One hundred consecutive patients who underwent bilateral pan-retinal photocoagulation (PRP) for proliferative diabetic retinopathy were assessed in accordance with the UK Driver and Vehicle Licensing Agency (DVLA) guidelines. Visual acuity was documented, and visual fields were assessed using the Esterman test. Among the 30% of patients who failed to reach the visual standards required for a driving licence, three groups were identified: those who failed to attain either the required binocular visual acuity (n = 4), or visual fields (n = 9), or both (n = 17). Previous studies reveal a large variation in DVLA field test failure following PRP treatment for proliferative diabetic retinopathy. Our results show a 19% failure rate solely attributable to treatment, which is at the lower end of previously reported studies (20-80%). The reasons for this discrepancy are discussed. We conclude that modern treatment procedures for proliferative diabetic retinopathy may be undertaken with the knowledge that in the majority of cases a patient's driving licence is unlikely to be revoked.

The findings confirm that ocular motility problems are not exclusive to scleral buckling, with the incidence being similar in both groups. Slinging of the extraocular muscles and the accompanying dissection, resulting in the 'fat adherence syndrome', must be considered as contributory factors. The visual deficits which inevitably occur as the result of retinal detachment seem to play a more major role in the disruption of binocularity in these cases.

References

(BrJ Ophthalmol 1994; 78: 933-938)

An iron-containing intraocular foreign body usually leads to ocular siderosis if not removed promptly. We report a case involving an iron-containing intraocular foreign body (IOFB) situated on the retina for over 50 years, which did not lead to the expected ocular siderosis. CASE HISTORYAn 84-year-old man presented with a oneyear history of painless gradual reduction of vision in his right eye. The left eye was amblyopic. He also gave a history of having a long-standing retained ironcontaining intraocular foreign body on the retina in the right eye. This was due to an accident when he was hammering on steel during the building of the Clyde Canal 53 years earlier. At the time, the intraocular foreign body was not removed and his visual acuity was 6/9. He was followed periodically, without any ocular complications. He knew he had a retained intraocular foreign body but did not experience any visual symptoms. He eventually developed a right cataract, which was successfully removed three years previously, resulting in a postoperative acuity of 6/12.At this presentation, his visual acuity was 6/18 in the right eye, improving to 6/12 after refraction and 6/60 in the left. On examination, the intraocular lens was well positioned, without posterior capsular opacification, the vitreous was clear and a 1.5 mm intraocular foreign body was seen embedded within the retina with gliosis, outside the macula region, superotemporal to the disc in his right eye (Figure 1). He also had early dry macular degeneration. There was no evidence of the original injury, as the site of entry was through the sclera, which formed a clinically undetectable self-sealing wound, without lens involvement.In view of his past ocular history, an electroretinogram was performed, revealing bilateral delay of rod and cone Figure 1. The iron-containing intraocular foreign body is situated within the retina, with gliosis outside the macular region and supero-temporal to the disc in the right eye.