Approach to a spontaneously ruptured posterior polar cataract.

A 61-year-old man presented with gradual blurring of vision and glare in both eyes for a couple of years, with worsening of the vision in his right eye over the past 2 months. He had no medical history of note. On clinical examination, his visual acuities were 20/80 in the right eye and 20/30 in the left eye, uncorrected. The cornea was clear, and the anterior chamber (AC) was deep in both eyes. He had bilateral mild nuclear sclerosis with round central onion-ring-like posterior opacities. The opacities measured approximately 2 mm in diameter and were marginally larger in the right eye than in the left eye (Figure 1JOURNAL/jcrs/04.03/02158034-202305000-00018/figure1/v/2023-04-20T184543Z/r/image-tiff). In addition, there were 2 curvilinear lines across the right posterior capsule (PC), one of which passed across the lens opacity (Figure 2JOURNAL/jcrs/04.03/02158034-202305000-00018/figure2/v/2023-04-20T184543Z/r/image-tiff). Fundus examination was normal in both eyes, and the vitreous was clear. Optical coherence tomography (OCT) of the macular and optic nerve in both eyes was normal. The endothelial cell count in both eyes exceeded 2000 cells/mm2. He had been told by a previous ophthalmologist to have bilateral cataracts and was now keen for surgery starting with the right eye. He works as a manager in a large company and is an avid golf player. He is emmetropic and wears spectacles for near work. Optical biometry using predicated posterior corneal astigmatism did not recommend a toric intraocular lens (IOL). He had done his internet research on IOL options and requested trifocal IOLs. What is your surgical plan for right cataract removal? Explain which IOL you would choose to implant.

Human pose tracking in monocular sequence using multilevel structured models.

Tracking human body poses in monocular video has many important applications. The problem is challenging in realistic scenes due to background clutter, variation in human appearance and self-occlusion. The complexity of pose tracking is further increased when there are multiple people whose bodies may inter-occlude. We proposed a three-stage approach with multi-level state representation that enables a hierarchical estimation of 3D body poses. Our method addresses various issues including automatic initialization, data association, self and inter-occlusion. At the first stage, humans are tracked as foreground blobs and their positions and sizes are coarsely estimated. In the second stage, parts such as face, shoulders and limbs are detected using various cues and the results are combined by a grid-based belief propagation algorithm to infer 2D joint positions. The derived belief maps are used as proposal functions in the third stage to infer the 3D pose using data-driven Markov chain Monte Carlo. Experimental results on several realistic indoor video sequences show that the method is able to track multiple persons during complex movement including sitting and turning movements with self and inter-occlusion.

Association analysis of CFH, C2, BF, and HTRA1 gene polymorphisms in Chinese patients with polypoidal choroidal vasculopathy.

PURPOSE: Polypoidal choroidal vasculopathy (PCV) is a major cause of serosanguinous maculopathy in Chinese patients with age-related macular degeneration (AMD). Variants in the CFH and HTRA1/LOC387715 genes are strongly associated with AMD in Caucasians and Chinese. Variants in the C2 and BF genes have been found to confer a significantly reduced risk of AMD. This study was undertaken to determine whether these associations occur in Chinese patients with PCV. METHODS: Patients of Chinese ethnicity with clinically and angiographically diagnosed PCV and normal control subjects were recruited from the Singapore National Eye Centre. Five single-nucleotide polymorphisms (SNPs) in the CFH gene, two each within the C2 and BF genes and two variants located in the LOC387715 and HTRA1 genes, were screened in all patients and control subjects. RESULTS: Seventy-two patients with PCV and 93 normal control subjects were studied. A significant association was noted with CFH variants rs3753394 and rs800292 among the PCV cases (P = 0.0015 and P = 0.0045, respectively). Individuals homozygous for the TT genotype of rs3753394 had a significantly higher risk (P = 0.0076) of PCV (OR = 4.29; 95% CI: 1.47-12.50) than those carrying a single copy of the T allele (P = 0.3210; OR = 1.69; 95% CI: 0.60-4.78), after adjustment for such risk factors as age and sex. The genotype frequencies of rs11200638 and rs10490924 in HTRA1 and LOC387715, respectively, were also found to be significantly different between patients with PCV and normal control subjects (P = 0.00032 and P = 0.003, respectively). The AA genotype of rs11200638 and TT genotype of rs10490924 conferred a 4.9-fold (95% CI: 1.85-12.95) and 4.89-fold (95% CI: 1.85-12.90) increased risk of PCV, respectively, after adjustment for age and sex. The Y402H variant of CFH (rs1061170) and the BF and C2 variants were not significantly different in patients and normal control subjects. CONCLUSIONS: The SNPs rs3753394 and rs800292 of CFH and rs11200638 of HTRA1 are significantly associated with the risk of PCV in Chinese patients.

