The need for toric intra‐ocular lens implantation in public ophthalmology departments

Astigmatism is often present in patients undergoing cataract surgery. Implanting toric intra-ocular lenses (IOL) is a safe way to increase the chance of spectacle independence after cataract surgery (Holland et al. 2010); however, toric IOL′s cost more than conventional IOL′s, and in many public ophthalmology departments, toric IOL′s are simply not offered to patients, unless the preoperative corneal astigmatism (PCA) is very high. We experience an increasing patient demand for surgical astigmatism correction in the setting of an upcoming cataract surgery, in particular among younger patients. In this letter, we set out to estimate the need for toric IOL implantation in public ophthalmology departments by analysing the preoperative keratometry values in a large population of cataract operated patients. We conducted a retrospective, cross-sectional survey of the electronic surgical charts from the Department of Ophthalmology at Glostrup University Hospital between 1 January 2002 and 31 December 2013 (12 years). All consecutive, non-paediatric cataract operated patients were included. PCA in dioptre (D) was measured by the IOLMaster (Carl Zeiss Meditec AG, Jena, Germany), Retinomax (Nikon Corp., Tokyo, Japan) or Lenstar device (Haag-Streit AG, Koeniz, Switzerland). Under current Danish law, register studies of this nature do not require approval from The Danish National Committee on Biomedical Research Ethics. In the surveyed period, 14 071 patients (21 524 eyes) were cataract operated, 5558 (39%) men and 8513 (61%) women. Mean age at time of surgery was 72 years (standard deviation (SD) = 12 years). Preoperative, mean power of the flat meridian was 43.19 D (SD = 1.67 D) and mean power of the steep meridian was 44.25 D (SD = 1.72 D). Mean PCA was 1.06 D (SD = 0.90 D). The distribution of PCA in different age groups is seen in Table 1. In 721 (3%) eyes, PCA was 3.00 D or more due to corneal dystrophy/scar(s) (13%), previous vitreoretinal surgery (11%), previous corneal transplantation/keratoconus (5%) or other known causes (7%). The cause was unknown/idiopathic in the remaining eyes (64%). The beneficial effect of toric IOL implantation has been documented for eyes with PCA of 1.50 D or more (Visser et al. 2013). In the present study, 20% of all cataract operated eyes had PCA of 1.50 D or more. For comparison, 16% had a PCA of 1.50 D or more in a large study from a German private eye surgery centre (Hoffmann & Hütz 2010). As seen in Table 1, changing the level of PCA where toric IOL implantation should be considered has a major impact on the number of potential candidates. It is important to remember, though, that all eyes would require cataract surgery with IOL implantation anyway. The number of candidates is also moderated by the contraindications for toric IOL implantation, for example large amounts of irregular astigmatism, presumed capsular instability or eyes that might need keratoplasty in the future. In addition, the proportion of eyes with a high degree of PCA was higher in the 80 years or more age group, which most likely is a result of the increasing corneal astigmatism with age (Gudmundsdottir et al. 2005). It is possible that older patients find spectacle freedom for distance vision less important than younger patients and therefore are less interested in toric IOL implantation. Our results show that there is a large need for toric IOL implantation in public ophthalmology departments. In effect, many patients with cataract could enjoy the benefit of spectacle freedom for distance vision after surgery. Whether the healthcare system in a particular region or country is willing to reimburse toric IOL lenses is another question.