Low vision services: a practical guide for the clinician

Visual Impairment and Low Vision Aids-A Comparison between Children and Adults

(1) Background: This study aims to highlight differences in the etiology and fitting of low vision aids in visually impaired children and adolescents in comparison to adults. (2) Methods: A retrospective data collection from visually impaired patients presenting to obtain assistive devices from 1 January 2016 to 30 April 2020 was conducted. A total of 502 patients were included. Inclusion criteria were a minimum age of 4 years and the chart notation of a best-corrected distance visual acuity in the patient record prior to the fitting of magnifying visual aids. (3) Results: Of the 502 patients, 147 (29.3%) were children under the age of 18 years. The most common cause of visual impairment in children was albinism, and in adults, it was age-related macular degeneration (AMD). Children showed better distance visual acuity, with a median of 0.88 logMAR (Logarithm of the Minimum Angle of Resolution) compared to 1.0 in adults (p = 0.001). Near visual acuity was also significantly better, with a median of 0.54 logMAR in children compared to 0.9 in adults (p < 0.001). Near and distance visual acuity were significantly improved by fitting magnifying visual aids (p < 0.001). After fitting, near visual acuity averaged 0.3 logMAR, and distance visual acuity, 0.7. The most commonly prescribed aids were optical vision aids, which 68.5% of the patients received; 43.8% received electronic aids. In children, optical aids were more frequently prescribed, and in adults, electronic and acoustic aids (p < 0.001). (4) Conclusion: Visually impaired patients can regain the ability to read and improve distance vision by using individually adapted and tested magnifying vision aids, often with optical aids alone. Differences between children and adults could be discovered in the etiology and severity of visual impairment, as well as in the provision type of low vision aids.

Compliance With the Use of Low-Vision Aids in a Greek Population: An Explorative Study

The aim of this study is to investigate the compliance with low-vision aids (LVAs) among patients with low vision (LV) in a Greek population. An explorative study was conducted in a sample of patients with LV attending our outpatient unit at the School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece. Patients' demographics and daily visual demands were recorded, and they were administered with the National Eye Institute Visual Function Questionnaire-25 (VFQ-25) at baseline. Participants were trained in the use of a wide range of LVAs before their prescription. Evaluation of the use of the LVAs was conducted at one year after the baseline using a structured phone survey. A total of 100 LV patients were included, with 68% of them being older than 65 years and 50 being males. The main cause of LV (57.0%) was age-related macular degeneration, and the mean VFQ-25 score at baseline was 49.2 (SD= 17.8). Overall, 75 patients had been prescribed LVAs, with 76.0% of these patients preferring an optical aid. The vast majority (98.7%) of these patients stated using the LVA one year after the baseline, and 62.1% of them reported using the aid often to very often. Significantly, 76% of these patients reported that their quality of life was positively affected by the use of the aid, and 97.3% would recommend the use of LVA to another individual with the same problem. Providing appropriate training before the prescription is of high significance to improve the rate of compliance with the use of LVAs. These results can be used to develop appropriate strategies in this field.

Cost-benefit analysis of orientation and mobility programs for adults with vision disability: a contingent valuation study

PURPOSE

The purpose of this study is to conduct a cost-benefit analysis of orientation and mobility (O&M) programs from three perspectives: the general public, the experienced, and the potential users of O&M programs.

METHODS

Willingness-to-pay (WTP) for O&M programs was collected via a contingent valuation survey using a double-bound dichotomous choice approach. WTP was estimated using interval regression analyses, accounting for study arm, sex, occupation, income, and self-rated health. The cost data were estimated from a service provider's perspective. The net present value (NPV), variation if delivered by tele-O&M, was investigated.

RESULTS

The adjusted mean NPV of O&M programs was $3857 (95% CI: $3760-$3954) per client, with highest NPV from the general public ($4289, 95% CI: $4185-$4392), followed by the experienced users ($3158, 95% CI: $2897-$3419) and the potential users ($2867, 95% CI: $2680-$3054). The NPV reached break-even for tele-O&M.

