Clinical research on the ophthalmic factors affecting 3D asthenopia

Effects of prolonged use of virtual reality smartphone-based head-mounted display on visual parameters: a randomised controlled trial

We investigated the effects of using a virtual reality smartphone-based head-mounted display (VR SHMD) device for 2 h on visual parameters. Fifty-eight healthy volunteers were recruited. The participants played games using VR SHMD or smartphones for 2 h on different days. Visual parameters including refraction, accommodation, convergence, stereopsis, and ocular alignment and measured choroidal thickness before and after the use of VR SHMD or smartphones were investigated. Subjective symptoms were assessed using questionnaires. We analyzed the differences in visual parameters before and after the use of VR SHMD or smartphones and correlations between baseline visual parameters and those after the use of the devices. Significant changes were observed in near-point convergence and accommodation, exophoric deviation, stereopsis, and accommodative lag after the use of VR SHMD but not after that of smartphones. The subjective discomfort associated with dry eye and neurologic symptoms were more severe in the VR group than in the smartphone group. There were no significant changes in refraction and choroidal thickness after the use of either of the two devices. The poorer the participants' accommodation and convergence ability the greater the resistance to changes in these visual parameters, and participants with a large exophoria were more prone to worsening of exophoria than those with a small exophoria.

Use of the heads-up NGENUITY 3D Visualization System for vitreoretinal surgery: a retrospective evaluation of outcomes in a French tertiary center

Heads-up three-dimensional (3D) surgical visualization systems allow ophthalmic surgeons to replace surgical microscope eyepieces with high-resolution stereoscopic cameras transmitting an image to a screen. We investigated the effectiveness and safety of the heads-up NGENUITY 3D Visualization System in a retrospective evaluation of 241 consecutive vitreoretinal surgeries performed by the same surgeon using conventional microscopy (CM group) over a 1-year period versus the NGENUITY System (3D group) over a consecutive 1-year period. We included for study vitreoretinal surgeries for treatment of retinal detachment (RD) (98 surgeries), macular hole (MH) (48 surgeries), or epiretinal membrane (ERM) (95 surgeries). A total of 138 and 103 eyes were divided into 3D and CM groups, respectively. We found no differences in 3-month postoperative rates of recurrence of RD (10% versus 18%, p = 0.42), MH closure (82% versus 88%, p = 0.69), or decrease in central macular thickness of ERMs (134 ± 188 µm versus 115 ± 105 µm, p = 0.57) between the 3D and CM groups, respectively. Surgery durations and visual prognosis were also similar between both groups. We consolidate that the NGENUITY System is comparable in terms of visual and anatomical outcomes, giving it perspectives for integration into future robotized intervention.

The impact of strabismus on psychosocial heath and quality of life: a systematic review

Strabismus can hinder an individual's ability to perform daily functions and negatively affect their well-being. I examine the impact strabismus has on psychosocial health and quality of life in children and adults and evaluate the challenges confronted by parents of children with strabismus. Numerous misconceptions exist regarding the impact strabismus has on overall health. Negative attitudes persist toward those affected, resulting in difficulties with self-image. Individuals with strabismus are at increased risk for both visual system and psychiatric disorders. Misinformation regarding available treatment options for children and adults with strabismus continues to exist, resulting in decreased access to care. Improved education of health care providers can increase appropriate referrals and initiation of treatment. Treatment of strabismus is not merely cosmetic and has the potential to improve psychosocial health and quality of life for children and adults with and without diplopia.

Can the Three-Dimensional Heads-Up Display Improve Ergonomics, Surgical Performance, and Ophthalmology Training Compared to Conventional Microscopy?

Purpose

To explore ophthalmic surgeons’ opinions regarding three-dimensional heads-up display (3D HUD) use and investigate musculoskeletal (MSK) complaints among ophthalmologists.

Methods

Physicians were invited to complete an online questionnaire. Musculoskeletal complaints and data of the HUD system use were correlated with demographic information. We explored surgeons’ feedback on image quality, depth perception, and the educational value of 3D microscopy.

