Refractive error may influence mesopic pupil size.
OBJECTIVE
To identify factors which affect mesopic pupil diameter in refractive surgery patients.


METHODS
This retrospective study was performed at the 1st Ophthalmology Clinic in Ankara Ataturk Training and Research Hospital, Ankara, Turkey.


METHODS
Medical records of 412 refractive surgery candidates who applied between 2006 and 2008 were reviewed. Detailed ophthalmological examination data were obtained from medical records. Pupil size measurements were performed with a COAS Ocular Wavefront analyzer in mesopic conditions. Relationship between mesopic pupil diameter and age, sex, spherical refractive error (D), magnitude of astigmatism (D), type of astigmatism, spherical equivalent, and average keratometry were analyzed by means of univariate and multivariate regression analyses.


RESULTS
Mean mesopic pupil diameter was 6.19 +/- 0.88 mm. Mean pupil diameter (mean +/- standard deviation) was 5.70 +/- 1.01 in hypermetropia, 6.04 +/- 0.79 mm in mixed astigmatism, and 6.33 +/- 0.82 mm in myopia. The difference in mean mesopic pupil diameters between myopes and hypermetropes was statistically significant (p = 0.001). However, differences with regard to mean pupil diameters between myopes and mixed astigmatism (p = 0.660) and between hypermetropes and mixed astigmatism (p = 0.109) were not significant. Mean pupil diameter was 6.00 +/- 0.99 mm in against the rule astigmatism, 5.96 +/- 0.84 mm in oblique astigmatism, and 6.27 +/- 0.84 mm in with the rule astigmatism. Mean mesopic pupil diameter in with the rule astigmatism group was higher than oblique astigmatism group. Spherical refractive error (r = -0.213, p = 0.001), cylindrical refractive error (0.197, p = 0.001), and age (r = -0.341, p = 0.001) showed correlation with pupil diameter.


CONCLUSIONS
This study showed that age and magnitude of both spherical and cylindrical refractive error are the most determinative factors on mesopic pupil size.
Ankara Ataturk Training and Research Hospital, 1st Ophthalmology Clinic, Bilkent, Ankara, Turkey.
Hasan Basri
HB
Cakmak
Nurullah
N
Cagil
Huseyin
H
Simavli
Betul
B
Duzen
Saban
S
Simsek
D057128:Aberrometry; D000293:Adolescent; D000328:Adult; D001251:Astigmatism / Q000503:physiopathology; D057108:Corneal Wavefront Aberration / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D055255:Mesopic Vision / Q000502:physiology*; D008875:Middle Aged; D011680:Pupil / Q000502:physiology*; D012030:Refractive Errors / Q000503:physiopathology*; D012189:Retrospective Studies