Optic disc changes following trabeculectomy: longitudinal and localisationof change

Aims - To determine whether there were any changes in the optic disc at 2 y ears after trabeculectomy. To determine the factors that most influenced ch ange and whether change was localised to any region of the optic disc. Methods - 95 patients undergoing routine trabeculectomy as part of the ongo ing Moorfields/MRC 5-fluorouracil trial were recruited into the study. Eyes were imaged preoperatively (4 (SD 3) weeks) with the Heidelberg retina tom ograph (HRT, Heidelberg Engineering), and at 3 months (SD 2 weeks), 1 year (SD 1 month), and 2 years (SD 1 month) after surgery. Parameters investigat ed for change were rim area, rim volume, and maximum cup depth. The predefi ned segment analysis available on the HRT analysis software was used to det ermine segmental change. Results - The images of 70 patients were analysed. Intraocular pressure red uced from 22.25 (SD 3.76) mm. Hg, at the time of preoperative imaging to 15 .27 (SD 4.96) min Hg at 3 months, 14.38 (SD 3.89) min Hg at 1 year, and 13. 80 (SD 3.54) mm Hg at 2 years after trabeculectomy. An increase in rim area and rim volume was present at all time points after surgery, but was only found to be statistically significant at 2 years after surgery. Maximum dep th of cup reduced by month 3 and month 12, but showed a slight increase at 2 years after surgery, although this was still lower than the preoperative measure. Segmental analysis found a significant change in rim volume in the nasal, inferonasal, superonasal, and superotemporal regions at 2 years aft er surgery. No significant regional localisation for change was found at an y other time point or in any other parameter investigated. Conclusions - Reversal of disc cupping is present at 2 years after trabecul ectomy. The factor most influencing change is reduction of intraocular pres sure. Segmental analysis showed that change in rim volume was greatest in t he nasal, inferonasal, superonasal and superotemporal regions at 2 years.