Evaluation of the peripapillary retinal nerve fiber layer and ganglion cell-inner plexiform layer measurements in patients with iron deficiency anemia with optical coherence tomography

Objective: To evaluate the thickness of the peripapillary retinal fiber layer (RNFL) and macula ganglion cell-inner plexiform layer (GCL+) using optical coherence tomography (OCT) in patients with iron deficiency (ID) anemia.

Methods: This study included 73 eyes of 39 patients with ID anemia and 68 eyes of 34 age- and sex-matched healthy subjects. The measurements included the peripapillary RNFL thicknesses as average, 4 quadrant and 12 clock-hour (CH) based and macula GCL+ thicknesses as average and 6 quadrant based. All measurements were completed with Cirrus HD-OCT and the results were compared between the groups.

Results: A total of 73 eyes of 39 patients with ID anemia and 68 eyes of 34 healthy subjects were included to the study. Regarding peripapillary RNFL thicknesses of the study and control patients, the values of average and quadrants revealed no significant differences between the groups. In CH sectors comparison, peripapillary RNFL thicknesses were significantly decreased only in CH4 (68.7?±?14.5?μm in study versus 72.0?±?13.4?μm in control patients, p?=?0.049) and CH5 (93.4?±?20.0μm in study versus 102.2?±?20.1?μm in control patients, p?=?0.01) sectors. All measured quadrants were statistically similar, when macula GCL+ thicknesses were compared between the groups. When the correlations between peripapillary RNFL and macula GCL+ thicknesses and serum hemoglobin and ferritin levels of study and control patients were calculated, the only statistically significant parameter was the correlation of peripapillary RNFL thickness in CH10 sector with serum ferritin level (p?=?0.032, Spearman correlation coefficient: 0.369).

Conclusion: The study revealed that peripapillary RNFL is thinner in nasal-inferior quadrant in patients with ID anemia. The measurements of macula GCL+ thicknesses were similar between the groups. Analyzing the retinal layers using OCT may provide valuable information in neurodegenerative events.     

The effect of voluntary fasting and dehydration on posterior ocular structures

Purpose: Islamic Ramadan is the month of fasting, in which intake of food and drink is restricted from sunrise until sunset. The objective of the present study was to find out the effects of religious fasting on posterior ocular structures.

Materials and methods: In this prospective study, 34 eyes of 34 healthy volunteers with a mean age of 34.09?±?7.20?years were enrolled. Volunteers with any systemic disorder and eyes with pathology or previous surgery were excluded. One week before Ramadan (non-fasting period) and during Ramadan (fasting period) at the same hours (at 08:00 and 16:00?h), choroidal, macular, and retinal nerve fibre layer (RNFL) thicknesses were measured by spectral domain optical coherence tomography. Results were compared using paired sample t-test, and a p value <0.05 was accepted as statistically significant.

Results: The comparison of 16:00-h measurements significantly revealed lower values during fasting period when compared non-fasting period for choroidal thickness (non-fasting and fasting, respectively; subfoveal: 299.26?±?41.3 and 280.03?±?38.75 p?p?p?=?0.001) and paracentral macular thickness (superior: p?=?0.002, inferior: p?=?0.010, temporal: p?=?0.013, and nasal: p?=?0.016). By contrast, no significant differences were found in the central macular thickness between the fasting and non-fasting periods (p?=?0.735). Also, no statistically significant difference was noted for RNFL thickness at the different periods and time points.

Conclusion: Our results reveal that Islamic religious fasting is associated with statistically significant alterations in choroidal and paracentral macular thickness in healthy volunteers. However, more detailed investigations should be designed to evaluate whether fasting has a pivotal influence on pathological conditions.     

Ocular findings in coal miners diagnosed with pneumoconiosis

Objective: Our study aimed at evaluating ocular findings and structural changes in coal mine workers who were chronically exposed to coal mine dust and diagnosed with pneumoconiosis.

Methods: Ocular findings of 161 eyes of 81 patients diagnosed with pneumoconiosis who had previously worked or are currently working in coal mines were analyzed. Forty-six coal mine workers and sex matched healthy people (n?=?20) participated in the study. Workers who had early changes of pneumoconiosis were included in Group 1 (n?=?17), workers diagnosed with pneumoconiosis were included in Group 2 (n?=?29), and healthy subjects were included in Group 3 (n?=?20). Outcome measures were the difference in peripapillary retinal nerve fiber layer (RNFL) thickness, choroidal thickness (CT), central macular thickness (CMT) and tear function tests between the groups.

