Comparison of multifocal and monovision soft contact lens corrections in patients with low-astigmatic presbyopia.

PURPOSE: The purpose of this study was to assess visual performance and patient satisfaction with two presbyopic soft contact lens modalities. METHODS: A crossover study of 38 patients with presbyopia was conducted. Patients were randomized first into either multifocal (Bausch & Lomb SofLens Multifocal) or monovision (SofLens 59) for 1 month. Visual performance was measured with high- and low-contrast visual acuity at distance and near and near stereoacuity. Patients' satisfaction was measured by the National Eye Institute Refractive Error Quality of Life Instrument questionnaire and by recording the patient's final lens preference. RESULTS: Patients maintained at least 20/20 binocular vision with both multifocal (MF) and monovision (MV) contact lenses under high-contrast conditions at distance and near. Under low-contrast conditions, patients lost less than a line of vision from the best spectacle correction to either multifocal or monovision contact lens correction at distance (pMF = 0.001, pMV = 0.006). Under low-contrast conditions at near, multifocal wearers lost five to six letters and monovision wearers lost two letters of vision (pMF < 0.001, pMV = 0.03, pMF/MV = 0.005). The average stereoacuity decreased by 79 s arc with monovision vs. multifocal contact lenses (p = 0.002). On the NEI-RQL, patients reported worse clarity of vision (pMF = 0.01, pMV < 0.001), more symptoms (pMF = 0.09, pMV = 0.01), and an improvement in their appearance with contact lens wear (pMF < 0.001, pMV < 0.001). Seventy-six percent of patients reported that they preferred multifocal contact lenses, and 24% preferred monovision contact lenses (p = 0.001). CONCLUSION: The majority of our patients preferred multifocals to monovision, most likely because the Bausch & Lomb SofLens Multifocal provides excellent visual acuity without compromising stereoacuity to the same degree as monovision.     

Comparative visual performance of three presbyopic contact lens corrections.

We compared the visual performance of a soft diffractive (DIFF) bifocal contact lens, a near center (CN) concentric bifocal design, and monovision (MV), using a comprehensive vision testing protocol. Fifteen presbyopic subjects who were successfully wearing DIFF bifocal contact lenses participated in the study. Of the three systems tested, MV provided best visual acuity at distance and near; less than one line of acuity was lost relative to best spectacle acuity under all lighting and contrast conditions, and there was less disturbance of a point source of light. Both bifocal corrections gave similar visual acuity performance, with more lines of acuity lost relative to spectacles at near compared to distance. However, the concentric bifocal induced more ghosting at near than the other two systems. Stereopsis was compromised at distance with MV correction, but all systems performed worse than spectacles at near. An understanding of the strengths and weaknesses of presbyopic contact lens options allows the clinician to improve management of the presbyope who wishes to wear contact lenses.     

Role of visual acuity, stereoacuity, and ocular dominance in monovision patient success.

Monovision (MV) contact lens correction of presbyopia induces substantial reductions in stereoacuity and small reductions in binocular visual acuity (VA). This study examined those effects in a group of successful and a group of unsuccessful MV patients. Compared to performance with a full binocular correction, the unsuccessful group demonstrated significant losses in both functions. These reductions were smaller in the successful group and of marginal statistical significance only for stereoacuity. Laterality of sighting dominance and laterality of distance/near correction had minimal effect on the results.     

Influence of astigmatism on multifocal and monofocal intraocular lenses

PURPOSE: To examine the influence of astigmatism on the visual acuity of patients with multifocal and monofocal intraocular lenses. METHODS: Thirty eyes of 30 patients who underwent five-zone refractive multifocal intraocular lens implantation and 30 eyes of 30 age-matched patients who had monofocal intraocular lens implantation were included. The visual acuities of these patients at 5.0, 3.0, 2.0, 1.0, 0.7, 0.5, and 0.3 m were measured by means of an all-distance vision tester after addition of a cylindrical lens of 0, 0.5, 1.0, 1.5, 2.0, and 2.5 diopters. RESULTS: Mean visual acuity at all distances decreased in proportion to the diopters of astigmatism in both the multifocal and monofocal intraocular lens groups. When astigmatism was 0.5, 1.0, or 1.5 diopters, distance visual acuity in the multifocal group was significantly worse than that in the monofocal group; with astigmatism of 2.0 diopters or more, intermediate visual acuity was also worse in the multifocal group. In contrast, near visual acuity in the multifocal group was significantly better than that in the monofocal group at all astigmatic diopters. When astigmatism was within 1.0 diopter, visual acuity in the multifocal group reached 20/29 at distance and 20/50 at near. Mean contrast sensitivity was also worse in the multifocal group than in the monofocal group. CONCLUSIONS: Both distance and intermediate visual acuity deterioration caused by astigmatism was greater with a multifocal intraocular lens than with a monofocal intraocular lens, whereas near visual acuity was better with the multifocal intraocular lens. When astigmatism was within 1.0 diopter, eyes with a multifocal intraocular lens achieved good visual acuity at both distance and near.     

