scholarly journals Are Contrast Sensitivity Functions Impaired in Insulin Dependent Diabetics Without Diabetic Retinopathy?

1999 ◽  
Vol 42 (4) ◽  
pp. 133-138 ◽  
Author(s):  
Vladimír Liška ◽  
Miroslav Dostálek
Keyword(s):  
Visual Acuity ◽  
Diabetic Retinopathy ◽  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Dependent Diabetes Mellitus ◽  
Control Group ◽  
Study Group ◽  
Sensitivity Functions ◽  
Spatial Frequencies ◽  
Insulin Dependent

Purpose: To confirm the influence of multilevel metabolic disturbance of insulin dependent diabetes mellitus (IDDM) on the vision even before the onset of the other changes routinely evaluated by ophthalmologists. Methods: Contrast sensitivity functions (CSFs) were estimated using the VCTS 6500 board. The standardised measurement procedure was performed. The value of the threshold contrast sensitivity was obtained for five spatial frequencies (1.5 - 3 - 6 - 12 - 18 c/deg). Other data was collected (duration of diabetes, BCVA, funduscopy, fluoresceine angiography, HbA1C). The study group consisted of 48 IDDM patients (94 eyes) without diabetic retinopathy and with Snellen BCVA > 1.0. The control group (56 normals, 98 eyes) was age and BCVA matched. Results: Highly statistically significant decrease of the CSFs in all spatial frequencies in the study group was obtained. Correlation between duration of the diabetes and impaired degree of CSFs was present in the middle spatial frequency. No significant changes in CSFs were found among patients with pathological value of glycated hemoglobin HbA1c (>7.8 %). Conclusions: If compared with routinely used Snellen visual acuity, the CSFs are more complex descriptors of the subjects vision abilities. IDDM has an influence on these sensitive functions, especially during examination in the middle spatial frequency of 6 and 12 c/deg, before disturbing visual acuity and before changes in the retinal morphology. Decrease of CSFs was influenced mainly by the patients’ age and partially (in the middle spatial frequency) by the IDDM duration.

scholarly journals Lutein-Containing Antioxidants in Patients with Primary Open-Angle Glaucoma and Dry Type of Age-Related Macular Degeneration

2018 ◽  
Vol 15 (3) ◽  
pp. 339-347 ◽  
Author(s):  
D. A. Dorofeev
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Age Related Macular Degeneration ◽  
Control Group ◽  
Study Group ◽  
Age Related ◽  
Spatial Frequencies ◽  
Spatial Contrast Sensitivity

Objective.To assess the dynamics of structural-functional markers in patients with combined pathology: primary open-angle glaucoma (POAG) and age-related macular degeneration (AMD) with the background of lutein-containing drugs at long-term follow-up.Patients and Methods.The period of research was from November 2016 to January 2018; A parallel prospective study of patients (88 eyes), mean age 67.81 ± 8.41 (M ± σ); 67.64 (63.14; 73.08) (Me, Q25%, Q75%) years with combined pathology POAG and AMD (AREDS I and II). Patients were divided into 2 groups, the first group — a study group received Retinorm, by 1 capsule 3 times a day during a meal for 1 year, a second control group of 17 patients (32 eyes) did not receive lutein-containing medicines during the observation period. The study group consisted of 29 patients (55 eyes). There were 7 males and 22 females among them. The control group consisted of 19 patients (33 eyes), 2 males and 17 females among them. Visual acuity, standard automatic computer perimetry, optical coherence tomography, determination of spatial contrast sensitivity was carried out in all patients at the beginning of the study and after 1 year.Results.The maximum correlated visual acuity (MCVA) according to the table ETDRS increased in the study group and decreased in the control group, 95% the confidence interval for the changes in the MCVA: 0.1813636; 1.018182; 1.927273 и –3.878788; –2.393939; –0.8477273 (optotypes), respectively (W = 499.5; p = 0,0002919). Statistically significant changes in the thickness of the layer of nerve fibers of the retina (RNFL) neither in the middle nor in the sectors was revealed, and the thickness of the retina in oval foveal zone by sector: upper, temporal and lower statistically significantly decreased in the control group, while remaining unchanged in the observation group (р < 0.05). Spatial contrast sensitivity (SCS) after 1 year of use Retinorm remained at the same level in the control group, while there was a statistically significant increase in spatial contrast sensitivity in the main group, especially at high spatial frequencies is observed (р < 0.05).Conclusion.The results of the study indicate a positive effect of Retinorm used for 1 year. It was reflected in the improvement visual acuity in the distance, improvement of spatial contrast sensitivity, especially at high spatial frequencies, and the preservation of structural retinal indices both in the foveal zone and peripapillary.