Results: RNFL thickness values in Group 1 and 2 were lower than in Group 3, the control group, in all quadrants except the temporal quadrant. However, there was no statistically significant difference in peripapillary RNFL thickness values in any quadrants among the three groups (p?>?0.05). Central subfoveal choroidal thickness and CMT measurements were thinner in Group 1 and 2 than in the control group. However, this difference among groups was not statistically significant (p?>?0.05). Mean schirmer's test result was 8.8?±?1.6?mm in group 1, 7.1?±?1.8?mm in Group 2 and 11.5?±?3.6?mm in the control group. Mean tear break up time (BUT) test result was 7.1?±?1.3?seconds (sec) in Group 1, 6.5?±?1.8?sec in Group 2 and 10.4?±?2.9?s in the control group. The Schirmer's test and BUT test results were both statistically significantly lower in coal mine workers (Group 1 and 2) compared to the control group. Group 1 and Group 2 did not show statistically significant difference in terms of Schirmer's test and BUT test results.

Discussion: The association between pneumoconiosis and coal mine dust contiguity is thought to be due to the effect of coal dust by producing chronic inflammation. In addition, there are several trace elements in coal dust which are toxic to vital tissues. In this study, ocular findings suggest that systemic levels of trace elements and chronic inflammation may not reach to a level that influences ocular structures. Nonetheless, tear functions seem to be affected in coal mine workers.

Conclusion: This study suggests that the systemic effect of coal mine dust in ocular structures is not evident. However, direct contact with coal mine and fume leads to a decrease in tear function tests.     

Effect of smoking on retina nerve fiber layer and ganglion cell-inner plexiform layer complex

Purpose: The aim of this study is to show the effects of smoking on retina layers, especially retina nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer complex (GCIPL).

Materials and methods: Participants smoking for more than 10 years at least 1 pack of cigarettes a day and a control group, both including participants between ages of 20 and 50 years with no other systemic or ocular diseases were studied. After normality tests, an independent sample t test was used to analyze the differences in age, sex, spherical equivalent (SE), intraocular pressure (IOP), axial length (AL), GCIPL and RNFL values between the groups.

Results: There were 44 participants in each group. There were 32 (62.5%) men and 12(37.5%) women in smokers and 36 (77.88%) men and 8 (22.22%) women in control group. Mean ages were 39.85?±?8.41 and 38.66?±?10.47 years, mean spherical equivalent (SE) values were ?0.15?±?0.4 and 0?±?0.29 dioptries in smokers and control groups, respectively. The IOP, AXL, GCIPL and RNFL values were 17.58?±?3.41?mmHg, 23.69?±?0.56?mm, 84.3?±?5.83?μm and 92.3?±?3.51?μm in the smokers group and 18.5?±?2.91?mmHg, 23.45?±?0.72?mm, 86.11?±?8.02?μm and 97.66?±?8.23?μm in the control group. The inferior, superior, nasal and temporal values of RNFL quadrants were 123.18?±?26.14, 117.05?±?5.51, 64.95?±?8.67 and 63.5?±?6.88?μm in the smokers group and 130.81?±?11.8, 123.55?±?11.03, 72.44?±?9.84 and 58.44?±?7.48?μm in the control group. There were no significant difference of age, sex, SE, IOP, AXL and GCIPL values between the smokers and control groups (p?>?0.05). The mean RNFL was significantly thinner in the smokers group compared to controls (p?=?0.03, independent t test). Inferior and superior quadrants of RNFL decreased in smokers group (p?=?0.01 and p?=?0.03, respectively) but temporal and nasal quadrants did not seem to be changed (p?=?0.96 and p?=?0.07, respectively).

Discussion: Smoking may affect RNFL thickness but not GCIPL.     

Assessment of ocular neurotoxicity in patients treated with systemic cancer chemotherapeutics

Purpose: Cisplatin and Paclitaxel are two chemotherapeutic agents known to produce neurotoxicity when used for cumulative dose regimens. In this study we aim to assess their toxicity in the optic nerve, and to evaluate the retinal nerve fibre layer (RNFL) thickness and visual field changes in lung cancer patients treated with Cisplatin and Paclitaxel.

Methods: Fifteen patients who were treated intravenously with 75?mg/m² cisplatin and 175?mg/m² paclitaxel every 3 weeks, up to a maximum of six courses, were enrolled in this prospective clinical trial. All patients underwent complete ophthalmological assessments before their treatments began, as well as three months after the completion of their treatments. The RNFL thickness measurements were performed using optical coherence tomography (OCT). Functional testing included the use of frequency-doubling technology (FDT) perimetry and the Humphrey visual field analyser (HFA). The main outcome measurements included the average RNFL thicknesses and visual field indices (mean deviation [MD] and pattern standard deviation [PSD]).

