Optic Edge Research Articles

IMPACTS OF POSTERIOR STAPHYLOMA ON PARAPAPILLARY MICROVASCULATURE AND ATROPHY IN HIGH MYOPIC EYES: A Matched Cohort Study With Optical Coherence Tomography Angiography.

To evaluate the impacts of the different types of posterior staphyloma (PS) in high myopia on parapapillary microvasculature and parapapillary atrophy (PPA, i.e., γ-zone and δ-zone) with optical coherence tomography angiography. This cross-sectional study included 152 high myopic eyes (152 participants) with γ-zone. After matching, high myopic eyes were stratified into PS (n = 33) and non-PS (n = 33) groups. Posterior staphyloma types, parapapillary microvasculature characteristics, the prevalence of nonjuxtapapillary microvasculature dropout, the longest radial width from the optic disk edge to retinal pigment epithelial atrophy edge (PPA width), γ-zone, and δ-zone with changes in visual field, and best-corrected visual acuity were evaluated and analyzed. According to Curtin classification, we identified five types of PS included: primary Types I, II, III, and compound Types VII, and IX. Eyes with Type II showed a higher optic disk tilted ratio and larger PPA width compared with other primary PS. Subjects with Type IX were the oldest. Eyes with Types VII and IX had wider γ-zone and δ-zone, worse visual field outcomes, poorer best-corrected visual acuity, and a higher incidence of non-juxtapapillary microvasculature dropout compared with primary PS. Choroidal and intrascleral vessels were associated with nonjuxtapapillary microvasculature dropout and were located near or connected to the circle of Zinn-Haller. Eyes with high myopia and PS show wider PPA, affecting the γ-zone and δ-zone, and are at a higher risk of developing nonjuxtapapillary microvasculature dropout. Specifically, eyes with PS Types VII and IX are more susceptible to visual field damage and decreased best-corrected visual acuity. These results highlight the importance of the impact of PS on parapapillary microvasculature and PPA in high myopia.

Posterior capsule opacification with two similar-design hydrophobic acrylic intraocular lenses: 3-year results of a randomized controlled trial.

To compare intraindividually the incidence and intensity of posterior capsule opacification (PCO) and Nd:YAG capsulotomy rates between 2 similar open-loop single-piece hydrophobic acrylic intraocular lenses (IOLs) differing slightly in their particular material, optic surface, and sharp posterior edge design over a period of 3 years. Department of Ophthalmology, Medical University Vienna, Vienna, Austria. Randomized, prospective, patient-masked and examiner-masked clinical trial with intraindividual comparison. 100 patients randomly received a Vivinex XY1 IOL in 1 eye and a Clareon CNA0T0 IOL in the fellow eye. The amount of PCO (score 0 to 10) was assessed subjectively and objectively with digital retroillumination pictures using automated image analysis software (Automated Quantification of After-Cataract). Corrected distance visual acuity and the presence of glistenings, subjective visual symptoms, and Nd:YAG laser capsulotomy rate were noted. 67 of 100 patients were available for the 3-year follow-up examination. The objective PCO score of the Vivinex XY1 IOLs was 1.0 ± 1.0 compared with the PCO score of 1.5 ± 1.2 for the Clareon CNA0T0 IOLs ( P < .001). 7.5% of patients had a Nd:YAG capsulotomy in the Vivinex XY1 eye, and 9.0% had a capsulotomy in the Clareon CNA0T0 eye ( P = 1.0). Both hydrophobic acrylic IOLs showed low PCO and YAG rates with a small but significant favor of the Vivinex XY1 IOL compared with the Clareon CNA0T0 IOL. The interaction of various factors such as hydrophobic material, smooth optic surface, and sharp posterior optic edge is the major key for PCO prevention. NCT04369482.

