The use of augmented reality and virtual reality for visual field expansion and visual acuity improvement in low vision rehabilitation: a systematic review.

INTRODUCTION: Developments in image processing techniques and display technology have led to the emergence of augmented reality (AR) and virtual reality (VR)-based low vision devices (LVDs). However, their promise and limitations in low vision rehabilitation are poorly understood. The objective of this systematic review is to appraise the application of AR/VR LVDs aimed at visual field expansion and visual acuity improvement in low vision rehabilitation. METHODS: A systematic search of the literature was performed using MEDLINE, Embase, PsychInfo, HealthStar, and National Library of Medicine (PubMed) from inception to March 6, 2022. Articles were eligible if they included an AR or VR LVD tested on a sample of individuals with low vision and provided visual outcomes such as visual acuity, visual fields, and object recognition. RESULTS: Of the 652 articles identified, 16 studies comprising 382 individuals with a mean age of 52.17 (SD = 18.30) years, and with heterogeneous low vision etiologies (i.e., glaucoma, age-related macular degeneration, retinitis pigmentosa) were included in this systematic review. Most articles used AR (53%), VR (40%), and one article used both AR and VR. The main visual outcomes evaluated were visual fields (67%), visual acuity (65%), and contrast sensitivity (27%). Various visual enhancement techniques were employed including variable magnification using digital zoom (67%), contrast enhancements (53%), and minification (27%). AR LVDs were reported to expand the visual field from threefold to ninefold. On average, individuals using AR/VR LVDs experienced an improved in visual acuity from 0.9 to 0.2 logMAR. Ten articles were classified as high or moderate risk of bias. CONCLUSION: AR/VR LVDs were found to afford visual field expansion and visual acuity improvement in low vision populations. Even though the results of this review are promising, the lack of controlled studies with well-defined populations, use of small, convenience samples, and incomplete reporting of inclusion and exclusion criteria among included studies makes it challenging to judge the true impact of these devices. Future studies should address these limitations and compare various AR/LVDs to determine what is the ideal LVD type and vision enhancement combination based on the user's level of visual ability and lifestyle.

Validation of the visual acuity iPad app Eye Chart Pro compared to the standard Early Treatment Diabetic Retinopathy Study chart in a low-vision population.

INTRODUCTION: A low-vision assessment (LVA) is central to developing a vision rehabilitation plan. However, access to LVAs is often limited by the quantity and geographic distribution of low-vision providers, as well as patient-centred transportation challenges. A tablet-based LVA tool kit, delivered virtually, has the potential to overcome many of these barriers. The purpose of this research was to validate a key component of the tablet-based tool kit - a commercially available iPad visual acuity (VA) test (Eye Chart Pro) iPad app - in a low-vision population. METHODS: Participants with low vision (n = 26) and those who were normally sighted (n = 25) underwent VA testing with both the iPad VA test application and the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. The VA data were compared using a t-test, linear regression and Bland-Altman analysis. RESULTS: There was no significant difference in the mean absolute difference in VA (log of minimum angle of resolution (logMAR)=0.11; p = 0.82). Eye Chart Pro and Standard ETDRS Chart measures were also not significantly different (p = 0.98). However, there were significant differences between test methods in the low-vision group and the normally sighted group (p > 0.0001 and p = 0.007, respectively). The Bland-Altman analysis showed a mean bias (difference) of -0.0005 logMAR between methods, and 95% limits of agreement of 0.298 and -0.299 logMAR. DISCUSSION: The ETDRS chart function on the Eye Chart Pro application can reliably measure VA across a range, from normally sighted patients to those with low vision.

Validation of a portable, remotely delivered refraction approach compared to standard in-clinic refraction in a low-vision population.

