In a low-cost laboratory setup, we compared visual acuity (VA) for stimuli rendered with Zernike aberrations to an equivalent optical dioptric defocus in emmetropic individuals using a relatively short observing distance of 60 cm. The equivalent spherical refractive error of + 1, + 2 or + 4 D, was applied in the rendering of Landolt Rings. Separately, the refractive error was introduced dioptrically in: (1) unchanged Landolt Rings with an added external lens (+ 1, + 2 or + 4 D) at the subject's eye; (2) same as (1) but with an added accommodation and a vertex distance adjustment. To compare all three approaches, we examined VA in 10 healthy men. Stimuli were observed on a PC CRT screen. For all three levels of refractive error, the pairwise comparison did not show a statistically significant difference between digital blur and accommodation-plus-vertex-distance-adjusted dioptric blur (p < 0.204). The best agreement, determined by Bland-Altman analysis, was measured for + 4 D and was in line with test-retest limits for examination in the clinical population. Our results show that even for a near observing distance, it is possible to use digitally rendered defocus to replicate dioptric blur without a significant change in VA in emmetropic subjects.
- MeSH
- Accommodation, Ocular * MeSH
- Adult MeSH
- Emmetropia * MeSH
- Middle Aged MeSH
- Humans MeSH
- Refractive Errors physiopathology MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Publication type
- Journal Article MeSH
- Clinical Trial MeSH
- Research Support, Non-U.S. Gov't MeSH
- Comparative Study MeSH
OBJECTIVE: Methamphetamine (MAP) is an indirect dopamine agonist that can temporarily increase cognitive performance. However, its long-term abuse may cause dopamine depletion and consequent cognitive and attentional impairment. The worsening of visual functions in Parkinson's disease and their improvement after levodopa administration implicates the role of dopamine in the physiology of vision. This provides the rationale for the investigation of visual functions in abstaining MAP abusers. METHODS: We investigated changes in visually evoked potentials (VEPs) to pattern-reversal and motion-onset stimuli. Such changes serve as indices of visual information processing in the primary and associative areas in a group of recently abstaining MAP abusers (5 females, 18 males, MAP abuse 5.3 +/- 2.8 years) and in 23 age- and gender-paired controls. RESULTS: We did not find differences between the groups in visual acuity. In the group of MAP abusers we observed an attenuation of the early responses around 80 ms and a prolongation of the P1 peak latency after the reversal of high spatial frequency checkerboards (10 and 20 arcmin checks). Furthermore, an attenuation of the latter positive response (170-250 ms) was observed among all the stimuli in parieto-frontal derivations for the MAP abusers. CONCLUSIONS: This is the first report suggesting a slowing and attenuation of VEP responses during visual processing in abstaining methamphetamine abusers.
- MeSH
- Adult MeSH
- Humans MeSH
- Methamphetamine adverse effects MeSH
- Young Adult MeSH
- Amphetamine-Related Disorders physiopathology MeSH
- Motion Perception physiology MeSH
- Visual Pathways physiopathology MeSH
- Evoked Potentials, Visual physiology MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Methamphetamine MeSH
PURPOSE: The aim of this neurophysiological study was to monitor changes in the visual and cognitive function of HIV-infected patients treated with combination antiretroviral therapy. METHODS: Eleven adult Czech HIV+ patients, with a mean age of 35 years and CD4 cell count ≥ 230 × 106 cells/L of blood at the time of enrollment, underwent four to six examinations over the course of 2.5 years to evaluate pattern-reversal and motion-onset visual evoked potentials (P-VEPs and M-VEPs), visually driven oddball event-related potentials (ERPs) and Montreal Cognitive Assessments. In addition to evaluating the intraindividual change in the observed parameters, we also compared patient data to data from eleven age- and gender-matched controls. RESULTS: We did not find any significant differences in P-VEPs between the patients and controls or in the paired comparison of the first and last visit. The only significant finding for P-VEPs was a linear trend in prolongation of the 20' P-VEP P100 peak time. In M-VEPs, we found a significant intergroup difference in the N160 peak time recorded during the first visit for peripheral M-VEPs only. During the last visit, all N160 peak times for patients differed significantly from those of the control group. The only intervisit difference close to the level of significance was for peripheral M-VEPs, which confirmed the trend analysis. No significant differences between patients and controls were found in the ERPs, but the P300 peak time showed a significant difference between the first and last visits, as confirmed by the trend. Patient reaction time was not significantly delayed at the first visit; however, it was prolonged with time, as confirmed by the trend. CONCLUSION: Our aim was to evaluate whether antiretroviral treatment in HIV+ patients is sufficient to preserve brain visual function. The optic nerve and primary visual cortex function tested by the P-VEPs seem to be preserved. The prolongation of the M-VEPs suggests an individually detectable decline in CNS function, but these changes did not show a progression during the follow-up. From a longitudinal perspective, the trends in peak time prolongation of the 20' P-VEP, peripheral M-VEP, ERP and reaction time suggest a faster decline than that caused by aging in healthy populations, as previously described in a cross-sectional study.
