Normal Eyes (normal + eye)

Distribution by Scientific Domains


Selected Abstracts


Limbal and Bulbar Hyperaemia in Normal Eyes

OPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2008
Heiko Pult
Abstract Purpose:, To investigate the appearance of limbal and bulbar hyperaemia in normal eyes, their relationship and the inter-observer agreement of clinical grading. Methods:, The right eyes of 120 healthy, non-contact lens-wearing subjects (m = 57, f = 63, median age = 45 years, range 18,77 years) were examined by two trained observers. Limbal and bulbar hyperaemia were scored using the Cornea and Contact Lens Research Unit (CCLRU) redness grading scales interpolated into 0.1 increments. Redness of four quadrants, and overall, were assessed, and quadrant-average redness was calculated. Inter-observer agreement was assessed at the start and end of the study (20 subjects each). Results:, For limbal redness, the overall (1.62 ± 0.46) (mean units ± S.D.) was not significantly different from the quadrant-average (1.61 ± 0.40) score. For bulbar redness, the overall (2.02 ± 0.49) was higher than the quadrant-average (1.82 ± 0.39) score (p < 0.0001). Significant correlations were found between bulbar and limbal quadrants (Pearson: r , 0.43, p < 0.0001). Significant differences in redness were found between quadrants (p < 0.0001), with nasal and temporal redder than superior and inferior quadrants. Small effects of age and gender were found for limbal redness. The inter-observer 95% limits of agreement were similar at the start and end of the study. They were larger for overall (0.57) compared with quadrant-average (0.28) redness. Conclusions:, For similar populations, a limbal redness above 2.5 or a bulbar redness above 2.6 (quadrant-average) or 3.0 (overall) may be considered abnormal. Limbal and bulbar redness were correlated. Quadrant-average scores are recommended instead of overall scores, as inter-observer agreement was better. [source]


Effect of Two Different UVA Doses on the Rabbit Cornea and Lens

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2009
ejka, estmír
The aim of the present paper was to examine the irradiation effect of two doses of UVA rays (365 nm) on the rabbit cornea and lens. Corneas of anesthetized adult albino rabbits were irradiated with UVA rays for 5 days (daily dose 1.01 J cm,2 in one group of rabbits and daily dose 2.02 J cm,2 in the second group of animals). The third day after the last irradiation, the rabbits were killed, and their eyes were employed for spectrophotometrical, biochemical and immunohistochemical investigations. Normal eyes served as controls. Absorption spectra of the whole corneal centers were recorded over the UV,VIS (visible) spectral range. Levels of antioxidant and prooxidant enzymes, nitric oxide synthases and nitric oxide (indirectly measured as nitrate concentration) were investigated in the cornea. Malondialdehyde, a byproduct of lipid peroxidation, was examined in the cornea and lens. The results show that the staining for endothelial nitric oxide synthase was more pronounced in corneas irradiated with the higher UVA dose. Otherwise, UVA rays at either dose did not significantly change corneal light absorption properties and did not cause statistically significant metabolic changes in the cornea or lens. In conclusion, UVA rays at the employed doses did not evoke harmful effects in the cornea or lens. [source]


Stimulus size and the variability of the threshold response in the central and peripheral visual field

OPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 6 2002
L. S. Kim
Purpose:, The investigation of the peripheral visual field has shown considerable interest for the investigation of field loss attributed to anticonvulsant therapy. The purpose was to determine the within-visit between-subject, the between-visit between-subject, and the between-location variability of the threshold response in the normal eye with increase in stimulus eccentricity out to 60° as a function of stimulus size. Methods:, Forty-eight normal subjects attended for a total of three visits (mean age = 49.5 years, SD = 18.9, range 22,84 years). At the first visit, one randomly assigned eye of each subject was examined with the Humphrey Field Analyzer 750 (Carl Zeiss, Jena, Germany) and the Full Threshold algorithm using Programs 30,2 and 60,4 and stimulus sizes III and V. The combination of stimulus size and of program, and the order of the combination within- and between-sessions, were randomized for each subject. The results of the first visit were considered as a familiarization period and were discarded. The protocol at the second and third visits was identical to that at the first visit for each subject. Results:, The ratio of the SD of the group mean sensitivity was determined at each stimulus location for stimulus size III compared with stimulus size V for Programs 30,2 and 60,4 at visit 3. The SDs were greater than unity for Program 30,2 (p < 0.0001) and for Program 60,4 (p < 0.0001) indicating greater variability for the size III stimulus. The SDs were also greater than unity for the central inner zone (p < 0.0001), central outer zone (p < 0.0001) and peripheral inner zone (p < 0.0001). The ratios in the peripheral outer zone were not quite greater than unity (p = 0.054). The ratios increased with increase in eccentricity by up to 2.7 times between 15° and 30° eccentricity and by up to 2.7 times between 30° and 60° eccentricity. The group mean ratio did not vary significantly between the two visits for Program 30,2 stimulus size III (p = 0.563), Program 60,4 stimulus size III (p = 0.935) and for Program 60,4 stimulus size V (p = 0.005). However, the group mean SD was lower at visit 3 compared with visit 2 for Program 30,2 stimulus size V (p = 0.0004). The SDs associated with the extreme peripheral locations in the superior and nasal fields were smaller for stimulus size III because the threshold was frequently attenuated by lid and facial contour. Conclusions:, Considerably narrower confidence limits for normality for the peripheral regions of Program 30,2 and for 60,4 are demonstrated with the use of Goldmann size V. [source]


Dynamic wavefront aberrations and visual acuity in normal and dry eyes

CLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 3 2009
Yan Wang MD
Purpose:, The aim was to study the dynamic properties of wavefront aberrations and visual acuity in normal and dry eyes. Methods:, Thirty dry-eye patients and 27 normal subjects participated in this study. Multi-file mode of a Hartmann-Shack wavefront sensor was used to measure dynamic wavefront aberrations for a period of 45 seconds. Dynamic measurements of visual acuity (VA) were made for 150 seconds using a multi-functional VA tester. Standard deviation of the measurements (RMS or VA) over the testing period was used to estimate instability of the dynamic wavefront aberration and VA. Results:, For most subjects, both wavefront aberration and VA changed over time and the instability varied substantially among individuals. Blink-dependent fluctuation in wavefront aberration or VA was observed for some dry-eye subjects. On average, the dry-eye group had greater instability than the normal group in either the higher order wavefront aberrations (t = 2.09, p = 0.03, for OD; t = 3.76, p = 0.001, for OS) or the VA (t = 2.09, p = 0.02, for OD; t = 204, p = 0.03, for OS). Instability of VA in the dry-eye group was significantly correlated with blink rate (r = 0.28, p = 0.02). Conclusion:, Dynamic changes in wavefront aberrations and VA are highly individual dependent, while the dry eye tends to be less stable than the normal eye. The results suggest that tear-film fluctuation might play a role in determining dynamic wavefront aberration and VA, however, contributions from other factors should not be overlooked. For dry eye, dynamic change in VA depends on blink rate. [source]


Can true monocular keratoconus occur?

CLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 6 2003
Anthony J Phillips MPhil FCOptom FAAO FVCO FCLSA FBOA(HD) DipCLP
Evidence increasingly supports keratoconus as an inherited, genetic disorder. If this is the case, it would be expected to express itself as a binocular condition even though variable expression of the gene may show differing levels in the two eyes. It is a common occurrence in specialist contact lens practices to see pseudo-monocular keratoconus, that is, an overt clinical level of the condition in one eye and forme fruste keratoconus in the other. The advent of videokeratoscopy has shown almost every case of apparent monocular keratoconus to be different expressions of the condition in the two eyes. Nevertheless, rare cases of the condition are seen that appear to be truly monocular. Such a case is presented in which the condition has been present for more than 23 years. The age of the subject makes the future onset of keratoconus highly unlikely and videokeratoscopy does not show the presence of forme fruste in the ,good' eye. There is no history of monocular eye rubbing. Pachymetry shows the normal eye to be well within the range of normal corneal thickness, while the keratoconus in the other eye is sufficiently advanced to warrant corneal grafting. Thus, it is a case of true monocular keratoconus and represents an extreme example of variable gene expression. [source]


