It is sometimes overlooked that ecotourism is a highly consumer-centered activity, and that environmental conservation is a means to further economic growth.Although ecotourism is intended for small groups, even a modest increase in population, however temporary, puts extra pressure on the local environment and necessitates the development of additional infrastructure and amenities. The construction of water treatment plants, sanitation facilities, and lodges come with the exploitation of non-renewable energy sources and the utilization of already limited local resources. The conversion of natural land to such tourist infrastructure is implicated in deforestation and habitat deterioration of butterflies in Mexico and squirrel monkeys in Costa Rica. In other cases, the environment suffers because local communities are unable to meet the infrastructure demands of ecotourism. The lack of adequate sanitation facilities in many East African parks results in the disposal of campsite sewage in rivers, contaminating the wildlife, livestock, and people who draw drinking water from it.Aside from environmental degradation with tourist infrastructure, population pressures from ecotourism also leaves behind garbage and pollution associated with the Western lifestyle. An example of this is seen with ecotourism in Antarctica. Since it is such a remote location, it takes a lot of fuel to get there; resulting in ships producing large pollution through waste disposal and green house gas emissions. Additionally, there is a potential for oil spills from damaged ships traversing through aggressive waters filled with natural obstacles such as icebergs.
Curvatural: Curvatural hypermetropia occur when curvature of lens or cornea is flatter than normal. About 1 mm increase in radius of curvature results in 6 diopters of hypermetropia. Cornea is flatter in microcornea and cornea plana. Index: Age related changes in refractive index (cortical sclerosis) can cause hypermetropia. Another cause of index hypermetropia is diabetes. Occasionally, mild hypermetropic shift may be seen in association with cortical or subcapsular cataract also. Positional: Positional hypermetropia occur due to posterior dislocation of Lens or IOL. It may occur due to trauma. Consecutive: Consecutive hypermetropia occur due to surgical over correction of myopia or surgical under correction in cataract surgery. Functional: Functional hypermetropia results from paralysis of accommodation as seen in internal ophthalmoplegia, CN III palsy etc. Absence of lens: Congenital or acquired aphakia cause high degree hypermetropia.Far-sightedness is often present from birth, but children have a very flexible eye lens, which helps to compensate. In rare instances hyperopia can be due to diabetes, and problems with the blood vessels in the retina. Diagnosis
A diagnosis of far-sightedness is made by utilizing either a retinoscope or an automated refractor-objective refraction; or trial lenses in a trial frame or a phoropter to obtain a subjective examination. Ancillary tests for abnormal structures and physiology can be made via a slit lamp test, which examines the cornea, conjunctiva, anterior chamber, and iris.In severe cases of hyperopia from birth, the brain has difficulty in merging the images that each individual eye sees.