1/19. Acquired unilateral visual loss attributed to an accommodative spasm.BACKGROUND: Accommodative spasm (AS) has been reported to be a rare cause of an acquired unilateral visual loss. We describe a unique case of acquired visual loss due to an apparent unilateral AS triggered by occlusion of the contralateral eye. Clinical examination and photorefraction techniques were performed during the acute phase of the disorder and in the follow-up evaluations. CASE REPORT: An otherwise healthy 27-year-old woman presented with a 2-month decrease of vision in her left eye. Unaided visual acuity in the right eye was 20/20 and in the left eye was finger counting. Orthophoria existed at distance and near. The decrease in vision in the left eye was attributed to an apparent unilateral AS of 5 D, which occurred only when the right eye was occluded. Under the occluder, the right eye also manifested an AS. With the left eye occluded or with binocular viewing, the right eye and left eye accommodated normally. With a 5 D convex lens before the right eye, the visual acuity in the left eye was 20/20. Refractive error with cycloplegia revealed low hyperopia in each eye. CONCLUSION: AS can be the cause of acquired unilateral visual loss. To our knowledge, this is the first documented report of an apparent unilateral AS triggered by occlusion of the contralateral eye.- - - - - - - - - - ranking = 1keywords = error (Clic here for more details about this article) |
2/19. Effect of high-altitude exposure on myopic laser in situ keratomileusis.PURPOSE: To study the effect of high-altitude exposure on visual acuity after myopic laser in situ keratomileusis (LASIK). SETTING: Aconcagua, Mendoza, argentina. methods: In the early postoperative period after uneventful myopic LASIK, 2 physicians prospectively assessed their visual acuity during an ascent of Aconcagua (22841 feet). The distance uncorrected visual acuity (UCVA) and peripheral oxygenation were measured at approximately every 2000 feet of altitude. RESULTS: Both climbers developed a moderate loss of distance UCVA but described normal near and pinhole acuity consistent with a myopic shift. The distance UCVA diminished to 20/100 in the right eye and 20/125 in the left eye of Climber A and to 20/160 and 20/30, respectively, of Climber B. The vision loss worsened with increased altitude, duration of exposure, and decreased peripheral oxygenation. One week after the climb, the manifest refraction demonstrated a small myopic shift in both eyes of Climber A; these subsequently resolved. CONCLUSIONS: Two climbers, 8 and 14 weeks after myopic LASIK, experienced vision loss consistent with a temporary myopic shift in the refractive error with ascent to high altitude. Climbers who have LASIK, particularly those in the early postoperative period, should be prepared for visual acuity fluctuations with high-altitude exposure.- - - - - - - - - - ranking = 515.65506617627keywords = refractive error, error (Clic here for more details about this article) |
3/19. Systematic underablation in laser in situ keratomileusis: ablation pattern identified by advanced topographical analysis.Topographical analysis based on the differential geometry of surfaces-curvature topography-was developed and applied to a patient after laser in situ keratomileusis. The patient had a minimal residual refractive error and normal best corrected visual acuity but had multiple visual aberrations, including ghosting and glare, unless the pupils were maximally constricted. The corneal loci responsible for the aberrations were difficult or impossible to identify on axial topographies but were readily identified with curvature topography. The patient's ablations appeared to be miniature versions of the intended ablation profiles, with small areas of emmetropic central cornea surrounded by annuli of rapidly increasing keratometric power; that is, systematic underablation. This may explain why some patients have visual aberrations with pupil diameters smaller than the programmed optical zones.- - - - - - - - - - ranking = 515.65506617627keywords = refractive error, error (Clic here for more details about this article) |
4/19. Unexplained visual loss.Dominant optic atrophy is the most common heredodegenerative optic neuropathy. Typically, patients present with slowly progressive, bilaterally decreased central visual acuity. Subtle central or cecocentral visual field defect and normal peripheral isopters are demonstrated with perimetry. A defect in blue-yellow discrimination (tritan error axis) is the most common type of dyschromatopsia, however protan and deutan axes may be superimposed. A characteristic optic disk appearance includes temporal disk pallor with excavation. An autosomal dominant inheritance pattern can often be elicited from the family history.- - - - - - - - - - ranking = 1keywords = error (Clic here for more details about this article) |