Magnetic Resonance Imaging in Patients Diagnosed With Papilledema: A Comparison of 6 Different High-Resolution T1- and T2(*)-Weighted 3-Dimensional and 2-Dimensional Sequences

JOURNAL OF NEUROIMAGING, Issue 2 2002
Johannes Seitz MD
ABSTRACT Purpose. To evaluate visualization and signal characteristics of macroscopic changes in patients with ophthalmologically stated papilledema and to find a suitable high-resolution magnetic resonance imaging (MRI) protocol. Method. Nine consecutive patients with 12 ophthalmologically stated papilledemas underwent MRI of the head and orbits, which consisted of the following high-resolution sequences: 3-dimensional (3D), T2*-weighted (T2*w) constructive interference in steady-state sequence (CISS); 3D, T1-weighted (T1w) magnetization prepared-rapid gradient echo sequence (MP-RAGE) (with and without intravenous contrast medium); transverse 3D and 2-dimensional (2D) (2mm), T2-weighted (T2w) turbo spin echo (TSE); transverse 2D (2mm), contrast-enhanced T1w TSE with fat-suppression technique; and transverse 2D (5mm), T2w TSE. A quantitative and qualitative evaluation of the papilla, optic nerve, optic nerve sheath, optic chiasm, and the brain was performed. The 6 high-resolution sequences were compared. Results. The elevation of the optic disc into the optic globe in ophthalmologically stated papilledema was best visualized in T2w, 3D CISS sequence. The pathological contrast enhancement was best seen in T1w contrast-enhanced 2D TSE sequence with fat-suppression technique. The mean width of the optic nerve sheath directly behind the globe was 7.54 mm (± 1.05 mm) in the pathological eyes, compared to 5.52 mm (± 1.11 mm) in the normal eyes. In all patients, the cerebral indices calculated showed no signs of increased intracranial pressure or other abnormalities changing the volume of the brain or ventricles. The contrast of the orbital fat versus the optic nerve sheath, the optic nerve sheath versus the surrounding cerebrospinal fluid (CSF), the surrounding CSF versus the optic nerve, the optic chiasm versus the CSF, and the optic papilla versus the optic globe were best visualized in the 3D, T2*w CISS sequence. An enhancement of the swollen optic nerve head was best seen in all 12 cases in the T1w contrast-enhanced 2D TSE sequence with fat-suppression technique. Conclusion. An MRI protocol consisting of a 5-mm transverse T2w TSE sequence; a T2*w, 3D CISS sequence; a T1w, 3D MP-RAGE sequence with and without contrast medium; and a transverse T1w, (2-mm) 2D TSE sequence with fat-suppression technique with intravenous contrast medium is suitable to visualize the macroscopic changes in papilledema. In addition, this combination is an excellent technique for the examination of the orbits and the brain. [source]