Results

In this study, the prevalence of self-reported MSK pain was 82.6% (n=132). The pain started after joining ophthalmology practice and significantly improves on weekends and vacations. We found that the pain intensity in non-HUD users is higher than in HUD users, but this correlation was not statistically significant. Sixty-one (84.7%) of HUD system users were satisfied with depth perception, and 27 (37.5%) reported improvement in peripheral acuity. Thirty-seven (51.4%) of the participants believed they perform surgeries better through HUD; this was why most participants (83.3%) recommended its use in surgical training.

Conclusion

Heads-up display use provides more comfortable sitting positions for surgeons, superior depth perception, and serves as a better educational tool. We believe that adopting this technology may help improve career longevity and productivity.

Clinical experience of using the NGENUITY three-dimensional surgery system in ophthalmic surgical procedures

PURPOSE

To assess the clinical experience of using a three-dimensional (3D) system for ophthalmic surgical procedures.

METHODS

We retrospectively analysed video recordings of patients who underwent 3D ophthalmic surgery, using the NGENUITY^® 3D visualization system, or traditional microsurgery at our hospital, from August 2017 to February 2018. Patients underwent phacoemulsification or phacoemulsification combined with vitrectomy. Diagnoses, operation type, duration of continuous curvilinear capsulorhexis (CCC), number of forceps nips during CCC and capsulorhexis complications were recorded. Five surgeons and four assistants answered a 3D surgery questionnaire.

RESULTS

Twenty-six of 46 patients who underwent 3D surgery, and 31 of 51 patients who underwent traditional microsurgery (control group) were enrolled. The mean CCC duration in the study and control groups was 31.2 ± 10.8 and 28.7 ± 13.2 seconds (p = 0.071), and the mean number of forceps nips was 5 ± 2 and 5 ± 2 (p = 0.634), respectively. The anterior capsular rupture rate of phacoemulsification under 3D and traditional conditions was 3.85% (1/26 cases) and 3.23% (1/31 cases), respectively. The complication rate was similar between the two groups (p > 0.999). Four of five surgeons and two of four assistants believed the clarity of 3D surgery was similar or better than that of traditional microsurgery. The occurrence of dizziness (p > 0.999), shoulder and neck pain (p = 0.262), backache (p = 0.471) and visual fatigue (p = 0.347) did not differ significantly between the two methods.

CONCLUSION

The 3D surgical system facilitated similar operation speed and stability as the traditional microscope and provided reliable support for ophthalmic surgery.

Craniofacial Anthropometry of Healthy Turkish Young Adults: Outer Canthal, Inner Canthal, Palpebral Fissure, and Interpupillary Distances

ABSTRACT

This study aims to examine the values of the orbital region in Turkish young adults by the two-dimensional photogrammetry. Anthropometric measurements of the eye and eyelid-related parameters were taken from 100 female and 100 male volunteer Turkish young adults, ranging in age from 18 to 25 years. Endocanthion (en), exocanthion (ex), and pupil (p) were identified on the photograph and the distances between these points were measured with the ImageJ program. The average values of the en-en, ex-en (R), ex-en (L), p-p, and ex-ex were found as 32.92 ± 2.84, 32.48 ± 2.06, 32.22 ± 2.01, 65.32 ± 3.77, and 97.75 ± 5.09 mm, respectively. There were statistically significant differences between the genders in all parameters. Although there are many studies examining these parameters, comprehensive studies are needed in different populations and in many cases. In this study, we believe that the results obtained for Turkish young adults can be used as reference values.

Effect of Ultra-high-definition Television on Ocular Surface and Fatigue

PURPOSE

To investigate the effects of watching ultra-high-definition television (UHD TV) on subjective ocular fatigue and objective ocular surface indices.

METHODS

A total of 76 volunteers were recruited for this study. Subjects watched UHD TV for 10 minutes at a viewing distance of 110 cm. Best-corrected visual acuity, refractive errors, tear break-up time, corneal staining grading, conjunctival redness grading by slit-lamp examination, tear meniscus measurement by anterior segment optical coherence tomography, and ocular symptom scores were obtained before and immediately after watching UHD TV. Subgroup analyses were conducted according to participant age (old age group >50 years vs. young age group ≤50 years) and dry-eye syndrome (presence vs. absence). The relationship between subjective and objective indices was evaluated.

