Effects of persistent viewing of 3 D TV on human visual function

目的:研究持续观看3D电视对视功能的影响,以及探索不同视功能参数之间的关系.方法:本研究录入19位受试者,每位受试者观看90分钟的2 D电视或90分钟的3 D电视,两部电视观看间隔时间为一周,顺序随机.每次观看电视前及观看后15 min内都做相关视功能检查,检查包括以下四种视功能参数:调节功能(调节反应、调节微波动、调节灵敏度、正相对调节、负相对调节、AC/A),融像性聚散功能(远距负融像性聚散功能、远距正融像性聚散功能、近距负融像性聚散功能、近距正融像性聚散功能),隐斜量(远距隐斜量、近距隐斜量),立体视.结果:无论是与观看前的基础值比较,还是与观看2D电视后的数据比较,观看3D电视后近距离调节反应增加,汇聚减少,远距隐斜量向外隐斜改变(P<0.05).结论:持续观看3D电视会对人们的视功能有一定影响,主要是打破了调节和聚散系统的平衡.厂家和公众应该引起重视,将调节功能、融像性聚散功能、隐斜量等参数作为评估3D电视安全性的指标.     

Vergence adaptation in clinical vergence testing

BackgroundThe purposes of this investigation were to determine whether vergence adaptation occurs after vergence range testing and vergence facility testing and to determine whether vergence adaptation correlates with the results of these tests.MethodsThirty subjects participated in 3 testing sessions on different days. During each session 1 of the following was tested: base-out prism bar vergences, vergence facility (12 base-out/3 base-in binocular prism flippers for 1 minute), and 5 minutes viewing with 6 prism diopters of base-out prism. Before and after each test, the near phoria was measured using the modified Thorington method.ResultsThere was no correlation between the amplitude of the vergence ranges and the amplitude of vergence facility. Significant vergence adaptation as indicated by an esophoric shift of approximately 3 prism diopters occurred in all testing sessions. The amplitude of vergence adaptation did not correlate with either the amplitude of the blur vergence range or vergence facility. There was a significant correlation between the amplitude of vergence adaptation and the amplitude of the break vergence range.ConclusionsThe lack of correlation between the blur vergence range and the vergence facility is not likely because of vergence adaptation. The lack of correlation between the break vergence range and the vergence facility may be in part caused by vergence adaptation.     

Distance vergence adaptation is abnormal in subjects with convergence insufficiency

It is well known that in convergence insufficiency (CI) prism adaptation is reduced in response to base-out (BO) prisms at near. There have also been some suggestions in the literature that adaptation is reduced at other distances as well. The present data show that in CI adaptation is not only reduced in response to BO at near, but also in response to base-in (BI) at near and for both BI and BO at distance. This raises the interesting question whether distance adaptation becomes reduced because of reduced near adaptation or whether these subjects have a generally reduced horizontal adaptation mechanism.     

The Convergence Insufficiency Treatment Trial: Design,Methods, and Baseline Data

Objective: This report describes the design and methodology of the Convergence Insufficiency Treatment Trial (CITT), the first large-scale, placebo-controlled, randomized clinical trial evaluating treatments for convergence insufficiency (CI) in children. We also report the clinical and demographic characteristics of patients. Methods: We prospectively randomized children 9 to 17 years of age to one of four treatment groups: 1) home-based pencil push-ups, 2) home-based computer vergence/accommodative therapy and pencil push-ups, 3) office-based vergence/accommodative therapy with home reinforcement, 4) office-based placebo therapy. Outcome data on the Convergence Insufficiency Symptom Survey (CISS) score (primary outcome), near point of convergence (NPC), and positive fusional vergence were collected after 12 weeks of active treatment and again at 6 and 12 months posttreatment. Results: The CITT enrolled 221 children with symptomatic CI with a mean age of 12.0 years (SD = +2.3). The clinical profile of the cohort at baseline was 9Δ exophoria at near (+/? 4.4) and 2Δ exophoria (+/?2.8) at distance, CISS score = 30 (+/?9.0), NPC = 14 cm (+/? 7.5), and near positive fusional vergence break = 13 Δ (+/? 4.6). There were no statistically significant nor clinically relevant differences between treatment groups with respect to baseline characteristics (p > 0.05).Conclusion: Hallmark features of the study design include formal definitions of conditions and outcomes, standardized diagnostic and treatment protocols, a placebo treatment arm, masked outcome examinations, and the CISS score outcome measure. The baseline data reported herein define the clinical profile of those enrolled into the CITT.     

