Introduction
The prevalence of diabetes mellitus (DM) is increasing globally in both developed and developing countries.1 The global prevalence of diabetes mellitus in the year 2017 was estimated to be approximately 425 million and it is said to increase to approximately 630 million in 2045.2
Type 2 Diabetes mellitus, which is a disease of impaired metabolism characterized by insulin resistance and relative decrease in insulin secretion. Chronic state of hyperglycemia of diabetes, is associated with damage to blood vessels, eyes, kidneys, nerves and heart. There is a high potential for vision loss in patients with diabetes mellitus, with approximately two-thirds of the population having varying degrees of visual impairement after 30 – 40 years of diabetes, manifesting with a range of ocular diseases involving structures from the lids to retina and to cranial nerves.3, 4, 5 Current treatment modalities are aiming to preserve vision and to prevent blindness by timely diagnosis and treatment of ocular manifestations due to diabetes.6 The aim of this study is to evaluate the diabetes related ocular changes in patients with type 2 diabetes mellitus in a tertiary care hospital.
Materials and Methods
A hospital based Observational study which included 90 patients who attended the OPD of our tertiary care hospital over a period of 9 months from January 2019 to September 2019 and the study was approved from the Institutional Ethical committee. Patients aged 40 to 70 years with type 2 diabetes mellitus, of duration of more than 5 years were included in the study. Patients with associated systemic co-morbidities, previous treatment in the eye or ocular trauma were excluded from the study. A detailed history was obtained along with systemic examination was done. All patients were subjected to routine systemic investigations. Ocular examination and evaluation was done which included best corrected visual acuity, Schirmer’s test, corneal sensitivity, Applanation tonometry, gonioscopy and fundus examination using IDO and the observed findings were recorded.
Results
Among the study population of 90 patients, there were 31 patients (34.4%) in the age group of 40-50 years, 38 patients (42.2%) of age group between 51-60 years and 21 (223.3%) patients aged 61-70 years. (Figure 1) and there were 49 males (54.4%) and 41 females (45.5%). (Figure 2). Distribution of study population based on best corrected visual acuity is depicted in Table 1, among which 16 patients (17.7%) had BCVA < 3/60. Ocular manifestations of patients with type 2 diabetes is shown in Figure 3, of which Diabetic retinopathy is the most common manifestation seen in 43 patients (47.7%) followed by Cataract in 40 patients (44.4%).
Table 1
Distribution of study population based on BCVA
| BCVA | Number of patients (n=90) |
| 6/6-6/18 | 20(22.2%) |
| 6/18-6/60 | 26(28.8%) |
| 6/60-3/60 | 28(31.1%) |
| < 3/60 | 16(17.7%) |
Among the diabetic patients who presented with cranial nerve palsy (16.6%), the pattern of involvement of cranial nerve palsy is as follows (n=15).(Figure 4)
Based on the various corneal findings observed in 13 patients of the study population, 2(15.3%) patients had exposure keratopathy, 7 (53.8%) patients had corneal ulcer, 4(30.7%) patients had superficial punctuate keratitis. Incidence of dry eye among the diabetic patients was 25.5%. Association of various types of glaucoma in the diabetic patients are shown in the Table 2. Diabetic retinopathy was present in 43 patients (47.7%) and it was graded according to ETDRS classification as in Table 3.
Table 2
Type of glaucoma among the diabetic patients
| Type of Glaucoma | Number of patients ( n=15) |
| POAG | 7(46.7%) |
| PACG | 2(13.3%) |
| NVG | 5(33.3%) |
| Lens induced glaucoma | 1(6.66%) |
Discussion
Thus this study help us to know the different spectrum of ocular manifestation of patients with Type 2 diabetes mellitus In our study, majority of them were in the age group 51-60 years (42.2%) as in accordance to many studies.7, 8, 9 and males were more in number than females but a study reported that chronic subclinical inflammation showed stronger association of Type 2 DM with women than men.10 According to our study, majority of the patients (31.1%) with best corrected visual acuity was between 6/60-3/60 and around 17.7% had visual acuity <3/60 which emphasizes that all diabetic patients must be aware of the vision threatening complications of diabetes and hence the need for regular eye examinations.11, 12 It was noted in our study that most common acquired cranial nerve palsy due to diabetes(16.6%) was abducens nerve followed sequentially by oculomotor nerve, facial nerve and trochlear nerve. As reported, diabetes is the underlying cause in 25-30% of the patients aged above 45 years who developed acute extraocular muscle palsy.13 Corneal abnormalties were noted in 14.4% of the patients while a study reported that corneal pathologies were detected upto 73.6% of patients with diabetes due to high accumulation of sorbitol.14 Patients with diabetes are at a risk of developing two major types of glaucoma which is primary open angle glaucoma and neovascular glaucoma15, 16, 17, 18 as in our study among the patients detected with glaucoma(16.6%), the most common was primary open angle glaucoma followed by neovascular glaucoma. About 44.4% of the study group manifested with cataract and numerous studies have documented an association between diabetes and cataract.19, 20, 21, 22 Diabetic retinopathy being the major cause of visual impairment in patients with diabetes,23, 24, 25, 26, 27, 28 about 47.7% of patients have been diagnosed with diabetic retinopathy where majority of them had severe NPDR. Thus this study revealed a wide spectrum of ocular conditions that has been associated with diabetes. Management of diabetes eye diseases is primarily preventive and hence regular eye examinations and appropriate ophthalmology referral remains the key to prevent diabetes related vision loss.