Negative and positive dysphotopsia

Dysphotopsia are responsible for complaints of that small percentage of pseudophakic subjects who are not satisfied with their vision. They are divided into negative and positive. Positive dysphotopsia (PD) are described by patients as glare, light streaks, light arcs, flashes of light, and starbursts produced by an external light source, whereas negative dysphotopsia (ND) is a dark temporal peripheral arc‐shaped shadow or line.PD are related to the nature of the inserted intraocular lens (IOL). The incidence rate of PD at 1 year after cataract surgery is 0.2–2.2%, and there have been no reports of PD in intraocular surgeries other than cataract surgery to date. The cause of ND is unknown, and many concepts trying to explain its pathophysiology were proposed, including a small pupil, an axial space behind the iris, and a sharp optic edge, the increased angle kappa, the nasal location of the pupil relative to the optical axis, with in‐the‐bag IOLs (and not in ciliary sulcus‐, anterior chamber‐, or scleral suture‐fixated IOLs), and a correlation with coverage of the anterior capsule edge, interaction between the anterior capsulorhexis with the intraocular lens, shorter eyes and a higher implanted IOL power, position of the haptic, and neuroadaptive component.

Bilateral Blindness as an Initial Finding of Occipital Lobes Meningioma Metastated from Lung Cancer

Introduction: Meningioma may increase intracranial pressure (ICP) and cause papilledema, which results bilateral blindness. Since elevated ICP is thought to be caused by an underlying condition, immediate neuroimaging is required to look into the possibility of papilledema. Patients with intracranial tumour sometimes being consulted to ophthalmologist with ocular problems as their complaint. The purpose of this report is to describe a case of papilledema as an initial finding of occipital lobes intracranial tumor metastated from lung cancer. Case presentation: A female, 50-year-old patient being consulted from the ward with chief complaint bilateral visual loss gradually worsening in the last three months. Further history taking revealed other symptoms including relapsing headache since a year ago. Patient also came to the ophthalmologist a year ago and get examinated because of the headache and the examination result is only refraction disorder. Patient had decrease of consciousness and started coughing with massive sputum production since a week ago before she is admitted to the hospital. Patient was undergone Lung CT scan, a large mass was found in left lung, then she is diagnosed with lung cancer. Before that she never have any complaints about shortness of breath and chronic cough. The visual acuity on both eyes were already no light perception at the initial visit. Anterior segment was calm but the pupil was mid dilatation with no light reflexes. Fundus examination revealed papilledema, the optic nerve heads edges was blurred. Intraocular pressures were 12 mmHg. A MRI was performed 3 months before the patient got admitted to the hospital and revealed a massive solid mass in the left occipital lobe (approx AP 4 x LL 5 x CC 5.5 cm). Radiological reading suggested a meningioma. The patient was immediately referred to pulmonologist, neurologist, together with surgical neurology unit. Conclusion: A patient with slow growing intracranial tumour may come quite late to seek medical attention since the symptoms are very mild and bearable. When being consulted, the visual acuity is already no light perception. Ophthalmologist must be aware and consider the metastases of lung cancer into intracranial tumour as a cause of visual loss and therefore not to delay its management.

Monte-Carlo simulation of a thick lens IOL power calculation.

The purpose of this Monte-Carlo study is to investigate the effect of using a thick lens model instead of a thin lens model for the intraocular lens (IOL) on the resulting refraction at the spectacle plane and on the ocular magnification based on a large clinical data set. A pseudophakic model eye with a thin spectacle correction, a thick cornea (curvatures for both surfaces and central thickness) and a thick IOL (equivalent power PL derived from a thin lens IOL, Coddington factor CL (uniformly distributed from -1.0 to 1.0), either preset central thickness LT = 0.9 mm (A) or optic edge thickness ET = 0.2 mm, (B)) was set up. Calculations were performed on a clinical data set containing 21 108 biometric measurements of a cataractous population based on linear Gaussian optics to derive spectacle refraction and ocular magnification using the thin and thick lens IOL models. A prediction model (restricted to linear terms without interactions) was derived based on the relevant parameters identified with a stepwise linear regression approach to provide a simple method for estimating the change in spectacle refraction and ocular magnification where a thick lens IOL is used instead of a thin lens IOL. The change in spectacle refraction using a thick lens IOL with (A) or (B) instead of a thin lens IOL with identical power was within limits of around ±1.5 dpt when the thick lens IOL was placed with its haptic plane at the plane of the thin lens IOL. In contrast, the change in ocular magnification from considering the IOL as a thick lens instead of a thin lens was small and not clinically significant. This Monte-Carlo simulation shows the impact of using a thick lens model IOL with preset LT or ET on the resulting spherical equivalent refraction and ocular magnification. If IOL manufacturers would provide all relevant data on IOL design data and refractive index for all power steps, this would make it possible to perform direct calculations of refraction and ocular magnification.