Limbal and Bulbar Hyperaemia in Normal Eyes

OPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2008
Heiko Pult
Abstract Purpose:, To investigate the appearance of limbal and bulbar hyperaemia in normal eyes, their relationship and the inter-observer agreement of clinical grading. Methods:, The right eyes of 120 healthy, non-contact lens-wearing subjects (m = 57, f = 63, median age = 45 years, range 18,77 years) were examined by two trained observers. Limbal and bulbar hyperaemia were scored using the Cornea and Contact Lens Research Unit (CCLRU) redness grading scales interpolated into 0.1 increments. Redness of four quadrants, and overall, were assessed, and quadrant-average redness was calculated. Inter-observer agreement was assessed at the start and end of the study (20 subjects each). Results:, For limbal redness, the overall (1.62 ± 0.46) (mean units ± S.D.) was not significantly different from the quadrant-average (1.61 ± 0.40) score. For bulbar redness, the overall (2.02 ± 0.49) was higher than the quadrant-average (1.82 ± 0.39) score (p < 0.0001). Significant correlations were found between bulbar and limbal quadrants (Pearson: r , 0.43, p < 0.0001). Significant differences in redness were found between quadrants (p < 0.0001), with nasal and temporal redder than superior and inferior quadrants. Small effects of age and gender were found for limbal redness. The inter-observer 95% limits of agreement were similar at the start and end of the study. They were larger for overall (0.57) compared with quadrant-average (0.28) redness. Conclusions:, For similar populations, a limbal redness above 2.5 or a bulbar redness above 2.6 (quadrant-average) or 3.0 (overall) may be considered abnormal. Limbal and bulbar redness were correlated. Quadrant-average scores are recommended instead of overall scores, as inter-observer agreement was better. [source]


Comparison of optical coherence tomography and fundus photography for measuring the optic disc size

OPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2006
Aljoscha S. Neubauer
Abstract Purpose:, To assess the agreement and repeatability of optic nerve head (ONH) size measurements by optical coherence tomography (OCT) as compared to conventional planimetry of fundus photographs in normal eyes. Methods:, For comparison with planimetry the absolute size of the ONH of 25 eyes from 25 normal subjects were measured by both OCT and digital fundus photography (Zeiss FF camera 450). Repeatability of automated Stratus OCT measurements were investigated by repeatedly measuring the optic disc in five normal subjects. Results:, Mean disc size was 1763 ± 186 vertically and 1632 ± 160 ,m horizontally on planimetry. On OCT, values of 1772 ± 317 ,m vertically (p = 0.82) and a significantly smaller horizontal diameter of 1492 ± 302 ,m (p = 0.04) were obtained. The 95% limits of agreement were (,546 ,m; +527 ,m) for vertical and (,502 ,m; +782 ,m) for horizontal planimetric compared to OCT measurements. In some cases large discrepancies existed. Repeatability of automatic measurements of the optic disc by OCT was moderately good with intra-class correlation coefficients (ICC) of 0.78 horizontally and 0.83 vertically. The coefficient of repeatability indicating instrument precision was 80 ,m for horizontal and 168 ,m for vertical measurements. Conclusions:, OCT can be used to determine optic disc margins in moderate agreement with planimetry in normal subjects. However, in some cases significant disagreement with photographic assessment may occur making manual inspection advisable. Automatic disc detection by OCT is moderately repeatable. [source]


The prospects for super-acuity: limits to visual performance after correction of monochromatic ocular aberration

OPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 6 2003
W. N. Charman
Abstract It has recently been suggested that correction of the monochromatic aberration of the eye could lead to substantial improvements in visual acuity and contrast sensitivity function. After consideration of the best-corrected visual acuity of normal eyes, the optical and neural limits to visual performance are reviewed. It is concluded that, even if current problems with the accuracy of the suggested techniques of aberration correction, through corneal excimer laser ablation or customised contact lenses, can be overcome, changes in monochromatic ocular aberration over time, the continuing presence of chromatic aberration, errors of focus associated with lags and leads in accommodation, and other factors, are likely to result in only minor improvements in the high-contrast acuity performance of most normal eyes being produced by attempted aberration control. Significant gains in contrast sensitivity might, however, be achievable, particularly under mesopic and scotopic conditions when the pupil is large, provided that correct focus can be maintained. In the immediate future, reduction of the high levels of aberration that are currently found in eyes that have undergone refractive surgery and in some abnormal eyes should bring useful benefits. [source]


