Nilgun Yildirim

Reproducibility and tolerability of the ICare rebound tonometer in school children.

PurposeTo establish the intraobserver and interobserver reliability of the rebound tonometer (RBT) in healthy schoolchildren and to test patient tolerance in an unanesthetized eye. Subjects and MethodsTo examine the reproducibility of the RBT, 2 experienced ophthalmologists undertook 3 consecutive intraocular pressure (IOP) measurements with the RBT without an anesthetic in 304 eyes of 152 healthy schoolchildren. Any pain or discomfort experienced by the children was recorded. Intraobserver and interobserver reliabilities were established by calculating correlation coefficients (r). ResultsOf the 152 patients, 78 (51.3%) were males and 74 (48.7%) were females. The mean patient age was 11.2±2.6 years (range: 7 to 15 y). Mean IOP values obtained by examiners 1 and 2 were 16.48±2.82 mm Hg and 17.27±3.27 mm Hg for the right eyes and 17.15±3.36 mm Hg and 17.06±3.21 mm Hg for the left eyes. Intraobserver correlation coefficients for examiner 1 were 0.970 for the right eyes and 0.974 for the left eyes. For examiner 2, intraobserver correlation coefficients were 0.963 for the right eyes and 0.970 for the left eyes. The interobserver correlation coefficients were 0.798 for the right eyes and 0.858 for the left eyes (all P<0.0001). With the RBT, 98.6% of the subjects felt no pain and/or discomfort. ConclusionsMeasurement of IOP with the RBT is a highly reproducible method in schoolchildren showing high intraobserver and interobserver correlation and it seems to be very comfortable when performing IOP measurements in schoolchildren without an anesthetic.

Long-Term Results of Bare Sclera, Limbal-Conjunctival Autograft and Amniotic Membrane Graft Techniques in Primary Pterygium Excisions

Purpose: To compare the long-term follow-up results of the bare sclera technique (BST), limbal-conjunctival autograft technique (LCAT) and amniotic membrane graft technique (AMGT) in primary pterygium excisions. Materials and Methods: In this study, 48 eyes of 48 patients who underwent pterygium surgery using BST (group 1), 63 eyes of 63 patients who underwent pterygium surgery using LCAT (group 2) and 52 eyes of 52 patients who underwent pterygium surgery using AMGT (group 3) were compared with respect to corneal epithelialization, recurrence and complication of the procedures. The mean ages of the groups were 47.88 ± 14.21 years in group 1, 49.63 ± 14.42 years in group 2 and 47.92 ± 15.52 years in group 3. Patients were followed up to 72.39 ± 11.03 months in group 1, 69.91 ± 12.41 months in group 2 and 61.43 ± 9.83 months in group 3. Results: Postoperative corneal epithelialization was completed in 5.62 ± 1.74 days in group 1, 4.33 ± 0.91 days in group 2 and 4.79 ± 1.39 days in group 3. Corneal epithelialization time was earlier in group 2 than in groups 1 (p < 0.01) and 3 (p < 0.05). Recurrences were detected in 19 eyes (39.58%) in group 1, 11 eyes (14.29%) in group 2 and 12 eyes (23.08%) in group 3. The recurrence rate was significantly lower in group 2 than in groups 1 and 3 (p < 0.001). Postoperative complications were not seen in any of the groups. Graft retraction and necrosis were not detected in the LCAT and AMGT groups during the follow-up period. Conclusions: LCAT was found to be a more effective procedure than BST and AMGT, with decreased recurrence rates after pterygium excision. Limbal-conjunctival autograft seems to be a useful treatment in pterygium surgery due to higher success rates and lower recurrence rates. Amniotic membrane grafts may be an alternative surgical technique for pterygium treatment for patients with or without glaucoma who might need glaucoma surgery in the future.

Measurement of angle kappa with synoptophore and Orbscan II in a normal population.

