|Year : 2016 | Volume
| Issue : 2 | Page : 19-23
Pattern of anterior segment eye disorders in diabetic patients attending Aminu Kano Teaching Hospital, Kano, Nigeria
Anas Lawan1, Lawan Abdu2, Victoria Pam3
1 Department of Ophthalmology, Eye Clinic, Murtala Muhammad Specialist Hospital, Kano, Nigeria
2 Department of Ophthalmology, Bayero University, Kano, Nigeria
3 Department of Ophthalmology, Ahmadu Bello University Zaria, Kaduna State, Nigeria
|Date of Web Publication||20-Apr-2017|
Eye Clinic, Murtala Muhammad Specialist Hospital, Kano
Source of Support: None, Conflict of Interest: None
Background: The aim of the study is to determine the pattern, frequency, and types of anterior segment disorders in diabetic patients attending the outpatient specialist Diabetes Clinic of Aminu Kano Teaching Hospital (AKTH), Kano. Patients and Methods: This was a descriptive cross-sectional study of diabetic patients in AKTH over a 1-year period. Sample size was estimated using Fisher's formula, and systematic sampling was done to ensure proper randomization of patients that fulfilled the study criteria. Information obtained included patients' bio-data, height, weight, fasting blood sugar (FBS), type and duration of diabetes, associated comorbidities; visual acuity and anterior segment were examined using slit lamp biomicroscopy. Results: A total of 390 patients were examined during the study. There were 166 (42.6%) males and 224 (57.4%) females (M:F ratio = 1:1.35). Mean age was 54.81 ± 12.21 years. Seventy-four (18.97%) patients had type I disease, while 316 (81.03%) patients had type II disease. The mean presenting FBS was 9.52 mmol/L ± standard deviation 4.22, with a wide range of 3.4–24.8 mmol/L. Four patients were bilaterally blind, while ten were unilaterally blind from cataract and glaucoma. Myopia and myopic astigmatism were the most observed refractive errors though not statistically associated with high FBS (×2 = 1.00 P = 0.3165). Chronic blepharitis was the main lid finding and found to be related to high FBS (×2 = 38.68 P< 0.000001). Ocular surface findings included pterygia (3.85%), pinguecula (2.56%), dry eyes (2.31%), and combination of these. Bilateral rubeosis iridis and iris atrophy were found in 8 (2.1%) and 6 (1.5%) patients, respectively. Lens opacities varied in location and visual significance. Nuclear sclerosis was the most common lens disorder while posterior subcapsular cataract was the second predominant type observed and was associated with disease duration >10 years (×2 = 11.48, P = 0.0007039). Conclusion: Anterior segment eye disorders in diabetic patients could be clinically significant and yet unreported by the patient. These may cause low vision and blindness similar to nondiabetic population. The screening protocol in the study location should include routine eye examination.
Keywords: Diabetic eye disease, diabetes mellitus, pattern
|How to cite this article:|
Lawan A, Abdu L, Pam V. Pattern of anterior segment eye disorders in diabetic patients attending Aminu Kano Teaching Hospital, Kano, Nigeria. Arch Med Surg 2016;1:19-23
|How to cite this URL:|
Lawan A, Abdu L, Pam V. Pattern of anterior segment eye disorders in diabetic patients attending Aminu Kano Teaching Hospital, Kano, Nigeria. Arch Med Surg [serial online] 2016 [cited 2019 Jan 23];1:19-23. Available from: http://www.archms.org/text.asp?2016/1/2/19/204800
| Introduction|| |
Diabetes mellitus (DM) is an important health problem worldwide. In 2000, it affected about 170 million persons worldwide. A projected estimate of 366 million will be affected by 2030 mostly in rapid growth developing countries. In Africa, there has been a progressive increase in the prevalence of diabetes and the burden expected to increase even further. The WHO projected a 170% increase in the number of people with diabetes in developing countries by 2025. Like other developing countries, diabetes has been on the increase in Nigeria. This is due to rapid urban growth rate, dietary changes, reduction in physical activity, and increasing incidence of obesity., The Nigerian National Blindness Survey revealed diabetes prevalence of 3.3% in those 40 years and above, 48% of whom were newly diagnosed during the survey.