2167: Tear film biomarkers as prognostic indicators for recurrent pterygium

ACTA OPHTHALMOLOGICA, Issue 2010
N ZAKARIA
Purpose The aim of this project is to establish the use of IL-6, IL-8 and VEGF as biomarkers in the tear film for early detection of recurrent pterygium. Methods Cytometric Bead Array (CBA) kits will be used to perform multicytokine assays in the tear samples of eyes having pterygium before and after surgical resection of the pterygia. This technique utilizes flow cytometry to determine the concentrations of multiple analytes namely IL-6, IL-8 and VEGF (proposed biomarkers) present in small volumes of tear fluid.Patients with pterygia showing corneal encroachment and requiring surgical excision will be recruited in this study along with a second population of control subjects consisting of individuals with no history of eye diseases or contact lens wear. After instilling a local anesthetic, 3 drops of normal saline will be applied and the at least 50µl of the diluted epithelial secretions collected and stored at -80°C for CBA analysis. From the results we can determine the baseline levels of IL-6, IL-8 and VEGF present in normal epithelial secretions and correlate it with potentially higher levels in the eyes of patients with pterygia. By collecting post op epithelial secretions at different time points along with regular ocular surface photographs and grading of any recurrent pterygia we will be able to ascertain the role of these cytokines and growth factors as biomarkers for recurrent pterygia. Conclusion By establishing higher tear film levels of IL-6, IL-8 and VEGF in eyes with pterygia compared to normal eyes and the return to baseline levels post excision we can begin to ascertain the role of these key players in the pathogenesis of pterygia. [source]


Corneal hysteresis measured with the Ocular Response Analyzer® in normal and glaucomatous eyes

ACTA OPHTHALMOLOGICA, Issue 1 2010
Olivia Abitbol
Abstract. Purpose:, To identify differences in corneal hysteresis (CH) and central corneal thickness (CCT) between healthy and glaucomatous patients. Methods:, Retrospective observational study. One hundred and thirty-three eyes of 75 healthy and 58 glaucomatous patients were included. CH was measured in each patient using Ocular Response Analyzer. CCT was determined by ultrasonic pachymetry. For each patient, one eye was randomly selected. We used a Student t -test to search for significant differences between the different groups (p<0.05). Results:, In healthy and glaucomatous eyes, mean CH values were 10.46 ± 1.6 and 8.77 ± 1.4 mm Hg, respectively. Mean CCT values were 560.2 ± 36.3 and 535.3 ± 42.7 ,m, respectively. CH and CCT were significantly lower in glaucomatous eyes than in normal eyes, (p<0.05). Discussion:, In our series, CH was lower in glaucomatous than in normal eyes. The relationship between glaucoma, IOP, and ocular structures may not be confined to the consideration of CCT. A low CH value could be responsible for under-estimation of IOP. CH could also be a risk factor for glaucoma, independent of IOP. Further studies are needed to support these hypotheses. Conclusion:, In our investigation, CCT and CH were significantly lower in glaucomatous eyes than in healthy eyes. [source]


Intraocular pressure change after temporal clear corneal phacoemulsification in normal eyes

ACTA OPHTHALMOLOGICA, Issue 1 2010
Inci Irak-Dersu
Abstract. Purpose:, To evaluate short- and long-term intraocular pressure (IOP) changes after temporal clear corneal phacoemulsification in normal eyes. Methods:, The charts of 266 consecutive non-glaucoma patients who underwent uneventful cataract surgery were reviewed. We recorded preoperative and postoperative (1 day, 1 week, 1 month, 3 months, 6 months, 1 year and 2 years) IOP measurements as well as anatomical properties obtained using Zeiss Humphrey IOL Master (Zeiss Meditech, Dublin, California, USA). Results:, Mean IOP reduction after cataract surgery was 8.2%, 4.6%, 6.7% and 7.8% at 3 months, 6 months, 1 year and 2 years, respectively. Lens thickness was the only anatomical characteristic that correlated significantly with IOP decrease after surgery. Conclusion:, Temporal clear corneal phacoemulsification results in a decrease in postoperative IOP that persists for 2 years following surgery. [source]


