Contrast sensitivity, ocular blood flow and their potential role in assessing ischaemic retinal disease

Abstract

ABSTRACT.Purpose: To examine the definition, evaluation methodology, association to ocular blood flow and potential clinical value of contrast sensitivity (CS) testing in clinical and research settings, focusing in patients with ischemic retinal disease. Methods: A review of the medical literature focusing on CS and ocular blood flow in ischemic retinal disease. Results: CS may be more sensitive than other methods at detecting subtle defects or improvements in primarily central retinal ganglion cell function early on in a disease process. CS testing attempts to provide spatial detection differences which are not directly assessed with standard visual acuity chart testing. Analyzing all studies that have assessed both CS change and ocular blood flow, it is apparent that both choroidal circulation and retinal circulation may have an important role in influencing CS. Conclusion: The concept that CS is directly influenced by ocular blood flow is supported by reviewing the studies involving both. Although the studies in the literature have not established a direct cause and effect relationship per se, the literature review makes it logical to assume that changes in retinal and choroidal blood flow influence CS. This raises the possibility that a subjective visual characteristic, specifically CS, may be able to be evaluated more objectively by studying blood flow. It appears appropriate to study the relationship between blood flow and CS more extensively to develop improved ways of measuring various aspects of blood flow to the eye and to best quantify early changes in visual function.

A pilot study of an acupuncture protocol to improve visual function in retinitis pigmentosa patients

“…Several groups have documented reduced velocity of ocular blood flow in both early and late stage retinitis pigmentosa compared to normal controls; [28][29][30][31][32] however, no previous longitudinal or experimental studies have adequately explored the relationship between changes in ocular blood flow velocity and either improvements or reductions in visual function in retinitis pigmentosa. The relationship between vascular and visual function in retinal ischaemia has been described previously 33 and it might also play a role in patients with retinitis pigmentosa after acupuncture.…”

What Causes Increased Contrast Sensitivity and Improved Functional Visual Acuity After Upper Eyelid Blepharoplasty?

“…4 Twenty-eight eyelids of 14 patients showed statistically significant mean increases in contrast sensitivity after upper eyelid blepharoplasty, resulting in brighter vision. Dermatochalasis was found to be responsible for the field defects because the results were reversed after redundant skin was taped up or following blepharoplasty.…”

Assessment of contrast sensitivity by Spaeth Richman Contrast Sensitivity Test and Pelli Robson Chart Test in patients with varying severity of glaucoma

“…The mean intraocular pressure (IOP) in controls was 15.02 ± 3.201 (10-24) mm Hg, in disc suspects 13.84 ± 3.133 (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) mm Hg and in glaucoma patients 13.11 ± 3.099 (6-22) mm Hg. The distribution of IOP was not similar across the study groups, χ 2 = 7.020, P = 0.03.…”

“…Richman et al [7] found that contrast sensitivity loss correlated more closely and strongly to glaucomatous damage than binocular visual field loss in patients with glaucoma. Contrast sensitivity testing thus may be more sensitive to subtle changes in visual function when compared to other commonly used tests such as visual field and visual acuity evaluating retinal function and thus may also be able to detect glaucomatous changes even prior to visual field and structural changes [8]. This belief led to the development of Spaeth Richman Contrast Sensitivity Test (SPARCS) for detecting contrast sensitivity for patients with glaucoma.…”