The current therapeutic strategies indicate an unmet clinical need for preventive therapy. Tight control of blood pressure and glycemia are primary prevention strategies but are insufficient to eliminate risk in all patients. Inadequate knowledge of diabetes care among healthcare providers is another major constraint. The development of standard diabetes practice guidelines to be used by health workers and patients is a major step in meeting the increasing demand for better diabetes care. Adnexal and other anterior segment changes, such as chronic blepharitis, dry eye syndrome, recurrent hordeola, conjunctivitis, refractive changes, anomalies of accommodation, can result in compromised visual function and reduced patients' quality of life. Although advancements in the treatment of these complications have improved the visual outcome, the most important approach remains the prevention of these ocular complications in diabetic patients. Thorough regular eye examination allows early intervention and appropriate treatment. Emphasis on preventive measures is better and cheaper than cure. Thus, it is important that all cadres of eye care workers pay close attention to other nonretinopathy changes in diabetic patients so that all these can be detected and treated early.
| Patients and Methods|| |
The study is descriptive cross-sectional. Fisher's formula was used to obtain the minimum sample size. A total of 390 patients that met the inclusion criteria and consented were recruited to participate in the study.
Ethical approval was obtained from Health Research Ethical Committee of Aminu Kano Teaching Hospital (AKTH), Kano. The study was conducted between June 2012 and May 2013.
All patients had fasting blood sugar (FBS) measured using glucometer (Accu-Chek Inc.) on arrival at the Diabetes Clinic, AKTH, Kano, and the result was recorded on each patient's examination form.
The bio-data, blood pressure, height, weight, ocular and medical, social history of each of the patient were entered into a protocol designed for the study. Every patient then had their eyes examined at the eye clinic of the same hospital.
The lids, adnexae, and anterior segment examination were done with slit lamp. Fundal examination was by slit lamp biomicroscopy with +90D lens and/or binocular indirect ophthalmoscopy.
Manual refraction was by streak retinoscopy at two-thirds meter working distance in a dim room.
Those with dry eye symptoms had corneal sensitivity test, tear film break-up time (TBUT) estimation, and Schirmer's test.
Intraocular pressure was measured using applanation tonometry. Less cooperative patients had pulse air (noncontact) tonometry. Other investigations included gonioscopy, central visual fields, optical coherence tomography, ocular B-scan, and fundus photography according to need. Data were entered using Microsoft Excel and transferred to Statistical Package for Social Sciences version 16.0 (SPSS 16.0, Germany) for analysis.
| Results|| |
Three hundred and ninety patients were examined. One hundred and sixty-six were males and 224 were females (M:F ratio = 1:1.35). The mean age was 54.81 ± 12.21 years. Age and gender distribution are shown in [Table 1].
Seventy-four (18.97%) patients had type I DM and 316 (81.03%) had type II DM. Disease duration was <10 years in 306 patients (78.5%), while the remaining 84 (21.5%) had the disease for 10 years or more.
Twelve (3.1%) patients smoked cigarette and 8 (2.1%) patients consumed alcohol for variable durations of 2–20 years.
The mean presenting FBS was 9.52 mmol/L ± standard deviation 4.22, with a wide range of 3.4–24.8 mmol/L. The reference value for normal FBS in the hospital laboratory is 5.5–6.8 mmol/L. Twenty out of the 34 pregnant women had abnormally high presenting FBS. No patient had HbA1C result of <3 months duration. Values below 7% in diabetic patients are considered normal. Glycemic control was mainly by daily administration of insulin and oral hypoglycemic agents in type I and II diabetes patients, respectively, in addition to dietary measures. Some of the type II patients were on insulin as at the time of examination to achieve good glycemic control. Other combination treatments are presented in [Figure 1].
Most patients had normal presenting visual acuity (VA) [Table 2].
Only 32 (8.21%) patients used spectacle correction for distance and had their aided VA measured. Four (1.5%) patients were bilaterally blind, while 10 (2.6%) were unilaterally blind from cataract and glaucoma. No patient was blind from diabetic retinopathy.
One hundred and eighty-eight (42.21%) patients were found to be emmetropic. The refractive status of the remaining 202 (51.79%) patients is presented in [Figure 2].
Myopia and myopic astigmatism were the most commonly observed refractive errors though not significantly associated with high FBS (×2 = 1.00 P = 0.3165).
Chronic blepharitis, the main lid finding, was found to be strongly related to high presenting FBS [Table 3]. Odds ratio was 10.07 (95% confidence interval).
