Evaluation of contrast sensitivity in patients with advanced glaucoma: comparison of two tests

Comparison of the Circumpapillary Structure-Function and Vasculature-Function Relationships at Different Glaucoma Stages Using Longitudinal Data

Purpose

This study investigated the global and regional correlations between longitudinal structure-function (S-F) and vasculature-function (V-F) data using circumpapillary retinal nerve fiber layer thickness (cpRNFLT) measurements from optical coherence tomography (OCT), circumpapillary vessel density (cpVD) from OCT angiography (OCTA), and the corresponding visual field mean sensitivities at different glaucoma stages.

Methods

A total of 107 eyes from 107 glaucoma patients with progressive visual field (VF) changes followed up for an average of 3.33 ± 1.39 years were enrolled, including early-to-moderate (51 eyes) and advanced (56 eyes) stages. The rates of longitudinal change in the VF mean deviation (MD), cpRNFLT, and cpVD were evaluated using linear mixed-effects models and compared between different glaucoma stages. Longitudinal global and regional S-F and V-F relationships were assessed by repeated measures correlation analysis by glaucoma stage.

Results

No significant differences were found in the rates of VF MD and cpVD changes (P > 0.05) between the two glaucoma stage groups. CpRNFLT decreased more rapidly in the early-to-moderate stage group (P < 0.001) in which significant longitudinal global and regional correlations were found in both S-F and V-F relationships (all P < 0.05), except for the nasal sector. Significant global and regional correlations were only found in V-F relationship in advanced stage cases (all P < 0.05).

Conclusions

Significant longitudinal V-F relationships exist globally and regionally regardless of glaucoma stage but no longitudinal S-F relationship is present in advanced glaucoma. Longitudinal follow-up of cpVD parameters may be useful for monitoring glaucomatous VF progression at all disease stages.

Association of macular structure, function, and vessel density with foveal threshold in advanced glaucoma

Identifying new biomarkers associated with central visual function impairment is important in advanced glaucoma patients. This retrospective cross-sectional study enrolled 154 eyes from 154 subjects, consisting of 86 patients with advanced open-angle glaucoma (mean deviation of 24-2 visual field [VF] tests < - 15 dB) and 68 healthy controls. Structure, function, and vessel density (VD) parameters were obtained using optical coherence tomography (OCT), 24-2 standard automated perimetry, and OCT angiography, respectively. The relationships of macular thickness, central 5° and 10° VF mean sensitivity (MS), and macular VD parameters with foveal threshold (FT), representing central visual function, were investigated using partial correlation analyses and linear regression analyses, with age adjustment. Superficial and deep layer macular VD, central 5° and 10° VF MS, and best corrected visual acuity (BCVA) correlated significantly with FT after age adjustment (P < 0.05). In multivariate linear regression analyses, FT associated significantly with BCVA (β = - 8.80, P < 0.001), central 5° MS (β = 0.30, P = 0.037), and deep-layer global parafoveal VD (β = 0.37, P = 0.037). Thus, deep-layer parafoveal VD is an independent predictor of FT and may be a potential biomarker for central visual function in advanced glaucoma.

Changes in contrast sensitivity after surgery for intermittent exotropia

To determine whether intermittent exotropia (IXT) surgery affects contrast sensitivity (CS), this retrospective study evaluated the changes in monocular and binocular CS and the binocular summation ratio (BSR) quantified as the ratio between the values of the binocular and the better monocular CS score (BSR = binocular CS score/better monocular CS score) after surgery for IXT. The subjects were patients who had undergone IXT-correcting surgery with a postoperative follow-up of > 3 months and had pre- and postoperative records of Mars CS test scores. In total, 64 patients (128 eyes) were evaluated. Both the binocular and monocular CS scores of the operated eyes were significantly worse on postoperative 1 day than the preoperative scores, but they were recovered after 1 week. The monocular CS scores of the operated eyes were significantly worse than those of the non-operated eyes until 1 week. There was no significant difference in monocular CS scores between the one-muscle and two-muscle surgeries and in binocular CS scores between the successful alignment and overcorrection groups even on the first day after surgery. The mean BSR was significantly decreased until postoperative month 1, however, recovered to preoperative levels after month 3. In conclusion, IXT-correcting surgery may temporarily worsen the CS, but it is recovered to preoperative levels. Thus, changes in CS in the immediate postoperative period after strabismus surgery should not be of concern.

Evaluation of the association between macular damage and disability glare in patients with advanced glaucoma

PURPOSE

This study aimed to investigate the factors associated with disability glare in patients with advanced glaucoma and evaluate the impact of disability glare on the vision-related quality of life.

METHODS

We prospectively studied 225 eyes (225 patients) with advanced glaucoma. The visual function was evaluated using the 10-2 and 24-2 Humphrey visual field (VF) (Dublin, California) and contrast sensitivity test. Structural parameters were obtained using RTVue optical coherence tomography and angiography (Fremont, California). Significant loss of macular vessel density (mVD) was defined as VD < 30%. Each participant completed the National Eye Institute Visual Function Questionnaire 25 (NEI-VFQ-25) and questions regarding subjective symptoms of glare.

RESULTS

Fifty-six patients (24.9%) experienced glare and had a lower NEI-VFQ-25 composite score (P = 0.017). The average retinal nerve fiber layer and ganglion cell complex thickness and mean deviation (MD) in the 24-2 VF test were not associated with glare. Significant superior or inferior mVD loss (P < 0.001; odds ratio [OR], 3.45; and 95% confidence interval [CI], 1.83-6.55), lower logarithmic contrast sensitivity at 0.75 cycles/degree (P < 0.001; OR, 0.27; and 95% CI, 0.13-0.56), and worse MD in the 10-2 VF test (P < 0.001; OR, 0.93; and 95% CI, 0.89-0.97) showed an association with glare.

