Orhan Ayar

Posterior corneal elevation and back difference corneal elevation in diagnosing forme fruste keratoconus in the fellow eyes of unilateral keratoconus patients

Purpose To evaluate posterior corneal elevation and back difference corneal elevation in patients with keratoconus in 1 eye and forme fruste keratoconus in the fellow eye. Setting Kudret Eye Hospital, Ankara, Turkey. Design Case‐control study. Methods This study retrospectively reviewed patients with keratoconus in 1 eye and forme fruste keratoconus in the fellow eye and eyes of normal subjects. All subjects were evaluated with a rotating Scheimpflug imaging system (Pentacam), including sagittal and tangential anterior curve analysis, keratometry, and posterior elevation. The back difference elevation values were extrapolated from the difference maps of the Belin‐Ambrosió enhanced ectasia display of the Scheimpflug system. The receiver operating characteristic (ROC) curves were analyzed to evaluate the sensitivity and specificity of the parameters. Results The corneal power, pachymetric progression index, and posterior corneal elevation (posterior elevation and back difference elevation) measurements were statistically significantly higher in eyes with keratoconus or forme fruste keratoconus than in eyes of normal control subjects (P<.05). Using ROC analysis, the area under the curve values of mean keratometry, steepest point on the tangential curve, minimum corneal thickness, pachymetric progression index, Ambrósio’s relational thickness, posterior elevation, and back difference elevation to distinguish forme fruste keratoconus from control subjects were 0.51, 0.84, 0.65, 0.81, 0.72, 0.68, and 0.76, respectively. Conclusions Back difference elevation was better than posterior elevation in diagnosing forme fruste keratoconus. However, as sole parameters, both had limited sensitivity and specificity to differentiate between forme fruste keratoconus eyes and normal control eyes. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Comparison of multimetric D index with keratometric, pachymetric, and posterior elevation parameters in diagnosing subclinical keratoconus in fellow eyes of asymmetric keratoconus patients

Purpose To compare the multimetric D index and other keratoconus‐screening parameters in patients with clinical keratoconus in 1 eye and subclinical keratoconus in the fellow eye. Setting Medipol University Hospital and Birinci Eye Hospital, Istanbul, Turkey. Design Retrospective case‐control study. Methods Patients with clinical keratoconus in 1 eye and subclinical keratoconus in the fellow eye and eyes of normal subjects were evaluated with a rotating Scheimpflug imaging system (Pentacam). Parameters included anterior curve analysis, keratometry (K) values, minimum corneal thickness, pachymetric progression index, Ambrósio relational thickness, posterior elevation, back difference elevation, and D‐index values. The receiver operating characteristic (ROC) curves were analyzed to evaluate the area under curve (AUC), sensitivity, and specificity of each parameter. Results Forty‐five patients and 67 normal subjects were evaluated. The pachymetric progression indices, posterior elevation, and the D‐index measurements were statistically significantly higher whereas corneal thickness and Ambrósio relational thickness measurements were significantly lower in eyes with keratoconus or subclinical keratoconus than in eyes of normal subjects (P < .05). Using the ROC analysis, the AUC values of the mean steep K, minimum corneal thickness, pachymetric progression index minimum, Ambrósio relational thickness maximum, posterior elevation, back difference elevation, and D index to distinguish between subclinical keratoconus from control subjects were 0.52, 0.64, 0.71, 0.72, 0.71, 0.76, and 0.83, respectively. Conclusion The new multimetric D index seems to be better than other single‐metric parameters in diagnosing keratoconus and subclinical keratoconus with good specificity. However, the sensitivity levels of all parameters were relatively limited in the diagnosis of subclinical keratoconus. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Topical cyclosporine A administration after pterygium surgery.