Results: The median age of the 15 patients (nine male and six female) was 63.49 years old (range: 53–77). The average RNFL thickness measurement during the baseline examination was 103.73?μm (range: 97–111). Three months after the cessation of treatment the RNFL thickness declined to 97.4?μm (range: 91–102). Statistical analysis showed a significant thinning between the two measurements (p?=?0.032). The MD and PSD values recorded by the HFA demonstrated no statistically significant changes 3 months after the cessation of treatment (p?>?0.207 and p?>?0.186, respectively). There were statistically significant decreases in both the MD (0.48 to ?1.13?dB) and PSD (2.13 to 0.65?dB) indices measured by the FDT perimetry (p?=?0.041 and p?=?0.025, respectively).

Conclusions: In our study, the systemic administration of Cisplatin and Paclitaxel affected the peripapillary RNFL thicknesses and visual field indices as revealed by FDT perimetry. OCT and FDT perimetry may be adjunctive tools for the screening of ocular toxicity in patients treated with these agents.     

Spectral domain-optical coherence tomographic findings in patients with ankylosing spondylitis under anti-tumor necrosis factor-alpha therapy

Objective: To evaluate the effect of tumor necrosis factor-alpha (TNF-α) blockade on the thickness of the peripapillary retinal nerve fiber layer (RNFL), the ganglion cell-inner plexiform layers (GCIPL), and the macula in ankylosing spondylitis (AS) patients under anti-TNF-α therapy.

Materials and methods: Twenty-one patients with AS received etanercept, or adalimumab, or infliximab for at least 6 months. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) levels, and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores were measured before and 6 months after the beginning of the treatment. Peripapillary RNFL, four regional fields (superior, inferior, nasal, and temporal), GCIPL, and macular thicknesses of the patients were analyzed by optical coherence tomography before the treatment, at 3 months and 6 months after the beginning of the treatment.

Results: The mean BASDAI, ESR, and CRP values were 5.2?±?1.5, 31.6?±?21.7, and 15.7?±?13.9, respectively, at the beginning of the treatment and 2.3?±?1.7, 21.3?±?15.1, and 10.1?±?10.3, respectively, 6 months after the beginning of treatment. There were significant differences among the mean BASDAI, ESR, and CRP values at the beginning of treatment and 6 months later (p?p?=?0.007, and p?=?0.009, respectively). There were no significant differences among peripapillary RNFL (p?=?0.24), four regional fields (p?=?0.98, p?=?0.23, p?=?0.09, p?=?0.47), GCIPL (p?=?0.25), or macular (p?=?0.33) thicknesses of the patients during anti-TNF-α treatment. In addition, the mean intraocular pressure levels throughout the follow-up did not show significant variation on repeated-measures ANOVA (p?=?0.77).

Conclusions: TNF-α blockade does not seem to influence RNFL, GCIPL, or macular thickness of patients with AS in the short term.     

The effect of cigarette smoking on retinal nerve fiber layer thickness in patients with migraine

Context: Migraine is a frequent and disabling chronic neurological condition with complex pathophysiology. Both cigarette smoking and migraine may cause damage to the optic nerve. Objective: The primary objective of this study was to investigate the effect of cigarette smoking on retinal nerve fiber layer (RNFL) thickness in patients with migraine.

Materials and methods: Eighty-four consecutive patients diagnosed with migraine (34 smokers and 50 nonsmokers) and 66 age- and gender-matched healthy non-smoker controls were enrolled for this observational cross-sectional study. RNFL thickness was measured using spectral-domain optical coherence tomography (OCT) and then RNFL thickness in patients with migraine who smoke was compared to nonsmoking patients with migraine and healthy subjects.

Results: The average, superior, nasal and inferior RNFL thicknesses were significantly thinner in patients with migraine compared to the control group (p?<?0.001, p?=?0.02, p?<?0.001 and p?=?0.04, respectively). The average and inferior RNFL thicknesses were significantly reduced in smoker patients with migraine compared to the nonsmokers (p?=?0.011, p?=?0.045, respectively). Nonsmoker patients with migraine had significantly thinner average and nasal RNFL thicknesses than the control group (p?=?0.001, p?=?0.001, respectively).

Conclusion: Cigarette smoking may cause significant RNFL thinning in patients with migraine. OCT may be a feasible technique for determination of smoking-induced ocular damage in patients with migraine.     

Retrospective analysis of the effect of aflibercept loading dose on the retinal vessel diameters in patients with treatment-naive neovascular AMD*

Background: To evaluate the effects of intravitreal aflibercept (IVA) on retinal vessel diameters in patients with neovascular age-related macular degeneration (AMD).

