Comparison of the influence of cataract and pupil size on retinal nerve fibre layer thickness measurements with time-domain and spectral-domain optical coherence tomography.

BACKGROUND: To investigate and compare the effect of cataract and pupil size on retinal nerve fibre layer (RNFL) thickness measurements using spectral-domain optical coherence tomography (Cirrus OCT) and time-domain OCT (Stratus OCT). DESIGN: Prospective, hospital-based study. PARTICIPANTS: Twenty-five eyes from 25 normal subjects undergoing cataract surgery. METHODS: Three retinal nerve fibre layer (RNFL) thickness measurements were taken before and after dilation, preoperatively and postoperatively, using Cirrus 200×200 Optic Disc Scan and Stratus Fast RNFL Scan. MAIN OUTCOME MEASURES: Linear regression, intraclass correlation coefficient (ICC) and coefficient of variation analysis. RESULTS: Cataract removal caused significant increase in RNFL measurements in both modalities (Cirrus P<0.02; Stratus P<0.001). There was no significant difference in the increase in measurements between the two machines. Pupil dilation had variable and non-statistically significant effect in both (P>0.05). ICC showed excellent reproducibility with Cirrus OCT after mydriasis, preoperatively (ICC=0.78-0.90) and postoperatively (ICC=0.90-0.97), but poor reproducibility before mydriasis (P<0.75). Stratus OCT achieved excellent reproducibility after cataract removal both before (ICC=0.86-0.96) and after mydriasis (ICC=0.92-0.95), but poor reproducibility before cataract surgery (P<0.75). CONCLUSIONS: Cataracts, not pupil size, cause significant underestimation of RNFL measurements in both Cirrus and Stratus OCT. The extent of influence exerted does not appear different between the two instruments. Reproducibility of each machine appears to be affected differently. Mydriasis is required to achieve excellent reproducibility with Cirrus OCT, and media clarity is required with Stratus OCT.

Endoscopic cyclophotocoagulation for the treatment of glaucoma: an Asian experience.

BACKGROUND: To describe the efficacy and safety of endoscopic cyclophotocoagulation in Asian patients with glaucoma. METHODS: Retrospective case series. Consecutive cases of endoscopic cyclophotocoagulation performed by one surgeon during the study period were included. Patients' records were reviewed for clinical and demographic factors, treatments, intraocular pressure (IOP), visual acuity and any complications. RESULTS: Twenty-nine eyes of 29 patients were treated. Their mean age was 73.6 +/- 9.4 years. The mean follow-up duration was 15.9 +/- 8.9 months. Eleven patients had primary open-angle glaucoma, two normal tension glaucoma, six chronic angle-closure glaucoma, five neovascular glaucoma, four secondary open-angle glaucoma and one secondary angle-closure glaucoma. Twenty patients had endoscopic cyclophotocoagulation combined with cataract surgery. Mean pretreatment IOP was 21.8 +/- 6.6 mmHg. Mean post-treatment IOP at 18 months (n = 17) was 16.2 +/- 4.1 mmHg (P = 0.02) and 17.9 +/- 4.9 mmHg (P = 0.18) at 24 months (n = 10). The mean number of anti-glaucoma medications pretreatment was reduced from 2.0 +/- 1.0 to 0.9 +/- 0.9 at 18 months post-treatment (P = 0.04) and 1.2 +/- 0.8 at 24 months (P = 0.13). The overall success rate based on IOP reduction of 20% or greater at last follow-up was 48.3%. Visual acuity was reduced in five eyes. Complications included one case each of hyphaema, bullous keratopathy, transient pigment dispersion and iris burn. CONCLUSION: Endoscopic cyclophotocoagulation may have a treatment role in Asian patients with glaucoma. The success rate appears poorer than previously reported in Caucasian populations. The treatment effect appeared to wane between 18 and 24 months post-treatment.