Fovea Area Research Articles

Chorio-retinal vessel density in women affected by functional hypothalamic amenorrhea: a monocentric observational cross-sectional study to evaluate the impact of hypoestrogenism on chorio-retinal vascularization

PurposeFunctional hypothalamic amenorrhea (FHA) is characterized by an estrogen deficiency which in turn can cause vascular dysfunction. The aim of this study is to evaluate any changes in the chorio-retinal circulation in patients affected by FHA. 24 patients with FHA and 24 age-matched controls underwent a gynecological evaluation and an OCT angiography (OCTA) to study chorio-retinal vascularization.ResultsOCTA in FHA patients showed an increase in vessel density in the choriocapillaris (CC) layer (both in the fovea area, at 5% p value = 0.037 and in the whole area, at 5% p value = 0.028) and an increase in vascular density in the deep fovea (DVP) (at 10% p value = 0.096) in the whole district compared to controls. Simple linear regressions show a significant negative association between CC vessel density and insulin (p = 0.0002) and glucose values (p = 0.0335) for the fovea district and a negative association between DVP vessel density and endometrial thickness (at 10%, p value: 0.095) in the whole district.ConclusionOur study shows that CC vessel density is increased in women affected by FHA. This could represent a compensation effort to supply the vascular dysfunction caused by estrogen deficiency. We also found an increasing trend in vascular density in DVP associated with the decrease of endometrial thickness, an indirect sign of estrogenization. Considering that these changes occur in absence of visual defects, they could be used as a biomarker to estimate hypoestrogenism-induced microcirculation changes before clinical appearance.

Chorioretinal biomarkers in hypothalamic amenorrhea

PurposeThe aim of our study was to evaluate changes in the retinal and choriocapillaris circulations in patients with hypothalamic amenorrhea.MethodsProspective, cross-sectional observational study on 25 patients (50 eyes) diagnosed with hypothalamic amenorrhea and 25 age-matched healthy women. Optical coherence tomography angiography (OCTA) was used to evaluate the vessel density (VD) of superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris VD layers in whole 6.4 × 6.4-mm image and in fovea grid-based image. In patients’ group, systemic parameters were collected: body mass index (BMI), endometrial rhyme thickness, follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin, insulin, and cortisol.ResultsSCP and DCP did not show any statistical difference when comparing patients and controls (all p > 0.05). Differently, choriocapillaris VD in the whole region showed a non-significant tendency toward higher values in the patients group in both eyes (p = 0.038 for right eye [RE], p = 0.044 for left eye [LE]). Foveal choriocapillaris VD was higher in hypothalamic amenorrhea women vs. healthy controls (66.0 ± 2.4 vs. 63.7 ± 6.6%, p = 0.136 for RE; 65.0 ± 2.4 vs. 61.6 ± 7.0%, p = 0.005 for LE). Focusing on correlation with systemic parameters, SCP and DCP foveal density had a medium/high effect size with endometrial rhyme, along with DCP in the fovea area vs. cortisol and SCP in the whole area vs. FSH.ConclusionWhen comparing hypothalamic amenorrhea patients to healthy subjects, OCTA detected changes in the choriocapillaris layer, showing increased VD in the early stage of the systemic pathology, suggesting that microvascular “compaction” could be a first phase of hypoestrogenism adaptation.

Microvascular Changes after Epiretinal Membrane Vitrectomy with Intraoperative Intravitreal Dexamethasone Implant: An OCT Angiography Analysis.

We aimed to explore microvascular changes evaluated with optical coherence tomography angiography (OCTA) in patients undergoing epiretinal membrane (ERM) pars-plana vitrectomy (PPV) combined with intravitreal Ozurdex implantation, compared with standard PPV. (2) Methods: Prospective interventional analysis on 25 eyes undergoing PPV + Ozurdex (Group A) and 25 eyes undergoing PPV alone. Best corrected visual acuity (BCVA) and OCTA parameters, such as vessel density (VD) of the superficial and deep capillary plexi (SCP and DCP) in the whole 6.4 mm × 6.4 mm and fovea area, were evaluated preoperatively and 3 months after surgery. (3) Results: Postoperative BCVA significantly improved in both groups. No cases of post-operative cystoid macular edema (CME) were reported in Group A vs. two eyes in Group B. In Group A we found a statistically significant increase of SCP's VD in either the whole image (from 42.1 ± 4.1 to 45.6 ± 4.3%, p = 0.01) and the fovea image (from 38.5 ± 7.5 to 41.7 ± 4.2%, p = 0.03). In Group B, we reported no significant variations in the SCP's VDs. In the DCP, VD significantly increased only in the whole image in Group A. Stage 4 ERMs showed the greatest improvement in VD, especially in Group A. (4) Conclusions: Intraoperative Ozurdex prompted a significant BCVA recovery and limited the occurrence of postoperative CME compared to the standard procedure. Moreover, Ozurdex implant is associated with a better restoration of microvascular structure in SCP and DCP.