Contrast Sensitivity and Visual-Field Thresholds in Patients with Thyroid Optic Neuropathy

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 194-194
Author(s):  
J Jankauskiene ◽  
R Lukauskiene ◽  
B Mickiene
Keyword(s):  
Visual Acuity ◽  
Visual Field ◽  
Contrast Sensitivity ◽  
Optic Neuropathy ◽  
Control Group ◽  
Ophthalmological Examination ◽  
Threshold Test ◽  
Spatial Frequencies ◽  
Snellen Visual Acuity ◽  
The Mean

Thyroid optic neuropathy is one of the most troubling complications of endocrine ophthalmopathies. It is related to the degree of extraocular muscle swelling in the apex of the orbit. The purpose of this study was to investigate contrast sensitivity and visual-field thresholds in patients with thyroid optic neuropathy. We examined twenty-two patients aged 29 – 63 years (mean 45.3 years). The control group consisted of fifteen healthy persons of similar age. Contrast sensitivity was measured by means of Volkov's charts (sinusoidal gratings) at eight spatial frequencies from 17.5 to 0.46 cycles deg−1. The visual field was investigated with a static automatic perimeter (Allgan Humphrey Field Analyzer) by means of the central 30-2 threshold test. All patients underwent a complete ophthalmological examination including best corrected Snellen visual acuity, fundus copy, and proptosis measurement with the Hertel exophthalmometer. The mean proptosis of patients was 19.4 mm. Fifteen of the patients had decreased visual acuity. Contrast sensitivity at low spatial frequencies was significantly reduced in the patients. It was established that a reduction of visual-field threshold accompanies the decrease of visual acuity. Our results show that contrast sensitivity and visual-field threshold testing are very sensitive at detecting early optic neuropathy and may be a useful means of following patients after treatment.

Spatial Integration of Objectively Equiluminous Chromatic Gratings

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 200-200
Author(s):  
M I Kankaanpää ◽  
J Rovamo ◽  
H T Kukkonen ◽  
J Hallikainen
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Spatial Integration ◽  
Chromatic Contrast ◽  
Shape Difference ◽  
Sensitivity Functions ◽  
Spatial Frequencies ◽  
Low Pass ◽  
Chromatic Aberrations ◽  
Chromatic Contrast Sensitivity

Contrast sensitivity functions for achromatic and chromatic gratings tend to be band-pass and low-pass in shape, respectively. Our aim was to test whether spatial integration contributes to the shape difference found at low spatial frequencies. We measured binocular chromatic contrast sensitivity as a function of grating area for objectively equiluminous red - green and blue - yellow chromatic gratings. Chromatic contrast refers to the Michelson contrast of either of the two chromatic component gratings presented in counterphase against the combined background. Grating area ( A) varied from 1 to 256 square cycles ( Af2) at spatial frequencies ( f) of 0.125 – 4.0 cycles deg−1. We used only horizontal gratings at low and medium spatial frequencies to minimise the transverse and longitudinal chromatic aberrations due to ocular optics. At all spatial frequencies studied, chromatic contrast sensitivity increased with grating area. Ac was found to be constant at low spatial frequencies (0.125 – 0.5 cycles deg−1) but decreased in inverse proportion to increasing spatial frequency at 1 – 4 cycles deg−1. Thus, spatial integration depends similarly on spatial frequency for achromatic (Luntinen et al, 1995 Vision Research35 2339 – 2346) and chromatic gratings, and differences in spatial integration do not contribute to the shape difference of the respective contrast sensitivity functions.

scholarly journals Orthokeratology in Moderate Myopia: A Study of Predictability and Safety

2020 ◽  
Author(s):  
Kirti Singh ◽  
Mainak Bhattacharyya ◽  
Abhishek Goel ◽  
Ritu Arora ◽  
Nikhil Gotmare ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Contact Lenses ◽  
Corneal Thickness ◽  
Case Series ◽  
Tear Film ◽  
Control Group ◽  
Study Group ◽  
Soft Contact Lenses

