Retinal nerve fiber layer and ganglion cell layer thickness in patients receiving systemic isotretinoin therapy.

To evaluate the effect of oral isotretinoin therapy on retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) thickness by spectral domain optical coherence tomography (OCT). This prospective study included newly diagnosed nodulocystic acne patients about to receive isotretinoin treatment. Macular average GCL thickness and peripapillary average, temporal, nasal, inferior, and superior quadrant RNFL thickness were measured by OCT before and after isotretinoin treatment. Pre- and post-treatment measurements were compared with paired t test. Fifty-six eyes of 28 patients were included. The mean duration of the treatment was 6.5 ± 1.3 months. The mean average GCL thickness was 90.04 ± 5.87 (80-96) µm at baseline and 90.75 ± 6.34 (81-96) µm after treatment. The mean average RNFL thickness was 93.25 ± 6.06 µm (84-107) before treatment and 93.05 ± 5.54 µm (82-106) after treatment. There were no statistically significant differences between pre- and post-treatment values (all p > 0.05). A 6-month course of systemic isotretinoin therapy seems to have no unfavorable effect on retinal ganglion cells; however, larger studies with longer follow-up periods are needed to be conclusive.

Formaldehyde-induced keratopathy after strabismus surgery.

We report on a patient who developed corneal haze and permanent ptosis after strabismus surgery. Formaldehyde-disinfected sodium hyaluronate which was used to protect the corneal epithelium during surgery was thought to have induced keratopathy and other findings. To our knowledge, this is the first report of corneal haze formation together with ptosis secondary to formaldehyde toxicity as a complication of strabismus surgery.

Neutrophil-to-Lymphocyte Ratio Increases in Patients With Dry Eye.

PURPOSE: To assess the neutrophil-to-lymphocyte ratio (NLR) as an indicator of inflammation in patients with non-Sjögren dry eye disease. METHODS: Serum NLR and C-reactive protein values were determined in 33 patients with dry eye and in 32 controls. The NLR was calculated by dividing the neutrophil count by the lymphocyte count. RESULTS: Characteristics of the dry eye and control groups were similar. The mean NLR value was 2.8 ± 1.4 (range: 1.1-6.1) in the dry eye group and 1.6 ± 0.7 (range: 0.8-2.8) in the control group (P = 0.002, t test). The mean C-reactive protein value was 0.6 ± 0.7 mg/dL (range: 0-2.3 mg/dL) in the dry eye group and 0.5 ± 0.6 mg/dL (range: 0-1.9 mg/dL) in the control group (P = 0.307, t test). CONCLUSIONS: The NLR values were found to be higher in patients with non-Sjögren dry eye than in controls. This result suggests that non-Sjögren dry eye disease may be associated with systemic inflammation or the NLR values may increase in local inflammatory ocular diseases.

Effect of axial length on retinal nerve fiber layer thickness in children.

PURPOSE: To investigate the effect of axial length on peripapillary retinal nerve fiber layer (RNFL) thickness in myopic, hyperopic, and emmetropic eyes in children by Cirrus HD spectral-domain optical coherence tomography (OCT). METHODS: Subjects were divided into 3 groups according to their refractive status: myopic (n = 36), emmetropic (n = 30), and hyperopic (n = 28) eyes. The RNFL thickness measurements were taken from the superior, inferior, nasal, and temporal quadrants in the peripapillary region by Cirrus HD OCT. Axial length was also determined for each patient. RESULTS: The myopic eyes had thinner average RNFL and RNFLs of temporal, superior, nasal, and inferior quadrants than the hyperopic eyes (p1<0.001, p2 = 0.004, p3 = 0.011, p4 = 0.006, p5 = 0.033, respectively). In addition, average peripapillary RNFL thickness and RNFL thicknesses of all quadrants had significant negative correlations with axial length. On the other hand, after applying modified Littmann formula for correction of magnification effect, the differences among the 3 groups disappeared (all p>0.05). CONCLUSIONS: We have shown that axial length and accordingly refractive status influenced peripapillary RNFL thickness measurements by Cirrus HD OCT in children. Therefore, to make a correct diagnosis of glaucoma or other optic neuropathies in children, either axial length-induced magnification effect should be corrected by ophthalmologists or the current Cirrus HD OCT database should be revised taking axial length into consideration.

Plasma homocysteine levels in dry eye patients.

PURPOSE: To compare plasma homocysteine levels between patients with dry eye disease and normal control subjects. METHODS: Plasma homocysteine (enzyme immunoassay), vitamin B12, and folate levels were determined in 38 patients with dry eye and in 38 controls. RESULTS: Characteristics of the dry eye and control groups were similar. The mean plasma homocysteine level was 16.38 ± 6.98 µmol/L in the dry eye group and 14.39 ± 5.11 µmol/L in the control group (P = 0.10, t test). Hyperhomocysteinemia was present in the 43.9% of the dry eye patients and 33.3% of the controls (P = 0.43, χ test). There were no statistical differences between dry eye and control groups regarding plasma vitamin B12 and folate levels (P = 0.72 and P = 0.69, respectively, t test). CONCLUSIONS: Plasma homocysteine levels in dry eye patients may be inadequate to give homocysteine a role in pathogenesis. However, in ocular diseases like glaucoma, plasma homocysteine levels are significantly higher, and associated dry eye disease may cause an additional increase in plasma homocysteine levels.