A non-iterative foveated single-pixel imaging using fast transformation algorithm

Inspired by the human eye retina, foveated single-pixel imaging employs an iterative algorithm, which, unfortunately, poses a challenge for real-time imaging due to its time-consuming nature. To address this issue, we present a non-iterative foveated single-pixel imaging method based on a computationally fast algorithm, reducing time consumption by five orders of magnitude. The fast algorithmic transform facilitates the acquisition of foveated reconstructions. In addition to mimicking human saccadic eye movements, the foveated strategy adapts to motion tracking through the foveal gaze control method. During high-resolution imaging in the fovea area, the maximum sensing area expands 3.14 times, similar to human vision. The proposed retina-like single-pixel imaging has great potential in future applications with the advantages of avoiding complex optics design, low time consumption, and wider vision field.

The Incidence and the Clinical Course of Retinal Complications of Intracameral Cefuroxime in Cataract Surgery

Aim. To determine the incidence and the clinical course of retinal complications of intracameral administration of cefuroxime in minimally invasive cataract surgery.Methods. From 2016 to 2021, a prospective clinical study was conducted at the Volga District Medical Center of the Federal Medical and Biological Agency of Russia, which included patients with cataract in one or two eyes to be surgically treated. All patients received 1 mg of cefuroxime injected into the anterior chamber at the end of surgery. All patients underwent ophthalmological examination including evaluation of best corrected visual acuity with determination of logarithm of minimum angle of resolution (logMAR), tonometry, biomicroscopy, and ophthalmoscopy. Each patient before and the day after surgery underwent optical coherence tomography of the retina on a spectral optical tomograph RTVue-100 (Optovue). The dynamics of the condition was evaluated on days 3 and 7 after surgery.Results. Five cases of retinal complications of intracameral cefuroxime injection were identified during the 5-year study period. According to data of optical coherence tomography, retinal edema was localized in the internal nuclear layer of the retina, and the height of serous retinal detachment in the fovea area on the next day after surgery was 315.0 ± 11.0 µm and reduced statistically significantly to 59.8 ± 42.3 µm on the 3rd day after the intervention (p = 0.043). One week later, all patients had complete retinal adherence and recovery of visual function. Retinal edema did not recur in the long term after surgery.Conclusion. Serous retinal detachment with macular edema is the most common clinically relevant complication of intracameral antibiotic prophylaxis, which develops both in compliance with the dilution protocol and in overdose, and has a favourable prognosis.

A technology of vitreomacular traction treatment by single-port intravitreal injection of bacterial collagenase into the foveolar area

Purpose: to develop a technology for the treatment of vitreomacular traction (VMT) with intravitreal injection of bacterial collagenase so that the dosage corresponds to the instruction for use of the drug. Material and methods. We carried out the modeling of a variety of variants of collagenase delivery to the area where it should act, taking into account the standard average anatomical parameters of the normal eye. We used modern facilities available in present-day ophthalmic surgery appliances. Results. A technology of bacterial collagenase delivery to the foveolar region of the retina was developed which ensured the injection of 1 KE dosage as permitted by the instruction for use. 27G caliber instruments, a cannula with a silicone tip and an OMS-800 microscope (Topcon, Japan), equipped with the OFFISS imaging systems, were used to deliver the drug directly to the VMT area of 35 eyes. Of these, VMT could be eliminated in 26 cases (74.3%), the best corrected visual acuity increased by 0.20 ± 0.21 (from 0.46 ± 0.21 to 0.66 ± 0.26). Conclusion. The developed technology of VMT treatment may be used in clinical practice as it ensures an effective concentration of the bacterial collagenase in the fovea area using the minimum dose recommended by the manufacturer in the instruction for drug use while avoiding retinal traumatization during the procedure.

