Macular Thickness Variations with Axial Length in Healthy Individuals: Review Article

Background: In the diagnosis and evaluation of many visual illnesses, such as macular edema, macular thickness is an important metric. Gender, age, ethnicity, refraction, and axial length all have an effect on the retinal macular thickness. Preoperative calculations of intraocular lens power during cataract surgery and myopia research necessitate precise and accurate measurements of axial eye length. Objective: To assess the macular thickness in eyes with no ocular pathology, which is important because it serves as a reference for the consequent diagnosis, and to assess the effectiveness of treatment for various macula-related illnesses. Conclusion: Thickness of macula is not the same in all eyes, as it expected to vary with change of eye axial length, which can guide and help in various ocular diseases. INTRODUCTION Ophthalmic illnesses that affect the retina, such as macular degeneration, can be accurately diagnosed and treated by measuring the thickness of the retinal pigment epithelium (RPE). Thus, understanding the typical thickness and distribution is critical in diagnosing macular thickening in various ocular illnesses . Noninvasive optical coherence tomography (OCT) allows doctors to quantify and consistently track the progression of macular thickness. There is a wide range of thicknesses in the macular region determined by OCT, with values ranging from 190 to 387 micrometers. The retinal thickness decreases with age in both the macular and other retinal areas, according to research . The aim of the present review was to assess the macular thickness in eyes with no ocular pathology, which is is important because it serves as a reference for the consequent diagnosis, and to assess the effectiveness of treatment for various macula-related illnesses. Macula: Human eyes have an oval-shaped pigmented area known as the macula lutea, in the center of the retina. It is estimated that the diameter of the macula in humans is around 5.5 mm, and it is split into the foveola, foveal avascular zone, fovea, parafovea, and perifovea regions (Figure 1). When compared to the clinical macula, the anatomical macula is substantially larger. Because the macula is crucial for central high-resolution and color vision, if the macula is diseased, such as in macular degeneration, the vision is much affected . By the ophthalmoscopy or retinal imaging, the clinical macula can be viewed through the pupil. Its name macula lutea derived from the Latin macula meaning "spot," and lutea meaning "yellow" . Due to presences of xanthophyll pigments, lutein and zeaxanthin, the macula appears darker and yellowish in color (3, . They can be found all over the retina, but the macula has the highest concentration . These pigments are scanty in the newborn, but they build up during time through dietary sources. These pigments have a role of reducing chromatic aberration, as they absorb short wavelength visible light, they may also have an antioxidant action, and protect against UVR . https://ejhm.journals.ekb.eg/ 4043 Figure (1): Retinal photo with overlay diagrams demonstrating where and how big macula, fovea, and optic disc are in the eye (1)