RESULTS

The mean age of subjects was 39.6 ± 12.4 years. Watching UHD TV induced a decrease in tear break-up time in the non-dry-eye group (p < 0.001) but not in the dry-eye group (p = 0.726). Corneal staining grades increased in all subgroups, and the changes were particularly larger in the older group (p = 0.038). The increase in ocular symptom scores was larger in the dry-eye group (p = 0.08) and in the older group (p = 0.016). The decrease in tear break-up time and ocular symptom scores after watching UHD TV was significantly correlated with tear break-up time.

CONCLUSIONS

Tear break-up time significantly decreased in non-dry-eye subjects after watching UHD TV. Subjective ocular discomfort increased significantly in subjects over the age of 50 and in participants with dry-eye syndrome.

A dichoptic feedback-based oculomotor training method to manipulate interocular alignment

Strabismus is a prevalent impairment of binocular alignment that is associated with a spectrum of perceptual deficits and social disadvantages. Current treatments for strabismus involve ocular alignment through surgical or optical methods and may include vision therapy exercises. In the present study, we explore the potential of real-time dichoptic visual feedback that may be used to quantify and manipulate interocular alignment. A gaze-contingent ring was presented independently to each eye of 11 normally-sighted observers as they fixated a target dot presented only to their dominant eye. Their task was to center the rings within 2° of the target for at least 1 s, with feedback provided by the sizes of the rings. By offsetting the ring in the non-dominant eye temporally or nasally, this task required convergence or divergence, respectively, of the non-dominant eye. Eight of 11 observers attained 5° asymmetric convergence and 3 of 11 attained 3° asymmetric divergence. The results suggest that real-time gaze-contingent feedback may be used to quantify and transiently simulate strabismus and holds promise as a method to augment existing therapies for oculomotor alignment disorders.

Influence of virtual reality on visual parameters: immersive versus non-immersive mode

Abstract

Background

To investigate the differences in refraction, accommodative factors, visual parameters, and subjective symptoms after using two types of virtual reality (VR) content with different depths of perception.

Methods

Twenty-three volunteers, who played VR games in two modes (immersive and non-immersive) for 30 min, were enrolled. Visual parameters were examined before and after using VR. Accommodative factors were measured using static and dynamic methods. Subjective symptoms were assessed using a questionnaire. Differences according to VR content were compared, and correlations between each visual parameter were analyzed.

Results

There were no changes in refraction or accommodative factors after use of the VR. However, there was a significant increase in the near point of accommodation (NPA), the near point of convergence (NPC), and subjective symptom scores after using the immersive mode. Correlation analysis revealed a positive correlation between baseline values of near exophoria and mean accommodative lag of the dominant eye, and also revealed a negative correlation between NPA and mean accommodative lag in the non-dominant eye.

Conclusions

The use of VR for 30 min increased NPA and NPC, especially after the immersive mode was used. In addition, higher exophoria and smaller NPA is associated with increased accommodative lag after using VR.

Comparing Heads-Up versus Binocular Microscope Visualization Systems in Anterior and Posterior Segment Surgeries: A Retrospective Study

BACKGROUND

Three-dimensional (3D) visualization systems, also known as heads-up systems, are now available for eye surgery and as with every new device there is need for a specific evaluation.

OBJECTIVES

The aim of this study was to compare the efficiency, surgical comfort, and safety of a 3D visualization system to a standard binocular microscope (BM) in routine ophthalmologic procedures.

METHOD

After a 4-week training period, a 3D visualization system (Ngenuity, Alcon®) available in one of the Robert Debré Hospital Ophthalmology Departments' operating rooms was compared to a standard BM (OPMI LUMIRA 700, Zeiss®), in the process of a call for new device evaluation. From December 2017 to March 2018, 5 surgeons and their respective residents were asked to fill in a questionnaire for all procedures. Before the surgery, the surgeon recorded: (i) the type of surgery (cataract [PK], retinal detachment [RD], epiretinal membrane peeling [ERM], macular hole, vitreous haemorrhage [VH]), (ii) the type of visualization system chosen (3D or BM), and (iii) the estimated surgical risk (low, intermediate, or high grade). At the end of the procedure, the primary surgeon recorded the remaining parameters, including: (i) surgery duration, (ii) intraoperative complications, (iii) percentage of endoillumination for posterior segment surgeries, (iv) status of the operator (senior or resident) and operator switch if necessary (senior only, resident only, or resident with help of the senior), and rated: (i) the visual comfort (low, normal, excellent), (ii) the operative fluency (low, normal, excellent), (iii) backaches (none, low, moderate, important), and (iv) headaches (range from 0 to 10). Age and sex were collected retrospectively. The procedures performed with 3D and BM were subsequently compared using univariate (χ2, Fisher, Wilcoxon) and multivariate analysis (generalized linear model), allowing us to identify parameters independently associated with PK surgery duration.