One-Phototransistor-One-Memristor Array with High-Linearity Light-Tunable Weight for Optic Neuromorphic Computing.

The recent advances in optic neuromorphic devices have led to a subsequent rise in use for construction of energy-efficient artificial-vision systems. The widespread use can be attributed to their ability to capture, store, and process visual information from the environment. The primary limitations of existing optic neuromorphic devices include nonlinear weight updates, cross-talk issues, and silicon process incompatibility. In this study, a highlylinear, light-tunable, cross-talk-free, and silicon-compatible one-phototransistor-one-memristor (1PT1R) optic memristor is experimentally demonstrated for the implementation of an optic artificial neural network (OANN). For optic image recognition in the experiment, an OANN is constructed using a 16×3 1PT1R memristor array, and it is trained on an online platform. The model yields an accuracy of 99.3% after only ten training epochs. The 1PT1R memristor, which shows good performance, demonstrates its ability as an excellent hardware solution for highly efficient optic neuromorphic and edge computing.

Unsupervised video object segmentation: an affinity and edge learning approach

This paper presents a new approach, called TMNet, to solve unsupervised video object segmentation (UVOS) problem. The UVOS is still a challenging problem as prior methods suffer from issues like generalization errors in unseen test videos, over reliance on optic flow, and capturing fine details at object boundaries. These issues make the UVOS an ill-defined problem, particularly in presence of multiple objects. Our focus is to constrain the problem and improve the segmentation results by fusion of multiple available cues such as appearance and motion, as well as image and flow edges. To constrain the problem, instead of predicting segmentation directly, we predict affinities between neighbouring pixels for being part of the same object and cluster those to obtain category agnostic segmentation. To further improve the segmentation, we fuse multiple-sources of information through a novel Temporal Motion Attention (TMA) module that uses neural attention to learn powerful spatio-temporal features. In addition, we also design an edge refinement module (using image and optic flow edges) to refine and improve the accuracy of object segmentation boundaries. The overall framework is capable of segmenting and finding accurate objects’ boundaries without any heuristic post processing. This enables the method to be used for unseen videos. Experimental results on challenging DAVIS16 and multi object DAVIS17 datasets show that our proposed TMNet performs favorably compared to the state-of-the-art methods without post processing.

Comparison of age-related vascular changes in the optic disc of patients with diabetes, with glaucomatous and non-glaucomatous features

ObjectiveTo identify age-related vascular changes in the optic discs of patients with diabetes with and without signs of glaucoma.Methods and analysisA total of 2153 eyes of 1797 patients with diabetes...

Study on radar scattering characteristics of double S-shaped nozzles with different aspect ratio

To study the radar scattering characteristics of dual S-bend nozzles with different exit aspect ratios, the iterative physical optic method (IPO) method and equivalent edge currents method (EEC) method were combined to build a code that can be used to solve the electromagnetic scattering field of the nozzle. The reliability of the method has been verified by comparing the reference data. Then, the forward and back-forward IPO and ray tracing methods are used to reduce the calculation time. CFD method is used to calculate and analyse the influence of aspect ratio double S-shaped nozzle on aerodynamic performance. The thrust coefficient and the total pressure recovery coefficient of the double S-shaped nozzle will gradually decrease with the increase of the aspect ratio. the influence of the aspect ratio on the radar scattering characteristics of the dual S-shaped nozzle under the C-band was simulated by the IPO and the results were discussed.it is obtained that the RCS average value in the range of −40°~40° gradually decreases with the increase of the aspect ratio. Under the vertical polarization mode of the pitch detection plane, the average RCS of the AR6 model is 52.8% lower than that of the AR3 model, while it is reduced by 11.0% in the horizontal polarization mode, which has better stealth performance.

DBFU-Net: Double branch fusion U-Net with hard example weighting train strategy to segment retinal vessel.

