Ocular biomaterials and the anterior eye

Hydrogels, water swollen polymer matrices, have been utilised in many biomedical applications, as there is the potential to manipulate the properties for a given application by changing the chemical structure of the constituent monomers The eye provides an excellent site to examne the interaction between a synthetic material and a complex biological fluid without invasive surgery. There is a need for the development of new synthetic hydrogels for use in the anterior eye, Three applications of hydrogels in the eye were considered in this thesis. For some patients, the only hope of any visual improvement lies in the use of an artificial cornea, or keratoprosthesis, Preliminary investigations of a series of simple homogeneous hydrogel copolymers revealed that the mechanical properties required to withstand surgery and in eye stresses, were not achieved This lead to work on the development of semi-interpenetrating polymer networks based on the aforementioned copolymers, Manufacture of the device and cell response were also studied. Lasers have been employed in ocular surgery to correct refractive defects. If an irregular surface is ablated, an irregular surface is obtained. A hydrogel system was investigated that could be applied to the eye prior to ablation to create a smooth surface. Factors that may influence ablation rate were explored, Soft contact lenses can be used as a probe to study the interaction between synthetic materials and the biological constituents of tears. This has lead to the development of many sensitive analytical techniques for protein and lipid deposition, one of which is fluorescence spectrophotometry. Various commercially available soft contact lenses were worn for different periods of time and then analysed for protein and lipid deposition using fluorescence spectrophotometry, The influence of water content, degree of ionicity and the lens material on the level and type of deposition was investigated.

Management of allergic conjunctivitis and dry eye

Ocular allergy is a common eye condition encountered in clinical practice. However, little is known how seasonal allergic conjunctivitis (SAC), the most common subtype, is managed in clinical practice. Further, dry eye, another common eye condition, may be misdiagnosed as SAC and vice-versa as they share similar signs and symptoms. In addition, despite the frequent recommendation of non-pharmacological treatments for SAC, evidenceto support their use has not been identified in the scientific literature. The aim of this thesis was therefore to determine the actual diagnosis and management of SAC and dry eye in clinical practice and investigate the efficacy of non-pharmacological treatments for these conditions. The diagnostic and management strategies for SAC and dry eye employed by pharmacy staff are found to be inconsistent with current guidelines and scientific evidence based upon a mystery shopper design. Cluster analysis of tear film metrics in normal and dry eye patients identified several clinically relevant groups of patients that may allow for targeted treatment recommendations. Using a novel environmental chamber model of SAC, the use of artificial tears and cold compresses, either alone or combined is an effective treatment modality for acute and symptomatic SAC, on a par with topical anti-allergic medication, and has been demonstrated for the first time. In addition, eyelid warming therapy with a simple, readily available, seed filled device is an effective method of treating meibomian gland dysfunction (MGD) related evaporative dry eye, perhaps the most common dry eye subtype. A greater focus on ophthalmology must be implemented as part of the formal education and training of pharmacy staff, while greater professional communication between community pharmacists, optometrists and the population they serve is required. Artificial tears and cold compresses may be considered as front line agents for acute SAC by pharmacy staff and optometrists, to whom pharmacological treatment options are limited.