- Keywords
- Event-related potentials (ERPs), Human immunodeficiency virus (HIV), Motion-onset VEP, Pattern-reversal VEP, Visual evoked potentials (VEPs),
- MeSH
- Anti-Retroviral Agents therapeutic use MeSH
- Adult MeSH
- Electroretinography MeSH
- Evoked Potentials physiology MeSH
- HIV Infections drug therapy physiopathology MeSH
- Cognition physiology MeSH
- Middle Aged MeSH
- Humans MeSH
- Longitudinal Studies MeSH
- Young Adult MeSH
- CD4 Lymphocyte Count MeSH
- Cross-Sectional Studies MeSH
- Reaction Time physiology MeSH
- Motion Perception physiology MeSH
- Visual Acuity physiology MeSH
- Evoked Potentials, Visual physiology MeSH
- Visual Cortex physiology MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Anti-Retroviral Agents MeSH
PURPOSE: To analyze and compare visual acuity, refractive outcomes and higher-order aberrations after standard and wavefront-guided Femto-LASIK at 1, 3, and 12 months postoperatively. METHODS: Study of 95 consecutive eyes of myopic patients (-0.5 to -7.0 D), who underwent Femto-LASIK with standard ablation profile (STA) (49 eyes) or wavefront-guided ablation (WFG) (46 eyes) using femtosecond laser LDV Ziemer and excimer laser MEL 80 Zeiss with iris registration. Primary outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction and higher-order ocular aberrations (HOAs). HOAs were measured with Hartmann-Shack wavefront aberrometer WASCA, HOAs analyzed at 6 mm pupil, assessed total HOAs root mean square (RMS HOAs) and individual Zernike coefficients. RESULTS: Preoperatively, there were no significant differences between STA and WFG groups in UDVA, CDVA, manifest refraction or HOAs. As compared with preoperative values, spherical aberration Z(4,0) increased by 0.24 µm in both groups and it is the main increasing factor of RMS HOAs (0.05 µm in STA group and 0.08 µm in WFG group). Safety and efficacy index is 1.0 in both ablation profiles. Postoperatively, median UDVA and CDVA achieved 1.2. No patient lost line of CDVA at 12 month postoperatively. All patients were within ± 0,5 D of emmetropia at 12 months. Significant differences were not found between STA and WFG in UDVA, CDVA, manifest refraction or HOAs at 1, 3 and 12 month. CONCLUSIONS: Both wavefront-guided and standard Femto-LASIK with LDV and MEL 80 platform have shown very good efficacy and safety. Myopic Femto-LASIK only slightly increases RMS HOAs, especially by induction of spherical aberration. Both methods have equivalent postoperative aberration score one year postoperatively.Key words: femtosecond LASIK, higher-order aberrations, wavefront-guided, visual accuity.