Purpose To evaluate the success rate of topical cyclosporine A (tCsA) (Restasis®, Allergan) in preventing the recurrence of pterygium excision and conjunctival flap rotation technique in patients applying to our clinic and diagnosed with pterygium. Methods A total of 56 eyes with primary pterygium in 56 patients were examined and operated with pterygium excision and conjunctival flap rotation technique between October 2008 and September 2009. A total of 26 eyes of these 56 patients were treated with tCsA (Restasis®, Allergan) for 6 months during the postoperative period and assigned as the treatment group. The other 30 eyes of 56 patients were assigned as the control group. The operated patients were followed up for approximately 11 months. Results The 2 groups were similar in age, sex, and pterygial size. The largest percentage of the patients were farmers (30.3%). The pterygium recurred in 8 (14.2%) of 56 patients; 2 of them were in the treatment group (7.7%) and 6 of them were in the control group (20.0%). There was not any complication threatening vision among operated patients. Recurrence rates between the control and treatment group were statistically significant (p<0.05). The complication and postoperative compliance rates were lower in the treatment group than the control group. The difference between preoperative and postoperative Schirmer I test results among the treatment and control group was statistically significant (p<0.05). The Schirmer I test results increased after tCsA treatment for patients assigned to the treatment group. Conclusions The results suggest that tCsA (Restasis®, Allergan) can be used safely and effectively after pterygium surgery to obtain lower rates of recurrence.

Change in tear film characteristics in visual display terminal users.

Purpose To evaluate changes in symptoms and tear film characteristics in young computer users. Methods Fifty-one computer users and 26 controls were evaluated at the beginning and the end of the working day. Subjects with ocular or systemic disease, history of ocular surgery, use of contact lenses or glasses with antireflective surfaces, and use of topical or systemic medications were excluded from the study. Computer use duration, Ocular Surface Disease Index (OSDI) questionnaire, tear osmolarity, Schirmer test, tear break-up time (TBUT), and ocular surface vital dye staining were performed prevocationally and postvocationally. Results The mean age was 31.2 ± 6.3 years in computer users and 33.7 ± 5.8 in controls. The mean reported computer use was 6.9 ± 2.7 hours/day in computer users and 0.4 ± 0.5 hours/day in controls. The mean prevocational and postvocational values in computer users for OSDI, osmolarity, TBUT, and Schirmer test were 23.2 ± 16.6 and 27.0 ± 17.6, 306.6 ± 14.9 and 311.0 ± 12.5 mOsm/L, 13.9 ± 4.0 and 13.2 ± 3.8 seconds, 22.7 ± 11.8 and 20.6 ± 12.5 mm, respectively. The vocational change was significant for all parameters in the computer user group but not in the control group. The osmolarity-based dry eye diagnosis was 27.4% in the computer users while it was 15.4% in the control group. Oxford score was only grade 1 in 5.9% of visual display terminal users and did not change at the end of the day. Conclusions Both symptoms and signs of dry eye increased significantly with computer use. Approximately 1 of every 3-4 computer users was found to have dry eye with higher tear osmolarity values.

Measurement of the anterior chamber angle according to quadrants and age groups using Pentacam Scheimpflug camera.

Purpose:This present study aims to investigate the changes in the anterior chamber angle width according to quadrants and age with Pentacam Scheimpflug rotating camera. Method:Both eyes of 110 healthy outpatients, selected randomly, were included in this prospective study between March 2009 and June 2009. The patients were divided into 3 age groups: group 1 (⩽20 y; n=80 eyes), group 2 (21 to 40 y; n=66 eyes), and group 3 (≥41 y; n=74 eyes). Angle widths of 12 points (0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, and 330 degrees) were measured in each eye. The angle width of the superior nasal quadrant (SNQ), superior temporal quadrant (STQ), inferior nasal quadrant, and inferior temporal quadrant were determined according to arithmetical mean of measurements. Results:No significant difference was observed between groups 1 and 2, in terms of the angle widths in all quadrants, for both right and left eyes. However, the angle widths in all quadrants were significantly lower in group 3 than in the other 2 groups (P<0.05). Intragroup analysis was performed to evaluate the differences between the angle widths in all quadrants for the right and left eyes. Among the patients in groups 1 and 3, no significant difference, in the terms of angle width, was found between the quadrants neither in the right nor in the left eye. In group 2, STQ was significantly narrower than the inferior quadrants in the right eye. However, no significant difference was found between the SNQ and the other quadrants. In addition, no significant difference was detected between the inferior quadrants in the right eye. In group 2, SNQ was significantly narrower than the inferior quadrants in the left eye. However, there was no significant difference between the STQ and the other quadrants. In addition, no significant difference was detected between the inferior quadrants in the left eye. Conclusions:This study is the first study that assessed the angle depth in different age groups in 4 quadrants with the highest number of measurements, and the outcomes show that the angle becomes narrower with time and except for the young adults there is no difference between the angle depths in quadrants.

