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Yusuf Akar

Publications and source records attributed to Yusuf Akar.

27 records · Page 2Linked to original sources
PubMed2004

Assessment of optic nerve head topographic parameters with a confocal scanning laser ophthalmoscope.

AIM: To assess the disc area, age, sex, laterality (side of the eyes) and refractive error dependent differences in optic nerve head topographic parameters in a normal population. METHODS: Optic nerve head topographic analysis of both eyes of 551 healthy Turkish subjects aged 11-75 years (1102 eyes) was performed using a confocal scanning laser ophthalmoscope, the Heidelberg Retinal Tomograph II (HRT II). The effects of disc size, sex, laterality (side of the eyes), age and refractive error on optic nerve head topographic parameters were assessed. Subjects were divided into three different age groups (<30 years, 30-60 years, >60 years) and three different disc area groups (<2.00 mm(2), 2.00-2.25 mm(2), >2.25 mm(2)). Disc area, topography standard deviation and a total of 12 topographic parameters were calculated by HRT II for each subject. Statistical analysis was performed using Student's t-test, multiple regression analysis, Tukey-HSD test, anova and Pearson's correlation coefficient. RESULTS: A total of 543 subjects (298 women and 245 men) were included in the study. The mean disc area of the subjects was 2.12 +/- 0.47 mm(2) (range 1.16-4.98 mm(2)). The mean refractive error of the subjects was -0.58 +/- 1.71 D (range -4.75 D to +4.25 D). The mean cup shape measure was -0.21 +/- 0.07 (95% confidence interval -0.07 to -0.35). The disc area was significantly correlated with all of the topographic parameters but two; namely, the cup shape measure and the height variation contour. Significant age-related differences were detected in four parameters (mean retinal nerve fibre layer [RNFL] thickness, disc area, cup-to-disc area ratio, cup area) and significant sex-related differences were detected three parameters (mean RNFL thickness, height variation contour, RNFL cross-sectional area). However, there were no significant differences in any of the parameters for laterality and refractive error. The parameter cup shape measure did not correlate with any of the five variables investigated. CONCLUSION: Cup shape measure was the only optic nerve head topographic parameter that was independent of age, sex, disc area, laterality and the refractive error. It seems to be a promising parameter in evaluation and comparison of the optic discs of normal subjects, with different disc area, age, sex, refraction error and laterality, as being independent of the main variation factors of the disc topography.

Adolescent↗
PubMed2004

Effect of scan repetition on the reproducibility of optic nerve head topographic measurements with the Top SS.

PURPOSE: To determine the effect of scan repetition during a single visit for improved reproducibility of optic nerve head topographic measurements. METHODS: One randomly selected eye of 20 healthy subjects with no systemic or ocular disease was evaluated. Half of the subjects were under 30 years of age and the other half were older than 60 years. Five independent image series, each consisting of 10 newly recorded consecutive images, were obtained for each subject over a period of 10 weeks with a confocal scanning laser ophthalmoscope, the Top SS. Subjects were divided into two groups according to disc area being either smaller or larger than 2 mm2. Reproducibility of the measurements in three parameters (volume below, half depth area and the average depth) were calculated for each set of scans. The coefficient of variation (standard deviation divided by the mean) was taken as the measure of reproducibility. Repeated measures of analysis of variation and independent sample t-test were used for statistical analysis. Statistical significance was set as P < 0.05. RESULTS: Both age groups were found to be equally distributed with respect to sex. There were no significant intergroup differences in keratometry, pupil diameter or refractive error. Increasing the scan repetition per visit up to five improved the reproducibility of the measurements. Further increases in scans per visit reduced the reproducibility. Subjects with larger discs and older age were found to have lower coefficients of variation for topographic measurements. CONCLUSIONS: Normal subjects should be examined at least three to four times per visit to have significantly improved reliability of measurements of optic nerve head topography. Factors associated with decreased reproducibility included older age, smaller discs, and more than five scans per visit. Sex, refraction and pupil diameter were shown to have no effect on the reproducibility.

Adolescent↗
PubMed2004

Menstrual cycle dependent changes in blue-on-yellow visual field analysis of young diabetic women with severe non-proliferative diabetic retinopathy.