Purpose: Literature is relatively silent on safety profile and predictability of orthokeratology lenses in terms of myopia correction and prevention of further progression, especially in semi-tropical countries; this study was designed to fill this gap. Methods: This prospective, intervention case series enrolled 30 eyes of 30 patients with myopia up to –5.5 diopters (D). Patients were randomized into two groups of 15 each; the study group was prescribed overnight orthokeratology (OK) lenses, while the control group used daily wear conventional soft contact lenses. Follow-up examinations were performed after 1 h and 6 h, and then at 1, 7, 15, 30 days, and 4 months post lens wear. Uncorrected visual acuity (UCVA), contrast sensitivity, keratometry, central corneal thickness (CCT), and tear film break up time (TBUT) were evaluated at each follow-up examination. Results: All patients attained a visual acuity of 0.00 Logarithm of the Minimum Angle of Resolution (logMAR) after one week of lens use, which was maintained throughout the study period. While patients allotted to the study group had a gain of 8.1 Snellen lines (UCVA), those in the control group gained 8.9 lines (BCVA) at the end of follow-up period. In the OK group, cornea showed a flattening of 0.8 D (mean keratometry) after single overnight usage of OK lens and overall flattening of 1.2 D compared to baseline, at the end of four months. The change in contrast sensitivity, corneal endothelial specular count, axial length and tear film status was not significant in either group. Conclusion: Orthokeratology is an effective and safe modality to correct moderate myopia in motivated young adults. No side effects were encountered after a short-term follow-up in participants who resided in semi-tropical environments.

scholarly journals A STUDY TO ASSESS THE CONTRAST SENSITIVITY OF THE HUMAN VISUAL SYSTEM IN PATIENTS WITH OR WITHOUT DIABETES IN A TERTIARY CARE HOSPITAL

2020 ◽  
pp. 24-26
Author(s):  
NIKITA RAJGADIA ◽  
BINDU BHASKARAN ◽  
N. DIVYA ◽  
V. PANIMALAR A. VEERAMANI ◽  
SYEDA SADIYA IKRAM
Keyword(s):  
Visual Acuity ◽  
Visual Impairment ◽  
Contrast Sensitivity ◽  
Tertiary Care ◽  
Dependent Diabetes Mellitus ◽  
Control Group ◽  
P Value ◽  
Care Hospital ◽  
Type Ii ◽  
Department Of Ophthalmology

Objective: The objective of our study was to assess the variations in contrast sensitivity values of normoglycemic subjects and that of type II diabetic subjects of the same age group. It was also aimed at finding the visual acuities and study the associations of it with contrast sensitivity if any. Methods: It was a hospital-based comparative cross-sectional descriptive study conducted in the out-patient department of the Department of Ophthalmology, Saveetha Medical College, Hospital, Chennai. Visual Acuity and Contrast Sensitivity of 50 Type II Diabetic individuals and 50 age-equivalent control group subjects were measured using the Snellen’s chart and Pelli-Robson chart, respectively, during the months of January to March 2020. Results: Contrast Sensitivity measurements from 50 subjects with Non-Insulin dependent Diabetes Mellitus (NIDDM) were obtained. The subjects were the ones who had minimal or no diabetic retinopathy. It was observed that there is a significant association between reduced contrast sensitivity and Diabetes (P value<.00008). We also noted that CS may be reduced without corresponding loss of Visual Acuity. Hence, both visual acuity and contrast sensitivity measurements are helpful in the assessment of visual impairment due to diabetic eye disease. Conclusion: The contrast sensitivity can be seen as an early marker for visual impairment in diabetic eye care.

A Comparative Study of the Spatial-Frequency Spectrum of Different Letter Optotypes and its Role in Target Recognition

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 214-214 ◽  
Author(s):  
S A Koskin ◽  
V F Danilichev ◽  
Y E Shelepin
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Frequency Spectrum ◽  
Brain Diseases ◽  
Sinusoidal Grating ◽  
Sensitivity Functions ◽  
Spatial Frequencies ◽  
Wide Range ◽  
Narrow Frequency Band ◽  
Spatial Frequency Spectrum

We studied the contrast sensitivity functions (CSFs) in patients with different eye and brain diseases using a computerised sinusoidal grating test with a wide range of frequencies (0.4 – 19.0 cycles deg−1), the Pelli - Robson chart and a new chart with frequency-filtered Snellen optotypes. The patients had different CSF curves with a decrease of contrast sensitivity in the low, middle, or high frequencies depending on their main disease (refraction anomalies, cataract, glaucoma, neuritis of optic nerve, brain tumours, etc). Analysis showed that optotypes in the Pelli - Robson chart have a wide-range spatial-frequency spectrum, and optotype recognition is determined not only by low spatial frequencies. We find that the recognition of standard Sloan's optotypes is determined mostly by sensitivity in the range of 9.4 – 14.0 cycles deg−1. At the same time we measured contrast sensitivity using the new filtered Snellen optotypes. Our calculations support our earlier suggestions that the new filtered optotypes have a narrow-band spatial-frequency spectrum, thus enabling selective measurement of contrast sensitivity in each narrow frequency band.