Treating diabetic macular edema: comparative efficacy of 577 nm laser navigation exposure and threshold 532 nm laser coagulation combined with anti-angiogenic therapy

The Navilas 577 laser system integrates a laser coagulator with a tracking system and a fundus camera. The system ensures operation planning and representing the results of optical coherence tomography on the fundus image, which makes the treatment fast, clearly observable and safe and minimizes damage to healthy tissues.Purpose. To compare the results of threshold laser coagulation in the treatment of DME using a Navilas 577 laser and a Quantel Medical 532 nm device.Materials and methods. 64 patients aged 41–80 (64 eyes) with DME less than 350 μm high were examined after intravitreal administration of angiogenesis inhibitors and threshold lattice laser coagulation using Quantel Medical 532 and Navilas 577.Results. A lower height of the edema and an increase in visual acuity were observed in both cases, but in the Navilas 577 laser group the BCVA was higher than in Quantel Madical 532, whilst the edema height in the Navilas 577 laser group in the central fovea area was less high.Conclusion. 1. The combination of retinal laser coagulation and angiogenesis inhibitors in the treatment of low DME (less than 350 μm) provides good results, so it can be justified and expedient in real clinical practice. The efficiency of 577 nm navigation laser exposure was found to be higher than that of threshold 532 nm laser coagulation.

Choriocapillary regional characteristics in idiopathic macular holes using optical coherence tomography angiography

Purpose: To evaluate the characteristics of vascular density (VD) of the retinal capillary plexuses in idiopathic macular hole (IMH), the fellow eye, and healthy control eyes by optical coherence tomography angiography (OCTA). Methods: A retrospective cases series study involving 20 unilateral eyes (20 patients) with IMH, the unaffected fellow eyes (n = 20) and 20 health controls, with age- and sex-matched, was conducted in Shanxi Eye Hospital from January 2019 to December 2021. VD of the retinal capillary plexuses measurements were obtained by OCTA. Results: Four quadrants of superficial capillary plexuses (SCP) in IMH eyes were not significant compared with that in the unaffected fellow eyes (all P > 0.05). The four quadrants of deep capillary plexuses (DCP) in IMH eyes were lower than that in the unaffected fellow eyes (all P < 0.05). Different regions retinal thickness in the IMH eyes was higher than that in the unaffected fellow eyes (all P < 0.05). a significant negative correlation between deep vessel density and retinal thickness in different quadrants among IMH eyes (all P < 0.05). Additionally, the correlation between the vascular density of SCP and retinal thickness was significant in macular fovea area (= 0.519, P = 0.019). <0.001. Conclusions: The morphology of retina and choroid in idiopathic macular hole is different from that in fellow eye. The thickness of choroid in the fovea area of the unaffected eye also showed a decreasing trend. Taken together, the mechanism of macular hole may be further understood, that is, the decrease of choroid thickness may occur before the macular hole formation. It was verified again that the choroidal blood flow area in macular fovea of IMH patients was significantly lower than that in fellow eyes and healthy eyes.

Photodynamic Therapy with Chlorin e6 Derivative for Chronic Central Serous Chorioretinopathy (Pilot Study).

Purpose: To evaluate the use of photodynamic therapy (PDT) with chlorin e6 (Ce6) derivative in patients with chronic central serous chorioretinopathy (CSC). Methods: Participants in this interventional, single-center clinical pilot study included 39 patients (39 eyes) with chronic CSC. Primary objectives were to assess safety and change in decimal best-corrected visual acuity (BCVA) during the 12-month follow-up. Secondary objectives were to evaluate change in central retinal thickness (CRT) in fovea area, maximal height of subretinal fluid (SRF), subfoveal choroidal thickness (SFCT) on spectral-domain optical coherence tomography, and number of treatments. Results: There were no systemic adverse events and ocular side effects. Mean decimal BCVA showed a significant increase from 0.49 ± 0.25 to 0.63 ± 0.28 (P = 0.001), mean CRT and maximal height of SRF decreased significantly from 335 ± 95 to 219 ± 69 μm and from 149 ± 84 to 32 ± 86 μm respectively (P = 0.001), comparing baseline and month 12. There was no significant difference between mean SFCT before PDT and at month 12. During all follow-up periods mean number of PDT treatments was 1.3 ± 0.7. Complete SRF resolution was observed in 82% (32 eyes) during observation period. Conclusion: Results of this pilot study demonstrate that PDT with Ce6 derivative is a safe method to treat eyes with chronic CSC. PDT with Ce6 derivative is the treatment option for chronic CSC. Further randomized controlled studies with a larger sample size and longer periods of follow-up are needed to assess the effectivity and safety of PDT with Ce6 derivative in chronic CSC.

