Near Vision Research Articles

Comparatively analysing the postoperative optical performance of different intraocular lenses: a prospective observational study

BackgroundPostoperative performance, including best corrected distance visual acuity (BCDVA) and optical metrics (from the OQAS and iTrace devices), was compared among 4 different intraocular lenses (IOLs).MethodsThis prospective observational study included 104 eyes from 104 subjects who underwent cataract surgery combined with implantation of 4 different IOLs: monofocal (Mon) IOLs, segmental refractive (SegRef) IOLs, diffractive (Dif) IOLs and extended depth of focus (EDoF) IOLs. Postoperative BCDVA and optical metrics were collected at the 6th month. The OQAS optical metrics included the objective scattering index (OSI), Strehl ratio (SR), modulation transfer function (MTF) cut-off frequency, and predicted visual acuity (PVA); the iTrace optical metrics included blur/double vision, glare/halo, starburst, mixed focus, night myopia, and night hyperopia.ResultsThere was no significant difference in BCDVA among the 4 groups (P = 0.059; power = 70.3%). Differences were observed in all OQAS optical metrics among the groups (all P < 0.001). Overall, Mon IOLs and EDoF IOLs exhibited better performance than Dif IOLs and SegRef IOLs. Starburst was the only iTrace optical metric that differed among the groups (P < 0.001): SegRef IOLs caused more starbursts than Mon IOLs (P = 0.001), Dif IOLs (P = 0.006) and EDoF IOLs (P < 0.001). Spearman rank correlation analysis was used to determine the relationships among the iTrace optical metrics, OQAS optical metrics and BCDVA: starburst was negatively correlated with BCDVA, PVA at contrasts of 100% and 20%, OSI, and MTF cut-off frequency (all P ≤ 0.001); mixed focus was positively correlated with BCDVA, PVA at contrasts of 100% and 20%, OSI, and MTF cut-off frequency (all P ≤ 0.001).ConclusionsPostoperative BCDVA and optical metrics varied among the different IOLs, which should be taken into account in the selection and management of IOLs for cataract patients.Trial registrationThis study was approved by the First Affiliated Hospital of Guangzhou Medical University Ethical Review Board (No. 50 2022).

Rise in Consumerism and its Impact on Sustainable Development

Consumption is the function of disposable income. Consumption contributes a lot to the investment of any country. Consumption in a country depends on the marginal propensity to consume (MPC), Veblen effect, Snob effect, Bandwagon effect, Short sight of the consumer, etc. Keeping this in mind, producers produce those goods and services which can provide satisfaction to the consumers. Advertisement and marketing has become the lifeline of today’s market structure which psychologically attracts the consumer so much that the consumer purchases goods and services without wanting them. Due to this ecological and social problems start in the society. This is where consumerism begins. America’s great economist Professor Thorstein Veblen first spoke on the subject of consumerism which was based on conspicuous consumption. The problem of rising consumerism today is resulting in the reckless use of limited resources bestowed to us by mothernature. Since resources are limited, the excessive use of resources will lead to the exhaustion of non-renewable resources very quickly. Even it will be difficult, if not impossible, to compensate for the loss of renewable resources so fast. Today our greed and irresponsible behavior is the basic reason for all environmental issues and problems be it global warming, deforestation, pollution, or the issue of sustainability. This paper will highlight in detail how rising consumerism has led to many environmental issues and how simple living and high thinking can be the answer to sustainability.

Validation of a method to assess night myopia in a clinical setting

A study was conducted with 115 subjects who regularly drove at night to validate a refraction protocol for detecting refractive visual changes from daytime to nighttime conditions. Objective and subjective refractions were performed in both photopic and mesopic conditions, with a dark adaptation period before the mesopic subjective refraction. The results showed that in mesopic conditions, visual acuity decreased by 0.2 logMAR units on average (p < 0.01), and there was a myopic refractive shift of − 0.36 ± 0.20 D (p < 0.01). Most subjects (92.2%) exhibited a myopic refractive shift of at least 0.12 D. Compensation of refractive shift improved mesopic visual acuity by 0.06 logMAR on average (p < 0.01) and higher refractive shifts showed higher improvement. Night Rx was preferred by 82.1% of subjects with myopic refractive shift. Gender and age did not significantly affect the refractive shift, although myopes showed a higher shift compared to emmetropes (p < 0.01). The refractive shift remained stable over time when the time slot of the day did not change (p < 0.01). Night Rx protocol proved to be a robust and accurate method for identifying drivers with refractive changes when transitioning from photopic to mesopic conditions. The high prevalence and inter-individual variability of Rx shift highlight the need of customized refraction.