Acuity and contrast sensitivity of the bluegill sunfish and how they change during optic nerve regeneration

2007 ◽  
Vol 24 (3) ◽  
pp. 319-331 ◽  
Author(s):  
D.P.M. NORTHMORE ◽  
D.-J. OH ◽  
M.A. CELENZA
Keyword(s):  
Optic Nerve ◽  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Cutoff Frequency ◽  
Lepomis Macrochirus ◽  
High Spatial Frequency ◽  
Contrast Threshold ◽  
Bluegill Sunfish ◽  
Sensitivity Functions ◽  
Spatial Frequencies

Spatial vision was studied in the bluegill sunfish, Lepomis macrochirus (9.5–14 cm standard length) to assess the limitations imposed by the optics of the eye, the retinal receptor spacing and the retinotectal projection during regeneration. Examination of images formed by the dioptric elements of the eye showed that spatial frequencies up to 29 c/° could be imaged on the retina. Cone spacing was measured in the retina of fresh, intact eyes. The spacing of rows of double cones predicted 3.4 c/° as the cutoff spatial frequency; the spacing between rows of single and double cones predicted 6.7 c/°. Contrast sensitivity functions were obtained psychophysically in normals and fish with one regenerating optic nerve. Fish were trained to orient to gratings (mean luminance = 25 cd/m2) presented to either eye. In normals, contrast sensitivity functions were similar in shape and bandwidth to those of other species, peaking at 0.4 c/° with a minimum contrast threshold of 0.03 and a cutoff at about 5 c/°, which was within the range predicted by cone spacing. Given that the optical cutoff frequency exceeds that predicted by cone spacing, it is possible that gratings could be detected by aliasing with the bluegill's regular cone mosaic. However, tests with high contrast gratings up to 15 c/° found no evidence of such detection. After crushing one optic nerve in three trained sunfish, recovery of visual avoidance, dorsal light reflex and orienting to gratings, were monitored over 315 days. At 64–69 days postcrush, responses to gratings reappeared, and within 2–5 days contrast sensitivity at low (0.15 c/°) and medium (1.0 c/°) spatial frequencies had returned to normal. At a high spatial frequency (2.93 c/°) recovery was much slower, and complete only in one fish.

Influence of corneal guttae and nuclear cataract on contrast sensitivity

2020 ◽  
pp. bjophthalmol-2019-315206
Author(s):  
Victor A Augustin ◽  
Julia M Weller ◽  
Friedrich E Kruse ◽  
Theofilos Tourtas
Keyword(s):  
Contrast Sensitivity ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Control Group ◽  
Study Group ◽  
Nuclear Cataract ◽  
Inclusion Criteria ◽  
Corneal Densitometry ◽  
Spatial Frequencies ◽  
Corneal Volume

AIMSTo evaluate the contrast sensitivity in patients with nuclear cataract and corneal guttae compared to patients with nuclear cataract without guttae.METHODSIn this retrospective, single-centre case series, 50 eyes of 50 patients fulfilling the inclusion criteria were enrolled. Patients with corneal guttae and nuclear cataract (n=25, study group) underwent triple Descemet membrane endothelial keratoplasty (DMEK). Patients with nuclear cataract and healthy corneas underwent cataract surgery (n=25, control group). Inclusion criteria were preoperative best-corrected visual acuity ≥20/40, no corneal oedema and similar lens opacity (nuclear opalescence 2.0–2.9). Outcome measures included MARS letter and OPTEC 6500P contrast sensitivity test, corneal volume, central corneal thickness and anterior and posterior corneal densitometry.RESULTSPreoperative MARS letter and OPTEC 6500P contrast sensitivity was significantly worse in the study group (MARS: p<0.001; OPTEC 6500P: p<0.007 at low spatial frequencies in daylight with and without glare and nightlight without glare). After surgery, there was no significant difference in MARS letter contrast sensitivity between groups (p=0.225). OPTEC 6500P contrast sensitivity remained significantly lower in the study group in daylight and nightlight with and without glare at most spatial frequencies (p<0.01) postoperatively. Preoperative and postoperative corneal volume, central corneal thickness and anterior corneal densitometry were equal in both groups (p>0.05). Posterior densitometry was significantly higher in the study group than in the control group preoperatively (p<0.001) but turned into equal values postoperatively (p=0.07).CONCLUSIONSCorneal guttae cause an additional significant decrease in contrast sensitivity in eyes with nuclear cataract. This is in favour of performing a triple DMEK even in eyes with a visual acuity of ≥20/40.

