Glaucoma is believed to affect peripapillary retinal nerve fibre layer (pRNFL) thickness, measurement of which has revolutionized the diagnosis of glaucoma in recent years.
The changes in pRNFL thickness are believed to precede the functional damage, however, this thickness is influenced by many factors other than raised intraocular pressure12.
Lee et al in their study on 200 subjects revealed that average ACD 3.35 mm +- 0.4 mm and average pRNFL thickness was 102um +- 11um.
To examine for intraindividual variation in pRNFL thickness, binocular measurements were paired.
Multivariable linear regression models were developed to predict the five measurements of pRNFL thickness (Figure 1).
Paired measurements of pRNFL thickness did not statistically significantly differ in any area (temporal, P = 1; superior, P = 0.2; nasal, P = 0.6; inferior; P = 0.2; global, P = 0.2).
The mean global pRNFL thickness in the study population was 99 [+ or -] 11 [micro]m.
Refractive error met the entry criterion of the model for inferior pRNFL thickness but did not statistically significantly add to the prediction.
We developed regression models to predict the normative values of pRNFL thickness in a Middle-Eastern population.
Ethnic variation in pRNFL thickness has been demonstrated in several studies [11, 12].
Interestingly, a history of diabetes mellitus type 2 generally predicted a considerable increase in pRNFL thickness.