RETINAL DISEASES IN A TERTIARY HOSPITAL IN SOUTHERN NIGERIA

Abstract

Background

Retinal diseases are an important and common cause of ophthalmic consultation.

Aim

To determine the pattern of retinal diseases in the ophthalmic department of a tertiary hospital in Southern Nigeria.

Patients and Methods

A retrospective review of the case folders of patients with retinal pathologies seen between 2012 and 2013 was performed. Relevant demographic and clinical data was recorded. Analysis was performed for frequencies, proportions and percentages with the GraphPad Instat Software, Inc. version V2.05a program, San Diego, CA.

Results

There were 185 patients made of 94 (50.8%) males and 91 (49.2%) females with a peak age group of 61-70 years, (range 1-85 years) who made consultations for retinal diseases. Age related macular degeneration, 37(15.0%), and macula hole, 10(4.0%), were the common macula pathologies while retinal detachment, 11(4.5%), was the most common condition that required emergency vitreo-retinal surgical intervention. Diabetic retinopathy/maculopathy, 31(12.6%), hypertensive retinopathy 22(8.9%), and retinal vascular occlusion 12(4.8%), were the common retinal vascular diseases found. Bilateral visual impairment (low vision and blindness) from retinal diseases was present in 28(14.4%) persons. The common vitreo-retinal treatment options were use of intravitreal antivascular endothelial growth factors 32(13.0%), laser 16(6.5%), and vitreoretinal surgery in 22(8.9%) eyes.

Conclusion

Retinal diseases remain an important cause of ophthalmic consultation and visual loss. Provision of facilities to manage these conditions will improve service delivery and quality of lives of affected patients.

Introduction

Retinal diseases are the major causes of visual impairment in wealthy countries1. In developing countries, the leading causes of avoidable blindness are cataract, trachoma, onchocerciasis, corneal scarring and glaucoma 2. With various intervention programmes, the emphasis has been on the elimination of these conditions such as availability of low cost technology resulting in increasing cataract surgical rate, SAFE strategy for trachoma representing Surgery, Antibiotics, Facial cleanliness and Environmental change which is promoted through the Alliance for the Global Elimination of Trachoma (GET 2020) to eliminate trachoma as a cause of blindness by the year 20201^-3. Others include effective vector control programmes and mass community-based ivermectin treatment programmes for onchocerciasis and vitamin A distribution and food fortification for corneal scarring from Vitamin A deficiency4,5. All these have resulted in a gradual but definite reduction in the burden of blindness from these conditions. This has also resulted in less attention being paid to retinal diseases leading to late detection with equalling blinding and almost irreversible visual loss from preventable and treatable causes like diabetic retinopathy, retinal detachment and age related macular degeneration (ARMD). There are limited low vision and visual rehabilitation services available for cases with irreversible visual impairment. Furthermore, changes in dietary habits and increasing sedentary lifestyle have led to increased incidence of non-communicable diseases such as diabetes6^-8, this translates to an increasing number of patients with diabetic retinopathy. Many studies have reported on retinal diseases in different parts of Nigeria9^-18. This study was conducted to determine the profile of retinal diseases seen in a tertiary hospital located in Benin City, Southern Nigeria, to proffer recommendations which will aid proper planning for effective service delivery.

Patients and Methods

This was a hospital based retrospective review of cases with vitreo-retinal conditions seen in the eye clinic of the University of Benin Teaching Hospital, Benin City, Southern Nigeria from January 2012 to December 2013. Demographic, clinical data and ophthalmic assessment performed were retrieved. Information obtained and recorded included age, sex, diagnosis, associated ocular and systemic co-morbidities and treatment modalities for the patients. Diagnosis of systemic diseases and medical conditions such as hypertension, diabetes mellitus, retroviral disease, peptic ulcer disease and osteoarthritis were made in patients who were already on treatment by their physicians. Newly diagnosed cases of hypertension was made in patients in which the blood pressure was > 140/90mmHg in at least 2 separate readings19 while diabetes mellitus was diagnosed in patients with fasting plasma glucose of ≥126 mg/dl (7.0 mmol/l)20. Fasting was defined as no caloric intake for at least 8 h. Retinal diseases were diagnosed following clinical bio-microscopic examination with +78D stereoscopic non-contact lens (Volk Optical, Inc. Ohio) and/or binocular indirect ophthalmoscopy (Appassamy AAIO wireless; Appasamy Associates, Chennai, India) with +20D lens (Volk Optical, Inc. Ohio) after pupillary dilatation with guttae tropicamide 1% or phenylephrine 2.5%. Confirmatory investigations were requested consisting of fundus fluorescein angiography and/or optical coherence tomography. Tailored laboratory and radiologic investigations advised to aid or confirm diagnosis include full blood count, fasting plasma glucose, glycosylated hemoglobin, fasting serum lipid profile, haemoglobin electrophoresis, erythrocyte sedimentation rate, retroviral screen, VDRL, urinalysis and renal function tests (serum electrolyte, urea, and creatinine), Mantoux test and chest x-ray, ocular ultrasound and computed tomography scan. Data obtained were analyzed for frequencies, proportions and percentages with GraphPad Instat Software, Inc. version V2.05a program, San Diego, California. Ethical guidelines concerning use of subjects were followed in the research.

