Pelin Yilmazbas

Quantitative assessment of corneal clarity in keratoconus: a case control study of corneal densitometry.

Purpose To evaluate corneal clarity quantitatively by corneal densitometry measurement in treatment-naive keratoconus patients and to compare these results with those of healthy control subjects. Methods Corneal densitometry measurement of consecutive treatment-naive keratoconus patients and healthy control subjects was performed by Scheimpflug corneal topography (Pentacam®HR). Corneal densitometry measurements were expressed in gray scale unit (GSU) and the data from the right eyes of subjects were used for statistical analysis. Results A total of 102 subjects (51 patients with keratoconus [27 male, 24 female] and 51 healthy control subjects [24 male, 27 female]) were included in the study. There was no statistically significant difference with regard to the mean age (p = 0.910) or distribution of sex (p = 0.552) between the groups. There were significant differences in corneal densitometry values of the groups in central 2 mm (17.95 ± 0.33 GSU in keratoconus and 16.43 ± 0.24 GSU in controls, p<0.001) and in annulus of 2 to 6 mm in diameter (15.88 ± 0.26 GSU in keratoconus and 15.02 ± 0.22 GSU in controls, p = 0.015). When considering the measurements in different depths, the anterior layer displayed the highest densitometry value compared to that of both the central and posterior layers. Corneal densitometry of anterior 0-2 mm was positively correlated with simulated K value (r = 0.446, p = 0.001), whereas it was negatively correlated with central corneal thickness (r = −0.361, p = 0.016) in keratoconus patients. Conclusions Treatment-naive keratoconus patients have significantly higher corneal densitometry values in central cornea when compared to healthy control subjects. The clinical relevance should be further studied in detail.

Histopathological Analysis of Internal Limiting Membrane Surgically Peeled From Eyes with Epiretinal Membrane

ABSTRACT Purpose: To investigate histopathological changes of internal limiting membrane (ILM) in patients with epiretinal membrane (ERM) Materials and Methods: Forty-two eyes of 42 patients who were diagnosed as ERM and enrolled for vitreoretinal surgery were included in this study. Brilliant Blue G (BBG) was used to stain the ILM in all patients. ILM was peeled in all subjects and analyzed by light microscopy (methylene blue-Azur II × 40). ILM samples were then fixed in 2.5% glutaraldehyde solution and examined in JEOL-JEM 1400 and 2100F electron microscope and photographed by CCD camera (Gatan Inc., Pleasanton, CA). Results: Remained ERM fragments were observed on 80% of ILM’s. Vacuolization of ILM was observed in a patient with diabetic ERM. There were cells and cellular fragments observed mostly at retinal side of ILM which was likely to be a fragment of Muller cells of retina. Conclusions: Most of the ILM’s had residual ERM tissue and contained cells and cellular fragments at retinal side of ILM’s. ILM peeling might have a role in decreasing ERM recurrence by removal of residual ERM tissues.

Intralenticular Sustained-Release Dexamethasone Implant: Is It Still Effective on Macular Edema?

Purpose: To report the therapeutic efficacy of an accidentally injected intralenticular sustained-release dexamethasone implant in a patient with macular edema secondary to branch retinal vein occlusion and shortly discuss the management strategy of this rare complication. Methods: Complete ophthalmological examination and optical coherence tomography imaging were performed at each visit. Results: The implant accidentally caused a posterior capsular tear during the procedure and was injected into the crystalline lens because of an involuntary head movement of the patient. Since the anterior segment was normal, and the resultant cataract and implant itself did not obscure the visual axis, the decision was made to observe the patient with intralenticular implant, preserve the therapeutic effect and avoid reinjection. The macular edema resolved within time, while visual acuity did not show significant improvement due to an increase in lens opacification. The patient underwent phacoemulsification surgery at 7 months after the injection with implantation of posterior chamber IOL into the capsular bag. Conclusion: Inadvertent injection of sustained-release intravitreal dexamethasone implant into the crystalline lens is an uncommon but possible complication that is mostly caused by surgeon inexperience, improper technique and uncontrolled head movement during the procedure. Once this complication occurs, early phacoemulsification and repositioning of the implant into the vitreous is the frequently preferred management strategy. However, remarkable decrease in macular edema and visual acuity improvement can also be achieved without an immediate surgical intervention.