Oculocardiac reflex in phacoemulsification: Peribulbar vs topical anesthesia

Purpose:This study compares the vital parameters and pain experienced during phacoemulsification under peribulbar and topical anesthesia to determine the incidence of OCR.Methods:One hundred six patients are enrolled for phacoemulsification in a prospective and randomized study. Fifty-two patients undergo surgery in a peribulbar block (Group PB) and 54 in topical anesthesia (Group TA). Mean arterial pressure (MAP) and pulse rate are recorded during a preoperative check-up and at four other steps of surgery. Pain experienced during surgery and on a postoperative day, 5, is graded with a verbal analogue scale. OCR defined as a decrease in pulse rate by greater than 20% is calculated. Chi-square test, Fisher‘s exact test, paired t test and the comparison of means give the statistical analysis. A value of P < 0.05 was taken as significant.Results:MAP readings at baseline versus MAP at other steps of surgery show a trend towards rising with a P value of < 0.05 in both groups. Pulse rate measured at all steps of surgery versus baseline pulse rate in Group TA shows P < 0.05. OCR is present in nine patients in peribulbar block verses eleven patients in topical anesthesia with P value of 0.687. The pain scores using verbal analogue scale were higher in Group TA compared with Group PB with a P < 0.0001.Conclusion:Oculocardiac reflex can occur during phacoemulsification under both peribulbar block and topical anesthesia, and the difference is not significant.     

Longitudinal Macular Retinal and Choroidal Microvasculature Changes in High Myopia

PurposeThe purpose of this study was to determine the longitudinal changes in macular retinal and choroidal microvasculature in normal healthy and highly myopic eyes.MethodsSeventy-one eyes, including 32 eyes with high myopia and 39 healthy control eyes, followed for at least 12 months and examined using optical coherence tomography angiography imaging in at least 3 visits, were included in this study. Fovea-centered 6 × 6 mm scans were performed to measure capillary density (CD) of the superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC). The rates of CD changes in both groups were estimated using a linear mixed model.ResultsOver a mean 14-month follow-up period, highly myopic eyes exhibited a faster rate of whole image CD (wiCD) loss (−1.44%/year vs. −0.11%/year, P = 0.001) and CD loss in the outer ring of the DCP (−1.67%/year vs. –0.14%/year, P < 0.001) than healthy eyes. In multivariate regression analysis, baseline axial length (AL) was negatively correlated with the rate of wiCD loss (estimate = −0.27, 95% confidence interval [CI] = −0.48 to −0.06, P = 0.012) and CD loss in the outer ring (estimate = −0.33, 95% CI = −0.56 to −0.11, P = 0.005), of the DCP. The CD reduction rates in the SCP and CC were comparable in both groups (all P values > 0.05).ConclusionsThe rate of CD loss in the DCP is significantly faster in highly myopic eyes than in healthy eyes and is related to baseline AL. The CD in the outer ring reduces faster in eyes with longer baseline AL.     