BackgroundMany fundus imaging modalities measure ocular changes. Automatic retinal vessel segmentation (RVS) is a significant fundus image-based method for the diagnosis of ophthalmologic diseases. However, precise vessel segmentation is a challenging task when detecting micro-changes in fundus images, e.g., tiny vessels, vessel edges, vessel lesions and optic disc edges.MethodsIn this paper, we will introduce a novel double branch fusion U-Net model that allows one of the branches to be trained by a weighting scheme that emphasizes harder examples to improve the overall segmentation performance. A new mask, we call a hard example mask, is needed for those examples that include a weighting strategy that is different from other methods. The method we propose extracts the hard example mask by morphology, meaning that the hard example mask does not need any rough segmentation model. To alleviate overfitting, we propose a random channel attention mechanism that is better than the drop-out method or the L2-regularization method in RVS.ResultsWe have verified the proposed approach on the DRIVE, STARE and CHASE datasets to quantify the performance metrics. Compared to other existing approaches, using those dataset platforms, the proposed approach has competitive performance metrics. (DRIVE: F1-Score = 0.8289, G-Mean = 0.8995, AUC = 0.9811; STARE: F1-Score = 0.8501, G-Mean = 0.9198, AUC = 0.9892; CHASE: F1-Score = 0.8375, G-Mean = 0.9138, AUC = 0.9879).DiscussionThe segmentation results showed that DBFU-Net with RCA achieves competitive performance in three RVS datasets. Additionally, the proposed morphological-based extraction method for hard examples can reduce the computational cost. Finally, the random channel attention mechanism proposed in this paper has proven to be more effective than other regularization methods in the RVS task.

Contributed Session I: Negative dysphotopsia evaluation using individualized eye models

Building on our previously communicated results, the current study evaluates the predictive ability of individualized eye models to localize negative dysphotopsia (ND) in the peripheral field of view (PFoV) In a prospective study conducted at Hanusch Hospital, Vienna, Austria, post-operative biometrical data were acquired from five patients implanted with monofocal IOLs and with ND complaints. A Harms tangent screen subjective method was used to localize in PFoV the perceived shadow (HvF). For computing theoretical retinal irradiance maps, individualized Liou-Brennan (non)-sequential eye models were generated using the acquired biometrical data. Mean axial length was 22.83 (21.05 - 24.80) mm, mean IOL power 24.4 (20.5 - 30.0) D, mean IOL tilt -1.86 (-6.21 - 2.96) degrees and mean decentration 0.16 (-0.27 - 0.44) mm. Average residual astigmatism difference between theoretical and measured data was 0.49 (0.02 - 0.97) D. Aligned with HvF data, the irradiance maps localized ND in the peripheral visual field up to 85 degrees. Previously presented theoretical results evidenced that in identical biometrical conditions, IOLs from different manufacturers with similar mechanical platforms but different optic edge designs are characterized by comparable ND profiles with the peripheral location of the shadows between 69 and 76 degrees. Further expanding the utilization of these eye models, the current results demonstrate their clinical relevance in terms of PFoV localization of ND.

Interocular asymmetry in distribution of leaks in central serous chorioretinopathy.

To study interocular asymmetry in distribution of leaks in central serous chorioretinopathy (CSC). Patients with unilateral CSC were included in this retrospective multicenter study. All patients received multimodal imaging. The prevalence of leaks within 1 disk diameter (DD) peripapillary area and the mean shortest distance between a leak and the optic disk edge was analyzed for the right and left eyes separately based on FA images. Clinical and morphological characteristics were collected and compared between eyes with a peripapillary leak and eyes with a leak elsewhere. In total, 152 eyes (77 right eyes and 75 left eyes) of 152 patients (128 males and 24 females) with a mean age of 45.2 ± 9.8years were included. The mean distance from the leak to the edge of the optic disk was statistically significantly lower (p = 0.0003), and the prevalence of the leaks within the 1 DD-peripapillary area was higher in the left eye than in the right eye (32.1% versus 10.7%, respectively, p = 0.0017). The eyes with a peripapillary leak had a longer duration of the disease (p < 0.05), a wider area of retinal pigment epithelium alteration (p < 0.001), and a higher prevalence of outer retinal atrophy (p < 0.001) compared to the eyes with a leak elsewhere. The left eye showed closer location of the leak to the optic disk edge and higher prevalence of leaks within the peripapillary area. The cases with peripapillary leak commonly demonstrated characteristics of chronic CSC despite relative preservation of visual acuity.

Long-Term Clinically Significant Posterior Capsular Opacification Development Pattern in Eyes Implanted with an Aspheric Monofocal Intraocular Lens with a Square Optic Edge.