Results

A total of 185 patients with vitreo-retinal pathologies were studied made of 94 (50.8%) males and 91 (49.2%) females. The age range was 1 to 85 years with the peak age group between 61-70 years. The demographic profile is presented in Table 1. Some patients had other systemic and ocular co-morbidities. The more common systemic co-morbidities in the patients were hypertension, 36 (19.5%), and diabetes, 33(17.8%) while refractive errors and cataract were the common ocular co-morbidities encountered in 36(19.5%) and 24(13.0%) patients respectively as presented in Table 2.

Table 1. Demographic characteristics of patients.

Age in years	Sex		Total (%)
	Male	Female
≤ 10	5	5	10
11-20	6	5	11
21-30	8	5	13
31-40	10	9	19
41-50	15	17	32
51-60	19	20	39
61-70	25	24	49
71-80	5	5	10
> 80	1	1	2
Total	94	91	185

Table 2. Ocular and Systemic co-morbidities.

*Disease	Number of patients Male Female		Total (%)
Ocular
Refractive errors	19	17	36 (19.5)
Allergic conjunctivitis	9	11	20 (10.8)
Cataract	11	13	24 (13.0)
Glaucoma	10	8	18 (9.7)
Pterygium	7	5	12 (6.5)
Optic atrophy	2	1	3 (1.6)
Strabismus	1	1	2 (1.1)
Systemic
Diabetes mellitus	18	15	33 (17.8)
Hypertension	19	17	36 (19.5)
Osteoarthritis	0	1	1 (0.5)
Asthma	1	1	2 (1.1)
Retroviral disease	3	2	5 (2.7)
Peptic ulcer disease	1	1	2 (1.1)
Sickle cell disease	2	0	2 (1.1)
*Some patients had multiple pathologies

The common retinal vascular diseases were diabetic retinopathy/maculopathy in 31(12.6%), hypertensive retinopathy, 22(8.9%) and retinal vascular occlusion in 12(4.8%) eyes respectively. Age related macular degeneration and macula hole were the common macula pathologies documented in 37(15.0%) and 10(4.0%) eyes respectively while retinal detachment was the most common condition that required emergency vitreo-retinal surgical intervention in 11(4.5%) eyes. These are shown in Table 3. Bilateral visual impairment (low vision and blindness) from retinal diseases was present in 28(14.4%) persons of which 21(10.8%) were blind while uniocular visual impairment was documented in 39(20.0%) persons. The causes of bilateral blindness were age related macular degeneration 8(38.1%), diabetic retinopathy 5(23.8%), chorioretinitis, mostly congenital toxoplasmosis 4(19.0%), retinal detachment 2(9.5%) and retinitis pigmentosa 2(9.5%).

Table 3. Ocular diagnosis among patients with vitreoretinal diseases.

