Analysis of choroidal thickness in dry type of age-related macular degeneration using spectral-domain optical coherence tomography

To evaluate and compare the choroidal thickness in old-aged (>45 years) patients with dry type of age releated macular degeneration and age-matched normal population using spectral-domain optical coherence tomography. A cross-sectional study was conducted in a tertiary eye clinic center. The study consists of 2 study and 1 control groups. Fifty-three eyes of 27 patients and 56 eyes of 28 patiens who were firstly diagnosed with dry type of age releated macular degeneration were participated in the study groups and 64 eyes of 32 individuals without any retinal or choroidal disorder were participated in the control group. All 173 eyes underwent a detailed ophthalmologic examination including optical coherence tomography. An experienced observer measured choroidal thickness using spectral-domain optical coherence tomography. No statistically significiant difference was established between the means of age among three groups. The distribution of choroidal thickness measurements demonstrated a normal distribution in all 3 groups. No statistically significant differences were found between the study groups in terms of mean choroidal thickness, but there were significant differences in mean choroidal thickness between the control group and both study groups. In our study, it was observed that choroidal thickness can be analysed by spectral-domain optical coherence tomography and choroidal thickness in patients with dry type of age releated macular degeneration is appeared to be thinner than normal age-matched population. [Med-Science 2018; 7(3.000): 552-6

Prevalence of Keratoconus and Subclinical Keratoconus in Subjects with Astigmatism Using Pentacam Derived Parameters

Purpose: To determine the prevalence of keratoconus (KCN) and subclinical KCN among subjects with two or more diopters (D) of astigmatism, and to compare Pentacam parameters among these subjects. Methods: One hundred and twenty eight eyes of 64 subjects with astigmatism ≥2D were included in the study. All subjects underwent a complete ophthalmic examination which included refraction, visual acuity measurement, slit lamp biomicroscopy, retinoscopy, fundus examination, conventional corneal topography and elevation-based topography with Pentacam. The diagnosis of KCN and subclinical KCN was made by observing clinical findings and topographic features; and confirmed by corneal thickness and elevation maps of Pentacam. Several parameters acquired from Pentacam were analyzed employing the Mann-Whitney U Test. Results: Mean age of the study population was 29.9±9.8 (range 15-45) years which included 39 (60.9%) female and 25 (39.1%) male subjects. Maximum corneal power, index of vertical asymmetry, keratoconus index and elevation values were significantly higher and pachymetry was significantly thinner in eyes with clinical or subclinical KCN than normal astigmatic eyes (P< 0.05). Conclusion: The current study showed that subjects with 2D or more of astigmatism who present to outpatient clinics should undergo corneal topography screening for early diagnosis of KCN even if visual acuity is not affected. Pentacam may provide more accurate information about anterior and posterior corneal anatomy especially in suspect eyes

Traumatic cataract study: Surgical outcomes of blunt versus penetrating ocular injuries

The aim of the present study is to evaluate the results of traumatic cataract surgery with regard to the type of trauma, mainly in the assessment of visual acuity. Forty-four patients who had been diagnosed with traumatic cataracts were included in this retrospectively designed study. The patients were divided into blunt and penetrating groups according to the type of trauma. Pre- and postoperative ocular findings of the cases were evaluated. Visual acuity, intraocular pressure, intra- and postoperative complications, associated injuries, and surgical approaches were analyzed. Thirty-three of the cases were male (75%) and 11 (25%) were female. There were 23 patients (52.27%) in the blunt group and 21 (47.72%) in the penetrating group. The pre-operative mean vision of the subjects included in the blunt and penetrating groups was 0.82 and 0.96 logMAR, respectively. Ten (22.72%) eyes were hypotonic ( [Med-Science 2019; 8(1.000): 37-41

The Distribution of the Photoreceptor Outer Segment Length in a Healthy Population