Comparison of suppression, stereoacuity, and interocular differences in visual acuity in monovision and acuvue bifocal contact lenses.

PURPOSE: The relationship between visual acuity and stereoacuity has been well documented: as binocular visual acuity increases, stereoacuity improves. We compared interocular differences in visual acuity and stereoacuity in two presbyopic soft contact lens modalities, monovision and a new soft bifocal contact lens, the Acuvue Bifocal. The Acuvue Bifocal is hypothesized to show a smaller interocular acuity difference, increased stereoacuity, and decreased suppression over monovision at distance and near. METHODS: Monovision patients wearing Acuvue or Surevue soft contact lenses were tested for visual acuity, stereoacuity, and suppression at distance and near. Stereoacuity was tested with the Randot Stereotest (near) and the BVAT (distance). Suppression was evaluated with the Acuity Suppression Vectogram (near) and the BVAT (distance). Patients were then fit with the Acuvue Bifocal in each eye. After wearing the lenses for 1 week, the same tests of visual acuity, stereoacuity, and suppression were performed. RESULTS: The mean interocular acuity difference (IAD) at distance with monovision was 0.712 logarithm of the minimum angle of resolution (logMAR) (SD = 0.275) and 0.188 logMAR (SD = 0.252) (p < 0.001) with the Acuvue Bifocal. At near, the mean IAD with monovision was 0.420 logMAR (SD = 0.183) and 0.137 logMAR (SD = 0.147) (p < 0.001) with the Acuvue Bifocal. Of the monovision subjects, 89% (17 of 19) demonstrated suppression at near while only 26% (5 of 19) did with the bifocal lenses (statistically significant at p < 0.001). Stereoacuity at near improved from a median of 200 sec arc with monovision to 50 sec arc with the bifocal lenses. CONCLUSIONS: In this study, correcting presbyopia with the Acuvue Bifocal versus monovision resulted in a statistically significant decrease in the interocular difference in visual acuity at distance and near. The decreased interocular difference in visual acuity improved certain aspects of binocularity as demonstrated by a decrease in suppression and an increase in stereoacuity.     

Evaluation of two new soft contact lenses for correction of presbyopia: the Focus Progressives multifocal and the Acuvue Bifocal

The clinical performance of Focus Progressives multifocal contact lenses and Acuvue Bifocal contact lenses was evaluated in a group of 42 presbyopes, with equal numbers of individuals having low, medium, and high spectacle add requirements. Following visual performance assessment with an optimal sphero-cylinder spectacle refractive correction, each individual wore each of the two types of contact lenses in successive random order. Each type of lens was used in a daily-wear mode for a period of 7 to 12 days, with follow-up and/or refitting visits occurring after 2 to 5 days, and again after 4 to 7 days of attempted wear. Testing for all three forms of refractive correction encompassed Snellen acuities at distance and near, Bailey-Lovie acuities under high and/or low ambient illumination conditions at near, intermediate, and far viewing distances, stereoacuity, a timed visuomotor task (needle threading), apparent glare/flare, and the nearwork range of subjectively clear binocular vision. The contact lenses also were evaluated for handling, comfort, distance and near ghosting, subjective visual quality, acceptability for common tasks (e.g., using a phone directory), and personal preferences.As might be expected, distance and near acuity, stereoacuity, and visuomotor task performance were somewhat better with sphero-cylinder spectacle correction than with either of the two types of contact lenses. However, several performance differences between the multifocal and bifocal lenses were noted. The Focus Progressives lenses provided significantly better distance acuity under both high and low illumination conditions, and received significantly higher ratings for visual quality (overall and at distance), comfort, and handling. The Focus Progressives lenses were preferred 5:1 over the Acuvue Bifocal lenses. No differences existed between the lenses with respect to near visual acuities, the perceived quality of the near vision, the nearpoint binocular range, stereoacuity, or the acceptability of vision for common nearwork tasks. The results suggest that although both types of lenses afford presbyopes a viable alternative to spectacles, the Focus Progressives lens is superior in many ways to the Acuvue Bifocal lens.     