Adaptive Illuminance Effects on Retinal Morphology and Refraction: A Comprehensive Study of Night Myopia.

We aimed to study the optical and retinal modifications that occur after adapting to different lighting conditions including photopic, mesopic, scotopic, blue light and red light conditions. Thirty young healthy subjects with a mean age of 23.57 ± 3.45 years were involved in the study (both eyes included). They underwent aberrometry and optical coherence tomography at both the central and peripheral retina with the 3 × 3 mm2 macular cube protocol before starting adaptation to the illuminations (baseline) and after remaining for 5 min under the five different lighting conditions inside a controlled lighting cabinet. Significant myopization (p = 0.002) was observed under scotopic and mesopic lighting conditions, while hypermetropization occurred under the influence of blue LED light. In the central retina, a significant thickening of the inner temporal (p = 0.025) and outer inferior (p = 0.021) areas was observed in the scotopic area, and the thickening increased even more under blue and red light. The mean central thickness decreased significantly under photopic lighting conditions (p = 0.038). There was an increase in the mean volume of the central retinal area with red light and a reduction in the volume under photopic lighting (p = 0.039). In the peripheral retina, no significant thickness changes were observed after adapting to any of the lighting conditions (p > 0.05). Regarding morphological changes, a significant increase in retinal eccentricity (p = 0.045) and the shape factor (p = 0.036) was found. In addition, a significant correlation was found only between the eccentricity and volume of the central retina in scotopic conditions (r = -0.265; p = 0.041), meaning that a higher volume was associated with lower retinal eccentricity. When exposed to different lighting conditions, the retina changes in shape, and ocular refraction is modified to adapt to each condition, revealing the phenomenon of night myopia when transitioning from photopic to scotopic regimes.

Uncorrected near vision acuity and associated factors in a coastal province in southern China: the Fujian eye cross sectional study.

BackgroundNear vision (NV) is essential to visual quality of individuals, and could be affected by different factors and changed gradually with the development of society. An update estimates is needed. Our study aims to investigate the age-trends in and sociodemographic characteristics associated with uncorrected near vision acuity (UNVA) in people ≥50 years in southern China.MethodsA population-based, cross-sectional survey on the eye health status of residents in both inland and coastal areas of Fujian Province, southern China was performed by Eye Institute and Affiliated Xiamen Eye Center of Xiamen University. People aged ≥50 years (10,044 subjects) in Fujian province were recruited according to the cluster sampling design by Fujian eye cross sectional study (FJES) group. The contents of the questionnaire survey included age, gender, education, occupation and other socioeconomic status. UNVA and slit lamp examination were performed for the participants in the field survey. Analysis of variance (ANOVA) was applied to compare the mean among groups of normally distributed parameters of UNVA and the chi-square (χ2) test was used to compare the proportion.ResultsAmong the baseline participants, 8,211 (81.8%) attended follow-up examinations. The sample had a mean age of 64.4 years [standard deviation (SD) =8.9], and 4,836 of the participants were female (58.9%). The average UNVA values for males and females were 0.29±0.18 and 0.28±0.17, respectively (P=0.000). UNVA gradually decreased with age and plateaued between 65 and 80 years old. There were significant differences in the mean values of UNVA associated with different occupations (P=0.000). UNVA was significantly different among people with different education levels (P=0.000). The average UNVA in people in coastal areas was 0.28, while that in people in inland areas was 0.29 (P=0.006). People in urban areas appeared to have better UNVA on average (0.29) than those in rural areas (0.27; P=0.000).ConclusionsAfter age 50, NV was reduced gradually. Age, gender, education, occupation, income and geographical factors may affect the NV performance of adults, which should be taken into account to achieve a good management of vision quality.

Water and sanitation governance between austerity and financialization

Drawing from quantitative and qualitative research, this paper explores the case of COPASA – a mixed-capital regional water and sanitation utility in Brazil facing a context of austerity and privatization. We find that the state government, shrinking in a fiscal crisis, opted to increase extraordinary dividends payouts to raise its revenues. Given the mixed company mode of privatization, the private shareholders endorsed this pattern of governance, motivated by a short sight financial logic. This convergence of different interests led the utility to lower investments, failed investment plans, breaches of contracts with municipalities and making it even harder to universalize the services.

