Contrast Sensitivity and Glaucoma

Impact of Glaucomatous Ganglion Cell Damage on Central Visual Function

Glaucoma, a leading cause of irreversible blindness, is characterized by the progressive loss of retinal ganglion cells (RGCs) and subsequent visual field defects. RGCs, as the final output neurons of the retina, perform key computations underpinning human pattern vision, such as contrast coding. Conventionally, glaucoma has been associated with peripheral vision loss, and thus, relatively little attention has been paid to deficits in central vision. However, recent advancements in retinal imaging techniques have significantly bolstered research into glaucomatous damage of the macula, revealing that it is prevalent even in the early stages of glaucoma. Thus, it is an opportune time to explore how glaucomatous damage undermines the perceptual processes associated with central visual function. This review showcases recent studies addressing central dysfunction in the early and moderate stages of glaucoma. It further emphasizes the need to characterize glaucomatous damage in both central and peripheral vision, as they jointly affect an individual's everyday activities.

Contrast Sensitivity and Low Contrast Visual Acuity in Children With Normal Visual Acuity

PURPOSE

To measure and report the distribution of distance and near contrast sensitivity (CS) and low contrast visual acuity (LCVA) at 5% and 2.5% contrast in children aged 5-15 years with normal visual acuity (VA).

DESIGN

Prospective, cross-sectional study.

SETTING

Schools in Southern India.

STUDY POPULATION

One thousand fifty-two children aged 5 to 15 years (mean age 10.61 ± 2.85 years) with a presenting visual acuity of 0.00 logMAR or better in both eyes and a stereo acuity of 40 seconds of arc or better were recruited from nine schools. Repeatability of contrast sensitivity and low contrast visual acuities were tested in 246 children. Pelli-Robson charts were used to measure the distance and near contrast sensitivity at 1 m and 40 cm, respectively. The low contrast visual acuity was recorded at 5% and 2.5% contrast using LEA Symbols at 3 m.

RESULTS

Overall, the mean ± SD, (95% CI) monocular distance and near CS were 1.75 ± 0.11 (1.76-1.75) logCS and 1.72 ± 0.10 (1.73-1.71) logCS, respectively. The mean LCVA at 5% and 2.5% contrasts were 0.20 ± 0.10 (0.21-0.20) logMAR and 0.39 ± 0.11 (0.40-0.39) logMAR, respectively. Distance and near CS gradually improved till the ages of 11 and 13, respectively, and then plateaued. Similarly, LCVA at 5% and 2.5% contrasts gradually improved till age ten before plateauing. The Coefficient of Repeatability (CoR) for CS was ±0.02 logCS for distance, ±0.05 logCS for near, and ±0.01 logMAR for both LCVA contrasts.

CONCLUSIONS

The study provides age-specific normative values for distance and near CS, and LCVA in a cohort of children aged 5-15 years. These results are important to understand the impact of ocular conditions on CS in children and have utility in clinical evaluations.

Association between contrast sensitivity function and structural damage in primary open-angle glaucoma

AIMS

To evaluate the association between contrast sensitivity function (CSF) and glaucomatous structural damage in primary open-angle glaucoma (POAG).

METHODS

A cross-sectional study was performed with 103 patients (103 eyes) aged 25-50 years who had POAG without any other ocular disease. CSF measurements were obtained by the quick CSF method, a novel active learning algorithm that covers 19 spatial frequencies and 128 contrast levels. The peripapillary retinal nerve fibre layer (pRNFL), macular ganglion cell complex (mGCC), radial peripapillary capillary (RPC) and macular vasculature were measured by optical coherence tomography and angiography. Correlation and regression analyses were used to assess the association of area under log CSF (AULCSF), CSF acuity and contrast sensitivities at multiple spatial frequencies with structural parameters.

RESULTS

AULCSF and CSF acuity were positively associated with pRNFL thickness, RPC density, mGCC thickness and superficial macular vessel density (p<0.05). Those parameters were also significantly associated with contrast sensitivity at 1, 1.5, 3, 6, 12, 18 cycles per degree spatial frequencies (p<0.05) and, the lower the spatial frequency, the higher the correlation coefficient. RPC density (p=0.035, p=0.023) and mGCC thickness (p=0.002, p=0.011) had significant predictive value for contrast sensitivity at 1 and 1.5 cycles per degree, with adjusted R 2 of 0.346 and 0.343, respectively.

CONCLUSIONS

Full spatial frequency contrast sensitivity impairment, most notably at low spatial frequencies, is a characteristic change in POAG. Contrast sensitivity is a potential functional endpoint for the measurement of glaucoma severity.

Extraction of three-dimensional shapes in glaucoma patients in response to monocular depth cues

PURPOSE

To assess the impact of glaucoma on perceiving three-dimensional (3D) shapes based on monocular depth cues.

STUDY DESIGN

Clinical observational study.

METHODS

Twenty glaucoma patients, subjected to binocular visual-field sensitivity (binocular-VFS) tests using a Humphrey Visual Field Analyzer, and 20 age-matched healthy volunteers, underwent two tasks: identifying the nearest vertex of a 3D shape using monocular shading (3D-SfS), texture (3D-SfT), or motion (3D-SfM) cues, and distinguishing elementary one-dimensional (1D) features of these cues. The association of the visual-field index (VFI) of binocular-VFS with 3D shape perception in glaucoma patients was also examined.

RESULTS

Glaucoma patients demonstrated reduced accuracy in distinguishing 1D luminance brightness and a larger "error-in-depth" between the perceived and actual depths for 3D-SfM and 3D-SfS compared to healthy volunteers. Six glaucoma patients with a 100% VFI for binocular-VFS exhibited a similar error-in-depth to the other fourteen glaucoma patients; they had a larger error-in-depth for 3D-SfM compared to healthy volunteers. No correlation between the error-in-depth values and the VFI values of binocular-VFS was observed.