Visual acuity in contact lens wearers.

PURPOSE: The difference between high- and low-contrast visual acuity provides a sensitive indicator of vision loss in ocular disease; however, the effect of refractive error correction on this difference is still debated. METHODS: High- and low-contrast visual acuity was measured in 116 rigid gas permeable contact lens wearers, 51 spectacle wearers, and 50 soft contact lens wearers with habitual and best correction. Twenty-nine of the soft contact lens wearers reported that they wore disposable contact lenses (discarded on a monthly or more frequent basis), whereas the other 21 soft contact lens wearers wore traditional soft contact lenses. RESULTS: Rigid gas permeable contact lens wearers had statistically worse high-contrast habitual visual acuity than spectacle wearers (Tukey-Kramer, p = 0.0075). Traditional soft contact lens wearers had significantly worse low-contrast visual acuity compared with all other groups (Tukey-Kramer, p < 0.02 for each comparison). Traditional soft contact lens wearers had a significantly larger difference between high- and low-contrast visual acuity with best correction compared with rigid gas permeable wearers (Tukey-Kramer, p = 0.0099). CONCLUSIONS: Rigid gas permeable contact lens wearers had statistically worse habitual high-contrast visual acuity compared with spectacle wearers, but no difference was present under best-corrected conditions. We hypothesize that rigid gas permeable contact lens wearers were not wearing their optimal correction habitually. Traditional soft contact lens wearers had significantly worse low-contrast visual acuity. They also had a larger difference between their best-corrected high- and low-contrast visual acuity scores compared with rigid gas permeable contact lens wearers.     

Assessment of central and peripheral fusion and near and distance stereoacuity in intermittent exotropic patients before and after strabismus surgery.

PURPOSE: To determine whether central fusion and distance stereoacuity are useful as objective measures in assessing the need for and success of surgery for intermittent exotropia (X[T]). METHODS: A prospective, institutional, clinical trial was conducted of 26 consecutive patients with X(T) who were undergoing strabismus surgery in whom fusion (central and peripheral) and stereoacuity (at near and distance) were assessed preoperatively and postoperatively, as well as in 112 normal subjects. To obtain accurate measurements with sensory tests, the lower age was limited to 5 years for inclusion. A successful surgical alignment was defined as an exotropia of 10 prism diopters or less at 6 m. Sensory and motor outcome measures were determined 1 year after surgery. RESULTS: The successful surgical alignment rate was 69%. All patients with X(T) demonstrated peripheral fusion, whereas 35% demonstrated central suppression preoperatively and postoperatively. Central fusion was not predictive of surgical outcome (P = .078); however, there was a trend toward less surgical success in patients with central suppression. Patients with X(T) exhibited good near stereoacuity before and after surgery. Distance stereoacuity in patients with X(T) preoperatively was significantly diminished compared with normal subjects (P < .001) and was improved in 58% postoperatively. Patients who achieved successful surgical alignment had a greater likelihood of demonstrating distance stereoacuity improvement postoperatively than patients who failed to achieve successful surgical alignment (P = .003). Patients with central suppression were unlikely to improve their distance stereoacuity postoperatively (P = .014). CONCLUSIONS: Successful surgery may improve distance stereoacuity. Better distance stereoacuity and central fusion are frequently associated with better surgical success in X(T).     

