PresbyLASIK Techniques and Outcomes

Non-dominant eye responses in the dorsal lateral geniculate nucleus of the cat: an intracellular study

PurposeTo report the visual outcomes of the femtosecond laser-assisted multifocal aspheric corneal ablation profile using a mini-monovision approach and to evaluate if corneal multifocality was effective, and to report the relative benefits of this approach.Patients and methodsBilateral femtosecond laser-assisted in situ keratomileusis using a multifocal aspheric corneal ablation profile was performed on 19 hyperopic patients (38 eyes). They were divided into two groups based on eye dominance: dominant eye (DE) group targeting emmetropia and the nondominant eye (NDE) group targeting −0.5 D slight myopia. The uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), and retreatment rates were reported from baseline to 6 months.ResultsThe UNVA, UIVA, and UDVA improved significantly in both groups (Kruskal–Wallis test, DE and NDE: P<0.00001, P<0.000005, and P=0.00001, respectively). Corrected distance visual acuity (CDVA) baseline was better in both groups in comparison to UDVA at 6 months (Wilcoxon test, DE: P<0.001, 95% confidence interval (CI) of the median 0.0–0.0 LogMAR and 0.1000–0.1218 LogMAR and NDE: P=0.010, 95% CI of the median 0.0–0.0 LogMAR and 0.00–0.10 LogMAR). There was a significant loss of lines between CDVA baseline and UDVA at 6 months in both groups (DE group: 68% of eyes lost one line or more; NDE group: 58% of eyes lost one line or more). The corrected near visual acuity baseline compared to UNVA at 6 months was not statistically important (Wilcoxon test, DE: P=0.8125, 95% CI of the median 0.0–0.0 LogMAR and 0.0–0.0 LogMAR and NDE: P=0.82, 95% CI of the median 0.0–0.0 LogMAR and 0.0–0.0 LogMAR). The comparison among the UDVA, UIVA, and UNVA between the two groups at baseline and during all follow-ups was not statistically important. Two cases from the DE group were retreated (6%).ConclusionUse of this multifocal aspheric corneal ablation profile in patients with hyperopic presbyopia significantly improved UDVA, UIVA, and UNVA. This improvement was due to created multifocality of the cornea. The mini-monovision seems not to affect UDVA, UIVA, and UNVA between the two groups. The retreatment rates at the 6-month evaluation were significantly less in our study when compared with other studies. This method seems to improve UDVA, UIVA, and UNVA but could result in a significant statistical difference between CDVA baseline and UDVA at 6 months that leads to loss of lines in distance vision. Despite promising results, this is a preliminary evaluation of this new profile, and a larger number of eyes are needed to verify visual outcomes, retreatment rates, and safety.

To evaluate visual outcomes after bilateral implantation of the RayOne EMV intraocular lens with targeted micromonovision. Southend Private Hospital, Westcliff on Sea, United Kingdom. Retrospective cohort. 50 patients (100 eyes) were assessed at 12 to 18 months postoperatively. Emmetropia was targeted in the dominant eye and myopia of -0.50 to -1.00 diopter (D) in the nondominant eye. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity was assessed monocularly and binocularly at distance (6 m), intermediate (70 cm), and near (40 cm). Defocus was assessed from +1.50 to -4.00 D monocularly and binocularly. Contrast sensitivity was assessed using a computerized Pelli-Robson chart. Mean spherical equivalent was -0.05 ± 0.34 D and -0.91 ± 0.60 D in the dominant and nondominant eyes, respectively. UDVA was significantly different in the dominant (0.09 ± 0.10 logMAR) and nondominant (0.31 ± 0.18 logMAR) eyes ( P < .01). CDVA, distance corrected intermediate VA (DCIVA), and distance corrected near VA (DCNVA) were similar between eyes. However, significant differences were found between binocular uncorrected intermediate VA (UIVA) (0.16 ± 0.11 logMAR) and DCIVA (0.31 ± 0.11 logMAR) ( P < .01) and between binocular uncorrected near VA (UNVA) (0.30 ± 0.17 logMAR) and DCNVA (0.50 ± 0.19 logMAR) also ( P < .01). The nondominant eye shows superior acuity eye in both UIVA ( P < .01) and UNVA ( P < .01). Contrast sensitivity showed no significant difference between eyes ( P = .06). Significant improvement binocularly compared with monocularly was seen through imposed defocus -0.50 to -2.50 D. The RayOne EMV with micromonovision is a reliable method for improving intermediate and near VA, by increasing the range of focus without compromise of distance acuity or contrast sensitivity.