CONCLUSIONS

The 3D shape perception in glaucoma patients varies based on the depth cue's characteristics. Impaired 1D discrimination and larger thresholds for 3D-SfM in glaucoma patients with a 100% VFI for binocular-VFS indicate more pronounced perceptual deficits of lower-level elementary features for 3D-SfS and higher-level visual processing of 3D shapes for 3D-SfM. The effects of the location and degree of binocular visual-field defects on 3D shape perception remain to be elucidated. Our research provides insights into the 3D shape extraction mechanism in glaucoma.

Correlation of contrast sensitivity with ganglion cell/inner plexiform layer thickness and damage location in glaucoma with varying severity

OBJECTIVES

To investigate the correlation of contrast sensitivity with macular region ganglion cell/inner plexiform layer (GC/IPL) thickness and damage location in open-angle glaucoma (OAG) of varying severity.

METHODS

Cross-sectional study with 106 patients (203 eyes) who had OAG. Contrast sensitivity of each eye evaluated by quick contrast sensitivity function test based on intelligent algorithm. The GC/IPL thickness measured with optical coherence tomography; six sectors were delineated for localization of damage area. All eyes were grouped by the healthy macular sector and divided into pre-perimetric, early, moderate, and advanced stages, according to severity of visual field impairment.

RESULTS

Mean GC/IPL thickness in the entire macular region and each sector were correlated with parameters that reflected contrast sensitivity (p < 0.01). The structure-function correlations were stronger nasally compared with temporally, and superiorly compared with inferiorly. Eyes with normal structure in inferior temporal sector had less visual field (p' = 0.024) and macular damage (p' = 0.034) compared with eyes that had healthy superior nasal sector; there was no difference in contrast sensitivity (p = 0.898). The structure-function correlations were significant in early, moderate, and advanced glaucoma (p < 0.05) but not in pre-perimetric glaucoma (p = 0.116).

CONCLUSIONS

GC/IPL thinning in all sectors of the macular region in OAG was correlated with contrast sensitivity impairment, whereas the inferior temporal sector was least affected. Contrast sensitivity was supported as a severity evaluation indicator of early, moderate, and advanced glaucoma, but not of pre-perimetric glaucoma.

Bilaterally subluxed diffractive intraocular lenses: big expectations and even bigger comorbidities

A 78-year-old woman with an ocular history of cataract surgery with a diffractive intraocular lens (IOL) in each eye has developed fluctuating vision, greater in the right eye than the left eye, after 4 years. She has a history of inactive central serous retinopathy and a vision potential of 20/25 + 2 in the right eye and 20/25 in the left eye. She has well-controlled diabetes, hypertension, and hypercholesterolemia. She has enjoyed her spectacle independence for some time and wishes to have her vision restored. On examination, her uncorrected distance visual acuity (UDVA) was 20/50 in the right eye and 20/25 in the left eye and her uncorrected near visual acuity (UNVA) was J3 in the right eye and J1 in the left eye. Intraocular pressures (IOPs) measured 22 mm Hg in the right eye and 18 mm Hg in the left eye. Pupils had limited reactivity with irregularity in the right eye but no obvious relative afferent pupillary defect. Motility and confrontation visual fields were unremarkable in both eyes. Retinal acuity meter was 20/20 in both eyes, and manifest refraction was plano -1.25 × 105 20/40, J3 in the right eye and +0.50 × 20/25, J1 in the left eye. Pertinent findings on slitlamp examination included temporal iris atrophy and transillumination defects greater in the right eye than the left eye, peripupillary pseudoexfoliative changes in both eyes, significant inferior subluxation of a diffractive 3-piece posterior chamber IOL in the capsular bag with lens-pitting peripherally and few central, moderate pseudophacodonesis, and an open posterior capsule in the right eye. In the left eye, she had mild inferior subluxation of a single-piece acrylic diffractive IOL in the capsular bag with moderate pseudophacodonesis and an open posterior capsule (Figure 1JOURNAL/jcrs/04.03/02158034-202403000-00019/figure1/v/2024-02-20T193212Z/r/image-tiff). All other anterior segment findings were unremarkable. On dilated posterior examination, she had a cup-to-disc ratio of 0.50 in the right eye and 0.65 in the left eye without edema hemorrhage or pallor. There were attenuated vessels in both eyes, posterior vitreous detachment in both eyes, and a few small drusen peripherally in both eyes. There was retinal pigment epithelium irregularity and dropout parafoveal in the right eye and subfoveal in the left eye (Figure 2). There was no evidence of macular edema, subretinal fluid, choroidal thickening, or neovascular membranes. The periphery was unremarkable in both eyes.JOURNAL/jcrs/04.03/02158034-202403000-00019/figure2/v/2024-02-20T193212Z/r/image-tiff What testing would you obtain preoperatively to help guide your decision-making? How would you counsel the patient regarding comorbid conditions and expectations?

Influence of Diabetes Mellitus on Glaucoma-Relevant Examination Results in Primary Open-Angle Glaucoma

Primary open-angle glaucoma (POAG) is no longer considered an isolated eye pressure-dependent optic neuropathy, but a neurodegenerative disease in which oxidative stress and neuroinflammation are prominent. These processes may be exacerbated by additional systemic diseases. The most common are arterial hypertension, dyslipidemia, and diabetes mellitus. Using diabetes mellitus as an example, it will be shown how far-reaching the influence of such a systemic disease can be on both the functional and the structural diagnostic methods for POAG. This knowledge is essential, since these interferences can lead to misinterpretations of POAG, which can also affect therapeutic decisions.