A educação cooperativa como gerador de mudanças sociais: um estudo sobre a 6ª Semana da Educação Financeira na cidade de Itamaraju/BA

O presente artigo discorre sobre os princípios cooperativos constituintes dos sistemas de cooperação, enfatizando os princípios da educação, formação e Informação, e do Interesse pela comunidade. Nesse sentido o problema apontado é como a educação cooperativista pode contribuir na formação e mudança de pensamento das crianças no desenvolvimento da educação financeira? Sendo assim os objetivos apresentados são: analisar a educação cooperativa e suas contribuições na mudança de pensamento das crianças no desenvolvimento da educação financeira, e os objetivos específicos são contextualizar o cooperativismo no Brasil e no mundo; compreender o processo da educação financeira no âmbito escolar e exemplificar a semana da educação financeira proposta pelo Banco Central e executada pelo instituo SICOOB como modelo motivador para o despertar financeiro. A metodologia desenvolvida na pesquisa tem uma abordagem qualitativa e quantitativa, sendo representada pela pesquisa bibliográfica e pesquisa de campo, descrevendo uma breve visão histórica sobre o cooperativismo, a educação e a sociedade.

The Effects of Restricted Sight Distances on Drivers at Simulated Rural Intersections

Short sight distances at rural intersections can result in reduced safety including drivers choosing smaller gaps between oncoming vehicles (Yan &amp; Richards, 2010). Conversely, increased sight distances may result in improved driver confidence, but not safety as seen at rail crossings (Ward &amp; Wilde, 1996). Thus, simply increasing sight distances may not result in linear gains in safety. Establishing appropriate lower and upper-visibility limits at rural intersections will minimize operational costs for clearing and grubbing labor and may reduce serious injury and fatal crashes by promoting safer crossing behavior around rural thru-STOP intersections. This driving simulation study will examine intersection visibility and other intersection design factors that influence driver behavior at rural thru-STOPs. Time to collision, or TTC, is a primary motivating factor on driver decisions to cross intersections. Drivers’ TTC perception is a function of oncoming vehicle speed, distance, and rate of retinal expansion (tau; Hancock &amp; Manser, 1997). We hypothesize TTC factors may interact with confidence in intersection crossing judgments. Specifically, when people must quickly make judgments, their confidence must be estimated after the decision has been made, but if the time pressure is not high and the decision is not immediate, people’s judgments and their confidence in those judgments can both be considered prior to action. This can be problematic because people are normally overconfident in their judgments (Harvey, 1997). The present study comprised a crossing judgment block, and a mainline drive block. The experimental stimuli were validated by engineers with experience in rural intersections, who rated the simulated intersections as “significantly representative” to real-world intersections through an average rating score of 5.25 ( SD = 0.5) on a 7-pt scale. This was done to ensure that the study findings would be more likely to be applicable to world intersections. The goal of the study is to identify whether sight distance and other variables, including speed for the judgment task and vehicle proximity to the intersection for the mainline drive task, impact safety at rural intersections.

Understanding Patient Attitudes Toward Multifocal Intraocular Lenses in Online Medical Forums Through Sentiment Analysis.

Multifocal intraocular lens implants (IOLs) are a premium option for cataract surgery which patients may purchase to achieve improved spectacle-independence for near vision but may have trade-offs with visual quality. We demonstrate the use of sentiment analysis to evaluate multifocal lenses discussed on MedHelp, a leading online health forum. A search for "multifocal IOL" was performed on MedHelp.org on November 1, 2016, yielding relevant patient posts. Sentiment analysis was performed using IBM's Watson, which extracted 30,066 unique keywords and their associated sentiment scores from 7495 posts written by 1474 unique patient users. Keywords associated with monovision, monofocal, and toric lenses had positive mean sentiment, significantly higher than for keywords associated with multifocals, which had negative mean sentiment (p < 0.001, ANOVA). Many keywords represented complaints and were associated with negative sentiment, including glare, halo, and ghosting. Sentiment analysis can provide insights into patient perspectives towards multifocal lenses by interpreting online patient posts.