RESULTS

A total of 102 valid questionnaires, relative to 73 PK and 29 vitreoretinal procedures, respectively, were analysed. As regards PK (3D, n = 25 vs. BM, n = 48), the mean age, sex ratio, surgical risk, intraoperative complications (1/25 vs. 4/48), visual comfort, backaches, and headaches were similar between the two systems. The use of 3D allowed faster PK surgeries (16.44 ± 4.36 vs. 21.44 ± 7.50 min; p = 0.007) and slightly enhanced the operative fluency. In vitreoretinal surgeries (3D, n = 14 vs. BM, n = 15), no obvious differences between the two visualization systems were observed, although the use of the 3D system was found to slightly decrease the operative fluency. Parameters independently associated with PK surgery duration were 3D visualization (β = -4.4 ± 1.4; p = 0.002), high preoperative surgical risk (β = 6.2 ± 2.4; p = 0.012), intraoperative complications (β = 8.7 ± 2.6; p = 0.001), and surgeon status (β = -4.4 ± 1.3; p = 0.001) in univariate and multivariate analysis.

CONCLUSIONS

3D visualization can be safely used in routine practice. It slightly improves the operative fluency, allowing faster PK surgery.

Utility of digitally assisted vitreoretinal surgery systems (DAVS) for high-volume vitreoretinal surgery centre: a pilot study

AIM

To compare the surgical experience and preferred imaging platform, between digitally assisted vitreoretinal surgery systems (DAVS) and analogue microscope (AM), for performing various surgical manoeuvres.

MATERIAL AND METHODS

A questionnaire was used to evaluate the experience of surgeons who used DAVS for at least 6 months in the last 1 year.

RESULTS

Twenty-three surgeons, including 12 fellows, answered the questionnaire. Eighty-two per cent of surgeons got accustomed to DAVS in <10 surgeries. The higher magnification provided by DAVS was perceived as helpful by 87.0% surgeons. Seventy-eight per cent surgeons felt that DAVS provided a bigger field of view. Colours displayed on DAVS appeared unnatural to 39.1%. Difficulty using three-dimensional glasses over spectacles, asthenopia and dry eye symptoms while using DAVS were faced by 17.4%, 17.4% and 21.7% surgeons, respectively. Difficulty in frequent switching between DAVS and AM was faced by 30.4% surgeons. Difficulty in depth perception, hand-eye coordination and performance anxiety while using DAVS was faced by 43.5%, 21.7 % and 30.4 % surgeons, respectively. Majority consultants did not have any imaging platform preference for most posterior segment procedures, while majority fellows preferred DAVS. Majority surgeons preferred AM for anterior segment procedures and complicated situations like small pupil, corneal oedema and surgical surprise(s). Once the surgeons became accustomed to DAVS, none of them had to shift back to AM during any case.

CONCLUSION

It was easy to adapt to DAVS. DAVS was preferred for performing most posterior segment surgeries. Drawbacks like unnatural colours of the projected image and difficulty in performing anterior segment manoeuvres need to be addressed.

The Preliminary Experiences with Three-Dimensional Heads-Up Display Viewing System for Vitreoretinal Surgery under Various Status

Statement: The current article has not been published elsewhere and has not been submitted simultaneously for publication elsewhere.

PURPOSE

To investigate the preliminary use of three-dimensional (3D) heads-up display (HUD) viewing system for vitreoretinal surgery under various status.