Hyperreflective material serves as a potential biomarker of dyslipidemia in diabetic macular edema

PurposeThe aim of this study was to investigate the vision-affected optical coherence tomography (angiography) (OCT/OCTA)-based morphological characteristics of diabetic macular edema (DME) and to explain their possible underlying mechanisms from a systemic perspective. MethodsDiabetic patients with DME were included in this retrospective study. The clinical profiles and OCT/OCTA morphological characteristics were recorded. Linear mixed-model analyses were performed between best-corrected visual acuity (BCVA) and each OCT/OCTA morphological characteristic. Linear and logistic mixed-model analyses were performed between each vision-affected morphological characteristic and the clinical characteristics. ResultsEighty-five eyes of 85 patients were included. The number of hyperreflective dots (HDs) (p<0.001) and hyperreflective foci (HF) (p = 0.006) was positively correlated with LogMAR BCVA in the univariate analysis. The number of HDs (p = 0.008) remained correlated with LogMAR BCVA in the multivariate analysis. Eyes with an increased number of HF (p = 0.01) were more likely to have hard exudates within a fovea area diameter of 3 mm, while the relationship between the number of HDs and the presence of hard exudates did not reach significance. In the multivariate analysis, the increased level of total cholesterol (TC) (p = 0.004) and the reduced level of serum albumin (p = 0.014) were associated with an increased number of HDs, and the level of serum TC (p = 0.039) was positively associated with the number of HF. ConclusionHyperreflective material may be a predictor for BCVA and serves as a potential biomarker of dyslipidemia in DME. It was postulated that HF are mainly related to hard exudates and HDs are partially associated with microglial cell activation.

Priors-guided convolutional neural network for 3D foveal avascular zone segmentation.

The foveal avascular zone (FAZ) is sensitive to retinal pathological process in the macular fovea area. For the purpose of efficient FAZ 3D quantification, we firstly propose a priors-guided convolutional neural network (CNN) to provide a tailor-made solution for 3D FAZ segmentation for optical coherence tomography angiography (OCTA) images. Location and topology priors are taken into account. The random central crop module is utilized to restrict the region to be processed, while the non-local attention gates are contained in the network to capture long-range dependency. The topological consistency constraint is calculated on maximum and mean projection maps through persistent homology to keep topological correctness of the model's prediction. Our method was evaluated on two OCTA datasets with 478 eyes and the experimental results demonstrate that our method can not only alleviate the over-segmentation prominently but also fit better on the contour of FAZ region.

Microvascular Changes After Conbercept Intravitreal Injection of PDR With or Without Center-Involved Diabetic Macular Edema Analyzed by OCTA.

PurposeTo investigate the intravitreal injection of conbercept as a treatment strategy for proliferative diabetic retinopathy (PDR) with or without center-involved diabetic macular edema (CI-DME) and evaluate its effect on the microvascular changes in the eyes.MethodsIn this prospective study, 43 patients including 29 cases (56 eyes) in CI-DME with PDR patients, and 14 cases (26 eyes) in the non-center involving diabetic macular edema (NCI-DME) with PDR patients were involved in this study. The best corrected visual acuity (BCVA), central retinal thickness (CRT), foveolar avascular zone (FAZ), and macular capillary vessel density (VD) of the superficial retinal capillary plexus (SCP) and deep retinal capillary plexus (DCP) were assessed before and after conbercept treatments for 1, 3, or 6 months.ResultsThe BCVA was significantly increased after conbercept treatment in the eyes of CI-DME patients. After 6 months of treatment with the conbercept, microvascular density of the inferior area in SCP and the central fovea area in DCP increased significantly, regardless of the central fovea involvement. The effect of the conbercept treatment on the VD of NCI-DME was higher than that of CI-DME. Then, after 6 months of treatment, the CRT of patients with CI-DME and NCI-DME were decreased significantly.ConclusionsIn this study, an intravitreal injection of conbercept significantly improved vision, alleviated macular edema in patients with DME. Conbercept treatment also altered the microvascular density in the retina.