PURPOSE: To evaluate menstrual cycle dependent changes on blue-on-yellow visual fields of diabetic women, and to compare the results with those of healthy women. METHODS: Left eyes of 93 normally menstruating women were included in the study, comprising 45 with type-1 diabetes mellitus and severe non-proliferative diabetic retinopathy and 48 healthy controls. All subjects underwent baseline complete ocular examination and achromatic visual field analysis. Blue-on-yellow visual field tests (short-wavelength automated perimetry) were performed in both follicular (days 7-10 of the cycle) and luteal phases (days 3-6 before the bleeding) of two consecutive menstrual cycles. Visual field analyses were performed using Humphrey Field Analyser II with full threshold, central 30-2 program. Visual fields were divided into four regions: superior temporal, inferior temporal, superior nasal and inferior nasal. Visual field mean sensitivity (MS) was calculated for all regions separately. RESULTS: The mean ages of diabetic and control subjects were not significantly different (P > 0.05). Mean MS values of the diabetic group were significantly lower than that of the control group (P < 0.05). Control subjects did not demonstrate any menstrual cycle dependent changes in MS values (P > 0.05). However, diabetic women demonstrated a significant decrease in MS values in the luteal phase (P < 0.05). The decrease in MS was most marked in the nasal visual field (P < 0.05). CONCLUSION: Young diabetic women demonstrated a significant depression in visual field threshold sensitivity in the luteal phase of the menstrual cycle. Nasal visual fields are more prone to have menstrual cycle dependent threshold sensitivity depression. This should be taken into consideration in the clinical assessment of women with advanced diabetes who are at risk of glaucomatous optic neuropathy.

Adult↗
PubMed2004

The effect of the menstrual cycle on optic nerve head analysis in healthy women.

PURPOSE: To determine the effect of the menstrual cycle on optic nerve head topographic analysis in normally menstruating, healthy women. MATERIAL AND METHODS: The study included single eyes selected randomly from each of 52 healthy women with regular menstrual cycles. All subjects underwent a complete ocular examination. Optic nerve head topographic analyses were performed using a confocal scanning laser ophthalmoscope, the Heidelberg Retinal Tomograph II (HRT II, software version 1.6). The analyses were repeated three times during the menstrual cycle: in the follicular phase (days 7-10 of the cycle), at ovulation, and in the late luteal phase (days 1-3 before menstrual bleeding). Serum oestradiol, progesterone and luteinizing hormone levels were measured at each menstrual phase. RESULTS: Fourteen subjects were excluded from the study. The mean age of the subjects (n = 38) was 25.6 +/- 3.7 years (range 21-34 years). Blood oestradiol levels were significantly lower in the late luteal phase (35.8 pg/ml) (p < 0.0001). The mean disc area of the subjects was 1.94 +/- 0.33 mm(2). The neuroretinal rim area decreased significantly during the luteal phase (p < 0.001). However, the linear cup : disc ratio, cup : disc area ratio and the cup area were significantly higher during the luteal phase (p < 0.001). CONCLUSION: These observations raise the possibility that sex hormone fluctuations which occur during a normal menstrual cycle in healthy women significantly alter neuroretinal rim area and cup variables of the optic nerve head. These findings should be taken into consideration in the clinical follow-up of young women with glaucoma.

Adult↗
PubMedDate not supplied

Reproducibility of the measurements of the optic nerve head topographic variables with a confocal scanning laser ophthalmoscope.

PURPOSE: To determine the optic nerve head topographic parameters with the least variability in repeat measurements. METHODS: We randomly selected and evaluated 1 eye each of 20 healthy subjects, a total of 20 eyes. We used the confocal scanning laser ophthalmoscope (CSLO) for optic nerve head analysis. The disc area and a total of 13 parameters were determined by Top SS. Each subject was examined five times, each time on a different day, during a 2-month period. We obtained a series of five 10 x 10 degrees images for each eye per visit. Three of the five images were randomly selected to create a mean image. Coefficients of variation of each of the 13 variables studied were calculated separately by using those five different optic nerve head topographic measurements. RESULTS: The subjects were 11 women and 9 men. The mean age of the subjects was 30.5 +/- 6.9. The mean optic disc areas were 2.26 +/- 0.39 mm(2) and 1.96 +/- 0.37 mm(2) for the men and the women, respectively (P >.05). The mean coefficient of variation for measurement of the variables was found to range between 1.2% and 9.8%. The variables, cup shape, volume above, average depth, and volume below, were found to yield the best reproducible measurements. CONCLUSION: The CSLO with its highly reproducible measurements (<10% error) offers a highly objective, safe, and effective method for clinical use in measurements of the topography of the optic nerve head. The subtle differences in the variables, cup shape, volume above, average depth, and volume below, may be of vital importance in the follow-up of those diseases requiring longitudinal monitoring of the optic nerve head, namely ocular hypertension and glaucoma.

Adult↗
PubMedDate not supplied

Endoscopic transnasal dacryocystorhinostomy and bicanalicular silicone tube intubation.