MATERIALS AND METHODS

Nonrandomized case-control study. Consecutive cases to have vitreoretinal surgery under various status were prospectively recruited. Twenty-five-gauge vitrectomy platform and 3D viewing system were used. Main outcomes included: luminous emittance (lux) of endoillumination pipe, surgical duration, the surgeon and residents' preference and ergonomics. Consecutive patients to have vitreoretinal surgery with the conventional viewing system were recruited as control group following the same inclusion and exclusion criteria and underwent surgeries by the same surgeon with the same microscope and vitrectomy platform.

RESULTS

Thirty-one patients (31 eyes; Group Study) and twenty-eight patients (28 eyes; Group Control) were included; without significantly statistical difference in terms of age, gender, main diagnosis, surgical duration, and difficulty rating between both groups (all P > 0.05). Lower endoillumination intensity was needed in Group Study than that in Group Control (10% vs. 35%; 598.7 ± 5.4 vs. 1913.0 ± 12.9 lux, P < 0.001). The surgeon and residents expressed overwhelming preference with the 3D system in both groups. Improved ergonomic was rated in Group Study (4.4 ± 0.8 vs. 3.2 ± 1.0, P < 0.001). Some intraoperative difficulties and discomforts appeared to the surgeon and assistants when using the 3D viewing system.

CONCLUSION

Vitreoretinal surgery under various status can be well finished with the HUD platform by novice at the system. Main benefits included lower endoillumination intensity, enhanced users' preference, and improved ergonomics. Some further refinements of the system are expected.

Comparison of a Three-Dimensional Heads-Up Display Surgical Platform with a Standard Operating Microscope for Macular Surgery

PURPOSE

To assess safety, efficacy, and outcomes of vitreoretinal surgery for macular pathology using a 3-dimensional heads-up display (3D HUD) surgical platform compared with a standard operating microscope (SOM).

DESIGN

Prospective, single-center, unmasked, randomized study.

PARTICIPANTS

Patients undergoing pars plana vitrectomy (PPV) for epiretinal membrane (ERM) or full-thickness macular hole (MH) at Wills Eye Hospital.

METHODS

Patients were randomized 1:1 to undergo surgery with a 3D HUD surgical platform or SOM. Patients who had previous PPV were excluded. Surgical choices, including PPV gauge, were based on surgeon preference. Standard surgical safety parameters, Early Treatment Diabetic Retinopathy Study visual acuity (VA), minimum required endoillumination levels, operative times, and surgeon "ease of use" of the viewing platform were recorded. Patients were followed up to postoperative month 3 (POM3).

MAIN OUTCOME MEASURES

The main outcome measures were total operative time, macular peel time, surgeon rating of viewing system ease of use, minimum required endoillumination, intraoperative complication rate, and postoperative VA.

RESULTS

Thirty-nine eyes of 39 patients with a mean age of 67.60±8.21 SD years were enrolled. Indications included ERM (n = 26 [3D HUD = 14, SOM = 12]) and MH (n = 13 [3D HUD = 9, SOM = 4]). Minimum required endoillumination was significantly lower with 3D HUD (mean 22.70%±15.10% SD) compared with SOM (mean 39.06%±2.72%; P < 0.001). There was no significant difference in overall operative time, but macular peel time was significantly longer using 3D HUD (mean 14.76±4.79 minutes) than SOM (11.87±8.07 minutes; P = 0.004). Surgeon-reported ease of use was significantly higher (easier) using SOM compared with 3D HUD (P = 0.004). There was no statistically significant difference between the groups in POM3 logarithm of the minimum angle of resolution (logMAR) VA or change in logMAR VA from baseline (all P > 0.681). There were no clinically significant intraoperative complications in either group.

CONCLUSIONS

Three-dimensional heads-up display surgical visualization is an evolving technology demonstrating comparable efficacy to the SOM for macular surgery. Although overall surgical times were similar, 3D HUD macular peel times were longer and associated with less ease of use in this study, which may partly be due to a learning curve with new technology.

Evaluation of 3D heads-up vitrectomy: outcomes of psychometric skills testing and surgeon satisfaction

Objectives

To evaluate the use of a three-dimensional heads-up microscope (3DM) during 25-gauge pars plana vitrectomy (PPV) compared with a traditional ophthalmic microscope (TM) in terms of efficacy, safety, and teaching and learning satisfaction.