AcrySof ReSTOR多焦点人工晶状体植入术后的视功能观察

目的 探讨年龄相关性白内障患者行超声乳化联合AcrySof ReSTOR多焦点人工晶状体（MIOL）植入术后的视功能及视物满意度.方法 回顾性研究.将20例（40眼）植入AcrySof ReSTOR＋3D MIOL患者（观察组）与20例（40眼）植入AcrySof IQ单焦点人工晶状体患者（对照组）进行对比,观察两组患者术后3个月相同光照条件下远、中、近裸眼及最佳矫正视力和立体视锐度;并对术后视物满意度进行问卷调查.所得数据资料的比较采用秩和检验.结果 观察组的裸眼中距视力、远矫正下的中距视力、裸眼近视力、远矫正下的近视力均显著高于对照组（Z=2.978,P＜0.01;Z=3.040,P＜0.01;Z=3.471,P＜0.01;Z=3.098,P＜0.01）.观察组立体视锐度显著高于对照组（Z=2.264,P＜0.05）.观察组中,中距离、近距离视物满意度（96%、100%）明显好于对照组（77%、50%）.结论 双眼植入AcrySof ReSTOR＋3DMIOL患者拥有良好的全程视力以及近立体视锐度,生活质量得到了提高.     

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.     

老年性白内障摘除术后早期双眼视觉的恢复

目的　观察老年性白内障摘除术后早期患者双眼视觉的恢复情况 ,并探讨影响其恢复的原因。方法　对 5 5例 (6 6只眼 )老年性白内障患者行囊外白内障摘除人工晶状体植入术 (ECCE组 )或超声乳化白内障吸除人工晶状体植入术 (PHACO组 ) ,术后检查矫正视力、屈光度数 ,以及双眼同视、融合及远、近距离立体视功能。结果　术前术眼视力ECCE组低于PHACO组 ,差异有显著意义 (P <0 0 5 ) ;术后术眼和非术眼视力两组比较 ,差异均无显著意义 (P >0 0 5 )。术后ECCE组双眼柱镜屈光度数差值较大 ,与PHACO组比较差异有非常显著意义 (P <0 0 1)。两组患者术后均具有较好的双眼同视和融合功能。ECCE组和PHACO组分别有 83 3%和 94 7%的患者获得不同程度的远距离立体视 ,差异无显著意义 (P >0 0 5 ) ;分别有 2 8%和 2 1 1%的患者获得黄斑中心近距离立体视 ,差异有显著意义(P <0 0 5 )。结论　老年性白内障摘除术后早期患者的双眼视觉未完全恢复 ;术前长期的视觉抑制 ,尤其是单眼抑制和术后的屈光参差可能是影响双眼视觉恢复的原因。     

单眼白内障患者植入多焦点人工晶状体与单焦点人工晶状体后的双眼视功能比较

目的比较单眼白内障患者植入多焦点人工晶状体（IOL）或单焦点IOL后的双眼视功能。方法前瞻性非随机对照研究。2013年6月至2014年12月期间,在我院行白内障超声乳化联合IOL植入术的单眼白内障患者80例（80眼）,根据植入的IOL类型分为2组,各40例（40眼）。观察组植入多焦点IOL,对照组植入单焦点IOL。术后随访3个月,观察指标包括术眼单眼及双眼远（5 m）、中（70 cm）、近（40 cm）视力,双眼对比敏感度,近立体视,脱镜率,视觉干扰现象及患者满意度。术后视力及对比敏感度比较采用独立样本t检验;脱镜率及光干扰现象发生率的比较采用χ²检验;近立体视、视力满意度评分比较采用Mann-Whitney U检验。结果观察组双眼裸眼远、中、近视力分别为0.03±0.04、0.17±0.07、0.15±0.06,对照组双眼裸眼远、中、近视力分别为0.05±0.05、0.27±0.08、0.31±0.09,观察组双眼裸眼中视力和近视力优于对照组（t=3.925、3.429,P＜0.01）,而2组间双眼裸眼远视力差异无统计学意义（t=0.356,P＞0.05）。双眼在空间频率为3、6、12、18 c/d时,观察组无眩光对比敏感度和有眩光对比敏感度均低于对照组（无眩光：t=3.463、3.361、2.198、2.574,P＜0.05;有眩光：t=3.105、2.432、2.758、3.207,P＜0.05）。观察组近立体视优于对照组（Z=2.578,P＜0.05）,脱镜率（88%）高于对照组（28%）（χ²=8.240,P＜0.05）,2组间视远满意度评分差异无统计学意义（Z=0.598,P＞0.05）,而观察组视中和视近满意度评分均高于对照组（Z=2.314、3.137,P＜0.05）。2组间视觉干扰眩光现象差异无统计学意义（χ²=0.602,P＞0.05）,而观察组光晕现象多于对照组（χ²=8.807,P＜0.05）。结论单眼白内障患者植入多焦点IOL相比单焦点IOL能提供更好的双眼中、近视力,双眼立体视,脱镜率及患者满意度,但对比敏感度有所降低。     

Prospective clinical evaluation of the Acuvue Bifocal contact lens.