Dietary associations with diabetic retinopathy—A cohort study

Purpose:To assess the role of dietary factors in the development of diabetic retinopathy (DR) in diabetics.Methods:This prospective study was carried out on patients attending the outpatient department of ophthalmology for a period of 1 year. An interview-based 24-hour diet recall was used to document average daily dietary nutrient intakes. Each patient was subjected to a comprehensive ocular examination to look for DR.Results:A total of 261 patients attending the outpatient department of ophthalmology were the participants for this study. The mean (±SD) age of the participants was 57.73 ± 11.29 years, and 67% were men. One hundred and six participants had DR. Univariate analysis revealed sex, duration, fish (times/week), egg (yes/no), rice lunch (yes/no), rice dinner, rice (boiled/white), and total calorie intake to be associated with DR (P < 0.05). Logistic regression multivariable analysis revealed males (OR: 3.20, 95% CI: 1.65–6.19), longer duration of diabetes (OR:1.05,95% CI:1.01-1.11), antioxidant intake (OR: 3.42, 95% CI: 1.65–7.05), and consumption of rice (OR: 3.19, 95% CI: 1.17–8.69) to have significant association with DR (P < 0.05), with the odds of developing DR increasing three times in these patients. The odds of developing DR were lesser with more frequent (>2 times/week) fish consumption (OR: 0.42, 95% CI: 0.18–0.94) and in patients on pharmacological treatment for diabetes mellitus (OR: 0.16, 95% CI: 0.04–0.58). Binary logistic regression revealed chapathi consumption (OR: 9.37, 95% CI: 1.64–53.68) to be associated with severe forms and fish consumption (OR: 0.06, 95% CI: 0.01–1.06) (P < 0.05) to be associated with less severe forms of DR.Conclusion:Males, longer duration of diabetes, antioxidant intake, fish consumption, and consumption of rice were associated with the occurrence of DR. Participants with diabetes who consumed fish more frequently and those who were on pharmacological treatment for diabetes mellitus had a significantly lower risk of DR and frequent fish consumption could reduce the risk of DR progression.     

Effect of heterophoria type and myopia on accommodative and vergence responses during sustained near activity in children

The influence of phoria-type and myopia on changes to vergence and accommodation during prolonged near-task was examined in 53 children. Participants were classified into phoria and refractive categories based on near phoria and cycloplegic refraction respectively. Measures of near phoria, binocular (BA) and monocular accommodation (MA) were obtained before and during a 20 min task when children binocularly fixated a high-contrast target at 33 cm through best corrective lenses. Vergence adaptation and accommodative adaptation were quantified using changes to near phoria and tonic accommodation respectively. The direction and magnitude of vergence adaptation was modified by the phoria-type (p < 0.001). Emmetropic exophores displayed convergent (less exo than baseline) adaptation while esophores showed divergent shifts (less eso than baseline) in phoria upon prolonged fixation. Myopic children also followed a similar pattern but showed greater divergent (or less convergent) shift (p < 0.001) in vergence adaptation for all phoria categories compared to emmetropes. Phoria-type also influenced the pattern of BA vs. MA (p < 0.001) such that exophores showed BA > MA while esophores showed MA > BA in both refractive groups. Accommodative adaptation was higher in myopes (p = 0.010) but did not demonstrate a significant effect of phoria (p = 0.4). The influence of phoria-type on vergence adaptation and the pattern of BA vs. MA relates primarily to the varying fusional vergence demands created by the direction of phoria. The greater divergent (or less convergent) shift in vergence adaptation seen in myopes (compared to emmetropes) could be attributed to their higher accommodative adaptation. Nevertheless, the adaptive patterns observed in myopic children do not appear to explain their high response AV/A ratios identified as a risk factor for myopia development.     

Extrinsic and Intrinsic Factors Regulating Juvenile Refractive Development and Eye Growth

PurposePeripheral refraction and accommodation are intrinsic factors that were once hypothesized to trigger myopia but are now controversial. Previously, home nearwork environment (i.e., extrinsic factor) was reported to be associated with myopia progression. In this study, we aimed to evaluate the potential interaction between extrinsic and intrinsic factors with juvenile refractive development.MethodsNearwork environmental parameters were measured for 50 children (aged 9.3 ± 1.2 years), including net amount and dispersion of defocus. Refraction was measured at near distances and in central field (±30° horizontal) at 3m. The relative peripheral refraction (RPRE) was obtained and presented in a vectoral approach. The linear regression coefficient was extracted (m_Acc) from the accommodative stimulus–response curve. RPRE was quadratically regressed against field eccentricity, and the first coefficients (a_M, a_J0, a_P90, and a_P180) were extracted. Relationships between RPRE, baseline accommodation, and 1-year myopia progression (∆M), controlled for the nearwork environment, were evaluated.ResultsCoefficients of RPRE were independent of ∆M. However, additional nearwork environmental parameters significantly improved the variance in ∆M explained by a_M and a_P180 (P < 0.03). The relationship between intrinsic factor and ∆M was stronger when the extrinsic risk was low (P ≤ 0.01), whereas the relationship was abolished when extrinsic risk was high. For m_Acc, it also significantly improved the variance in ∆M explained by nearwork environmental parameters.ConclusionsThe interaction between extrinsic (environment) and intrinsic (RPRE and accommodation) factors is speculated to contribute to juvenile myopia progression. Our findings may also explain the inconsistencies of such intrinsic factors in the literature.     