- MeSH
- Time Factors MeSH
- Keratomileusis, Laser In Situ methods MeSH
- Lasers, Excimer therapeutic use MeSH
- Humans MeSH
- Myopia physiopathology surgery MeSH
- Follow-Up Studies MeSH
- Postoperative Complications * MeSH
- Refraction, Ocular MeSH
- Corneal Wavefront Aberration diagnosis etiology physiopathology MeSH
- Treatment Outcome MeSH
- Visual Acuity * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Comparative Study MeSH
INTRODUCTION: Low visual aids (LVAs) are the simplest and the most economic method of reducing the consequences of visual impairment (VI). We evaluate prescribing of LVAs in order to improve the quality of life of visually impaired children. MATERIAL AND METHODS: We retrospectively reviewed the notes of 113 patients (pts.) with VI (visual acuity (VA) 6/18 or worse or with visual field defects) who attended the Low Vision Clinic, F.D. Roosevelt Hospital in Banska Bystrica, between Jan 2000 - Dec 2005. There were 61 boys and 52 girls with ages ranging from < 1 year to < 19 years (mean age 9.4 years, median 9 years). RESULTS: Of the 113 notes reviewed, only 109 of patients were cooperative in having their VA formally tested. Blindness (VA worse than 3/60) occurred in 31 pts. (28.4%) and Low vision (VA worse than 6/18 or equal to 3/60) in 67 (61.5%). Of the remaining 11 patients, 4 had gross field defects (and good VA), (indicating that the total number with Low vision was 71 (65%). The other 7 patients had either developmental delay or were too young to perform a formal visual field test. Blindness was caused by perinatal factors in 52% of cases, prenatal factors in 45% and postnatal factors in 3%. Low vision was caused in 74.6% of cases by prenatal factors. The causes of blindness according to the affected anatomical site were: optic nerve disease in 12 (39%), cerebral visual impairment (CVI) in 8 (26%), and retinal disease in 6 (20%). Low vision was caused by retinal disease in 23 (34.3%), lens pathology in 11 (16.5%) and CVI in 10(14.9%). 171 LVAs were prescribed to 74 patients (65%): 76 (44.4%) were magnifiers, 21 (12.3%) were hyperoculars or high adds, 65 (38%) were telescopes and 9 (5.5%) telescope extensions. An average of 1.5 devices was prescribed for each patient. Every patient who was prescribed an LVA had subjective and objective improvement of their visual function and functional vision. CONCLUSION: Blindness occurred in almost one third of our patients which agrees with the worldwide accepted estimate. The LVA are improving the quality of life of visually impaired children. The prescribing of LVA depends on the individual: it is not possible to anticipate the optical power of the LVA that a patient will need simply from looking at their diagnosis and measuring their VA because there are so many different requirements depending on their age and visual demands.
- MeSH
- Lenses * MeSH
- Child MeSH
- Infant MeSH
- Humans MeSH
- Adolescent MeSH
- Young Adult MeSH
- Optical Devices MeSH
- Child, Preschool MeSH
- Blindness * etiology therapy MeSH
- Vision, Low etiology therapy MeSH
- Visual Acuity MeSH
- Check Tag
- Child MeSH
- Infant MeSH
- Humans MeSH
- Adolescent MeSH
- Young Adult MeSH
- Male MeSH
- Child, Preschool MeSH
- Female MeSH
- Publication type
- English Abstract MeSH
- Journal Article MeSH
OBJECTIVE: To present clinical results of patients with myopia up to -6 dioptres (D) after photorefractive keratectomy (PRK) and evaluate their stability during a 4-year period. MATERIAL AND METHODS: The authors evaluated retrospectively the refraction before and after surgery in patients with myopia up to -6 D during the period from September 1997 till December 2000. The group comprised a total of 847 eyes. The mean spherical refraction during the whole follow up period was before surgery -3.61 +/- 1.17 D, the mean astigmatism was -0.65 +/- 0.63 D, non-corrected visual acuity (UCVA) 0.09 +/- 0.09, the visual acuity with optimal correction (BCVA) 1.21 +/- 0.30. RESULTS: One year after PRK we achieved in our group a mean spherical refraction of -0.17 +/- 0.74 D, a mean astigmatism of -0.61 +/- 0.43 D, UCVA 0.92 +/- 0.25, BCVA 1.02 +/- 0.19. CONCLUSION: Photorefractive keratectomy is an effective and safe method for correction of myopia up to -6 D. The results as regards refraction were comparable with other departments and did not differ much during individual years. Stabilization occurs 3-6 months after the operation.