PURPOSE: We conducted a 15-month prospective clinical studyto evaluate the performance of the Acuvue Bifocal contact lens and to determine the objective and subjective factors that influence patient success rates in a general presbyopic population presenting to a contact lens specialist's office. METHODS: The first 100 patients who were initially fit and dispensed the Acuvue Bifocal contact lens are included in this study data. At each follow-up visit, visual acuity, slit lamp evaluation of lens/cornea relationship, and any change in ocular surface characteristics were noted. The study population was a general population with an interest in wearing disposable multifocal contact lenses. Success was defined as the patient actually purchasing the lens for continual wear. RESULTS: The overall success rate with the lens in this diverse study group was 53%. The majority of the successful patients achieved 20/25 or better distance and near acuity with the Acuvue Bifocal. None of the study participants had any adverse effect of lens wear or changes in keratometry or ocular surface characteristics. Of the successful patients, 57% wore the lens in a binocular fashion, while the remainder used some form of monovision. Virtually all patients rated lens comfort as excellent or very good, with the major factor in success or failure being visual performance. CONCLUSIONS: This prospective study in an average group of presbyopic contact lens or spectacle wearers yielded valuable insights into the performance of a disposable multifocal contact lens in a general contact lens practice. The Acuvue Bifocal should prove to be a valuable addition to the contact lens fitter's practice.     

The effect of relative distance enlargement on visual acuity in the visually impaired

Background : Prescribing magnification is typically based on distance or near visual acuity. This presumes a constant minimum angle of visual resolution with working distance and therefore enlargement of an object moved to a shorter working distance (relative distance enlargement). This study examines this premise in a visually impaired population. Methods : Distance letter visual acuity was measured prospectively for 380 low vision patients (distance visual acuity between 0.3 and 2.1 logMAR) over the age of 57 years, along with near word visual acuity at an appropriate distance for near lens additions from +4 D to +20 D. Demographic information, the disease causing low vision, contrast sensitivity, visual field and psychological status were also recorded. Results : Distance letter acuity was significantly related to (r = 0.84) but on average 0.1 ' 0.2 logMAR better (1 ' 2 lines on a logMAR chart) than near word acuity at 25 cm with a +4 D lens addition. In 39.8 per cent of patients, near word acuity was more than 0.1 logMAR worse than distance letter acuity. In 11.0 per cent of subjects, near visual acuity was more than 0.1 logMAR better than distance letter acuity. The group with near word acuity worse than distance letter acuity also had lower contrast sensitivity. The group with near word acuity better than distance letter aculty was less likely to have age‐related macular degeneration. Smaller print size could be read by reducing working distance (achieved by using higher near lens additions) in 86.1 per cent, although not by as much as predicted by geometric progression in 14.5 per cent. Discussion : Although distance letter and near word acuity are highly related, they are on average 1 logMAR line different and this varies significantly between individuals. Near word acuity did not increase linearly with relative distance enlargement in approximately one in seven visually impaired, suggesting that the measurement of visual resolution over a range of working distances will assist appropriate prescribing of magnification aids.     

Visual acuity tolerance to residual refractive errors in patients with an apodized diffractive intraocular lens

PURPOSE: To assess visual acuity tolerance to defocus caused by residual refractive errors after clear lens extraction (CLE) with apodized diffractive intraocular lens (IOL) implantation. SETTING: Fernández-Vega Ophthalmological Institute, Oviedo, Spain. METHODS: In this prospective study, 150 eyes of 75 consecutive patients who had bilateral CLE with implantation of an AcrySof ReSTOR Natural IOL (Alcon) were evaluated. The eyes were divided into 2 groups: myopia and hyperopia. Residual refractive errors were analyzed using vector analysis. Monocular and binocular uncorrected distance visual acuity, best corrected distance visual acuity, uncorrected distance near visual acuity, and best distance-corrected near visual acuity 6 months after surgery were recorded. RESULTS: When the distance residual refractive error was corrected, there was a statistically significant improvement in uncorrected distance acuity in the myopia group and hyperopia group (P<.001). No differences were found between uncorrected-distance near acuity and best distance-corrected near acuity (P>.2). A significant trend toward worse visual acuity as a function of spherical equivalent (SE) value was significant only for uncorrected distance acuity (P<.001). No significant correlations were found for best corrected distance acuity, uncorrected-distance near acuity, and best distance-corrected near acuity as a function of SE (P>.2). CONCLUSIONS: Correction of distance residual refractive error improved distance visual acuity in patients with apodized diffractive IOLs. However, near visual acuity was maintained whether the residual refractive error was corrected or not.     