Palpebral Fissure Response to Phenylephrine Indicates Autonomic Dysfunction in Patients With Type 1 Diabetes and Polyneuropathy

PurposeThe superior and inferior tarsal muscles are sympathetically innervated smooth muscles. Long-term diabetes often leads to microvascular complications, such as, retinopathy and autonomic neuropathy. We hypothesized that diabetes induces (1) sympathetic paresis in the superior and inferior tarsal muscles and that this measure is associated with (2) the severity of diabetic retinopathy, (3) the duration of diabetes, and (4) autonomic function. In addition, association between the severity of retinopathy and autonomic function was investigated.MethodsForty-eight participants with long-term type 1 diabetes and confirmed distal symmetrical polyneuropathy were included. Palpebral fissure heights were measured bilaterally in response to topically applied 10% phenylephrine to the right eye. The presence of proliferative diabetic retinopathy (PDR) or nonproliferative diabetic retinopathy and disease duration were denoted. Time and frequency derived heart rate variability parameters obtained from 24-hour continuous electrocardiography were recorded.ResultsThe difference in palpebral fissure heights between phenylephrine treated and untreated eyes (∆PFH) was 1.02 mm ± 0.29 (P = 0.001). The ∆PFH was significantly lower in the PDR group (0.41 mm ± 0.43 vs. 1.27 mm ± 1.0), F(1,35) = 5.26, P = 0.011. The ∆PFH was lower with increasing diabetes duration, r(37) = −0.612, P = 0.000. Further, the ∆PFH was lower with diminished autonomic function assessed as total frequency power in electrocardiogram (r = 0.417, P = 0.014), and sympathetic measures of very low (r = 0.437, P = 0.010) and low frequency power (r = 0.384, P = 0.025).ConclusionsThe ∆PFH is a simple ambulatory sympathetic measure, which was associated with the presence of PDR, disease duration, and autonomic function. Consequently, ∆PFH could potentially be an inexpensive and sensitive clinical indicator of autonomic dysfunction.     

Half Minimally Invasive Strabismus Surgery (MISS): A single para-muscular approach to horizontal muscle strabismus surgery

Purpose:Minimally invasive surgeries are gaining popularity. We compared two different approaches to rectus muscles: namely the standard para limbal (SPL) and the single para-muscular (SPM).Methods:Thirty-six patients planned for monocular horizontal strabismus surgery were block randomized to SPL and SPM approach. SPM approach involved a single para-muscular 10-mm conjunctival incision levelled at the inferior border of rectus muscle. We compared the post-operative grades of redness, congestion, chemosis, foreign body sensation, and drop intolerance at day 1, 2 weeks, and 6–8 weeks; scar visibility and success rates at 6–8 weeks and operation duration in minutes. We compared the results using Mann–Whitney U-test for inflammatory grades, Fisher’s exact test for proportions, and t-test for parametric measures. Significance was set at P < 0.05.Results:On postoperative follow-up at any time point, no significant difference was found on comparing inflammatory grades, scar visibility, and success rates. In terms of duration, SPL approach was on an average 21.5 minutes quicker than SPM (P = <0.001).Conclusion:The SPM is comparable to the SPL approach in terms of postoperative comfort and appearance, but takes significantly longer to accomplish.     

