Contact lenses for the treatment of ocular surface diseases.

Contact lens wear is useful in ocular conditions such as high refractive errors, irregular astigmatism, corneal ectasias, corneal dystrophies, post-keratoplasty, post-refractive surgeries, trauma, and ocular surface diseases. The new innovations of highly oxygen-permeable contact lens materials have broadened the applications of contact lens suitability. Therapeutic contact lenses are medically used in the management of a wide variety of corneal conditions and ocular surface diseases. These lenses aid in pain relief, enhance corneal healing, maintain ocular homeostasis, and act as a drug delivery system. Drug delivery applications of contact lenses hold promise for improving topical therapy. The modern rigid gas permeable scleral contact lens provides symptomatic relief in painful corneal diseases such as bullous keratopathy, corneal epithelial abrasions, and erosions. It has been useful in therapeutic management as well as visual rehabilitation by enhancing the ocular surface and protecting the cornea from adverse environmental conditions. This review provides a summary of contact lenses used for the treatment of ocular surface diseases based on the current evidence available in the literature. This can help enhance the understanding and management of ocular surface diseases with respect to contact lens use in our day-to-day ophthalmology practice.

Cataract surgery in ocular surface disease.

Cataract surgery, which is the most widely performed ophthalmic procedure, is usually done in the elderly population, who are also prone to ocular surface disorders. Ocular surface diseases are multifactorial in nature and associated with symptoms and signs such as foreign body sensation, burning, fatigue, photophobia, red or watery eyes, or reduced visual acuity. These include a spectrum of conditions that may be immune or non-immune in nature. Cataract surgery in itself is known to alter the normal ocular surface milieu and cause tear film disturbances which can last up to 6 months post-operatively. These symptoms can be exaggerated in patients with ocular surface diseases. The planning and execution of cataract surgery can also be difficult in patients with associated ocular surface diseases. In this review, we discuss the various aspects of planning and intraoperative modifications to optimize the outcomes of cataract surgery in patients with ocular surface diseases.

Dimensional Stability and Retention Strength of Impressions to Custom Impression Trays Fabricated Using Conventional Method and Additive Technology - An In-vitro Study.

BACKGROUND: 3D printing technology is replacing manual fabrication in all fields. 3D-printed impression trays should be assessed as they could replace conventional impression trays in the future. AIM: In-vitro comparison and evaluation of the dimensional stability and retention strength of impressions to custom impression trays fabricated using conventional method and additive technology. MATERIALS AND METHODS: A maxillary edentulous auto-polymerizing acrylic resin model served as the master model. Two moulds were prepared from the master model in order to obtain 12 casts. One cast was scanned for 3D printing digital light processing (DLP) and fused deposition modelling (FDM) 24 impression trays using polylactic acid (PLA). Twelve casts were used to fabricate light cure impression trays. Polyvinyl-siloxane impressions were made on the master model using 36 impression trays and 18 trays each were used to assess dimensional stability and retention strength. RESULTS: In dimensional stability analysis, one sample t-test revealed a statistically significant difference between each group and the master model followed by a one-way ANOVA. There were significant differences, but the difference was less with FDM trays (P < 0.05). In retention strength analysis, one-way Analysis of variance (ANOVA) revealed statistically significant difference between each group and post-hoc test revealed specific difference, the highest with FDM trays (P < 0.05). CONCLUSION: Dimensional changes were observed at 30 minutes and 72 hours. Lesser dimensional changes were observed when impressions were made using FDM trays followed by DLP and light cure trays. The mean retention strength seen in descending order was FDM, followed by DLP and light cure trays. The best retention strength was noticed when impressions were made using FDM trays.

Mucopolysaccharidosis: A broad review.

Mucopolysaccharidosis (MPS) is a group of genetic disorders with seven types and 13 subgroups which are characterized by an inherent deficiency of the enzymes responsible for the degradation of glycosaminoglycans (GAGs). Defective breakdown of GAG products leads to their widespread accumulation within the lysosomes of various organs involving the eye, central nervous system, skeletal, ocular, nervous, respiratory, cardiac, and the gastrointestinal systems. Clinical spectrum varies from mild systemic and ocular abnormalities with a normal life span to severe phenotype, fatal in the first few months of life. Visual disability due to corneal clouding, retinopathy, and optic nerve involvement causes additional impairment of physical and cognitive functions. Treatment modalities such as bone marrow transplantation and enzyme replacement therapies help in increasing the life span as well as the quality of life of the affected patients. For patients with significant corneal clouding, keratoplasty is the answer. The decision to proceed with keratoplasty is governed by various factors such as the motivation of the patient and his family, other systemic affections and anesthesia concerns. A detailed preoperative counseling should be done regarding the expected visual outcomes in the presence of other ocular comorbidities and the postoperative complication such as graft re-opacification, rejection and glaucoma. Future treatment options such as targeted gene therapy and substrate reduction therapy hold promise to reverse corneal clouding, thereby obviating the need for corneal transplantation. These treatment therapies are still in the experimental stages and human trials are needed to validate their outcomes.

Role of Microscope-Intraoperative Optical Coherence Tomography in Pediatric Keratoplasty: AComparative Study.

