Subjective vision assessment in companion dogs using dogVLQ demonstrates age-associated visual dysfunction

Introduction

Dim light vision as assessed by proxy and clinical tools is commonly impaired in older humans and impacts quality of life. Although proxy visual assessment tools have been developed for dogs, it is unclear if they are sensitive enough to detect subtle visual dysfunction in older dogs. We sought to determine if a newly designed proxy visual function questionnaire could detect age-associated differences in visual behaviors in varying lighting conditions in dogs.

Methods

A 27-item questionnaire (the dog variable lighting questionnaire, dogVLQ) was designed to assess visual behavior in dogs in different lighting settings. We conducted the dogVLQ, a previously validated visual function questionnaire the dog vision impairment score and performed light- and dark-adapted electroretinography (ERG) on a subset of dogs. Questionnaire scores were analyzed for dog age associations using correlation analysis.

Results

Questionnaire responses from 235 dog owners were obtained (122 female, 112 male dogs), 79 of which underwent ERG (43 female, 36 male dogs). Bright light visual behavior was significantly associated with light-adapted bright flash ERG amplitudes, visual behavior in near darkness was associated with dark-adapted ERG amplitudes. The dogVLQ identified worse vision in older dogs in bright light, dim light, and darkness; predicted onset was younger for vision in near darkness. Older dogs had more difficulty navigating transitions between lighting conditions.

Discussion

Subjective dog owner assessment of visual function associates with objective measurement of retinal function in dogs and supports reduced vision-mediated behaviors in older dogs.

The efficacy of neuro-optometric visual rehabilitation therapy in patients with visual snow syndrome

Objective

This study intends to evaluate the feasibility of Neuro-Optometric Rehabilitation Therapy (NORT) to treat Visual Snow Syndrome (VSS). This pilot study utilized the National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) to assess quality of life (QOL) before and after treatment.

Methods

Twenty-one participants were recruited as successive intake patients diagnosed with VSS at the clinics of Dr. Terry Tsang Optometry, Inc and Neuro-Vision Associates of North Texas. Participants completed the NEI Visual Function Questionnaire 25-2000 edition and performed NORT, conducted by a neuro-optometrist or a qualified vision therapist. The NEI-VFQ-25 was administered before, at 6 weeks, and at 12 weeks of NORT to evaluate the effects of treatment on patient QOL.

Results

The participants demonstrated an improvement in QOL composite and subscale scores after 6 and 12 weeks of NORT treatment. The NEI-VFQ-25 composite scores from the pre-test (M = 68, SD = 18) and at 6 weeks of treatment (M = 75, SD = 17) indicate an improvement in QOL [t (20) = 4.0, p = 0.0007]. The NEI-VFQ-25 composite scores from pretest to 12 weeks of treatment showed further improvements. This trend of improvement on NEI-VFQ-25 composite scores continued into the 12th week (M = 77, SD = 17) of treatment [t (20) = 4.5, p = 0.0002]. The subscales of general vision, distance activities, near activities, social functioning, mental health, role difficulties and dependency also showed improvement.

Conclusion

Our results suggest that patients with VSS experience improvement in QOL in as little as 6 weeks, with further improvement by 12 weeks of NORT. This suggests NORT is an effective treatment option for managing the condition and improving QOL in patients with VSS, although a reduction in specific symptoms has yet to be demonstrated. This study provides justification that NORT warrants further investigation on VSS symptom reduction.

