Yellow-tinted intraocular lenses (IOLs) for
cataract surgery are being marketed for their ability to block deleterious blue
light entering the eye.
Short-wavelength automated perimetry (SWAP)
has the ability to detect functional changes in patients with early glaucoma
and without visually significant cataracts.
Cataracts have been reported to cause a
generalized reduction in sensitivity for standard automated perimetry (SAP) and
SWAP tests in normal subjects, and this generalized reduction is more prominent
on SWAP testing compared with SAP testing.
SWAP testing uses a blue stimulus of 440 nm
on a bright yellow background of 100 candela/m2. (Blue On Yellow= BOY)
Yellow-tinted IOLs contain a yellow
chromophore with the ability to absorb the high-energetic visible blue light
between 380 and 500 nm.
It is hypothesized that blue-light–filtering
IOLs may negatively affect contrast acuity and blue/yellow foveal threshold
when compared with UV-only–filtering IOLs in patients without concomitant eye
diseases. Just like nuclear sclerotic cataracts, mentioned above, these IOLs
may affect the quality of SWAP visual field testing.
The koniocellular pathway which uses the
spectrum for blue-yellow light processing has been reported to be damaged in
early glaucoma and yellow-tinted IOLs can affect SWAP significantly.
A number of
studies have been performed to assess the effect of yellow-tinted IOLs on SWAP
testing. Nilofurshan et al., have reported improved MD and FT on SWAP testing in
mild-to-moderate glaucoma patients who underwent cataract extraction and
implantation of yellow-tinted IOLs. Kara-Júnior et al., compared the effect of
clear and yellow-tinted IOLs on SWAP indices in 46 normal subjects (mean age:
68.5 years old) and did not detect any statistically significant differences
between these two IOLs in postoperative values. Espindola also reported blue-on-yellow
perimetry did not appear to be affected by aspherical or yellow tinted IOLs.
Ueda, as well as, Kim have reported no significant influence of yellow-tinted
IOLs on FDT perimetry.
However, Jang et al., reported a statistically
significant difference in MD and PSD values between yellow-tinted and
non-tinted IOLs on SWAP testing.
In view of these studies, it appears that the
presence of glaucoma is not a contra-indication for implantation of yellow-tinted
IOLs .
REFERENCES:
https://www.scielo.br/j/abo/a/9CGyzBgWSfHtpTLGgknnVpr/https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3039191/
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