Purpose. To evaluate the effects of age and sex on the photoreceptor outer segment (PROS) length in healthy eyes, using spectral-domain optical coherence tomography (SD-OCT). Methods. A total of 97 eyes of 97 healthy participants (spherical equivalent < ±1 diopters [D]) were scanned with SD-OCT. The patients were divided into 3 groups by age: group 1 (0–20 years), group 2 (21–40 years), and group 3 (41–60 years). The PROS length was defined as the distance from the inner surface of IS/OS (inner segment/outer segment) band to the inner surface of retinal pigment epithelium (RPE). Results. The mean PROS length was 52.01 ± 3.79 μm in females and 53.41 ± 3.37 μm in males (p=0.061). The mean PROS length of the different groups was 53.70 ± 3.18 μm (0–20 years), 52.14 ± 3.64 μm (21–40 years), and 52.20 ± 3.95 μm (41–60 years) (p=0.155; ANOVA test). Multiple linear regression analysis revealed a −0.039 μm decline in PROS length per year (p=0.074) and a −1.408 μm decline in females (p=0.055). Conclusion. The difference in PROS length was not statistically significant neither for age nor for gender; females tended to have a lower PROS length than males, and PROS length was slightly higher in the first two decades of life

Tunable near-field radiative transfer by III-V group compound semiconductors

Near-field radiative transfer (NFRT) refers to the energy transfer mechanism which takes place between media separated by distances comparable to or much smaller than the dominant wavelength of emission. NFRT is due to the contribution of evanescent waves and coherent nature of the energy transfer within nano-gaps, and can exceed Planck's blackbody limit. As researchers further investigate this phenomenon and start fabrication of custom-made platforms, advances in utilization of NFRT in energy harvesting applications move forward day by day. In designing and manufacturing such harvesting devices, chemical and physical properties of surfaces and wafers are important for development of effective solutions. In this work, we compare several III-V group compound semiconductor wafers (mainly GaAs, InSb, and InP) from fabrication point of view, in order to explore their possible use in future devices. The results presented here show that the type of dopant, wafer temperature, and gap size are very important factors as they affect the NFRT rates. GaAs, InSb, and InP wafers significantly enhance the near-field fluxes beyond the blackbody rates, and n-type InSb yields to the highest enhancement. For GaAs, p-type yielded a higher radiative flux compared to n-type GaAs, as oppose to n-type InSb outperforming its p-type and undoped counterparts. Furthermore, the possible use of n-InSb as the TPV cell at 550K is discussed for effective energy harvesting. These findings can be useful for determination of the proper material type for emitting and non-emitting NFRT-based energy harvesting devices

Tolerating subretinal fluid in the treatment of neovascular age-related macular degeneration with intravitreal aflibercept

Objective: To compare the anatomical and functional outcomes of intensive and relaxed intravitreal aflibercept regimen in the management of neovascular age-related macular degeneration. Methods: The medical records of 50 eyes of 50 patients with treatment-naive neovascular age-related macular degeneration, who underwent intravitreal aflibercept therapy in the Retinal Department of University of Health Sciences Okmeydanı Training and Research Hospital (Istanbul, Turkey), were retrospectively reviewed. The demographic features and best-corrected visual acuities at baseline and at 1st-, 2nd-, 3rd-, 4th-, 6th-, 10th- and 12th- months, optical coherence tomography measurements, presence of intraretinal fluid, subretinal fluid and intraocular pressure values were studied. The patients were divided into two groups: intensive (subretinal fluid intolerant) and relaxed (<200 microns subretinal fluid tolerated) intravitreal aflibercept regimens. Results: The change in the mean best-corrected visual acuities from baseline to 12th month was 13.72 ± 33.97 letters in the intensive treatment group and 8.68 ± 27.22 in the relaxed group. There was no statistically significant difference between the groups ( p  = 0.566). Similar proportions of both groups achieved ⩾10 letters gain (%48 vs. %40, respectively; p  = 0.755) and ⩾10 letters loss (%20 vs. %24, respectively; p  = 0.755). The mean central subfield thickness values decreased statistically significantly in both groups ( p  < 0.001). There was no statistically significant difference between the groups (442.40 ± 161.32 to 318.0 ± 63.10 vs. 431.64 ± 151.52 to 303.08 ± 140.91, respectively; p  = 0.724). The mean total injection numbers were significantly lower in the relaxed group (6.4 ± 1.65 vs. 4.8 ± 1.45, respectively; p  = 0.01). Conclusion: Relaxed intravitreal aflibercept regimen has comparable efficiency and safety outcomes at 12 months with intensive intravitreal aflibercept regimen with fewer injections in the management of neovascular age-related macular degeneration

Visual recovery comes after anatomical recovery after intravitreal aflibercept treatment in macular edema secondary to branch retinal vein occlusion