The impact of visual function on staircase use performance in glaucoma

OBJECTIVES

This cross-sectional study aimed to investigate the relationship between visual function and staircase use in glaucoma.

METHODS

Overall, 181 patients with glaucoma with a best-corrected visual acuity ≥20/400 were classified into mild to moderate (mean deviation [MD] ≥ -12 dB) and advanced (MD < -12 dB) groups, according to 24-2 VF of the worse eye. Staircase use evaluation included stair descent and ascent time (SDT/SAT) and self-reported stair difficulty. Correlations between staircase use and visual function were analysed, including binocular visual acuity, integrated visual field (IVF), and binocular contrast sensitivity (CS). Linear and logistic regression adjusted by age, sex, and comorbidities inspected the effect of visual parameters on SDT/ SAT and stair difficulty.

RESULTS

Visual function best correlated with SDT among staircase use. In mild to moderate glaucoma, area under the log CS function (AULCSF) (β = -1.648, P = 0.031) was the only visual factor significant for SDT (adjusted R2 = 0.106), whereas AULCSF (β = -1.641, P = 0.048) and MD of IVFINF0-24 (β = -0.089, P = 0.013) were associated with SDT in advanced glaucoma (adjusted R2 = 0.589). The AULCSF was the only significant visual parameter related to SAT (β = -1.125, P = 0.019) and stair difficulty (adjusted odds ratio = 0.003; 95% confidence interval, 0-0.302; P = 0.013).

CONCLUSIONS

SDT provides a higher correlation with visual function than self-reported stair difficulty. Patients with impaired CS or inferior IVF defects should be advised on stair safety and referred to low-vision services.

The associations of self-perception, movement competence, and clinical features of young school-aged children with glaucoma

The purpose of the study was to determine the associations of self-perception, motor skills, and clinical features of young school-age children with glaucoma (CG). This is a cross-sectional observational study. Children from preschool to second grade, including CG (N = 19), children with amblyopia (CA, N = 28), and controls (N = 32), completed the Manual Dexterity and Aiming and Catching Scales of the Movement Assessment Battery for Children-2nd edition (MABC-2), including Manual Dexterity, Aiming and Catching, and Balance. CG, CA, and their parent completed the Pictorial Scale of Perceived Competence and Social Acceptance for Young Children, respectively, assessing the child's cognitive competence, peer acceptance, physical competence, and maternal acceptance. The Kruskal-Wallis H test and Bonferroni post hoc test compared motor skills among groups. Spearman's correlation analysis evaluated the correlations between motor skills, self-perception, and clinical features. The CG reported lower peer acceptance than CA (P = 0.040), and the parents of CG reported lower cognitive competence than CG reported (P = 0.046). Compared with controls, CG had worse performance of Aiming and Catching, and Balance (P = 0.018 and P = 0.001), and CA had worse performance of Balance (P = 0.009). The motor skills were comparable between CG and CA. For CG, older age correlated with worse competence of Aiming and Catching (r =  - 0.620, P = 0.005), better best-corrected visual acuity of better-seeing eye correlated with higher competence of Manual Dexterity and Balance (r =  - 0.494, P = 0.032, and r =  - 0.516, P = 0.024), and longer duration of glaucoma correlated with worse competence of Manual Dexterity (r =  - 0.487, P = 0.034).

CONCLUSION

 Glaucoma and amblyopia have significant negative impacts on children's daily motor skills. The acuity of a better-seeing eye is an important factor influencing motor movement.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, ChiCTR2100050415.

WHAT IS KNOWN

• The state of mental health in early childhood influences the development of their future personality and physical development. The prognosis and management of glaucoma may seriously impair the mental health development of the affected children. However, the exploration of psychological aspects and motor movement of childhood glaucoma was limited.

WHAT IS NEW

• Children with glaucoma have impaired motor skills and self-perception development, especially in terms of peer socialization.

Clinical outcomes after implantation of a new monofocal intraocular lens with enhanced intermediate function in patients with preperimetric glaucoma

Purpose

We evaluated the clinical outcomes after implantation of a new monofocal intraocular lens (IOL) with enhanced intermediate function in patients with preperimetric glaucoma and compared those with patients without retinal nerve fiber layer (RNFL) defects.

Methods

All patients were implanted bilaterally a new monofocal IOL with enhanced intermediate function. Patients with bilateral RNFL defects and no glaucomatous visual field defects were classified as the preperimetric glaucoma group. A total of 60 eyes of 30 patients with preperimetric glaucoma were compared with 60 eyes of 30 patients without RNFL defects. Uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), defocus curve, contrast sensitivity, and questionnaire were evaluated 1 month and 3 months after surgery.

Results

No difference in binocular UDVA, UIVA, and UNVA was evident between the two groups at 1 and 3 months postoperatively. Additionally, there were no significant differences between the two groups regarding the proportion of severe or very severe photic phenomena, such as glare and halos, or the overall satisfaction.

Conclusion

Bilateral implantation of a new monofocal IOL with enhanced intermediate function in patients with preperimetric glaucoma demonstrated commensurate clinical outcomes and could be considered a feasible alternative.

Can children measure their own vision? A comparison of three new contrast sensitivity tests

PURPOSE

To investigate the feasibility of children measuring their own contrast sensitivity using a range of tablet- and paper-based tests.

METHODS

Forty children aged 5-15 years with amblyopia (N = 10), bilateral vision impairment (N = 10) or good vision (N = 20) measured their own vision on a screen-based optotype test (Manifold), a gamified vision test (PopCSF) and a paper-based test (Spotchecks) in a laboratory with minimal supervision. Completion rate, test-retest repeatability, test duration and participants' preferences were recorded for each test.

