Author(s): Javier Ruiz-Alcocer [[dagger]] 1 2 , David Madrid-Costa 2 , Caridad Pérez-Vives 2 , Santiago García-Lázaro 2 , Jorge Jorge 3
developing countries; intraocular pressure; Mozambique; rebound tonometry
There is a large list of methods for measuring intraocular pressure (IOP), but the Goldmann Applanation Tonometer (GAT) remains the 'gold standard'â for clinical application since it was introduced more than 50 years ago  . Several methods and devices for measuring IOP have been developed to overcome the limitations of GAT, namely its relative invasive character and need for anesthetic and training. The great majority of devices that have been introduced in clinical practice have been compared against GAT in order to study their reliability and repeatability  .
Rebound tonometry (RT) is being increasingly used. Some studies have compared the rebound tonometer Icare® (Tiolat Oy, Helsinki, Finland) with GAT, providing good repeatability and reliability [3-5] . At the same time, other tonometers that employ the RT, such the IOPen, have been analyzed and compared with the Icare, with the Icare being the tonometer that presented the higher accuracy for the measurement of IOP  . Thus, Icare can be considered as one of the most reliable and accurate methods for RT. Icare is a portable tonometer that allows rapid measurement of IOP without the need for topical anesthetic. A small disposable rod probe impacts the cornea and bounces back, the instrument detects this movement and gives the IOP value. Owing to the small size of the probes, Icare allows measurements in different areas of the cornea  . The relatively low cost and the easy and rapid measuring process with Icare makes this instrument a useful tool for optometric examinations in countries with poor medical assistance and where specialized personnel are very scarce. At the same time, disposability of the probes is a determinant advantage of this technique in a country that has a high risk of transmission of infectious diseases, as Mozambique does with a high prevalence of HIV  .
The aim of this study was to report IOP values in a Mozambican, urban, university population and its relation with gender and refractive error. To the best of our knowledge this is the first study providing data about IOP values in Mozambique. We also aim to demonstrate the usefulness of RT and its advantages in measuring IOP in these populations.
The current study was carried out at the beginning of the 2008/2009 academic year, with a sample of 422 subjects (197 men and 225 women) between the ages of 17 and 26 years (23.00 ± 2.18 years). According to the estimations of Krejcie and Morgan  , the sample represents the whole population of young-adult students of superior education that live in urban areas in Mozambique considering a population of 40,000 students in the surveyed age range. All the participants were recruited randomly.
Exclusion criteria from the study included previous or present eye disease, injury with repercussions in visual acuity or corneal physiology, and history of corneal surgery. Medical history, uncorrected visual acuity, fundus examination and external...