Development of a 95/5 poly(L-lactide-co-glycolide)/hydroxylapatite and beta-tricalcium phosphate scaffold as bone replacement material via selective laser sintering.

95/5 Poly(L-lactide-co-glycolide) was investigated for the role of a porous scaffold, using the selective laser sintering (SLS) fabrication process, with powder sizes of 50-125 and 125-250 microm. SLS parameters of laser power, laser scan speed, and part bed temperature were altered and the degree of sintering was assessed by scanning electron microscope. Composites of the 125-250 microm polymer with either hydroxylapatite or hydroxylapatite/beta-tricalcium phosphate (CAMCERAM II were sintered, and SLS settings using 40 wt % CAMCERAM II were optimized for further tests. Polymer thermal degradation during processing led to a reduction in number and weight averaged molecular weight of 9% and 12%, respectively. Compression tests using the optimized composite sintering parameters gave a Young's modulus, yield strength, and strain at 1% strain offset of 0.13 +/- 0.03 GPa, 12.06 +/- 2.53 MPa, and 11.39 +/- 2.60%, respectively. Porosity was found to be 46.5 +/- 1.39%. CT data was used to create an SLS model of a human fourth middle phalanx and a block with designed porosity was fabricated to illustrate the process capabilities. The results have shown that this composite and fabrication method has potential in the fabrication of porous scaffolds for bone tissue engineering.

Comparison of drying methods in the fabrication of collagen scaffold via indirect rapid prototyping.

Porous collagen scaffolds with predefined 3-dimesional (3-D) networks of internal channels are fabricated via an indirect rapid prototyping technique. To obtain the scaffolds, two drying methods, namely critical point drying and freeze-drying were investigated. The latter was found to be a more suitable process as it induced less shrinkage and reproduced the design morphology accurately. The resulting scaffold contained internal hollow channels with porous foam-like structure occupying the surrounding volume. The mean diameter of the pores was 180 +/- 60 microm and the channels diameter obtained was measured as 437 +/- 100 microm. The channels were defined and strengthened by a layer of skin due to the process of freeze-drying. These networks of internal channels serve to enhance the mass transport rate through the scaffold and help to increase the depth of cells penetration in the scaffold.

A model-based approach for estimating human 3D poses in static images.

Estimating human body poses in static images is important for many image understanding applications including semantic content extraction and image database query and retrieval. This problem is challenging due to the presence of clutter in the image, ambiguities in image observation, unknown human image boundary, and high-dimensional state space due to the complex articulated structure of the human body. Human pose estimation can be made more robust by integrating the detection of body components such as face and limbs, with the highly constrained structure of the articulated body. In this paper, a data-driven approach based on Markov chain Monte Carlo (DD-MCMC) is used, where component detection results generate state proposals for 3D pose estimation. To translate these observations into pose hypotheses, we introduce the use of "proposal maps," an efficient way of consolidating the evidence and generating 3D pose candidates during the MCMC search. Experimental results on a set of test images show that the method is able to estimate the human pose in static images of real scenes.

Initial Experience With the Wavelight Refractive Suite for Myopic Laser In Situ Keratomileusis.