Design, setting, and participants: A retrospective study conducted at the Kutahya Dumlupinar University Faculty of Medicine included 15 eyes of 15 patients with treatment naive neovascular AMD.

Methods: All eyes received IVA injections once per month for 3?months; untreated contralateral eyes were used as controls. The central retinal artery equivalent (CRAE), central retinal vein equivalent (CRVE), and artery-vein ratio (AVR) values were measured using a computer-based program before the first IVA injection and 30?days after the first, second, and third injections. The main outcome measurements were the central macular thickness (CMT), best-corrected visual acuity (BCVA), choroidal thickness, CRAE, CRVE, and AVR.

Results: Significant vasoconstriction of the retinal arterioles was observed in all eyes treated with IVA when compared to baseline (p?=?0.009). However, no significant differences were found for CRVE or AVR throughout the study period in treated eyes. In the control group, all parameters measured during each visit were similar to baseline measurements (p?>?0.05). The mean BCVA significantly improved at the end of the loading dose of IVA, when compared to baseline (p?=?0.006). After the IVA injections, the mean CMT and choroidal thickness were significantly reduced at all visits, compared to baseline (p?Conclusions: The current study showed that IVA led to significant retinal arteriolar vasoconstriction and choroidal thinning, which may cause reduced retinal blood flow.     

Swept-source optical coherence tomography analysis in asthmatic children under inhaled corticosteroid therapy

Purpose: To evaluate retinal nerve fiber layer thickness (RNFLT), ganglion cell layer thickness (GCLT), subfoveal choroidal thickness (SFCT), and central retinal thickness (CRT) in asthmatic children who were under inhaled corticosteroid treatment by using Swept-Source Optical Coherence Tomography (SS-OCT).

Material and methods: Fifty-three children were prospectively analyzed in the study. Group 1 included 31 asthmatic children and group 2 included 22 healthy children. Asthmatic children received a dose 250?μg daily of inhaled fluticasone propionate (Flexotide, GlaxoSmithKline, Middlesex, UK). Allergy parameters including, exposure to smoke, eosinophil count, percentage of eosinophils, immunoglobuline (Ig) E levels, number of asthma attacks, number of sensitivity to allergens and follow-up time were recorded. The RNFLT, GCLT, SFCT, and CRT were analyzed with SS-OCT and the data were compared between the groups.

Results: There were 13 girls (41.9%) and 18 boys (58.1%) in group 1 and 13 girls (59.1%) and 9 boys (40.9%) in group 2 (p?=?0.22). The mean age was 9.3?±?2.2 years in group 1 and 9.9?±?1.5 years in group 2 (p?=?0.08). The mean CRT (239.26?±?34.56 µm versus 226.82?±?26.23 µm, p?=?0.22) and mean SFCT (273.97?±?40.95 µm versus 280.41?±?32.78 µm, p?=?0.54) did not significantly differ between the groups. The superior, inferior, and average RNFLT were significantly lower in group 1 than group 2 (p?p?p?Conclusions: The SS-OCT revealed that asthmatic children under inhaled corticosteroid treatment have lower RNFLT than healthy subjects.     

Effect of topiramate on choroidal thickness and anterior chamber parameters in the treatment of patients with migraine

Objective: To investigate the effects of topiramate on choroidal thickness and anterior chamber parameters using optical coherence tomography in the treatment of patients with migraine.

Methods: A total of 22 eyes of 22 adults (12 females, 10 males) diagnosed with migraine and scheduled to topiramate treatment for pain control were recruited in this prospective study. Choroidal thickness (CT), anterior chamber depth (ACD), anterior chamber angle (ACA), spherical refractive equivalent (SphEq) and intraocular pressure (IOP) measurements were recorded at baseline (prior the topiramate therapy), first and second month visits for the statistical analysis. One-way ANOVA with repeated measures test was used for the statistical evaluation.

Results: Mean age of the patients was 40.2?±?6.5?years. Mean CT at central fovea was 324?±?47?μm initially, 341?±?45?μm in the first month and 344?±?46?μm in the second month, thus first and second month measures were significantly higher than base values (p?p?=?0.001). Baseline ACD (3.66?±?0.22?mm) measures significantly decreased at the first month (3.63?±?0.22?mm) and second month (3.62?±?0.22?mm, p?=?0.009). Also, a significant reduction was detected in the first (36.2?±?4.9°) and second month (35.9?±?5.1°) ACA measures comparing with baseline (39.1?±?5.1°, p?=?0.05). A significant myopic shift was determined in the first and second month SphEq values (?0.08?±?0.6, ?0.10?±?0.6, respectively, p?=?0.05).