Collateral Vessel Development in Central and Branch Retinal Vein Occlusions Are Associated With Worse Visual and Anatomic Outcomes

PurposeThe purpose of this study was to investigate the effects of the extension of collateral vessels on the outcomes of eyes affected by central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO).MethodsThe study was designed as a cross-sectional case series. Patients affected by CRVO and BRVO were progressively recruited, along with an age- and sex-matched control group of healthy subjects. Structural optical coherence tomography (OCT) and OCT angiography (OCTA; 4.5 × 4.5 mm and 9.0 × 9.0 mm acquisitions) were performed on all participants in order to assess the relationship between the presence of collateral vessels and final anatomical outcomes – central macular thickness (CMT), foveal avascular zone – and functional outcomes – best corrected visual acuity (BCVA).ResultsFifty-six eyes affected by CRVO and 47 eyes affected by BRVO were included. Baseline LogMAR BCVA was 0.41 ± 0.33 LogMAR in CRVO, and 0.39 ± 0.25 LogMAR in BRVO (P < 0.01), improving to 0.20 ± 0.26 LogMAR in CRVO (P < 0.01), and 0.19 ± 0.22 LogMAR in BRVO (P < 0.01). Baseline CMT was 511 ± 214 µm in CRVO and 482 ± 178 µm in BRVO (P > 0.05), decreasing to 328 ± 105 µm (P < 0.01) and 321 ± 78 µm in CRVO and BRVO, respectively (P < 0.01). Collateral vessels were detected in 16 of 56 eyes (29%) in CRVO and in 47 of 47 eyes (100%) in BRVO. Their extension was correlated with worse anatomic and visual outcomes. Remarkably, no correlation was found with peripheral capillary nonperfusion and vessel density impairment.ConclusionsThe present study demonstrates that collateral vessel extension is associated with worse anatomic and functional outcomes in patients affected by CRVO and BRVO.     

Comparison of effective phacoemulsification time and corneal endothelial cell loss using three different ultrasound frequencies: A randomized controlled trial

Purpose:Comparison of three ultrasound (US) frequencies for phacoemulsification of hard cataracts to determine a frequency that makes phacoemulsification more efficacious and safer.Methods:A randomized controlled trial was undertaken at a medical college and hospital. In total, 207 patients with grade 5.6–6.9 (LOCS III) senile cataract were randomized into three groups. Group I underwent phacoemulsification with 28-kHz frequency, group II with 42-kHz frequency, and group III with 53-kHz frequency. The effective phacoemulsification time (EPT) and estimated fluid usage (EFU) were compared intraoperatively. The endothelial cell parameters were analyzed for 6 months.Results:The groups were matched for age (P = 0.467), gender (P = 0.497), nuclear grade (P = 0.321), and anterior chamber depth (P = 0.635). The EPT and EFU were significantly lower in group III, compared to group II and group I, with P < 0.0001 and P < 0.0001, respectively. Postoperatively, the endothelial cell density (ECD) was significantly higher in group III at 1 month (P < 0.0001), 3 months (P < 0.0001), and 6 months (P < 0.0001). The percentages of ECD loss were also significantly lower in group III; the difference was statistically significant (P < 0.0001) up to 6 months postoperativelyConclusion:Higher frequency ultrasound was associated with a lower EPT and EFU as well as better endothelial preservation than lower frequencies in hard cataracts.     

Corneal Keratocyte Density and Corneal Nerves Are Reduced in Patients With Severe Obesity and Improve After Bariatric Surgery