Three hundred and forty-two (87.69%) patients had normal ocular surface findings. Other ocular surface findings were pterygia, pinguecula, and dry eyes [Table 4].
Twenty-three patients had dry eye as diagnosed using Schirmer's test [Table 5]. Eight of them had associated pterygia while 6 had associated pinguecula with the dry eye. The cornea was clear in 85.6% patients. Abnormal corneal findings were mostly bilateral, i.e., dystrophies, opacities, microerosions, epithelial edema, and decreased sensitivity. The appearance of both irides was normal in 364 (93.3%) patients. Bilateral rubeosis iridis and iris atrophy were found in 8 (2.1%) patients and 6 (1.5%) patients, respectively. The pupil was briskly reactive (direct and consensual) in 358 (91.8%) patients bilaterally. Fourteen (3.6%) patients had relative afferent pupillary defect with sluggish reaction in the fellow eyes and the remaining 18 (4.6%) patients had sluggish reaction bilaterally.
Lens opacities were of variable anatomical location(s) and visual significance. Of the predominating type of cataracts observed, posterior subcapsular (PSC) was particularly significantly associated with disease duration >10 years (×2 = 11.48, P = 0.0007039). Other lens-related findings included pseudophakia with or without posterior capsular opacity (PCO) and surgical aphakia. Unilateral couching was observed in 2 patients (0.5%).
The vitreous was clear in 354 (90.8%) patients. Asteroid hyalosis was observed in 6 patients (1.5%). No patient had vitreous hemorrhage.
| Discussion|| |
This study showed the pattern of diseases that were otherwise undiagnosed. Hence, the pattern of diseases seen is unlikely to be a misrepresentation. Eye studies that are hospital-based tend to have a preponderance of people with advanced diseases, leading to over-representation. The mean age of the study population was mid-fifties in keeping with the global trend. Type II disease was 4 times more common than type I disease; this may signify the predicted upsurge in the incidence of the disease. The slight female preponderance may be explained by the pregnant patients in the study population who required closer monitoring. A large number of the patients in this study had systemic hypertension, which is known to compound vascular leakages, particularly in the retina and kidneys. Tight glycemic and blood pressure control have been shown to significantly decrease the risk of development as well as progression of retinopathy. Cigarette smoking and alcohol consumption were not common among the study population, yet a few that smoked cigarette were among those with proliferative diabetic retinopathy, suggesting it as an additional risk factor as earlier reported. This may have been better demonstrated if there were sizable numbers of cigarette smokers among the study population.
Diabetic patients are generally more susceptible to infection due to hyperglycemic environment conducive to most microorganisms. In the lids, they have increased risk of developing recurrent blepharitis and hordeola. This may be an early sign of the disease in new patients. A population-based study showed an increased risk of conjunctival bacterial infections among diabetes patients. An increased tendency to acquire infection with hyperglycemia was observed in those with chronic blepharitis. The statistical association between the two was significant. This finding supported report of the population-based study that also investigated for bacterial conjunctivitis in diabetic patients.
The refraction results favored neither the association between hyperglycemia and myopia nor the association between hyperglycemia and hypermetropia as observed in other studies.,, Nonetheless, patients with hyperglycemia had their final refraction after they attained normoglycemia to avoid spectacle intolerance. The low number of spectacle users as compared to those that actually needed it may imply low spectacle usage. This may be due to inadequate awareness and low affordability. An earlier study reported myopic and hypermetropic shifts in hyperglycemia and hypoglycemia, respectively. However, a more recent study reported more hypermetropic shift with hyperglycemic episodes. Hyperglycemia was also reported to increase the refractive power of the cornea. The increased incidence of dry eye among the patients is attributable to interplay of several factors. A study found decreased TBUT in diabetics and was associated with peripheral neuropathy and poor glycemic control. This may be due to reduction in the number of conjunctival goblet cells. Reduced corneal sensitivity may reduce reflex tear secretion and longstanding disease may damage the microvascular supply of the lacrimal gland., Corneal complications such as superficial punctate keratitis, recurrent corneal erosions, and persistent epithelial defects are also contributory to dry eye. Reduced corneal sensitivity predisposes to corneal trauma and greater risk of developing neurotrophic corneal ulcers. All the patients diagnosed with dry eye had tear break-up time of <10 s. More than half of them had either associated pterygia or pinguecula with much lower Schirmer's strip wetting. The presence of an abnormal tear film contributes not only to patient discomfort but also to the generation of ocular surface epithelial defects. This may be associated with peripheral neuropathy, poorly controlled disease, and reduction in the number of goblet cells in the conjunctiva, which facilitates tear spreading and stability., Furthermore, dry eye in patients that had panretinal photocoagulation may suggest damage to long ciliary nerves during the procedure. It is thought that longstanding diabetes may cause damage to the microvascular supply to the lacrimal gland, impairing basal tear film secretion.