INTRODUCTION: A low-vision assessment (LVA) is critical in developing a vision rehabilitation plan. A remotely delivered LVA that replicates a standard in-clinic assessment may bridge the gap for patients not accessing care due to the limited quantity and distribution of low-vision providers. Within an LVA, an accurate and consistent assessment of refraction error is an essential component. No system has currently been validated for the purposes of a remote LVA. The purpose of this study was to validate a commercially available portable refraction approach in a low-vision population. METHODS: Low-vision patients (n = 26) or normally sighted patients (n = 25) underwent a refraction assessment using the Adaptica® 2WIN autorefractor, adaptor scope (Kaleidos) and VisionFit phoropter portable refraction devices, as well as a standard autorefractor (Huvitz) and phoropter (Haag-Streit). Refraction data between systems and populations were compared using intraclass correlations. Bland-Altman plots were used to assess the differences between devices. RESULTS: Spherical equivalent values were found to be reproducible between standard and experimental autorefraction devices (intraclass correlation coefficient (ICC) > 0.8) in both low-vision and normally sighted groups. Similarly, manifest refraction was highly consistent (ICC > 0.8) between devices in all groups. The Bland-Altman plots showed clinically acceptable mean differences of 0.701 between autorefraction methods and -0.116 between manifest refraction methods. DISCUSSION: The 2WIN/VisionFit system can reliably generate refraction values across a spectrum of errors in normally sighted and visually impaired people, and would be feasible to deliver remotely.

Evaluating the efficacy of an educational ergonomics module for improving slit lamp positioning in ophthalmology residents.

OBJECTIVE: To characterize changes in body positioning while performing a standardized slit lamp examination after exposure to an educational module on ergonomics. DESIGN: Prospective interventional pilot study. PARTICIPANTS: Ten ophthalmology residents. METHODS: An educational module discussing ergonomic issues in ophthalmology was created. In a standardized examination lane, participants were recorded performing 3 trials of an indirect slit lamp examination of a volunteer patient, adjusting equipment as they saw fit. Participants were then sent the module and within 2 weeks repeated the trial process. Data were processed using biomechanical software to obtain the Rapid Upper Limb Assessment (RULA) injury risk score, elbow and shoulder joint reaction moments, neck and trunk flexion angles, and spinal curvature magnitudes. RESULTS: The RULA injury risk scores decreased after completion of the module (95% CI 2.10-2.77), indicating a lesser risk for injury to the resident. Shoulder flexion and elbow abduction moments also decreased (95% CI -3.2 to -1.5 and -0.44 to -0.04, respectively), suggesting a more neutral body posture. The trunk flexion angle increased after completion of the module (95% CI -5.1 to -1.6), signifying a more upright trunk posture; this was confirmed by the lumbar spine curvature, which flattened postmodule (95% CI 6.6-940). CONCLUSIONS: These results suggest a promising ability for an educational module to mitigate some injury risk in this population during indirect slit lamp examination. It also delineated some awkward postures that persisted despite the module. These results will be reintegrated into the module to optimize its educational utility.

Punctal Plug Retention Rates for the Treatment of Moderate to Severe Dry Eye: A Randomized, Double-Masked, Controlled Clinical Trial.

PURPOSE: To compare retention rates of Super Flex (Eagle Vision, Memphis, Tennessee, USA; Softplug-Oasis Medical Inc, Glendora, California, USA) vs Parasol (Odyssey Medical, Memphis, Tennessee, USA; Beaver Visitec International, Waltham, Massachusetts, USA) punctal plugs. DESIGN: Randomized, double-masked, interventional controlled clinical trial. METHODS: Institutional study at Hotel Dieu Hospital (Queen's University) of 50 eyes, from patients with moderate to severe dry eye. Each eye from eligible patients was separately randomized to receive Super Flex or Parasol punctal plugs. The main outcome measure was plug retention at 6 months. Secondary outcome measures included objective tests of Schirmer I (mm), tear meniscus height (mm), tear break-up time (s), inferior fluorescein corneal staining (National Eye Institute [NEI] scale), and average lissamine green conjunctival staining (NEI scale). RESULTS: Punctal plug retention was significantly different at 6 months (P = .011). Sixty-eight percent of Parasol plugs were retained compared to 32% of Super Flex plugs. Parasol plugs required less frequent artificial tear use at 6 months (P = .024). There was a statistically significant improvement in all secondary outcome measures (Schirmer, tear meniscus height, tear break-up time, fluorescein corneal staining) at 6 months within plug groups except conjunctival staining. There were no additional significant differences between groups and no plug complications reported. CONCLUSIONS: Punctal plugs improve symptoms of moderate to severe dry eye; however, retention rates differ significantly. These data will allow us to guide patient decision making for the safe and effective treatment of punctal plugs for moderate to severe dry eye.