PurposeObesity is associated with peripheral neuropathy, which bariatric surgery may ameliorate. The aim of this study was to assess whether corneal confocal microscopy can show a change in corneal nerve morphology and keratocyte density in subjects with severe obesity after bariatric surgery.MethodsTwenty obese patients with diabetes (n = 13) and without diabetes (n = 7) underwent assessment of hemoglobin A1c (HbA1c), lipids, IL-6, highly sensitive C-reactive protein (hsCRP), and corneal confocal microscopy before and 12 months after bariatric surgery. Corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL), and keratocyte density (KD) from the anterior, middle, and posterior stroma were quantified. Twenty-two controls underwent assessment at baseline only.ResultsCNFL (P < 0.001), CNBD (P < 0.05), and anterior (P < 0.001), middle (P < 0.001), and posterior (P < 0.001) keratocyte densities were significantly lower in obese patients compared to controls, and anterior keratocyte density (AKD) correlated with CNFL. Twelve months after bariatric surgery, there were significant improvements in body mass index (BMI; P < 0.001), HDL cholesterol (P < 0.05), hsCRP (P < 0.001), and IL-6 (P < 0.01). There were significant increases in CNFD (P < 0.05), CNBD (P < 0.05), CNFL (P < 0.05), and anterior (P < 0.05) and middle (P < 0.001) keratocyte densities. The increase in AKD correlated with a decrease in BMI (r = –0.55, P < 0.05) and triglycerides (r = –0.85, P < 0.001). There were no significant correlations between the change in keratocyte densities and corneal nerve fiber or other neuropathy measures.ConclusionsCorneal confocal microscopy demonstrates early small fiber damage and reduced keratocyte density in obese patients. Bariatric surgery leads to weight reduction and improvement in lipids and inflammation and an improvement in keratocyte density and corneal nerve regeneration.     

Bilateral Limbal Stem Cell Alterations in Patients With Unilateral Herpes Simplex Keratitis and Herpes Zoster Ophthalmicus as Shown by In Vivo Confocal Microscopy

PurposeThe purpose of this study was to investigate the limbal changes in the palisades of Vogt (POV) in patients with herpes simplex keratitis (HSK) and herpes zoster ophthalmicus (HZO) with the application of in vivo confocal microscopy (IVCM).MethodsWe enrolled 35 eyes of 35 consecutive patients with HSK and 4 patients with HZO in this observational study. Thirty-five participants were also recruited from a healthy population as the control group. All subjects were examined by IVCM in addition to routine slit-lamp biomicroscopy. The IVCM images of the corneal basal epithelial cells, corneal nerve, and the corneoscleral limbus were acquired and then were analyzed semiquantitatively.ResultsThe rate of absent and atypical POV was significantly higher in the affected eyes of patients with HSK than in the contralateral eyes and eyes of controls (88.57% vs. 65.71% vs. 17.14%, P < 0.01). In the HZO group, the rate of absent and atypical POV was 100% in the affected eyes and 50% in the contralateral eyes. When compared to the contralateral unaffected eyes and control eyes, the average density of the central basal epithelial cells and the sub-basal nerve plexus density and the total number of nerves in the central area of the affected eyes were significantly lower in the HSK group (1541 ± 704.4 vs. 2510 ± 746.8 vs. 3650 ± 746.1 cells/mm², P < 0.0001). Spearman''s rank correlation showed that the presence of absent and atypical POV had a significant negative correlation with central corneal basal epithelial cells (r_s = −0.44979, P < 0.0001), the density of total nerves (r_s = −0.49742, P < 0.0001), and the total nerve numbers (r_s = −0.48437, P < 0.0001). A significant positive correlation was established between the presence of absent and atypical POV and HSK severity in affected eyes in the superior, inferior, nasal, and temporal quadrants (r_s = 0.68940, r_s = 0.78715, r_s = 0.65591, and r_s = 0.75481, respectively, P < 0.0001) and the contralateral eyes (r_s = 0.51636, r_s = 0.36207, r_s = 0.36990, r_s = 0.51241, correspondingly, P < 0.0001).ConclusionsBoth eyes of patients with unilateral HSK and HZO demonstrated a profound and significant loss of limbal stem cells, which may explain the fact that HSK and HZO are risk factors for limbal stem cell deficiency (LSCD) in both eyes. The loss of LSCs was strongly correlated with the sub-basal nerve plexus and central basal epithelial cell alterations as shown by IVCM.     

