Near Vision Research Articles

Pattern of Change in Accommodation and its Correlation with Mydriasis in Young Emmetropes After Instillation of Tropicamide Phenylephrine Eye Drops

Cycloplegics relax accommodation by blocking the action of ciliary muscles. The mydriasis obtained with these drugs is expected to be related to the degree of cycloplegia. This study evaluates the change in accommodation in young emmetropes and its correlation with mydriasis post instillation of tropicamide phenylephrine eye drops. A prospective descriptive study. Young adults of age group 18-22 years with uncorrected visual acuity of 6/6, near vision N6 and no asthenopic symptoms were included in the study. Age of the subject, NPA (near point of accommodation), NPC (near point of convergence), AA (accomodation amplitude), objective refraction with Autorefractometer, pupillary size and near vision (NV) were noted. The study group included 25 cases; mean age of 20.54 years (SD 1.046years). The amount of accommodation relaxed by drug ranged from 2.75D to 4.50 D. NPA, NPC, AA were inversely proportional to accommodation relaxed (p=0.00). The rate of change of pupillary dilatation and cycloplegia differed. The cycloplegic effect had a positive correlation with the increase in the visual angle; but was independent of the mydriatic effect.

Preference at First Sight

We consider decision-making and game scenarios in which an agent is limited by his/her computational ability to foresee all the available moves towards the future - that is, we study scenarios with short sight. We focus on how short sight affects the logical properties of decision making in multi-agent settings. We start with single-agent sequential decision making (SSDM) processes, modeling them by a new structure of "preference-sight trees". Using this model, we first explore the relation between a new natural solution concept of Sight-Compatible Backward Induction (SCBI) and the histories produced by classical Backward Induction (BI). In particular, we find necessary and sufficient conditions for the two analyses to be equivalent. Next, we study whether larger sight always contributes to better outcomes. Then we develop a simple logical special-purpose language to formally express some key properties of our preference-sight models. Lastly, we show how short-sight SSDM scenarios call for substantial enrichments of existing fixed-point logics that have been developed for the classical BI solution concept. We also discuss changes in earlier modal logics expressing "surface reasoning" about best actions in the presence of short sight. Our analysis may point the way to logical and computational analysis of more realistic game models.

Night myopia is reduced in binocular vision.

Night myopia, which is a shift in refraction with light level, has been widely studied but still lacks a complete understanding. We used a new infrared open-view binocular Hartmann-Shack wave front sensor to quantify night myopia under monocular and natural binocular viewing conditions. Both eyes' accommodative response, aberrations, pupil diameter, and convergence were simultaneously measured at light levels ranging from photopic to scotopic conditions to total darkness. For monocular vision, reducing the stimulus luminance resulted in a progression of the accommodative state that tends toward the subject's dark focus or tonic accommodation and a change in convergence following the induced accommodative error. Most subjects presented a myopic shift of accommodation that was mitigated in binocular vision. The impact of spherical aberration on the focus shift was relatively small. Our results in monocular conditions support the hypothesis that night myopia has an accommodative origin as the eye progressively changes its accommodation state with decreasing luminance toward its resting state in total darkness. On the other hand, binocularity restrains night myopia, possibly by using fusional convergence as an additional accommodative cue, thus reducing the potential impact of night myopia on vision at low light levels.

Glaucoma: the patient's perspective.

#### Clinical Question What are the concerns of patients with glaucoma and how can they be addressed in general practice? Glaucoma is the leading cause of irreversible blindness worldwide, affecting more than 70 million people, with half unaware they are affected.1–3 As glaucoma cannot be cured, patients require lifelong monitoring and treatment. The aim of this article is to provide an update on glaucoma from the patient’s perspective by addressing some commonly raised questions. Glaucoma is an optic neuropathy characterised by loss of retinal ganglion cells and accompanying loss of visual field (Figure 1). Although raised intraocular pressure (IOP) is the major risk factor, some patients develop glaucoma with normal IOP (≤21 mmHg), whereas others have high IOP but do not have glaucoma (ocular hypertension). As glaucoma can be asymptomatic until later stages, for most patients diagnosis follows the unexpected discovery of an abnormality on routine testing at a high-street optometrist. It is therefore important to encourage regular eye examinations.3 Figure 1. Optic disc photograph and visual field showing advanced glaucoma in the left eye. Glaucoma can be divided into open or closed angle, the angle referring to the opening between the iris and cornea, the location of the trabecular meshwork. Both open and angle closure glaucoma can be divided into primary and secondary subtypes. Primary open angle glaucoma (POAG) is the most common type in the UK, affecting 2% of those aged >40 and 10% of those >75 years. Risk factors include age, short sight, family history, African–Caribbean ancestry, and diabetes. Glaucoma …

