Sighting dominance and monovision distance binocular fusional ranges.

Clinicians typically apply the distance correction to the dominant sighting eye in fitting presbyopic patients with monovision (MV) contact lenses. We evaluated the effect of this fitting strategy on distance binocular fusional ranges for 23 presbyopic subjects. This sample was composed of successful and unsuccessful MV wearers. Fusional ranges for the two MV fitting possibilities (distance lens on the dominant eye, near lens on the dominant eye) were compared to fusional ranges in which both eyes were fitted with the distance correction. A greater esophoric shift and greater reduction in vergence ranges were demonstrated when the non-dominant eye received the clear image compared to when the dominant eye received the clear image. Successful MV patients demonstrated these effects to a lesser degree than did unsuccessful patients. In general, effects of MV on distance binocular fusional ranges were fewer when successful MV subjects received the clear image in the dominant eye.     

Ocular dominance and the interocular suppression of blur in monovision

Presbyopic contact lens patients with monocular corrections (monovision) see clearly at all distances by virtue of an interocular suppression of anisometropic blur that occurs regionally between corresponding retinal areas. This suppression fails to occur with small high-contrast targets viewed under low luminance conditions. The effect of target size and contrast upon interocular suppression of blur was quantified by reducing contrast of a bright test spot, viewed binocularly while wearing various plus lenses monocularly, until the out-of-focus image was suppressed. The strength of interocular suppression was equivalent when the plus lens was before either eye. However, after subjects wore a plus lens over their nonsighting eye for one day, interocular suppression of blur became enhanced when the nonsighting eye was blurred, and it became reduced when the sighting eye was blurred. Successful monovision subjects suppressed blur at higher contrast levels than did unsuccessful subjects. These results suggest a possible clinical test for quantifying adaptation to monovision.     

Ocular dominance and patient satisfaction after monovision induced by intraocular lens implantation

PURPOSE: To elucidate the relationship between ocular dominance and patient satisfaction with monovision induced by intraocular lens implantation. SETTING: Eye Clinic, Kitasato University School of Medicine Hospital, Sagamihara, Kanagawa, Japan. METHODS: The durations of exclusive visibility of dominant- and nondominant-eye targets were measured in 16 patients with successful monovision and 4 patients with unsuccessful monovision to determine the characteristics of ocular dominance. The dominant eye was determined using the hole-in-card test (sighting dominance). The contrast of target in nondominant eye was fixed at 100%; the contrast of target in the dominant eye varied (ie, 100% to 80% to 60% to 40% to 20%) using rectangular gratings of 2 cycles per degree that were 4 degrees in size. RESULTS: In the successful monovision group, the reversal thresholds (ie, exclusive visibility of the nondominant eye crosses over that of the dominant eye) were displayed only at low decreasing contrast (80% and 60%). However, in the unsuccessful monovision group, the reversal thresholds were at high decreasing contrast (20%) or not at all. The reversal thresholds in patients with unsuccessful monovision were at a significantly lower contrast than in patients with successful monovision (P<.05). CONCLUSIONS: Success and patient satisfaction in monovision patients were significantly influenced by the magnitude of ocular dominance. The balance technique seems to be a good method to evaluate the quantity of ocular dominance and prospectively evaluate the monovision technique.     

Patterns of binocular suppression and accommodation in monovision

The binocular depth of focus of monovision wearers was compared to the sum of the two monocularly determined depths of focus. Observers fell into three groups based upon ocular sighting dominance. Complete binocular summation of the monocular depths of focus was observed in subjects without a preferred fixating eye. Subjects who preferred to fixate with one eye had difficulty suppressing blur of that eye while the binocular target was within the depth of focus of the nonpreferred eye. A third group showed partial summation of the two monocular depths of focus. Similar patterns of accommodative response, measured objectively with the SRI optometer, were observed in subjects wearing monovision corrections. Accommodative response to sinusoidal variations in blur was controlled primarily by the dominant sighting eye. These results demonstrate the effectiveness of interocular suppression of anisometropic blur in monovision correction and the influence of ocular dominance upon this suppression process.     

