Case report

We have recently looked at a cohort of 1418 new referrals (out of a possible 1481 (95.7%)) seen in the 166 consultant outpatient clinics at Southampton Eye Unit, between 1 December 2000 and 31 January 2001. Diagnoses were obtained from the consultant's letter to the referring doctor following the clinic visit to obtain the spectrum of diagnoses made. When two eyes were similarly affected this was recorded as a single diagnostic event.

Cataract related diagnoses³ were found to be most frequent, accounting for 28.8% (597) of the total. This was followed by retinal disease³ at 23.4% (485).

Within the retinal disease group AMD was the single most frequent diagnosis even though it may not have been the primary reason for referral, accounting for 22.3% (108) of the 485 retinal disease cases recorded. Of the 108 AMD patients identified, 62% (67) were female and 38% (41) male, the majority being above the age of 75 (90.7%). Approximately 78% (84) of the total number of patients had AMD affecting both eyes with unilateral involvement in the remaining 22% (24).

Of the 108, most were not felt to need further investigation, having either established and untreatable disease or mild changes. Only 13% (14) underwent further investigation with fluorescein angiography. Of these, four were thought to be possibly suitable for verteporfin treatment with only one fully meeting the criteria for treatment, having a predominantly classical subfoveal membrane.^1,2

Co-existing ocular diseases such as cataract and glaucoma were treated in 49% (53) of the 108 patients, cataract extraction predominating (70% (37)).

The majority of the 107 patients (77) who did not receive verteporfin therapy did not require or were not suitable for any further assistance for their AMD. The remainder (30) were assessed for low vision aids and/or registered as partially sighted/blind.

Comment

Photodynamic therapy with verteporfin has caused much excitement, as it is heralded as a breakthrough in the treatment of exudative AMD.^4,5 A recent editorial in the BMJ suggested that 20–30% of the 200 000 cases of exudative AMD that present to ophthalmologists each year in the United States would benefit from such photodynamic therapy.⁶ Southampton Eye Unit serves approximately 570 000 people as part of its main catchment area, corresponding to approximately 1% of the UK population, and produced only one person over the 2 month study period suitable for treatment with verteporfin by the strict criteria for its use.^1,2 The period studied was before the awareness of photodynamic therapy was fully developed and represents an unselected group of patients having some degree of AMD. Subsequent studies might show a higher proportion of suitable patients once their referral is with a view for verteporfin treatment. Between August 2000 and April 2001 a total of 24 patients were assessed for verteporfin therapy resulting in seven receiving treatment, in keeping with the 4:1 ratio of those assessed and treated in the 2 month study. While it is difficult to extrapolate from such a small number it would seem that the number likely to benefit from verteporfin treatment may well be smaller than suggested even if the treatment criteria was extended to include occult, myopic, and idiopathic lesions.^7,8

Even with the addition of verteporfin therapy to the ranks of the treatment modalities available, the vast majority of AMD patients are still considered untreatable if the treatment criteria are observed.^1,2 Rehabilitation in the form of low vision aids, registration as partially sighted or blind, and the treatment of co-existing ocular disease remains the mainstay of help that the ophthalmologist can offer.⁹ However, the interest created and accepted value of verteporfin should not be underestimated as it represents a new and non-destructive approach to the problem (in contrast with laser photocoagulation) and the first of a novel treatment option likely to be joined by others in the not too distant future.