Comparison of visual quality after the implantation of different types of intraocular lens

Objective To compare the efficacy of different types of intraocular lens (IOL) implantation for age-related cataract. Methods A retrospective case series. Clinical data of 148 eyes of 162 cases of age-related cataract, were collected from April to December in 2014 at our hospital and all subjects were divided into three groups: simple cataract surgery combined with the traditional spherical IOL implantation in 44 eyes, zero spherical aberration AO IOL implantation in 56 eyes and negative spherical aberration ZCB IOL implantation in 48 eyes. The differences in patients age, preoperative uncorrected distance visual acuity and axial length among three groups were not statistically significant (P>0.05). The corneal astigmatism of all patients were less than 0.75 D. Uncorrected distance visual acuity (UCVA), best corrected distance visual acuity (BCVA), uncorrected near visual acuity (UNVA) and best corrected near vision (BCNA) were assessed preoperatively, 1 week, 1 month and 3 months after the surgery. And the ocular spherical aberration of the patients in 3 groups were assessed 3 months after the surgery. The total ocular spherical aberration of all subjects were measured by using the Ray tracing methed with pupil diameters of 4.0 mm. Results After three months, there were not statistically significant differences in UCVA, BCVA, UNVA and BCNA among three groups. After three months there was statistically significant difference among groups in total ocular spherical aberration. According to the data of corneal spherical aberration, the total ocular spherical aberration of patients in each group was divided into 3 grades. It is founded that the total ocular spherical aberration had no statistically significant defferences among groups when the corneal spherical aberration grade was less than 0.15 μm or greater than 0.45 μm. However, there was statistically significant difference when corneal spherical aberration grade was from 0.15 m to 0.45 μm. Conclusion Our earlier observation shows that negative spherical aberration IOL implantation is superior to traditional spherical IOL and aspheric IOL. Key words: Lens, intraocular, various types; Spherical aberration; Visual quality; Comparation

Visual acuity and magnification devices in dentistry.

This review discusses visual acuity in dentistry and the influence of optical aids. Studies based on objective visual tests at a dental working distance were included. These studies show dramatic individual variation independent of the dentists’ age. The limitations due to presbyopia begin at an age of 40 years. Dental professionals should have their near vision tested regularly. Visual deficiencies can be compensated with magnification aids. It is important to differentiate between Galilean and Keplerian loupes. The lightweight Galilean loupes allow an almost straight posture and offer improved ergonomics. Younger dentists profit more from the ergonomic aspects, while dentists over the age of 40 can compensate their age-related visual deficiencies when using this type of loupe. Keplerian loupes, with their superior optical construction, improve the visual performance for dentists of all age groups. The optical advantages come at the cost of ergonomic constraints due to the weight of these loupes. The microscope is highly superior visually and ergonomically, and it is indispensable for the visual control of endodontic treatments.

Effectiveness of Bates Therapy on Visual Problems Among Elderly People

The eye is the window of the human body through which it feels its way and enjoys the beauty of the world, but as age rises elderly people develop visual problems by showing the symptoms like blurred vision, visual defect, fore sight and short sight, etc, which blocks the beauty of eye sight.

A logical characterization of extensive games with short sight

The notion of short sight, introduced by Grossi and Turrini, weakens the unrealistic assumption in traditional extensive games that every player is able to perceive the entire game structure. In this paper, we propose a more general model for extensive games with short sight. For reasoning about extensive games with short sight, we propose a new logic language and then present an axiomatization for this logic. We prove the soundness and completeness of the axiomatization. In addition, we show that the logic can formally characterize the solution concepts and Pearce's lemma in games with short sight.

The relationship between the different refractive states and daily activity after cataract surgery in highly myopic eyes