Monovision pseudophakia

PURPOSE: To evaluate distance and near binocular visual acuities and patient acceptability after sequential posterior chamber intraocular lens (PC IOL) implantation for pseudophakic monovision correction. SETTING: Private practice and the Manhattan Eye Ear and Throat Hospital, New York, New York, USA. METHODS: This study comprised 140 binocular patients with less than 2.00 diopters (D) of astigmatism. Preoperatively, all patients expressed a desire to be independent of optical correction; 120 presented for removal of visually significant cataract and 20, for correction of high ametropia (+8.00 to -14.00 D). Phacoemulsification and implantation of a PC IOL calculated to achieve emmetropia were performed in the dominant eye. Ocular dominance was confirmed on multiple preoperative visits using a sighting technique. Implantation of a PC IOL calculated to yield a spherical equivalent of -2.75 D was performed in the nondominant eye. Seven postoperative examinations were performed during the 1-year follow-up, with 96 patients completing all evaluations. At each examination, interviews were conducted on patient acceptance and ability to perform near and distance tasks without correction. RESULTS: In the entire study group, 129 patients (92%) achieved 20/30 or better uncorrected distance acuity, J1 or better uncorrected near acuity, or both. One hundred ten patients (91%) in the cataract group and 19 (95%) in the clear lens group achieved this level. Patient acceptance was 90% in the cataract group and 100% in the clear lens group. CONCLUSIONS: In a diverse group of self-selected patients from 1 metropolitan-area ophthalmology practice who were motivated to be free of spectacles, pseudophakic monovision provided a high level of satisfaction. No morbidity was associated with monovision as those who were dissatisfied with their uncorrected state did well with spectacle or contact lens correction.     

The influence of ocular dominance on monovision--the interaction between binocular visual functions and the state of dominant eye's correction

PURPOSE: To examine the interaction between binocular visual functions and the correction of the dominant eye, i.e., for far vs. near vision in monovision. SUBJECTS AND METHODS: Ten healthy subjects without any ophthalmological disease were examined. After cycloplegia, the eyes of the subjects were corrected by soft contact lenses (difference in lens power between the lenses: 2.5 D) with an artificial pupil(diameter: 3.0 mm). Visual acuity at various distances, contrast sensitivity, and near stereoacuity were measured while the dominant eye determined by the hole-in-card test (sighting dominance) was corrected for far and near vision. RESULTS: Binocular visual acuity was better than 1.0(20/20) at all distances. When the dominant eye was corrected for distance, the binocular visual acuity at 0.7 m was better than the monocular visual acuity; contrast sensitivity was better within the spatial frequency range of 0.5-4.0 cycles per degree, and near stereoacuity by Titmus stereo tests improved. CONCLUSION: These results suggest that dominant eyes should be corrected for far vision for better binocular summation at middle distances, and near stereoacuity.     

The influence of ocular dominance on monovision--the influence of strength of ocular dominance on visual functions

PURPOSE: Monovision is a method of correction for presbyopia. We have reported the advantage of conventional monovision (the dominant eye is corrected for distance). In this study, we investigated the influence of interocular imbalance of dominancy on the visual function. SUBJECTS AND METHODS: Ten healthy subjects without any ophthalmologic disease participated. After cycloplegia, the eyes of the subjects were corrected by soft contact lenses with an artificial pupil (diameter: 3.0mm). The dominant eye was corrected for distance, and the difference in lens power between the lenses was 2.5 D. The subjects were classified into two groups by strength of the imbalance of sensory dominance, which was determined by using binocular rivalry. Binocular visual functions (visual acuity at various distances, contrast sensitivity, near stereoacuity) were compared between the two groups. RESULTS: Subjects with strong imbalance of sensory dominance showed decreased near visual acuity as well as decreased binocular summation of contrast sensitivity at low spatial frequencies. On the other hand, near stereoacuity was not affected by the imbalance of sensory dominance. CONCLUSION: These results suggest that strong imbalance of sensory dominance interferes with binocular visual functions in monovision. Thus, the evaluation of ocular dominance is crucial for clinical applications of monovision.     

Factors influencing interocular blur suppression

An Important feauture of monovision correction is the ability of the binocular system to suppress blur from the defocused eye (interocular blur suppression). We conducted a study with three subjects and found that interocular blur suppression improved with higher levels of monocular defocus (addition powers in monovision) but was not affected by the eye defocused (sighting dominant or non-domninant) or by pupil size. The selection and management of monovision patients may be assisted by an understading of the understanding of the underlying suppression preocesses.     

Factors influencing success of monovision contact lens fitting: survey of contact lens diplomates.