RESULTS

Most participants (36/40) were able to perform all three tests. All tests were correlated with clinically measured visual acuity and contrast sensitivity (p < 0.001). The 95% coefficient of repeatability was 0.30 dB for Manifold, 0.29 dB for PopCSF and 0.13 dB for Spotchecks. All tests differentiated between children with reduced contrast sensitivity and control participants. PopCSF and Spotchecks were also able to differentiate between children with amblyopia and those with good vision. Median test time was 152, 130 and 202 s for Manifold, PopCSF and Spotchecks, respectively. Twenty-two participants preferred the PopCSF test, 10 preferred Spotchecks and 6 preferred Manifold. Thirty-nine out of the 40 children (98%) said they would measure their own vision at home using at least one of these tests every month.

CONCLUSIONS

Children and young people can test their own contrast sensitivity with repeatable results. Of these three tests, the most repeatable was Spotchecks, the quickest was PopCSF and participants' favourite was PopCSF. Nearly all of the participants said they would be willing to use at least one of the three tests at home.

Comparison of the Visual Outcomes of Enhanced and Standard Monofocal Intraocular Lens Implantations in Eyes with Early Glaucoma

This study aimed to compare the efficacies and safety of enhanced and standard monofocal intraocular lenses (IOLs) in eyes with early glaucoma. Patients with concurrent cataracts and open-angle glaucoma (OAG) were enrolled. They underwent cataract surgery with IOL implantation. The comprehensive preoperative ophthalmic examination included the manifest refraction; monocular uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected intermediate visual acuity (UIVA), and uncorrected near visual acuity (UNVA); visual field (VF); and contrast sensitivity (CS); defocus curves and questionnaires were assessed three months postoperatively. Totals of 34 and 38 patients had enhanced and standard monofocal IOLs, respectively. The enhanced monofocal IOL provided better UIVA than the standard monofocal IOL (p = 0.003) but similar UDVA, CDVA, and UNVA. The enhanced monofocal IOL had more consistent defocus curves than the standard monofocal IOL, especially at -1 (p = 0.042) and -1.5 (p = 0.026) diopters. The enhanced monofocal IOL provided better satisfaction (p = 0.019) and lower spectacle dependence (p = 0.004) than the standard monofocal IOL for intermediate vision, with similar VF and CS outcomes. In conclusion, enhanced monofocal IOLs are recommended for patients with OAG because they provide better intermediate vision, higher satisfaction, and lower dependence on spectacles than standard monofocal IOLs, without worsening other visual outcomes.

Five-Year Visual Field Outcomes of the HORIZON Trial

PURPOSE

To compare visual field (VF) progression between glaucoma patients receiving cataract surgery alone (CS) or with a Hydrus microstent (CS-HMS).

DESIGN

Post hoc analysis of VF data from the HORIZON multicenter randomized controlled trial.

METHODS

A total of 556 patients with glaucoma and cataract were randomized 2:1 to either CS-HMS (369) or CS (187) and followed up for 5 years. VF was performed at 6 months and then every year after surgery. We analyzed data for all participants with at least 3 reliable VFs (false positives < 15%). Average between-group difference in rate of progression (RoP) was tested using a Bayesian mixed model and a 2-sided Bayesian P value <.05 (main outcome). A multivariable model measured the effect of intraocular pressure (IOP). A survival analysis compared the probability of global VF sensitivity dropping by predefined cutoffs (2.5, 3.5, 4.5, and 5.5 dB) from baseline.

RESULTS

Data from 352 eyes in the CS-HMS arm and 165 in the CS arm were analyzed (2966 VFs). The mean RoP was -0.26 dB/y (95% credible interval -0.36, -0.16) for CS-HMS and -0.49 dB/y (95% credible interval -0.63, -0.34) for CS. This difference was significant (P = .0138). The difference in IOP only explained 17% of the effect (P < .0001). Five-year survival analysis showed an increased probability of VF worsening by 5.5 dB (P = .0170), indicating a greater proportion of fast progressors in the CS arm.

CONCLUSIONS

CS-HMS has a significant effect on VF preservation in glaucoma patients compared with CS alone, reducing the proportion of fast progressors.

Binocular Summation of Visual Acuity at High and Low Contrast in Early Glaucoma

PRCIS

This study examined the integrity of binocular summation function in patients with mild glaucoma. We found that binocular summation of visual acuity is preserved in these patients, despite their reduced monocular inputs.

PURPOSE

Binocular summation represents superiority of binocular to monocular performance. In this study we examined the integrity of binocular summation function in patients with early glaucoma who had structural glaucomatous changes but otherwise had no significant interocular acuity asymmetry or other functional deficit detected with standard clinical measures.

MATERIALS AND METHODS

Participants included 48 patients with early glaucoma according to Hodapp, Anderson, and Parrish 2 (HAP2) criteria (age 65±12 y) and 42 healthy controls (age 60±12 y), matched for stereoacuity. Visual acuity was assessed binocularly and monocularly at high (95%) and low (25%) contrast using the Early Treatment Diabetic Retinopathy Study (ETDRS) charts at 6 m. Binocular acuity summation was evaluated utilizing a binocular ratio (BR).

RESULTS

Overall, binocular and monocular visual acuity of the control group was better than that of the glaucoma group for both contrast levels, P =0.001. For the glaucoma group, there was a significant difference between BRs at high and low contrast, 0.01±0.05 and 0.04±0.06 ( P =0.003), respectively. For the control group, the difference between BR at high and low contrast was not statistically significant, 0.00±0.07 and 0.02±0.06 ( P =0.25), respectively.