Methods

Prospective comparative interventional study. Fifty eyes affected by one of the following diseases: rhegmatogenous or tractional retinal detachment, epiretinal membrane, full-thickness macular hole, vitreous hemorrhage, or dropped lens. The 50 eyes were randomly assigned to one of two groups: group A (25 eyes) underwent 25-gauge PPV with 3DM, and group B (25 eyes) underwent 25-gauge PPV with TM. The main outcome measures were the duration of the operation, intraoperative complications, and surgeon and observer satisfaction. A questionnaire was used to assess surgeon satisfaction according to the following parameters: comfort, visibility, image quality, depth perception, simplicity of use, maneuverability, and teaching. A questionnaire to assess observer satisfaction was completed by 20 observers (surgical residents or ophthalmic surgeons).

Results

The degree of satisfaction was higher using 3DM for both surgeons and observers (P < 0.001). The average duration of the operation did not differ significantly between the two methods. No major complications occurred for either method.

Conclusions

PPV with 3DM is more comfortable for the surgeon and poses no substantially greater risk of complications for the patient. The high-definition screen delivers excellent depth perception and better screen parameter control, which results in high-quality surgical performance. 3DM surgery helps to significantly improve teaching and learning intra-operative surgical procedures.

Patient Characteristics and Surgical Approach Impacting Simultaneous to Alternate Prism Cover Test Disparity After Exotropia Surgery: A Quantitative Look at the Difference in Motor Outcomes

PURPOSE

To investigate the relationship between simultaneous prism and cover test (SPCT) and alternate prism and cover test (APCT) outcomes after exotropia surgery, and to identify characteristics associated with significant disparity between them.

METHODS

Review of sensorimotor outcomes 2 to 6 months after exotropia surgery identified patients with alignment documented by both SPCT and APCT at the same examination. Two hundred seventy-four and 319 patients had both measurements recorded at distance and near, respectively. Correlation between the SPCT and APCT and range of APCT when the SPCT measurement was zero were determined. Patient characteristics studied for association with a difference between the SPCT and APCT exceeding known APCT test-retest variability included age, visual acuity, fusion, intermittency, pattern, preoperative and postoperative angle, and treatment with or without medial rectus resection.

RESULTS

SPCT and APCT outcomes were strongly correlated (P < .001), significantly different (P < .001), and linearly related. The percentage of patients who were orthotropic (SPCT = 0) was 76% at distance and 80% at near. Misalignment of 10 prism diopters (PD) or less by the APCT was present in 92% of orthotropic patients at distance and 84% at near. Surgery without medial rectus resection (P = .015), larger preoperative angle (P = .003), intermittent exotropia (P = .028), and postoperative exotropia rather than esotropia (P < .001) were associated with a significant SPCT-APCT difference.

CONCLUSIONS

Although a greater postoperative SPCT-APCT disparity was confirmed for patients with intermittent exotropia, it also independently associated with a larger preoperative deviation and surgery without medial rectus resection. Performing medial rectus resection, a surgeon's prerogative, provides more apparently consistent postoperative alignment characterized by less SPCT-APCT disparity. [J Pediatr Ophthalmol Strabismus. 2017;54(4):222-230.].

HEADS-UP SURGERY FOR VITREORETINAL PROCEDURES: An Experimental and Clinical Study

PURPOSE

To investigate the feasibility of performing vitrectomies while viewing a three-dimensional image on a large display in a heads-up position.

METHODS

Twenty volunteers were compared performing meticulous tasks using the heads-up and the traditional method. Some optical parameters, resolution and depth of field, were measured, and the possibilities of digital image processing were investigated. In addition, routine use of the heads-up method for >400 vitrectomies over 8 months was retrospectively analyzed.

RESULTS

Of note, 91.7% of the volunteers preferred the ergonomics of the heads-up technique. The two methods were judged to be similar regarding speed and ease of microscopic manipulations and sharpness of image. Significantly fewer mistakes were made with the heads-up method. The measured resolution of the eyepieces was approximately twice that of the three-dimensional display, whereas depth of the field was about equal. Electronic amplification of the camera's signal resulted in increased image brightness, allowing use of reduced endoillumination levels. In clinical routine, better ergonomics, digital image processing, and use of a large display are found to be major advantages.

