Comparison of ocular discomfort after three different epithelial debridement techniques for corneal collagen cross-linking in keratoconus treatment.

PURPOSE: To compare the severity and duration of ocular discomfort after three different epithelial debridement techniques for corneal collagen cross-linking in the treatment of keratoconus. METHODS: Fifty-five patients (65 eyes) known to have keratoconus were enrolled in this retrospective study. The eyes were divided into three groups based on the technique used for epithelial debridement for corneal collagen cross-linking procedure; excimer laser transepithelial phototherapeutic keratectomy was used in group 1 (18 eyes), alcohol-assisted epithelial removal was used in group 2 (27 eyes), and mechanical epithelial debridement was used in group 3 (20 eyes). Preoperative and postoperative (third month) best-corrected visual acuity (BCVA) using Snellen chart, objective refraction, and keratometry results were recorded. The results of the questionnaire obtained from the patient's medical records were reviewed regarding their subjective evaluation of postoperative symptoms including foreign body sensation, tearing, photophobia, and burning at the end of the first postoperative week. Paired-samples t test was used to compare preoperative and postoperative clinical findings. One-way analysis of variance (ANOVA) was used to analyze the differences between three independent groups. RESULTS: BCVA improved from 0.51 ± 0.27 to 0.58 ± 0.21 (p = 0.05). Objective mean spherical and cylindrical refraction decreased from -5.08 ± 2.78D to -4.46 ± 2.91D (p = 0.22) and from -3.45 ± 2.73D to -3.03 ± 1.97D (p = 0.25). Mean maximum keratometry reading (K max) decreased from 57.63 ± 4.73D to 56.13 ± 4.47D (p = 0.001). The mean score for foreign body sensation was the highest in group 3 (4.50 ± 0.53) and the lowest in group 1 (2.10 ± 1.85) (p = 0.01). The mean scores for tearing, photophobia, and burning sensation were comparable in three groups (p = 0.84, p = 0.13, and p = 0.61, respectively). The duration of photophobia was the shortest in group 1 (1.50 ± 2.37 days), followed by group 3 (2.00 ± 1.31 days) and group 2 (4.00 ± 1.83 days) (p = 0.04). CONCLUSIONS: The severity and duration of adverse subjective symptoms during the first postoperative week after corneal collagen cross-linking appear to be milder with epithelial debridement using excimer laser transepithelial technique compared with -assisted debridement and mechanical debridement.

The adverse effects of valproic acid on visual functions in the treatment of retinitis pigmentosa.

PURPOSE: To evaluate the efficacy and safety of valproic acid (VPA) treatment in patients with retinitis pigmentosa (RP). METHODS: A total of 48 eyes of 24 patients (13 males, 11 females) with RP prescribed VPA were included. The length of VPA treatment was 6-12 months (mean 9.4 months). Parameters evaluated were best-corrected visual acuity (BCVA) (logarithm of the minimum angle of resolution [logMAR]), visual field analyses (VFAs) with Humprey automated perimetry, multifocal electroretinography (ERG) with Roland-RETI scan, and VPA side effects. RESULTS: Mean age was 34.3 ± 10.3 years (range 18-56 years). Fifteen of the patients (30 eyes) had two ERG and VFA tracings, allowing comparison between baseline and follow-up (range 6-12 months). Mean BCVA before and after VPA therapy was 0.36 ± 0.38 and 0.36 ± 0.37 logMAR, respectively (P = 0.32). Quantitative perimetric indices including mean deviation and pattern standard deviation were not significantly changed after VPA therapy (P > 0.05). P1 amplitudes (in terms of nV/deg2 and mV) of ERG waves were significantly decreased in the rings 1, 3, and 4 after VPA therapy (P < 0.05). Regarding the N1 amplitudes, the only significant decrease was observed in area 1 (P = 0.03). In addition, N1 latency was significantly increased in area 3 after VPA therapy (P = 0.04). CONCLUSIONS: VPA therapy did not have any significant benefit on BCVA and VFA. In addition, it may be associated with decline in some ERG parameters. Therefore, physicians should avoid prescribing VPA for RP until its safety and efficacy are appropriately evaluated.

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.

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.

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.