BACKGROUND: Contact lenses are frequently fitted so that one eye is focused for distance and the other for near (monovision) in order to reduce the dependence of presbyopic patients on bifocal spectacle correction. METHODS: We surveyed Diplomates in the Cornea and Contact Lens section of the American Academy of Optometry (N = 179) regarding their estimates of success with monovision fitting and factors influencing their perception of success. Results were statistically analyzed to determine the fitting philosophies of responders estimating that they achieve high success rates (HSRs) and low success rates (LSRs), respectively. RESULTS: Completed surveys were returned by 98 Diplomates (54.8%), who estimated an overall success rate of approximately 71.7% with monovision; 50.5% "totally successful" (wear monovision correction full-time without problems or need for additional correction) and 21.2% "successful" (wear monovision full-time, but experience some symptoms of blur or other discomfort, may wear over-correction at times for driving or detailed near work). Sighting dominance was the most frequently used method to determine the distant eye, followed by the plus-lens test. The HSR group tended to be more likely to take occupational factors into account when deciding which eye to use for the distance lens, and they used more flexibility in determining the near-add power. The LSR group discontinued monovision sooner than the HSR group, who continued treatment for longer than 4 weeks during the adaptation period much more often for all add ranges. CONCLUSIONS: Practitioners who regard monovision treatment as very successful have somewhat different fitting philosophies than those who regard monovision as unsuccessful. Implementation of highly successful practitioners' fitting techniques may increase success with monovision contact lens fitting.     

优势眼分型及临床研究进展

根据检查方法不同,优势眼可以分为注视性优势眼、运动性优势眼和知觉性优势眼。注视性优势眼主要与视觉方向及定位相关,运动性优势眼主要与双眼注视视差及融合功能相关,知觉性优势眼主要与双眼竞争相关。前两者主要是定性概念,而知觉性优势眼可以通过心理物理学方法对双眼优势差异进行量化研究。优势眼检查方法结果相互之间缺乏一致性,原因目前尚未得知,推测可能大部分正常人群本来就不具有稳定的优势眼。有研究推测单眼视疗法的成功与否不在于选择注视性优势眼矫正看远或看近,而可能取决于双眼知觉性优势差异的大小。关于不同类型优势眼在单眼视疗法中所起的作用,以及优势眼与屈光不正,特别是近视发展的关系,还需要进一步研究证实。     

Effects of dominant and nondominant eyes in binocular rivalry.

PURPOSE: To investigate the relation between sighting and sensory eye dominance and attempt to quantitatively examine eye dominance using a balance technique based on binocular rivalry. METHODS: The durations of exclusive visibility of the dominant and nondominant eye target in binocular rivalry were measured in 14 subjects. The dominant eye was determined by using the hole-in-card test (sighting dominance). In study 1, contrast of the target in one eye was fixed at 100% and contrast of the target in the other eye was varied from 100% to 80% to 60% to 40% to 20%, when using rectangular gratings of 1, 2, and 4 cycles per degree (cpd) at 2 degrees, 4 degrees , and 8 degrees in size. In study 2, contrast of the target in the nondominant eye was fixed at 100% and contrast of the target in the dominant eye was varied from 100% to 80% to 60% to 40% to 20%, when using a rectangular grating of 2 cpd at 4 degrees in size. RESULTS: In study 1, the total duration of exclusive visibilities of the dominant eye target; that is, the target seen by the eye that had sighting dominance was longer compared with that of the nondominant eye target. When using rectangular gratings of 4 cpd, mean total duration of exclusive visibility of the dominant eye target was statistically longer than that of the nondominant eye target (p < 0.05). In study 2, reversals (in which duration of exclusive visibility of the nondominant eye becomes longer than the dominant eye when the contrast of the dominant eye target is decreased) were observed for all contrasts except for 100%. CONCLUSIONS: The dominant sighting eye identified by the hole-in-card test coincided with the dominant eye as determined by binocular rivalry. The contrast at which reversal occurs indicates the balance point of dominance and seems to be a useful quantitative indicator of eye dominance to clinical applications.     

Change in refractive anisometropia in presbyopic adults wearing monovision contact lens correction.

BACKGROUND: Researchers studying the refractive development of infant monkeys suggest that monocular refractive error changes in response to induced ametropia; specifically, slightly blurring one eye may cause a difference to develop between each eye's correction (anisometropia) when none existed before wearing the correction. The important question of whether similar changes occur in humans has not been addressed. METHODS: We compared premonovision correction and the correction after at least 12 months of monovision soft contact lens wear (artificially induced anisometropia prescribed to focus one eye for near and the other for distance so that bifocal glasses are not needed) for 62 healthy predominantly female soft contact lens wearers and (a) 62 age- and sex-matched spectacle wearers and (b) 62 age- and generally sex-matched contact lens wearers. Control patients wore corrections of like power and had similar follow-up periods. RESULTS: Development of anisometropia occurred significantly more frequently among monovision wearers than among spectacle (p = 0.043) or contact lens wearing controls (p = 0.025). Changes in anisometropia greater than or equal to 0.50 D, with amounts up to 1.25 D, occurred in 29% of monovision wearers. CONCLUSIONS: Changes in refractive correction occur for adults who have monocular blur intentionally induced with monovision contact lenses. Similar changes may also occur after refractive surgery if one eye is corrected for a different distance than the other. Care should be taken when counseling presbyopic patients so that they are aware of the possibility of inducing refractive changes after monovision correction.     