Repeatability in and interchangeability between the macular and the fast macular thickness map protocols: a study on normal eyes with Stratus optical coherence tomography

ACTA OPHTHALMOLOGICA, Issue 7 2009
Urban Eriksson
Abstract. Purpose:, To collect a normal material and to compare the macular and the fast macular thickness map protocols regarding normal values and repeatability. Methods:, Sixty-seven individuals underwent three repeated scans with the macular thickness protocol; 45 of them also had three scans with the fast thickness protocol in Stratus optical coherence tomography (OCT). The maps were divided into nine ETDRS fields, where thickness values were presented. The repeatability was calculated as intraclass correlation coefficient (ICC), coefficient of variance (CV) and coefficient of repeatability (CR). For comparison between the two protocols, limits of agreement were determined according to Bland,Altman. Results:, Normal values for the two protocols were very close. Repeatability was high. ICC for all areas was 0.92,0.98. CV was less than 1% and CR was 6,8 ,m for both protocols, with the exception of the fovea in the fast protocol (where CV was 1.44% and CR 12.4 ,m). Limits of agreement between the two protocols were less than 10 ,m as a rule. Conclusion:, Normal values for the protocols are equal and they both have excellent repeatability. The fast macular map is a good alternative with the possible exception of the fovea, where variation is twice that of the macular thickness map. [source]


Comparison of static automated perimetry and semi-automated kinetic perimetry in patients with bilateral visible optic nerve head drusen

ACTA OPHTHALMOLOGICA, Issue 7 2009
Katarzyna Nowomiejska
Abstract. Purpose:, Until now there has been no standardized, systemic approach to diagnostics in patients with optic nerve head drusen (ONHD). This study compares visual field (VF) results obtained with static automated perimetry (SAP) and semi-automated kinetic perimetry (SKP) in patients with bilateral visible ONHD. Methods:, Visual fields in 26 eyes (13 patients) with ONHD were obtained by Humphrey Field Analyser II (SAP) and Octopus 101 (SKP) equipment and classified by three masked observers. Pairs of VFs were considered equivalent if the descriptions given by both methods matched. Individual reaction time (RT) was assessed during SKP. Fifteen healthy volunteers were examined as control material. Results:, Visual field pairs matched in 19 eyes (three normal VFs, 16 arcuate defects). In the remaining eight eyes SKP provided more information in concentric constriction of the VF (two eyes) and SAP provided more information on paracentral scotomas (five eyes). Sensitivity was 69% for SKP, 80% for SAP and 88% for both methods together. Mean RT assessed using SKP amounted to 909 ms in eyes with ONHD and 568 ms in normal subjects (p < 0.0003). The median examination duration was 13 mins with SKP and 11 mins with SAP (p = 0.05) in eyes with ONHD, and 8 mins in control eyes (p < 0.0001). Conclusions:, In clinical practice it is necessary to perform both SAP and SKP in patients with ONHD because the VF defects are diverse. In SKP, RT is prolonged in eyes with ONHD compared with normal eyes and SKP takes longer than SAP in ONHD eyes. [source]


Comparison of anterior chamber depth measurements taken with the Pentacam, Orbscan IIz and IOLMaster in myopic and emmetropic eyes