Purpose To analyse the posterior capsular opacification (PCO) development pattern in the long term in eyes implanted with a monofocal intraocular lens (IOL) with a square edge all around the optic. Methods Longitudinal retrospective study is data analyzed from a total of 7059 eyes from 4764 patients (mean age: 75.8 years) undergoing cataract surgery with implantation of an aspheric monofocal IOL (Bi-Flex HL 677AB/677P, Medicontur, Budapest, Hungary). These data were retrospectively collected using the electronic medical record of the hospitals involved. Nd : YAG capsulotomy rates were calculated per year during a follow-up of more than 10 years. The Kaplan–Meier analysis was used to establish the transparent capsule survival rate. Results The Nd : YAG capsulotomy rate increased from 1.1% at 1 year postoperatively to 17.2% at 5 years after surgery. No significant differences were found between eyes with and without capsulotomy in terms of age (p = 0.202), gender (p = 0.061), type of anaesthesia used (p = 0.128), and presence of conditions such as hard cataract (p = 0.111) or pseudoexfoliation (p = 0.137). IOL power was significantly lower in those eyes of patients requiring Nd : YAG capsulotomy during the follow-up (p < 0.001). Significantly more eyes implanted with the preloaded model of the IOL required capsulotomy (p < 0.001). Mean survival time and rate were 9.38 years and 85.9%, respectively. Conclusions Most eyes undergoing cataract with implantation of the Bi-Flex IOL do not develop a clinically significant PCO requiring Nd : YAG capsulotomy in the long term. IOL material and design may be the main factors accounting for this finding.

Intraocular lens optic edge design for the prevention of posterior capsule opacification after cataract surgery.

Intraocular lens optic edge design for the prevention of posterior capsule opacification after cataract surgery.

A high resolution representation network with multi-path scale for retinal vessel segmentation

Background and objectives: Automatic retinal vessel segmentation (RVS) in fundus images is expected to be a vital step in the early image diagnosis of ophthalmologic diseases. However, it is a challenging task to detect the retinal vessel accurately mainly due to the vascular intricacies, lesion areas and optic disc edges in retinal fundus images. Methods: In this paper, we propose a high resolution representation network with multi-path scale (MPS-Net) for RVS aiming to improve the performance of extracting the retinal blood vessels. In the MPS-Net, there exist one high resolution main road and two lower resolution branch roads where the proposed multi-path scale modules are embedded to enhance the representation ability of network. Besides, in order to guide the network focus on learning the features of hard examples in retinal images, we design a hard-focused cross-entropy loss function. Results: We evaluate our network structure on DRIVE, STARE, CHASE and synthetic images and the quantitative comparisons with respect to the existing methods are presented. The experimental results show that our approach is superior to most methods in terms of F1-score, sensitivity, G-mean and Matthews correlation coefficient. Conclusions: The promising segmentation performances reveal that our method has potential in real-world applications and can be exploited for other medical images with further analysis.

Effect of ECG-gating Retinal Photographs on Retinal Vessel Caliber Measurements in Subjects with and without Type 2 Diabetes

ABSTRACT Purpose/Aim of this study: Retinal vessel caliber is an independent risk marker of cardiovascular disease risk. However, variable mechanical delays in capturing retinal photographs and cardiac cycle-induced retinal vascular changes have been shown to reduce the accuracy of retinal vessel caliber measurements, but this has only ever been investigated in healthy subjects. This cross-sectional study is the first study to investigate this issue in type 2 diabetes. The aim of this study was to determine whether ECG-gating retinal photographs reduce the variability in retinal arteriolar and venular caliber measurements in controls and type 2 diabetes. Materials and Methods: Fifteen controls and 15 patients with type 2 diabetes were arbitrarily recruited from Westmead Hospital, Sydney, Australia. A mydriatic fundoscope connected to our novel ECG synchronization unit captured 10 ECG-gated (at the QRS) and 10 ungated digital retinal photographs of the left eye in a randomized fashion, blinded to study participants. Two independent reviewers used an in-house semi-automated software to grade single cross-sectional vessel diameters across photographs, between 900 and 1800 microns from the optic disc edge. The coefficient of variation compared caliber variability between retinal arterioles and venules. Results: Our ECG synchronization unit reported the smallest time delay (33.1 ± 48.4 ms) in image capture known in the literature. All 30 participants demonstrated a higher reduction in retinal arteriolar (ungated: 1.02, 95%CI 0.88–1.17% vs ECG-gated: 0.39, 95%CI 0.29–0.49%, p < .0001) than venular (ungated 0.62, 95%CI 0.53–0.73% vs ECG-gated: 0.26, 95%CI 0.19–0.35%, p < .0001) coefficient of variation by ECG-gating photographs. Intra-observer repeatability and inter-observer reproducibility analysis reported high interclass correlation coefficients ranging from 0.80 to 0.86 and 0.80 to 0.93 respectively. Conclusion: ECG-gating photographs at the QRS are recommended for retinal vessel caliber analysis in controls and patients with type 2 diabetes as they refine measurements.

