Estimates of dry eye disease in Saudi Arabia based on a short questionnaire of prevalence, symptoms, and risk factors: The Twaiq Mountain Eye Study I.

PURPOSE: To estimate the prevalence and associated risk factors of dry eye disease (DED) among the citizens of Saudi Arabia. METHODS: A cross-sectional prevalence survey was administered to 4066 healthy adults from the five main regions of Saudi Arabia. Initial estimates of the prevalence and associated risk factors of DED were calculated for the general population and then stratified by demographic characteristics such as age, sex, and location. DED was assessed by a short, validated dry-eye questionnaire. RESULTS: The overall prevalence of DED was 49.5 % (n = 2016), including 33.1 % (n = 1347) of participants who reported a previous DED diagnosis and 16.4 % (n = 669) who reported severe symptoms; 14.7 % reported severe symptoms and a previous DED diagnosis (n = 598). The DED prevalence among men was 49.8 % (n = 1005) compared with 50.2 % (n = 1011) for women. The multivariate model analysis confirmed the increased prevalence of DED in women (OR 1.48; 95 % CI 1.30-1.88), those ≥60 years of age (OR 1.99; 95 % CI 1.60-2.81), those who had undergone refractive surgery (OR 1.79; 95 % CI 1.50-2.59), those having undergone acne treatment (OR 1.51; 95 % CI 1.34-1.97), contact lens wearers (OR 1.77; 95 % CI 1.40-2.48), those having taken antiallergy drugs (OR 2.23; 95 % CI 1.55-2.78) or antidepressants (OR 1.60; 95 % CI 1.14-2.44), and those who reported computer use of >6 h per day (OR 1.66; 95 % CI 1.41-2.52). CONCLUSION: Dry eye is a common disease among the Saudi Arabian population. Prevalence is found to be high and vary significantly across the country. DED could be attributed to dry weather, low annual rainfall, low humidity, widespread use of air conditioners, air pollution, high temperature, and exposure to sunlight.

Quantifying interactions between accommodation and vergence in a binocularly normal population.

Stimulation of the accommodation system results in a response in the vergence system via accommodative vergence cross-link interactions, and stimulation of the vergence system results in an accommodation response via vergence accommodation cross-link interactions. Cross-link interactions are necessary in order to ensure simultaneous responses in the accommodation and vergence systems. The crosslink interactions are represented most comprehensively by the response AC/A (accommodative vergence) and CA/C (vergence accommodation) ratios, although the stimulus AC/A ratio is measured clinically, and the stimulus CA/C ratio is seldom measured in clinical practice. The present study aims to quantify both stimulus and response AC/A and CA/C ratios in a binocularly normal population, and determine the relationship between them. 25 Subjects (mean ± SD age 21.0 ± 1.9 years) were recruited from the university population. A significant linear relationship was found between the stimulus and response ratios, for both AC/A (r² = 0.96, p < 0.001) and CA/C ratios (r² = 0.40, p < 0.05). Good agreement was found between the stimulus and response AC/A ratios (95% CI -0.06 to 0.24 MA/D). Stimulus and response CA/C ratios are linearly related. Stimulus CA/C ratios were higher than response ratios at low values, and lower than response ratios at high values (95% CI -0.46 to 0.42 D/MA). Agreement between stimulus and response CA/C ratios is poorer than that found for AC/A ratios due to increased variability in vergence responses when viewing the Gaussian blurred target. This study has shown that more work is needed to refine the methodology of CA/C ratio measurement.