Axial length/corneal radius of curvature ratio and refractive status in an adult Nigerian population.

AIM/BACKGROUND: Associations between axial length (AL) to corneal radius of curvature (CR) ratio and refractive status in a healthy Nigerian adult population were studied. MATERIALS AND METHODS: Healthy students and members of staff of Obafemi Awolowo Teaching Hospitals Complex, Ile-Ife, South West Nigeria, free of obvious ocular diseases except possible refractive errors were recruited. Consecutive consenting volunteers were recruited by simple random sampling and a proportionate sample of each population based on its representative fraction in the hospital community was recruited. The study was conducted between June and August 2011. Noncycloplegic objective refraction was done and spherical equivalent refraction (SER) of the right eyes was used for calculation. The AL, CR, and keratometric readings were measured with the IOL Master. The AL/CR ratio was calculated. The data were analyzed with statistical software package STATA 13. RESULTS: Three hundred and fifty volunteers aged 18-60 years were studied. The mean ± standard deviation of AL/CR and SER were 3.04 ± 0.10 and -0.38 ± 1.42D, respectively. AL in myopia was significantly higher than in emmetropia and hypermetropia. There were no significant differences between CR in the refraction groups. Myopes had significantly higher AL/CR than nonmyopes. On controlling for age and gender, 1 mm increase in AL increased SER by -0.77D (95% confidence interval [CI] -0.91--0.64D) while a unit increase in AL/CR increased SER by -8.89D (95% CI -10.00--7.78D). Whereas AL accounts for 39% of variability in SER (P < 0.001), AL/CR accounts for 51% of the variability observed in SER (P < 0.001). CONCLUSION: This study has further confirmed that the AL remains a strong determinant of refraction, but a derived factor AL/CR accounts for more variation in final refractive status than AL in isolation.

Case control study of dry eye and related ocular surface abnormalities in Ibadan, Nigeria.

BACKGROUND: Tear instability is associated with symptoms of ocular discomfort and irritation. Many patients with dry eyes remain untreated due to improper diagnoses. OBJECTIVE: To identify symptoms and surface abnormalities associated with dry eyes. MATERIALS AND METHODS: One hundred and fifty-six eyes of 78 subjects attending the Eye Clinic of the University College Hospital Ibadan were screened for dry eyes/tear instability using rose Bengal stain (graded 0-9), tear break-up time (TBUT), Schirmer's 1 tests, tear meniscus height and a standardised symptoms questionnaire. Grades 4-9 rose Bengal staining were considered as positive dry eye and were compared with grades 0-3 staining eyes as negative controls. RESULTS: Mean tear meniscus height, Schirmer's test and TBUT were lower among cases than their corresponding control eyes. The difference between the mean Schirmer's test values of cases and their controls were statistically significant (P = 0.00 for right eyes and P = 0.002 for left eyes). Rose Bengal grades were inversely correlated with the mean Schirmer's values (Pearson correlation -0.429, P = 0.05 for right eyes and -0.335, P = 0.03 for left eyes) and TBUT (Pearson correlation -0.316, P = 0.05 for right eyes and -0.212, P = 0.06 for left eyes). About 95.8% of the cases were symptomatic, as opposed to 70.4% of the controls (P = 0.01, Fisher's exact test) and 95.8% of dry right eyes compared to 61.1% of their controls had ocular surface abnormalities (P = 0.001), while 89.5% of dry left eyes compared to 62.7% of controls had surface abnormalities (P = 0.07). CONCLUSION: A close relationship exists between ocular irritation symptoms, surface abnormalities and functional evidence of tear instability. Such patients should be treated empirically or screened for dry eyes.

Visual function survey of commercial intercity vehicle drivers in Ilorin, Nigeria.

OBJECTIVE: To determine the prevalence of visual impairment among commercial intercity vehicle drivers (CIVDs) in Ilorin, Nigeria. DESIGN: A cross-sectional descriptive study. PARTICIPANTS: Among the estimated 450 drivers operating in 5 motor parks for CIVDs in Ilorin, 399 drivers participated in the study. METHODS: A structured questionnaire was administered at the motor parks to consecutive and consenting drivers, and basic ocular examinations were done. RESULTS: Using the Federal Road Safety Commission's requirement for commercial drivers in Nigeria, the prevalence of drivers with inadequate visual acuity (VA) was determined to be 11.5%, and 3.3% had monocular blindness. The prevalence of abnormal colour vision and visual field loss was 4.3% and 5.5%, respectively. There was no statistically significant relationship between visual impairment (VA and visual fields) and involvement in road traffic accidents (p > 0.05). Uncorrected refractive error, cataract, and glaucoma were the commonest causes of visual defects. Three hundred thirty-seven drivers (84.5%) did not have their eyes tested at first licensing and 370 drivers (92.7%) did not have testing at least once during renewals. CONCLUSIONS: A significant number of CIVDs in Ilorin are operating with VA that is far below the expected for their class of licence, and another unacceptably high percentage did not undergo any form of ocular examination prior to obtaining their driving licence. There is a need for renewed efforts to enforce a compulsory basic ocular examination for all prospective commercial drivers, and to ensure that the visual requirement for driving is met.

