169,734 research outputs found
Correlazione tra la morfometria della papilla ottica e difetti dello strato delle fibre nervose retiniche (RNFL) nel glaucoma cronico semplice
No full textThe IOL-Vip System : a double intraocular lens implant for visual rehabilitation of patients with macular disease
No full textPURPOSE: To investigate the efficacy of a new surgical and rehabilitative procedure designed to improve vision in patients with central scotoma due to macular diseases. DESIGN: Case series of 40 consecutive surgical and rehabilitative procedures. PARTICIPANTS: Forty eyes of 35 consecutive patients with a stable central scotoma due to macular disease underwent phacoemulsification cataract surgery with the implant of the IOL-Vip System. METHODS: The IOL-Vip System consists of a biconcave high minus-power intraocular lens (IOL) in the capsular bag and a biconvex high plus-power IOL in the anterior chamber, reproducing an intraocular Galilean telescope with x1.3 magnification for distance. Selection of the candidate patients was carried out by means of a low-vision diagnostic and rehabilitative program (IOL-Vip software) that evaluates the residual visual function of patients and prognosis for visual improvement based on simulation of the postoperative condition. The software also designs the rehabilitation strategies based on preoperative and postoperative training of the preferred retinal locus. MAIN OUTCOME MEASURES: Best-corrected visual acuity (BCVA), evaluated by means of the Early Treatment Diabetic Retinopathy Study charts and procedure; reading magnification; and reading distance. RESULTS: All patients showed an improvement of visual acuity (VA) due to the surgical and rehabilitative procedure, confirming or exceeding the preoperative expected results. Mean postoperative BCVA was 0.77 (logarithm of the minimum angle of resolution), compared with 1.28 preoperatively. The mean postoperative best reading magnification gain was x6.2, and the mean postoperative reading distance gain was 7.66 cm. No cases of intraoperative or postoperative complications were detected, and the implant was subjectively well tolerated in both monocular and binocular procedures. CONCLUSION: In this pilot study, the IOL-Vip System was shown to be effective and apparently well tolerated in improving the vision of patients with macular disease. Best-corrected VA, reading magnification, and reading distance improved in all cases of this low-vision patient serie
Correlation between the progression of optic disc and visual field changes in glaucoma
No full textVisual field test and optic disc evaluation are the standard examination techniques used to detect the onset and progression of glaucoma. This explorative study was performed to assess the temporal correlation between visual field and optic disc changes in eyes with ocular hypertension and well-established glaucoma. Eighty-six hypertensive and 16 glaucomatous eyes were followed up for a period of up to 9 years (average 4.4 yrs) using kinetic and computerized static perimetry and optic disc manual morphometry. Perimetric changes were based on a series of strict criteria and optic disc changes were based as a reduction in the baseline rim area/disc area ratio (R/D) measurement exceeding the 99% confidence interval for intraobserver reproducibility (7.7%). Optic disc changes were found prior to visual field changes in four hypertensive eyes, whereas visual field changes were found prior to disc changes in six glaucomatous eyes (p = 0.042). The results of our explorative study suggest that quantitative optic disc analysis may be more sensitive than visual field examination in detecting early glaucomatous changes, whereas visual field examination may be more sensitive than quantitative optic disc analysis in detecting glaucomatous progressions in eyes with well established glaucoma
Sensitivity and specificity of visual field indexes and optic disc morphometry in the assessment of glaucomatous RNFL defects
No full textReading performance in patients with retinitis pigmentosa: a study using the MNREAD charts
No full textPURPOSE. To evaluate the relationship between reading performance and severity of disease in patients with retinitis pigmentosa (RP), assessed with routine clinical psychophysical visual tests.
METHODS. Seventy-six consecutive patients with RP (145 eyes), with reading acuity of at least 1.6 logMAR (logarithm of the minimum angle of resolution) in at least one eye, were examined. Each patient underwent a complete ophthalmic evaluation, including visual acuity (Early Treatment Diabetic Retinopathy Study [ETDRS] charts), contrast sensitivity (Pelli-Robson charts), visual field perimetry (Humphrey central 30-2 full-threshold program; Carl Zeiss Meditec, Dublin, CA), and a test of reading acuity, critical print size, and maximum reading speed (Minnesota Reading charts [MNREAD]).
RESULTS. Reading acuity was 1.0 logMAR or more in the better eye of all but six (92%) patients. Maximum reading speed was better than 100 words per minute in the better eye of 59 (78%) subjects. Moderate to severe reading impairment, defined as reading acuity of 0.4 logMAR or worse, was observed in the better eye of 47 (62%) patients. EDTRS visual acuity of 0.3 logMAR (20/40) or worse was 89% sensitive and 66% specific when used as a criterion to define reading impairment. Contrast sensitivity and visual acuity correlated significantly with all three reading components, whereas mean light sensitivity in the central visual field (6°) demonstrated a higher correlation with maximum reading speed. The number of years elapsed since the diagnosis of RP was a strong negative predictor of reading performance when clinical visual tests were taken into account, whereas a better reading ability characterized the patients with RP who had a higher level of education. A reduced reading speed with larger print size was found in 30 eyes (21%). This correlated with central light sensitivity, as it was more common among eyes with a mean sensitivity of <10 dB.
CONCLUSIONS. The reading performance of most patients with RP is only moderately impaired. It correlates with contrast sensitivity, visual acuity, and visual field. It should be assessed in all cases, as disability can ensue, even when visual acuity is preserved. In patients with RP with poor reading performance, there is little potential for high-magnification devices because visual field constriction affects the reading rate
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Choroidal Thickness Analysis in Patients with Usher Syndrome Type 2 Using EDI OCT
No full textTo portray Usher Syndrome type 2, analyzing choroidal thickness and comparing data reported in published literature on RP and healthy subjects. Methods. 20 eyes of 10 patients with clinical signs and genetic diagnosis of Usher Syndrome type 2. Each patient underwent a complete ophthalmologic examination including Best Corrected Visual Acuity (BCVA), intraocular pressure (IOP), axial length (AL), automated visual field (VF), and EDI OCT. Both retinal and choroidal measures were measured. Statistical analysis was performed to correlate choroidal thickness with age, BCVA, IOP, AL, VF, and RT. Comparison with data about healthy people and nonsyndromic RP patients was performed. Results. Mean subfoveal choroidal thickness (SFCT) was 248.21±79.88 microns. SFCT was statistically significant correlated with age (correlation coefficient −0.7248179, p<0.01). No statistically significant correlation was found between SFCT and BCVA, IOP, AL, VF, and RT. SFCT was reduced if compared to healthy subjects (p<0.01). No difference was found when compared to choroidal thickness from nonsyndromic RP patients (p=0.2138). Conclusions. Our study demonstrated in vivo choroidal thickness reduction in patients with Usher Syndrome type 2. These data are important for the comprehension of mechanisms of disease and for the evaluation of therapeutic approaches
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