Binocular interaction for a central field was studied with transient scalp visual evoked cortical potentials (VECPs) using two light-emitting-diodes. VECPs were obtained for binocular and monocular visions with dominant and non-dominant eyes, and arithmetical sums of monocular VECPs with dominant and non-dominant eyes were calculated. Amplitude and latency of remarkable initial three peaks were tested with the multivariate analysis of variance. Significant differences were noted among the four VECPs. Pairwise comparisons showed that (1) the amplitude of the first peak for the binocular VECPs was larger than that for the monocular VECPs but smaller than that for the sum-VECPs; the latency of the first peaks for the binocular VECPs were earlier than that for the monocular VECPs with the non-dominant eye; (2) the amplitude of the first negative peak for the sum-VECPs was larger than that for the binocular VECPs, and the peak latency for the sum-VECPs showed later than that for the binocular VECPs; (3) the amplitude of the second positive peak for the binocular VECPs and monocular VECPs with the dominant eye was larger than that with the non-dominant eye, but smaller for the binocular VECPS than that for the sum-VECPs; the latency for the binocular VECPs showed earlier than that for the monocular VECPs with the dominant eye and for the sum-VECPs. Binocular suppression was noted in amplitude for the three peaks and binocular facilitation was noted in latency for the latter two peaks.

Static monocular visual cues can decrease the vestibular-evoked balance response at low frequencies

Objective To investigate the function of accommodation in adolescent myopia and study the differences of accommodation between the dominant and non-dominant eye.Methods Ninety-five subjects (50 myopes,20 emmetropes,25 hyperopes)aged 6～15 years,participated.The accommodative lag and amplitude of accommodation were assessed with their refractive errors corrected.The accommodative lags were assessed using MEM dynamic retinoscopy at 40 cm reading distance.Results 1 there were no significant differences of amplitude of accommodation and accommodative lag between the myopia group and emmetropia group.The differences of amplitude of accommodation between the myopia group and hyperopia group were significant(t=2.21,P=0.03＜0.05;t=2.83,P=0.006＜0.05).2 The difference of accommodative lag between the dominant eye(0.73±0.31)D and non-dominant eyes(0.81±0.38)D in myopia group was significant.3 The accommodative lag of dominant eyes Was(0.68±0.36)D and it of non-dominant eyes Was(0.75±0.34)D,the difference was significant(t=2.06,P=0.042＜0.05,n=95).There was no significant difference between the amplitude of accommodation of dominant eye(12.9±3.09)D and non-dominant eyes(12.6±3.09)D.Conclusion There were no significant differences ofaccommodative lag and amplitude ofaccommodation between the adolescent myopes and emmetropes.The accommodative lag of dominant eyes Was less than it of the non-dominant eye in adolescent.The differences in accommodative function of dominant and non-dominant eyes should be mentioned. Key words: Adolescent; Myopia; Accommodation

Macular thickness, retinal thickness, and optic disk parameters in dominant compared with nondominant eyes