ACTA OPHTHALMOLOGICA, Issue 4 2009
Canan Asli Utine
Abstract. Purpose:, This study determined to assess the degree of agreement between anterior chamber depth (ACD) measurements obtained using three different devices and to analyse the relationship between ACD and spherical equivalent (SE) refraction. Methods:, In this cross-sectional study, 42 eyes of 42 patients with a mean SE of , 4.69 ± 4.61 D (range 0.00 D to , 14.88 D) were analysed. Measurements of ACD between the corneal epithelium and the anterior surface of the crystalline lens, obtained using the Pentacam, Orbscan IIz and IOLMaster, were compared. The relationships between SE and ACD measurements obtained with different devices were also investigated. The results were analysed using Bland,Altman analyses, single-sample t -test and Pearson's correlation test. Results:, Orbscan ACD measurements were an average of 0.05 mm less than Pentacam measurements (p = 0.01). IOLMaster measurements were an average of 0.06 mm less than Orbscan measurements (p < 0.001). None of the ACD values measured by any of the devices were correlated with increasing SE (p > 0.05 for all). There was a weak positive correlation between SE and the difference in ACD measurements with Pentacam and Orbscan (p = 0.04); however, the differences between Pentacam and IOLMaster ACD measurements and Orbscan and IOLMaster ACD measurements seemed to be independent of SE (p = 0.17 and p = 0.54, respectively). Conclusions:, The ACD in clinically normal eyes is measured differently by various non-ultrasonic devices. However, the observed mean error between these modalities is too small to create any noticeable difference in refractive outcome. No significant relationship was found between SE and ACD measurements obtained by Pentacam, Orbscan or IOLMaster. [source]


Temporal changes in retinal thickness after removal of the epiretinal membrane

ACTA OPHTHALMOLOGICA, Issue 4 2009
Hitoshi Aso
Abstract. Purpose:, We aimed to study the temporal aspects of the postoperative reduction of retinal thickness in eyes with epiretinal membrane after vitrectomy with peeling of the epiretinal membrane and internal limiting membrane. Methods:, In a retrospective study performed as a non-comparative, interventional case series, 16 eyes from 15 patients with idiopathic epiretinal membrane who underwent vitrectomy and removal of the epiretinal membrane were followed up using optical coherence tomography measurements. Retinal thickness in the macular area was assessed by the foveal thickness and macular volume in a circle 6 mm in diameter. Results:, Scattergrams of the foveal thickness and macular volume were best fitted with exponential curves. The average time constants of the exponential curve for foveal thickness and macular volume changes were 31 days (range 4,109 days) and 36 days (range 5,100 days), respectively. The average expected final values for foveal thickness and macular volume were 334 ,m (range 206,408 ,m) and 7.53 mm3 (range 6.57,8.66 mm3), respectively, which were significantly greater than those in normal controls (p < 0.0001, t -test). Conclusions:, Retinal thickness decreases rapidly immediately after surgical removal of the epiretinal membrane and the reduction rate gradually slows thereafter. Approximation of the exponential curve provides an estimation of final retinal thickness after surgical removal of the epiretinal membrane; final thickness is expected to be greater than in normal eyes. [source]


Frequency doubling technology and high-pass resolution perimetry in glaucoma and ocular hypertension

ACTA OPHTHALMOLOGICA, Issue 3 2003
Lada Kalaboukhova
Abstract. Purpose:, To study the correlation between frequency doubling technology perimetry (FDT) and high-pass resolution perimetry (HRP) in eyes with primary open-angle glaucoma, suspect glaucoma, ocular hypertension, and in normal eyes. Patients and Methods:, Ninety-four patients (162 eyes) were studied. Visual fields were assessed by HRP, FDT screening C-20,5 and FDT threshold C-20 programs. In eyes with a discrepancy between the test results, a comprehensive clinical examination was performed, including optic disc photography and Heidelberg retinal tomography (HRT). Results:, There was a strong correlation between HRP global deviation and the FDT mean deviation (for FDT threshold C-20 test), and between HRP score and FDT score (for FDT screening C-20,5 ). The correlation coefficients were r = ,0.83 and r = 0.77, respectively. In all, 75 eyes (46.3%) had normal HRP and FDT screening results, while 67 eyes (41.4%) showed abnormal results in both tests. In 12 eyes (7.4%) HRP was within normal limits while FDT screening was abnormal. Seven of these eyes were judged to have glaucoma; three of them had converted from ocular hypertension to glaucoma. In eight eyes (4.9%) HRP was abnormal while FDT screening was normal. Three of these were judged to have glaucoma. Thus, the sensitivity and specificity of the FDT screening test for the detection of glaucoma were 91.7% and 87.8%, respectively. Conclusion:, There was a strong correlation between FDT threshold C-20, FDT screening C-20,5 and HRP test results. Frequency doubling technology perimetry C-20,5 represents a good screening test for the detection of optic nerve damage in open-angle glaucoma. [source]