Objective To evaluate postoperative daily visual activity of highly myopes after cataract surgery. Methods Data of studied 120 eyes of 60 cases with cataract surgery and high myopia who underwent cataract surgery in our hospital were retrospectively analyzed. The patients were divided into three groups based on postoperative diopters: group A (-1.0~-2.0D), group B (-2.25~-3.0D) and group C (-3.25~-4.0D). The questionnaires of Activities of Daily Vision Scale (ADVS) were collected to assess the vision three months after the cataract surgery. Results The numbers of patients who satisfied with the surgery were 11 in group A, 8 in group B, and 13 in group C, and the difference were not statistically significant among three groups (χ2=4.23, P=0.38). No statistically significant difference was observed among three groups in postoperative life self-care ability, mental state and interest survey (χ2=4.23, P=0.38). Depending on the postoperative visual qualities, there were no statistically significant differences in night vision (χ2=3.39, P=0.415) and the vision for watching TV among three groups (χ2=4.20, P=0.38). But for reading and writing capabilities, the vision of patients in group A was poorer than that of patients in group B and C (χ2=10.62, P=0.005; χ2=16.25, P=0.0015; χ2=4.64, P=0.2). Patients in group C had better fine resolution than those in group A and B (χ2=5.26, P=0.072; χ2=19.54, P<0.001; χ2=9.09, P=0.011). There was statistically significant difference in wearing glasses among three groups (χ2=29.67, P<0.001). For distant vision, the wearing rate were 40% in group A, 95% in group B and 100% in group C. For near vision, the wearing rate were 75% in group A, 40% in group B and 30% in group C. Conclusion Cataract surgery in highly myopic eyes can improve qualities of vision and life. For patients who are not used to wearing glasses and working at near distant, it's appropriated to reserve a minor degree of myopia. Conversely, for patients who require to work at near distant and can receive wearing moderate or low hyperopia mirror, higher degree of myopia can be reserved. Key words: Myopia, high; Cataract; Refraction, ocular; Activities of daily vision scale

Comparison of implanting two kinds of multifocal intraocular lens with different near add

Objective To compare the visual quality of implanting two kinds of multifocal intraocular lens (MIOL) with different near add. Methods This prospective, comparative, nonrandomized single-blind observational study comprised of 30 eyes of 25 patients that underwent phacoemulsification and implantation of multifocal IOL: SN6AD2 (13 cases, 16 eyes) (+ 2.5 D group) and SN6AD1 (12 cases, 14 eyes) (+ 3.0 D group). Three months after the surgery, the uncorrected visual acuity and monocular near (33 cm and 40 cm), intermediate (50 cm, 60 cm, and 70 cm), and far distance (5 m) best corrected visual acuity were evaluated. Double focal curves were measured, and questionnaires of patients after phacoemulsification were collected. All of the parameters were evaluated at the 4-6mm pupil sizes. Results There was no statistically significant differences at far and near distance visual acuity were found between the two groups(P>0.05). The + 2.5 D group obtained better performances at all intermediate distances (50 cm, 60 cm and 70 cm; P<0.05). Whereas the near visual acuity was better in the + 3.0 D group (33cm; P<0.05). Both the two groups had double summit in the double focus curve. The summit of + 2.5 D group was at 0.0 D~2 D. The summit of + 3.0 D group was at 0.0 D~2.5 D. There was a high visual acuity level at 0.5 D~2.0 D in + 2.5 D group. The questionnaire showed that it was satisfactory in near and far distance vision in both the two groups. But + 2.5 D group had better result in vision than + 3.0 D group in middle range vision (P<0.05). No interference such as dark vision dropping, flare or halo was observed. Conclusion Both of the two IOL models showed good results in distance vision. The + 2.5 D MIOL seems to provide better intermediate vision than the + 3.0 D MIOL. For near vision(33cm), the + 3.0 D MIOL performs better result than the + 2.5 D MIOL. Key words: Lens, intraocular, multifocal; Cataract; Intermediate visual acuity; Double focal curves

Recent progress of weightlessness impact on the eye

The impact of weightlessness on the eye becomes more and more important with the increase of human space exploration. There is significant elevation in cephalad fluid and ophthalmic vein when individuals are in the state of weightlessness. In this paper, we review adverse effects in weightlessness station, including: retina damage (disc edema, choroidal folds, cotton wool spots, nerve fiber layer thickening), visual function decrease (decreased near vision, decreased ability of acquire and fixate on the target), and intraocular pressure increase.

Myopia and daylight in schools: a neglected aspect of public health?

A century ago, it was widely believed that high levels of daylight in classrooms could prevent myopia, and as such, education departments built schools with large windows to try to stop children becoming short-sighted. This practice continued until the 1960s, from which time myopia was believed to be an inherited condition. In the years that followed, less emphasis was placed on preventing myopia. It has since become more common, reaching epidemic levels in east Asia. Recent research strongly suggests that the amount of light children get as they grow determines whether they will develop short sight; however, evidence that daylight in classrooms prevents myopia is lacking. Given the rapid increase in prevalence among school children worldwide, this should be investigated.