PURPOSE To obtain normative values of angle kappa in a normal population by synoptophore and Orbscan II and to compare the reliability of these devices. METHODS Three hundred consecutive healthy individuals were enrolled in the study. A complete orthoptic and ophthalmologic examination was performed. Synoptophore and Orbscan II corneal topography were used to measure angle kappa. To evaluate the association of the angle kappa and refraction measures, individuals were further classified according to the degree of myopia and hyperopia. The spherical equivalent error measures were grouped into six categories: > or = -3.00 diopters (D); -2.75 to -1.50 D; -1.25 to -0.50 D; +0.50 to +1.25 D; +1.50 to +2.75 D; and > or = +3.00 D. Paired t test and Pearsons correlation test were used for statistical analysis. RESULTS The mean age of the individuals was 28.74 +/- 1.63 years (range: 20 to 40 years). The angle kappa values obtained by synoptophore and Orbscan II were normally distributed. In the myopic group, angle kappa values decreased significantly towards negative refractive errors. In contrast, a correlation existed between large positive angles and positive refractive errors in the hyperopic group. Angle kappa values obtained by Orbscan II were significantly higher in all groups when compared to synoptophore (P < .0001). A significant correlation was noted between synoptophore and Orbscan II measurements (r = 0.932, P < .0001). CONCLUSIONS A significant correlation exists between positive refractive errors and large positive angle kappa values. Refractive surgeons must take into account angle kappa, especially in hyperopic patients, to avoid complications related to decentration of the ablation zone.

Comparison of the rebound tonometer with the Goldmann applanation tonometer in glaucoma patients

Purpose:  To determine the agreement between the measurement of intraocular pressure (IOP) by the rebound tonometer (RBT) and by the Goldmann applanation tonometer (GAT) and to find out the effect of central corneal thickness (CCT) values on IOP measurements in glaucoma patients.

A comparative study between diode laser cyclophotocoagulation and the Ahmed glaucoma valve implant in neovascular glaucoma: a long-term follow-up.

BackgroundTo compare the efficacy, safety, and long-term results of intraocular pressure (IOP) reduction by diode laser contact cyclophotocoagulation (DCPC) and Ahmed glaucoma valve (AGV) implant in cases of neovascular glaucoma. MethodsA total of 66 eyes of 66 patients with neovascular glaucoma were prospectively assigned to either DCPC or AGV implantation. All patients underwent a baseline complete ophthalmologic examination and IOP measurement by Goldmann applanation tonometry before and after 1,3, 6, 12, and 24 months follow-up. Complications and the number of medications were recorded. ResultsMean age of the patients was 60.0±11.7 years (range: 20 to 85) in the DCPC group and 57.2±10.3 years (range: 20 to 85) in the AGV group. The preoperative IOP was 43.4±11.9 mm Hg and 43.3±7.4 mm Hg for the DCPC and AGV group, respectively (P>0.05). The postoperative IOP was 16.5±11.3 mm Hg and 22.09±7.6 mm Hg for the DCPC and AGV groups, respectively (P>0.05) at the last visit. Kaplan-Meier survival analysis showed a probability of success at 24 months of 61.18% and 59.26% for the DCPC and AGV groups (P>0.05). All the patients had a visual acuity of hand movement or worse preoperatively. Visual acuity decreased in 6 eyes (24%) in the DCPC group and 9 eyes (27%) in AGV group. Complications included anterior segment inflammation in 5 eyes (20%), neurotrophic keratitis in 2 eyes (8%), and hypotony in 3 eyes (15%) in the DCPC group and hyphema in 5 eyes (15%) and tube occlusion in 3 eyes (9%) in AGV group. ConclusionsThere was no significant difference in the success rate between the DCPC and AGV implantation in neovascular glaucoma treatment. However, DCPC is less time consuming and easier method for lowering IOP in patients with neovascular glaucoma.

The influence of central corneal thickness and corneal curvature on intraocular pressure measured by tono-pen and rebound tonometer in children.