Evaluation of corneal biomechanical properties modification following intrastromal correction of presbyopia using femtosecond laser

Objective To investigate the changes of corneal biomechanics of intrastromal correction (INTRACOR) femtosecond technique to treat presbyopia. Methods A prospective, clinical self-control clinical trial was designed.Twenty-four presbyopic patients with emmetropia or mild hyperopia were enrolled in this study.The INTRACOR procedure was performed using the Technolas femtosecond laser in the nondominant eye.Uncorrected distance visual acuity (UCDVA), uncorrected near visual acuity (UCNVA) and spherical equivalent (SE) were recorded in preoperation and postoperative 12 months, and the quality of life of postoperative patients was evaluated.The corneal deformation parameters including highest concavity deformation amplitude (HC-DA), highest concavity peak distance (HC-PD), highest concavity radius (HC-R), non-contact intraocular pressure and the central corneal thickness (CCT) were measured using the Corvis ST visualization biomechanical analyzer in preoperation and postoperative 1 month, 3, 6 and 12 months, respectively.This study followed the Declaration of Helsinki.Written informed consent was obtained from each subject prior to entering study cohort.This study protocol was approved by Ethic Committee of Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine (No.SDZYYDXYKYYLL2011.06). Results Compared with preoperation, UCNVA of all 24 (100%) eyes was improved at 12 months postoperatively with minimal or no change in UCDVA.The mean spherical equivalent was (+ 0.35 ± 0.29)D and (-0.37 ± 0.29)D before and 12 months after operation, with a significant difference beteeen them (t=-7.39, P 0.05). Compared with preoperation, the postoperative 1 month, 3, 6, 12 months HC-R values were significantly declined, HC-DA values were significantly increased, with significant differences between them (all at P 0.05). Corneal aspherical index (Q Value) was -0.28±0.10 at 12 months postoperatively, which was increased compared with the preoperation, and the maximum value added value (diff-K) of the central corneal curvature was (2.55±0.81)D. Conclusions INTRACOR treatment of presbyopia can effectively improve near vision, increase postoperative corneal biomechanical maximum HC-R and HC-DA, negatively increase the corneal central curvature increased aspheric index, which suggests that corneal biomechanics of central cornea is weakened after intrastromal femtosecond presbyopic treatment, and the hyperprolate mutifocal corneal shape is formed under normal intraocular pressure. Key words: Presbyopia; Femtosecond laser; Intrastromal correction; Perspective study; Corneal biomechanics; Corneal aspherical index

Management of Simple Myopia with Anantadi Ghrita: A Case Report

Ayurveda can serve better in many disease conditions, where conventional system face several limitations. Refractive errors are among such conditions, where effective management is becoming a challenge. Myopia or short sight, is that form of refractive error wherein parallel rays of light come to focus in front of sentient layer of the retina when the eye is at rest. Around 60% cases of blurred vision are due to simple myopia and this may present from simple eye strain to blurring of vision. The contemporary medicine advices optical correction and lasik surgery for managing this condition; whereas Ayurveda provides better care and prevent complications in initial stages. As many of the individuals may not prefer surgery; a great emphasise on the alternative measures for satisfactory management is the need of the hour. In this paper, a case of simple myopia managed with Ayurvedic protocol has been presented.

การสำรวจอาการสายตาสั้นตอนกลางคืนในประเทศไทย

การสำรวจอาการสายตาสั้นตอนกลางคืนในประเทศไทย

Stereopsis function of presbyopia effected by correcting of monovision contact lens

Objective This study was to study the effect of monovision contact lens (MV-CL) on distant and near vision, distant and near stereopsis, and to identify the effect of degree of monovision on vision function. Methods A prospective case observational study was designed.The clinical data of sixty-eight eyes of 47 cases were collected from November 2010 to August 2014 in Henan Provincial Corps Hospital, Chinese People's Armed Police Forces.Sixty-eight eyes of 47 cases wore contact lenses to improve near vision, in which the other eye of 21 cases with hyperopia wearing contact lenses to improve distant vision.Besides, far and near stereopsis were measured before and two weeks after wearing lenses respectively; and scotopia were measrued with lenses and in naked eyes respectively.Compared the changes of vision and stereopsis in patients before and after the MV-CL, and conducted the patient satisfaction survey. Results There were 89% (42/47 cases) and 6% (3/47 cases) of the patients whose naked far and near vision was 0.8/0.33(J4) at 2 weeks after MV-CL and before MV-CL, respectively.There were no statistical significance about change of near stereopsis with Titmus stereopicture and the Yan's near random-dot stereogram (χ2=1.30, 0.56; both at P>0.05). There were no statistical significance about change with apparent machine random dot stereogram iterative crossed parallax and uncrossed disparity (χ2=0.16, 0.11; both at P>0.05). The far distance fusion range and far stereopsis were not significantly different between before and after MV-CL (χ2=0.22, 0.16; both at P>0.05). Titmus stereopicture tests showed that there was a decrease in the number of people who had foveal stereopsis, while an increase was found in people who had macular stereopsis after MV-CL, but the difference had no statistical significance (χ2=2.28, P>0.05). Conclusions Near vision can be obviously increased and presbytism can be relieved by MV-CL.Stereopsis of some patients are decreased after MV-CL, but this can be accepted by the patients and there is no obvious decrease in far range of fusion. Key words: Monovision; Presbyopia; Contact lens; Stereopsis