CONCLUSION

For patients with early glaucoma, binocular summation function for visual acuity was preserved at both contrast levels. This suggests an adaptation of the visual system in early stages of glaucoma that allows for normal binocular summation in the presence of reduced monocular visual input.

Clinical Outcomes of a Non-Diffractive Extended Depth-of-Focus IOL in Eyes with Mild Glaucoma

Purpose

To evaluate the clinical outcomes of a non-diffractive, wavefront-shaping extended depth-of-focus (EDOF) intraocular lens (IOL) in eyes with mild open-angle glaucoma (OAG).

Setting

Private practice; Sioux Falls, South Dakota.

Design

Prospective, open-label, interventional study.

Methods

In total, 52 eyes of 26 patients with mild OAG were enrolled and completed the study. All patients were bilaterally implanted with a non-diffractive, wavefront-shaping EDOF IOL. Seventy-seven percent of the patients were implanted with a trabecular microbypass stent at the time of surgery. Primary outcome measures included binocular corrected and uncorrected distance visual acuity (CDVA and UDVA), uncorrected intermediate and near visual acuity (UIVA and UNVA) and contrast sensitivity as measured by a Pelli-Robson chart. A subjective questionnaire was also administered to patients.

Results

At 4 months postoperative, the mean binocular UDVA and CDVA was 0.03 ± 0.12 and -0.06 ± 0.07, respectively. The mean UIVA and UNVA were 0.18 ± 0.12 and 0.31 ± 0.18, respectively. Eighty-five percent of the subjects achieved ≥20/25 UDVA and 77% of the subjects achieved ≥20/32 UIVA at 4 months postoperative. The mean binocular mesopic contrast sensitivity was 1.76 ± 0.16 at a spatial frequency of 1 cycle-per-degree (cpd). Eighty-five percent of the subjects reported they would choose the same lens and 1 subject reported they would choose a different IOL if it meant reduced spectacle independence.

Conclusion

The non-diffractive, wavefront-shaping EDOF IOL can be safely implanted in eyes with mild, pre-perimetric open-angle glaucoma with favorable uncorrected distance and intermediate visual acuity. The contrast sensitivity measurements were favorable and the subjective questionnaire revealed satisfactory spectacle independence and patient satisfaction.

Foveal crowding appears to be robust to normal aging and glaucoma unlike parafoveal and peripheral crowding

Visual crowding is the inability to recognize a target object in clutter. Previous studies have shown an increase in crowding in both parafoveal and peripheral vision in normal aging and glaucoma. Here, we ask whether there is any increase in foveal crowding in both normal aging and glaucomatous vision. Twenty-four patients with glaucoma and 24 age-matched normally sighted controls (mean age = 65 ± 7 vs. 60 ± 8 years old) participated in this study. For each subject, we measured the extent of foveal crowding using Pelli's foveal crowding paradigm (2016). We found that the average crowding zone was 0.061 degrees for glaucoma and 0.056 degrees for age-matched normal vision, respectively. These values fall into the range of foveal crowding zones (0.0125 degrees to 0.1 degrees) observed in young normal vision. We, however, did not find any evidence supporting increased foveal crowding in glaucoma (p = 0.375), at least in the early to moderate stages of glaucoma. In the light of previous studies on foveal crowding in normal young vision, we did not find any evidence supporting age-related changes in foveal crowding. Even if there is any, the effect appears to be rather inconsequential. Taken together, our findings suggest unlike parafoveal or peripheral crowding (2 degrees, 4 degrees, 8 degrees, and 10 degrees eccentricities), foveal crowding (<0.25 degrees eccentricity) appears to be less vulnerable to normal aging or moderate glaucomatous damage.

Contrast Sensitivity Changes after Phototherapeutic Keratectomy in Heterozygote Granular Corneal Dystrophy Type 2

Purpose: Contrast sensitivity, the ability to distinguish the relative difference in luminance of an object from its surrounding or adjacent objects, is a useful measure of visual function. In granular corneal dystrophy type 2 (GCD2), opacity of the corneal stroma causes deterioration in visual function. We compared the contrast sensitivity of GCD2 patients before and after phototherapeutic keratectomy (PTK) to evaluate the perioperative visual function in these patients.Methods: This study included 22 eyes of heterozygote GCD2 patients. The visual acuity and contrast sensitivity were measured before and after PTK. The contrast sensitivity was measured in mesopic and photopic background luminances, with glare (G) levels of 0-2 (G0, G1, and G2, respectively) and spatial frequencies at 1.5, 3, 6, 12, and 18 cycles per degree (cpd).Results: The contrast sensitivity increased after PTK at 1.5 and 3 cpd in mesopic and photopic conditions with G0-2 glare (p < 0.05). At 6 cpd, the contrast sensitivity increased in the mesopic condition with G1 glare, and in the photopic condition with G0-2 glare (p < 0.05). However, there was no change in contrast sensitivity at any glare level at 12 and 18 cpd after PTK.Conclusions: In GCD2 patients, the contrast sensitivity increased significantly after PTK. The vision of GCD2 patients, which is decreased due to corneal opacity, is improved after PTK.

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.

