Purpose
It is hypothesized that treatment with longer duration (LD) and lower power during transscleral diode cyclophotocoagulation (CPC) might be more effective in lowering intraocular pressure (IOP) in eyes with darker uveal pigment. This study was designed to compare the outcomes of diode CPC, short duration (SD) versus LD treatment with variable power
Methods
In this retrospective study we collected data from eyes undergoing diode CPC using LD (4000 ms) with variable power not exceeding 1000 mW versus SD using 1500 ms with variable power not exceeding 2000 mW with 1 yesr followup. The outcome measures included IOP at 12 months after the procedure, decrease in number of glaucoma medications and visual acuity (VA) at the final visit. Complications in the postoperative period were recorded
Results
Of the 141 eyes that met the study criteria 71 (50.4%) underwent SD CPC and remaining 70 eyes (49.6%) underwent LD CPC. The baseline intraocular pressure (36 ± 10 LD versus 33 ±10 mm Hg, SD) and demographics in both groups were comparable. The most common glaucoma subtype was secondary glaucoma (n=94; 66.7%) followed by congenital glaucoma (n=23; 16.3%) and was uniformly distributed among the 2 groups.<br /> At one year following CPC there was a significant reduction in intraocular pressure in both groups (16.7 mmHg in SD and 17.4 mmHg in LD; p<0.0001). However, the difference in IOP reduction in the LD and SD groups was not significant (p=0.5). A comparable reduction in postoperative glaucoma medications from 2.5 and 2.9 in SD and LD groups respectively to 1.3 (p=0.83) was noted.<br /> A significant drop in LogMAR visual acuity was noted from baseline in the LD group from 2.03 baseline to 2.3 after one year (p=<0.001) whereas in the SD group from 1.87 to 1.96 (p=0.276); the difference in VA drop between groups was significant (0.19; p = 0.075)<br /> Hyphema (SD n=1 vs. n= 0 LD) and hypotony (SD n=3 vs. LD n=2) rates were comparable. The LD group had more intraocular inflammation in the first month after the procedure (n=18) versus 3 eyes in the SD group
Conclusions
Both long and short duration burns during diode CPC were effective in lowering intraocular pressure at 1 year after the procedure. There was no benefit of further IOP lowering with LD treatment. In addition, LD treatment was associated with a greater drop in VA and more common postoperative inflammation.