Purpose : The purpose of this study was to measure binocular accommodative response when hyperopic and myopic anisometropia were induced on non-dominatn eye.Methods : Twenty participants (mean age: 24.05±1.73) who had corrected visual acuity more than 0.0 logMAR and no eye disease or systemic disease were recruited. The contact lenses with +1.00, +2.00, -1.00, -2.00 D were monocularly worn on non-dominant eye. The accommodative responses were measured by a binocular open-field autorefractometer when participant fixates target (accommodative stimulus) at 300, 40, and 20 cm.Results : As the accommodative stimulus distance decreased, the amount of accommodative response increased in both eyes (p<0.050). There was significant difference of accommodative responses by different degree of anisometropia (p<0.050). When –2.00 D hyperopic anisometropia was induced, both eyes showed the highest accommodative responses at 40 cm (dominant eye 1.50±0.11 D, non dominant-eye 1.71±0.09 D). When comparing accommodative responses by the type of anisometropia, there was a significant differences in both the dominant and nondominant eyes at 20 cm when inducing 1.00 and 2.00 D in myopic and hyperopic anisometropia (p<0.050). At 40 cm, there was a significant differences in both the dominant and non-dominant eyes when inducing 1.00 in myopic and hyperopic anisometropia (p<0.050). In addition it showed that the higher the degree of myopia and hyperopia, the higher the difference in accommodative response on both eyes and the difference was significant between 40 and 20 cm (p<0.050).Conclusion : There is a difference in the amount of accommodative response between dominant and non-dominant eye when anisometropia was induced. Regardless of the type, the environment that causes the difference in the amount of accommodative response between both eyes causes eye fatigue, so to prevent such a situation, not only the examination on accommodative response of both eyes, but also regular and continuous management is necessary. Also, a prescription for glasses and addition considering the difference between the two eyes is required.

To investigate the outcomes of unilateral Supracor treatment to enhance near vision while maintaining good distance vision in hyperopic eyes. This prospective interventional study includes consecutive hyperopic patients with presbyopia. All eyes underwent femtosecond laser-assisted in situ keratomileusis treatment for hyperopia with an additional Supracor multifocal treatment algorithm in nondominant eyes. Monocular and binocular uncorrected and spectacle-corrected distance visual acuity (UCDVA and SCDVA), monocular and binocular uncorrected near visual acuity (UNVA), and distance-corrected near visual acuity at 40 cm and high-order aberration changes and complications were evaluated for 6 months. Sixty-four patients with a mean age of 51.91 ± 3.64 were enrolled. After 6-month follow-up, the mean binocular UCDVA and UNVA were 0.03 ± 0.05 and 0.04 ± 0.06 logMAR, respectively. UCDVA (logMAR) of nondominant and dominant eyes was 0.30 ± 0.18 and 0.03 ± 0.05, respectively. Preoperative and postoperative mean ± standard deviation manifest refraction spherical equivalent was +1.84 ± 0.75 and -0.48 ± 0.57, respectively, in nondominant eyes and +1.77 ± 0.69 and +0.12 ± 0.33, respectively, in dominant eyes. No complications were observed. Supracor procedure in nondominant eyes may improve functional near, intermediate, and distance vision without significant photic phenomena in presbyopic patients with low and moderate hyperopia.

User-centered design questions in gaze interfaces have been explored in multitude empirical investigations. Interestingly, the question of what eye should be the input device has never been studied. We compared tracking accuracy between the “cyclopean” (i.e., midpoint between eyes) dominant and non-dominant eye. In two experiments, participants performed tracking tasks. In Experiment 1, participants did not use a crosshair. Results showed that mean distance from target was smaller with cyclopean than with dominant or non-dominant eyes. In Experiment 2, participants controlled a crosshair with their cyclopean, dominant and non-dominant eye intermittently and had to align the crosshair with the target. Overall tracking accuracy was highest with cyclopean eye, yet similar between cyclopean and dominant eye in the second half of the experiment. From a theoretical viewpoint, our findings correspond with the cyclopean eye theory of egocentric direction and provide indication for eye dominance, in accordance with the hemispheric laterality approach. From a practical viewpoint, we show that what eye to use as input should be a design consideration in gaze interfaces.

