Discontinuation of Silsoft contact lenses
One of the contact lens options we use for the contact lens management of infantile aphakia is the Silsoft lens from Bausch & Lomb. Presently the Silsoft lens is the only silicone elastomer lens on the market and this lens has previously been approved by the Food and Drug Administration in the US for both daily wear and 30-day extended wear for aphakia. The main feature of the silicone elastomer material is its very high oxygen permeability. Due to their increased modulus Silsoft lenses are easier to insert than soft lenses and their rigidity means that they will usually give better visual acuity than soft lenses. Silsoft lenses are more stable on the eye and not as easily rubbed out or mislocated as rigid lenses.
Due to the hydrophobic nature of the silicone lens material, Silsoft lenses incorporate a hydrophilic surface coating. This coating can become scratched or damaged which leads to the lens having a very uncomfortable hydrophobic surface. Alternatively, the coating can become heavily deposited with lipid or mucus – especially if the lenses are worn on an extended wear basis – resulting in a degradation of vision and the need for frequent lens replacement. The lenses are also very expensive, which is a significant factor given that they must be replaced frequently – probably about every three months – due to a combination of lens spoliation and required changes in the lens parameters as the eye grows. Accessing these lenses – given that they come from the US – has also been difficult in the past, although over the last few years this has been a much easier process due to the wonderful support from Bausch & Lomb.
For these reasons, we have tended to use the soft and rigid lenses more for our paediatric patients with aphakia. However, there have been a small number of patients where the Silsoft lenses have provided the best form of contact lens management, especially when these patients are a little bit older – namely between two and four – and hence more active. In the US, the Silsoft lenses are very much the preferred option for the contact lens management of patients with infantile aphakia, with over 50% of these patients being prescribed the Silsoft lenses.
Unfortunately, last week we were informed by Bausch & Lomb that, due to a combination of supplier changes, obsolescence of a critical component and regulatory requirements, they have been compelled to discontinue the Silsoft lenses both in Australia and overseas. While Bausch & Lomb deeply regret having to discontinue these lenses, they are continuing to pursue options that will allow practitioners to provide these lenses – or a similar product – to aphakic patients (both paediatric and adult) in the future. At the present time, we do have access to a small number of Silsoft lenses in stock and so we will be continuing to fit and prescribe these lenses over the next couple of years.