The Effect of Pseudoexfoliation and Pseudoexfoliation Induced Dry Eye on Central Corneal Thickness

ABSTRACT Purpose/aim of the study: The aim of this study is to investigate the effect of pseudoexfoliation (PEX) and PEX-induced dry eye on central corneal thickness (CCT). Materials and methods: This cross-sectional study consists of total 270 eyes of 135 patients (67 females, 68 males) in total. After excluding the PEX (−) 32 eyes with PEX in the other eye, totally 130 eyes in PEX (−) group and 108 eyes in the PEX (+) group were included in the study. The PEX (+) group was regrouped as PEX syndrome (80 eyes of 50 patients) and PEX glaucoma (28 eyes of 20 patients). Results: In the PEX (−) group, the mean Schirmer test result was 12 ± 4 mm (4–25 mm), in the PEX syndrome group 10 ± 4 mm (4–22 mm), in the PEX glaucoma group 9 ± 3 mm (4–15 mm). The difference among the PEX (−) group, the PEX syndrome and the PEX glaucoma groups was statistically significant (p < 0.001, p < 0.001, respectively). In the PEX (−) group, the mean tear break up time test result was 11 ± 2 s (5–16 s), in the PEX syndrome group 8 ± 3 (3–16 s), in the PEX glaucoma group 8 ± 3 s (5–15 s). Mean CCT result was 544 µm in the PEX (−), 521 µm in the PEX syndrome group and 533 µm in the PEX glaucoma group. The difference among the PEX (−) group, the PEX syndrome and the PEX glaucoma groups was significant (p < 0.001, p = 0.030, respectively). There was a significant (+) correlation between intraocular pressure and CCT in the eyes with PEX (r = 0.307, p = 0.001). However, there was no statistically significant correlation between CCT, Schirmer and tear break up time tests in the eyes with PEX. Conclusions: PEX material can cause decrease in tear film secretion and disturb tear film stability. There is no effect of PEX-induced dry eye on CCT. Lower CCT values in the eyes with PEX material may be a result of decrease in corneal stromal cell density. Moreover, higher CCT values may be because of decreased endothelial cells in PEX glaucoma patients.

Plateletcrit in Ocular Pseudoexfoliation Syndrome.

Purpose: The aim of this study was to compare all platelet markers, especially plateletcrit (PCT, total platelet mass), in patients with and without ocular pseudoexfoliation (PEX) syndrome. Methods: One hundred six patients with ocular PEX syndrome (study group) and 106 individuals without ocular PEX syndrome (control group) were enrolled in this retrospective case-control study. The biochemical/hematological laboratory results of both the study and control groups were analyzed by a clinician blinded to the group assignments. The main outcome measures were the PCT, platelet count (PLT), mean platelet volume (MPV), and platelet distribution width (PDW). Results: The mean PCT in the study and control groups were 0.206%±0.520% and 0.171%±0.410%, respectively (P<0.001), and the mean PDW in the study and control groups were 16.12%±1.21% and 14.68%±1.40%, respectively (P<0.001). There were no differences in the MPV or mean PLT (P=0.138 and P=0.055, respectively). The PCT cutoff value was 0.180 (area under the receiver operating characteristics curve, 0.706; P<0.001; 65% sensitivity; 74% specificity). Conclusions: The PCT and PDW were significantly higher in patients with than without ocular PEX syndrome. These increased parameters may cause microvascular blood flow resistance and the heightened inflammatory response caused by excessive platelet activity, as with other cardiovascular diseases, and may also decrease aqueous humor outflow in ocular PEX syndrome.

Evaluation of the relationship between corneal biomechanic and HbA1C levels in type 2 diabetes patients.

