Jemds.com Original Research Article Evaluation of Macular Function Tests with Diabetic Retinopathy Abhinav Ashok Agrawal1, Niharika Krishna Shetty2 1, 2 Department of Ophthalmology, Sri Siddhartha Medical College Hospital and Research Center, Sri Siddhartha Academy of Higher Education University, Tumakuru, Karnataka, India. ABSTRACT BACKGROUND Diabetic retinopathy (DR) is reported to be the leading cause of vision loss in adults Corresponding Author: aged between 20–74 years. Early detection and prompt evaluation is essential to Dr. Niharika Krishna Shetty, C-1403, Wing 1, Vaishnavi ARS prevent the blindness related to diabetes. Simple and quick out-patient department Gardenia, Subrotho Mukherjee (OPD) tests are essential for early detection of maculopathy in diabetes, which will Road, Jallahalli (West), enhance the treatment and rehabilitation. The purpose of this study was to evaluate Dasarahalli, Bangalore – 560057, the correlation of photo stress test and Amsler’s grid test with diabetic retinopathy Karnataka, India. and maculopathy. We also wanted to study the variation in photo stress test and the E-mail: [email protected] patterns of visual disturbances using Amsler grid in different stages of diabetic retinopathy. DOI: 10.14260/jemds/2021/307 METHODS How to Cite This Article: Agrawal AA, Shetty NK. Evaluation of All patients with type 2 diabetes were included for a study duration of one year. A macular function tests with diabetic cross sectional study design was planned. Anterior and posterior segment evaluation retinopathy. J Evolution Med Dent Sci was done. Photo stress test was performed with a torch light and the recovery time 2021;10(20):1463-1468, DOI: was recorded. Amsler grid was performed on each patient at 33 cm distance. The 10.14260/jemds/2021/307 results were recorded in terms of micropsia, macropsia, metamorphopsia, and any other ill-defined scotomas. The posterior segment, in terms of vitreous and retina was Submission 04-11-2020, evaluated with 20 D lens on an indirect ophthalmoscopy and the macular details were Peer Review 15-03-2021, Acceptance 22-03-2021, evaluated on a 90 D lens with slit lamp biomicroscopy. Early Treatment Diabetic Published 17-05-2021. Retinopathy (ETDR) classification was used for classifying the retinopathy and the maculopathy stage in patients. Copyright © 2021 Abhinav Ashok Agrawal et al. This is an open access article RESULTS distributed under Creative Commons There was a correlation between paroxysmal supraventricular tachycardia (PST) and Attribution License [Attribution 4.0 International (CC BY 4.0)] the stage of diabetic retinopathy; between PST and diabetic maculopathy; with increasing severity of diabetic retinopathy and maculopathy associated with higher or prolonged PST values. No correlation was found between Amsler’s grid and DR staging. CONCLUSIONS PST can be used to assess severity of diabetic retinopathy in a pre-clinical and early clinical stage in places where access to the equipment for posterior segment evaluation is unavailable. Amsler’s grid evaluation did not have a role in evaluation of macula in cases of diabetic retinopathy. KEY WORDS Macula, Amsler, Photostress Test, Metamorphopsia J Evolution Med Dent Sci / eISSN - 2278-4802, pISSN - 2278-4748 / Vol. 10 / Issue 20 / May 17, 2021 Page 1463 Jemds.com Original Research Article BACKGROUND Clinically, the macula is evaluated on 90 diopters lens with slit lamp biomicroscopy and the macular oedema is classified as focal oedema due to cluster of microaneurysms, diffuse Diabetic retinopathy is reported to be the leading cause of macular oedema due to loss of normal foveal contour and 1 vision loss all over the world. As well, it is said to be the cystoids macular oedema due to appearance of cystic spaces leading cause of vision loss in adults aged 20 – 74 years.2 In the on the macular area.7 Clinically significant macular edema is past decade, diabetic retinopathy was noted as the fifth most defined as one or more of the following: retinal thickening at common cause of preventable blindness and fifth most or within 500 μm of the center of the macula; hard exudates at 3 common cause of moderate to severe visual impairment. The or within 500 μm of the center of the macula, if associated with causes of vision loss in diabetes were found to be severe in non adjacent retinal thickening; or a zone or zones of retinal proliferative diabetic retinopathy, proliferative diabetic thickening one disc area in size, at least part of which is within retinopathy and diabetic macular oedema.4 Among these one disc diameter of the center of the macula.8 causes, proliferative diabetic retinopathy caused vision loss Methods of investigating the macular area include clinical more frequently in type 1 diabetes whereas diabetic macular evaluation, fluorecein angiography and ocular coherence oedema was the frequent cause of vision loss in type 2 diabetes tomography. The functional evaluation of macula is done with 5 mellitus. Diabetic maculopathy is also reported to be