CONCLUSIONS

There was strong community support for investment into O&M programs considering benefits for clients over and above the cost of providing the services.Implications for rehabilitationThis study demonstrates the feasibility of using cost-benefit analysis with a contingent valuation approach to economically assess a rehabilitation intervention, where its multi-dimensional benefits cannot be fully captured by a conventional appraisal technique such as cost-effectiveness analysis.The high willingness-to-pay (WTP) values amongst the general public suggests that Australians perceive government's investment in orientation and mobility (O&M) rehabilitation as value for money and that individuals would be prepared to contribute to its costs.The lower WTP for O&M partially delivered via tele-practice (tele-O&M) indicates a lower acceptance of this innovation in comparison with the traditional face-to-face O&M.The estimated net present values of O&M programs, positive for traditional O&M and break-even for tele-O&M, can be of assistance to service planning and investment decisions within the Australian context.

Current Management Options for Patients with Retinitis Pigmentosa

With an estimated prevalence of 1 in 4000 worldwide [1], retinitis pigmentosa (RP) comprises a spectrum of progressive inherited retinal disorders that can lead to blindness as early as age 30 [2]. Despite its relatively high prevalence and devastating consequences, RP does not have a definitive cure. Therapeutic attempts have been made with nutritional supplementation, but these strategies only have proven benefit in a limited number of patients with rare forms of RP. Thus, current standards of care involve regular follow-up, management of associated ocular pathology such as macular edema and cataracts, and genetic counseling and low vision rehabilitation. In recent years, gene therapy, visual prostheses, and stem cell therapy have emerged as FDA-approved treatments for RP, but these options are not yet widely used. Herein, this chapter will discuss the therapeutic strategies listed above that comprise the current standards of care and briefly discuss some emerging options.

Low Vision Referral Patterns in Intermediate Age-Related Macular Degeneration

PURPOSE

Sparse data exist regarding low vision (LV) services referral patterns. We retrospectively examined our institution's intermediate age-related macular degeneration (iAMD) patients to determine factors influencing referral.

METHODS

We compared visual acuity (VA) and Visual Function Questionnaire (VFQ-25) composite and subscale scores for referred and non-referred iAMD patients. VA was collected at time of referral or most recent visit, and VFQ-25 was taken upon enrollment into the registry.

RESULTS

Thirty-six (15.5%) of the 232 iAMD patients were referred to LV. Referred patients were more likely to have older age, worse VA in both eyes, and lower VFQ-25 scores. Univariate analysis of VFQ-25 subscales demonstrated worse scores in general vision, near, distance, mental health, role limitations, dependency, and driving. Multivariable analysis revealed lower scores in general health, general vision, and driving. Forty-eight percent of non-referred patients had VA or VFQ-25 composite scores at least as poor as the median for referred patients. Two-thirds of patients who were not referred had no discernable obstacle to referral.

CONCLUSIONS

Our institution refers patients with worse objective and functioning vision, but more patients may benefit from referral. Future studies should identify metrics to prompt referral and evaluate this approach.

Preference of low vision devices in patients with central field loss and peripheral field loss

PURPOSE

The objective of this study was to estimate the profile of patients visiting low vision care clinic at a tertiary eye care center in India and to analyze the preference of low vision devices (LVD).

METHODS

A retrospective review was done for 450 patients with low vision who were referred to the LVC clinic from January 2019 to December 2019. The participants were categorized into two groups as central field loss (CFL) and peripheral field loss (PFL). Demographic profile details and low vision device preference were documented.

RESULTS

Out of 450 patients, 242 (53.8%) were diagnosed to have CFL and 208 (46.2%) had PFL. The median age of the overall patients was 34.5 years. Overall, 323 (71.8%) were men and 127 (28.2%) were women. Cone dystrophy (21.1%) was the major cause of low vision among atrophic changes (54.1%) in CFL, and retinitis pigmentosa (81.2%) was the majority in retina related changes (81.7%) in PFL. Overall, 71.3% of the low vision patients preferred LVD. CFL group (76%) preferred LVD more than PFL group (65.9%). Almost 34% of the patients in both CFL and PFL group have preferred half eyes and Ashperics, followed by 32.5% in CFL and 28.1% in PFL preferred dome magnifiers. Statistically significant improvement in distance and near vision with the help of LVD was noted.