Polymyositis and dermatomyositis: ocular manifestations and potential sight-threatening complications

Dermatomyositis (DM) and polymyositis (PM) are idiopathic inflammatory myopathies characterized by progressive, symmetric, mainly proximal muscle weakness. DM is also characterized by cutaneous involvement. However, other clinical features, systemic involvement, histopathological findings, response to treatment, and prognosis, differ significantly. Although uncommon, ocular manifestations in DM and PM may potentially affect any structure within the eye. Notwithstanding being generally mild, ocular involvement in DM and PM may result in significant morbidity. Left untreated, significant retinal inflammation associated with hemorrhage and detachment may occur, leading to significant vision loss. This review aims to present an up-to-date overview for rheumatologists about the ocular involvement and potential complications of DM and PM and when to refer to the ophthalmologist to avoid sight-threatening complications.

Distracted Driving and Driving Patterns in Older Drivers With Glaucoma

Limited research exists examining self-perceived vision and driving ability among individuals with glaucoma, and this study assessed the relationship between glaucoma, visual field, and visual acuity with driving capability.

137 individuals with glaucoma and 75 healthy controls were asked to evaluate self-rated vision, self-perceived driving ability, and self-perceived distracted driving. Visual acuity and visual field measurements were also obtained. Multivariable linear regressions were run to test each visual measure with driving outcomes.

The average age was 72.2 years, 57.3% were male, and 72.5% were White. There were significant associations for a one-point increase in visual field and quality of corrected vision (RR = 1.06; 95% CI = 1.03–1.10), day vision (RR = 1.05; 95% CI = 1.03–1.08), night vision (RR = 1.08; 95% CI = 1.05–1.13), visual acuity score and higher quality of corrected of vision (RR = .41; 95% CI = .22-.77), day vision (RR = .39; 95% CI=.22–.71), and night vision (RR = .41; 95% CI = .18–.94); visual acuity score and ability to drive safely compared to other drivers your age (RR = .53; 95% CI = .29–.96).

Individuals with poorer visual acuity and visual fields rate their vision and ability to drive lower than those with better vision, and this information will allow clinicians to understand where to target interventions to enhance safe driving practices.

Sensitivity to Central Crowding for Faces in Patients With Glaucoma

PRECIS

Some patients with glaucoma report difficulties to recognize faces when they are far away. We show that this deficit could result from a higher sensitivity to crowding in central vision.

PURPOSE

The aim of the study is to investigate whether face recognition difficulties reported by some patients with glaucoma result from a greater sensitivity to inner crowding in central vision.

METHODS

Seventeen patients with glaucoma and 17 age-matched normally sighted controls participated in the study. An isolated mouth (uncrowded condition) or a mouth within a face (crowded condition) was randomly displayed centrally for 200 ms. For each condition, participants were asked to decide whether the mouth was closed or open. The stimuli were presented at 3 angular sizes (0.6×0.4, 1×0.72, and 1.5×1.08 degrees). Accuracy was measured.

RESULTS

Crowding affected performance differentially for patients and controls. Consistent with previous studies controls exhibited a "face superiority effect," with a better accuracy when the mouth was located within the face than when it was isolated. Sensitivity to crowding, reflected in a better accuracy with the isolated mouth, was observed in 10 of 17 patients only for small images. Crowding disappeared for larger faces, as the facial features were spaced out. Five patients were not sensitive to crowding. Importantly, no difference was found between the 2 subgroups of patients (sensitive vs. nonsensitive) in terms of mean deviation, contrast sensitivity, acuity, thickness of the retinal nerve fiber layer, or macular ganglion cell-inner plexiform layer.

CONCLUSIONS

An excessive sensitivity to central crowding might explain the difficulties in face perception and reading reported by some patients with glaucoma. The sensory or cognitive processes underlying this excessive sensitivity must be elucidated to improve central perception in glaucoma.

High-Pass Visual Acuity Loss and Macular Structure-Function Relationship in Patients With Primary Open-Angle Glaucoma

Purpose

The Logarithm of the Minimum Angle of Resolution (logMAR) chart is the most common clinical test for assessing central visual function in glaucoma. However, based on the use of these charts, visual acuity (VA) often remains normal even when severe macular damage exists. Here, we aim to investigate the potential advantages of high-pass VA in detecting glaucoma compared with conventional VA.

Methods

Monocular best-corrected VA measurements were compared for a novel high-pass electronic VA chart (e-chart) and a conventional e-chart in 113 primary open-angle glaucoma (POAG) patients with normal logMAR VA and 65 age-similar healthy controls. One hundred thirty-nine POAG patients underwent spectral-domain optical coherence tomography (SD-OCT) for measurement of macular ganglion cell layer plus inner plexiform layer (GCL+IPL) thickness. Structure-function relationships between OCT measurements and the two VAs were compared. The enrolled eyes were divided into two groups for further analyses according to macular visual field (MVF) defects, specifically two or more adjacent abnormal points within the 12 central sites of 30-2 VF.

Results

The mean deviation (MD) of 30-2 VF test was -12.77 ± 7.47 dB for glaucoma group and -1.70 ± 1.12 dB for control group. The mean difference of the two VAs was slightly larger in glaucoma group (0.29 logMAR) than in control group (0.22 logMAR). The area under the receiver operating characteristic curve of the high-pass e-chart was larger than that of conventional e-chart (0.917 vs. 0.757, P < 0.001). Significant correlations between high-pass VA and GCL+IPL thickness were found only in the MVF-damaged group. Compared with conventional VA, high-pass VA demonstrates stronger correlations with nasal-side macular GCL+IPL thickness (Fisher's Z-test, two-tailed, P2mmin diameter = 0.033 and P3mmin diameter = 0.005).

Conclusions

Compared with conventional VA, high-pass VA displays slightly higher sensitivity to visual loss in glaucoma and has a stronger correlation with the nasal-side macular GCL+IPL thickness.

Translational Relevance

The high-pass acuity test has the potential to be used as an ancillary tool to monitor glaucoma over time.