Long-term clinical effect of aspheric multifocal intraocular lens implantation for developmental cataracts in childhood

Objective To observe the long-term visual quality and clinical effect of aspheric diffractive multifocal intraocular lens (IOL) implantation for congenital and developmental cataracts in childhood. Methods A retrospective cohort study on multifocal IOL implantation for congenital and developmental cataracts in childhood (aged 8 to 14 years) was performed in the First Affiliated Hospital of Zhengzhou University from August 2013 to January 2015.The clinical data of 67 eyes from 46 congenital cataract patients who received phacoemulsification with IOL implantation were collected.The AMO (ZMB00) IOL was implanted in 34 eyes of 24 patients in the multifocal IOL group, and Bausch & Lomb (MI60) IOL was implanted in 33 eyes of 22 patients in the monofocal IOL group.The distance, intermediate and near vision acuity were analyzed in 3, 6 and 12 months after surgery, including uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA). The wavefront aberrations, modulation transfer functions (MTF) and stereopsis were obtained with iTrace Analysis System, Optec-6500 Visual Functional Analyzer and Titmus Stereo Test Chart, respectively in 12 months after surgery.The near additional degree, removing glasses rate and myopic shift were compared between the two groups in postoperative 12 months. Results The intermediate and near UCVA in the multifocal IOL group were obviously better than those in the monofocal IOL group 3, 6 and 12 months after surgery (intermediate: Z=-3.74, -4.36, -3.66; all at P=0.00.near: Z=-2.67, -2.50, -2.33; all at P 0.05). The MTFs under the 5.0 mm optical zone and 5, 10, 15, 20, 25, 30 c/d in the multifocal IOL group were insignificantly lower than those in the monofocal IOL group (all at P>0.05). In addition, the near stereopsis, near additional degree and myopic shift (ΔD) were reduced in the multifocal IOL group compared with monofocal IOL group (both at P 0.05). The myopic shifting rates were 16.7% and 83.3% in the multifocal IOL group and monofocal IOL group, with a significant difference between the two groups (χ2=15.02, P=0.00). Conclusions The aspheric multifical IOL implantation can achieve good and stable distance, intermediate and near visual acuities, provide better near stereopsis, reduce postoperative dependence on spectacles and decrease the incidence of myopic shift in child cataract patients. Key words: Congenital cataract; Intraocular lens; Prosthesis implantation; Aspheric; Multifocal; Wavefront aberration; Modulation transfer function; Childhood

A Dynamic-Logical Characterization of Solutions to Sight-limited Extensive Games

An unrealistic assumption in classical extensive game theory is that the complete game tree is fully perceivable by all players. To weaken this assumption, a class of games (called games with short sight) was proposed in literature, modelling the game scenarios where players have only limited foresight of the game tree due to bounded resources and limited computational ability. As a consequence, the notions of equilibria in classical game theory were refined to fit games with short sight. A crucial issue that thus arises is to determine whether a strategy profile is a solution for a game. To study this issue and address the underlying idea and theory on players’ decisions in such games, we adopt a logical way. Specifically, we develop a logic through which features of these games are demonstrated. More importantly, it enables us to characterize the solutions of these games via formulas of this logic. This work not only provides an insight into a more realistic model in game theory, but also enriches the possible applications of logic.