The forced vergence cover test and phoria adaptation

Phoria adaptation (PA) provides innervation to help maintain the correct vergence posture for binocularly viewing objects. Once fusion is disrupted, such as is required for measuring a (dissociated) phoria, this innervation is slowly depleted. Thus, extended periods of monocular occlusion can be required to dissipate PA and reveal the full extent of the phoria. Two versions of a forced vergence modification of the alternating cover test (CT) have been proposed to rapidly show the full phoria. We evaluated the ability of these forced vergence CTs (FVCT-1 and FVCT-2) to deplete the PA induced by a 15 min adaptation period to base out prism. In both experiments, the CT followed by the FVCT was performed before and after the adaptation period. In Experiment 1 (n = 13), the FVCT-1 was evaluated at 40 cm. Experiment 2 (n = 32) evaluated the FVCT-2 at 4 m. In Experiments 1 and 2, the difference between pre- and post-adaptation CTs showed significant PA occurred during the adaptation period (7.8(Delta), p < 0.0005, and 5.4(Delta), p < 0.0005 respectively). In Experiment 1, the FVCT-1 did not reveal a larger phoria than the CT before (mean difference: 0.4(Delta), p = 0.34) or after (no difference for all subjects) the adaptation period. Thus, the FVCT-1 did not alter PA. In Experiment 2, the FVCT-2 did show a shift in the phoria compared to the CT. However, this shift was found to be equivalent before and after the adaptation period (mean difference in shift: 0.22(Delta), 95% CI: -0.52 to 0.96(Delta)). Thus, the FVCT-2 shifts the phoria a constant amount independent of the amount of PA present. We conclude that neither FVCT's behaviour is dependent on the PA present. Thus, these procedures are unlikely to be effective clinical procedures for revealing the full magnitude of the phoria.     

Visual impairment and ten-year mortality: the Liwan Eye Study

ObjectivesTo explore associations between visual impairment (VI) and mortality in an adult population in urban China.MethodsThe Liwan Eye Study was a population-based prevalence survey conducted in Guangzhou, Southern China. The baseline examination was carried out in 2003. All baseline participants were invited for the 10-year follow-up visit. VI was defined as the visual acuity of 20/40 or worse in the better-seeing eye with habitual correction if worn. Correctable VI was defined as the VI correctable to 20/40 or better by subjective refraction, and non-correctable VI was defined as the VI correctable to worse than 20/40. Mortality rates were compared using the log-rank test and Cox proportional hazards regression models.ResultsOf the 1399 participants (mean age: 65.3 ± 9.93 years; 56.4% female) with available baseline visual acuity measurement, 320 participants (22.9%) had VI. After 10 years, 314 (22.4%) participants died. Visually impaired participants had a significantly increased 10-year mortality compared with those without VI (40.0% vs. 17.2%, P < 0.05). After adjusting for age, gender, income, educational attainment, BMI, history of diabetes and hypertension, both VI (HR, 1.55; 95% CI, 1.14–2.11) and non-correctable VI (HR, 2.72; 95% CI, 1.86–3.98) were significantly associated with poorer survival, while correctable VI (HR, 0.99; 95% CI, 0.66–1.49) was not an independent risk factor for 10-year mortality.ConclusionsOur findings that VI, particularly non-correctable VI, predicting poorer survival may imply the underlying mechanism behind VI-mortality association and reinforce the importance of preventing and treating disabling ocular diseases to prevent premature mortality in the elderly.Subject terms: Vision disorders, Risk factors     

Preferred practice pattern and observed outcome of deep anterior lamellar keratoplasty – A survey of Indian corneal surgeons

Purpose:This study aimed to assess the preferred surgical technique and outcome of deep anterior lamellar keratoplasty (DALK) among corneal surgeons in India.Methods:An online questionnaire-based cross-sectional survey was conducted among members of the Cornea Society of India (CSI) with experience of performing >10 DALK procedure. The responses pertaining to their surgical experience, preferred technique, complications, and outcome of DALK were collected and analyzed.Results:A total of 156 responses were received. In total, 35.9% of participants reported annual keratoplasty of >50, and DALK constituted >25% surgeries for 25% of participants. Ectatic corneal disorder was reported as the most common indication for DALK by 71.6% of the respondents. Big-bubble (BB) DALK (W_A-1.82) was the most preferred technique, along with suction trephine (50%) for partial trephination and bottom port cannula (45.5%) for BB formation. On statistical analysis, no difference was observed in the surgeon reported success rate of BB formation with or without anterior lamellar keratectomy (ALK) (χ2 (1,156) = 3.1498, P = 0.08) or paracentesis (χ2 (1,156) = 0.2737, P = 0.60) before stromal air injection, and method of stromal air injection (χ2 (1,156) = 4.7325, P = 0.09). Conversion to penetrating keratoplasty was reported by 16% of participants in >25% cases, while 66.7% reported in <10% cases. Cataract and double anterior chamber were the most common complications. 50% of participants suggested that >20 procedures are required to overcome the learning curve.Conclusion:BB DALK is the most commonly practiced DALK technique, and its success is independent of ALK and paracentesis being performed prior to air injection and method of air injection (cannula/needle).     