We questioned 104 consecutive eye casualty patients about any visual disturbance experienced while wearing an eye patch as part of their treatment. Many (31%) reported momentary loss of vision in the uncovered eye. Some experienced this while driving. It was more common (p < 0.0008) if the 'dominant eye' had been patched (47%) rather than the 'non-dominant eye' (16%). In a separate experiment, a number of co-operative subjects were provided with a translucent-coloured occluder to be worn over each eye in turn. They reported a recurring coloured interference in the uncovered eye sparing the monocular crescent. We propose that the loss of vision in the unpatched eye is due to binocular rivalry suppression by the patched eye. This visual disturbance may be a cause of anxiety or risk for the patient. Patched patients should be warned this may occur, and advised to avoid driving or operating machinery.

Objective To evaluate the visual outcome of modified monocular prcsbyLASIK (laser in situ keratomileusis) for myopia,astigmatism and presbyopia using Custom-Q software.Methods It was a prospective case series study.Ten myopic patients with presbyopia,40 years or older,underwent monocular presbyLASIK from June 2009 to February 2010,whereby the dominant eyes were corrected for distance with conventional wavefront optimized LASIK and the non-dominant eyes were corrected for near vision with individually adjusted aspheric,Q-value guided ablations.The visual results were described at each postoperative visit (I week,1 month,3 months,6 months and 1 year).Questionnaires were used to characterize patient ocular conditions before surgery and satisfaction with improved monocular prosbyLASIK postoperatively.Analysis of variance,paired t test and Wilcoxon-rank sum test were used for data statistics.Results ①Both postoperative distance uncorrected visual acuity (UCVA) and near UCVA in the non-dominant eye and binocular vision were better after surgery,and the differences were significant (P＜0.01).②Stability:after surgery,the differences in postoperative distance UCVA and near UCVA in the binocular vision at the different time points were not significant.③Safety:the operations were successful and there were no complications.Postoperative best corrected visual acuity (BCVA) in the non-dominant eye did not decrease.④Satisfaction:the patient subjective satisfaction score was 8.40±0.88.The questionnaire indicated that preoperative and postoperative satisfaction with spectacle dependency differed (Z=-2.527.-2.609,P＜0.05).Conclusion This improved monocular presbyLASIK procedure using Custom-Q ablation may be a valuable option for presbyopic individuals considering refractive surgery.Visual results,safety,stability and satisfaction were excellent. Key words: Presbyopia; Vision,monocular; Custom-Q; Keratomileusis,laser in situ

Background and aim Presbyopia is a refractive disorder associated with aging, marked by the gradual loss of the eye’s capacity to focus on close-range objects, typically beginning between 40 and 45 years of age. To address this, laser-assisted in situ keratomileusis (LASIK) has been adapted with advanced techniques such as the Supracor and PresbyMax algorithms, which modify corneal topography by creating a central elevation for near vision and a flatter periphery for intermediate and distance vision. We aimed to evaluate the effectiveness and safety of Supracor LASIK in improving both near and distance vision. Patients and methods A prospective controlled clinical trial was conducted, involving 30 eyes treated with Supracor refractive surgery. Preoperative and postoperative assessments were performed to measure visual outcomes. Results Postoperative evaluations revealed significant enhancements in distance vision for both dominant and nondominant eyes, as well as improved binocular near and distance visual acuity. A small percentage of nondominant eyes experienced slight vision loss (3.3% lost two lines, 13.3% lost one line), while no such decline was observed in dominant eyes. Patient satisfaction was favorable, with average scores of 2.73±1.20 for near vision and 4.40±0.62 for distance vision without glasses. Conclusion Supracor LASIK is an effective option for hyperopic patients with presbyopia. Successful outcomes depend on thorough preoperative assessment and personalized treatment planning, considering the patient’s adaptability to monovision. Proper patient counseling regarding potential risks, such as minor vision loss or the need for enhancements, is essential.

Ocular dominance

Visual fatigue induced by watching virtual reality device and the effect of anisometropia