- Dr Christophe Chassain compares hydrophilic with hydrophobic intraocular lenses (IOLs) to establish which model is superior.
He determines that, although hydrophobic lenses offer excellent outcomes in terms of low complication rates and long-term
retinal protection, blue-blocking square-edged hydrophilic lenses are just as effective in terms of preventing posterior capsule
opacification (PCO) and minimizing phototoxicity.
The design of intraocular lenses (IOLs) has evolved rapidly in recent years. Because of the significant advances that have
been made, there are now numerous varieties of IOL on the market and in development; naturally, questions over which is the
best model endure. In particular, there is discussion of whether hydrophilic or hydrophobic IOLs are the superior lenses.
"Hydrophilic IOLs tend to be easier for the surgeon to implant, and are therefore, particularly in the case of very small
incisions, probably a more suitable surgical option than hydrophobic IOLs," said Christophe Chassain, MD, an anterior segment
surgeon at the Clinique Beau-Soleil, Montpellier, France. "Postoperatively, though, hydrophilic lenses have a worse reputation
for prevention of posterior capsule opacification (PCO), which traditionally has been a prime metric used to determine the
success of IOL implantation."
PCO: investigating hydrophilic IOLs
To investigate the truth of this assumption, Dr Chassain conducted a two-year retrospective study to establish the rate of
posterior capsule YAG procedures following implantation of the SlimFlex IOL (PhysIOL).
The SlimFlex is a 26% hydrophilic monobloc IOL with a 6 mm optic, and a 360° posterior square edge. It has an overall diameter
of 10.5 mm, with four haptics at a 5° angle. The lens can be injected through a 2.4 mm incision. MicroSLIM — the microincision
version of the lens, which can be injected through a 1.8 mm incision — is made from 25% hydrophilic material.
Dr Chassain implanted 344 SlimFlex lenses into 191 female and 153 male subjects with a mean age of 77 years (range: 46–94
years) and a mean dioptric power of +20.5 D (range: 9–28 D). Topical anaesthesia was used and, during the coaxial surgery,
the posterior capsule was cleaned; FlexiRing intracapsular rings (IOLTECH Laboratories) were implanted into 34 eyes. A rhexis
of 5.5 mm was achieved in 66% of cases; the rhexis IN position was 76% with an optic overlap.
Similar PCO rates with both lens types
"Of the 344 subjects implanted with the SlimFlex lens, 3.2% required further treatment with Nd:YAG posterior capsulotomy to
combat PCO. Of these, four YAGs were performed in the 180 eyes with an IN rhexis; six in the 57 eyes with an IN/OUT rhexis;
one in the four eyes with posterior fibrosis, and two in the 34 eyes implanted with a FlexiRing," reported Dr Chassain.
The mean follow-up period was 20.6 months (range: 11–28 months). At this stage, 68.6% of subjects had achieved a clear central
"The incidence of post-implantation YAG at two years is very similar for hydrophilic and hydrophobic IOLs," claimed Dr Chassain
(Table 1).1–7 "The high rate of short term success observed with hydrophilic IOL implantation might also yield encouraging results in later
years," he continued.
Table 1: Hydrophobic IOL YAG rates.