the various macular function tests such as Maddox rod test, invariably present in cases of proliferative diabetic photostress recovery test, blue-light entoptoscopy, Purkinje 6 retinopathy. entoptic phenomenon and visual-evoked response and Diabetic macular oedema was defined clinically by hard electroretinography (VER - ERG). exudates due to microaneurysms and blot hemorrhages Photostress test was introduced by Bailliart (1954) who within one disc diameter of the foveal center. Clinically dazzled the macula with the light of an ordinary significant macular edema (CSME) is defined by the presence ophthalmoscope and measured recovery time of central of edema within 500 μm of the foveal center. Hence, CSME was vision. The basis of the test is to utilize an induced fatigue of 1 a more severe form of diabetic retinopathy. Many tools have the macula analogous to the induced fatigue utilized for the been used to detect the incidence and prevalence of diabetic examination of the heart. The photostress test is a simple, easy maculopathy. These methods include clinical methods to and quick clinical technique that can differentiate between stereoscopic and non-stereoscopic fundus photographs to retinal (macular) and post-retinal (e.g.optic nerve) disease.9 ocular coherence tomography (OCT). OCT-detected diabetic The Amsler’s grid is a type of macular function test used to macular oedema (DME) was found to have a greater degree of detect the central 10 degrees of visual field, mainly in the area disagreement with the clinical definition of CSME, and not all around fixation. It is a high contrast supra-threshold test.10,11 patients who had macular thickening detected on OCT After correcting for near refractive error, each participant was 1 progressed to have clinical DME. asked to view each Amsler’s grid (10 & 10 cm) at a distance of In contrast to diabetic retinopathy, the epidemiology of 33 cm, ensuring that each box on the Amsler’s grid diabetic macular oedema is less studied. Existing studies are corresponds to 1 degree of visual field (VF). A similar high split between the use of two diagnostic criteria, one for DME quality paper copy of the Amsler’s grid was used for each and the other for CSME.The diagnosis of DME using this same patient. The Amsler’s grid can be called as a type of visual field modality is challenging as macular thickening is difficult to testing.12 Currently, clinical assessment of retinal function loss assess in non-stereoscopic photographs. There is no in diabetic maculopathy relies on visual acuity. Unfortunately, 1 consensus on OCT based severity classification for DME. by the time visual acuity is reduced, the signs of retinal damage Macular edema is often associated with diabetic are already present.13,14,15 Many studies have shown that there retinopathy severity. Diagnosis of DME in subjects is either are other psychophysical16,17,18,19,20 and electrophysiological following the manifestations of macular edema in a previously tests that are based on contrast sensitivity to detect early type 2 diabetes mellitus diagnosed individually, or some may vision loss in diabetics.21,22 However, these tests are time even have decreased vision from macular edema as the consuming and expensive. presenting sign. However, a very small proportion of patients In this study, we have tried to evaluate the macular 7 present like this as for most of the symptoms are masked. function in diabetes using Amsler’s grid and photo stress test, The pathopysiology of diabetic macular oedema is which are simple and fast OPD tests. These tests might help us explained by the retinal circulation. Normal retinal circulation to detect any subclinical functional loss if exists irrespective of is unique: retinal capillaries are non-fenestrated and capillary anatomical changes found in maculopathy. endothelial cells have tight junctions. Normal capillaries do not leak fluid or blood. There is no lymphatic system in the retina so in the presence of retinal pathology, leaking fluid can accumulate and cause edema or swelling of the retinal layers. METHODS This also leads to macular oedema.7 Clinical manifestations of diabetic macular oedema are also varied. All the diabetic patients visiting Department of Ophthalmology Most of the patients whose central macula is spared are at SSMC,Tumkur, from May 2019 to May 2020 were included asymptomatic. Extremely observant patients may notice a in the study. The ethical clearance was obtained from the paracentral scotoma corresponding to focal hard exudates and institutional ethical committee. Letter reference number SSMC oedema in such cases. The central involvement of the macula / IEC - 2 / April - 2019, dated 20 / 4 / 2019. The study design of recent origin may also remain asymptomatic. If the oedema was a cross sectional study design. Detailed ocular evaluation in the central macula persists, these patients may later was done including anterior segment and the posterior complain of mild visual symptoms like gradual loss of vision, segment.