Cyanoacrylate tissue adhesive on a polyglactin scaffold in strabismus surgery: a laboratory study.

BACKGROUND: The use of cyanoacrylate tissue adhesives in strabismus surgery has been variously successful, depending primarily on achieving adequate bond strength and minimizing extraocular muscle slippage. We investigate a novel approach to this problem, involving cyanoacrylate tissue adhesive on a polyglactin 910 scaffold as a means to secure extraocular muscle to the sclera for strabismus surgery. METHODS: In this experimental laboratory study, butyl-cyanoacrylate was used to fix a polyglactin 910 scaffold to the sclera of cadaver eyes. After allowing for polymerization, a force was applied to the mesh until the polyglactin-sclera bond failed. The maximum load (g) required for bond failure was recorded. The effects of surface area of the polyglactin 910 mesh as well as time required for cyanoacrylate tissue adhesive polymerization on bond strength were investigated. RESULTS: All combination of variables tested, except for experiments involving polyglactin 910 mesh that is 30 mm(2) with a polymerization time of 15 seconds or 30 seconds and polyglactin 910 mesh that is 40 mm(2) with a polymerization time of 15 seconds, achieved a bond strength that was significantly greater than those forces seen in a physiologic setting (P > 0.05). Increasing area or time resulted in increasing bond strength. Area and time were found to be independent variables. CONCLUSIONS: The cyanoacrylate tissue adhesive-derived polyglactin-sclera bond achieved a maximum load greater than those seen in a physiologic setting. Our novel approach demonstrates a clinically feasible alternative to traditional means for bonding muscle to sclera in strabismus surgery.

Predicting retinal tears in posterior vitreous detachment.

OBJECTIVE: The purpose of this study is to determine whether patients with acute posterior vitreous detachment (PVD) who develop delayed retinal tears within the first 6 weeks after initial presentation have predictive characteristics. DESIGN: Prospective cohort study. PARTICIPANTS: All patients presenting to the Hotel Dieu Hospital Emergency Eye Clinic between September 2008 and July 2009 diagnosed with acute PVD were offered enrollment. METHODS: At the initial visit, patients were given the previously validated Queen's University Posterior Vitreous Detachment Patient Diary to record their daily symptoms for 6 weeks. Two or 6 weeks later, patients were reexamined in detail, and their diaries were collected and analyzed. Exact logistic regression was used to establish characteristics predictive of delayed retinal tears. RESULTS: In our study population of 99 patients, 2 developed delayed retinal tears. One had retinal hemorrhages and the other had a cloud-like floater at initial presentation. Vitreal or retinal hemorrhage, large number of floaters at initial presentation, and high floater frequency at initial presentation indicated a high risk of delayed retinal tear formation, yielding a median unbiased estimated odds ratio of 36.18 with p value 0.009. No other presenting risk factors or symptomatology followed daily over the first 6 weeks after acute PVD were predictive of delayed retinal tear formation. CONCLUSIONS: PVD patients with retinal or vitreal hemorrhage, a significant number of floaters or a cloud like appearance to the floaters, or high floater frequency are at higher risk of developing delayed retinal tears.

Visual function analysis in acute posterior vitreous detachment.