Diagnosis	Number of eyes (%)	Number of patients (Male : Female)
Age-related macular degeneration	37 (15.0)	27 (13:14)
Idiopathic polypoidal choroidal vasculopathy	5 (2.0)	4 (1:3)
Central serous retinopathy	5 (2.0)	3 (2:1)
CMV retinitis	5 (2.0)	3 (2:1)
Diabetic maculopathy/retinopathy	31 (12.6)	20 (9:11)
Hypertensive retinopathy	22 (8.9)	15 (9:6)
Macular hole	10 (4.0)	8 (3:5)
Presumed toxoplasmic retinochoroiditis	10 (4.0)	9 (5:4)
Retinochoroiditis (Not toxoplasmosis)	2 (0.8)	2 (1:1)
Retinal detachment/breaks	11 (4.5)	9 (4:5)
White dot syndromes-Puntate Inner Choroidopathy	2 (0.8)	1 (1:0)
Serpingenous choroiditis	1 (0.4)	1 (0:1)
Retinitis pigmentosa	10 (4.0)	5 (3:2)
Retinoblastoma	6 (2.4)	4 (3:1)
Retinal vein occlusion	10 (4.0)	8 (5:3)
Retinal artery occlusion	2 (0.8)	2 (1:1)
Posterior vitreous detachment	10 (4.0)	7 (3:4)
Sickle cell retinopathy	4 (1.6)	2 (2:0)
Myopic CNVM	1 (0.4)	1 (1:0)
Inflammatory CNVM	1 (0.4)	1 (0:1)
Pseudophakic CMO	5 (2.0)	4 (3:1)
Viral retinitis( Not CMV retinitis)	1 (0.4)	1 (0:1)
Retrobulbar optic neuritis	2 (0.8)	2 (0:2)
Neuroretinitis	1 (0.4)	1 (1:0)
Hereditary dystrophies/ Choroideraemia	1 (0.4)	1 (1:0)
Aphakic CMO	2 (0.8)	2 (1:1)
NAION	1 (0.4)	1 (0:1)
Traumatic optic nerve avulsion	1 (0.4)	1 (1:0)
Uveitic CMO	2 (0.8)	2 (1:1)
Dislocated lens in vitreous	4 (1.6)	4 (3:1)
Peripheral retinal degenerations/lattice	20 (8.1)	16 (7:9)
Tersons syndrome	1 (0.4)	1 (0:1)
Vitreomacular traction and Epiretinal membrane	5 (2.0)	4 (2:2)
Pathologic myopia	6 (2.4)	3 (2:1)
Idiopathic intracranial hypertension	1 (0.4)	1 (0:1)
Vitreous haemorrhageOthers	5 (2.0)4 (1.6)	5 (2:3)4 (2:2)
Total	247	185 (94:91)
Key: CMV= Cytomegalovirus, CNVM= Choroidal neovascular membrane, CMO= Cystoid macular oedema, NAION=Non arteritic inflammatory optic neuropathy

The most common vitreo-retinal management options in eyes with retinal conditions was use of intravitreal pharmacologic agents in 32(13.0%) for cases of neovascular age related macular degeneration, diabetic macular oedema, retinal vein occlusion with macular oedema, idiopathic polypoidal choroidal vasculopathy, myopic choroidal neovascular membrane and inflammatory choroidal neovascular membrane, which was from toxoplasmosis. Intravitreal antivascular endothelial growth factors were the pharmacologic agents used which was mostly bevacizumab and less commonly ranibizumab. Laser was performed in 16(6.5%) eyes which was panretinal laser photocoagulation (PRP) for proliferative diabetic retinopathy and ischaemic central retinal vein occlusion with retinal neovascularization; sector laser photocoagulation for branch retinal vein occlusion with fibrovascular proliferation, focal laser in focal diabetic macula oedema and barrage/delimiting laser photocoagulation in cases of lattice with holes in fellow eye retinal detachment and subclinical retinal detachment. Focal laser was not used in eyes with central serous chorioretinopathy as signs of resolution occurred within 3 months of conservative treatment. Modified grid laser photocoagulation was not performed in eyes with clinically significant macula oedema. Scleral buckling was performed in 3(1.2%) eyes of simple rhegmatogenous retinal detachments with good media clarity. Vitrectomy was the management choice in 19(7.7%) eyes of unresolving vitreous haemorrhage, complicated, long standing retinal detachments, macula holes with good prognosis and dislocated lenses in vitreous. Low vision services were offered to 11(5.6%) patients in cases of bilateral visual impairment which will not benefit from other modes of treatment.

