Bacillus
(Corynebacterium) Xerosis and the Ocular Surface
Juan Murube, MD, PhD
The Ocular Surface 2006;4:6-9©2006 Ethis Communications, Inc. Vol 4: No
1
Cell Markers and the
Side Population Phenotype in Ocular Surface Epithelial Stem Cell Characterization
and Isolation
J. Mario Wolosin, PhD
The Ocular Surface 2006;4:10-23©2006 Ethis Communications, Inc. Vol 4:
No 1
The ocular surface is covered by two rapidly renewing and
embryologically-related linings, the corneal and conjunctival epithelia. The
long-term survival of these tissues is ultimately dependent on their respective
resident stem cells. In the corneal epithelium, the stem cells and their early
precursors are exclusively circumscribed to the narrow vascularized limbal
rim that provides epithelial precursor cells to the critically transparent
central cornea. Limbal damage causes an interruption of this essential cell
supply and allows the invasion of the corneal surface by the conjunctival
epithelium, an event that ultimately leads to corneal scarring. The limited
supply of immunocompatible tissue is a major hindrance to efforts to develop
effective procedures for ocular surface reconstruction. This review describes
some of the current work and strategies being developed to achieve the isolation
of the limbal stem cell and define its genetic, biochemical, and functional
make-up. The study of isolated ocular surface stem cells will foster basic
understanding of the environmental requisites for their survival and proliferation
in a self-replicative mode, leading eventually to advances in therapeutic
approaches.
Silicone Hydrogel Contact
Lenses and the Ocular Surface
Fiona Stapleton, PhD, MCOptom, DCLP FAAO,1,2,3
Serina Stretton, PhD,1,2 Eric Papas, PhD, MCOptom, DCLP,1,2,3
Cheryl Skotnitsky, BSc,OD,1,3 Deborah F. Sweeney, BOptom, PhD,
FAAO1,2,3
The Ocular Surface 2006;4:24-43©2006 Ethis Communications, Inc. Vol 4:
No 1
For 30 years, contact lens research focused on the need
for highly oxygen-permeable (Dk) soft lens materials. High Dk silicone hydrogel
contact lenses, made available in 1999, met this need. The purpose of this
review is to examine how silicone hydrogel lens wear affects the ocular surfaces
and to highlight areas in which further research is needed to improve biocompatibility.
Silicone hydrogel lenses have eliminated lens-induced hypoxia for the majority
of wearers and have a less pronounced effect on corneal homeostasis compared
to other lens types; however, mechanical interaction with ocular tissue and
the effects on tear film structure and physiology are similar to that found
with soft lens wear in general. Although the ocular health benefits of silicone
hydrogel lenses have increased the length of time lenses can be worn overnight,
the risk of infection is similar to that found with other soft lens types,
and overnight wear remains a higher risk factor for infection than daily wear,
regardless of lens material. Future contact lens research will focus on gaining
a better understanding of the way in which contact lenses interact with the
corneal surface, upper eyelid, and the tear film, and the lens-related factors
contributing to infection and inflammatory responses.
Nocturnal Lagophthalmos:
An Overview and Classification
Robert Latkany, MD,1 Barbara Lock,
MD,2 and Mark Speaker, MD, PhD1
The Ocular Surface 2006;4:44-53©2006 Ethis Communications, Inc. Vol 4:
No 1
Nocturnal lagophthalmos is the inability to close the eyelids
during sleep. Lagophthalmos is associated with exposure keratopathy, poor
sleep, and persistent exposure-related symptoms. There are a variety of causes
of lagophthalmos, grouped as proptosis/eye exposure etiologies and palpebral
insufficiency etiologies. Although obvious lagophthalmos is usually detected,
it is sometimes difficult to recognize obscure lagophthalmos, due either to
eyelash obstruction or overhang of the upper lid anterior and inferior to
the most superior portion of the lower lid in a closed position. We present
a novel classification system and illustrations of obvious and obscure lagophthalmos.
A diagnosis can usually be made with a focused history and slit lamp examination.
Treatment is multipronged and may include minor procedures or ocular surgery
to correct the lid malposition; natural, topical or oral agents; and punctal
plugs to manage ocular surface effects. Correct and timely diagnosis allows
greater opportunity for relief of patient suffering and prevention of severe
ocular surface pathology, as well as educated planning for future ocular surgical
procedures.
Pipeline
Gary D. Novack, PhD, Features Editor, Pipeline
The Ocular Surface 2006;4:58-60©2006 Ethis Communications, Inc. Vol 4:
No 1
Personal Profile
Deborah Pavan-Langston
The Ocular Surface 2006;4:54-57©2006 Ethis Communications, Inc. Vol
4: No 1