Comparison of two different surgical treatments of presbyopia for hyperopic patients over 55 years old: Presbylasik (Supracor) and Prelex (presbyopic lens exchange)

AbstractPurpose To compare the efficiency and safety of two surgical treatments of presbyopia, Presbylasik and presbyopic lens exchange (Prelex), and to assess patients’ satisfaction with both procedures.Methods It is a retrospective monocentric clinical trial between 06/2011 and 03/2014 comparing implantation of diffractive multifocal intraocular lenses (Finevision Micro F, PhysIOL) and Supracor (Technolas Perfect Vision, GmbH).Results Forty‐two eyes of 21 patients were treated by 3 physicians, with a mean follow‐up of 3 months. Twenty‐six eyes of 13 hyperopic/presbyopic patients were included for Supracor and 16 eyes of 8 patients for Prelex. Patients were aged over 55. Mean uncorrected binocular distance (DV) and near vision (NV) visual acuity (VA) in the Supracor group were respectively 0,03 (‐0,2 – 0,1) LogMar and 0,23 (0,06 – 0,36) one week post‐operatively and 0,031 (‐0,2 – 0,1) and 0,166 (0,06 – 0,36) 3 months post‐operatively. In the Prelex group, the mean uncorrected one week binocular VA was 0,025 (0 – 0,1) for DV and 0,165 (0,06 – 0,18) for NV and the three months VA was 0 (‐0,1 – 0,1) and 0,105 (0,06 – 0,18) for DV and NV. All Prelex patients were spectacle‐free at all distances, whereas 4 Supracor patients required spectacles for NV post‐operatively. Patients’ satisfaction was high in both groups. Patients reported more halos in the Prelex group (75%). One eye required intraocular lens exchange and 4 eyes (16,7%) required a new corneal procedure in the Supracor group.Conclusion Both surgeries have effective and safe modalities in hyperopic and presbyopic patients. Prelex procedure seems to be more appropriate for patients over 55 yo.

Preference dynamics in games with short sight

We study preference dynamics in extensive games with short sight. To do so, first, we represent the priority structure as a partial-ordered priority graph instead of a linear-ordered sequence. By introducing priority graph to extensive games, we obtain the definition of prioritized games and graph-induced preference. Second, in order to deal with the situation in which a player only has incomplete information about the relevant properties and she has to decide her preference, we introduce beliefs and define belief-based preference. We propose an algorithm for such games and further explore its relationship with heuristic search algorithm in AI. Third, we investigate preference dynamics in games with regard to the changes in three kinds of triggers: priority graph, belief, and sight. We show how these changes lead to changes in preference.

TRAFFIC CONTROL FOR MAINTENANCE ON HIGH-SPEED HIGHWAYS

Observations were made at lane closures on Interstate highways to compare effectiveness of yellow and orange signs. One sign scheme was used throughout the study. Driver obedience improved when new signs of either color were used; this finding implies that signs should always be maintained in good condition. Orange signs were slightly more effective than yellow signs in reducing traffic conflicts and merges near the traffic cones. Results of the study tend to support the adoption of orange as the standard color for signing construction and maintenance sites. However, differences between the two colors were rather small. Driver preference polls supported the orange signs more strongly. A degree of driver insensitivity toward signing was shown. In general, variables such as short sight distances, high volumes, poor condition of signs, and driver insensitivity produced unsafe situations at lane closures. However, the scope of the study did not permit observations at sufficient sites or at sufficient times to serve as a definitive exploration of such variables as weather, terrain, vertical and horizontal alignment, or level of service.

A light adjustable lens with injectable optics.

The light adjustable lens (LAL) is an innovative intraocular lens optic composed of partially polymerized macromers with an appropriately bonded photosensitizer. The injectable technology and multifocality associated with the LAL can produce precise refractive correction and, it is hoped, the type of accommodative range that is taken for granted during youth. Combining these technologies with a lens material that behaves like the crystalline lens of 25-year-old could precisely return near and distance vision to older adults.

Experimental study on safety of compound Tiaoshi-plaster to prevent and cure the younth's short sight