Stereopsis after Implantation of Intraocular Lens in Patients under 40 Years Old with Unilateral Cataract

 PURPOSE:To investigate the stereopsis after single focus intraocular lens (SIOL) implantation in patients aged <40 years with unilateral cataract. METHODS:In total, 36 patients (36 eyes) were divided into emmetropia and myopia groups. Twenty seven subjects with good uncorrected distance visual acuity (UCDVA) after surgery were enrolled in the emmetropia group. The myopia group consisted of 9 subjects whose one eye had mild myopia postoperatively and the other was emmetropic or myopic. Visual acuity, distance and near stereoacuity were measured post-operatively. RESULTS:In the emmetropia group, uncorrected near visual acuity (UCNVA) did not differ significantly between eyes (t=1.87, P>0.05). The LogMAR UCNVA of the operated and fellow eyes were (0.71±0.12) and (-0.05±0.07, t = 28.4, P<0.001) respectively. Distance stereoacuity was 60"; the near stereoacuity with uncorrected visual acuity and BCNVA in the operated eyes were 200" and 30" respectively (Z=－4.121, P<0.001). In the myopia group, the BCDVA did not differ significantly between the operated and fellow eyes (t =-0.636, P>0.05). The UCNVA of the operated eyes (0.18±0.12) was significantly better compared with that of the fellow eyes (-0.04±0.10, t = 4.2252, P<0.001). The distance stereoacuity with uncorrected visual acuity and BCDVA in the operated eyes were 200" and 60" respectively (Z =-2.371, P<0.05). The near stereoacuity with uncorrected visual acuity was 50". CONCLUSION:For patients with unilateral cataract aged <40 years, stereopsis is closely associated with refractive status after IOL implantation. Near stereoacuity in emmetropic eyes can be improved with refraction, and that in mildly myopic eyes can be enhanced by leaving myopia uncorrected.     

双侧人工晶状体眼立体视的临床观察

目的:观察老年性白内障患者双眼人工晶状体植入术后近立体视的恢复。方法:分为双眼人工晶状体组及正常老年人组,检影验光后测量远矫正下和近矫正下的近视力并应用Randot stereotests图分别检查两种矫正下的近立体视锐度。结果:远矫正下两组的双眼近视力分别是0．51±0．15和0．52±0．17(LogMar),立体视锐度分别是(101±59)弧秒和(112±55)弧秒。近矫正下两组的双眼近视力分别是0．09 0．10和0．11± 0．11,近立体视锐度分别是(33±11)弧秒和(34±10)弧秒,两组间两种矫正下的近视力和近立体视锐度均无差异(P>0．05),两组内近矫正下的近视力和近立体视锐度均明显优于远矫正下(P<0．01)。结论:老年性白内障患者双眼人工晶状体植入术后近立体视锐度可以恢复到正常同龄人水平。     

