Biomedical subjects

Ori Segal

Publications and source records attributed to Ori Segal.

7 recordsLinked to original sources

PubMed2005

Ocular higher-order aberrations in eyes with supernormal vision.

PURPOSE: To quantify ocular higher-order aberrations (HOAs) in eyes with supernormal vision, that is, natural uncorrected visual acuity (UCVA) > or = 20/15, to analyze the correlation between ocular HOAs and age in these eyes, and to investigate the correlation of HOAs between right and left eyes. DESIGN: Observational case series. METHODS: Ocular HOAs were examined across a naturally dilated pupil with a diameter > or = 6.0 mm in 70 eyes of 35 subjects with > or = 20/15 UCVA (mean age 24.3 years +/- 7.7 [SD]) using the Nidek OPD scan wavefront aberrometer. Root-mean-square (RMS) values of HOA, total spherical aberration (TSA), total coma (TC), and total trefoil (TT) were analyzed. Correlation analysis was performed to assess the association between ocular HOAs and age and the correlation of HOAs between right and left eyes. RESULTS: Mean RMS values were 0.334 +/- 0.192 microm for HOA, 0.110 +/- 0.077 microm for TSA, 0.136 +/- 0.081 microm for TC, and 0.268 +/- 0.220 microm for TT. There were no significant differences in the mean values of HOA, TSA, TC, and TT between right and left eyes. The Pearson correlation coefficient between right and left eyes for TSA was 0.764 (P<.0001). No significant correlation was found between right and left eyes for HOA, TC, and TT. No significant correlation was found between each of the ocular aberrations and age. CONCLUSIONS: The amount of ocular HOAs in eyes with natural supernormal vision is not negligible, and is comparable to the reported amount of HOAs in myopic eyes.

Adolescent↗

PubMed2005

Ocular higher-order aberrations in myopia and skiascopic wavefront repeatability.

PURPOSE: To study the distribution of ocular higher-order aberrations (HOAs) in a myopic population and to assess the repeatability of HOA measurements determined by a commercially available skiascopic wavefront sensor. SETTING: Department of Ophthalmology, Assaf Harofeh Medical Center, Zerifin, Israel. METHODS: Ocular HOAs were examined 3 times across a 6.0 mm naturally dilated pupil in 61 eyes using the Optical Path Difference (OPD)-scan wavefront aberrometer. Root-mean-square (RMS) values of HOAs, total spherical aberration (TSA), total coma (TC), and total trefoil (TT) were analyzed. Correlation analysis was performed to assess the aberration symmetry between right and left eyes. The repeatability of the OPD-scan measurements was assessed by calculating Pearson r correlation coefficients between each pair of measurements and the interclass correlation coefficients between the 3 measurements of each score. RESULTS: The mean RMS values of HOAs, TSA, TC, and TT were 0.347 microm +/- 0.252 (SD), 0.120 +/- 0.174 microm, 0.165 +/- 0.168 microm, and 0.252 +/- 0.157 microm, respectively. The HOAs, TSA, TC, and TT changed slightly and not significantly with increasing refractive error (all P>.05). The RMS level of HOAs and TTR of the 3rd measurement was significantly different from the 1st and 2nd measurements (P<.05), with overall low correlation between the 3 measurements for the HOAs, TSA, TC, and TT. CONCLUSIONS: The ocular wavefront aberrations varied greatly from subject to subject. Ocular HOAs were not correlated with refractive error. The repeatability of HOAs measurements with the OPD-aberrometry was low.

Adolescent↗

PubMed2005

Reduction of conjunctival bacterial flora by povidone-iodine, ofloxacin and chlorhexidine in an outpatient setting.

PURPOSE: To compare the reduction of conjunctival bacterial flora by povidone-iodine 4%, ofloxacin 0.3%, and chlorhexidine 0.05% for endophthalmitis prophylaxis before corneal suture removal in an outpatient setting. METHODS: In each group of 25 consecutive subjects who presented for outpatient ophthalmic evaluation, one eye was treated with either povidone-iodine 4% (PI), ofloxacin 0.3% (Oflox) or chlorhexidine 0.05% (Chex). The other eye served as a control. Three minutes after treatment, cultures were taken from the inferior conjunctival sac in both eyes. Following incubation at 35 degrees for 48 hours, the numbers of colonies were counted and compared. The difference in the numbers of colonies in each pair of treated and control eyes was assessed for each drug and compared. RESULTS: The reduction in colony-forming units was highly significant for each of the three drugs tested (Wilcoxon signed-ranks test; p < 0.0001). There was no significant difference between percent reduction by the three drugs (Kruskal-Wallis test; p = 0.68). Sterile cultures following preparation by PI, Oflox and Chex were obtained in 52%, 68% and 52%, respectively. CONCLUSIONS: The regimens tested were similarly effective in reducing conjunctival commensals. They may all be considered as options for a quick prophylaxis against infection following suture removal in an outpatient setting.

Anti-Infective Agents, Local↗

PubMed2005

The effect of cataract surgery on postural control.