One‐year results of photodynamic therapy with chlorin e6‐polyvinylpyrrolidone complex in patients with chronic central serous chorioretinopathy (pilot study)

AbstractPurposeTo investigate efficacy and safety of photodynamic therapy (PDT) with chlorin e6‐polyvinylpyrrolidone (Ce6‐PVP) complex in patients with chronic central serous chorioretinopathy (CSC).MethodsIn this prospective, interventional, single‐centre clinical pilot study included 28 patients (28 eyes) with chronic CSC. Patients received an intravenous infusion of 3 mg/m2 Ce6‐PVP complex (Photolon, Belmedpreparaty pharmaceutical company, Minsk, Belarus) delivered over a period of 10 min. Exactly 15 min after the start of this infusion, a Ocular Mainster (Standard) Focal/Grid contact lens (Ocular Instruments, Bellevue, Washington, USA) was positioned on the eye, the treatment spot was centered using predefined criteria for fluorescein angiography, and PDT was applied using standard parameters (fluency, 50 J/cm2; wavelength, 662 nm; and treatment duration, 83 seconds). The primary objective was decimal best corrected visual acuity (BCVA) at Month 12. The secondary objectives were central retinal thickness (CRT) in fovea area, complete subretinal fluid (SRF) resolution, number of treatment and safety at Month 12.ResultsMean decimal BCVA showed significant increase from 0.6 ± 0.3 to 0.8 ± 0.4 (p = 0.001), mean CRT decreased significantly from 289 ± 72 to 202 ± 48 µm (p = 0.001), comparing baseline and Month 12. During all follow‐up period mean number of PDT treatments was 1.2 ± 0.5. In 77% (20 eyes) were noted complete SRF resolution during observation period. There were no any systemic adverse events and ocular side effects.ConclusionsOur pilot study demonstrates the efficacy and safety of PDT with Ce6‐PVP complex for chronic CSC during the 12‐month follow‐up. This finding provides key insight into developing new practice for treating chronic CSC. Futures studies in larger numbers of patients and with longer follow‐up are planned to further assess the efficacy and safety of PDT with Ce6‐PVP complex for chronic CSC.

Optical coherence tomography angiography characteristics and correlated factors with visual acuity in retinal arterial occlusion.

To reveal the characteristics of vascular changes in retinal arterial occlusion (RAO) using optical coherence tomography angiography (OCTA) and determine the correlated factors with best-corrected visual acuity (BCVA). This retrospective study recruited 54 RAO patients and 27 healthy individuals. Ophthalmic examinations including BCVA and OCTA were performed in all the patients and individuals. The OCTA outcomes were analyzed using SPSS software, and the characteristics of vascular changes and BCVA-related factors were summarized. The vessel density in all areas except fovea of both superficial capillary plexus (SCP) and deep capillary plexus (DCP) was significantly reduced in RAO eyes compared with the fellow eyes and normal control eyes (P < 0.05). The vessel density of DCP in all areas except fovea was significantly reduced in the fellow eyes compared with that in the normal control eyes as well (P < 0.05). The retinal thickness in fovea was significantly increased in RAO eyes compared with that in the fellow eyes and normal control eyes (P < 0.05), without any differences in other areas between the RAO eyes and the other two groups (P > 0.05). The retinal thickness in whole area and retinal thickness in fovea were correlated with BCVA, respectively (whole area: r = 0.295, P = 0.030; fovea: r = 0.322, P = 0.018). OCTA is a fast, noninvasive, and effective examination means for RAO that can display the vascular density and retinal thickness quantitatively and distinctly. RAO patients had reduced vascular density in both eyes and increased foveal retinal thicknessin RAO eyes, showing a correlation with BCVA.

Does ganciclovir exert retinal toxicity after multiple continuous intravitreal injections?

BackgroundThe objective of this study is to report a case of acute retinal necrosis in which abnormalities in visual function did not correspond to retinal anatomical outcomes.Case presentationA 39-year-old female diagnosed with acute retinal necrosis underwent repeated (nine rounds) intravitreal ganciclovir injection (3 mg/0.1 ml) into the left eye, one injection every 2 weeks. During the therapy, the patient noticed her visual acuity declining gradually. The best corrected visual acuity in the left eye was 20/33. The visual field showed massive visual damage. There was no posterior necrotizing involvement, no macular edema or exudation, and only slight abnormity of the interdigitation zone in the fovea area was visible on OCT. Angio-OCT revealed normal capillary density of three retinal capillary and choriocapillaris layers. The visually evoked potential was normal. The photopic single-flash response showed a declined amplitude of a-wave and b-wave. The amplitudes of photopic 30 Hz flicker were decreased. Multifocal electroretinography revealed macular dysfunction.ConclusionGanciclovir-associated photoreceptor damage may induce abnormalities in retinal function in response to multiple continuous intravitreal ganciclovir injections at a relatively high dosage (3 mg/0.1 ml).

