Effects of Bright Light, Tropicamide, Pilocarpine, on Ocular Biometry as Measured by Partial Coherence Interferometry
Purpose
To determine effect of bright light, Phenylephrine, Tropicamide, Pilocarpine, and Tamsulosin on anterior chamber depth, lens thickness, and IOL power
Methods
Multicenter prospective comparative study: The Lenstar LS 900 (Haag-Streit) was used for biometric measurements of anterior chamber depth, lens thickness, and IOL power in 50 volunteer subjects. The measurements were done in dark, in bright light and 30 minutes following administration of the pharmacological drops.
Results
72 eyes of 14 males and 22 females were analyzed. The average pupil diameter in dark, bright light, following tropicamide and pilocarpine was 5.2, 3.5, 7.6 and 2.9 mm respectively. Pilocarpine decreased anterior chamber depth (ACD) (p=6.9E-10) and increased lens thickness (LT) (p=1.2E-8) while tropicamide increased ACD (p=1.5E-23) and decreased LT (p=1.3E-11) statistically significantly. Compared to scotopic condition, the PCIOL and ACIOL powers, calculated by Holladay formula, did not change significantly in bright light, or following administration of pilocarpine and tropicamide. The PCIOL powers changed statistically significantly when the Olsen formula was used. (p=0.02 bright light, p=0.04 tropicamide, p=0.04 pilocarpine).
Conclusion
Anterior chamber depth and lens thickness changed significantly following 1% tropicamide and 2% pilocarpine. Though there was a statistically significant difference in the PCIOL power measured by Olsen formula, this difference was clinically insignificant. The selection of IOL power remains clinically unaffected following administration of pupillary dilating or constricting drops.