CONCLUSION

The use of LVD can help patients with low vision in restoring useful vision, where medical and surgical treatment have no or a limited role.

Demand preferences for health management services in a population of older adults with visual impairment in China: a conjoint analysis

Background

Visual impairment (VI) seriously affects the quality of life of the older adults. It is important to formulate appropriate health management strategies for the older adults with VI to help delay the disease development and progression, and improve life quality. The aim of this study was to understand the demand preference for health management services of the older adults with VI, and to provide a reference for the development of future health management strategies in this population.

Methods

The conjoint analysis method was used to analyze demand preferences for health management services of the older adults with VI. 11 keywords were extracted after literature analyzed, 6 keywords were selected as the attributes of health management strategy after expert discussion and the level of each attribute was determined. Then 18 representative virtual health management strategies were formed by combination of different attribute levels through orthogonal design, and older adults with VI were asked to score. A total of 334 older adults with VI who attended the ophthalmology department of the First Affiliated Hospital of China Medical University and the Fourth People's Hospital of Shenyang from February 27, 2021 to June 30, 2021were enrolled in this study by stratified sampling. Of the 334 included people, 80 had grade 1 VI, 80 had grade 2 VI, 84 had grade 3 VI, and 90 had grade 4 VI.

Results

The relative importance of health management services ranked by older adults with VI was continuing care (24.033%), visual aid application (19.61%), health education (16.241%), preventive healthcare (15.667%), safety management (12.757%), and rehabilitation training (11.392%). The utility values of each level of continuing care, safety management and preventive healthcare were positive, whereas the utility values of each level of visual aid application, health education and rehabilitation training were negative. The relative importance and utility values of health management services were different for the older adults with different grades of VI.

Conclusions

From the whole group, the older adults with VI have a higher preference for continuing care and a lower preference for rehabilitation training. The preference of the older adults with different grades of VI is different, so medical workers can formulate corresponding health management strategies according to their different demand preferences, and carry out hierarchical health management. Services that they preferred should be satisfied as much as possible in the health management strategy, while the reasons for the services with lower preference can be explored and make targeted improvement to meet the demand preferences of them.

Barriers to Low-Vision Rehabilitation Services for Visually Impaired Patients in a Multidisciplinary Ophthalmology Outpatient Practice

Low-vision rehabilitation (LVR) has significant benefit in improving the quality of life of visually impaired patients. However, these services are highly underutilized in ophthalmology practices. A quality improvement study was performed to investigate barriers to LVR services for patients at the University of Texas Medical Branch (UTMB) between 2010 and 2020. Low vision was defined as the best corrected visual acuity of 20/70 or worse in the better-seeing eye or a visual field less than 20 degrees. Potential subjects were screened (n = 577) from the electronic medical record using International Classification of Disease (ICD) codes for legal blindness, impaired vision, and low vision. Chart review identified 190 subjects who met criteria for low-vision analysis. Patients who received LVR referrals to attend at least one LVR service visit from the eligible subjects were contacted for participation in phone interviews regarding their LVR experience. Practicing eye care providers (ECPs) at UTMB completed a questionnaire to capture their referral patterns. Of the eligible subjects, 64% were referred to LVR services by ECPs. Reported patient barriers included mental health issues (76%), denial of need for low-vision aid (71%), poor physical health (67%), lack of transportation (57.1%), and lack of referrals (36%). EPCs reported patient's overall health (67%), older age (44%), lack of social support (44%), poor cognitive function (44%), and low likelihood of follow-up (44%) as barriers to referring patients to LVR. This study identified several modifiable barriers that can be addressed to access LVR services for low-vision patients. Changing referral patterns, eliminating variations in referral criteria, and increasing patient awareness and knowledge of LVR resources may tremendously improve the quality of life of low-vision patients.

