Optics/Refraction/ Contact Lens Free Papers - aioseducation

Optics/Refraction/Contact Lens Free Papers
preventing the contact of scleral lens to the cornea. This is important as these
lenses are indicated for patients with keratoconus and constant rubbing of the
contact lens or cornea may result in scarring. Scleral contact lenses are used
for irregular astigmatism as in keratoconus, pellucid marginal degeneration
and post graft high irregular astigmatism or for ocular surface disease such
as SJS, GvHD. Keratoconus is usually bilateral and is progressive disease. As
keratoconus progresses, the vault may reduce resulting in scarring. Hence,
measuring the vault in the initial fitting may help us in increasing the vault in
cases which would progress such as keratoconus and the same may be can be
applied to post LASIK or sometimes post graft ectasia.
This is important as the same lens can be worn for a longer duration of days if
the other parameters of the fitting remain same. As these lenses rest on sclera
and do not touch the cornea, the fitting is not affected by corneal curvature
and even when the corneal curvature increases, with adequate vault the
fitting may remain the same provided the haptic bearing scleral does not have
any changes. With the reduction in vault there was a theoretical possibility
of haptic compressing the globe but there was no statistically significant
difference between the angles before and after lens wear. So, assessment of
vault with OCT may help in titrating the vault in patients of keratoconus and
ocular surface disease. Gemoules et al have reported OCT being used in the
fitting of the scleral lenses routinely by noting the toricity of peripheral sclera.
12 In our analysis, the vault reduced after four hours of lens wear, which
helped us in ordering the lenses with more vault. This is especially important
in finalizing the fitting of these lenses especially when the vault is borderline.
To conclude, OCT is helpful in determining the vault and angle compression
in fitting patients with fluid ventilated scleral lens and, though our number is
less, the results were promising.
REFERENCES
1. Rathi VM, Mandathara P, Dumpathi S, Vaddavalli PV, Sangwan VS. Boston ocular
surface prosthesis: an Indian Experience. Indian Journal Ophthalmol. In Press
2 Ridley F. Scleral Contact Lenses. Their Clinical Significance. Arch Ophthalmol
1963;70:740-5.
3. Ridley F. Therapeutic uses of scleral contact lenses. Int Ophthalmol Clin 1962;2:687-
716.
4. Pullum KW, Whiting MA, Buckley RJ. Scleral contact lenses: the expanding role.
Cornea 2005;24:269-77.
5. Romero-Rangel T,Stavrou P, Cotter J et al. Gas-permeable scleral contact lens
therapy in ocular surface disease. Am J Ophthalmol 2000;130:25-32.
6. Rosenthal P, Cotter J. The Boston Scleral Lens in the management of severe ocular
surface disease. Ophthalmol Clin North Am 2003;16:89-93.
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