Dataset Information

The scotogenic contact lens: a novel device for treating binocular diplopia.

ABSTRACT: Binocular diplopia is a debilitating visual symptom requiring immediate intervention for symptomatic control, whether or not definitive treatment is eventually possible. Where prismatic correction is infeasible, the current standard is occlusion, either by a patch or an opaque contact lens. In eliminating one problem-diplopia-occlusive techniques invariably create another: reduced peripheral vision. Crucially, this is often unnecessary, for the reduced spatial resolution in the periphery limits its contribution to the perception of diplopia. Here, we therefore introduce a novel soft contact lens device that instead creates a monocular central scotoma inversely mirroring the physiological variation in spatial acuity across the monocular visual field, thereby suppressing the diplopia with minimal impact on the periphery. We compared the device against standard eye patching in 12 normal subjects with prism-induced binocular diplopia and 12 patients with binocular diplopia of diverse causes. Indexed by self-reported scores and binocular perimetry, the scotogenic contact lens was comparably effective in eliminating the diplopia while significantly superior in acceptability and its impact on the peripheral visual field. This simple, inexpensive, non-invasive device may thus be an effective new tool in the treatment of a familiar but still troublesome clinical problem.

SUBMITTER: Robert MP

PROVIDER: S-EPMC4518759 | biostudies-literature | 2015 Aug

REPOSITORIES: biostudies-literature

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The scotogenic contact lens: a novel device for treating binocular diplopia.

Robert Matthieu P MP Bonci Fabrizio F Pandit Anand A Ferguson Veronica V Nachev Parashkev P

The British journal of ophthalmology 20150213 8

Binocular diplopia is a debilitating visual symptom requiring immediate intervention for symptomatic control, whether or not definitive treatment is eventually possible. Where prismatic correction is infeasible, the current standard is occlusion, either by a patch or an opaque contact lens. In eliminating one problem-diplopia-occlusive techniques invariably create another: reduced peripheral vision. Crucially, this is often unnecessary, for the reduced spatial resolution in the periphery limits ...[more]

PMID: 25680615

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Project description:Purpose(1) To devise a model-based method for estimating the probabilities of binocular fusion, interocular suppression and diplopia from psychophysical judgements, (2) To map out the way fusion, suppression and diplopia vary with binocular disparity and blur of single edges shown to each eye, (3) To compare the binocular interactions found for edges of the same vs opposite contrast polarity.MethodsTest images were single, horizontal, Gaussian-blurred edges, with blur B = 1-32 min arc, and vertical disparity 0-8.B, shown for 200 ms. In the main experiment, observers reported whether they saw one central edge, one offset edge, or two edges. We argue that the relation between these three response categories and the three perceptual states (fusion, suppression, diplopia) is indirect and likely to be distorted by positional noise and criterion effects, and so we developed a descriptive, probabilistic model to estimate both the perceptual states and the noise/criterion parameters from the data.Results(1) Using simulated data, we validated the model-based method by showing that it recovered fairly accurately the disparity ranges for fusion and suppression, (2) The disparity range for fusion (Panum's limit) increased greatly with blur, in line with previous studies. The disparity range for suppression was similar to the fusion limit at large blurs, but two or three times the fusion limit at small blurs. This meant that diplopia was much more prevalent at larger blurs, (3) Diplopia was much more frequent when the two edges had opposite contrast polarity. A formal comparison of models indicated that fusion occurs for same, but not opposite, polarities. Probability of suppression was greater for unequal contrasts, and it was always the lower-contrast edge that was suppressed.ConclusionsOur model-based data analysis offers a useful tool for probing binocular fusion and suppression psychophysically. The disparity range for fusion increased with edge blur but fell short of complete scale-invariance. The disparity range for suppression also increased with blur but was not close to scale-invariance. Single vision occurs through fusion, but also beyond the fusion range, through suppression. Thus suppression can serve as a mechanism for extending single vision to larger disparities, but mainly for sharper edges where the fusion range is small (5-10 min arc). For large blurs the fusion range is so much larger that no such extension may be needed.