CONCLUSION

In advanced glaucoma, central VF defect and mVD loss are associated with disability glare, which negatively impacts vision-related quality of life.

Aging effects on contrast sensitivity in visual pathways: A pilot study on flicker adaptation

Contrast sensitivity is reduced in older adults and is often measured at an overall perceptual level. Recent human psychophysical studies have provided paradigms to measure contrast sensitivity independently in the magnocellular (MC) and parvocellular (PC) visual pathways and have reported desensitization in the MC pathway after flicker adaptation. The current study investigates the influence of aging on contrast sensitivity and on the desensitization effect in the two visual pathways. The steady- and pulsed-pedestal paradigms were used to measure contrast sensitivity under two adaptation conditions in 45 observers. In the non-flicker adaptation condition, observers adapted to a pedestal array of four 1°×1° squares presented with a steady luminance; in the flicker adaptation condition, observers adapted to a square-wave modulated luminance flicker of 7.5 Hz and 50% contrast. Results showed significant age-related contrast sensitivity reductions in the MC and PC pathways, with a significantly larger decrease of contrast sensitivity for individuals older than 50 years of age in the MC pathway but not in the PC pathway. These results are consistent with the hypothesis that sensitivity reduction observed at the overall perceptual level likely comes from both the MC and PC visual pathways, with a more dramatic reduction resulting from the MC pathway for adults >50 years of age. In addition, a similar desensitization effect from flicker adaptation was observed in the MC pathway for all ages, which suggests that aging may not affect the process of visual adaptation to rapid luminance flicker.

Interventions to Improve Reading Performance in Glaucoma

PURPOSE

To evaluate whether changes to contrast, line spacing, or font size can improve reading performance in patients with glaucoma.

DESIGN

Cross-sectional study.

PARTICIPANTS

Thirty-five patients with glaucoma and 32 healthy control participants.

METHODS

A comprehensive ophthalmologic examination was performed followed by reading speed assessment using the Minnesota Low Vision Reading (MNREAD) test under a range of contrasts (10%, 20%, 30%, 40%, and 50%), line spacings (1.0, 1.5, 2.0, 2.5, and 3.0 lines), and font sizes (0.8, 0.9, 1.0, 1.1, and 1.2 logarithm of the minimum angle of resolution), for a total of 15 tests. Regression analyses were performed to examine the effect of varying test conditions on reading speed (measured in words per minute [wpm]).

RESULTS

Participants' mean age was 63.0 ± 12.6 years. Patients with glaucoma showed a visual field mean deviation in the better eye of -6.29 ± 6.35 dB. Reading speeds were significantly slower in patients with glaucoma versus control participants for 14 of the 15 MNREAD tests, despite no significant differences in age, gender, or education between groups. Increased contrast (from 10% to 50%) was associated with faster reading speed in patients with glaucoma (10.6-wpm increase per 10% increase in contrast; 95% confidence interval, 7.4-13.8 wpm; P < 0.001; R² = 0.211). No significant improvement was found in reading speed with increase in font size or line spacing.

CONCLUSIONS

Patients with glaucoma showed significantly slower reading speeds than similarly aged control participants. Reading speed was improved by increasing contrast, but not by increases in line spacing or font size.

Assessing glaucoma deterioration using Spaeth/Richman contrast sensitivity test

Purpose:

To assess changes in the central and peripheral contrast sensitivity in severe primary open-angle glaucoma (POAG) patients using a computer-based Spaeth/Richman contrast sensitivity test (SPARCS) over a period of 24 months.

Methods:

Our pilot, observational study included 15 patients (30 eyes) with severe POAG. Visual acuity, intraocular pressure, number of anti-glaucoma drugs, visual fields, and SPARCS score were recorded at first visit and at 12 and 24 months.

Results:

We observed changes in mean deviation (MD) from −19.37 ± 5.04 to −20.63 ± 4.07, mean pattern standard deviation (PSD) from 11.49 ± 2.61 to 11.35 ± 2.01, and mean SPARCS score from 54.97 ± 15.66 to 53.50 ± 16.42. We found no statistically significant difference between visual field parameters and SPARCS scores associated with the number or type of prescribed anti-glaucoma drugs. Spearman’s correlation coefficient of SPARCS at baseline (SPARCS1) versus MD at baseline (MD1) was 0.274 (p = 0.142) and SPARCS1 versus PSD at baseline (PSD1) was −0.163 (p = 0.389). The correlation coefficient between SPARCS at 12 months (SPARCS2) versus MD (MD2) at the same time point was computed to be 0.391 (p = 0.03), whereas SPARCS2 versus PSD at 12 months was −0.212 (p = 0.262). Similarly, we found the coefficient to be 0.336 (p = 0.069) for SPARCS3 (SPARCS at 24 months) versus MD3 (MD at 24 months) and −0.242 (p = 0.197) for SPARCS3 versus PSD3 (PSD at 24 months). Correlation coefficients between SPARCS1/2, SPARCS1/3, MD1/2, MD1/3 PSD1/2, and PSD1/3 were 0.856, 0.865, 0.748, 0.722, 0.497, and 0.562, respectively (p < 0.001). MD changed by 9.46% ± 12.73%, PSD by 0.64% ± 14.03%, and average SPARCS by 3.31% ± 12.73% over 24 months.

Conclusion:

The data from our study indicate the utilitarian application of SPARCS, an inexpensive and readily available tool for monitoring functional deterioration in cases with advanced glaucomatous damage, especially in resource-poor settings. Furthermore, it is a useful and reliable alternative to the imaging modalities where retinal nerve fiber layer measurement can be erroneous in advanced cases secondary to the floor effect.