PURPOSE: We evaluate the role of microscope-integrated intraoperative optical coherence tomography (i-OCT) in pediatric keratoplasty. DESIGN: Combined prospective and retrospective, comparative, interventional study conducted at the Dr Rajendra Prasad Center for Ophthalmic Sciences in New Dehli, India. METHODS: Seventy-five children ≤16 years of age undergoing planned keratoplasty were divided into 2 groups and compared regarding intraoperative course and postoperative outcome. In group 1 (prospective group, n = 56), preoperative anterior segment visualization was performed clinically, with ultrasound biomicroscopy (UBM) and i-OCT and keratoplasty was commenced under i-OCT microscope. In group 2 (retrospective group, n = 19), a conventional microscope was used during keratoplasty. RESULTS: In group 1, i-OCT, UBM, and clinical examination detected retrocorneal membrane in 10%, 7.5%, and 5% (P = .005), iris adhesions in 62.5%, 57.5%, and 20% (P = .02), iris stump in aniridia 15%, 10%, and 0% (P = .001), shallow central anterior chamber in 22.5%, 22.5%, and 7.5% (P = .003), and shallow peripheral anterior chamber in 65%, 60%, and 17.5% (P = .004) of children, respectively. The use of i-OCT affected intraoperative surgeon decision making in 45% and 33% of cases of anterior and posterior lamellar keratoplasty, respectively. During penetrating keratoplasty, concomitant intraoperative procedures were higher in group 1 than in group 2, namely synechiolysis (19/40 vs 2/15; P = .1), pupilloplasty (4/40 vs 0/15; P = .02), lens extraction (4/40 vs 1/15; P = .5), and anterior vitrectomy (2/40 vs 1/15; P = .4). Postoperative secondary interventions were lower (P = .04) in group 1 (48.21% vs 94.74%). CONCLUSIONS: Anterior segment imaging with i-OCT and UBM immediately before surgery improves the surgical planning of children with corneal opacities. In addition, the use of i-OCT refines intraoperative steps, thereby optimizing the postoperative outcome of pediatric keratoplasty.

Overlap in nitrogen sources and redistribution of nitrogen between trees and grasses in a semi-arid savanna.

A key question in savanna ecology is how trees and grasses coexist under N limitation. We used N stable isotopes and N content to study N source partitioning across seasons from trees and associated grasses in a semi-arid savanna. We also used (15)N tracer additions to investigate possible redistribution of N by trees to grasses. Foliar stable N isotope ratio (δ(15)N) values were consistent with trees and grasses using mycorrhiza-supplied N in all seasons except in the wet season when they switched to microbially fixed N. The dependence of trees and grasses on mineralized soil N seemed highly unlikely based on seasonal variation in mineralization rates in the Kruger Park region. Remarkably, foliar δ(15)N values were similar for all three tree species differing in the potential for N fixation through nodulation. The tracer experiment showed that N was redistributed by trees to understory grasses in all seasons. Our results suggest that the redistribution of N from trees to grasses and uptake of N was independent of water redistribution. Although there is overlap of N sources between trees and grasses, dependence on biological sources of N coupled with redistribution of subsoil N by trees may contribute to the coexistence of trees and grasses in semi-arid savannas.

Elizabethkingia meningoseptica bacteremia in immunocompromised hosts: The first case series from India.

BACKGROUND: Although Elizabethkingia meningoseptica (Chryseobacterium meningosepticum) infections in immunocompromised hosts have been recognised, clinical data detailing these infections remain limited, especially from India. Antimicrobial susceptibility data on E. meningoseptica remain very limited, with no established breakpoints by Clinical and Laboratory Standards Institute (CLSI). The organism is usually multidrug resistant to antibiotics usually prescribed for treating Gram-negative bacterial infections, a serious challenge to the patient and the treating clinicians. MATERIALS AND METHODS: The analysis was done in a tertiary care oncology and stem cell transplant center. Susceptibility testing and identification of E. meningoseptica was done using Vitek auto analyzer. Records of immunocompromised patients with E. meningoseptica bacteremia were analysed from January 2009 to March 2012. RESULTS: A total of 29 E. meningoseptica bacteremia cases were documented between 2009 and 2012. Eleven patients were immunocompromised. Three were post stem cell transplant and one was post cord blood transplant. The mean age of the patients was 48.4 years. Mean Charlson's comorbidity index was 5.7. Four had solid organ malignancies, five had hematological malignancies, and two had lymphoreticular malignancy. Eight patients had received chemotherapy. Mean Apache II score was 18. Mean Pitts score for bacteremia was 4.7. Two were neutropenic (one post SCT, one MDS post chemo) with a mean white blood cell (WBC) count of 450/mm(3) . Ten had a line at the time of bacteremia. Mean duration of the line prior to bacteremia was 8 days. Eight had line-related bacteremia. Three had pneumonia with secondary bacteremia. All received combination therapy with two or more antibiotics which included cotrimoxazole, rifampicin, piperacillin-tazobactam, tigecycline, or cefepime-tazobactam. All the isolates showed in vitro resistance to ciprofloxacin. Five patients died, but a multivariate analysis was not done to calculate the attributable mortality. CONCLUSION: In our study, central line was the commonest risk factor for E. meningosepticum bacteremia, although a multivariate analysis was not done. There has not been much of a change in the susceptibility pattern of these organisms over 3 years, with good susceptibility to piperacillin-tazobactam and cotrimoxazole. Even though uncommon, E. meningoseptica is an important pathogen, especially in immunocompromised hosts with indwelling devices.