间歇性外斜视青少年不同类型优势眼与注视眼的关系

探讨间歇性外斜视（IXT）青少年不同类型优势眼与注视眼（非偏斜眼）的关系。方法：系列病例研究。选取2018年7-12月于湖南爱尔眼视光研究所就诊的IXT青少年患者43例，屈光全矫后分别使用卡洞法测量注视性优势眼，使用集合近点法测量运动性优势眼，使用基于Gabor信号识别的连续闪烁抑制法测量知觉性优势眼，并采用眼位控制力评分观察受检者的远距离客观控制力来判定注视眼。采用Kappa一致性检验比较优势眼与注视眼的一致性，采用单因素Logistic回归分析双眼知觉性优势差异和优势眼与注视眼一致性程度的关系。结果：43例IXT患者中，注视性优势眼、运动性优势眼及知觉性优势眼均与注视眼呈现出中度一致性（Kappa值分别为0.46、0.43、0.68，均 P<0.001）。30例有明确双眼知觉优势差异的患者，其知觉性优势眼与注视眼高度一致（Kappa值= 0.86，P<0.001），而注视性优势眼、运动性优势眼与注视眼的一致性仍为中度一致性（Kappa值= 0.57，P=0.002；Kappa值=0.44，P=0.006）。单因素Logistic回归分析显示IXT患者的双眼知觉性优势差异是知觉性优势眼与注视眼一致性程度的影响因素（B=0.53，OR=1.70，P<0.001），即双眼优势差异越大，知觉性优势眼与注视眼一致性的概率越高。结论：青少年IXT患者的注视性优势眼、运动性优势眼、知觉性优势眼均与注视眼有一致性，但知觉性优势眼与注视眼的一致性更为紧密，尤其当患者有明确知觉优势差异时，知觉性优势眼检查比注视性优势眼和运动性优势眼检查来确定注视眼更为可靠。     

Sighting ocular dominance magnitude varies with test distance

Background

Ocular dominance can be defined as the preference of an individual for viewing with one eye over the other for particular visual tasks. It is relevant to monovision contact lens wear, cataract surgery and sports vision. Clinically, the measurement of ocular dominance is typically done at an arbitrary distance using a sighting test, such as the hole‐in‐card method that has a binary outcome. We investigated the effect of test distance on ocular dominance measured using a binocular sighting test that provided a continuous measurement of dominance.

Methods

Ten participants with normal binocular vision took part in this study. Their binocular sighting ocular dominance and phorias were measured at one, two, four, eight and 10 metres. During the dominance tests participants made a binocular alignment judgment and then were asked to indicate the relative alignment of each eye using a visual analogue scale as a reference.

Results

Eight participants had strong ocular dominance (five right, three left). For these participants, there was a significant increase in the magnitude of dominance with increasing test distance (p < 0.001). This could not be fully explained by changes in convergence demand. Two participants showed very weak ocular dominance across all test distances (p > 0.05), despite changes in convergence demand.

Conclusion

When ocular dominance is present, its magnitude varies significantly with test distance. This has significant implications for the accurate measurement of ocular dominance in the clinic and may reflect the neural processes that influence eye preference.

     

Effects of ocular dominance on binocular summation after monocular reading adds

PURPOSE: To investigate the relationship between ocular dominance and binocular summation with monocular reading adds. SETTING: Department of Orthoptics and Visual Science, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, Japan. METHODS: Contrast sensitivities were measured by having subjects view contrast charts at spatial frequencies of 1.5, 3.0, 6.0, 12.0, and 18.0 cycles per degree after the addition of positive spherical lenses that ranged from +1.0 to +3.0 diopters (D). Through the use of a balance technique, the test group was quantitatively divided into 12 weak and 8 strong ocular dominance subjects on the basis of binocular rivalry. In study 1, binocular contrast sensitivity was measured in the weak and strong ocular dominances by adding a positive spherical lens in front of 1 eye, whereas the other eye was fixed at a corrected distance. RESULTS: In study 1, the binocular summation was observed only after adding positive spherical lenses in the nondominant eye. The differences in binocular contrast sensitivity that occurred after adding a positive spherical lens in the dominant eye versus that seen in the nondominant eye were statistically significant in the strong ocular dominance subjects who had +1.5 D and +2.0 D defocuses (P<.05; analysis of variance). CONCLUSIONS: Binocular summation was effectively maintained with reading adds in the nondominant eye and was significantly influenced by the magnitude of ocular dominance. Evaluating binocular summation after monocular reading adds seems to be a good method to evaluate adaptability to monovision.     