Peripapillary retinal nerve fiber layer thickness in children with iron deficiency anemia.

PURPOSE: To evaluate peripapillary retinal nerve fiber layer (RNFL) thickness in children with iron deficiency anemia (IDA) in comparison with healthy controls and to investigate the correlation between peripapillary RNFL thicknesses and the hematologic parameters in these subjects. METHODS: Forty eyes of 40 children with a diagnosis of IDA (anemic group) and 40 eyes of 40 age- and sex-matched healthy children (control group) were enrolled in this study. Peripapillary RNFL thickness measurements were performed using Cirrus HD optical coherence tomography (OCT). RESULTS: Mean age of each group was 11.3±2.7 years. Average RNFL and RNFLs of superior and inferior quadrants were significantly thinner in the anemic group than in the control group (p=0.006, p=0.005, and p=0.005, respectively). In addition, average peripapillary RNFL thickness and RNFL thicknesses of superior, inferior, and temporal quadrants were correlated with hemoglobin levels (r1=0.734, p1<0.001, r2=0.456, p2=0.005, r3=0.598, p3<0.001, r4=0.349, p4=0.037, respectively) in anemic group. CONCLUSIONS. We found that children with IDA had different peripapillary RNFL profile measured by Cirrus HD spectral-domain OCT. We caution ophthalmologists when they measure RNFL thickness in children to diagnose glaucoma or other neuro-ophthalmic disorders.

Evaluation of peripapillary retinal nerve fiber layer thickness in patients with vitamin B12 deficiency using spectral domain optical coherence tomography.

PURPOSE: To compare peripapillary retinal nerve fiber layer (RNFL) thicknesses measured by Cirrus HD optical coherence tomography (OCT) of patients with vitamin B12 deficiency with healthy controls and to evaluate the correlation between the peripapillary RNFL thickness and plasma vitamin B12 levels. MATERIALS AND METHODS: Forty-five patients (19 male and 26 female) with a diagnosis of vitamin B12 deficiency (patient group) and 45 age- and sex- matched healthy subjects (control group) were consecutively enrolled in this study. Average, temporal, nasal, inferior, and superior quadrant peripapillary RNFL thicknesses of each subject were obtained using the Cirrus HD OCT. Disc area (DA) and rim area (RA), central subfield thickness (CST), cube volume (CV), and cube average thickness (CAT) were also measured. RESULTS: Mean age of each group was 33.1 ± 6.5 years (range: 21-45 years). Mean plasma vitamin B12 level was 114.8 ± 34.0 pg/mL in the patient group and was 405.1 ± 20.0 pg/mL in the control group (p < 0.001). The patient and control groups were similar regarding axial length, plasma folate levels, DA, RA, CST, CV, CAT, and RNFL thicknesses in superior, nasal, and inferior quadrants. However, average RNFL and RNFL in temporal quadrant were significantly thinner in the patient group than in the control group (p = 0.013 and p < 0.001, respectively). In addition, temporal (r = 0.356, p = 0.001) and average (r = 0.212, p = 0.045) peripapillary RNFL thicknesses were correlated with plasma vitamin B12 levels. CONCLUSION: We have shown that, as in other non-glaucomatous optic neuropathies, temporal quadrant RNFL thickness was thinner in patients with vitamin B12 deficiency and it was correlated with plasma vitamin B12 levels. Further studies are warranted to clarify the clinical relevance of these findings and the effects of vitamin B12 replacement therapy.

Effect of pterygium surgery on tear osmolarity.

Purpose. To investigate changes of dry eye test results in patients who underwent pterygium surgery. Methods. Seventy-four patients who underwent primary pterygium surgery were enrolled in this study. At the baseline, 3-, 12-, and 18-month visits, measurements of tear osmolarity, BUT, and Schirmer test were performed. The patients were divided into 2 groups: Group 1, which consisted of patients in whom pterygium did not recur, and Group 2, which consisted of patients in whom pterygium recurred after surgery. Results. The patients in Group 1 had lower tear osmolarity levels after surgery than those at baseline (all P < 0.001). In Group 2 the tear osmolarity levels did not differ from baseline after 18 months (P = 0.057). The prevalence rates of dry eye syndrome (DES) were lower than that at baseline and 18 months after surgery in Group 1 (P = 0.002). In Group 2, the incidence of DES was lower after 3 months than at baseline (P = 0.03) but was similar to the baseline rate after 12 and 18 months (both P > 0.05). Conclusions. Anormal tear film function associated with pterygium. Pterygium excision improved tear osmolarity and tear film function. However, tear osmolarity deteriorated again with the recurrence of pterygium.