Vision-Related Quality of Life and Seasonal Affective Disorder in Patients with Glaucoma and Macular Degeneration

Seasonal affective disorder (SAD) is characterized by depressive episodes related to changes in the seasons. Patients with severe vision loss are at an increased risk of SAD. This study seeks to determine the extent to which patients with moderate vision loss report symptoms of SAD. In this cross-sectional, comparative case series, the Seasonal Pattern Assessment Questionnaire (SPAQ) and the National Eye Institute Visual Function Questionnaire (VFQ-39) were used to screen 111 patients with age-related macular degeneration (AMD) and/or primary open-angle glaucoma (POAG). A multiple regression analysis was performed to create a predictive model for SAD based on the Global Seasonality Score (GSS) using the VFQ-39. Subjects who reported symptoms of SAD (GSS > 8) had lower vision-related quality of life (composite score: 57.2 versus 73.2, p < 0.001). Exploratory factor analysis revealed that the items on the VFQ-39 split into two distinct dimensions that together accounted for 63.2% of the total variance in the GSS. One group of questions addressed vision-related problems; the other group comprised questions related to the quality of life. Whereas this model successfully identified patients with vision loss at risk of SAD, a model restricted to the questions available on the shorter, widely used VFQ-25 instrument did not reliably identify patients at risk of SAD.

The impact of advanced age-related macular degeneration on the National Eye Institute's Visual Function Questionnaire-25

PURPOSE

To assess visual function among patients diagnosed with age-related macular degeneration (AMD) by stage of disease and laterality.

METHODS

This is a cross-sectional cohort study of 739 AMD patients and their responses to the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25) at time of study enrolment. Patients with AMD were categorized into Early/Intermediate AMD and three groups of advanced AMD: (i) neovascular AMD (NV), (ii) geographic atrophy (GA) and (iii) Both Advanced forms. These three advanced stages were further stratified into unilateral or bilateral advanced disease. Mean composite scores and subscale scores for 12 different areas were based on a 100-point scale with the lowest and highest possible scores set at 0 and 100, respectively. Scores for the advanced AMD groups were compared with Early/Intermediate AMD using general linear modelling.

RESULTS

A total of 739 AMD patients (294 Early/Intermediate, 115 GA, 168 NVAMD and 162 Both Advanced) were included in the analysis. Mean composite scores were highest among Early/Intermediate patients (89.9), followed by patients diagnosed with unilateral disease in the Both Advanced (88.0) and NV (86.1) groups. Mean composite scores were similar for bilateral NV (82.9) and unilateral GA (81.7), and mean scores were lowest for the bilateral GA (71.3) and bilateral Both Advanced (68.5) groups. In general, this pattern persisted across the twelve subscales as well. Subscale scores ranged from a low of 35.1 for driving among bilateral Both Advanced patients to a high of 99.2 for colour vision among patients with unilateral Both Advanced. Overall, patients with unilateral advanced disease consistently had higher mean scores than their bilateral counterparts. The largest difference was 19.5 composite score points between the unilateral and bilateral Both Advanced groups, there was a difference of 10.4 points between the GA groups, and a relatively small difference of 3.2 points between the NV groups.

CONCLUSIONS

We found large differences in visual function as reported from the VFQ-25 across the different types of advanced stage AMD groups and number of eyes affected with advanced AMD. These findings demonstrate the importance of accounting for the type and number of eyes affected by advanced stage AMD.

Prevalence and predictors of colour vision defects among Egyptian university students

Background

Nowadays, widespread usage of colours increases the need for accurate estimation of colour vision defects and their effect on performing daily activities and study/work tasks.

Aims

To determine the prevalence and predictors of colour vision defects among Assiut university students and to identify their relationship with self-reported visual function and perceived difficulties in performing daily activities.

Methods

A cross-sectional study was conducted among 1426 students at Assiut University, Egypt. Data were collected by self-administered questionnaire consisting of: personal characteristics, prior awareness of colour vision defects, difficulties in daily colour vision activities, and visual function. Colour vision was assessed using Ishihara's test of colour deficiency.

Results

The prevalence of colour vision defects among students was 6.9% (red-green colour vision was 4.3% and total colour blindness was 2.6%). Students with colour vision defects had significantly higher odds ratios for difficulties in daily activities and study/work tasks related to colour perception. Students with colour vision defects had significantly lower mean values of general health, role difficulties, and colour vision scores compared to students with normal colour insight. Male sex and family history of colour vision defects were risk factors.