PURPOSE: In this prospective observational comparative case series, we aimed to study the peripapillary capillary network with spectral-domain optical coherence tomography angiography (OCT-A) in Leber hereditary optic neuropathy (LHON). METHODS: Twelve eyes of six individuals, of these three males (five eyes) after clinical onset of visual impairment were imaged by OCT-A with scans centred on optic discs. Control group consisted of 6 eyes with no visual impairment. RESULTS: The three affected individuals lost vision 6 years (at age 22 years), 2 years and 3 months (at age 26 years) and 1 year and 2 months (at age 30 years) prior to OCT-A examination. All five affected eyes had alterations in density of the radial peripapillary microvascular network at the level of retinal nerve fibre layer, including an eye of a patient treated with idebenone that underwent almost full recovery (best corrected visual acuity 0.87). Interestingly, the other eye showed normal ocular findings 14 months after onset. Results of OCT-A examination in this eye were unfortunately inconclusive due to a delineation error. At the level of the ganglion cell layer differences could be also noted, but only in two severely affected individuals. There were no differences between unaffected mutation carriers and control eyes. CONCLUSION: Optical coherence tomography angiography scans confirmed that the peripapillary microvascular network is highly abnormal in eyes manifesting visual impairment due to LHON. These findings support the hypothesis that microangiopathy contributes to the development of vision loss in this mitochondrial disorder.
- Keywords
- Leber hereditary optic neuropathy, microangiopathy, mitochondrial, optical coherence tomography angiography, peripapillary microcirculation,
- MeSH
- Optic Disk blood supply diagnostic imaging MeSH
- Child MeSH
- Adult MeSH
- Fluorescein Angiography methods MeSH
- Fundus Oculi MeSH
- Optic Atrophy, Hereditary, Leber diagnosis physiopathology MeSH
- Humans MeSH
- Microvessels diagnostic imaging MeSH
- Microcirculation physiology MeSH
- Adolescent MeSH
- Young Adult MeSH
- Nerve Fibers pathology MeSH
- Tomography, Optical Coherence methods MeSH
- Prospective Studies MeSH
- Retinal Vessels diagnostic imaging physiopathology MeSH
- Retinal Ganglion Cells pathology MeSH
- Visual Acuity * MeSH
- Visual Fields MeSH
- Check Tag
- Child MeSH
- Adult MeSH
- Humans MeSH
- Adolescent MeSH
- Young Adult MeSH
- Male MeSH
- Publication type
- Journal Article MeSH
- Observational Study MeSH
- Comparative Study MeSH
INTRODUCTION: The study describes cases of patients screened for worse vision and headaches. We are trying to point out we can measure minus diopters even at latent hypemetropes. These patients come to a doctor for a variety of problems that may be caused by inadequate correction of ametropia. It is necessary to know about this possibility, and rather perform cycloplegia in sporadic cases. METHODS: Patients were measured at autorefractometer without mydriasis, and then after using UNITROPIC 1% or CYCLOGYL 1%. Both of these substances induce cycloplegia. Visual acuity with the best correction was tested with and without cycloplegia. RESULTS: After cycloplegia, a significant change in both objective and subjective refraction was detected in most of the selected patients. This change was within the meaning of a shift to hyperopia. Subsequent adjustment correction led to resolving of problems. CONCLUSION: The work should highlight the necessity of an individual approach of prescription of the best correction. Not always an autorefractometer gives correct information, the real-needed correction is completely different in some cases.
