According to our results, angle kappa reduces with age, and the inter-gender difference is not significant. Largest angle kappas were seen among individuals with emmetropia. Angle kappas were larger in the hypermetropic population compared to the myopic population.

PurposeTo assess the diagnostic power of the Corneal Visualization Scheimpflug Technology (Corvis ST) provided corneal biomechanical parameters in keratoconic corneas.MethodsThe following biomechanical parameters of 48 keratoconic eyes were compared with the corresponding ones in 50 normal eyes: time of the first applanation and time from start to the second applanation [applanation-1 time (A1T) and applanation-2 time (A2T)], time of the highest corneal displacement [highest concavity time (HCT)], magnitude of the displacement [highest concavity deformation amplitude (HCDA)], the length of the flattened segment in the applanations [first applanation length (A1L) and second applanation length (A2L)], velocity of corneal movement during applanations [applanation-1 velocity (A1V) and applanation-2 velocity (A2V)], distance between bending points of the cornea at the highest concavity [highest concavity peak distance (HCPD)], central concave curvature at the highest concavity [highest concavity radius (HCR)]. To assess the change of parameters by disease severity, the keratoconus group was divided into two subgroups, and their biomechanical parameters were compared with each other and with normal group. The parameters' predictive ability was assessed by receiver operating characteristic (ROC) curves. To control the effect of central corneal thickness (CCT) difference between the two groups, two subgroups with similar CCT were selected, and the analyses were repeated.ResultsOf the 10 parameters compared, the means of the 8 were significantly different between groups (P < 0.05). Means of the parameters did not show significant difference between keratoconus subgroups (P > 0.05). ROC curve analyses showed excellent distinguishing ability for A1T and HCR [area under the curve (AUC) > 0.9], and good distinguishing ability for A2T, A2V, and HCDA (0.9 > AUC > 0.7). A1T reading was able to correctly identify at least 93% of eyes with keratoconus (cut-off point 7.03). In two CCT matched subgroups, A1T showed an excellent distinguishing ability again.ConclusionsThe A1T seems a valuable parameter in the diagnosis of keratoconic eyes. It showed excellent diagnostic ability even when controlled for CCT. None of the parameters were reliable index for keratoconus staging.

ABSTRACT.Purpose: To determine the distribution of ocular biometric components and their correlation with age and sex during the ages of ocular development in a 6-to 18-year-old population in Iran. Method: In this cross-sectional study, which was performed in October 2012, multi-stage stratified cluster sampling was used to sample the study population from Dezful schools, a city in the southwest of Iran. Biometric examinations were done by an experienced optometrist using the LENSTAR/BioGraph (WaveLight AG, Erlangen, Germany). Results: Among 864 selected students, 683 participated in the study (response rate: 79.1%); 377 participants (55.2%) were male, and the mean age of the participants was 12 AE 3.4 years (range: 6-18 years). The mean and 95% confidence interval of axial length (AL) were 23.13 mm (22.93-23.33), anterior chamber depth (ACD) was 3.01 mm (2.96-3.06), lens thickness (LT) was 3.58 mm (3.55-3.61), central corneal thickness (CCT) was 549.33 mic (546.59-552.07), corneal radius (CR) was 7.77 mm (7.74-7.81), corneal diameter (CD) was 12.34 mm (12.31-12.38) and pupil diameter (PD) was 4.97 (4.91-5.03). Mean AL, ACD, CD and CR were significantly higher in boys, and mean LT was significantly higher in girls. AL and ACD increased, while LT decreased significantly with age. Myopia was associated with an increase in AL and ACD, and hyperopia was associated with an increase in LT and a decrease in ACD. Conclusion: This study evaluated the distribution of the biometric components of the eye during the ages of ocular development in an Iranian population. In this age range, the majority of the changes were observed in the AL and LT.

The Shahroud Eye Cohort Study was set up to determine the prevalence and incidence of visual impairment and major eye conditions in the 40-64-year-old population of Shahroud as a Middle Eastern population. The first phase of the study was conducted in 2009-10. Using random cluster sampling, 6311 Shahroud inhabitants were invited for ophthalmologic examinations; of these, 5190 participants completed phase 1 (participation rate of 82.2%). All participants were interviewed to collect data on participants' demographics, occupation status, socioeconomic status, history of smoking, and medical and ophthalmic history, as well as history of medication, and the quality and duration of their insurance. DNA and plasma samples, as well as four dots of whole blood were collected from participants. Extensive optometric and ophthalmologic examinations were performed for each participant, including lensometry of current glasses, testing near and far visual acuity; determining objective and subjective refraction; eye motility; cycloplegic refraction; colour vision test; slit-lamp biomicroscopy and intraocular pressure measurement; direct and indirect fundoscopy; perimetry test; ocular biometry; corneal topography; lens and fundus photography; and the Schirmer's (1008 participants) and tear breakup time tests (1013 participants). The study data are available for collaborative research at Noor Ophthalmology Research Center, Tehran, Iran.

No abstract

In comparison with those studies conducted in Iran and other countries, the prevalence of astigmatism was higher in this study. Astigmatism was higher in men and age had an important role in astigmatism and its axis. The prevalence of against-the-rule and oblique astigmatism increased with age.

There is controversy on the interaction of sport exercise and visual functions. Some aspects of visual skills have been evaluated in volleyball players. Eighty-three normal females were categorized in four groups; non-players (NP), beginner volleyball players, intermediate and advanced players. Facility of accommodation and far saccade for optotypes at three distances were measured. The athletes showed better facility of accommodation and saccadic eye movement (SEM) than the non-playing control group. There was a significant difference (P<0.001) between NP and beginner players with advanced players and intermediate players. There are mutual interrelations between the visual system and sensory-motor coordination of the whole body. In a "programed" activity many motor and sensorial elements interactively influence one another. The visual system, as the most important coordinator, navigates the "programed" activities. The facility of accommodation shows how fast clear vision can be accomplished. The SEM shows how fast visual system can fixate on an object. Improvement of these two parameters indicates that the visual system can change fixation very fast and clearly see a new fixation point promptly. These are the requirement for a good volleyball player; hence, we find better visual performance in advanced players than in others.

Compared with other reports, the add power in different age groups was 0.5 D less, and presbyopia was less prevalent. More than 50% of the over 45-year-old individuals were presbyopic and 17% of the over 60 individuals were free of this condition.