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.

Evaluation of the shifting of the line of sight and higher order aberrations of eyes with keratoconus after corneal cross-linking

AIM To evaluate changes in the coordinates of the line of sight (LoS) and higher order aberrations (HOAs) of eyes with keratoconus, following corneal cross-linking (CXL). METHODS All patients (93 eyes) underwent detailed ophthalmologic examination and Pentacam HR measurements at baseline and at 3, 6, and 12 months after corneal CXL. LoS coordinates on the horizontal (x) and vertical (y) axes, vertical coma, vertical trefoil, spherical aberration, total root-mean square (RMS), and HOA-RMS values were recorded along with visual acuity and topographical parameters. RESULTS LoS significantly shifted to the nasal region after corneal CXL in both right and left eyes (p=0.003 and p=0.01, respectively). Horizontal axis values of both eyes significantly shifted to the temporal region at postoperative 6th months compared to the baseline measurements (p=0.02 and p=0.02, respectively) and remained the same between postoperative 6th months and 12th months (p=1.00 and p=0.97, respectively). Total-RMS, HOA-RMS, vertical coma, and spherical aberration values significantly improved after corneal CXL (p<0.001, p=0.02, p=0.04, and p<0.001, respectively). The improvements in HOAs were significant at postoperative 6th months compared to the baseline measurements (p=0.003, p=0.02, p<0.001, and p=0.003, respectively) while remained the same between postoperative 6th months and 12th months (p>0.05 for all values). The changes in horizontal-axis coordinates in left eyes were significantly correlated with anterior elevation, anterior astigmatism, total-RMS and HOA-RMS changes (r2=0.20, p=0.03; r2=0.35, p<0.01; r2=0.50, p<0.001 and r2=0.35, p=0.004; respectively). CONCLUSIONS LoS significantly shifted to the nasal region and HOAs improved after corneal CXL and these changes stabilized 6th months after corneal CXL. It would be more better to perform refractive surgery in crosslinked corneas at least 6th months after corneal CXL.

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.

Evaluation of corneal biomechanical properties using an ocular response analyser to examine aphakic and pseudophakic patients after congenital cataract surgery.

We evaluated corneal biomechanical properties in aphakic and pseudophakic patients after congenital cataract surgery and compared the data with those of age‐matched normal subjects.

Assessment of Corneal Densitometry in Rheumatoid Arthritis Patients

Objectives: To evaluate corneal densitometry and anterior segment parameters of rheumatoid arthritis (RA) patients and compare these results with those of age-matched healthy control subjects. Materials and Methods: Anterior segment parameters and corneal densitometry of patients with RA and healthy control subjects were assessed by Scheimpflug corneal topography. For densitometry analysis, the 12-mm diameter area of the cornea was subdivided into four concentric radial zones and anterior, central, and posterior layers based on corneal depth. Right eyes of subjects were used for statistical analysis. Results: Twenty-three consecutive patients with RA and 22 healthy control subjects were included in the study. There was no significant difference with regard to age (p=0.487) or gender (p=0.514). When anterior segment parameters of both groups were compared, no significant difference was found (p>0.05). Total corneal densitometry values were statistically higher in the RA group (p=0.030). In addition, when subdivisions of the cornea were evaluated, higher densitometry values were found in the RA group in 0-2 and 2-6 mm radial zones both in the anterior and total depth (p=0.001, p=0.003 for the 0-2 mm zone and p=0.002, p=0.009 for the 2-6 mm zone). Corneal densitometry measurement was not correlated with central corneal thickness or simulated keratometry value in RA patients or healthy control subjects. Conclusion: The corneal densitometry values were higher in RA patients when compared to healthy control subjects, even if they had clinically clear corneas. Corneal densitometry as an objective measure of corneal clarity warrants further studies in order to ascertain its clinical relevance in RA patients.