Project description:SIGNIFICANCE:Midday fogging of scleral contact lenses requires frequent lens removal and reapplication for a large portion of lens wearers. Using a lens filling solution that mimics the composition of tears is hypothesized to have an impact on the production of material trapped under a scleral lens. PURPOSE:The purposes of this open-label study were to assess the safety of a scleral lens filling solution, which closely approximates the ionic concentration and pH of human tears, and to assess signs and symptoms of midday fogging with this formulation and with subjects' habitual sodium chloride solutions. METHODS:Existing scleral lens wearers with midday fogging (N = 22) were examined and completed surveys of symptoms. Subjects filled the concavity of their current lenses with test solution and were assessed immediately and approximately 4 hours later for safety monitoring. Test solution was dispensed and used for 5 to 9 days when subjects were reexamined and repeated the surveys. Biomicroscopy and anterior optical coherence tomography images were used to assess midday fogging objectively. RESULTS:The median (interquartile range) Ocular Surface Disease Index score decreased from 27.1 (21.7) U when using habitual filling solution to 9.1 (20.1) U when using the test solution (P = .006). Current Symptoms Survey findings with the test solution compared with habitual solution resulted in statistically significant decreases in burning/stinging (P = .04), grittiness/foreign body sensation (P = .01), dryness (P = .002), blurry/fluctuating vision (P = .002), and overall pain/discomfort (P = .006). Objective assessment of corneal staining and fogging revealed decreases that were not statistically significant in this small sample size. CONCLUSIONS:This study establishes the safety and subject tolerance of a scleral lens filling solution that mimics the ionic composition of human tears. Significant improvements in subjective ratings, although likely biased in this unmasked trial, suggest that further studies of the effectiveness of this solution in reducing midday fogging are warranted.

Project description:Purpose:To assess the efficacy and safety of a novel ophthalmic viscosurgical device-free (OVD-free) method for posterior chamber phakic intraocular lens (PIOL) implantation in myopic eyes. Methods:In this retrospective cohort study, the medical records of myopic eyes that underwent PIOL (Implantable Collamer Lens, ICL) implantation for myopia correction at the Eye Hospital of Wenzhou Medical University between May 2015 and March 2017 were reviewed. A total of 49 eyes with complete data that met follow up requirements (2?h, 1?day, 1?week, 3?months postoperatively) were recruited. Based on the surgical techniques used, the eyes were divided into the OVD-free method group and the standard method group. The clinical data, including intraocular pressure (IOP), corrected distance visual acuity (CDVA) and spherical equivalent (SE), at each follow-up were collected for comparison. Endothelial cell loss and complications were also investigated. Results:Twenty-one eyes received the standard method, and 28 eyes received the OVD-free method. A rise in IOP >?22?mmHg at 2?h was noted in 14 eyes (66.7%) in the standard group and none (0%) in the OVD-free group (p?<?0.001). The rise in IOP from baseline was significantly higher at 2?h in the standard group (10.5?±?5.2?mmHg vs. 2.2?±?3.3?mmHg, difference: 8.3, 95% CI 5.8 to 10.8; p <?0.001). There was a significant difference in the time course of LogMAR CDVA changes between the two groups (p?=?0.047). The LogMAR CDVA was significantly better in the OVD-free method group compared to the standard group at 1?day (-?0.076, 95% CI -?0.134 to -?0.018; p?=?0.012), 1?week (-?0.071, 95% CI -?0.135 to -?0.007; p?=?0.03), but not at 3?months (-?0.046, 95% CI -?0.107 to 0.015; p?=?0.134). There was no significant difference in the time course of SE changes between the two groups (p?=?0.471; p?=?0.705). In the OVD-free group, mean endothelial cell loss was 4.6% at 3?months (2522?±?281 vs. 2407?±?226 cells/mm2, difference: -115, 95% CI -?295 to 65; p?=?0.187). No complications were reported in both groups except for the early IOP elevation in the standard group during the observation period. Conclusions:The OVD-free method is safe and efficient for ICL implantation. It can be a safer method of ICL implantation compared to the standard method in that it completely eliminates ophthalmic viscoelastic devices-related complications without causing additional complications.

Dataset Information

The scotogenic contact lens: a novel device for treating binocular diplopia.

Publications

The scotogenic contact lens: a novel device for treating binocular diplopia.

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