Perfect anterior capsulorhexis using a dented cystitome.

We describe a novel intraoperative technique of measuring and creating an adequate size continuous curvilinear capsulorhexis (CCC) in phacoemulsification, using a dented cystitome as the ruler. A pair of curved tenotomy scissors is used to create a dent on the cystitome at a distance of 2.5 mm length (i.e., half of the desired approximate capsulorhexis diameter). The dented cystitome is used as a guide for making a CCC of approximately 5 mm diameter, which is considered adequate for phacoemulsification. This method of measuring the capsulorhexis helps in achieving a well centered and stable intraocular lens with a 360° overlap of the optic edge by the anterior capsular rim in the postoperative period. Using a dented cystitome for capsulorhexis mandates reliable and consistent results in the hands of the novice as well as the experienced surgeons.

Assessment of intraocular lens/capsular bag biomechanical interactions following cataract surgery in a human in vitro graded culture capsular bag model

Intraocular lenses (IOLs) are implanted during cataract surgery. For optimum results, stable positioning of the IOL in the capsular bag is important. Wound-healing events following cataract surgery lead to modification of the capsular bag and secondary visual loss due to posterior capsule opacification. At present, it is unclear how these biological events can affect stability of the IOL within the capsular bag. In the present study, a human in vitro graded culture capsular bag model was the experimental system. Capsulorhexis and lens extraction performed on human donor eyes generated suspended capsular bags (5 match-paired experiments). Preparations were secured by pinning the ciliary body to a silicone ring and maintained in 6 mL of medium for 84 days using a graded culture system: days 1–3, 5% human serum and 10 ng/mL transforming growth factor β (TGFβ2); days 4–7, 2% human serum and 1 ng/mL TGFβ2; days 8–14, 1% human serum and 0.1 ng/mL TGFβ2; days 15–84, serum-free Eagle's minimum essential medium (EMEM). A CT LUCIA 611PY IOL was implanted in all preparations. Quantitative measures were determined from whole bag images captured weekly. Images were registered using FIJI and analysed in ImageJ to determine capsular bag area; distortion; angle of contact; haptic stability; capsulorhexis area; and a fusion footprint associated with connection between the anterior and posterior capsules. Cell coverage and light scatter were quantified at end-point. The transdifferentiation marker, α-SMA was assessed by immunocytochemistry. Immediately following surgery, distortion of the capsular bag was evident, such that a long axis is generated between haptics relative to the non-haptic regions (short axis). The angle of contact between the haptics and the peripheral bag appeared inversely correlated to capsular bag area. Growth on the peripheral posterior capsule was observed 1 week after surgery and beneath the IOL within 1 month. As coverage of the posterior capsule progressed this was associated with matrix contraction/wrinkles of both the central posterior capsule and peripheral capsular bag. Cells on the central posterior capsule expressed αSMA. Fusion footprints formed in non-haptic regions of the peripheral bag and progressively increased over the culture period. Within and at the edge of the fusion footprint, refractive structures resembling lens fibre cells and Elschnig's pearls were observed. Cell attachment to the IOL was limited. An impression in the posterior capsule associated with the CT LUCIA 611PY optic edge was evident; cell density was much greater peripheral to this indent. Wound-healing events following surgery reduced capsular bag area. This was associated with the long/short axis ratio and angle of contact increasing with time. In summary, we have developed a human capsular bag model that exhibits features of fibrotic and regenerative PCO. The model permits biomechanical information to be obtained that enables better understanding of IOL characteristics in a clinically relevant biological system. Throughout culture the CT LUCIA 611PY appeared stable in its position and capsular bag modifications did not change this. We propose that the CT LUCIA 611PY optic edge shows an enhanced barrier function, which is likely to provide better PCO management in patients.

