Advances in Ophthalmology
January is glaucoma awareness month; over 2.7 million Americans, and over 60 million people worldwide, have glaucoma (vision affected by glaucoma pictured). Experts estimate that half of them don’t know they have it. Combined with our aging population, we can see an epidemic of blindness looming if we don’t raise awareness about the importance of regular eye examinations to preserve vision. The World Health Organization estimates that 4.5 million people worldwide are blind due to glaucoma.
Glaucoma is called “the sneak thief of sight” since there are no symptoms and once vision is lost, it’s permanent. As much as 40% of vision can be lost without a person noticing. Glaucoma is the leading cause of preventable blindness. Moreover, among African American and Latino populations, glaucoma is more prevalent. Glaucoma is 6 to 8 times more common in African Americans than Caucasians.
Glaucoma occurs when the normal fluid pressure inside the eyes slowly rises. However, recent findings now show that glaucoma can occur with normal eye pressure. With early treatment, you can often protect your eyes against serious vision loss.
There are two major categories “open angle” and “closed angle” glaucoma. Open angle, is a chronic condition that progresses slowly over a long period of time without the person noticing vision loss until the disease is very advanced, that is why it is called “the sneak thief of sight.” Angle closure can appear suddenly and is painful. Visual loss can progress quickly; however, the pain and discomfort lead patients to seek medical attention before permanent damage occurs.
McGowan Institute for Regenerative Medicine faculty member Joel Schuman, MD, Eye and Ear Foundation Professor and chairman of Ophthalmology, director of the UPMC Eye Center, and interim director of The Fox Center for Vision Restoration, recently lead and published the results of a study entitled “Detection of glaucoma progression by population and individual derived variability criteria.” The abstract from The British Journal of Ophthalmology reads:
PURPOSE: Ocular imaging devices provide quantitative structural information that might improve glaucoma progression detection. This study examined scanning laser polarimetry (SLP) population-derived versus individual-derived cut-off criteria for detecting progression.
METHODS: Forty-eight healthy, glaucoma suspect and glaucoma subjects, providing 76 eyes were used. All subjects had reliable visual field (VF) and SLP scans acquired at the same visits from ≥4 visits. VF progression was defined by guided progression analysis (GPA) and by the VF index. SLP measurements were analysed by fast mode (FM) GPA, compared with the population rate of progression, and extended mode (EM) GPA, compared with the individual variability. The agreement between progression detection methods was measured.
RESULTS: Poor agreement was observed between progression defined by VF and FM and EM. The difference in temporal-superior-nasal-inferior-temporal (TSNIT) average rate of change between VF defined progressors and non-progressors for both FM (p=0.010) and EM (p=0.015) was statistically significant.
CONCLUSIONS: There is poor agreement between VF and SLP progression regardless of the use of population derived or individual variability criteria. The best SLP progression detection method could not be ascertained, therefore, acquiring three SLP scans per visit is recommended.
The Fox Center for Vision Restoration (a partnership between the UPMC Eye Center and the McGowan Institute for Regenerative Medicine) specializes in the five most common and important disease areas associated with vision loss:
- macular disease (retinal degenerations including macular degeneration, retinal vein, and
- diabetic retinopathy
- optic nerve disorders
- corneal scarring
- ocular trauma
- sensory substitution
Additional recent publications from the scientists of the Fox Center include:
High Dynamic Range (HDR) Imaging Concept Based Signal Enhancement Method Reduced the Optical Coherence Tomography (OCT) Measurement Variability. Ishikawa H, Chen CL, Wollstein G, Grimm JL, Ling Y, Bilonick RA, Sigal IA, Kagemann L, Schuman JS.
Klf4 regulates the expression of slurp1, which functions as an immunomodulatory Peptide in the mouse cornea. Swamynathan S, Buela KA, Kinchington P, Lathrop KL, Misawa H, Hendricks RL, Swamynathan SK.
Comparison of Proliferative Capacity of Genetically-Engineered Pig and Human Corneal Endothelial Cells. Fujita M, Mehra R, Lee SE, Roh DS, Long C, Funderburgh JL, Ayares DL, Cooper DK, Hara H.
Illustration: Vision affected by glaucoma. –National Eye Institute.
Louis J. Fox Center for Vision Restoration: Glaucoma—What You Should Know