Conclusions

A non-negligible percentage of Egyptian university students had colour vision defects, which had a negative impact on performing daily activities, executing study/work tasks, and choice of study/work specialties. Colour vision defects affected quality of life with regard to general health, role difficulties and colour vision. Male sex and family history of colour vision defects are nonmodifiable risk factors. This emphasizes the need for genetic counselling, especially in consanguineous marriage.

Effects of the Argus II Retinal Prosthesis System on the Quality of Life of Patients With Ultra-Low Vision Due to Retinitis Pigmentosa: Protocol for a Single-Arm, Mixed Methods Study

Background

Retinitis pigmentosa is an incurable, degenerative retinal condition causing progressive sight loss, significantly affecting patients’ quality of life. The Argus II Retinal Prosthesis is a surgically implanted medical device that delivers electrical stimulation to the retina. It is intended to produce a form of artificial vision for blind people with severe-to-profound retinitis pigmentosa by stimulating the remaining viable retinal cells to induce visual perception. This study has been initiated by National Health Service England’s Commissioning through Evaluation program and funded through the National Institute of Health Research of the United Kingdom.

Objective

The aim of this study was to assess the effect of the Argus II device on patient’s daily activities and quality of life.

Methods

This protocol is a prospective, single-arm, open-label, mixed methods study on 10 consecutive participants receiving the Argus II device. The patient representatives played an integral role in the design of this study. Eligibility criteria include ultra-low vision in both eyes as a result of end-stage retinitis pigmentosa and a willingness and capacity to complete the postimplantation rehabilitation program. Participants will be interviewed by independent researchers at baseline and 12 months later by using a semistructured, in-depth approach, alongside validated questionnaires (Impact of Vision Impairment-Very Low Vision, 5-level EuroQoL-5 dimensions scale, EuroQoL-visual analog scale, and Hospital Anxiety and Depression Scale) and a bespoke device-related questionnaire, which includes questions about users’ experiences with the procedure, the device, and rehabilitation. The effect of the device on patients’ functional vision and activities of daily living will be assessed by vision rehabilitation specialists using a set of tests measured on an ordinal scale (eg, ability to locate objects and avoid obstacles). Clinical outcomes include full-field stimulus light threshold, square localization, direction of motion, grating visual acuity, Landolt-C, procedural success, and adverse events. Qualitative and quantitative outcomes will be linked in a single database to enable individual participant measures to be considered in toto, comparing baseline to the final review.

Results

This study was approved by the local ethics committee on April 24, 2019 (London-Camberwell St. Giles Research Ethics Committee, reference 19/LO/0429). It has also been approved by the Health Research Authority and Health and Care Research Wales. At the time of protocol writing, Argus II was available for use in the United Kingdom; however, the manufacturer recently withdrew the Argus II device from sale in the United Kingdom. Therefore, the study is not going ahead at this time.

Conclusions

The mixed methods approach provides a rich and in-depth assessment of the effect of the device on participants’ quality of life. Despite the work not going ahead, the publication of this publicly funded protocol is important for researchers planning similar work.

International Registered Report Identifier (IRRID)

PRR1-10.2196/17436

Full-field Electroretinography in Age-related Macular Degeneration: can retinal electrophysiology predict the subjective visual outcome of cataract surgery?

PURPOSE

Predicting the visual gain from cataract surgery when the main cause of vision loss is age-related macular degeneration may be difficult and warrants the need for an objective predictor of subjective outcome. Full-field electroretinography is an objective measure of overall retinal function. We therefore wanted to study if full-field electroretinography can predict subjective visual outcome using visual function questionnaire.

METHODS

Thirty-one patients with age-related macular degeneration operated for bilateral cataract underwent full-field electroretinography preoperatively. Full-field electroretinography was performed according to International Society for the Clinical Electrophysiology of Vision standards using a Ganzfeld bowl (RETI-port/scan 21, Roland, Berlin) and Dawson-Trick-Litzkow fibre electrodes. Vision-related quality of life was measured using the National Eye Institute Visual Function Questionnaire-39 before first-eye surgery and 4.12 ± 2.11 months after second-eye surgery.

