Lens Opacities Classification System III: cataract grading variability between junior and senior staff at a Singapore hospital.
ABSTRACT To test the reliability of the Lens Opacities Classification System III (LOCS III) cataract grading between observers at different levels of ophthalmology experience.
Ophthalmology Department, National University Hospital, Singapore, Singapore.
In this comparative study, a non-ophthalmology trainee, a basic ophthalmology trainee, and an ophthalmology consultant graded cataracts in 28 patients preoperatively. The observers had a meeting to discuss their interpretations of the LOCS III manual to standardize the grading system and then graded 37 additional patients.
There was a statistically significant increase in inter-observer agreement in all 3 LOCS III categories after standardization of the LOCS III system. The kappa values after standardization fell in the moderate (0.41 to 0.60) to substantial (0.61 to 0.80) range. There was no statistically significant relationship between the observer's experience and the kappa values.
There was an increase in inter-observer agreement in all categories after standardization between operators.
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Conference Proceeding: Ultrasound Techniques for Lens Hardness Characterization: A comparison Study[show abstract] [hide abstract]
ABSTRACT: Cataract affects more than 20 million people worldwide and is the leading cause of vision loss. Currently, the phacoemulsification is the most used procedure to extract cataract and recover visual acuity. Optimal phacoemulsification energy is demanded for safety cataract removal. It is well established that the energy value is determined by the cataract hardness. In this study twenty porcine eyes were used as experimental samples. Cataract was induced by an ethanol:2-propanol:formalin solution. A 25 MHz focused transducer has been used to estimate the ultrasound velocity and attenuation. Statistical analysis was performed to compare the different used methodologies and to correlate the different ultrasound parameters with different stages of cataract formation (lens hardness).Ultrasonics Symposium (IUS), 2012 IEEE International; 10/2012
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ABSTRACT: To calculate the average lens density (ALD) and nuclear lens density (NLD) using Scheimpflug images and to determine their correlation with logarithmic minimal angle resolution (logMAR) best-corrected visual acuity (BCVA), contrast sensitivity (CS), and lens grading based on the Lens Opacities Classification System (LOCS) III. Cross-sectional observational study. One hundred ten patients with age-related nuclear cataract. The logMAR BCVA was recorded using Early Treatment Diabetic Retinopathy Study charts and photopic contrast-sensitivity using CSV-1000LV (Vector Vision, Greeneville, OH). Fifty Scheimpflug images (Pentacam, Oculus, Germany) covering 360 degrees of the lens were obtained for 1 eye of each patient after dilation. All Scheimpflug images were exported to ImageJ software (NIH, Bethesda, MD) for analysis wherein the ALD and NLD (using a mask applied to the lens nuclear area) were calculated in pixel-intensity units. Repeatability was determined using coefficient of variation (CoV) and intraclass correlation coefficient (ICC). Lens opacity on slit-lamp images was graded using LOCS III for nuclear opalescence (NO) and nuclear color (NC). We evaluated ALD and NLD on Scheimpflug images and their correlation with NO and NC LOCS III grading, BCVA, and photopic CS. The ICC for ALD and NLD were 0.983 and 0.99, respectively; the CoV were 3.92+/-1.76% and 2.57+/-0.74%, respectively. The ALD correlated with NO (r = .774; P<0.001), NC (r = .732; P<0.001), BCVA (r = 0.696; P<0.001), and CS at 3 cycles per degree CPD (P = 0.011), 6, 12, and 18 CPD (P<0.001). The NLD correlated with NO (r = .859; P<0.001), NC (r = .81; P<0.001), BCVA (r = .760; P<0.001), CS at 3 CPD (P = 0.002), 6, 12, and 18 CPD (P<0.001). The NLD had a significantly stronger correlation with BCVA (P<0.05), NO (P<0.01), NC (P<0.01), and CS at 6 CPD (P<0.01) and 12 CPD (P<0.005) compared with ALD. Repeatable 360 degrees lens density measurements were obtained using Scheimpflug imaging. A stronger correlation was observed between NLD and LOCS III grading, BCVA, and photopic CS than with ALD. The NLD is an objective and repeatable method for assessment of lens density, which could be helpful in longitudinal studies monitoring nuclear cataracts.Ophthalmology 06/2009; 116(8):1436-43. · 5.56 Impact Factor
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ABSTRACT: The lens of the eye is recognized as one of the most radiosensitive tissues in the human body, and it is known that cataracts can be induced by acute doses of less than 2 Gy of low-LET ionizing radiation and less than 5 Gy of protracted radiation. Although much work has been carried out in this area, the exact mechanisms of radiation cataractogenesis are still not fully understood. In particular, the question of the threshold dose for cataract development is not resolved. Cataracts have been classified as a deterministic effect of radiation exposure with a threshold of approximately 2 Gy. Here we review the combined results of recent mechanistic and human studies regarding induction of cataracts by ionizing radiation. These studies indicate that the threshold for cataract development is certainly less than was previously estimated, of the order of 0.5 Gy, or that radiation cataractogenesis may in fact be more accurately described by a linear, no-threshold model.Radiation Research 08/2009; 172(1):1-9. · 2.70 Impact Factor