CONCLUSION

The heads-up method is well suited for vitreoretinal surgery. With further technical improvements, the procedure should soon find widespread use.

Visual Discomfort While Viewing Three-dimensional Television as a Screening Tool for Pediatric Eye Diseases in Children

PURPOSE

To investigate the efficacy of evaluating 3D asthenopia and 3D perception difficulty for screening of binocular vision abnormalities in children.

METHODS

Patients aged 6-12 years with abnormal binocularity, including strabismus, amblyopia, and anisometropia, were included. Age-matched normal subjects without any ophthalmologic abnormality other than a refractive error were also recruited. The best-corrected visual acuity, refractive error, angle of strabismus, and stereopsis were measured. Presenting visual acuity (PVA) was measured as the uncorrected visual acuity for subjects without glasses and spectacle-corrected visual acuity for those with glasses. After watching 3D TV for 30 min, a survey was administered to evaluate the 3D perception and 3D asthenopia. Receiver operation characteristic (ROC) curve analysis was conducted to evaluate the efficacy of the survey for detecting abnormal binocularity and poor PVA.

RESULTS

One hundred subjects were enrolled in this study. Among them, 59 had abnormal binocularity (strabismus, anisometropia, or amblyopia), and 41 were normal control. Among the entire subjects, the number of subjects with a PVA of 20/40 or worse in one or both eyes was 24 (7 from the normal control and 17 with abnormal binocularity). ROC curve analysis revealed that the survey did not effectively detect strabismus, anisometropia, or amblyopia. However, for detection of PVA 20/40 or worse in the subjects with abnormal binocularity, the total score of the survey yielded an area of 0.714 under the ROC curve (p = 0.010). The sensitivity was 88.2% and specificity was 61.9% with a cutoff at 0.50.

CONCLUSION

The degree of 3D asthenopia and 3D perception while watching 3D TV were not effective for screening of abnormal binocularity. However, evaluation of the severity of 3D asthenopia and the quality of 3D perception can help screen of decrease in PVA that requires correction.

Evaluation of interpupillary distance in the Turkish population

Purpose

The aim of this study was to report normative values and ranges of interpupillary distance (IPD) in different age groups of a Turkish population.

Methods

A total of 756 healthy subjects were included in this prospective study. After a complete ophthalmic evaluation, subjects were divided into four age groups to assess differences between age groups in relation to IPD. The age groups were 20–30, 31–50, 51–70, and 71–89 years. Far IPD measurements were performed using an autorefractometer (Topcon RM-8800).

Results

The mean age was 48.42±20.55 years, ranging from 19 to 89 years. The mean IPD was calculated as 62.5±4.1 mm (range 49–76). The mean IPD value was observed to be significantly higher among males compared to females (P<0.001). The difference among groups in terms of mean IPD was statistically significant (P<0.001). IPD increased by 4.19 mm in males and 3.11 mm in females from the young adults (20–30 years) to older adults (51–70 years), and then a decrease (2.6 and 0.19 mm for males and females, respectively) occurred between 70 and 89 years of age.

Conclusion

The current study offers the population-specific normative data on far IPD in different age groups. Our study showed that sex and age had a significant effect on IPD. Knowledge of normal values in this population subgroup may be useful in studying orbito-cranial growth patterns, syndrome diagnosis, surgical management of cranio-facial deformities and trauma, and manufactures of optical frames and lenses.

Effect of watching 3-dimensional television on refractive error in children

Purpose

To investigate the effect of watching 3-dimensional (3D) television (TV) on refractive error in children.

Methods

Sixty healthy volunteers, aged 6 to 12 years, without any ocular abnormalities other than refractive error were recruited for this study. They watched 3D TV for 50 minutes at a viewing distance of 2.8 meters. The image disparity of the 3D contents was from -1 to 1 degree. Refractive errors were measured both before and immediately after watching TV and were rechecked after a 10-minute rest period. The refractive errors before and after watching TV were compared. The amount of refractive change was also compared between myopes and controls. The refractive error of the participants who showed a myopic shift immediately after watching TV were compared across each time point to assure that the myopic shift persisted after a 10-minute rest.