5/19. Wavefront-guided treatment of abnormal eyes using the LADARVision platform.PURPOSE: To evaluate the clinical results of Alcon LADARVision4000 wavefront-guided customized treatment of eyes with myopia and/or astigmatism, and clinically significant visual symptoms related to the presence of higher order aberrations. methods: Seven consecutive abnormal eyes from seven patients underwent wavefront-guided CustomCornea (1 PRK, 6 enhancements after previous LASIK) to correct low and higher order aberrations, using the Alcon LADARVision4000 platform. Eyes were examined at 1 to 3 months after treatment; the longest follow-up examination was used for analysis. Uncorrected and best spectacle-corrected visual acuity, manifest refractive spherical equivalent error, and subjective visual symptoms were measured, as well as wavefront measurement of higher order aberrations. RESULTS: All seven eyes had an improvement in UCVA. One eye gained 2 lines of BSCVA, four eyes gained 1 line, and no eye lost any lines. Manifest refractive spherical equivalent error was slightly hyperopic in all eyes ( 0.12 to 1.50 D). All eyes showed a reduction in pre-existing higher order aberrations, ranging between 1% and 48%. Spherical aberration was reduced most (mean 38% reduction), coma was reduced by a mean 14%, and all other terms were reduced by a mean 17% compared to preoperative values. Subjectively, all patients noticed a reduction in their pre-existing visual symptoms and reported visual performance comparable to their fellow asymptomatic eye. overall, the treatment was considered very satisfactory by patients in terms of visual quality gain. CONCLUSION: Wavefront-guided custom ablation with Alcon's LADARVision4000 was effective in reducing higher order aberrations and related visual symptoms in this preliminary small series. Longer follow-up on more eyes is necessary to assess the accuracy of the algorithm in the correction of defocus, which resulted in a slight overcorrection in this study.- - - - - - - - - - ranking = 2keywords = error (Clic here for more details about this article) |
6/19. Complete bilateral vitreous detachment after LASIK retreatment.We describe a case of a 47-year-old woman who underwent bilateral laser in situ keratomileusis (LASIK) for the correction of myopia and astigmatism. Two months later a residual refractive error was present in both eyes. LASIK retreatment was decided and performed the following day. Twenty-four hours after the procedure, the patient reported myodesopsia in both eyes. Funduscopic examination revealed a complete bilateral posterior vitreous detachment confirmed by kinetic ultrasound. Visual disturbance in both eyes continued to be present after 10 months of follow-up. Sudden changes in intraocular pressure related to suction ring use might be the cause of posterior vitreous detachment in this patient.- - - - - - - - - - ranking = 515.65506617627keywords = refractive error, error (Clic here for more details about this article) |
7/19. Impact of the line of sight on toric phakic intraocular lenses for hyperopia.We present a hyperopic patient with a decentered line of sight in whom the residual refractive error after toric phakic intraocular lens (TP IOL) implantation was improved by displacement and individualized treatment. A 35-year-old woman presented with asthenopic complaints 2 months after bilateral TP IOL implantation and IOL rotation 4 weeks later. Examination revealed the line of sight to be nasally and inferiorly decentered in relation to the center of the pupil. A more nasal reenclavation of the TP IOL decreased the coma, and the uncorrected visual acuity was 20/20. We conclude that line of sight should be measured before TP IOL implantation, especially in hyperopic eyes.- - - - - - - - - - ranking = 515.65506617627keywords = refractive error, error (Clic here for more details about this article) |