Conclusions: The study revealed increased CT and altered anterior chamber parameters and IOP due to topiramate therapy. Therefore, the patients using topiramate should be carefully monitored by an ophthalmologist considering the possible side effects.     

Follow up of retinal nerve fiber layer thickness with optic coherence tomography in patients receiving anti-tubercular treatment may reveal early optic neuropathy

Purpose: To evaluate the effect of anti-tubercular treatment on retinal nerve fiber layer (RNFL) thickness and the efficiency of optic coherence tomography (OCT) on early diagnosis of optic neuropathy.

Methods: Twenty patients diagnosed with either pulmonary or extra-pulmonary tuberculosis which were treated with anti-tubercular treatment (isoniazid (INH), rifampicin, ethambutol (ETM), and pyrazinamide) were enrolled in the study. RNFL thicknesses of the patients were measured via OCT, at baseline (before starting anti-tubercular treatment) and after the two-month treatment period. Standard ophthalmologic examinations were also performed.

Results: Compared to baseline values, after the two-month treatment period, thinning was detected in the right eye’s average and superior quadrant RNFLs (p?=?0.024 and p?=?0.006 respectively) and in the left eye’s average, superior quadrant, and inferior quadrant RNFLs (p?=?0.001, p?=?0.008, p?Conclusion: We displayed that patients receiving INH and ETM, which were the basic medicines of anti-tubercular treatment, experienced thinning in RNFL after the two-month treatment period. Patients receiving these drugs can be followed via OCT in terms of reduction in RNFL thicknesses for early diagnose of INH and ETM toxicity.     

The acute respiratory exposure by intratracheal instillation of Sprague–Dawley rats with diesel particulate matter induces retinal thickening

Context: Adverse health effects of ambient particulate matter (PM) have been demonstrated in humans, mostly in terms of respiratory and cardiovascular events. However, whether ambient particle could affect the eyes had not been fully revealed.

Objective: This study investigated the effect of acute respiratory exposure to PM on eyes.

Methods: Diesel exhaust product (DEP) of 200?mg/l was given endotracheally in Sprague–Dawley rats for 1?h (n?=?12) and compared to normal control (n?=?4). We enucleated eyes and histologically evaluated. Immunohistochemical stains for CD34 (Dako, Glostrup, Denmark, 1:50) and Ki-67 (DakoCytomation, Glostrup, Denmark, 1:150) were performed to evaluate new vessel formation and proliferation activity.

Results: After endotracheal DEP exposure, the thickness of retina was significantly increased to 258?±?96?μm in DEP group, while that of control was 113?±?9?μm (p?=?0.025). Among the retinal structure, inner plexiform, inner and outer nuclear and rod/cone cell layers were significantly thickened (p?=?0.00, 0.017, 0.004, 0.001, respectively). The outer plexiform layer of DEP group showed a tendency of thickening, but statistically insignificant. The afferent fiber and ganglion cell layer showed no thickness difference between two groups, but prominent capillaries with congestion were noted in DEP group. Neither neovascularization nor increased proliferation was demonstrated on CD34 and Ki-67 immunohistochemical staining in DEP group.

Conclusion: This study shows that the acute respiratory exposure of ambient PM increased retinal thickness, especially inner plexiform, inner and outer nuclear and rod/cone cell layers. We thought that increase of retinal thickness in DEP group resulted in hypoxia-induced edema.     

The effect of caffeine on choroidal thickness in young healthy subjects

Background: To investigate the effect of oral caffeine intake on choroidal thickness using optical coherence tomography (OCT).

Methods: Eighteen otherwise healthy caffeine users and 18 controls were enrolled. All participants underwent OCT scanning with high-speed and resolution spectral-domain OCT device (3D OCT 2000, Topcon, Japan) at baseline, and 1 and 3?h following 200-mg oral caffeine intake in the study and after oral placebo in the control group. The measurements were taken in the morning (10–12 am) to avoid diurnal fluctuation.

Results: The median choroidal thickness at the fovea prior to oral caffeine intake was 337.00 (IQR 83.75) μm, which decreased to 311.00 (IQR 79.25) μm at 1?h and 311.00 (IQR 75.00) μm at 3?h following oral caffeine intake (p?=?0.001, 0.002, respectively). The median choroidal thickness was also significantly decreased following oral caffeine intake at other five extrafoveal points (p?p?=?0.552, 0.704, respectively).