Low Vision Management in A 5-Years-Old Due to Retinopathy of Prematurity for Life Quality Improvement

Introduction: Management of low vision in pediatric patients with greater result  can affect their quality of life than in adult low vision patients.. Retinopathy of Prematurity is the main cause of blindness in children. A case study highlights the tertiary prevention (low vision examination and management) in a 5 year old boy with ROP related blindness to optimize his remaining visual capacity by using optical and  non optical aids that support daily activity and educational learning.Case Report: A 5 year old boy with ROP related blindness visited to the low vision clinic after receiving the several treatments for ROP before. His visual acuities were light perception in the right eye and hand movement in the left eye using his current spectacle correction. He had anti VEGF bevacizumab intravitreal injection, vitrectomy and complicated cataract extraction history on the left eye. He wasdifficult to learn and read numbers and alphabets caused by visual impairment.Discussion : Upon evaluation by assessment low vision method, his distance visual acuity in the left eye was improved significantly up to 3/40 on LEA Acuity chart with +14.00D. His near vision became 10 M at 30 cm of reading distance (without near correction) and 4 M at 13 cm  improved with +3.00 D by spectacle. The non optical aid devices as reading task were also suggested to improove continuous  reading text without difficulty.Conclusion: ROP blindness can be preventable if appropriate, adequate and accessible screening programmes are available. Unfortunately, even with the current screening guidelines and recommended treatment of ROP, many babies suffer from blindness by this disease each year. Low vision assessment and management in pediatric patient with visual impairmentaccording to children’s need can optimize the recent visual capability of low vision patient and give self care daily activity and educational learning.

Standardizing the Assessment of Macular Pigment Using a Dual-Wavelength Autofluorescence Technique

PURPOSE

It is essential to have an appropriate measure to assess macular pigment (MP) that can provide an accurate, valid, and reliable representation of the MP within the macula. The aim of this study was to describe and introduce MP optical volume (MPOV) as an optimal value for reporting MP.

METHODS

Three hundred ninety-three subjects were analyzed using the Heidelberg Spectralis with the investigational MP optical density (MPOD) module to measure MPOV and MPOD at four foveal eccentricities (0.23°, 0.51°, 0.98°, 1.76° [7° as reference point]). Lutein (L) and zeaxanthin (Z) dietary intake and serum concentrations were evaluated.

RESULTS

MPOV mean was 5094 (95%CI, 4877-5310); range: 527 to 10,652. MPOV was inversely correlated with body mass index and positively correlated with education (r = -0.156, P = 0.002 and r = 0.124, P = 0.014, respectively). Serum concentrations of L and Z were positively correlated with MPOV (r = 0.422, P < 0.001 and r = 0.285, P < 0.001, respectively). MPOV was positively correlated to MPOD at all measured eccentricities, with the strongest agreement at 1.76° (r = 0.906, P < 0.001). Serum concentrations of L and Z, BMI, education, and age (P < 0.001) were found to be significant predictors of MPOV.

CONCLUSIONS

The Spectralis MPOV measurement provided a comprehensive and detailed evaluation of the MP profile. The Spectralis MPOV should be considered a preferred metric for the assessment of MP.

TRANSLATIONAL RELEVANCE

Applying a standardized method for the assessment and report of MP will allow to fully derive meaning from observational studies and to successfully implement this MP measurement technique in research and clinical settings.

A Common Approach to Low Vision: Examination and Rehabilitation of the Patient with Low Vision

Due to the increasing age of the global population, rates of visual disability are increasing. Visual rehabilitation is an effective method for increasing quality of life among individuals with low vision or blindness due to unpreventable or untreatable causes. The goal of low vision rehabilitation is to produce people who are independent, have an economically viable profession or skill, and are able to enjoy their lives. The stages of modern low vision rehabilitation include the intake interview, assessment of residual visual functions, assessment of residual functional vision, interventions and recommendations, and vision rehabilitation therapies.