Frequency and distribution of corneal astigmatism and keratometry features in adult life: Methodology and findings of the UK Biobank study

Abstract

PurposeTo describe corneal astigmatism in the UK Biobank population and to look for associations with other biometric variables and socio-demographic factors.MethodsThis analysis included a subsample of 107,452 participants of the UK Biobank study who underwent an enhanced ophthalmic examination including autorefractor keratometry (Tomey RC 5000, Tomey Corp., Nagoya, Japan). Participants were recruited from across the United Kingdom between 2006 and 2010, and all were between 40 to 69 years. After quality control and applying relevant exclusions, data on corneal astigmatism on 83,751 participants were included for analysis. Potential associations were tested through univariable regression and significant parameters carried forward for multivariable analysis.ResultsIn univariable analysis, the characteristics significantly associated with higher corneal astigmatism (P<0.001), by order of magnitude were, female gender, white ethnicity, lighter skin colour, use of UV protection, lower alcohol intake, lower corneal-compensated intraocular pressure (ccIOP), older age at completion of education, younger age, higher Townsend deprivation index, lower height and lower systolic blood pressure. After inclusion in the multivariable analysis, gender, skin colour, alcohol intake, age at completion of full-time education, ccIOP, age and Townsend deprivation score remained significant (all P<0.001). Increased corneal astigmatism was also found to be significantly associated with amblyopia or strabismus.ConclusionsThis analysis confirms previous associations with astigmatism such as younger age and female gender, and identified novel risk factors including lighter skin colour, lower alcohol intake, later age having completed full time education later, lower ccIOP and higher Townsend deprivation index. Further research is needed to investigate these novel associations.

Intraocular lens power calculation in the elderly population using the Kane formula in comparison with existing methods

“…22 In addition, in accordance with the impact of mean K found in our regression analysis, an increase in corneal power with increasing age could potentially also affect refractive predictability in this age group. [23][24][25] Although, this increase was not demonstrated in our patients, showing no difference in average K between groups (p=0.191), it is possible that a larger dataset, similar to these studies, is needed to exhibit this change. Interestingly, Kane et al 26 formerly evaluated the Kane formula in a specific population of patients with keratoconus.…”

“…It is therefore crucial to address this group's specific anatomical characteristics. 5,[20][21][22][23][24][25] Therefore, it would be of interest to investigate correlation of AL, keratometry and ACD with the refractive outcome in this population in a larger series of patients and to compare the elderly group to another age group. As age may represent differences in anatomical features of elderly patients, regression equation to adjust significant values may improve the predictability of the formula for this age group.…”

Epidemiology and Burden of Astigmatism: A Systematic Literature Review

“…In the included studies, the following risk factors were reported to contribute to the development of astigmatism in adulthood: age, sex, race, education status, pre-existing refractive errors, and various other factors, such as urban versus rural population, degree of nuclear and cortical cataract, axial length, and presence of internal astigmatism. 31 , 35 , 41 , 43 , 46 , 47 , 50 , 51 , 53 – 55 , 58 , 62 – 64 , 66 , 71 , 79 , 81 – 92 …”

Effects of Induced Astigmatism on Spectral Domain-OCT Angiography Quantitative Metrics

“…In addition, even mild keratoconus can progress in 25% of cases, 41 leading to worsening cylindrical refractive errors over time, thus affecting the validity of OCTA cross-comparisons during longitudinal follow up. Although this effect may be more significant in eyes with corneal astigmatism greater than 3.0 D, there is likely less of an effect in the general population as the average corneal astigmatism is typically around 0.50 to 1.50 D; 42,43 but caution should be noted when following quantitative OCTA metrics longitudinally as the average astigmatism may increase and change with age from WTR to against-the-rule (ATR) astigmatism. 43 Additionally, patients who have undergone surgical procedures such as cataract extraction surgery, pterygium stripping and other refractive procedures may experience a sudden and significant change in their cylindrical refractive errors, which precludes an accurate comparison of OCTA scans acquired pre-versus post-procedure.…”