Visual Function and Patient Satisfaction with Multifocal Intraocular Lenses in Patients with Glaucoma and Dry Age-Related Macular Degeneration

Purpose

To report visual function and self-reported satisfaction of patients with glaucoma and dry age-related macular degeneration (dAMD) implanted with multifocal intraocular lenses (MIOL).

Methods

Patients with glaucoma or dAMD as well as healthy individuals implanted with MIOL were invited to participate. Explorations performed were uncorrected and corrected distance visual acuity (UDVA and CDVA), low-contrast visual acuity (LCVA), binocular contrast sensitivity, and defocus curves. Patients completed the Catquest-9 questionnaire and reported on the presence of dysphotopsias and the need for spectacles.

Results

38 subjects were included: 11 in the healthy/control group and 9 each in the preperimetric glaucoma, perimetric glaucoma, and dAMD groups. Controls had statistically better monocular UDVA, CDVA, and LCVA than patients with glaucoma and dAMD, as well as better binocular acuity in the defocus curves between −2.00 D and +0.50 D. Differences between controls and patients with preperimetric glaucoma were not statistically significant. Between −3.0 D and +0.5 D, all groups except dAMD achieved acuities better than 0.2 logMAR. Patients with dAMD had worse contrast sensitivity than all others for 3 cycles per degree (cpd), and patients with glaucoma had worse values than all others for 12 cpd; other differences did not reach statistical significance. Healthy subjects and patients with preperimetric glaucoma perceived halos more often than patients with glaucoma or dAMD, while suffering less from glare. Patients with glaucoma and dAMD found more difficulties when driving at night and required spectacles for near more often than the other subjects. Patients with dAMD were less satisfied with their vision.

Conclusions

MIOLs may be implanted in patients with preperimetric glaucoma with little fear of patient dissatisfaction. In glaucoma and dAMD, MIOLs might be considered with caution, after explaining the increased risk of glare and the higher need for spectacle correction for reading.

Association of ocular blood flow and contrast sensitivity in normal tension glaucoma

Purpose

To investigate the relationship of ocular blood flow (via arteriovenous passage time, AVP) and contrast sensitivity (CS) in healthy as well as normal tension glaucoma (NTG) subjects.

Design

Mono-center comparative prospective trial

Methods

Twenty-five NTG patients without medication and 25 healthy test participants were recruited. AVP as a measure of retinal blood flow was recorded via fluorescein angiography after CS measurement using digital image analysis. Association of AVP and CS at 4 spatial frequencies (3, 6, 12, and 18 cycles per degree, cpd) was explored with correlation analysis.

Results

Significant differences regarding AVP, visual field defect, intraocular pressure, and CS measurement were recorded in-between the control group and NTG patients. In NTG patients, AVP was significantly correlated to CS at all investigated cpd (3 cpd: r =  − 0.432, p< 0.03; 6 cpd: r =  − 0.629, p< 0.0005; 12 cpd: r =  − 0.535, p< 0.005; and 18 cpd: r =  − 0.58, p< 0.001), whereas no significant correlations were found in the control group. Visual acuity was significantly correlated to CS at 6, 12, and 18 cpd in NTG patients (r =  − 0.68, p< 0.002; r =  − 0.54, p< .02, and r =  − 0.88, p< 0.0001 respectively), however not in healthy control patients. Age, visual field defect MD, and PSD were not significantly correlated to CS in in the NTG group. MD and PSD were significantly correlated to CS at 3 cpd in healthy eyes (r = 0.55, p< 0.02; r =  − 0.47, p< 0.03).

Conclusion

Retinal blood flow alterations show a relationship with contrast sensitivity loss in NTG patients. This might reflect a disease-related link between retinal blood flow and visual function. This association was not recorded in healthy volunteers.

Low-Contrast High-Pass Visual Acuity Might Help to Detect Glaucoma Damage: A Structure-Function Analysis

Purpose: The conventional visual acuity (VA) test is not sensitive enough to detect glaucoma macular damage. We aimed to investigate whether VA measurements using low-contrast high-pass optotypes are more sensitive to macular dysfunction in glaucoma and to find the potential structural basis of this difference.

Methods: A total of 147 subjects were recruited, including 118 patients with glaucoma (mean age: 46.08 ± 14.64 years) and 29 healthy controls (mean age: 39.83 ± 9.81 years). For each participant, monocular best-corrected VA was measured using a conventional chart and six high-pass charts at 100, 50, 10, 5, 2.5, and 1.25% contrast levels, respectively. The macular retinal thickness and circumpapillary retinal nerve fiber layer (cpRNFL) thickness of all the glaucoma patients were obtained by spectral-domain optical coherence tomography (SD-OCT).

Results: Compared with healthy subjects, glaucoma patients with normal vision demonstrated worse VAs in high-pass acuity measurements (0.22–0.93 vs. 0.28–1.08, p < 0.05). Receiver operating characteristic curve (ROC) showed that 1.25% low-contrast high-pass VA was optimal for discriminating between the controls and glaucoma patients (AUC: 0.918, p < 0.001; sensitivity: 77.33%; specificity: 96.55%). Compared with conventional VA, 1.25% high-pass VA correlated better with nasal-side macular retinal ganglion cell (RGC)-related parameters (r = −0.419 to −0.446 vs. r = −0.538 to −0.582; Fisher's Z transformation, p_z < 0.05). There was no difference in the strength of correlations between the VAs measured using different charts and cpRNFL thickness (Fisher's Z transformation; p_z > 0.05).

Conclusions: VA measurement taken with low-contrast (1.25%) high-pass acuity chart is more sensitive in detecting central visual loss in glaucoma than that taken with the conventional chart. Macular RGC damage appears to be associated with low-contrast (1.25%) high-pass visual loss in glaucomatous eyes.