Vergence Exercises for Six Weeks Induce Faster Recovery of Convergence Insufficiency Than Accommodation Exercises in School Children

PurposeConvergence insufficiency (CI) is characterized by abnormal vergence eye movement frequently accompanied by abnormal accommodation and subjective symptoms, such as headache, blurred vision, and diplopia. CI is treated with vergence and accommodation exercises that are integrated so that the relative contributions of vergence and accommodation exercises to the outcome are concealed. The purpose of the present study was to determine the individual contributions of vergence and accommodation exercises for the treatment of CI in school children.MethodsIn a prospective crossover study 44 children aged 9 to 13 years with CI were randomized to perform either vergence exercises followed by accommodation exercises each for 6 weeks or the 2 treatment regimes in the reverse order. The outcome measures were recovery from CI and the parameters vergence facility, positive fusional vergence, near point of convergence, monocular amplitude, and facility of accommodation.ResultsAfter the first 6-week period, full recovery from CI was significantly more frequent in the group commencing vergence exercises than in the group commencing monocular accommodation exercises (p = 0.01), whereas there was no significant difference between these proportions after the second 6-week period (p = 0.45). Vergence facility and positive fusional vergence improved significantly more after the period with vergence exercises than after the accommodation exercises, whereas there was no significant difference between the effects of the two types of exercises on the other studied parameters.ConclusionsVergence treatment induces a faster recovery of CI than accommodation treatment in school children. This may be used to improve compliance and success rate of the treatment.     

Long-term visual and treatment outcomes of whole-population pre-school visual screening (PSVS) in children: a longitudinal,retrospective, population-based cohort study

BackgroundThis study reports the long-term visual and treatment outcomes in a whole-population, orthoptic-delivered pre-school visual screening (PSVS) programme in Scotland and further examines their associations with socioeconomic backgrounds and home circumstances.MethodsRetrospective case review was conducted on 430 children who failed PSVS. Outcome measures included best corrected visual acuity (BCVA), severity of amblyopia (mild, moderate and severe), binocular vision (BV) (normal, poor and none), ophthalmic diagnosis and treatment modalities. Parameters at discharge were compared to those at baseline and were measured against the Scottish index of multiple deprivation (SIMD) and Health plan indicator (HPI), which are indices of deprivation and status of home circumstances.ResultsThe proportion of children with amblyopia reduced from 92.3% (373/404) at baseline to 29.1% (106/364) at discharge (p < 0.001). Eighty percent (291/364) had good BV at discharge compared to 29.2% (118/404) at baseline (p < 0.001). Children from more socioeconomically deprived areas (OR 2.19, 95% CI 1.01–4.30, p = 0.003) or adverse family backgrounds (OR 3.94, 95% CI 1.99–7.74, p = 0.002) were more likely to attend poorly and/or become lost to follow-up. Children from worse home circumstances were five times more likely to have residual amblyopia (OR 5.37, 95% CI 3.29–10.07, p < 0.001) and three times more likely to have poor/no BV (OR 3.41, 95% CI 2.49–4.66, p < 0.001) than those from better home circumstances.ConclusionsOrthoptic-delivered PSVS is successful at screening and managing amblyopia. Children from homes requiring social care input are less likely to attend and are more likely to have poorer visual outcomes.Subject terms: Vision disorders, Refractive errors, Ocular motility disorders, Paediatrics, Health care economics