Purpose To evaluate the corneal biomechanical properties due to the glycosylated hemoglobin (HbA1C) levels using the ocular response analyzer (ORA) in the patients with type 2 diabetes mellitus (DM). Methods ORA values were obtained from 156 eyes of subjects with type 2 DM and 74 eyes of healthy control subjects with similar age and sex. Subjects were divided into three groups: Group 1, healthy control subjects; Group 2, diabetes patients with HbA1C <7%; and Group 3, diabetes patients with HbA1C ≥7%. Corneal biomechanical parameters: corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc) measurements were obtained using ORA. Ultrasound pachymetry was used for measurement of central corneal thickness (CCT). Results CH and CRF were significantly different in each of the three groups (P-values for CH respectively; Groups 1 and 2=0.008, Groups 1 and 3, and Groups 2 and 3, <0.001, and for CRF respectively; =0.002, <0.001, <0.001). CCT was significantly different between Groups 1 and 3 and Groups 2 and 3 (P<0.001) but was insignificant between Groups 1 and 2 (P=0.965). IOPcc was not different between Groups 1 and 2 (P=0.524), and Groups 2 and 3 (P=0.115), but was significantly different between Groups 1 and 3 (P=0.003). IOPg was statistically different between each of the three groups (respectively; Groups 1 and 2, P=0.015, Groups 1 and 3, and Groups 2 and 3, P<0.001). Conclusion Both diabetes groups were affected in terms of corneal biomechanical properties when compared to healthy subjects, there was also a positive correlation between HbA1C level and intraocular pressure.

The Effect of Dexamethasone Intravitreal Implant on Retinal Nerve Fiber Layer in Patients Diagnosed with Branch Retinal Vein Occlusion

ABSTRACT Purpose: To evaluate the effect of a single dose of intravitreal dexamethasone (DEX) implant on retinal nerve fiber layer (RNFL) thickness in patients with branch retinal vein occlusion (BRVO) in a 6-month period. Materials and methods: This retrospective observational study included the patients with BRVO who received intravitreal DEX implant and whose assessment included the baseline RNFL thickness measurements. The data of 26 eyes of 24 patients were retrospectively analyzed. Spectral domain optic coherence tomography was used to measure peripapillary RNFL thickness in six regional subfields. Intraocular pressure (IOP) values at each visit were recorded. The data of single dose DEX implant during 6 months were assessed. Results: The mean preoperative and postoperative 6th month nasal RNFL values were 85.4 ± 23.0 μm and 82.1 ± 17.6 μm, respectively, and the difference between the measurements was not statistically significant (p = 0.372). There was a slight decrease in the mean RNFL values postoperatively compared to the baseline values in all quadrants except supero-temporal quadrant; however, none of them reached statistically significant level (p > 0.05). The mean IOP values before and 6 months after implantation were 15.7 ± 2.9 mmHg and 16.5 ± 4.2 mmHg, respectively. The difference between the 6th month IOP values and baseline IOP values was not statistically significant (p = 0.236). Conclusion: Intravitreal DEX implant seems to have no adverse effect on RNFL thickness in BRVO patients in a 6-month period.

In-vivo corneal biomechanical analysis of unilateral keratoconus

AIM To evaluate and compare corneal biomechanical findings measured by ocular response analyzer, topographic and pachymetric findings in patients with unilateral keratoconus patients and healthy controls. METHODS This is an observational, case-control study. Patients with keratoconus in one eye and forme fruste keratoconus in the fellow eye were compared with sex and age matched with controls healthy subjects. All subjects were evaluated with rotating scheimpflug imaging system. The receiver-operating-characteristic curves were analyzed to evaluate the sensitivity and specificity of the parameters. RESULTS Twenty-seven patients with keratoconus in one eye and forme fruste keratoconus in the fellow eye were compared with 40 eyes of 40 normal subjects. Corneal hysteresis (CH) was 8.0±1.7 mm Hg in keratoconus group, 8.3±1.6 mm Hg in forme fruste keratoconus group, and 9.8±1.6 mm Hg in control groups (P=0.54 between keratoconus and forme fruste keratoconus groups, P<0.01 between control group and other groups). Corneal resistance factor (CRF) was 7.1±2.2 mm Hg in keratoconus group, 7.8±1.2 mm Hg in forme fruste keratoconus group and 9.9±1.5 mm Hg in control group (P<0.001 between control group and other groups). Using receiver-operating-characteristic analysis, the area under curve values of the parameters to distinguish forme fruste keratoconus from control subjects were: CH (0.768), CRF (0.866). Best cut-off points were 9.3 mm Hg and 8.8 mm Hg for CH and CRF respectively. CONCLUSION Ocular response analyzer parameters (CH and CRF) are found to be significantly lower in forme fruste keratoconus patients compared to normal control subjects.