Ali Bulent Cankaya

Effect of Pseudoexfoliation on Corneal Transparency.

Purpose: To perform a comparison of the corneal optical density (COD) parameters in eyes with pseudoexfoliation syndrome (PES) and age-matched controls. Methods: This study was designed as a prospective cross-sectional study. Pentacam HR-Scheimpflug imaging system was used to observe the COD of PES, normal fellow, and normal control eyes. Forty-two patients with unilateral PES and 40 age- and sex-matched normal subjects were included. Group 1 included eyes with PES, group 2 included the clinically unaffected fellow eyes, and group 3 included right eyes of healthy patients. Main outcome measures were densitometry values of the cornea. Results: There was no significant difference between groups in means of central corneal thickness (P > 0.05). Eyes of unilateral PES patients and eyes of controls differed in COD parameters. Mean total COD in group 1 eyes (21.9 ± 4.9) and group 2 eyes (21.95 ± 5.1) was higher than that in group 3 eyes (17.72 ± 4.7) (P < 0.0001). Conclusions: This research demonstrates that the presence of pseudoexfoliation material can cause decrease in the transparency of clear cornea.

The effect of contact lens usage on corneal biomechanical parameters in myopic patients.

Purpose: To determine and compare the corneal biomechanical properties in myopic patients who use contact lenses and those who do not use contact lenses. Methods: The study consisted of 56 myopic patients who used contact lenses (study group) and 123 myopic patients who did not use contact lenses (control group). Intraocular pressure (IOP) was measured with an ocular response analyzer (ORA) and a Goldmann applanation tonometer. Central corneal thickness was measured with an ultrasonic pachymeter. Axial length and anterior chamber depth measurements were acquired with contact ultrasound A-scan biometry. The differences in ORA parameters between study and control group participants were analyzed. Results: The mean corneal hysteresis in study and control groups was 10.1 ± 1.6 mm Hg (6.5–15.9 mm Hg) and 9.7 ± 1.5 mm Hg (6.3–14.2 mm Hg), respectively (P = 0.16). The mean corneal resistance factor was 10.4 ± 1.9 mm Hg (4.6–15.5 mm Hg) in the study group compared with 9.6 ± 1.9 mm Hg (5.1–15.0 mm Hg) in the control group. The difference for corneal resistance factor was statistically significant (P = 0.014). There was no significant difference in corneal-compensated IOP (P = 0.24). Mean Goldmann-correlated IOP was significantly higher in the study group than in control subjects (15.8 ± 3.2 vs. 14.7 ± 3.7 mm Hg) (P = 0.044). None of the corneal biomechanical parameters was significantly correlated to duration of contact lens usage in the study group. Conclusions: Our results suggest that ORA-generated parameters may be different in subjects with and without contact lens usage. Further longitudinal studies need to be performed to establish the relevance of our results.

Topographic differences between large and normal optic discs: a confocal scanning laser ophthalmoscopy study.

Purpose The aim of the study was to investigate the optic nerve head parameters of healthy macrodiscs to provide standard measurements for them to be the basis for future quantitative comparisons. Methods Sixty-nine subjects with macrodisc (disc area larger than 2.82 mm2) and 91 healthy controls (disc area between 1.16 and 2.82 mm2) were recruited. After a complete ophthalmic examination, confocal scanning laser ophthalmoscopy was performed in all participants. The stereometric parameters of confocal scanning laser ophthalmoscopy examination and the proportion of subjects classified as normal, borderline, and glaucomatous by the Moorfield Regression Analysis were compared between groups. Results A total of 160 subjects were included in the study. The average disc sizes in the control and macrodisc groups were 2.14±0.33 mm2 and 3.36±0.36 mm2, respectively. Cup area (p<0.001), rim area (p=0.01), cup volume (p<0.001), cup/disc area ratio (p<0.001), linear cup/disc ratio (p<0.001), mean cup depth (p<0.001), maximum cup depth (p<0.001), and cup shape measure (p<0.001) differed significantly between the 2 groups. The parameters of the optic nerve head which did not differ significantly between groups were rim volume (p=0.17) and height variation contour (p=0.88). A significantly higher number of eyes were erroneously identified as abnormal (15.1% vs 79.4%) by Moorfield Regression Analysis in the macrodisc group (p<0.001). Conclusions Rim volume and height variation contour were the only optic nerve head topographic parameters that were similar in eyes with large and normal disc sizes. They seem to be promising parameters in the evaluation and comparison of the optic nerve head of subjects with macrodisc.