Conclusions: Caffeine causes a significant decrease in choroidal thickness following oral intake. This decrease might be a result of reduced ocular blood flow due to its vasoconstrictive effect.     

Direct and crossover effects of brinzolamide,betaxolol, and latanoprost on choroidal thickness

Purpose: To investigate the acute effects of brinzolamide, betaxolol, and latanoprost (drugs commonly used in the medical management of glaucoma) on choroidal thickness using enhanced depth imaging optical coherence tomography (EDI-OCT).

Methods: Ninety healthy volunteers were evaluated in this prospective study. Participants were randomly divided into 3 groups. Brinzolamide, betaxolol, and latanoprost were administered into the left eyes of the first group (n?=?30), second group (n?=?30), and third group (n?=?30), respectively, and artificial tear (Sodium hyaluronate) was instilled into the right eyes of all participants. Subfoveal choroidal thickness (SFCT) was measured using EDI-OCT before and 45?minutes after administration of the antiglaucomatous drops.

Results: SFCT revealed a significant increase in the left eye (administered antiglaucomatous drop) in the brinzolamide (p?=?0.001) and betaxolol groups (p?=?0.049) and a significant increase also in the right eye (administered artificial drop) in the brinzolamide (p?=?0.001) and betaxolol groups (p?=?0.001). However, SFCT did not reveal a significant increase in the left eye (p?=?0.213) or in the right eye (p?=?0.062) in the latanoprost group.

Conclusion: Brinzolamide and betaxolol caused an increase in SFCT, while latanoprost had no significant effect on SFCT.     

Acute effects of caffeine on choroidal thickness and ocular pulse amplitude

Objective: To explore ocular changes in healthy people after caffeine consumption.

Methods: This prospective observational study was carried out with students of the Turgut Özal University Medical Faculty from May 15 to 15 December 2014. Enrolled in the study were 17 healthy subjects (n?=?17 eyes), with a median age of 24 (IQR 1), ranging between 21 and 26 years. The control group (6 females, 11 males) aged between 23 and 28 (median 25 years [IQR 4.75]). For study, one eye from each participant was randomly selected. To obviate the effect of diurnal variations, tests were performed at the same time of the day (10:00?a.m.–12:00?p.m.). Each subject was given an ophthalmologic examination before the study to exclude those with undiagnosed ocular disease. Version 6.0 Cirrus high-definition optical coherence tomography (HD-OCT) (Carl Zeiss Meditec, Dublin, CA) was used to measure CT at the fovea, and 1500?μm nasal and 1500?μm temporal to the fovea. After baseline OCT measurements, participants were asked to have 200?mg oral caffeine intake or a placebo capsule (200?mg lactose powder). Two further OCT measurements were applied at the first and fourth hours of caffeine intake. All participants also had intraocular pressure (IOP) and ocular pulse amplitude (OPA) measurements recorded before, first and fourth hours of caffeine intake. IOP and OPA were measured using the dynamic contour tonometry (DCT) (Swiss Micro Technology AG, Port, Switzerland).

Results: The groups showed no significant difference by means of age, gender, spherical refraction and axial length (p?>?0.05). Baseline choroidal thickness measurements of the study and control group showed no significant difference. Oral caffeine intake caused a significant reduction in choroidal thickness compared with baseline, at all three measurement points, (p?<?0.05). There were no significant changes in IOP and OPA measurements compared with the baseline values (p?>?0.05). The choroidal thickness still continued to decrease for at least 4?h following caffeine intake; whereas, the difference between 1 and 4?h was not statistically significant (p?>?0.05). However, choroidal thicknesses, IOP and OPA values of the control group revealed no significant difference at all points when comparing measurements at baseline with 1 and 4?h after placebo intake (p?>?0.05).

Conclusions: We found no significant change in IOP and OPA following oral 200?mg caffeine intake, while CT significantly decreased, for at least 4?h.     

Optical coherence tomography findings in patients with alcohol use disorder and their relationship with clinical parameters

Abstract

Purpose: In our study, we aimed to investigate the ganglion cell-inner plexiform layer thickness (GCIPL), retinal nerve fibre layer thickness (RNFL), mean macular volume (MMV), central macular thickness (CMT), mean macular thickness (MMT), and choroidal thickness (CT) values with optical coherence tomography (OCT) in patients who are diagnosed with alcohol use disorder (AUD).

Materials and methods: The study included 43 patients who were diagnosed with AUD, and 43 healthy controls. Detailed biomicroscopic examinations of all the participants, visual acuity, intraocular pressure, anterior and posterior segment examinations, and then, OCT measurements were carried out.