Stereoacuity with balanced presbyopic contact lenses

Background: To evaluate near stereoacuity with the balanced Proclear Multifocal simultaneous vision contact lens. Methods: Twenty‐five presbyopic subjects were fitted binocularly with the Proclear Multifocal contact lens and with distance contact lenses combined with reading spectacles, which served as controls. After one month, stereoacuity was measured using the vectographic Titmus and Random dot stereotests and the Howard‐Dolman (HD) apparatus under photopic conditions (85 cd/m²) at 40 cm. Binocular high‐contrast visual acuities (BHCVA) at distance and near were examined. Results: For the multifocal group, mean stereoacuity with the Howard‐Dolman method was 22.40 ± 8.23 seconds of arc. Using the Titmus and the Random dot sterereotests, the values were 56.40 ± 18.00 and 54.80 ± 20.23 seconds of arc, respectively. For the SCL group, mean stereoacuities were 19.9 ± 4.6, 51.2 ± 16.4 and 51.2 ± 20.88 seconds of arc, with the Howard‐Dolman, Titmus and the Random dot, respectively. There were no statistically significant differences among groups for Howard‐Dolman (p = 0.07), Titmus (p = 0.10) and Random dot (p = 0.17) stereotests. No statistically significant differences were found between the Titmus and the Random dot stereotest values (multifocal group: p = 0.30 and SCL group: p = 0.50), however, these values differ significantly from those found using the Howard‐Dolman method for both groups (p < 0.001). For the multifocal group, BHCVA was ?0.007 ± 0.060 and 0.012 ± 0.063 logMAR for distance and near vision, respectively. For the SCL group, these values were ?0.02 ± 0.05 and ?0.01 ± 0.06 logMAR, for distance and near vision, respectively. Comparing both groups there were no statistically significant differences between groups for either distance (p = 0.08) or near (p = 0.09). Conclusions: The Proclear Multifocal contact lens provided good distance and near visual acuity preserving stereopsis. Multifocal optics with one lens biased to distance viewing and the other lens biased toward near viewing minimally affects stereoacuity.     

Influence of Test Distance on Stereoacuity in Intermittent Exotropia

Aims: To investigate influence of test distance on stereoacuity in intermittent exotropia (X[T]) using the same test conditions for both near and far distances. Methods: Subjects were 38 consecutive patients with X(T). All the patients were between ages 6 and 15 years and had decimal visual acuity of 1.0 or better. Another inclusion criterion was presence of phoric condition at near and far distances. Stereoacuity was measured at a near distance of 40 cm and at a far distance of 5 m. The following test conditions were used for both test distances: separation of the two eyes using polarized glasses, and a target with a random dot pattern. All the stereograms had the same subtended angle of 2.5º, and binocular disparity of 480, 240, 120, and 60 arcsec. We used two stereogram types with crossed and uncrossed disparities. Results: Far stereoacuity of 38 subjects measured with the crossed disparity was significantly worse than near stereoacuity (P<0.05, Wilcoxon signed-ranks test), although 30 (78.9%) of the 38 subjects showed no differences in stereopsis between the near and far distances. Far stereoacuity of 38 cases measured with the uncrossed disparity was significantly worse than at near (P<0.05, Wilcoxon signed-ranks test), although 20 (52.6%) of the 38 subjects showed no differences between stereoacuity at near and far. In comparison of stereoacuity with crossed disparity and uncrossed disparity, stereoacuity with crossed disparity was significantly better than that with uncrossed disparity both at near and far (P<0.05, Wilcoxon signed-ranks test). Conclusions: Stereoacuity in X(T) was different according to test distance when measured controlling subtended angle of stereogram at both distances. Far stereoacuity was significantly worse than near stereoacuity when measured using test targets with both crossed and uncrossed disparities. Additionally, stereoacuity measured with crossed disparity was better than that with uncrossed disparity at both distances.     

Changes in stereoacuity following implantable Collamer lens implantation in patients with myopia

The study evaluated the impact of implantable Collamer lens (ICL) implantation on stereoacuity in myopes in a retrospective case series. Ninety-five eyes of 48 patients were recruited. Distance and near stereoacuity were measured using distance Randot stereotest and TNO test, respectively, before surgery and at 4 weeks postoperatively. Mean age of the patients was 23.67 ± 3.7 years. Mean uncorrected distance visual acuity (UDVA) was 1.28 ± 0.37 logarithm of the minimum angle of resolution (logMAR) (median: 1.3; range: 0.3–1.8), and median best-corrected distance visual acuity (BDVA) was 0.18 logMAR (range: 0–0.6). There was a significant improvement in both UDVA and BDVA postsurgery (P < 0.001; Wilcoxon signed rank test). The overall improvement in stereopsis was observed in 15/48 (31.25%) and 13/48 (27.10%) subjects for near and distance, respectively, with no significant difference between the two (P = 0.82; Fisher''s exact test). Among stereoblind individuals, the odd''s ratio for near stereoacuity to improve in comparison to distance stereoacuity was 8.85 (95% confidence interval: 1.68–46.70; P = 0.01). ICL implantation for refractive correction aided stereoacuity improvement in myopes more so for near.