To determine the time of anatomical and visual responses of intravitreal aflibercept (IVA) injections in patients with naive macular edema (ME) due to branch retinal vein occlusion (BRVO). 54 eyes of 54 patients who had three IVA injections after BRVO were retrospectively studied. All of the patients had three monthly IVA injections. SD-OCT was performed at the initial visit and one month after every injection. Changes in central macular thickness (CMT), best corrected visual acuity (BCVA) were determined. Results: 28 of 54 patients were women and 26 of 54 patients were man. Mean age was 62.56±2.35 years. Mean BCVA of the patients was logMAR 1.00±0.13 and the mean CMT was 476±35 µm. After first injections; mean BCVA and CMT were improved to logMAR 0.73±0.19, 279±15 µm respectively. These improvements were statically significant (p=0.047 and p=0.000 respectively). After second injections there was not any improvement in BCVA or CMT. The mean BCVA logMAR 0.75±0.18 and mean CMT 279±10 µm (p=0.725 and p=0.991). After third injections mean CMT was 267±6 µm and mean BCVA was logMAR 0.58±0.15. Although after third injections, CMT did not change but BCVA was statically significant improved (p=0.77 and p=0.036 respectively). Visual recovery comes after anatomical recovery after intravitreal aflibercept injections in patients with naive ME due to BRVO. [Med-Science 2018; 7(4.000): 810-2

Efficacy and safety of intravitreal aflibercept therapy in diabetic macular edema

To conduct a retrospective evaluation of the efficacy and safety of intravitreal aflibercept treatment in diabetic macular edema. Patients treated with intravitreal aflibercept for diabetic macular edema participated in this study. Three injections were administered to the previously untreated 76 eyes of 50 patients for 3 consecutive months with one-month interval. The results were evaluated retrospectively by analyzing the patients medical records. The patients values of best corrected visual acuity inverted according to Snellen chart, and their central macular thickness and intraocular pressure were compared before and after treatment. The average age of the patients was 57.2 ± 10.1. Of the cases, 77.6% were phakic, and 22.4% were pseudophakic. The increases in best corrected visual acuity in the first month after each injection and at the end of the third month were statistically significant (p &lt; 0.001). The mean central macular thickness was 405.63 ± 106.93 &#956;m before treatment and 288.83 ± 62.49 &#956;m after the third injection. This reduction in the mean central macular thickness was statistically significant (p &lt; 0.05). During and after the three-month follow-up of the injection application process, the most common observed ocular side effect was subconjunctival hemorrhage (34.2%). During or after the applications, no systemic side effects, such as sudden death, thromboembolic events, or myocardial infarction, were seen. Functionally and anatomically, intravitreal aflibercept injection therapy in diabetic macular edema is an effective treatment option because it improves visual acuity and decreases central macular thickness. [Med-Science 2019; 8(2.000): 412-7

Restoration of photoreceptor layer and its prognostic value in eyes with macular edema due to branch retinal vein occlusion

To evaluate the restoration of outer segment ellipsoid zone (EZ) layer and its prognostic value in visual gain following resolution of macular edema (ME) due to branch retinal vein occlusion (BRVO). In this retrospective study,33 eyes of 33 patients with ME due to BRVO who underwent intravitreal ranibizumab (IVR) injections were studied. All of the patients had the resolution of macular edema after IVR therapy. At baseline and final visit, SD-OCT scans were obtained. Best-corrected visual acuity (BCVA), central macular thickness (CMT) and integrity of outer segment ellipsoid zone (EZ) defects were determined. We divided the eyes with initial EZ defects into two groups. Group-1 had restoration of EZ and group-2 had EZ defects before and after treatment. 14 of 33 eyes (42.4%) did not have EZ defects and 19 of 33 eyes had EZ defects before treatment. 9 eyes (27.3%) had restoration of EZ defects and 2 patients (6.1%) had EZ defects after treatment while they did not have at initial visit. According to EZ change status (group-1 and group-2) the groups were similar in terms of initial BCVA and CMT. Group-1 had better final BCVA (p=0.005). There was a statically significant difference in BCVA improvement between groups (p=0.001). Disorganization of photoreceptors can have recovery after resolution of ME with ranibizumab treatment and to have better BCVA after resolution of ME, restoration of the structure of the photoreceptors is required. [Med-Science 2018; 7(3.000): 491-3