- MeSH
- Headache etiology therapy MeSH
- Eyeglasses MeSH
- Adult MeSH
- Hyperopia complications diagnosis therapy MeSH
- Humans MeSH
- Young Adult MeSH
- Myopia complications diagnosis therapy MeSH
- Visual Acuity * MeSH
- Vision Tests MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
GOAL: To make the reader familiar with the term evidence based medicine (EBM), to explain the principle of cost-effectiveness analysis (price-profit), and to show its usefulness to compare the effectiveness of different medical procedures. METHOD: Based on few examples, in this article the relevance and calculation of important parameters of cost-effectiveness analysis (CE), as utility value (UV), quality adjusted life years (QALY) is explained. In addition, calculation of UV and QALY for the cataract surgery, including its complications, is provided. RESULTS: According to this method, laser photocoagulation and cryocoagulation of the early stages of retinopathy of prematurity, treatment of amblyopia, cataract surgery of one or both eyes, from the vitreoretinal procedures the early vitrectomy in cases of hemophtalmus in proliferative diabetic retinopathy or grid laser photocoagulation in diabetic macular edema or worsening of the visual acuity due to the branch retinal vein occlusion belong to highly effective procedures. On the other hand, to the procedures with low cost effectiveness belongs the treating of the central retinal artery occlusion with anterior chamber paracentesis, as well as with CO2 inhalation, or photodynamic therapy in choroidal neovascularization in age-related macular degeneration with visual acuity of the better eye 20/200. CONCLUSION: Cost-effectiveness analysis is a new perspective method evaluating successfulness of medical procedure comparing the final effect with the financial costs. In evaluation of effectiveness of individual procedures, three main aspects are considered: subjective feeling of influence of the disease on the patient's life, objective results of clinical examination and financial costs of the procedure. According to this method, the cataract surgery, as well as procedures in the pediatric ophthalmology belong to the most effective surgical methods.
- MeSH
- Cost-Benefit Analysis MeSH
- Cataract Extraction economics MeSH
- Quality-Adjusted Life Years * MeSH
- Humans MeSH
- Evidence-Based Medicine * MeSH
- Ophthalmologic Surgical Procedures * economics MeSH
- Visual Acuity MeSH
- Check Tag
- Humans MeSH
- Publication type
- English Abstract MeSH
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
PURPOSE: To analyze patients with optic disc drusen (ODD), with emphasis on modern diagnostics. MATERIALS AND METHODS: Research of the literature was conducted, together with a retrospective statistical analysis of patients with ODD. The group included individuals with ODD diagnosed using at least one of the following (ultrasound - USG, optical coherence tomography - OCT, fundus autofluorescence - FAF). RESULTS: The group consisted of 12 patients (23 eyes), 7 women and 5 men. The mean age was 25 years. The mean observation period was 73 months. In total, 11 patients (22 eyes) had a bilateral finding and 1 patient (1 eye) had a unilateral finding. The mean age was 25 years. Buried drusen were confirmed in 69.6% of cases (8 patients, 16 eyes), superficial drusen were confirmed in 30.4% of cases (4 patients, 7 eyes). Mean best corrected visual acuity (BCVA) and mean intraocular pressure were stable over time (BCVA p = 0.236, IOP p = 0.855). The aforementioned diagnostic methods proved to be equally effective (p = 0.768). In 11 patients (21 eyes) a depression of the retinal nerve fiber layer (RNFL) was recorded. We found a statistically significant decrease of the RNFL over time in reference to the normative database in the superior temporal (p = 0.015), temporal (p = 0.026) and nasal segments (p = 0.011). After separation of superficial and buried drusen the same significant change was found in nasal segment in superficial drusen (p = 0,031). We found no statistically significant difference over time between superficial and buried drusen (p = 0.109-0.999 for individual segments). CONCLUSION: ODD are common and visual functions remain stable. Their presence can be confirmed using modern paraclinical methods.
- Keywords
- Fundus autofluorescence, Optic disc drusen, optical coherence tomography, ultrasound,
- MeSH
- Adult MeSH
- Optic Disk Drusen * diagnostic imaging MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Tomography, Optical Coherence * MeSH
- Retrospective Studies MeSH
- Ultrasonography MeSH
- Visual Acuity MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
