, can be used effectively and reliably as a tool for screening (comparable to the Ishihara plates and the D-15) and grading (comparable to the FM 100-Hue) color discrimination ability.

Comatic aberration as a cause of monocular diplopia.

Three patients (5 eyes) presented with complaints of monocular diplopia and no history of ocular trauma or surgery. The patients had comprehensive neuroophthalmic evaluation including manifest refraction, anterior segment and dilated fundus examination, and corneal topography. All patients also had wavefront analysis using the LADARWave system (Alcon). Two patients (4 eyes) also had hard contact lens overrefraction. The patients had a normal initial examination including corneal topography. One patient (2 eyes) did not experience resolution of diplopia with pinhole. No eye improved with manifest refraction or hard contact lens overrefraction. However, each patient had a significant amount of coma on wavefront analysis. Moreover, eyes with horizontal diplopia had horizontal coma and eyes with vertical diplopia had vertical coma as measured with the wavefront device. Higher-order optical aberrations such as coma may be associated with monocular diplopia. Wavefront technology may be useful in the workup of monocular diplopia.

Retinoblastoma.

Retinoblastoma, a neuroblastic tumor, is the most common primary intraocular malignancy of childhood. Patients usually present with leukokoria (white reflex or white pupil), detected in primary care. The mean age at diagnosis is 12 months for bilateral tumors and 24 months for unilateral tumors. If untreated, almost all patients die of intracranial extension and disseminated disease within two years. However, new diagnostic and treatment methods allow for a high cure rate (93 percent five-year survival in the United States), therefore it is important that primary care physicians recognize the manifestations of this malignancy. Diagnosis is primarily by history and complete ophthalmic examination, with studies including ultrasonography of the eye and imaging of the orbits and brain. Treatment modalities include laser thermotherapy, cryotherapy, radioactive plaques, external beam radiotherapy, chemotherapy, and enucleation. Prospective parents with a family history of retinoblastoma should be referred for genetic counseling. Office evaluation for a red reflex in children should be performed until three years of age. If leukokoria is observed, the patient should be examined by an ophthalmologist within one week.

Color vision testing.

The science of color vision testing has evolved since its inception in the late 1700s. Since then, the rudimentary technique of comparing color names has been replaced by more sophisticated methods. Commonly used tests in clinical practice today include isochromatic plates, arrangement tests, anomaloscopes, and lantern tests. Each category has unique attributes that make it suitable for a particular clinical situation. The clinician should be aware of the requirements for administering and grading each test type. Factors such as the quality of the illuminant and the size of the field of view are important elements in setting up a proper color vision laboratory. Currently, no treatment exists for congenital color vision defects. However, studies show that diagnosis of these defects early in life may help children adjust better to tasks at school and may help adults understand their limitations at work. Acquired color vision defects are often used as markers of ocular pathology in the clinical setting. Different color vision tests are appropriate for diagnosing the different categories of defects. Sometimes, a battery of tests may be appropriate. This paper is a review of the current knowledge in the field of color vision testing.

Ocular ethambutol toxicity.

Ethambutol is an antimicrobial agent used frequently to treat tuberculosis. The most commonly recognized toxic effect of ethambutol is optic neuropathy, which generally is considered uncommon and reversible in medical literature. We describe a 43-year-old man who developed signs and symptoms of bilateral optic neuropathy during treatment with ethambutol. This case and a review of the literature show the severe and unpredictable nature of ethambutol toxicity and its potential for irreversible vision loss despite careful ophthalmologic monitoring.