PurposeTo find out the effect of central corneal thickness (CCT) and radius of the corneal curvature on intraocular pressure (IOP) measurements using rebound tonometer (RBT) and Tono-Pen in healthy schoolchildren. MethodsIOP was measured with Tono-Pen and RBT, respectively, in 165 healthy schoolchildren with a mean age 9.8±3.1 (range: 7 to 12 y) years. Corneal radius of curvature (in mm) was determined using a keratometer before CCT and IOP measurements. CCT was measured using an ultrasonic pachymeter after all IOP determinations had been made. The effect of CCT, radius of the corneal curvature, and sex on measured IOP was evaluated by linear regression analysis. ResultsThe mean IOP readings were 17.47±2.7 mm Hg using Tono-Pen, and 16.81±3.1 mm Hg using RBT. Tono-Pen measured IOP values slightly greater than that of RBT (P=0.006). Mean CCT was found to be 561.37±33 μm. A significant association between measured IOP and CCT was found with each device (r=0.220 for the Tono-Pen, r=0.373 for the RBT; P=0.006 for the Tono-Pen and P<0.0001 for the RBT). The IOP increased 2.2 and 3.7 mm Hg for every 100-μm increase in CCT for the Tono-Pen and the RBT, respectively. The relation between IOP and CCT was not different for boys and girls. Mean radius of the corneal curvature readings was 7.68±0.41 mm (42.75±1.37 D) for both sexes. There was no significant relationship between either the mean corneal curvature readings, or CCT and IOP (r=0.02; P=0.4 for CCT and r=0.01; P=0.5 for IOP). ConclusionsBoth the Tono-Pen and RBT have a systematic error in IOP readings caused by its dependence on CCT. The CCT measurements should be considered to ensure proper interpretation of IOP measurements in children, like in adults. The corneal radius of curvature had no significant effect on measured IOP with each device.

Der Effekt der Levodopatherapie auf das visuell evozierte Potential und die Sehschärfe in der Amblyopie

Amblyopia represents the most common form of visual impairment in children, affecting approximately 2% of the population. To determine the efficacy of the dopamine agonist levodopa for childhood amblyopia, a double-masked, placebo-controlled randomised study was performed on 32 amblyopic children with central fixation between 4 and 17 years. Subjects received 2 mg/kg levodopa benzeraside or placebo 3 times per day over a 1 week period. Estimates of visual acuity for each eye (Snellen visual acuity) were obtained, and pattern-shift visually evoked potentials (VEP) were examined by an opthalmologist and a neurologist. At the end of the dosing regimens, the levodopa group was significantly improved in visual acuity by 1.4 lines and pattern VEP amplitudes. No changes could be detected after placebo administration. One week after the termination of the treatment, Snellen line acuity and pattern VEP amplitude were decreased to pretreatment levels. The transient effect of levodopa points to a long-term treatment with the substance. Our results should therefore encourage further long-term clinical trials investigating the therapeutic potential of levodopa in amblyopia.

The reliability of central corneal thickness measurements by ultrasound and by Orbscan system in schoolchildren.

Purpose: To compare the central corneal thickness measurements obtained by ultrasound (US) pachymetry and the Orbscan II system in healthy schoolchildren. Methods: A total of 356 schoolchildren aged 7 to 12 years underwent central cornal thickness (CCT) measurement with Orbscan II and ultrasonic pachymetry. All eyes were examined first with the Orbscan II and then by US pachymetry. The mean of the difference, standard deviation (SD), and 95% limits of agreement, with and without applying the acoustic correction factor, were determined. The differences between the devices in measuring mean CCT were calculated with paired-sample t test. Pearson correlation test was used to determine the correlation between variables. p < 0.05 was considered to be statistically significant. Linear regression analysis was used to quantify the correlation between the two methods. Results: Orbscan II measurements were significantly higher than US pachymetry measurements without applying the manufacturer-recommended acoustic correction factor (0.92) correction (580.39 ± 37 μm and 562.95 ± 32 μm, respectively) (p < 0.0001). When this acoustic correction factor was applied, the Orbscan II measurements demonstrated significantly lower results when compared with those of US pachymetry (533.96 ± 34 μm and 562.95 ± 32 μm, respectively) (p < 0.0001). The linear regression analysis lines showed approximately 45-degree slope indicating a strong correlation between these methods (US pachymetry = 145.71 + 0.72 × Orbscan II value without acoustic correction factor (μm), r = 0.89, p < 0.0001). There was a high degree of variability in differences between the 2 devices in individual subjects. The range was between 25 to −55 μm without the acoustic correction factor and 67 to −5 μm with the acoustic correction factor. Conclusions: Although US pachymetry and Orbscan II demonstrated a strong linear correlation, there was a high degree of variability in differences between the two devices in individual subjects who participated.