Changes of total antioxidant capacity and total oxidant status of aqueous humor in diabetes patients and correlations with diabetic retinopathy

AIM To measure changes of total oxidant status (TOS) and total antioxidant capacity (TAC) of aqueous humor (AH) in diabetic retinopathy (DR) patients, and to determine if there were any differences in TOS and TAC of AH in diabetic patients without retinopathy compared with non-diabetic patients. METHODS One hundred and three eyes of 103 patients who were enrolled for cataract surgery were included in this study. Patients were grouped according to presence of diabetes and stage of DR. Prior to cataract surgery, 0.1mL to 0.2mL of AH was aspirated and analyzed for TAC and TOS level using a colorimetric method. RESULTS TOS levels were highest among proliferative diabetic retinopathy (PDR) patients and lowest in patients with only cataracts. Results were statistically significant between all groups (P<0.05). Whereas result between diabetic without retinopathy patients and non-proliferative diabetic retinopathy (NPDR) patients was not statistically significant (P=0.757). TAC levels were highest in patients with only cataract and lowest among PDR patients and results were statistically significant between all groups (P<0.05). CONCLUSION Aqueous humor TAC levels are low in diabetic patients and reduced further in DR patients, TOS levels are increased in diabetic patients and this is exacerbated in DR patients.

Optic disc and retinal nerve fiber layer parameters of eyes with keratoconus.

BACKGROUND AND OBJECTIVE To evaluate optic nerve head (ONH) characteristics and retinal nerve fiber layer (RNFL) thickness measurements in patients with nonglaucomatous keratoconus. PATIENTS AND METHODS This was a cross-sectional, observational study in which 46 patients with keratoconus and 74 healthy subjects were included. Analysis of ONH and RNFL imaging were performed by confocal scanning laser ophthalmoscopy and optical coherence tomography, respectively. RESULTS Eyes with keratoconus had larger disc area (2.37 ± 0.5 vs 2.17 ± 0.36 mm(2)) (P = .013), larger cup area (0.65 ± 0.53 vs 0.49 ± 0.28 mm(2)) (P = .035) and deeper cup depths (for mean cup depth 0.24 ± 0.09 vs 0.20 ± 0.07 mm, P = .008 and for maximum cup depth 0.69 ± 0.27 vs 0.60 ± 0.17 mm, P = .037) than control group eyes. Height variation contour also differed in the two groups (P = .007) but RNFL measurements did not. CONCLUSION RNFL thickness between patients with keratoconus and healthy subjects seems to be more comparable than ONH parameters.

Scanning laser ophthalmoscopic parameters of eyes with exfoliation syndrome

PurposeTo evaluate optic nerve head (ONH) characteristics in patients with exfoliation syndrome (EXS).MethodsThis was a cross-sectional, observational study in which 73 eyes from 73 patients with EXS and 93 eyes from 93 age-matched healthy subjects who met the inclusion criteria were included. Topographic measurements of the ONH and peripapillary retinal nerve fiber layer (RNFL) thickness were performed by confocal scanning laser ophthalmoscopy, using a Heidelberg retina tomograph. Outcomes of interest were studied by Student t test and χ-squared test.ResultsEXS patients and age-matched controls did not differ in ONH parameters. Nevertheless, the mean cup depth and height variation contour values were higher in the normal subjects (P = 0.07, P = 0.056, respectively). Mean RNFL thickness was 0.22 ± 0.06 mm in the EXS group and 0.26 ± 0.06 mm in the control group, (P = 0.001). Likewise, the RNFL cross-sectional area was significantly lower in exfoliative eyes (1.16 ± 0.35 mm2) than in those of the control group (1.31 ± 0.33 mm2) (P = 0.006).ConclusionsNo significant differences in ONH parameters between EXS patients and age-matched healthy subjects were observed; however, RNFL measurements in eyes with EXS showed lower values.

Intravitreal Bevacizumab and Ranibizumab in the Treatment of Acute Central Serous Chorioretihopathy: A Single Center Retrospective Study

ABSTRACT Objectives: To evaluate and compare the anatomical and functional outcomes of patients with acute central serous chorioretinopathy (CSC) who did not receive any intervention or treatment with intravitreal bevacizumab or ranibizumab. Methods: A single-center retrospective comparative study. Seventy eyes of 70 patients were recruited for the study; 27 patients were only observed without any medication or intervention (observation group), 23 were treated with intravitreal bevacizumab (IVB group), and the remaining 20 were treated with intavitreal ranibizumab (IVR group). The best-corrected visual acuity (BCVA) and central macular thickness (CMT) obtained by spectral-domain optical coherence tomography were compared between the groups. Results: There were no significant differences between the groups with regard to age, sex, and follow-up periods (p>0.05). The mean time from baseline to initial complete resolution of subretinal fluid was 3.52±1.64 months in the observation group, 1.19±0.60 months in the IVB group, and 1.11±0.47 months in the IVR group; the resolution time was significantly longer in the observation group (p<0.001). While the CMT was significantly thicker in the observation group when compared to the IVB and IVR groups in the first month (p=0.001), it was similar between the groups in the third, sixth, and twelfth months (p>0.05). Additionally, pairwise comparisons of the IVB and IVR groups revealed that there were no significant differences between these groups regarding CMT at any follow-up time (p>0.05). Conclusions: Compared with observation alone, neither IVB nor IVR had a positive effect in terms of anatomical and functional outcomes for acute CSC. Although the resolution time of SRF is shorter by using ranibizumab, both the ranibizumab and bevacizumab could be effective in achieving rapid resolution of serous detachment in patients with acute CSC.