Results: Although the measured values for RNFL in the superior and temporal quadrant are within normal limits, they were slightly higher compared to those in the control group (p values 0.127 and 0.191 for superior quadrant and temporal quadrant, respectively). The CT measurements in all quadrants were higher than the control group; however, these measurements were not statistically significant (p?>?0.05). When the relation between clinical features and OCT findings of the patients were examined, it was determined that the ages of the patients were statistically significantly and inversely correlated with the temporal CT and also the nasal and temporal quadrants of RNFL.

Conclusions: Our study is the first study that examines the retinal GCIPL and CT with OCT in patients who are diagnosed with AUD. In our results, it was determined that there were no statistically significant differences between the participants in terms of OCT parameters. Further studies with larger sampling groups evaluating neurotransmission findings may provide wider results.     

Retinal structural changes in patients receiving tamoxifen therapy by spectral-domain optical coherence tomography

Abstract

Purpose: To evaluate choroidal thickness, ganglion cell complex (GCC) and photoreceptor outer segment (PROS) length were measured in patients with breast cancer undergoing tamoxifen therapy, using spectral-domain optical coherence tomography (SD-OCT); results were compared with those for normal eyes.

Materials and methods: Forty-four patients with breast cancer, undergoing tamoxifen therapy, and 41 healthy controls were included in this prospective, comparative study. All participants underwent a complete ophthalmologic evaluation and SD-OCT. Subfoveal, nasal (nasal distance to fovea 500, 1000, 1500?μm), and temporal (temporal distance to fovea 500, 1000, 1500?μm) choroidal thickness measurements were performed using the enhanced depth imaging mode of SD-OCT. Using an Early Treatment Diagnostic Retinopathy Study (ETDRS) circle at the macular level, the automated retinal segmentation software was applied to determine the thickness of the GCC. PROS length was determined manually, as the distance from the inner surface of the ellipsoid zone to the inner surface of retina pigment epithelium.

Results: The mean choroidal thickness was statistically greater in the tamoxifen group than controls in all quadrants (p?<?0.001 for all quadrants). Of all tamoxifen users (44 eyes of 44 patients), 33 eyes (75%) had uncomplicated pachychoroid (UCP). Pachychoroid pigment epitheliopathy (PPE) was detected in five tamoxifen-group patients (11.3%). Patients with PPE in one eye had UCP in the fellow eye. Central serous chorioretinopathy findings were observed in one patient. Tamoxifen users had statistically lower GCC thickness in all inner rings of the ETDRS inlay and in the nasal outer ring only (p?=?0.027, 0.002, 0.002, 0.001, and 0.030, respectively). No statistically significant difference in mean subfoveal PROS length was found between the groups.

Conclusions: SD-OCT provides valuable information for identifying structural changes and evaluating ocular findings in patients receiving tamoxifen therapy. Increased choroidal thickness, PPE and thinning GCC were detected in tamoxifen users. These OCT findings may be an early indicator of retinal toxicity for patients undergoing tamoxifen therapy in the follow-up period.     

Effects of cigarette smoking on choroidal and retinal thickness and ocular pulse amplitude

Background: In our study, we aimed to show the effects of smoking on choroidal thickness and ocular pulse amplitude. It is known that the anatomy and physiologic functions of the choroid is important in ocular diseases like glaucoma and age-related macular degeneration. Choroidal thickness is measured by the spectral domain optical coherence tomography (SD-OCT). The ocular pulse amplitude (OPA) is the difference between the systolic and diastolic intraocular pressure (IOP) and it is an index of choroidal perfusion.

Design: This was a cross-sectional prospective observational study at the Turgut Ozal University Hospital setting.

Participants: The test subjects were divided into two groups: the smokers group which consisted in 24 participants (20 male, 4 female) and the control group with 22 participants (16 male, 6 female).

Methods: The participants underwent full ophthalmological examination including best-corrected visual acuity (BCVA), spherical equivalent (SE) values of refractive errors, intraocular pressure (IOP), ocular pulse amplitude (OPA), central corneal thickness (CCT), axial length (AL) and choroidal thickness. The IOP and the OPA were measured with the dynamic contour tonometer. The CCT and the AL were measured with the Nidek AL-Scan (Nidek Co., Ltd., Gamagori, Japan). The choroidal thickness was measured by the Cirrus high-definition optical coherence tomography (Cirrus Version 6.0; Carl Zeiss Meditec, Dublin, CA).

Results: Gender did not differ significantly between the groups (p?=?0.12). The age, SE, IOP, OPA, CCT and AL did not differ significantly in smokers and control groups (p?=?0.12, p?=?0.37, p?=?0.54, p?=?0.80, p?=?0.56 and p?=?0.82, respectively). The nasal, temporal, central retinal (p?=?021, p?=?021, p?=?0.11) and nasal, temporal, central choroidal thicknesses (p?=?0.80, p?=?0.39, p?=?0.75) did not differ significantly between smokers and control groups.