Discussion

Vitreo-retinal diseases are an important cause of ophthalmic consultation in Nigeria9^-18. It is responsible for a significant cause of low vision and blindness21^-24. This study found that the elderly age group formed a higher proportion of patients with vitreo-retinal diseases. With increasing life expectancy, there is need to improve or maintain the quality of life in persons as they age gracefully25. A higher incidence of falls and fractures occurs in poorly sighted elderly persons and a higher and earlier mortality rate26. Psychological disturbances such as depression are also found to be higher in poorly sighted elderly persons in comparison with their normally sighted counterparts27. This could be due to social isolation as a result of visual impairment. There is thus the need to enable older people perform their activities of daily living independently with minimal or no intrusion. This can be achieved by preserving or restoring good vision. The systemic and ocular co- morbidities found in the study are also mostly age related occurrences. These findings are similar to recent studies conducted in other parts of Nigeria11,15,17.

This study found the major retinal diseases to be age related macular degeneration, vascular conditions such as diabetic retinopathy, hypertensive retinopathy and retinal vascular occlusions, retinal detachments/breaks, macula holes and inflammatory chorioretinitis. These conditions have also been documented to be the leading causes of retinal diseases among more recent studies in Nigeria11,15^-17. However, studies conducted over three decades ago in this region, reported the presence of macular degeneration while vascular conditions such as diabetic retinopathy and vascular occlusions were rare9,10. This is thus at variance with a much earlier report that macular degeneration is uncommon in blacks28. More recent studies also show that ARMD is a common retinal disease among Nigerians11,15^-17. The increasing incidence of retinal vascular diseases such as diabetic retinopathy and vascular occlusions may be due to increase in the risk factors for these vascular diseases such as diabetes and hypertension with increase in non-communicable diseases attributed to increasing urbanization and changes in lifestyle6,7,16. Sickle cell retinopathy occurred in 1.6% eyes which is less frequent compared to studies from Western Nigeria10,16. This may be due to the fact that haemoglobin C genotype (HbSC), known to cause more ocular complications occurs more commonly in the western part of Nigeria than haemoglobin S genotype (HbSS)

Retinal detachment is a treatable cause of visual loss and prognosis depends to a large extent on early intervention. Its presentation in developing countries differs from that in industrialized countries29. Late presentation is a common occurrence in this region18,29^-33. There is need to create awareness so that scleral buckling can be easily performed when patients present early to restore vision as delayed presentation results in less success rates after surgery and need for vitrectomy. Facilities for vitrectomy and treatment of complicated and long standing retinal detachment are limited, expensive with little or no provision for maintenance and repair services when they break down. This further reduces the number of patients who can access it.

A positive family history of retinitis pigmentosa was documented in only one case. Higher incidence of hereditary retinal disorders is more common in societies were consanguineous marriages are practiced34. Toxoplasmosis was the most common inflammatory retinochoroiditis documented. There is need for availability of facilities for serology and complete laboratory work up as the diagnosis of toxoplasmosis was presumed based on characteristic clinical signs without confirmatory serology. Toxoplasmosis is endemic in this environment and its confirmatory serological studies are expensive and not widely available9,11,22. This use of clinical parameters to make diagnosis and initiate treatment can be utilized in the absence of confirmatory investigations in endemic areas35.

Vitreo-retinal diseases should also be given importance and priority in the elimination of avoidable blindness in developing countries as has been successfully performed for cataract, trachoma, corneal opacity from vitamin A deficiency and onchocerciasis. Many of the causes of visual loss in vitreo-retinal diseases in developing countries are also avoidable being either treatable with early intervention such as inflammatory retinochoroiditis, retinal detachment, macula hole, neovascular age related macular degeneration and diabetic retinopathy or preventable/ modifiable with dietary supplementation and life style modifications in conditions such as diabetes, hypertension and age related macular degeneration6^-8,36. Low vision and rehabilitation services can be offered to patients with irreversible low vision and blindness to improve their quality of life. There is need for increased advocacy so that administrators, health care planners and health care providers should ensure ready availability of facilities for vitreoretinal services such as lasers for proliferative retinopathies, vitrectomy machines and operating microscopes with accessories for vitreoretinal surgeries such as retinal detachments, macula holes, vitreous haemorrhage and dislocated lenses e.t.c. and pharmacotherapeutic agents such as intravitreal antivascular endothelial growth factors to reduce the burden of blindness from these conditions as has been successfully performed for cataract, trachoma, corneal opacity from vitamin A deficiency and onchocerciasis.