Reduced corneal sensitivity is believed to be part of the generalized polyneuropathy. These corneal complications have been linked to tear secretion abnormalities, decreased corneal sensitivity, and poor adhesion between epithelial cells and their basement membrane. Abnormalities in the corneal basement membrane may be implicated in the reduced ability of the corneas to act as a barrier to infection. Such a weakened barrier likely accounts for the fact that diabetic patients are more prone to the development of corneal infections.,
Iris neovascularization was observed in a few patients and at the pupillary margins only. No neovascularization involved the entire iris surface and angle. The cause is believed to be capillary dropout in the retina. The fibrous tissue that accompanies neovascularization may contract, causing ectropion uveae or peripheral anterior synechia, both of which were absent in the study population. The diabetic iris epithelium may become depigmented and more likely to release pigments., A weaker response to mydriatic agents used may be a manifestation of generalized diabetic neuropathy, resulting in reduced functional innervation of the dilator muscle.
Cataracts represent a great visual impairment concern in Nigeria., Cataract in diabetic patients develops earlier and progress more rapidly, often necessitating surgical intervention at an earlier age. A study of DM patients in Nigeria and five other Sub-Saharan countries found 6 times risk of developing cataract when compared to the general population. Duration of disease is the most important risk factor for cataract development, especially in patients with early-onset diabetes. There is an increased prevalence and incidence of PSC. Cataract surgery improves vision and allows clear assessment of the fundus. There may be progression of DR following extracapsular cataract extraction, but this was observed to be less with phacoemulsification., None of the pseudophakes with significant PCO had a recent surgery. These patients had successful neodymium-doped-yttrium aluminum garnet laser capsulotomy on referral. The rarity of couching in the result showed a decline in the ancient trend of couching in Nigeria earlier reported, an indicator of improved eye care services and awareness. An analysis of a cohort of 840 subjects with type II diabetes examined in five centers in Nigeria (Lagos, Enugu, and Ibadan) and Ghana (Accra and Kumasi) found that cataract (44.9%) was a more important cause of visual impairment than was DR (17.9%). The comparison of the observed diseases and glycemic control in the study was based on FBS. Comparing this with long-term glycemic control could not be achieved in the study due to lack of recent glycosylated hemoglobin level results in all the studied patients. The observed associations were not standardized for age, sex, and other confounders. Upon the less tendency to misrepresentation of the study findings, the results cannot be generalized to the population. However, it may be cautiously extrapolated to the diabetic population of the study area. Anterior segment eye disorders in diabetic patients could be clinically significant and yet unreported by the patient. These may cause low vision and blindness like in nondiabetic population. Effective strategies to prevent these complications are available with varying extent of implementation. Developing strategies for diabetes prevention, glycemic control, and early regular eye examination will reduce the impact of diabetes on the eye. Patient education and awareness on need for routine eye check-up may increase the number of diabetic patients having regular examination. Testing for glycosylated hemoglobin should be routine and more affordable to enable long-term monitoring of glycemic control. Cost-effective strategies to reduce refractive errors as a cause of visual impairment in diabetic patients are justified and should be explored. Joint specialist care involving obstetrician, endocrinologist, ophthalmologist, and neonatologist given to diabetic women of reproductive age before, during, and after pregnancy is advocated. A detailed and comprehensive protocol manual for screening diabetic patients not for DR only but other diabetic eye complications in the study location should be produced and distributed to all ophthalmologists in the state. Establishment and dissemination of a clear management and referral protocol are also desirable. Larger population-based study involving both diabetic and nondiabetic subjects may likely show better the burden of nonretinopathy eye disorders in diabetic patients.
| Conclusion|| |
Anterior segment Eye disorders can be significant while remaining undetected amongst DM patients attending routine diabetes clinics. These disorders should also be looked for during full assessment of DM patients.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]