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Background and Objective: It is well accepted that accommodation system is characterized by steady state error in focus. Usually near addition lenses are prescribed to prepresbyopic individual for treatment of binocular motor problems such as convergence excess and accommodative disorder. The purpose of this study was to evaluate the near addition lenses in accommodative and vergence responses at three viewing distances. Materials and Methods: This semi-experimental study was done on 42 students of 17-25 years old in Zahedan, South-Eastern Iran during 2009. After correction of refractive error, phoria states with APCT and binocular and monocular lag of accommodation by MEM method with and without +2.00 lenses in three difference distances (30, 40, 50 cm) was measured. Data analyzed by ANOVA, t-student and paired t-tests. Results: There was significant difference between average of lag of accommodation and phoria at various distances, with and without lens (P<0.05). Also, there was significant difference between mean of lag in 3 fixation distance (P<0.017). There was no significant difference between average of lag of accommodation and phoria at various distances in three group of refractive error. Conclusion: Our results showed that, near addition lens reduce the lag of accommodation. It is proposed, therefore, according to near emmetropization theory addition lenses may be effective in reducing of the myopia progression.

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Background and Objective: Glaucoma is one of the most important cause of blindness wordwide. Exact determination of intra ocular pressure is important for the diagnosis and decision making about glaucoma treatment. Central corneal thickness is considered as effective factor on intra ocular pressure and visual field defect. This study was carried out to determine the relationship between central corneal thickness, intra ocular pressure and visual field in normal tension and primary open angle glaucoma. Materials and Methods: This descriptive study was carried out on 45 eyes with normal tension glaucoma and 45 eyes with primary open angle glaucoma in Al-Zahra ophthalmology hospital in Zahedan, Iran during 2010. Intra ocular pressure and central corneal thickness were measured by Goldman tonometer and pachymeter and visual field exanimated by Humphrey perimeter. Data were analyzed using SPSS-16, paired t-test, ANOVA, Mann–Whitney and Pearson corlateion tests. Results: There was significant correlation between central corneal thickness and intra ocular pressure (r=0.309, P<0.05). A significant difference was detected in intra ocular pressure between two type of glaucoma (P<0.05). Mean value of central corneal thickness in patient with mild visual field defect was higher than severe visual field defect but there was not significant statistical difference between central corneal thickness and visual field defect in subjects with glaucoma. Conclusion: This study indicated that increasing corneal thickness is accompanied with intra occular presure.

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Color vision deficiency (CVD) is a defect of vision with disability to distinguish colors. Color vision deficiency can be divided into the two categories, congenital and acquired. Congenital color vision deficiency divided into anomalous trichromacy, dichromacy and monochromacy. The most common congenital CVD was deuteranomalous that mode of inheritance is X linked recessive occurring mostly in males. Acquired CVD can occur as a direct result of illness or any related medicine. Color perception changes in acquired CVD may be secondary to primary ocular disease, drug side effect, or serious systemic disease such as diabetes. Dystrophy of cone, types of maculopathy, crystalline lens changes associated with aging, diabetes, glaucoma, optic nerve diseases and traumatic brain injuries can cause CVD. For acquired CVD, type of defect may not be easy to classify; nevertheless, predominantly is tritanopia and type and severity of the defect fluctuates during of disease. It has been suggested that human evolution to industrialized civilization has led to an increased prevalence of CVD in most population. An acquired CVD can reflect a deficiency in color information processing at anywhere along the related visual pathway, from the photoreceptors to the cortex. Sometimes, assessment of color vision can be helpful to detect a visual impairment in early stages.