Comparison of implantation of multifocal intraocular lens with different additional diopter

Objective To compare the visual quality after implantation of multifocal intraocular lenses(IOLs)with different additional diopter or their combination in both eyes. Methods One hundred and eighty eyes of 90 patients with cataract that underwent phacoemulsification and implantation of a multifocal IOL were divided into 3 groups, each group had 60 eyes of 30 cases. The + 2.5 D group received IOL implantation of + 2.5 D addition; the+ 3.0 D group received IOL implantation of + 3.0 D addition; the combined group of binocular received IOL implantation both + 2.5 D addition in one eye and + 3.0D addition in other eye. The visual acuities of 30 cm, 50 cm and 5m were observed 6 months after surgery. Quality of vision, patient satisfaction and spectacle independence were evaluated with the National Eye Institute Refractive Error Quality of Life Instrument-42 questionnaire. Results The difference in uncorrected distant vision was not significant among 3 groups 6 months after surgery.The uncorrected near vision in+ 3.0 D group and the combined group were better than that in + 2.5 D group(P=0.003, 0.016). In + 2.5 D group and the combined group uncorrected intermediate vision were better than that in+ 3.0 D group(P=0.000, 0.002). The uncorrected vision at 30 cm, 60 cm and 5 m distances in the combined group were good after surgery.In the combined group, the expectation(P=0.017, 0.002) and activity limitation(P=0.006, 0.019)were obviously better than those in other two groups.The + 2.5D group of incidence of glare was less than that of other two groups(P=0.004, 0.009). The differences in other survey items of the three groups were not statistically significant. Conclusion The bilateral implantation of the same multifocal IOL can improve the vision of near and intermediate distances, the combination of these IOLs in both eyes can increase the range of spectacle independence without compromising the contrast sensitivity and quality of vision. Key words: Lens, intraocular, multifocal; Cataract; Visual acuity, distance, intermediate, near

Refractive Changes Induced by Spherical Aberration in Laser Correction Procedures: An Adaptive Optics Study.

To study the effect on vision of induced negative and positive spherical aberration within the range of laser vision correction procedures. In 10 eyes (mean age: 35.8 years) under cyclopegic conditions, spherical aberration values from -0.75 to +0.75 µm in 0.25-µm steps were induced by an adaptive optics system. Astigmatism and spherical refraction were corrected, whereas the other natural aberrations remained untouched. Visual acuity, depth of focus defined as the interval of vision for which the target was still perceived acceptable, contrast sensitivity, and change in spherical refraction associated with the variation in pupil diameter from 6 to 2.5 mm were measured. A refractive change of 1.60 D/µm of induced spherical aberration was obtained. Emmetropic eyes became myopic when positive spherical aberration was induced and hyperopic when negative spherical aberration was induced (R2 = 81%). There were weak correlations between spherical aberration and visual acuity or depth of focus (R2 = 2% and 3%, respectively). Contrast sensitivity worsened with the increment of spherical aberration (R2 = 59%). When pupil size decreased, emmetropic eyes became hyperopic when preexisting spherical aberration was positive and myopic when spherical aberration was negative, with an average refractive change of 0.60 D/µm of spherical aberration (R2 = 54%). An inverse linear correlation exists between the refractive state of the eye and spherical aberration induced within the range of laser vision correction. Small values of spherical aberration do not worsen visual acuity or depth of focus, but positive spherical aberration may induce night myopia. In addition, the changes in spherical refraction when the pupil constricts may worsen near vision when positive spherical aberration is induced or improve it when spherical aberration is negative. [J Refract Surg. 2017;33(7):470-474.].

Comparison on the efficacy between the multifocal and monofocal aspheric toric intraocular lens in cataract patients