RESULTS

Mean change in composite visual function questionnaire score after cataract surgery was 9.2 ± 11.9. The patients were divided into three groups: visual function questionnaire composite score increase >10 (n = 17); no change (n = 8); and decrease (n = 6). In the dark-adapted full-field electroretinography responses, we found a significant difference between the three groups in the 0.01 b-wave amplitude (p = 0.05), the 10.0 b-wave amplitude (p = 0.04) and a near-significant difference in 3.0 a-wave amplitude (p = 0.09). Other dark-adapted responses (the 3.0 b-wave and 10.0 a-wave) did not show any significant differences between the three groups, and neither did the light-adapted responses.

CONCLUSION

Patients with low dark-adapted responses on full-field electroretinography preoperatively experience a decrease in subjective vision-related quality of life, suggesting that maintained rod function before cataract surgery may be important.

Patient-reported outcomes of ocriplasmin for the treatment of vitreomacular traction: a systematic review and synthesis of the literature

Purpose

Vitreomacular traction (VMT) is a disease in which the vitreous exerts abnormally strong traction on the macula, the area of the eye responsible for detailed central vision. If this traction significantly distorts the macula then VMT can lead to troublesome distorted vision (metamorphopsia), sometimes occurring despite relatively preserved visual acuity. Ocriplasmin, administered as a single intravitreal injection, aims to release VMT and improve vision. While the effect of ocriplasmin on traction release and visual acuity is well characterized, the effect of symptoms like metamorphopsia is not.

Methods

A systematic review and synthesis of the literature on patient reported outcomes (PRO) in relation to the use of ocriplasmin for the treatment of VMT was undertaken using MED-LINE and Embase databases, and the Cochrane central register of controlled trials (CENTRAL).

Results

The review identified PRO data from 870 patients across three randomized controlled trials. The most commonly reported PROs were the 25-item National Eye Institute Visual Function Questionnaire (VFQ-25), a broad measure of vision-related quality of life, and Visual Function Response (VFR), an outcome combining quality of life and visual acuity outcomes. Treatment with ocriplasmin produced significant patient benefit vs control (sham or placebo-injection). Ocriplasmin was associated with a higher proportion of patients experiencing a clinically meaningful improvement in visual functioning with a difference of 11.8% for VFQ-25 and 23.2% for VFR responder analyses, respectively.

Conclusion

Patients with VMT have material impairment in visual functioning and quality of life, relative to their reduction in visual acuity. Ocriplasmin results in a significant improvement in visual functioning. Future research could include the development of new PROs specific to VMT.

Development of an Arabic version of the National Eye Institute Visual Function Questionnaire as a tool to study eye diseases patients in Egypt

AIM

To develop and test an Arabic version of the National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25).

METHODS

NEI-VFQ-25 was translated into Arabic according to WHO translation guidelines. We enrolled adult consenting patients with bilateral chronic eye diseases who presented to 14 hospitals across Egypt from October to December 2012, and documented their clinical findings. Psychometric properties were then tested using STATA.

RESULTS

We recruited 379 patients, whose mean age was (54.5±15)y. Of 46.2% were males, 227 had cataract, 31 had glaucoma, 23 had retinal detachment, 37 had diabetic retinopathy, and 61 had miscellaneous visual defects. Non-response rate and the floor and ceiling numbers of the Arabic version (ARB-VFQ-25) were calculated. Internal consistency was high in all subscales (except general health), with Cronbach-α ranging from 0.702-0.911. Test-retest reliability was high (intraclass correlation coefficient 0.79).

CONCLUSION

ARB-VFQ-25 is a reliable and valid tool for assessing visual functions of Arabic speaking patients. However, some questions had high non-response rates and should be substituted by available alternatives. Our results support the importance of including self-reported visual functions as part of routine ophthalmologic examination.