Two-year interval changes in Orbscan II topography in eyes with keratoconus

PURPOSE: To define topographic characteristics and quantitatively document changes in corneal topography parameters in relation to the progression of keratoconus over time using the Orbscan II topography system (Bausch & Lomb). SETTING: Eskisehir Osmangazi University Medical School, Department of Ophthalmology, Meselik, Eskisehir, Turkey. METHODS: This study comprised 79 eyes (79 patients) with keratoconus who had Orbscan II topography examinations at least twice with a mean interval of 24 months ± 3.2 (SD). Topographic parameters including location radius, elevation compared to a best‐fit sphere, pachymetry, mean tangential curvature, and mean spheric curvature were evaluated with special reference to the central point of the cornea, the apex, and the thinnest point. The change in each parameter was calculated using the paired t test. RESULTS: The mean patient age was 32.4 ± 15.2 years. The increase in apex elevation (mean: 0.056 ± 0.033 mm baseline versus 0.069 ± 0.037 follow‐up) (P<.02) and displacement of the location of the apex were statistically significant. The mean thinnest‐point pachymetry decreased from 369 ± 53 μm at baseline to 343 ± 61 μm at follow‐up (P = .03). The mean simulated keratometry minimum value was 48.21 ± 5.5 diopters (D) and 54.09 ± 6.2 D, respectively, a statistically significant increase (P = .02). The mean radius, mean elevation, mean tangential, and mean spheric curvatures of the apex did not change significantly. CONCLUSION: The Orbscan II topography system provided useful and detailed numerical information on keratoconic corneas and documented their progression quantitatively by serial topographic analysis.

Lenstar versus ultrasound for ocular biometry in a pediatric population.

Purpose. To compare the central corneal thickness (CCT), axial length (AL), anterior chamber depth (ACD), and lens thickness (LT) measured with Lenstar with those obtained with ultrasound pachymetry and A-scan contact ultrasound (ASU) in children. Methods. ODs of 565 school children were included. All measurements were obtained 30 min after instilling 1% tropicamide. For each instrument, three consecutive measurements per each child were performed. Initially, examiner 1 performed measurements with Lenstar to obtain CCT, AL, ACD, and LT. Later, examiner 2 performed measurements with corneal pachymetry to obtain CCT. Finally, ASU was used by examiner 2 to obtain AL, ACD, and LT. Four parameters obtained with Lenstar were compared with those obtained with pachymetry and ASU using Pearson correlation coefficients (r) and Bland-Altman analyses. Result. Lenstar measurements were obtained in 557 of 565 subjects(mean age; 10.48 ± 2.11 years, mean spherical equivalent of the ODs; +0.47 ± 1.18 diopters) whereas ASU and pachymetry could be performed in 530 of 565. Four hundred seventy-nine subjects were statistically assessed after 41 subjects were extracted as outliers from 530 subjects in whom all instruments could be performed. Mean difference between pachymetry and Lenstar was 13.20 ± 13.13 &mgr;m [95% confidence interval (CI): 12.01 to 14.37]. Mean difference between ASU and Lenstar was −0.72 ± 0.35 mm (95% CI: −0.75 to −0.69) for AL, −0.27 ± 0.32 mm (95% CI: −0.30 to −0.24) for ACD, and 0.24 ± 0.28 mm (95% CI: 0.22 to 0.27) for LT. R values were 0.912 (p < 0.001), 0.904 (p < 0.001), 0.487 (p < 0.001), 0.369 (p < 0.001) for CCT, AL, ACD, and LT respectively. Conclusions. AL and ACD were found to be greater with Lenstar, whereas CCT and LT measures were smaller. It is concluded that there was agreement between instruments for CCT and ACD, because the small differences between measures were clinically insignificant. AL and LT values cannot be used interchangeably. If these differences are considered, Lenstar can replace ASU and pachymetry for the majority of children.