Standardization of choroidal thickness measurements using enhanced depth imaging optical coherence tomography

AIM: To describe and evaluate a standardized protocol for measuring the choroidal thickness(Ch T) using enhanced depth imaging optical coherence tomography(EDI OCT).METHODS: Single 9 mm EDI OCT line scans across the fovea were used for this study. The protocol used in this study classified the EDI OCT images into four groups based on the appearance of the choroidal-scleral interface and suprachoroidal space. Two evaluation iterations of experiments were performed: first, the protocol was validated in a pilot study of 12 healthy eyes. Afterwards, the applicability of the protocol was tested in 82 eyes of patients with diabetes. Inter-observer and intra-observer agreements on image classifications were performed using Cohen’s kappa coefficient(κ). Intraclass correlation coefficient(ICC) and Bland-Altman’s methodology were used for the measurement of the Ch T.RESULTS: There was a moderate(κ=0.42) and perfect(κ =1) inter- and intra-observer agreements on image classifications from healthy eyes images and substantial(κ =0.66) and almost perfect(κ =0.86) agreements from diabetic eyes images. The proposed protocol showed excellent inter- and intra-observer agreements for the Ch T measurements on both, healthy eyes and diabetic eyes(ICC 】0.90 in all image categories). The Bland-Altman plot showed a relatively large Ch T measurement agreement in the scans that contained less visible choroidal outer boundary. CONCLUSION: A protocol to standardize Ch T measurements in EDI OCT images has been developed;the results obtained using this protocol show that the technique is accurate and reliable for routine clinical practice and research.

维替泊芬光动力疗法对血管样条纹相关的脉络膜新生血管的治疗

Background: Choroidal neovascularisations (CNV) is themajor cause of significant visual loss in patients with angioid streaks. We evaluated the functional and morphological outcome of Verteporfin photodynamic therapy (PDT) in the treatment of these patients. Methods: This was a retrospective study in two tertiary referral centres over a 3-year period. Examinations included visual acuity assessment with ETDRS charts, binocular fundoscopy and fluorescein angiography. PDT was performed with standard parameters; earlier retreatments were feasible in activeCNV. Results: Fifteen eyes from 12 patients (9 male, 3 female) with a follow-up of 12-50 months (mean 26.1, median 19 months) were included. Five lesions were extraor juxtafoveal and ten were subfoveal. Baseline visual acuity was between 20/63 and 20/16 (mean 20/32, median 20/32). Eyes were treated with two to eight treatments of PDT (mean 4.2, median 4). Treatment intervals were between 5.6 and 72 weeks (mean 12.1, median 9.2 weeks). At the 1-year followup, visual acuity was below 20/200 in 27%(4/15), 20/200 or better in 73%(11/15) and 20/63 or better in 47%(7/15) with an improvement of >3 lines in 13%(2/15), no change in 27%(4/15) and a decrease of >3 lines in 60%(9/15). At the final follow-up examination, all lesions were located subfoveally. Visual acuity was below 20/200 in 47%(7/15), 20/200 or better in 53%(8/15) and 20/63 or better in 13%(2/15) with a change in visual acuity between +2 and-18 lines (mean-9 lines,median -8 lines). No change was noted in 7%(1/15) and a decrease of >3 lines in 93%(14/15) of eyes. The maximum measured greatest linear dimension of the lesion during the follow-up varied between 2400 μm and 6200 μm (mean 3680 μm, median 3600 μm) with an increase in the lesion size compared with baseline values between ±0 μm and +3700 μm (mean+1420 μm, median+1500 μm). Conclusion: PDT for CNV associated with angioid streaks seemed to slow down but not prevent the progression of the disease and associated visual loss. Further modifications of the treatments parameters or a combination with other therapeutical options seem warranted for a more effective treatment of these lesions.