ABSTRACT: Biometric procedures such as keratometry performed shortly after contact procedures like gonioscopy and applanation tonometry could affect the validity of the measurement. This study was conducted to understand the short-term effect of gonioscopy on corneal curvature measurements and surface topography based Simulated Keratometry and whether this would alter the power of an intraocular lens implant calculated using post-gonioscopy measurements. We further compared the effect of the 2-mirror (Goldmann) and the 4-mirror (Sussman) Gonioscopes.
A prospective clinic-based self-controlled comparative study. 198 eyes of 99 patients, above 50 years of age, were studied. Exclusion criteria included documented dry eye, history of ocular surgery or trauma, diabetes mellitus and connective tissue disorders. Auto-Keratometry and corneal topography measurements were obtained at baseline and at three follow-up times - within the first 5 minutes, between the 10th-15th minute and between the 20th-25th minute after intervention. One eye was randomized for intervention with the 2-mirror gonioscope and the other underwent the 4-mirror after baseline measurements. t-tests were used to examine differences between interventions and between the measurement methods. The sample size was calculated using an estimate of clinically significant lens implant power changes based on the SRK-II formula.
Clinically and statistically significant steepening was observed in the first 5 minutes and in the 10-15 minute interval using topography-based Sim K. These changes were not present with the Auto-Keratometer measurements. Although changes from baseline were noted between 20 and 25 minutes topographically, these were not clinically or statistically significant. There was no significant difference between the two types of gonioscopes. There was greater variability in the changes from baseline using the topography-based Sim K readings.
Reversible steepening of the central corneal surface is produced by the act of gonioscopy as measured by Sim K, whereas no significant differences were present with Auto-K measurements. The type of Gonioscope used does not appear to influence these results. If topographically derived Sim K is used to calculate the power of the intraocular lens implant, we recommend waiting a minimum of 20 minutes before measuring the corneal curvature after gonioscopy with either Goldmann or Sussman contact lenses.
BMC Ophthalmology 02/2006; 6:26. · 1.00 Impact Factor
Techniques in Ophthalmology 11/2005; 3(4):165.
ABSTRACT: To compare the histopathologic stage of temporal arteritis observed in biopsy-positive specimens with clinical symptoms and erythrocyte sedimentation rates (ESR). Also, to compare the degree of involvement of biopsies from the right versus left side in patients receiving bilateral biopsies.
Retrospective case series.
Thirty-seven patients, 30 of whom received unilateral biopsies and 7 of whom had bilateral biopsies.
Biopsy specimens were reviewed and assigned a severity score on the basis of the presence of histopathologic features known to be associated with temporal arteritis. The charts for these patients were then reviewed, and patients' clinical symptoms were classified by use of an ordinal scale of severity. The first level of severity entailed headache or superficial pain without any other symptoms. The second level included constitutional symptoms such as weight loss, anorexia, fever, and fatigue. The third level of severity included the presence of visual manifestations. The ESR values were also recorded from patients' charts and examined as a continuous variable.
There is a statistically significant correlation between histopathologic stage of disease observed in biopsy specimens and clinical presentation. (P < 0.0001) The biopsy severity did not correlate significantly with ESR values (P = 0.09). There was significant variation of ESR values among the 3 levels of clinical severity (analysis of variance test yielded P = 0.04). By use of the independent samples t test, we found that mean ESR values from patients with constitutional symptoms and visual symptoms were not statistically different (P nonsignificant), yet patients with only headache/superficial tenderness had significantly lower ESR values than the rest of our patient population (P = 0.009). Last, we found that the mean difference in biopsy severity was significantly above zero (P < 0.001) when comparing simultaneous bilateral biopsy specimens.
Because of the strong correlation between biopsy severity and clinical presentation, this study supports the use of temporal artery biopsy to identify patients' risk for complications caused by temporal arteritis. Furthermore, this study indicates that ESR may be more elevated in patients with constitutional or visual symptoms than in patients with headache or scalp pain. Finally, the pathologic grade of the disease may differ significantly from 1 side to the contralateral side.
Ophthalmology 08/2005; 112(7):1293-8. · 5.45 Impact Factor
ABSTRACT: Sun glare decreases athletes' contrast sensitivity and impairs their ability to distinguish objects from background. Many commercial products claim to reduce glare but have not been proven effective in clinical studies.
To determine whether glare-reducing products such as eye black grease and antiglare stickers reduce glare and improve contrast sensitivity during sunlight exposure.
We tested 46 subjects for contrast sensitivity using a Pelli-Robson contrast chart. Each subject served as an internal control and then was randomized to either application of eye black grease, antiglare stickers, or petroleum jelly at the infraorbital rim. All testing was performed in conditions of unobstructed sunlight.
Analysis of variance revealed a significant difference between eye black grease (mean +/- SD, Pelli-Robson value, 1.87 +/- 0.09 logMAR units) and antiglare stickers (1.75 +/- 0.14 logMAR units) in binocular testing (P =.02). No statistical difference was found between the groups in right eyes, left eyes, or in combined data from the right and left eyes. Paired t tests demonstrated a significant difference between control (mean +/- SD, 1.77 +/- 0.14 logMAR units) and eye black grease (1.87 +/- 0.09 logMAR units) in binocular testing (P =.04). There was also a significant difference between control (mean +/- SD, 1.65 +/- 0.05 logMAR units) and eye black grease (1.67 +/- 0.06 logMAR units) in combined data from the right and left eyes (P =.02).
Eye black grease reduces glare and improves contrast sensitivity in conditions of sunlight exposure compared with the control and antiglare stickers in binocular testing.
Archives of Ophthalmology 08/2003; 121(7):997-1001. · 3.71 Impact Factor