OBJECTIVE: To determine whether the visual function of patients with posterior vitreous detachment (PVD)changes between the initial visit and a 6-week follow-up visit, and to compare their visual function with that of patients with macular degeneration, cataract, glaucoma, low vision, cytomegalovirus (CMV) retinitis, or diabetic retinopathy and a reference population. DESIGN: Prospective cohort study. PARTICIPANTS: All patients presenting to the Hotel Dieu Hospital Emergency Eye Clinic between September 2008 and June 2009 who were diagnosed with acute PVD were offered enrollment in the study. METHODS: Patients were administered the National Eye Institute Visual Function Questionnaire NEI VFQ-25 at two points in time. The composite scores from the initial and the 6-week visits were compared. The scores were also compared with established normative data and 6 ophthalmologic diagnoses. RESULTS: The NEI VFQ-25 composite score for patients with acute PVD (n = 84) at baseline was 93.26 ± 5.59 (mean ± SD). After 6 weeks and a second ocular examination, there was no statistical difference in the composite score of 93.47 ± 6.20 (mean ± SD). (1-sided paired t-test, t = 0.57; P = 0.28). CONCLUSIONS: The visual function of patients with acute PVD remains stable over the first 6 weeks after diagnosis. It is significantly higher than that of patients with 6 other ophthalmologic conditions but comparable to that of a normal population.

Validation of patient symptom diary in acute posterior vitreous detachment.

PURPOSE: The purpose of the study is to determine the validity of an original patient symptom diary in recording symptoms of posterior vitreous detachment (PVD). METHODS: In this prospective cohort study, all patients presenting to the Hotel Dieu hospital emergency eye clinic between September 2008 and July 2009 diagnosed with acute PVD were offered enrollment in the study. Patients were given the Queen's University posterior vitreous detachment patient diary at the initial visit after detailed eye examination, assessment of risk factors for retinal tears and detachments and a thorough explanation of their presenting complaints to record their symptoms related to PVD. At a random point during their six-week follow up, the patients were verbally asked the same questions being recorded in the diary over the phone. At the six-week follow up visit, the diaries were collected and the verbal results were compared with the written results. RESULTS: There was substantial to near perfect agreement between the verbal questions and written answers. Cohen's kappa scores for flash frequency, flash intensity, floater frequency, and floater type were 0.6229, 0.6389, 0.6495, and 0.8603, respectively. CONCLUSIONS: The Queen's University posterior vitreous detachment patient diary is a useful tool for investigating the quantity, quality and change in symptoms of patients presenting with PVD in the first 6 weeks of initial presentation.

Triaging herpes zoster ophthalmicus patients in the emergency department: do all patients require referral?

OBJECTIVES: The objective was to assess the predictive value of clinical signs and symptoms of herpes zoster ophthalmicus (HZO) for development of moderate to severe eye disease. METHODS: This was a prospective cohort multicenter study of 54 patients referred to the ophthalmology service after presenting to the emergency department (ED) or primary care clinic with a zosteriform rash of less than 10 days' duration. Upon referral to ophthalmology, easily assessable clinical signs and symptoms were documented. A complete ocular exam was then performed. Patients were followed for 2 months. RESULTS: Twenty-three patients (43%) developed moderate to severe disease as defined by corneal or intraocular involvement. Eye redness and rash in the supratrochlear nerve distribution had a statistically significant association with clinically relevant eye disease. All 23 patients who developed moderate to severe eye disease presented with a red eye. Hutchinson's sign (nasociliary nerve involvement) was not predictive of clinically relevant eye disease. CONCLUSIONS: Eye redness was 100% sensitive for predicting moderate to severe eye disease in this sample of patients and should necessitate immediate referral for ophthalmologic assessment. Patients lacking eye redness, even with a positive Hutchinson's sign, may not require immediate specialist consultation. All patients not being referred require careful instructions to seek further care should they develop any concerning eye symptoms such as redness, pain, photophobia, or visual disturbance.