Quantitative evaluation of corneal epithelial oedema by confocal microscopy

CLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 3 2009
Naoyuki Morishige MD PhD
Abstract Background:, To develop a novel quantitative index for evaluation of corneal epithelial oedema, the pixel intensity of confocal microscopic images was measured derived from the basal cell layer (BCL) of the corneal epithelium in normal eyes, eyes before and after cataract surgery, and eyes affected by bullous keratopathy. Methods:, Five eyes of five normal volunteers, 14 eyes of 11 cataract patients and 12 eyes of 12 bullous keratopathy patients were examined by confocal microscopy. The cataract patients underwent cataract surgery, and they were examined by confocal microscopy, corneal pachymetry, and anterior fluorometry both before and at various times after surgery. The pixel intensity of BCL images obtained by confocal microscopy was measured and expressed as the BCL index. Results:, The coefficient of variation for repeated (five times) measurement of the BCL index in each of the five normal eyes was 3.4%. The BCL index was 54.8 ± 5.3 (mean ± SD) before surgery, increased significantly to 65.2 ± 10.0 on the day after surgery, and gradually decreased thereafter in the cataract patients. The time-course of the BCL index coincided well with that of corneal thickness and anterior fluorometry value. The BCL index in eyes affected by bullous keratopathy was significantly increased at 95.0 ± 6.4. Conclusion:, The BCL index was increased after cataract surgery and in eyes affected by bullous keratopathy, conditions associated with corneal epithelial oedema. This quantitative measure obtained by confocal microscopy may prove useful in the clinical evaluation of corneal epithelial oedema. [source]


Biomechanical properties of the cornea measured by the Ocular Response Analyzer and their association with intraocular pressure and the central corneal curvature

CLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 6 2009
Sandra Franco PhD
Background:, The aim of this study was to investigate the biomechanical properties of the cornea and their association with intraocular pressure (IOP), central corneal thickness (CCT) and the central corneal radius of curvature (Rc). Methods:, Eighty-three eyes were divided into two groups. The biomechanical properties of the cornea were measured in 63 normal eyes and in 20 post-laser in situ keratomileusis (LASIK) eyes. The IOP, corneal hysteresis (CH) and corneal resistance factor (CRF) were measured by the Ocular Response Analyzer (ORA). The Rc and CCT were measured using the corneal topographer Medmont E-300 and the Tomey SP-100 Handy ultrasonic pachymeter. Other parameters measured by the ORA, such as TimeIn and TimeOut, were also studied. Results:, A mean corneal hysteresis of 10.8 mmHg and CRF of 10.6 mmHg were recorded for the normal eyes. There was no significant association with central curvature. All parameters measured by the ORA showed a significant correlation with the CCT, except for the corneal-compensated intraocular pressure (IOPcc). Both IOPs measured by the ORA had the same values for the mean CH and CRF. For the post-LASIK eyes, the CH and CRF were lower than in the normal non-operated eyes. The TimeIn and the TimeOut also presented lower values for the post-LASIK eyes, suggesting that additional data can be obtained with the ORA measurements. Conclusions:, The results of this study indicate that there is no correlation between the parameters measured with the Ocular Response Analyzer and central corneal radius of curvature. Some of the biomechanical properties of the cornea studied were found to differ in the normal eyes compared to the post-LASIK eyes. [source]