Monovision: a review

In presbyopia, patients can no longer obtain clear vision at distance and near. Monovision is a method of correcting presbyopia where one eye is focussed for distance vision and the other for near. Monovision is a fairly common method of correcting presbyopia with contact lenses and has received renewed interest with the increase in refractive surgery. The present paper is a review of the literature on monovision. The success rate of monovision in adapted contact lens wearers is 59-67%. The main limitations are problems with suppressing the blurred image when driving at night and the need for a third focal length, for example with computer screens at intermediate distances. Stereopsis is impaired in monovision, but most patients do not seem to notice this. These limitations highlight the need to take account of occupational factors. Monovision could cause a binocular vision anomaly to decompensate, so the pre-fitting screening should include an assessment of orthoptic function. Various methods have been used to determine which eye should be given the distance vision contact lens and the literature on tests of ocular dominance is reviewed. It is concluded that tests of blur suppression are most likely to be relevant, but that ocular dominance is not fixed but is rather a fluid, adaptive, phenomenon in most patients. Suitable patients can often be given trial lenses that allow them to experiment with monovision in real world situations and this can be a useful way of revealing the preferred eye for each distance. Of course, no patient should drive or operate machinery until successfully adapted to monovision. Surgically induced monovision is less easily reversed than contact lens-induced monovision, and is only appropriate after a successful trial of monovision with contact lenses.     

The effect of monovision contact lens wear on driving performance

Background : A number of studies have highlighted the problems with driving reported by wearers of monovision contact lens corrections. In this study, we wished to investigate this further, by determining whether driving performance as measured on the open road under daytime conditions is worse when drivers wear their monovision contact lenses compared to their habitual correction. Methods : Thirteen subjects with healthy eyes and corrected visual acuity of 6/6 were selected. Each had worn monovision contact lenses for at least three months. All subjects had their driving performance assessed while driving their own vehicles on an open road course, with both monovision contact lenses and their other habitual correction (spectacles or unaided). Results : No statistically significant differences were found in driving performance when subjects wore their monovision contact lenses compared to when they wore their habitual distance correction. Conclusions : The results indicate that monovision does not adversely affect driving performance in daylight hours for adapted wearers. However, limitations in the study design are acknowledged, including the relatively small sample size, lack of standardisation of the habitual correction and the use of adapted wearers. Future studies are recommended to investigate these issues further.     

The Quest for Spectacle Independence: A Comparison of Multifocal Intraocular Lens Implants and Pseudophakic Monovision for Patients with Presbyopia

ABSTRACT

We performed a literature review comparing multifocal intraocular lens (IOL) implantation with pseudophakic monovision to treat presbyopia. Multifocal IOLs utilize refractive or diffractive principles to treat both distance and near vision, with a single lens implant. Monovision uses traditional monofocal lens implants to treat the dominant eye for emmotropia, and the non-dominant eye for myopia. This planned anisometropia is designed to enhance intermediate or near vision. Generally, distance vision was similar with both types of lens implantation, near vision was better with multifocal IOLs, and intermediate vision appeared to be better in the monovision group. For patients requiring cataract surgery, both multifocal IOLs and monovision appear to address presbyopia with a high level of patient satisfaction. More patients reported complete spectacle independence with multifocal IOLs, but more glare and halos were reported by multifocal IOL patients as well.     

Sensory ocular dominance based on resolution acuity,contrast sensitivity and alignment sensitivity

Background: Ocular dominance is the superiority or preference of one eye over the other in terms of sighting, sensory function (for example, visual acuity) or persistence in binocular rivalry. There is poor agreement between sighting and sensory dominance and findings are equivocal on the possible neural basis of ocular dominance and its significance. Thus, there are questions on the meaning and importance of ocular dominance. Despite the lack of clarity in this area, ocular dominance is used clinically, for example, as the basis for decisions on monovision in contact lens wear and on treatment of anomalies of binocular vision. Methods: Sighting dominance and three types of sensory dominance (based on resolution acuity, contrast sensitivity and alignment sensitivity) were compared within individuals, with the main aim of determining whether sensory dominance is consistent across spatial visual functions. Results: Our findings indicate that each type of sensory dominance is insignificant in most individuals and in agreement with previous work that sensory and sighting dominance do not generally agree. Conclusion: These results demonstrate not only that different types of ocular dominance are not in agreement but also that in the normal visual system sensory dominance as measured here is insignificant in most individuals with normal vision.