Correlation Between Myopic Refractive Error, Corneal Power and Central Corneal Thickness in the Egyptian Population

Abstract

Purpose: To find out the correlation between myopic refractive error, corneal power and central corneal thickness (CCT) in the adult Egyptian population. Methods: A retrospective observational cross-sectional study in which we analyzed the preoperative data of 1401 Egyptian myopic patients (1401 eyes) who underwent keratorefractive procedures between 2016 and 2019 in a private eye surgery center. Results: Mean age of patients was 28.1± 5.79 years (range 18-40). Mean CCT in the Egyptian population sample in our study was 539.23± 32.24. Only the corneal power parameters (flat K, steep K and average K) showed a statistically significant difference (p-value <0.001) between males and females. A statistically significant and weak positive correlation of average K with the absolute value of refractive astigmatism (r = 0.063, p-value = 0.018), and between myopic error with average K (r = 0.136, p-value <0.001) was found. Conclusion: Among the myopic adult Egyptian population, the greater the myopic error measured, the steeper the cornea, with a weak positive correlation between refractive error and corneal power.

Study of Myopia Correction Using Nanoporous Polymer Gas Permeable Contact Lenses

“…The tangential topography highlights the presence of a red ring that represents the decompression zone, and the green to blue zone represents the compression zone. The existence of the red ring shows that the "night lens" had or did not have the desired efficiency [13,14]. The change of refraction correlated with the appearance of the corneal topography determined at one day, one month and annually was determined for all patients.…”

“…The tangential topography highlights the presence of a red ring that represents the decompression zone, and the green to blue zone is the compression zone. The existence of the red ring shows that the "night lens" had the desired efficiency [13,14]. Another used corneal topographer is Zeiss Atlas 9000 which can analyse different parameters such as axial and mean curvature, elevation or irregularity of the cornea, the pupil diameter, the steepest or the flatest meridian and the astigmatism.…”

Corneal Epithelial Mapping Among Healthy Egyptian Eyes of LASIK Age Group Using Spectral Domain Anterior Segment Optical Coherence Tomography

“…CORNEAL refractive properties such as central corneal thickness (CCT), anterior curvature, posterior curvature, total corneal power are useful in all types of refractive surgeries. Moreover, understanding how these surgeries affect the corneal shape and structure is becoming increasingly important [1] .…”

Derajat Miopia Berhubungan dengan Ketebalan Kornea Sentral pada Usia 18-40 Tahun

“…The cornea is a transparent structure in the anterior one-sixth of the eyeball, is avascular and is composed of 5 layers, namely: the corneal epithelium, Bowman's membrane, stroma, Descemet's membrane, and endothelium. [9][10][11] The cornea is a barrier and protects other structures within the ball. Eye in fighting infection as well as with the tear curtain layer contributing to two-thirds of the eye's refractive power.…”

“…Under normal circumstances, the central part of the cornea has an average thickness of 540.4 µm (ranging from 520 µm to 565 µm), while in the peripheral parts, the thickness ranges from 612-670 µm. 7,11,12 Corneal thickness will decrease with age. 10 In myopic eyes, there is an eyeball enlargement associated with the cornea's thinning, in which the myopic eye thins approximately 0.018 mm compared to a normal eye.…”