PURPOSE: The objective of this study was to describe our initial experience with the newest refractive platform, the Wavelight Refractive Suite. DESIGN: This was a consecutive case series of first 50 eyes that underwent myopic laser in situ keratomileusis. METHODS: A total of 50 myopic eyes (28 patients) were included in this study. Uncorrected distance visual acuity, manifest refraction, and keratometry readings were taken preoperatively and 3 months postoperatively. Emmetropia was targeted with an optical zone of 6.5 mm, and flap dimensions were of 130-µm thickness and 9-mm diameter with a superior hinge in all eyes. Flap thickness was measured with optical coherence tomography postoperatively. RESULTS: At 3 months postoperatively, 82% (41/50) of eyes achieved uncorrected distance visual acuity of 6/6 or better, 98% (49/50) achieved 6/9 or better, and all eyes achieved 6/12 or better. Eighty-four percent of eyes were within 0.5 diopter (D) of target of emmetropia, and 98% of eyes were within 1 D. Mean postoperative flap thickness was 124 ± 7.8 µm. CONCLUSIONS: The Wavelight Refractive Suite consisting of the femtosecond laser FS200 and Excimer laser EX500 is the newest integrated refractive surgical platform available and can offer good refractive predictability as shown by the results in our initial 50 myopic eyes.

Improved biocomposite development of poly(vinyl alcohol) and hydroxyapatite for tissue engineering scaffold fabrication using selective laser sintering.

In scaffold guided tissue engineering (TE), temporary three-dimensional scaffolds are essential to guide and support cell proliferation. Selective Laser Sintering (SLS) is studied for the development of such scaffolds by eliminating pore spatial control problems faced in conventional scaffolds fabrication methods. SLS offers good user control over the scaffold's microstructures by adjusting its main processing parameters, namely the laser power, scan speed and part bed temperature. This research focuses on the improvements in the fabrication of TE scaffolds using SLS with powder biomaterials, namely hydroxyapatite (HA) and poly(vinyl alcohol) (PVA). Grinding of as-received PVA powder to varying particle sizes and two methods of mixing are investigated as the preparation process to determine a better mixing method that would enhance the mixture homogeneity. Suitable sintering conditions for the improved biocomposite are then achieved by varying the important process parameters such as laser power, scan speed and part bed temperature.SLS fabricated samples are characterized using Fourier Transform Infrared Spectrometer (FTIR) and Scanning Electron Microscope (SEM). FTIR results show that the grinding and sintering processes neither compromise the chemical composition of the PVA nor cause undue degradation. Visual analysis of the grinding, powder mixing and sintering effect are carried out with SEM. The SEM observations show improvements in the sintering effects. The favorable outcome ascertains PVA/HA biocomposite as a suitable material to be processed by SLS for TE scaffolds.

Optical coherence tomography evidence of rapid progression from vitreomacular traction to full thickness macular hole.

The authors present a case of a patient with idiopathic vitreomacular traction who subsequently developed a full thickness macular hole 3 weeks following the onset of metamorphopsia. Vitreomacular traction is a well described phenomenon and has been known to resolve spontaneously and in this patient the conservative approach was adopted initially. However, she progressed rapidly to a full thickness macular hole and therefore, the authors recommend close monitoring of such patients with a view to early vitrectomy to prevent progressive morbidity.

Optic disc laceration with combined retinal artery and vein occlusion following penetrating injury.

Ocular trauma is a major cause of unilateral blindness and male adults in the working age group have been found to have higher rates of ocular injury. A case of a work-related penetrating ocular trauma with an intraocular foreign body causing an optic disc laceration and consequently a combined retinal arterial and venous occlusion is presented. The patient did not recover useful vision despite early surgical intervention. This case highlights an unusual sequelae following penetrating ocular trauma as well as the importance of safety eyewear for individuals in high-risk occupations.

Optic nerve toxoplasmosis and orbital inflammation as initial presentation of AIDS.

PURPOSE: To report a case of toxoplasmosis with optic nerve and orbital involvement as the initial presentation of HIV infection. METHOD: Case report. RESULTS: A 46-year-old zookeeper, who had had right central retinal vein occlusion (CRVO) 2 weeks previously, presented with painless lid and conjunctival swelling and profound visual loss in his right eye (RE). Examination revealed no light perception (NLP) RE with axial proptosis and ocular motility restriction; fundal examination revealed a clinical picture of an ischaemic CRVO. MRI of the brain and orbit showed ring-enhancing targetoid lesions in the brain and inflammatory changes in the right optic nerve, extraocular muscles and orbital fat. He was subsequently found to be HIV positive and had positive toxoplasma IgG serology. CONCLUSIONS: Immunocompromised individuals have an increased likelihood for more severe and atypical presentations; this highlights the need for increased index of suspicion for HIV infection as ocular or orbital disease may be the first manifestation of life-threatening systemic toxoplasmosis.