Optical coherence tomography: new opportunities for detecting preclinical vision disorders in patients with HIV infection and tuberculosis

The objective of the study: detection of early preclinical manifestations of vision disorders in patients with TB/HIV co-infection using optical coherence tomography (OCT).Subjects and methods. A prospective open-label study was carried out enrolling patients with TB/HIV co-infection (Group 1, n = 19) and patients with pulmonary and extrapulmonary tuberculosis (Group 2, n = 18). In both groups, standard ophthalmological examination and OCT were performed with measurement of the thickness of the choroid and the diameter of upper and lower temporal and nasal arteries and veins, and assessment of arteriovenous coefficient (AVC).Results. In the patients of both groups, the thickness of the choroid in the fovea area decreased in comparison with healthy volunteers (control group, n = 20), however, the decrease in choroid thickness was statistically significantly more pronounced in the patients of Group 1, and this group was also characterized by change in the caliber of retina arteries and veins, which is expressed in a higher AVC.Conclusion. OCT allows early preclinical diagnosis of eye disorders (in the absence of eye complaints) in patients with tuberculosis, including those with concurrent HIV infection. Detection of choroid disorders and AVC changes in such patients allows timely prescription of therapy and prevention of pathological changes from progression.

A novel 3D segmentation approach for extracting retinal layers from optical coherence tomography images.

Accurate segmentation of retinal layers of the eye in 3D Optical Coherence Tomography (OCT) data provides relevant information for clinical diagnosis. This manuscript describes a 3D segmentation approach that uses an adaptive patient-specific retinal atlas, as well as an appearance model for 3D OCT data. To reconstruct the atlas of 3D retinal scan, the central area of the macula (macula mid-area) where the fovea could be clearly identified, was segmented initially. Markov Gibbs Random Field (MGRF) including intensity, spatial information, and shape of 12 retinal layers were used to segment the selected area of retinal fovea. A set of coregistered OCT scans that were gathered from 200 different individuals were used to build a 2D shape prior. This shape prior was adapted subsequently to the first order appearance and second order spatial interaction MGRF model. After segmenting the center of the macula "foveal area", the labels and appearances of the layers that were segmented were utilized to segment the adjacent slices. The final step was repeated recursively until a 3D OCT scan of the patient was segmented. This approach was tested in 50 patients with normal and with ocular pathological conditions. The segmentation was compared to a manually segmented ground truth. The results were verified by clinical retinal experts. Dice Similarity Coefficient (DSC), 95% bidirectional modified Hausdorff Distance (HD), Unsigned Mean Surface Position Error (MSPE), and Average Volume Difference (AVD) metrics were used to quantify the performance of the proposed approach. The proposed approach was proved to be more accurate than the current state-of-the-art 3D OCT approaches. The proposed approach has the advantage of segmenting all the 12 retinal layers rapidly and more accurately than current state-of-the-art 3D OCT approaches.

Macular pigment optical density after panretinal photocoagulation

ABSTRACT Clinical relevance Panretinal photocoagulation, an important treatment method in diabetic retinopathy, can affect macular pigment optical density, which has protective and antioxidant properties. As a result of this effect, the retina may become more sensitive to high‐energy visible light. Background The current study assesses the effect of panretinal photocoagulation treatment on macular pigment optical density, which has essential functions for the retina. Methods In this prospective clinical study, the colour perimetry method was used to measure macular pigment optical density. Thirty‐six eyes of 36 participants with severe non‐proliferative diabetic retinopathy without macular involvement were included in the study. Conventional panretinal photocoagulation treatments were applied at baseline, one month, two months, and at three months to the participants who clinically required this treatment. Macular pigment optical density and retinal thickness measurements were performed at baseline, months one, two, three and six. Results The mean macular pigment optical density reduction in the fovea over the six-months was 0.02 ± 0.02 logarithmic units (p < 0.001). Similarly, the pericentral areas declined by 0.04 ± 0.03 logarithmic units (p < 0.001). Mean central macular thickness and foveal thickness increased by 5.03 ± 5.02 μm and 2.78 (interquartile range 2–4) μm, respectively. In this study, correlation analysis shows that the laser energy applied was significantly and strongly correlated with reductions in macular pigment optical density (for the fovea and pericentral area respectively: r = −0.855, p < 0.001; r = −0.895, p < 0.001). Further, there were significant and strong correlations between the applied laser energy, and central macular thickness and fovea thickness (r = 0.751, p < 0.001; ρ = 0.718, p < 0.001, respectively). Conclusion Panretinal photocoagulation may potentially cause a decrease in macular pigment density in proportion to the laser energy applied.