PURPOSE: Falls are a significant cause of morbidity in the elderly. Because decreased vision is known to be a significant risk factor for falling in this age group, we sought to examine the effect of the removal of cataract, a major cause of visual handicap, on postural stability. METHODS: Postural stability was measured in 23 patients who underwent cataract surgery, before and 1 to 4 months after surgery. Stability indices included Stability Effect, Fourier Spectrum of Postural Sway, and Synchronizations, and, based on these measurements, Falling Index, which had been shown in earlier studies to predict the risk of falling. RESULTS: Visual acuity in the surgical eye significantly improved in all patients after surgery (P < 0.01) and did not change in the fellow eye. Stability improved in most patients (19/23) and Fourier Spectrum of Postural Sway improved in the high-frequency bands (above 0.5 Hz), when viewing with the surgical eye, but not when viewing with the nonsurgical eye (P < 0.05). By Falling Index, before surgery, 12 of 23 patients were at high risk of falling, and only six were at low risk. After surgery, 16 of 23 were at low risk and only three remained at high risk (chi(2) test, P < 0.008). CONCLUSIONS: Cataract surgery significantly improves postural stability. Considering the high cost of treating fall-related injuries in the elderly, the findings may imply that cataract surgery is cost effective in this regard.

Accidental Falls↗

PubMed2003

Prediction of visual outcome after penetrating keratoplasty for pseudophakic corneal edema.

OBJECTIVE: To evaluate the ability to predict visual outcome after penetrating keratoplasty (PKP) in patients with pseudophakic corneal edema (PCE) or aphakic corneal edema (ACE) based on preoperative parameters available from the patient history and ocular examination. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: Forty-eight patients who underwent 59 PKP procedures for PCE between 1997 and 2000 by two cornea specialists. METHODS: Medical records were retrospectively analyzed for variables in the history and ocular examination before PKP and visual outcome after PKP. Variables included age, gender, presence of diabetes or cardiovascular disease, method of intraocular lens (IOL) implantation during cataract surgery, vitreous loss during cataract surgery, time between cataract and PKP surgery, and maximal visual acuity reached after cataract surgery. The predictive value of each preoperative variable on post-PKP visual outcome was assessed using both univariate and multiple regression analyses. MAIN OUTCOME MEASURES: Statistical significance for the predictive value of each preoperative variable on post-PKP visual outcome. RESULTS: Best-corrected visual acuity (BCVA) of 20/40 or better was achieved in 13 patients (27%). The strongest predictor of this outcome was implantation of a bag-fixated or sulcus-fixated IOL at the time of cataract surgery (P = 0.007; odds ratio, 15.8; 95% confidence interval, 1.2-208). Less significant variables included BCVA after cataract surgery, time between cataract surgery and PKP, and gender. CONCLUSIONS: In planning and advising patients with pseudophakic or aphakic corneal edema who are candidates for PKP, the method of IOL implantation during the cataract surgery is the single most significant predictor of visual acuity after corneal transplantation. Bag-fixated or sulcus-fixated posterior chamber IOL was associated with a better visual outcome than anterior chamber IOL, scleral-fixated posterior chamber IOL, or aphakia.

Aged↗

PubMed2003

Scleral contact lenses may help where other modalities fail.

PURPOSE: To describe the vision-correcting and therapeutic benefits of gas-permeable scleral contact lenses (GP-ScCL) in the management of irregular corneal surface disorders and ocular surface diseases. METHODS: The charts of 48 consecutive patients (66 eyes) whose management included the use of GP-ScCL were reviewed. RESULTS: The most common indication for fitting the lenses was keratoconus in patients who had to stop wearing other types of corneal lenses (44 eyes, 74.6%). Other indications included extreme corneal irregularity after penetrating keratoplasty, nonhealing corneal ulcer, postoperative dry eye syndrome following laser in situ keratomileusis (LASIK), severe exposure keratitis and acid burn. Mean follow-up was 17 months (range, 2-96). Mean wearing time of the GP-ScCL was 16.2 hours per day (range, 3-18). Visual acuity of 20/40 or better was achieved in 90.9% of keratoconus patients and in 81.8% of postkeratoplasty patients. A gain of two or more Snellen lines was observed in 94.5% of eyes treated for improving vision. Marked subjective improvement in quality of life was reported by 86% of the patients, mainly as a result of improvement in their visual function and reduction in discomfort. Five patients (seven eyes) failed to wear GP-ScCL. CONCLUSION: GP-ScCL can provide successful and safe visual and therapeutic solutions for ocular conditions when conventional contact lenses and medical treatment have failed and where surgery is undesirable or contraindicated.

Adolescent↗

PubMed2002

Correlation between reading skills and different measurements of convergence amplitude.

PURPOSE: To find correlations between convergence amplitude and reading ability, as assessed in various methods. METHODS: Convergence of 66 children aged 8-10 years was evaluated using 1) Non-accommodative target at near and distance; 2) A near computerized stereogram; and 3) Measurement of near point of convergence (NPC). Reading ability was examined by: 1) a reading comprehension test and 2) the Developmental Eye Movement Test (DEM), which evaluates saccadic speed and accuracy. RESULTS: Convergence amplitudes on a distant target and on a near stereogram were correlated with the DEM score (P = 0.005/0.02, r = -0.38/-0.32 and P < 0.001/0.002, r = -0.53/-0.53 for break/recovery respectively), while NPC and convergence on a near non-accommodative target did not. Reading comprehension test score was not correlated with any of the convergence measurements. CONCLUSIONS: Convergence amplitude measured while accommodation is controlled was correlated with the DEM score, which evaluates saccadic speed and accuracy. Further study to evaluate whether improvement in vergence control improves DEM scores is needed.

Accommodation, Ocular↗