Power profiles of centre-distance multifocal soft contact lenses.

Centre-distance multifocal contact lenses (MFCLs) for myopia control are thought to slow myopia progression by providing both clear foveal vision and myopic defocus. Characterising the power profile of lenses is important to understanding their possible effects on retinal defocus when worn. The power profiles of three commercially available MFCLs were determined. Three centre-distance MFCL designs were studied: Biofinity Multifocal D +2.50 add (comfilcon A), Proclear Multifocal D +2.50 add (omafilcon A), and NaturalVue Multifocal (etafilcon A). Two lenses each in power from -1.00D to -6.00D in 1D steps were stored in ISO 18369-3:2017 standard phosphate buffered saline for 24h. Optical power profiles were measured in a wet cell with the SHSOphthalmic profiler accounting for centre thickness and manufacturer-reported material refractive index. Sagittal power maps from the SHSOphthalmic were exported, and custom MATLAB code was used to generate power profiles by averaging along the vertical and horizontal meridians. One-way anova with Tukey's HSD post-hoc t-tests were used to analyse maximum add power by lens design. Plus power increased out from the lens centre for all three MFCLs. Power profiles of Biofinity D and Proclear D MFCLs show three distinct areas within the optic zone; the distance zone (from lens centre to about 1.6mm radius), intermediate zone (about 1.6mm radius to 2.1mm) and near zone (about 2mm radius to 4mm). For NaturalVue MFCLs, plus power starts increasing almost immediately from the lens centre, reaching maximum measured mean plus power at a radius of 2.7mm. From 2.7mm to 3.0mm, there was a decrease in plus power, which was then generally maintained out to the optic zone edge. Across all lens powers, maximum add power was highest with the NaturalVue MFCL (+3.32±0.44D), then Proclear D (+1.84±0.28D) and Biofinity D (+1.47±0.34D) MFCLs (all p<0.04). Add power peaked at different locations for different lens powers and designs. Power profiles of MFCLs vary based on lens design and power. These power profiles are consistent with reported myopic and hyperopic changes in peripheral refraction with MFCLs and provide some explanation for reported differences in peripheral refraction with these MFCLs. Further work is needed to determine whether these power profile differences influence myopia progression.

A COMPARISION OF POSTERIOR CAPSULAR OPACITY FORMATION UPTO 1 YEAR IN PATIENTS WITH SMALL INCISION CATARACT SURGERY WITH FOLDABLE INTRAOCULAR LENS AND PHACOEMULSIFICATION WITH THE SAME INTRAOCULAR LENS

Introduction: Cataract is most common cause of curable blindness worldwide and cataract surgery is most common procedure performed in ophthalmology. Posterior capsular opacification (PCO) is most common complication after cataract surgery which is usually treated with Neodymium-doped: Yttrium Garnet (Nd:YAG) laser posterior capsulotomy or occasionally with a surgical capsulotomy. The incidence and severity of PCO correlates to the type of surgical technique, IOL optic edge designs and IOL materials. Material and Methods: 70 eyes of 64 patients operated for age related cataract were studied in this prospective interventional study. Phacoemulsification was done in 35 eyes and SICS in 35 eyes with hydrophobic single piece biconvex foldable intraocular lens. Patients were followed up at 1, 3, 6, 9 and 12 months for the development of PCO. Clinically significant PCO (loss of 2 or more lines of Snellen’s visual acuity chart) was treated with Nd:YAG laser capsulotomy. Results: The overall incidence of PCO was 22.85%. Amongst the patients who developed PCO, SICS and phacoemulsification was performed in 62.5% and 37.5% patients respectively. Result was statistically significant with p value &lt;0.05 using z test. On first postoperative day, patients operated with phacoemulsification had better visual acuity than SICS. Conclusion: Phacoemulsification can provide early and better visual outcome than SICS and has lower incidence of PCO formation which may be due to difference in irrigation and aspiration and less disruption of blood aqueous barrier than SICS. PCO can be reduced by atraumatic surgery and thorough cortical clean up and capsular polishing.