Pharmacological Effects of Saffron and its Constituents in Ocular Disorders from in vitro Studies to Clinical Trials: A Systematic Review

Introduction:

Some medicinal plants have shown promising therapeutic potential for the management of the diseases. We aimed to systematically review the literature wherein the therapeutic effects of saffron have been studied on eye disorders.

Methods

A systematic literature search was performed in PubMed, Scopus, Web of Science, Google scholar and other databases using eye disorders and saffron as key terms. No strict inclusion criteria were defined, and almost all clinical studies, as well as in vivo and in vitro studies were included. The reported data in each study were extracted and then qualitatively described.

Results

Finally, 78 articles were found but only 29 relevant articles were included. Nine articles were clinical trials and 20 articles were studies conducted on cellular and molecular aspects of saffron on eye disorders. According to the included studies, crocin prevented the pro-inflammatory response in retinal cells and decreased glucose levels in diabetic mice. Also, crocetin prevented retinal degeneration and saffron protected photoreceptors from light-induced damage in retinal cells. Saffron also improved visual function in age-related macular edema and decreased intraocular pressure in patients with glaucoma. In addition, it was shown that crocin can improve best corrected visual acuity and decrease central macular thickness in patients with diabetic maculopathy.

Conclusion

The results of this review indicated that saffron and its main ingredients such as crocin could be a potential candidate for the treatment of ocular disease especially eye inflammation; however, further clinical studies are needed to confirm such efficiency.

Characteristics of Glaucoma Patients Attending a Vision Rehabilitation Service

PURPOSE

In this study, we describe common demographic and clinical characteristics of the glaucoma patient population attending vision rehabilitation.

DESIGN

Cross-sectional study.

PARTICIPANTS

Patients attending a hospital-based vision rehabilitation center with a primary ocular diagnosis of glaucoma.

METHODS

Participants' charts were retrospectively reviewed. Data extracted from medical records included demographics, referring physician, ocular history, glaucoma diagnosis, past ocular surgery, intraocular pressure, optic nerve findings, results of a functional intake assessing activities of daily living, depression, visual hallucinations, best-corrected visual acuity (BCVA), mean deviation (MD) scores on visual field testing, and log contrast sensitivity (CS).

MAIN OUTCOME MEASURES

Participant demographic information, ocular history, self-reported difficulty with activities of daily living, depression, visual hallucinations, BCVA, visual field, and CS.

RESULTS

The mean age of patients in this study was 77 years and ranged from 8 to 103 years. Ninety percent of patients were referred to vision rehabilitation by an ophthalmologist. Median BCVA was 20/50. Fifty-five percent of patients were functionally monocular, and for all patients, there was a median 9-line difference in BCVA between eyes. Median MD score was -13.95 decibels (dB). Median CS was 1.05. Patients reported having the greatest difficulty with reading (88%), writing (72%), and mobility (67%). Seventy-eight percent of patients stopped driving, and 12% reported difficulty driving. Among those experiencing depression, there was a 4:1 ratio of depressed patients having difficulty with mobility. One-third of patients experienced visual hallucinations.

CONCLUSIONS

Most glaucoma patients attending vision rehabilitation are not legally blind, but many are functionally monocular. This may cause greater difficulty performing functions that require the use of binocularity. Increasing the referral of younger glaucoma patients to vision rehabilitation may help patients learn to cope with the loss of visual function that occurs over time.

Glaucoma and Computer Use: Do Contrast and Color Enhancements Improve Visual Comfort in Patients?

PURPOSE

To estimate the impact of glaucoma on computer use and to assess specific adaptations of the graphical interface to this form of visual impairment.

DESIGN

Prospective, experimental cohort study.

PARTICIPANTS

Forty-nine participants were recruited: 16 patients with primary open-angle glaucoma (mean ± SD, 62.7 ± 5.6 years of age), 17 age-matched participants (mean ± SD, 59.1 ± 8.3 years of age), and 16 young control participants (mean ± SD, 23.3 ± 2.1 years of age).

METHODS

An ophthalmologic examination before the study evaluated the level of visual loss (mean deviation), visual acuity (logarithm of the minimum angle of resolution units), and contrast sensitivity (CS) of the primary open-angle glaucoma patients. Each participant underwent the following measurements: an information technology (IT) experience questionnaire, a preference task monitored by eye tracking, and a feedback session. The experimental task was based on ecological computer scenes with 3 enhancement levels (low, medium, and high), determined by gradual modulation of contrast, luminance, and color. Participants were asked to select the most readable and comfortable stimulus among 4 images displayed on the screen: the original computer scene and 3 enhanced versions.

MAIN OUTCOME MEASURES

Clinical, oculomotor, and subjective data were computed together in a multivariate model by using a principal component analysis (PCA).

RESULTS

The PCA revealed 3 principal components accounting for 72% of the total variance of the data and showed a greater need for enhanced computer scenes in glaucoma patients, an equal preference for low and medium enhancement within the 3 groups, and significantly longer oculomotor behavior in the patient groups. Subjective reports of difficulty using IT because of vision were correlated with visual impairment and high enhancement preference. Contrast sensitivity was critical to explaining the main variations of the data. A reduced CS had a significant effect on the preference for enhanced computer scenes (r = -0.43; P < 0.002) and a less effective exploration velocity (r = 0.43; P < 0.002).

CONCLUSIONS

Glaucoma alters the global exploration of computer scenes. High enhancement of the graphical interface could improve visual comfort during computer use. Subjective patients' reports underline the importance of including IT questions in visual-related quality-of-life questionnaires.