Characteristics of the myopic patient population applying for refractive surgery.

Purpose: Assessment of the characteristics of the myopic patient population applying for refractive surgery in order to determine the potential market for myopic refractive surgery.

Methods: Records of consecutive patients who responded to an advertisement for refractive surgery to correct myopia were evaluated retrospectively with regards to patient demographics and the amount and distribution of the refractive error. Data were compared to that available from population-based statistics for distribution of myopia in the general population. For statistical analysis, one sample Student's t-test and two tailed Student's t-test were utilized.

Results: Two hundred fifty seven patients (140 women and 117 men) responded to an advertisement for refractive surgery during the six month period between January and June 1998. Mean spherical equivalent (SEQ) of the patient population was -4.59+/-2.54 D (min;-0.25 D, max;-15.75 D) right eye (OD) and -4.62+/-2.82 D (min;-0.25 D, max;-15.25 D) left eye (OS). Among the patients who had myopia with an astigmatism of at most 1.00 D (n=165), the distribution of refractive error was statistically significantly different from that obtained from population-based statistics, such that, although most of the myopic population (40%) had an SEQ of -1.00 to -2.25 D, the majority of our patients (54.8%) who applied for myopic refractive surgery had an SEQ of -2.50 to -5.00 D. Another striking difference was that, although patients with an SEQ more than -6.00 D were a minority(2%) in the population study, in our study group, they comprised 16.7% of the patients seeking refractive correction. The difference between the SEQ of the right and left eyes ranged from 0.00 D to 13.0 D (mean, 0.89+/-1.5 D), 47.1 % having a difference of at most +/-0.5 D between the two eyes. The mean cylindrical error in the patient population was 0.69+/-0.93 D (min: 0, max: -4.5) OD and 0.69+/-0.96 D (min: 0, max: -4.5) OS. There were no statistically significant differences between the distribution of SEQ or cylindrical refractive error between males and females.

Conclusion: Although a population-based study reported that most of the myopic population (40%) had an SEQ of -1.00 to -2.25 D, the majority of our patients (54.8%) who applied for myopic refractive surgery had an SEQ of -2.50 to -5.00 D. On the other hand, while patients with an SEQ of -6.00 D and more constituted only about 2% of the general population, they accounted for 16.7% of our study population. Therefore, the refractive characteristics of the patient population applying for myopic refractive surgery may not necessarily parallel that of general population-based statistics. In order to establish a more effective refractive surgery practice, it is feasible to perform local studies and reevaluate the requirements of your practice accordingly.