Self-assessment of the quality of vision: association of questionnaire score with objective clinical tests.

PURPOSE: To investigate the association of a quality of life-visual function questionnaire with an objective clinical test of visual function. METHODS: We have developed a questionnaire to assess self-reported visual satisfaction in ophthalmic patients suffering from chronic eye conditions causing visual impairment. The questionnaire was administered to 120 patients suffering from age-related cataract, chronic open angle glaucoma, age-related macular degeneration, branch retinal vein occlusion, and presbyopia or minor refractive defects. All the participants also underwent determination of visual acuity, contrast sensitivity, glare, and visual field. RESULTS: The questionnaire has a good reproducibility, a high internal consistency, and is able to discriminate between the different groups of patients. The total questionnaire score is significantly associated with the results of all visual function tests with the exception of glare. When entered into a multiple linear regression model, near visual acuity and contrast sensitivity are still considerably associated with the total questionnaire score. The psychological attitude of the patient towards his/her health problem is also associated with the total average score. CONCLUSIONS: Overall, the model explains 49% of the variance in the average questionnaire score.

An independent evaluation of the Age-Related Eye Disease Study (AREDS) cataract grading system.

PURPOSE: To assess intra- and interobserver reproducibility of the Age-Related Eye Disease Study (AREDS) system for grading lens opacities and to provide data on its capacity to reliably detect changes in lens status. METHODS: Independent and replicate grading of 40 sets of lens photographs (one slit-lamp and two retroillumination photographs) were performed by three experienced observers. Patients were participants in the Collaborative Italian-American Clinical Trial of Nutritional Supplements which is testing the effect of a mineral-multivitamin supplement on age-related cataract (CTNS). Scatterplots and intraclass correlation were used to assess measurement error. RESULTS: Analysis revealed good intra- and interobserver reproducibility of the system. Greatest intraobserver measurement error showed 100% of pairs within 10% areal difference for cortical cataract, 97.5% within 15% areal difference for posterior subcapsular cataract, and 100% within 1 density unit difference for nuclear opacity. Greatest interobserver measurement error showed 95% of pairs within 10% areal difference for cortical cataract, 97.5% within 15% areal difference for posterior subcapsular cataract, and 97.5% within 1.5 density unit difference for nuclear opacity. CONCLUSIONS: The AREDS lens opacities grading system appears to be sufficiently reliable to detect changes of at least 10% areal involvement for cortical, 15% areal involvement for posterior subcapsular, and 1.0 units for nuclear opacities. It therefore seems sufficiently sensitive to adequately monitor progression of lens opacities in a longitudinal study of patients with early cataract. Its applicability in a population with advanced or complex mixed opacities must await further testing.

The Topcon SP 1000 and Image-NET systems. A comparison of four methods for evaluating corneal endothelial cell density.

The objective of this study was to compare four methods of counting corneal endothelial cell density using the Topcon SP 1000 microscope and Image-NET digital graphic software. Two independent observers quantified cell density from 63 endothelial photomicrographs using the various standardized techniques. The first method was that suggested for use with Topcon SP 1000, employing five different reference grids to compare subjectively with the endothelial cell density of the unknown sample. The other three methods involved the automated, semiautomated, and manual procedures developed for use with the Image-NET system software. The manual Image-NET system is presently considered to yield accurate cell morphology data. Confidence limits and standard errors of mean differences between values obtained by different methods were used to evaluate agreement and reproducibility of computerized methods. Sensitivity and specificity were calculated for two different threshold limits of endothelial cell density. Results showed that the automated Image-NET system is not reliable for clinical use because of its poor agreement with other methods and its lack of sensitivity and specificity at the selected threshold limits of endothelial cell density. The comparative Topcon method of using reference grids, although inexpensive and accurate for 500 cell/mm2 increments, was considered too imprecise for most clinical situations. The semiautomated Image-NET system, in half the analysis time required by the manual method, provided endothelial cell count estimates that were not clinically different from those obtained with manual counting.

Decrease of intraocular pressure after subconjunctival injection of mitomycin in human glaucoma.

OBJECTIVE: To investigate the effects of a subconjunctival injection of mitomycin on the intraocular pressure in human eyes affected by glaucoma. DESIGN: Consecutive case series, prospective study, intraocular pairwise comparison (paired samples Student's t test adopted). SETTING: Hospital-based glaucoma clinic. PATIENTS: Twelve consecutive patients with bilateral glaucoma and monolateral blindness, intraocular pressure greater than 30 mm Hg in the blind eye (mean of the two highest values of the diurnal curve, confirmed at 96-hour interval), and no previous bulbar surgery. INTERVENTION: Subconjunctival injection of 0.5 mL of 0.2% mitomycin in the upper temporal quadrant, preceded and followed by treatment with topical indomethacin. MAIN OUTCOME MEASURE: Analysis of the variance of the mean intraocular pressure before and after the injection of mitomycin in each eligible eye. RESULTS: An intraocular pressure decrease was observed in each eligible eye the day after the treatment (mean [+/- SD] decrease, 7.15 +/- 1.46 mm Hg). The effect was still detectable at the end of the 60 days of follow-up (mean [+/- SD] decrease, 5.67 +/- 1.61 mm Hg). No change of intraocular pressure, in the meantime, was observed in the fellow eye. CONCLUSIONS: Topically applied mitomycin induces a decrease of intraocular pressure in human glaucomatous eyes. Our data confirm previous results obtained in albino rabbits and support the hypothesis that mitomycin exerts a still unknown direct effect on aqueous humor dynamics in the eye.