8/19. The need for optometric investigation in suspected Meares-Irlen syndrome or visual stress.Meares-Irlen syndrome is characterised by symptoms of eye strain, headaches and visual perceptual distortions when viewing text. The symptoms are alleviated with individually prescribed coloured filters, such as precision tinted lenses. Meares-Irlen syndrome, and the related condition of visual stress, are likely to result from hyperexcitability of the visual cortex, which can also occur in migraine. The symptoms of Meares-Irlen syndrome and visual stress are non-specific and the condition needs to be differentially diagnosed from other optometric conditions, such as refractive error, binocular vision anomalies, and accommodative anomalies. Three case reports are described of patients who consulted the author with suspected Meares-Irlen syndrome but were found to have other causes for their symptoms: posterior sub-capsular cataract, high uncorrected astigmatism, and decompensated convergence weakness exophoria. These cases highlight the need for professional eye care for people with suspected Meares-Irlen syndrome. Although this advice is stressed in literature on the well-established MRC/Wilkins Intuitive Colorimeter system, it is not always stressed in literature about other systems. This may be a cause for concern.- - - - - - - - - - ranking = 515.65506617627keywords = refractive error, error (Clic here for more details about this article) |
9/19. Illusory conjunctions in simultanagnosia: coarse coding of visual feature location?Simultanagnosia is a disorder characterized by an inability to see more than one object at a time. We report a simultanagnosic patient (ED) with bilateral posterior infarctions who produced frequent illusory conjunctions on tasks involving form and surface features (e.g., a red T) and form alone. ED also produced "blend" errors in which features of one familiar perceptual unit appeared to migrate to another familiar perceptual unit (e.g., "RO" read as "PQ"). ED often misread scrambled letter strings as a familiar word (e.g., "hmoe" read as "home"). Finally, ED's success in reporting two letters in an array was inversely related to the distance between the letters. These findings are consistent with the hypothesis that ED's illusory reflect coarse coding of visual feature location that is ameliorated in part by top-down information from object and word recognition systems; the findings are also consistent, however, with Treisman's Feature Integration Theory. Finally, the data provide additional support for the claim that the dorsal parieto-occipital cortex is implicated in the binding of visual feature information.- - - - - - - - - - ranking = 1keywords = error (Clic here for more details about this article) |
10/19. Potential complications of ocular surgery in patients with coexistent keratoconus and fuchs' endothelial dystrophy.PURPOSE: To describe the potential complications of cataract and refractive surgery in patients with fuchs' endothelial dystrophy (FED) and keratoconus. DESIGN: Retrospective case series. PARTICIPANTS: Eight patients with FED and keratoconus in a large university group practice. methods: We reviewed the clinical and topographic findings of 8 patients (15 eyes) with FED and keratoconus. Clinical examination, corneal topography, specular microscopy were done, and sequential central corneal thickness (CCT) was obtained. Follow-up ranged from 1 month to 6 years. MAIN OUTCOME MEASURES: Findings of keratoconus and FED in preoperative evaluation. RESULTS: Five patients had concomitant cataracts; 3 had refractive errors and sought surgical correction. Cataract surgery was performed on 3 of 5 patients (5 eyes). LASIK was performed on one eye of 3 patients. Of 5 eyes that underwent cataract extraction, 4 had blurry vision after surgery. The interval between the surgical procedure and onset of symptoms ranged from 1 month to 4 years. The causes of decreased vision after cataract surgery were corneal edema and/or corneal ectasia. The CCT readings ranged from 426 to 824 microm. One of 4 symptomatic eyes underwent penetrating keratoplasty. The CCTs of 3 patients (6 eyes) who presented with refractive error ranged from 507 to 565 microm. One eye had undergone an attempted LASIK procedure resulting in a lost cap. corneal topography and specular microscopy showed the coexistence of keratoconus and FED, and the patients were advised against having LASIK surgery. CONCLUSIONS: Corneal thinning caused by keratoconus and concurrent increase in corneal thickness caused by FED may combine to normalize the corneal pachymetry readings; disease severity may be underestimated, which may lead to unexpected postoperative visual outcomes. Routine use of preoperative topography and specular microscopy may help to avert potential surgical complications.- - - - - - - - - - ranking = 1031.3101323525keywords = refractive error, error (Clic here for more details about this article) |
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