Results

The mean age of the participants was 9.23 ± 1.75 years. The baseline manifest refractive error was -1.70 ± 1.79 (-5.50 to +1.25) diopters. The refractive errors immediately after watching and after a 10-minute rest were -1.75 ± 1.85 and -1.69 ± 1.80 diopters, respectively, which were not different from the baseline values. Myopic participants (34 participants), whose spherical equivalent was worse than -0.75 diopters, also did not show any significant refractive change after watching 3D TV. A myopic shift was observed in 31 participants with a mean score of 0.29 ± 0.23 diopters, which resolved after a 10-minute rest.

Conclusions

Watching properly made 3D content on a 3D TV for 50 minutes with a 10-minute intermission at more than 2.8 meters of viewing distance did not affect the refractive error of children.

Why can't my child see 3D television?

A child encountering difficulty in watching three-dimensional (3D) stereoscopic displays could have an underlying ocular disorder. It is therefore valuable to understand the differential diagnoses and so conduct an appropriate clinical assessment to address concerns about poor 3D vision.

Clinical evaluation of accommodation and ocular surface stability relevant to visual asthenopia with 3D displays

Background

To validate the association between accommodation and visual asthenopia by measuring objective accommodative amplitude with the Optical Quality Analysis System (OQAS®, Visiometrics, Terrassa, Spain), and to investigate associations among accommodation, ocular surface instability, and visual asthenopia while viewing 3D displays.

Methods

Fifteen normal adults without any ocular disease or surgical history watched the same 3D and 2D displays for 30 minutes. Accommodative ability, ocular protection index (OPI), and total ocular symptom scores were evaluated before and after viewing the 3D and 2D displays. Accommodative ability was evaluated by the near point of accommodation (NPA) and OQAS to ensure reliability. The OPI was calculated by dividing the tear breakup time (TBUT) by the interblink interval (IBI). The changes in accommodative ability, OPI, and total ocular symptom scores after viewing 3D and 2D displays were evaluated.

Results

Accommodative ability evaluated by NPA and OQAS, OPI, and total ocular symptom scores changed significantly after 3D viewing (p = 0.005, 0.003, 0.006, and 0.003, respectively), but yielded no difference after 2D viewing. The objective measurement by OQAS verified the decrease of accommodative ability while viewing 3D displays. The change of NPA, OPI, and total ocular symptom scores after 3D viewing had a significant correlation (p < 0.05), implying direct associations among these factors.

Conclusions

The decrease of accommodative ability after 3D viewing was validated by both subjective and objective methods in our study. Further, the deterioration of accommodative ability and ocular surface stability may be causative factors of visual asthenopia in individuals viewing 3D displays.

Influence of stereopsis and abnormal binocular vision on ocular and systemic discomfort while watching 3D television

PURPOSE

To evaluate the degree of three-dimensional (3D) perception and ocular and systemic discomfort in patients with abnormal binocular vision (ABV), and their relationship to stereoacuity while watching a 3D television (TV).

METHODS

Patients with strabismus, amblyopia, or anisometropia older than 9 years were recruited for the ABV group (98 subjects). Normal volunteers were enrolled in the control group (32 subjects). Best-corrected visual acuity, refractive errors, angle of strabismus, and stereoacuity were measured. After watching 3D TV for 20 min, a survey was conducted to evaluate the degree of 3D perception, and ocular and systemic discomfort while watching 3D TV.

RESULTS

One hundred and thirty subjects were enrolled in this study. The ABV group included 49 patients with strabismus, 22 with amblyopia, and 27 with anisometropia. The ABV group showed worse stereoacuity at near and distant fixation (P<0.001). Ocular and systemic discomfort was, however, not different between the two groups. Fifty-three subjects in the ABV group and all subjects in the control group showed good stereopsis (60 s of arc or better at near), and they reported more dizziness, headache, eye fatigue, and pain (P<0.05) than the other 45 subjects with decreased stereopsis. The subjects with good stereopsis in the ABV group felt more eye fatigue than those in the control group (P=0.031). The subjects with decreased stereopsis showed more difficulty with 3D perception (P<0.001).

CONCLUSIONS

The subjects with abnormal stereopsis showed decreased 3D perception while watching 3D TV. However, ocular and systemic discomfort was more closely related to better stereopsis.