Conclusions: We could not find a significant difference in OPA, retinal and choroidal thicknesses between smokers and non smokers. Further studies including histopathological changes in larger groups are needed to show the effect of smoking on choroidal thickness especially in patients with ocular diseases like age-related macular degeneration.     

Evaluation of the effects on choroidal thickness of bimatoprost 0.03% versus a brinzolamide 1.0%/timolol maleate 0.5% fixed combination

Objective: To investigate the effects of two different medical treatment options on choroidal thickness (CT) in cases of open-angle glaucoma (OAG).

Methods: Sixty-seven eyes newly diagnosed with OAG and 52 healthy eyes constituting the control group were included in the study. Glaucomatous eyes were randomly divided into two subgroups; Group I was started on bimatoprost 0.03% and Group II on a brinzolamide 1.0%/timolol maleate 0.5% fixed combination (BTFC). Intraocular pressure (IOP), ocular pulse amplitude (OPA) and subfoveal CT measurements were performed in all eyes in the study before treatment and on weeks 2, 4 and 8 after treatment.

Results: Mean initial IOP values in groups I and II and the control group were 25.5?±?4.7, 25.1?±?5.2 and 16.1?±?2.9?mmHg, mean OPA values were 3.7?±?1, 3.6?±?1.4 and 2.4?±?0.6?mmHg and mean CT values were 269.4?±?83, 264.5?±?84.4 and 320.1?±?56.6?μm, respectively. Eight weeks after treatment, mean IOP values in Groups I and II and the control group were 18.3?±?2.6, 18.1?±?3.4 and 15.7?±?2.9?mmHg, mean OPA values were 2.9?±?1.2, 2.8?±?1.5 and 2.3?±?0.8?mmHg and mean CT values were 290.2?±?87.3, 271.8?±?82.5 and 319.3?±?56.8?μm, respectively. No significant difference was determined in terms of the decrease in IOP and OPA obtained after treatment in Group I and Group II. However, a significant difference was observed between the two groups in terms of choroidal thickening after treatment.

Conclusion: The use of topical ocular hypotensive medication in eyes with OAG results in an increase in CT. This increase is relatively greater with bimatoprost 0.03% therapy compared to BTFC.     

Effectiveness of a new tobramycin (0.3 % ) and dexamethasone (0.05 % ) formulation in the treatment of experimental Pseudomonas keratitis

ABSTRACT

Objective: To quantitatively determine, in a Pseudomonas keratitis model, the anti-inflammatory and bactericidal properties of a new formulation of tobramycin (0.3?%?) and dexamethasone (0.05?%?) that utilizes a xanthan gum vehicle.

Research methods: In a randomized and masked fashion, rabbit corneas (n?≥?16 eyes per group) were intrastromally injected with 10³ colony-forming units (CFU) of P. aeruginosa. Eyes were untreated or were administered a single drop every 15?min between 16 and 17?h postinfection (PI) and then a single drop every 30?min between 17 and 22?h PI, a total of 15 drops of either 0.1?%?dexamethasone and 0.3?%?tobramycin (TobraDex; Tdex) or a new formulation 0.3?%?tobramycin and 0.05?%?dexamethasone with xanthan gum (TobraDex ST; ST). Slit lamp examination scores (SLE?±?SEM) were derived from grading seven parameters at 22?h PI. Rabbits were sacrificed at 23?h PI and the log CFU?±?SEM per cornea was determined.

Results: Untreated eyes had SLE scores of 11.11?±?0.43 and had log CFU of 7.27?±?0.06. Eyes treated with Tdex, as compared to the untreated eyes, had significantly lower SLE scores (7.39?±?0.21, p?<?0.0001) and significantly fewer bacteria (6.32?±?0.29 log CFU, p?=?0.0213). Eyes treated with ST had a SLE score (6.56?±?0.19) that was significantly lower than both the untreated eyes (p?<?0.0001) and the eyes treated with Tdex (p?=?0.0124). Furthermore, eyes treated with ST had significantly fewer log CFU (5.78?±?0.30) than untreated eyes (p?=?0.0001) or eyes treated with Tdex (p?=?0.0434).

Conclusions: The ST formulation with xanthan gum demonstrated statistically superior anti-inflammatory and bactericidal properties as compared to Tdex.

Limitations: Variations in inoculation procedures produced limited eye-to-eye differences in the infection.