PURPOSE: To evaluate the results of endoscopic transnasal dacryocystorhinostomy (ETDCR) combined with bicanalicular silicone tube intubation (BSTI) performed in 49 patients with nasolacrimal canal obstructions secondary to chronic dacryocystitis. MATERIAL AND METHODS: ETDCR combined with BSTI was applied as a primary procedure in 47 cases, and as a secondary procedure in 2 cases. All patients underwent dacryocystography, and 41 patients underwent radionuclide dacryoscintigraphy before the surgery. Silicone tubes were left in place for about 6.2 months. The patency of the lacrimal passages was controlled with a clinical examination, nasolacrimal canal lavage, and dacryoscintigraphy. RESULTS: Patients were followed up for a mean period of 25.1 months after the removal of the tubes. The epiphora symptom disappeared and a successful drainage could be maintained in 43 out of 49 cases (87.7%). The obstruction rate found in the dacryoscintigraphy performed 15 days after extubation was 22.9%, while it was found to be 14.2% in the nasolacrimal canal lavage. CONCLUSION: ETDCR combined with BSTI proved to be an effective surgical method in chronic dacryocystitis. The sensitivity and specificity of the postoperative dacryoscintigraphy in determining the surgical success were lower than those of the nasolacrimal canal lavage.

Adult↗
PubMedDate not supplied

Menstrual cycle-dependent changes in visual field analysis of healthy women.

PURPOSE: To determine the effect of menstrual cycle phases on the visual field analysis of healthy females. MATERIAL AND METHODS: One randomly selected eye each of 59 healthy normally menstruating women, and of 54 men with no systemic and ocular problems, other than refractive error, were included in the study. Subjects underwent complete ocular examination, and standard achromatic perimetric (SAP) and short-wavelength automated perimetric (SWAP) analysis in both follicular (7th to 10th day of the cycle) and luteal phases (days 3-7 before the menstrual bleeding) of the menstrual cycle. Visual field analysis was performed using a Model 750 Humphrey Field Analyzer II (Humphrey Instruments Inc., San Leandro, Calif., USA) with full-threshold, central 30-2 program. Visual fields were divided into four regions as superior temporal, inferior temporal, superior nasal and inferior nasal, respectively. RESULTS: The mean age of female (n = 59) and the male subjects (n = 54) were 34.6 +/- 2.9 and 35.0 +/- 2.7 years, respectively (p = 0.49). SWAP tests demonstrated a significantly decreased mean MS value in the luteal phase (p < 0.05). However, it did not change significantly with SAP tests. Regional MS values of both SAP and SWAP tests were not different in both phases of the menstrual cycle (all p values >0.05). Mean perimetric test durations obtained with both SAP and SWAP were not different throughout the menstrual cycle (both p values >0.05). CONCLUSION: Clinicians should verify menstrual status when evaluating a suspected loss of visual field sensitivity in menstruating women. The findings of the present study suggest that the SWAP test may be more sensitive to determine subtle sex hormone-dependent changes in visual field analysis of healthy women.

Adult↗
PubMedDate not supplied

Effect of pregnancy on intraobserver and intertechnique agreement in intraocular pressure measurements.

AIM: To evaluate the effect of pregnancy on intraobserver and intertechnique agreement for intraocular pressure (IOP) measurements. MATERIAL AND METHODS: Right eyes of 88 healthy women who were likely to become pregnant and of 94 healthy age-matched females were included in the study. Complete ocular examinations were performed on each eye. IOP measurements were obtained by Goldmann, Schiotz and non-contact tonometers (NCT) during 3-week exam periods before (within 6 weeks of conception) and during pregnancy (first, second and third trimesters) for pregnant cases, and in similar time intervals for control subjects. In each exam period, three readings with each of three separate tonometers were obtained, at least 1 day apart. Intraobserver and intertechnique agreements for IOP measurements were assessed. RESULTS: The mean visual acuity, keratometry and refractive error of both control and pregnant subjects did not change significantly during the study (all p values >0.01). In late pregnancy, pregnant cases demonstrated significant decreases in IOP measurements obtained with each of the three tonometers, and in intraobserver agreement with Goldmann and Schiotz tonometers (all p values <0.01). Intertechnique agreement of both Goldmann and Schiotz tonometers with NCT decreased significantly in the third trimester. Both intraobserver and intertechnique agreement in IOP measurements of control subjects were not found to change significantly during the study (all p values >0.01). CONCLUSION: IOP significantly decreased in the third trimester of pregnancy. Perfect intraobserver agreement in IOP readings of pregnant subjects was obtained with NCT. This may suggest that NCT is a viable option for IOP measurements during the follow-up of pregnant patients at risk for glaucoma.

Adult↗