Disability Glare in the Aging Eye. Assessment and Impact on Driving☆

Purpose

To compare different methods for the assessment of disability glare sensitivity in the elderly, to arrive at an objective assessment of the condition of the eye. To delineate the importance of straylight values in vision.

Methods

Three groups of subjects were studied: 1) Young subjects without any eye disease, 2) elderly subjects without any eye disease and 3) elderly subjects with (early) cataract in at least one eye. All subjects underwent 2 glare tests, 2 straylight tests, ETDRS visual acuity test, Pelli Robson contrast sensitivity test, refraction, LOCS III cataract classification. Straylight was quantified by means of the straylight parameter s.

Results

Repeatability, discriminative ability, and added value as compared to visual acuity were low for the glare tests and good for the straylight measurements. For young normal subjects, with log(s)=0.9, the standard glare situation with low beams gives a contrast reduction of 1.3, whereas for the healthy 77 year olds this increases to 2. With cataract hardly affecting visual acuity, log(s) can be as high as 1.8, resulting in a contrast reduction of 3.4.

Conclusion

Straylight measurement is of relevance for the assessment of the glare-related hindrance during driving, and can be used to objectify complaints and aid in the decision-making regarding cataract surgery.

Measurement of stray light and glare: comparison of Nyktotest, Mesotest, stray light meter, and computer implemented stray light meter

AIM

To evaluate the properties of devices for measuring stray light and glare: the Nyktotest, Mesotest, "conventional" stray light meter and a new, computer implemented version of the stray light meter.

METHODS

112 subjects, divided in three groups: (1) young subjects without any eye disease; (2) elderly subjects without any eye disease, and (3) subjects with (early) cataract in at least one eye. All subjects underwent a battery of glare and stray light tests, measurement of visual acuity, contrast sensitivity, refraction, and LOCS III cataract classification. Subjects answered a questionnaire on perceived disability during driving.

RESULTS

Repeatability values were similar for all glare/stray light tests. Validity (correlation with LOCS III and questionnaire scores), discriminative ability (ability to discriminate between the three groups), and added value (to measurement of visual acuity and contrast sensitivity) were all superior for both stray light meters. Results of successive measurements are interrelated for the conventional but not the new stray light meter. This indicates a better resistance to fraud for the latter device.

CONCLUSIONS

The new computer implemented stray light meter is the most promising device for future stray light measurements.

Multifocal oscillatory potentials in CSNB1 and CSNB2 type congenital stationary night blindness

We evaluated the function of the inner retina in patients with congenital stationary night blindness of the complete (CSNB1) and the incomplete type (CSNB2) by recording multifocal oscillatory potentials (mf-OPs). The VERIS system was used to record mf-OPs from 61 areas of the central retina from 5 CSNB1 patients (4 with NYX gene mutation), 6 CSNB2 patients (2 with CACNA1F mutation) and 11 control subjects. For each subject group, the first- and second-order kernel responses for one eye were analysed and the amplitudes and implicit times of their major components compared to 5 concentric rings centred on the fovea. In CSNB1 patients, the mf-OP peak amplitudes of the first-order kernel responses showed a significant reduction of the first peak without significant reduction of the second, whereas in CSNB2 both peak amplitudes were barely discernable from noise for all eccentricities. In the second-order kernel, the third peak was reduced in CSNB1 patients, and again not discernable from noise in CSNB2 patients. The difference in amplitude between the control and CSNB1 groups was significant for the late components of the first- and the second-order kernel. Implicit times were not significantly altered. The difference in mf-OP amplitude between CSNB1 and CSNB2 patients reflects the different molecular mechanisms underlying the two types of disease, which differentially affect the postreceptoral pathways of cone signal processing. The well-preserved peak 2 amplitudes of first-order mf-OPs and peak 3 amplitudes of second-order mf-OPs in CSNB1 patients point to a major impact of OFF-pathway components on these responses which are not present in CSNB2 patients. In conclusion, our results show that CSNB1 and CSNB2 are two different types of disease, not only on a genetic but also on a pathophysiological level.

Evaluation of Murex CMV DNA hybrid capture assay for detection and quantitation of cytomegalovirus infection in patients following allogeneic stem cell transplantation

Murex hybrid capture DNA assay (HCS) is a solution hybridization antibody capture assay for detection and quantitation of cytomegalovirus (CMV) DNA in leukocytes. To determine whether CMV HCS is sensitive enough to initiate and monitor antiviral therapy after allogeneic stem cell transplantation (SCT), 51 consecutive SCT recipients were prospectively screened for the appearance of CMV infection by HCS, PCR, and culture assays from blood samples. Preemptive antiviral therapy was initiated after the second positive PCR result in all patients, as previously reported, and HCS was not considered for clinical decision making. A total of 417 samples were analyzed. Of these, 21 samples were found to be positive by PCR and HCS, 88 samples were PCR positive but HCS negative, and 308 were negative by both assays. Concordance of results between PCR and HCS and between HCS and blood culture was observed in 78.9 and 95.9% of the samples assayed, respectively. PCR was found to be more sensitive than HCS, and HCS was more sensitive than the blood culture assay (P < 0.0001). Four patients with symptomatic CMV infection were PCR positive prior to the onset of CMV-related symptoms, whereas HCS detected CMV DNA in three patients prior to and one at onset of CMV disease. The numbers of genomes per milliliter of blood were higher in patients with symptomatic CMV infection than in those with asymptomatic CMV infection (P = 0.06). None of the HCS-negative patients developed CMV disease. Thus, all patients with CMV disease were correctly identified by HCS; however, the lower sensitivity limit of the HCS assay may still be insufficient to allow diagnosis of CMV infection early enough to prevent CMV disease in patients following allogeneic SCT.