Objective To compare the clinical efficacy between the multifocal and monofocal aspheric toric intraocular lens in cataract patients. Methods Seventy-two eyes of 56 patients with age-related cataract underwent phacoemulsification were randomly divided into 2 groups. In group A, the aspheric multifocal toric intraocular lens were implanted in 37 eyes of 29 patients. In group B, the aspheric monofocal toric intraocular lens were implanted in 35 eyes of 27 patients. After surgery, the visual acuity, postoperative residual corneal astigmatism, the IOL axis rotational stability, higher-order aberrations and contrast sensitivity were observed and statistically analyzed. Results At 3 months after surgery, the differences in uncorrected near visual acuities (log MAR) were statistically significant between two groups (t=8.569, P=0.003). There was no significant difference in the uncorrected distance, corrected distance or near visual acuity (log MAR) between two groups (t=1.578、1.325、1.098, P= 0.236、0.281、0.217). There was no significant difference in postoperative residual corneal astigmatism between two groups (t=1.775, P=0.135). There was no significant difference in the axis rotation between two groups (t=2.165, P=0.117). There was no significant difference in the general higher-order aberration, 3-order aberration, 4-order aberration or 5-order aberration root mean square value between two groups (t=1.567, 1.256, 1.457, 1.298, P=0.167, 0.158, 0.136, 0.237). There was no significant differrence at any spatial frequenciy of contrast sensitivity function between two groups (t=1.256, 2.359, 1.238, 2.258, 2.156, 1.982, 2.032, 2.987, P= 0.982, 0.758, 0.875, 0.702, 0.112, 0.189, 0.238, 0.356). Conclusion Phacoemulsification combined with aspheric multifocal toric intraocular lens implantation is an effective method for the correction of preexisting corneal astigmatism in cataract patient. The better uncorrected distance and near visual acuities are obtained for cataract patients. The surgery improves spectacles independence for distance vision and spectacles independence for near vision, with a high patient satisfaction. Key words: Cataract, age-related; Lens, intraocular, multifocal, monofocal, astigmatism-correcting, aspherical

Visual outcome of multifocal intraocular lenses implantation for unilateral cataract

Objective To evaluate the visual outcomes of multifocal intraocular lens (IOL) implantation for unilateral cataract and compare with binocular cataract multifocal IOL. Methods Age related cataract patients with age 40-70 years were collected and divided into two groups. Monocular group included 30 eyes of 30 patients with monocular cataract, and the other eyes were no significant cataract or early cataract needn′t surgery. Bilateral group included 64 eyes of 32 patients with binocular cataract. Patients were implanted with multifocal IOLs unilaterally or bilaterally.Three months postoperatively, monocular and binocular uncorrected distance, intermediate and near visual acuity, contrast sensitivity, and near stereoacuity, the rate of spectacle glass independence and patient′s satisfaction were examined and assessed. Results The mean binocular uncorrected distance, intermediate, and near vision (logMAR) in the unilateral group were (0.10±0.14), (0.29±0.16), (0.28±0.24) and in the bilateral group were (0.09±0.19), (0.24±0.13), (0.26±0.17). The difference was not significant between the two groups (t=0.32、0.54、0.78, P=0.75、0.59、0.44). Near stereoacuity was slightly worse in the unilateral group than in the bilateral group(χ2=5.16, P=0.02). The rate of spectacle glass independence was 62.50% in the unilateral group and 71.88% in the bilateral group. There was no significant difference among the two groups (χ2=0.52, P=0.47). The differernce in patient satisfaction of the two groups was not statistically significant(χ2=0.52, P=0.53). Conclusion Unilateral implantation of multifocal intraocular lens may increase the rate of spectacle glass independence and improve patient satisfaction. The treatment of implantation of multifocal intraocular lens for monocular cataract is worthy of recommendation. Key words: Cataract, unilateral; Lens, intraocular, multifocal; Visual outcome

Prevalence and causes of visual impairment among teachers in Onitsha, Nigeria

Objectives: The aim of this article is to determine the prevalence and causes of visual impairment among teachers in Onitsha, Nigeria. Materials and Methods: Teachers were selected by multistage random sampling from 10 secondary schools in Onitsha. A pretested, self-administered questionnaire was used to elicit information on each participant’s sociodemographic characteristics and ocular health. Ocular examination included distance and near visual acuity tests, external eye examination, refraction, and funduscopy. Results: Three hundred forty teachers consisting 63 males (18.5%) and 277 females (81.5%) were studied. The age range was 24 to 60 years; mean − 45.2 ± 7.4 years. The prevalence of visual impairment was 11.2%. None of the teachers were blind. The most common causes of visual impairment were uncorrected refractive error (55.2%), cataract (15.8%), diabetic retinopathy (7.9%), and hypertensive retinopathy (7.9%). Near vision impairment from presbyopia occurred in 79.1%. Conclusion: Presbyopia and refractive errors were the common causes of near and distance visual impairment, respectively, in the teachers. Annual eye examination of teachers will help detect early and treat the ocular problems that may militate against effective performance. The ocular health needs of teachers should, thus, be well accommodated in the school eye health program to ensure optimal productivity of teachers in the education sector.