Oxidant/antioxidant balance in the aqueous humor of patients with glaucoma

AIM To evaluate total antioxidant status (TAS), total oxidant status (TOS), and the oxidative stress index (OSI) of the aqueous humor (AH) in patients with glaucoma. METHODS The prospective study was composed of a study group (n=31) and a control group (n=31). Fifteen patients in the study group were diagnosed with primary open angle glaucoma (POAG), and 16 patients were diagnosed with pseudoexfoliation glaucoma (PEG). The control group was composed of non-glaucomatous patients with cataracts. AH samples were collected and analyzed for TAS, TOS, and OSI levels. RESULTS Mean AH TAS level was significantly higher in patients with glaucoma than that in the control group (P<0.01). Mean TOS and OSI levels tended to increase in patients with glaucoma. No significant differences in TAS, TOS, or OSI levels were observed between patients with POAG and PEG. CONCLUSION High levels of TAS were observed in patients with glaucoma, which was likely a response to the increased oxidative stress observed in these patients.

Relationship between anterior segment and optic nerve head parameters in healthy subjects

PURPOSE To determine the relationship between anterior segment and optic nerve head (ONH) parameters. METHODS Two hundred healthy subjects were enrolled in this study. The par-ticipants underwent measurement of anterior segment parameters with a Pentacam Scheimpflug system and imaging of the optic disc with confocal scanning laser ophthalmoscopy. Pearsons correlation coefficient was calculated to assess the associations between ONH and anterior segment parameters. Multivariate regression analyses controlling for age and disc area as confounding factors were also conducted. RESULTS There were significant negative relationships between optic disc area and corneal thickness (p=0.03, r=-0.217) and volume (p=0.017, r=-0.239). Corneal refractive power was significantly correlated with cup area, rim area, rim volume, and cup/disc ratio (p<0.05 for all). An increase of 1 diopter in anterior corneal refractive power corresponded to a decrease of 0.022 in cup/disc ratio. Rim volume was negatively correlated with anterior chamber depth and anterior chamber volume (p<0.05 for both). A 1-mm3 increase in anterior chamber depth corresponded to a 0.154-mm3 decrease in rim volume. Mean and maximum cup depth measurements were not associated with any of the anterior segment parameters. CONCLUSIONS In nonglaucomatous eyes, the dimensions and shape of the ONH may be related to anterior segment morphology. Therefore, it may be helpful to take anterior segment parameters into consideration in evaluating the OHN.

Tear Film and Ocular Surface Evaluation in Gestational Diabetes Mellitus.

ABSTRACT Background: Dry eye syndrome is one of the complaints of diabetic patients. The aim of the present study was to evaluate the tear functions in pregnant women with gestational diabetes mellitus (GDM) using tests: Schirmer, tear break-up time (TBUT), and tear film osmolarity (TFO) tests and the Ocular Surface Disease Index score (OSDI). Methods: Pregnant women with GDM (Group 1, n=46) and healthy pregnant women (Group 2, n=36) were enrolled. Initially, all participants were asked to answer the OSDI and then they underwent a detailed ophthalmic examination including Schirmer, TBUT, and TFO tests. The individuals with ocular or systemic disorders that might affect the tear function tests and who were using topical medications were excluded. Results: The results of Schirmer, TBUT, TFO tests and OSDI scores were 11.20±4.93 mm, 5.59±2.16 sec, 309.65±14.80 mOsm/L, and 9.59 ± 9.69 in Group 1, respectively, and 12.33±5.33 mm, 5.67±2.68 sec, 308.36±16.00 mOsm/L, and 10.62±8.66 in Group 2, respectively. There was no significant difference in any of the tear function tests and OSDI scores between the study groups (p>0.05). Conclusion: GDM seems to have no negative effects on tear function tests. This may be due to a lack of duration of hyperglycemia long enough to affect the tear function tests of pregnant women.