Does the Foveal Avascular Zone Change in Glaucoma?

The foveal avascular zone (FAZ) - with perimeter and acircularity index (AI) and surrounding vessel density - are measured in glaucomatous eyes in comparison to healthy eyes - with additional subdivision into visual field defects in different locations (central vs. peripheral). The data from 128 eyes were evaluated. Firstly, glaucomatous eyes (n = 74) were compared with healthy eyes (n = 54). In addition, glaucomatous eyes with a central visual field defect (ZGD, n = 19) and eyes with peripheral visual field defect (PGD, n = 34) were differentiated. The FAZ area, its perimeter and roundness, as well as the parafoveal vessel density (VD), were calculated by means of optical coherence tomography angiography in the superficial and deep vascular plexus. Glaucomatous eyes have no significant change in FAZ, its perimeter or the AI compared to healthy eyes. However, dividing the glaucomatous eye by visual field defect reveals that the eyes with a central defect have a significantly larger FAZ than those with a peripheral defect and the perimeter is also significantly larger. The AI shows no significant difference depending on the localisation of visual field defects. The macular/foveal VD is significantly lower in the ZDG group. In glaucoma, the FAZ enlarges when the visual field defect is centralised and VD decreases significantly in the area of fovea.

Re-evaluation of Garden indexes as a criterion for reduction of femoral neck fracture: a cadaveric study

Objective To investigate whether the Garden indexes can serve as a criterion for rotational displacement of femoral neck fracture. Methods Ten cadaveric specimens of healthy human proximal femur were used for this study. They came from 3 males and 2 females who had died at the age from 45 to 70 years old. A Kirschner wire of 2.0 mm in diameter was implanted into the center of the femoral head. Osteotomy was conducted perpendicular to the middle line of the femoral neck. The rotational angles were marked on the distal osteotomy surface. Each cadaveric specimen was rotated sequentially at pronation and supination angles of 0°, 10°, 20°, 30°, 40°, 50°, 70° and 90°, respectively. X-ray images of anterior-posterior and lateral views were taken to record all the rotations of the specimens. Picture Archiving and Communication Systems (PACS) were used to measure the Garden indexes and compare them among anterior-posterior and lateral X-ray films of different pronation and supination angles. Changes in the area of the femoral head fovea at different rotation angles were observed as well. Results There were no significant differences in the auterior-posterior or latera Garden indexes from 0° to pronation or supination 30°, with all the Garden values >155° (P>0.05); from pronation of 40° to pronation of 90°, the Garden indexes were 152.36°±1.41°, 146.04°±1.64°, 143.95°±0.60° and 141.73°±0.60° for anterior-posterior views and 172.54°±0.86°, 168.57°±0.98°, 157.18°±1.17° and 156.47°±1.63° for lateral views, showing a significant difference between rotational angles (P<0.05); from supination of 40° to supination of 90°, the Garden indexes were 151.67°±1.06°, 147.32°±1.82°, 142.77°±0.75° and 139.88°±1.48° for anterior-posterior views and 172.28°±0.79°, 166.76°±1.02°, 155.67°±1.74° and 154.16°±1.27° for lateral views, showing a significant difference between rotational angles (P<0.05). The area of the femoral head fovea decreased gradually with the increase in pronation angle, and increased gradually with the increase in supination angle. Conclusions The Garden indexes cannot serve as an accurate indication of rotational displacement in reduction of femoral neck fracture when the pronation or supination angles ranges from 0° to 30°. Changes in the area of the femoral head fovea can help determine the rotational displacement of the femoral neck fracture. Key words: Femoral neck fractures; Reduction; Garden indexes; Rotational displacement