Effect of preoperative factors on visual acuity, corneal flattening, and corneal haze after accelerated corneal crosslinking

Purpose To evaluate the preoperative characteristics that might influence corneal flattening, visual acuity, and corneal haze after accelerated (9 mW/cm2) corneal collagen crosslinking (CXL). Setting Ulucanlar Eye Hospital, Ankara, Turkey. Design Retrospective case series. Methods Accelerated corneal CXL was performed in eyes with progressive keratoconus. Preoperative characteristics included age, sex, uncorrected distance visual acuity and corrected distance visual acuity (CDVA), maximum keratometry (K), corneal thickness, corneal hysteresis, the corneal resistance factor, cone location, and densitometry values. Regression analysis was performed to determine the predictive factors for accelerated corneal CXL outcomes. Results The study included 162 eyes of 146 patients with a mean age of 19.3 years ± 4.4 (SD). There was 0.20 logMAR improvement in CDVA (P = .011), 1.85 diopter flattening in maximum K (P < .001), and 5.84 grayscale unit increase in densitometry (P < .001) at 1 year. Multivariate analysis found that preoperative CDVA was a predictive factor for CDVA improvement (ß coefficient, 0.233; 95% confidence interval [CI], −0.054 to 0.477; P = .003). Preoperative maximum K was a predictive factor for corneal flattening (ß coefficient, 0.506; 95% CI, 0.185 to 0.681; P < .001). Univariate analysis found that preoperative densitometry was a predictive factor for increasing corneal densitometry (ß coefficient, 0.466; 95% CI, −0.122 to 0.683; P = .001) and corneal scar formation (ß coefficient, 0.256; 95% CI, 0.012 to 0.421; P = .041). Conclusions Patients with a worse preoperative CDVA and higher maximum K were most likely to have improvement after accelerated CXL. Patients with high preoperative densitometry were most likely to have scar formation after the procedure. Financial Disclosure None of the authors has a financial or proprietary interest in any material or method mentioned.

Effect of dorzolamide-timolol fixed combination prophylaxis on intraocular pressure spikes after intravitreal bevacizumab injection.

AIM To evaluate the effect of topical dorzolamide-timolol fixed combination prophylaxis on short term intraocular pressure (IOP) changes in patients who had intravitreal bevacizumab injection. METHODS One hundred and fifty one eyes of 151 patients which were followed up in retina clinic in Ulucanlar Eye Training and Research Hospital were evaluated in this study. Patients were divided into two groups. Group 1 consists of 75 patients who had topical dorzolamid-timolol medication two hours before injection; while Group 2 consists of 76 patients without prophylaxis. Demographic data, IOP measurements prior to the injection and one, thirty and sixty minutes and twenty-four hours after the injection were recorded. The data were analyzed using SPSS software version 15.0 (SPSS Inc., Chicago, IL, USA). RESULTS There were no significant difference between two groups in age, gender distrubition and indications for injections. The mean IOPs in Groups 1 and 2 prior to the injection (T0) were 17.84±0.43 and 18.15±0.43 mm Hg, one minute after the injection (T1) were 29.75±1.6 and 34.44±1.59 mm Hg, 30min after the injection (T30) were 20.06±0.6 and 21.71±0.59 mm Hg respectively. The mean IOPs were 18.26±0.56 mm Hg in Group 1 and 19.78±0.56 mm Hg in Group 2 sixty minutes after the injection (T60). All IOP values after the injection were compared between two groups, there was a significant difference between two groups only on T1; one minute after the injection (P=0.04). There were a statiscially significant difference between the baseline values and other recorded values; except on T60, in Groups 1 and 2 (P<0.05). CONCLUSION After intravitreal bevacizumab injection; we observe a transient IOP elevation which normalizes about one hour after intravitreal injection. In patients who had topical dorzolamid-timolol combination prophylaxis before injections, a significant decrease is seen in IOP spikes due to this injection. The appropiate approach will monitor IOP after intravitreal injection and evaluate the using prophylactic antiglaucomatous drugs before the injection in patients with ganglion nerve cell damage.