Experience with argon laser trabeculoplasty in Nigerians.

AIM: To report the safety and efficacy of Argon Laser Trabeculoplasty (ALT) in reducing intraocular pressure (IOP). SETTINGS AND DESIGN: This was a retrospective study performed on 25 eyes of 25 patients. METHODS AND MATERIALS: Consecutive patients who met the inclusion criteria for ALT were recruited from the ophthalmic clinic of the University College Hospital Ibadan, Nigeria and followed up for a minimum period of six months. Two criteria were used to define successful response. Criterion 1 was defined as IOP reduction of 3mmHg or more without additional intervention while criterion 2 was IOP reduction of 20% or more from the pretreatment IOP. STATISTICAL ANALYSIS: Data was analyzed using SPSS version 16. Frequencies and means were generated to observe patterns of variable distribution among the patients. P value < 0.05 was considered significant. RESULTS: The mean pretreatment IOP was 19.9 ±3.1mmHg, (range of 16 to 26 mmHg). Mean post treatment IOP at 6 months was 14.9 ±2.2 mmHg, (range of 11 to 19 mmHg). Mean IOP reduction at one year was 4.6 mmHg, representing a 22.3% drop. There was a statistically significant greater IOP reduction in eyes (P<0.001) with higher pretreatment IOP. Based on criterion 1 and 2, 84.0% of the patients had successful outcome at six months while at one year, 76.9% were successful based on criterion one. CONCLUSION: To the best of our knowledge, this is the first study to report the efficacy of ALT in Nigerians. ALT is safe and effective in reducing IOP in Nigerians. KEY MESSAGES: ALT is safe and effective in reducing intraocular pressure in this population of Nigerians. FUNDING: The present study did not receive any funds.

Effect of Cyclopentolate on In Vivo Schlemm Canal Microarchitecture in Healthy Subjects.

PURPOSE: To characterize the in vivo effect of cyclopentolate on the microstructure of Schlemm canal (SC) in healthy eyes. METHODS: For healthy subjects, 81 serial horizontal enhanced depth imaging optical coherence tomography B-scans (interval between scans, ∼35 µm) of the nasal corneoscleral limbal area were obtained before and 1 hour after cyclopentolate 1% administration in 1 eye. The structures of aqueous and blood vessels in each scan were used as landmarks to select 50 overlapping scans between the 2 sets of 81 serial scans (before and after cyclopentolate administration). The SC cross-sectional area was measured in each of the 50 selected scans. After 3-dimensional reconstruction, SC volume was determined. RESULTS: Twelve eyes (12 healthy subjects) were imaged successfully before and after cyclopentolate administration. Mean age was 27.8±4.9 years (range, 25 to 38 y). Following cyclopentolate administration, mean intraocular pressure did not change significantly (13.9±1.5 to 14.2±1.5 mm Hg; P=0.19). Mean SC cross-sectional area decreased by 17%, from 3563±706 to 2959±460 µm (P<0.001). Mean SC volume in the overlapping area (approximately 1.7 mm of circumferential length of SC) decreased from 6,164,061±1,220,787 to 5,119,462±794,763 µm (P<0.001). The decrease in the mean SC cross-sectional area after cyclopentolate administration was greater in eyes with larger baseline SC cross-sectional area (P<0.001, R=0.873). CONCLUSIONS: Cyclopentolate causes a reduction in SC dimensions in healthy eyes. Future studies are warranted to determine the exact mechanism(s) of this change.