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PurposeTo assess visual outcomes of Coats disease by classification stage.MethodsA retrospective review was conducted on consecutive patients with Coats disease, classified according to Shields classification and with available Snellen visual acuity before and after treatment.ResultsThere were 160 eyes with Coats disease (stage 1 (n=2) vs stage 2A (n=17) vs stage 2B (n=22) vs stage 3A1 (n=26) vs stage 3A2 (n=40) vs stage 3B (n=42) vs stage 4 (n=9) vs stage 5 (n=2)). By comparison, more advanced stage showed greater frequency of poor presenting visual acuity (ConclusionVisual acuity in eyes with Coats disease parallels staging with more advanced stage demonstrating poorer visual acuity at presentation and final visit.

Aims To examine the effect of rounding of visual acuity data on estimates of surgical performance. Method In this observational study, the distribution of 1-year Snellen visual acuity data from 606 endothelial keratoplasties from the NHSBT UK transplant database was analysed. A curve was fitted to the data and used to estimate the frequencies of partly read Snellen lines. The estimates were used to create a virtual database of grafts with Snellen acuities that included individual letter scores. The virtual database was then sampled to produce datasets for 10 virtual surgeons. Various acuity analysis methods were then applied to simulate possible effects of surgeons rounding their data. Results Rounding of acuity data was found to have a notable effect on estimates of surgeons’ success rates. When a criterion of 6/12 or better was applied, the success rates ranged from 62% to 80% using a conservative method of estimation but ranged from 80% to 94% using a less conservative method. Conclusions Rounding of visual acuity scores is an important potential bias in outcome data and should be avoided. If rounding is required we recommend that it is carried out conservatively, giving credit only for lines read completely.

Arden gratings were used to measure contrast sensitivity in 40 patients with retinitis pigmentosa whose Snellen visual acuity was 6/12 or better. When compared with a group of 30 normal subjects the patients with retinitis pigmentosa had substantially decreased contrast sensitivity, especially at high frequencies. The Arden grating test appeared to be a sensitive test of abnormal central visual function in patients with retinitis pigmentosa.

Two clinical interferometers generated gratings directly on to the retina in young experienced observers and also in patients about to undergo cataract surgery. Eyes in the patients with no media opacities were used as controls. We agreed with the manufacturers' claims that gratings are seen on the retina independent of refractive state and that gratings can still be seen through most cataracts. However, we did not find that preoperative retinal visual acuity was of any value in predicting postoperative Snellen visual acuity. Reasons for this are discussed.