scholarly journals ADAPTIVE CAPACITY IMPAIRMENT IN CHILDREN WITH INSULIN-DEPENDENT DIABETES MELLITUS AS SHOWN BY TIME INTERVAL ASSESSMENT

2021 ◽  
Vol 14 (5) ◽  
pp. 112-116
Author(s):  
YURI V. BYKOV ◽  
◽  
VLADIMIR A. BATURIN ◽  
Keyword(s):  
Diabetes Mellitus ◽  
Type I Diabetes ◽  
Insulin Dependent Diabetes Mellitus ◽  
Insulin Dependent Diabetes ◽  
Dependent Diabetes Mellitus ◽  
Control Group ◽  
Study Group ◽  
Type I ◽  
Level Of Consciousness ◽  
Insulin Dependent

Aim. The aim of the study was to diagnose and study the severity of impaired adaptive capacity in children with insulin-dependent diabetes mellitus using the method of assessment of time intervals. Material and methods. The study included 54 adolescents, aged 14 to 18 years. 27 adolescents with type I diabetes mellitus, who were urgently hospitalized in the intensive care unit in a serious condition, constituted the study group, the other 27 adolescents who were hospitalized for planned surgical intervention constituted the control group (conditionally healthy children). The diagnosis of type I diabetes mellitus was confirmed by clinical and laboratory data (hyperglycemia, ketoacidosis, impaired level of consciousness (deafening-sore). Study protocol: psychophysiological testing in adolescents was performed using the original «Rhythm» program, which presented patients with a reference sequence of sound signals and pauses between them, after which the patients played back the sound sequence using a personal computer. Adolescents in the study group were tested after diabetic ketoacidosis had subsided, glycemia had stabilized, and the level of consciousness had normalized (3–5 days after admission). The control group was tested upon admission to thehospital for planned treatment. Significance of the total index of deviations from the specified reference was determined using Student’s t-criterion. Results and discussion. Significant adaptation disorders were detected both in the study group and in the control group. However, in children with diabetes mellitus these disorders were more pronounced due to a greater shortening of the total duration of the cycle, as well as a greater aggregate index of deviations from the duration of set signals and pauses as compared to the «reference standard». Conclusion. The findings support the hypothesis that impaired adaptation mechanisms as a manifestation of desynchronization of biological rhythms may lie in the mechanism of insulin-dependent diabetes mellitus development.

Intravitreal Triamcinolone Acetonide as an Additional Tool in Pars Plana Vitrectomy for Proliferative Diabetic Retinopathy

2003 ◽  
Vol 13 (5) ◽  
pp. 468-473 ◽  
Author(s):  
J.B. Jonas ◽  
A. SÖfker ◽  
R. Degenring
Keyword(s):  
Visual Acuity ◽  
Diabetic Retinopathy ◽  
Triamcinolone Acetonide ◽  
Proliferative Diabetic Retinopathy ◽  
Pars Plana Vitrectomy ◽  
Control Group ◽  
Study Group ◽  
Intravitreal Triamcinolone ◽  
Intravitreal Triamcinolone Acetonide ◽  
Pars Plana

Purpose To evaluate the safety and efficacy of intravitreal injections of crystalline triamcinolone acetonide as an adjunctive procedure in pars plana vitrectomy for proliferative diabetic retinopathy. Methods This nonrandomized comparative study included 30 patients (32 eyes) who underwent standardized pars plana vitrectomy for treatment of proliferative diabetic retinopathy and who received an intravitreal injection of 25 mg triamcinolone acetonide at the end of surgery. Mean follow-up time was 5.60 ± 5.14 months. The study group was compared with a control group (32 eyes) matched with the study group for preoperative and intraoperative parameters and who underwent pars plana vitrectomy for proliferative diabetic retinopathy without intravitreal injection of triamcinolone acetonide. Results The study group and the control group did not vary significantly in frequency of postoperative retinal detachment, re-pars plana vitrectomy, or postoperative enucleation or phthisis bulbi, or in best postoperative visual acuity, visual acuity at end of the study, or gain in visual acuity. Conclusions In this pilot study, the study group with pars plana vitrectomy and intravitreal triamcinolone acetonide injection compared with the nonrandomized control group without intravitreal triamcinolone acetonide injection did not show a higher than usual rate of postoperative complications. As a corollary, however, the data do not suggest the adjunct use of 25 mg intravitreal triamcinolone acetonide combined with pars plana vitrectomy as treatment of proliferative diabetic retinopathy.

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