Objective To observe the safety of the compound Tiaoshi-plaster's use to skin,providing the scientific foundation for its use to the treatment for the younth's short sight.Methods Experiment 1,acute toxicity test for skin of rabbits:rabbits were randomly divided into two groups:a integrated skin group and a damaged skin group,in addition,every group further divide into high and low dosage group and vehicle control group,totally 5 groups.All above groups received the plaster or vehicle for 24 hours,then take away the drug,and after lh,24 h,48 h,72 h since the 7th day,observe each group's reaction separately everyday,to see whether there is a acute toxicity reaction or not.Experiment 2,self control group,use onerabbit's left and right sides' skin to observe stimulus toxicity via skin:divide the rabbits into a integrated skin group and a damaged skin group,in addition,every group further divide into high,low dosage group and vehicle control group,totally 6 groups.Observe the reaction after multiple doses,after 7 days' successive doses,take the drug-used tissues to do pathological examination.Experiment 3,cavy's skin irritation test:cavies were divide into vehicle group,plaster group,positive group,totally 3 groups,at the 6h,7th day,14th day,take off right side's skin of every group to do the provocative test respectively.On the 28th day,take off the left side's skin to do the provocative test.To see if the skin or the whole body is allergic to the plaster.Results In experiment 1,toxic response could not be found in any group; In experiment 2,rabbits in the integrated skin group didn't show redness or edema,rabbits in the damaged skin group all had redness and edema,but the differences were not statistically significant,compared with the corresponding time of vehicle group (P＞0.05).Such skin damage was not caused by plaster usage but inflammatory reaction of skin damage.In experiment 3,the vehicle group and the study group didn't show any abnormal anaphylactic reaction.Conclusion The compound Tiaoshiplaster is safe to skin. Key words: Compound Tiaoshi-plaster; Younth's short sight; Acute toxicity test for skin; Provocative test for skin; Anaphylactic test for skin

Utility and Results of Short Sight Echocardiography in Pre-test Evaluation of Candidates for Sports/Professional Training

Utility and Results of Short Sight Echocardiography in Pre-test Evaluation of Candidates for Sports/Professional Training

A novel concept of accommodation:Human eyes optical system based on hyperfocal distance-micro zoom

Based on a concept of the hyperfocal distance from photographic lens,this study proposes that emmetropia presents far-hyperfocal distance,near-hyperfocal distance and accommodative hyperfocal distance.When emmetropic presbyopias completely lose the ability of accommodation,its farthest blur point is not beyond 1.5 m,even not being at infinity,and the phenomenon of dark focus both completely match with the definition of hyperfocal distance.On the other hand,after cycloplegic mydriatics in emmetropia,it could be found in the region of depth-of-field that there is no change in the back depth of field (clearness in far vision),but change was found in the front depth of field (blur in near vision).It conforms well to the definition of the hyperfocal distance,demonstrating that human eyes belong to the hyperfocal distance optical system.Furthermore,it is reported that the emmetropic presbyopias rarely matched the spectacles higher than +2.50 D in their whole life;therefore,it can be inferred that their accommodative amplitude in youth is equal to this corrected value.This value accounts for about 4％ of the total refractive power in human eyes,so it is suggested that human eye is a micro zoom optical system.Based on the objective existence of hyperfocal distance,the author proposes that human eye is an integrated accommodative mechanism.It includes three components:the accommodative mechanism of near vision,the measuring and controlling mechanism of near vision,and the general control of near vision.This paper discusses the accommodative mechanism of near vision and the resting mechanism of distance vision based on the hyperfocal distance,and considers that when human eye transfer into the accommodation of near vision from the normal distance vision of hyperfocal distance.There are three different pushing forces contributing to lens deformation and its anterior shift,and these forces cause four different accommodative efforts,which constitute the real accommodative efforts in the relative tissue.This paper also points out that it is only the mode of pushing accommodation that can make the lens vary refraction quickly and greatly,and control the amount of deformation effectively.That can not be achieved by the stretching mode proposed by Tscherning & Schachar,because some authors have verified that excessive pulling would result in decline in the refraction,which would be difficult to regulate and control the eye.Similarly,the self-bulging mode of Helmholtz & Gullstrand will not work neither,because it is unable to control the amount of lens deformation that is its fatal defect. Key words: Accommodation; Hyperfocal; Emmetropia; Lens; Ciliary muscle; Zonule; Iris; Pupil; Depth of focus; Dark focus

Debate on the advantages and disadvantages of multifocal and monofocal intraocular lens

Phacoemulsification and intraocular lens implantation is the most effective treatment of cataract.Traditional intraocular lens were mainly monofocal. Postoperative patients can return to a certain distance vision or near vision, but because of the loss of accommodative power, patients must rely on glasses to complete the work of the different distances, the postoperative life there is still a lot of inconvenience. In recent years, the design of multifocal intraocular lens has been the focus of basic and applied research in cataract, but so far the researchers still could not have agreement with the strengths and weaknesses of the multifocal and monofocal intraocular lens. There are three major controversies: First of all, whether it is worth the expense of contrast sensitivity and increased visual disturbance in return for compensatory adjustment? Second, whether it is possible to really get the full range of vision and to get rid of dependence on glasses to use multifocal intraocular lens? Third, how to grasp the indications of multifocal intraocular lens to play to their strengths.