Causes of blindness in Southwestern Nigeria: a general hospital clinic study.

PURPOSE: This hospital-based study was carried out to assess the common causes of blindness in Ibadan, the largest city in the southwestern part of Nigeria, and to strengthen the primary eye care approach to control and reduction of cases of blindness in the community. METHODS: Following Hospital Ethical Board approval and informed consent of participants, a prospective study was performed in which 1,544 consecutive patients with bilateral or unilateral blindness seen between January and December 2003 at the Ring Road State Hospital, Ibadan, Nigeria, were evaluated for causes of blindness. Visual acuity was measured with an illuminated Snellen chart placed 6 meters away from the participants. This was followed by pen torch examination and dilated funduscopy with a direct ophthalmoscope. Friedman field analyzer was used to measure visual field. Patients with corrected visual acuity of less than 3/60 in the better eye or with visual field of less than 10 degrees from fixation were considered blind according to the World Health Organization criteria. RESULTS: The 1,544 patients had a mean age of 53.5 years (range, 4 to 96 years); 858 (56%) were male and 686 (44%) were female. Blindness was bilateral in 471 (30%) patients and unilateral in 1,073 (70%). When those persons with unilateral and bilateral blindness were grouped together, individuals within the 60 to 79 years age bracket were 667 (44%) and constituted the largest group of all blind persons. The leading causes of bilateral blindness were cataract, 171 (36%); glaucoma, 138 (29%); and optic atrophy, 21 (4%). The most common causes of unilateral blindness were cataract, 446 (41%); glaucoma, 213 (20%); and those referable to trauma, 116 (11%). CONCLUSIONS: Cataract and glaucoma are the main causes of bilateral and uniocular blindness in the study area.

The aetiology of optic atrophy in Nigerians--a general hospital clinic study.

This study aimed at reviewing cases presenting with optic atrophy at the eye clinic of the University College Hospital, Ibadan, Nigeria with a view to identifying some of the diagnostic problems. The study was a retrospective review of 100 cases selected by systematic random sampling method of a total of 6160 patients presenting with optic atrophy to the eye clinic over 6 years (April 1990 to March 1996). Diagnosis was based on ophthalmoscopic appearance of optic disc corroborated with visual field studies. The mean age of the patients was 40.8 years. The male to female ratio was 2:1 bilateral. Eighty percentages were bilateral, whereas 20% were unilateral. Only in 38% of cases could the cause of the optic atrophy be identified. The most frequently diagnosed were cranio-orbital neoplasms (8%), those referable to trauma (8%), hydrocephalus (7%), retinitis pigmentosa (3%) and post infectious (2%). Other causes include toxins, congenital, seizure disorders, birth asphyxia and papilloedema. In 62% of cases, the aetiology cannot be satisfactorily elicited. Some suggestions have been made to overcome some of these diagnostic problems.

Prevalence and causes of blindness and visual impairment among school children in south-western Nigeria.

The aim of the study was to assess the prevalence and identify the causes of blindness and visual impairment in school children of Ilesa-East Local Government Area of Osun State, Nigeria. A total of 1144 school children in primary and secondary schools were selected using a 2-stage random sampling method and examined to determine the prevalence and causes of blindness and visual impairment. A total of 17 (1.48%) children were blind or visually impaired. These comprised of 11 (0.96%) children who were visually impaired and 4 (0.3%) who were severely visually impaired. Only 2 (0.15%) school children were blind. The causes of visual impairment were refractive error 10 (0.87%) and immature cataract 1 (0.08%), causes of severe visual impairment included corneal opacities 2 (0.2%), amblyopia leading to squint 1 (0.08%) and 1 cataract 1 (0.08%). The causes of blindness in school children were corneal scars presumed to be due to vitamin A deficiency 1 (0.08%) and keratoconus 1 (0.08%). Causes of blindness and visual impairment in children attending regular schools in Nigeria were treatable. Prevention, early recognition and prompt treatment of these diseases by regular screening of school children would definitely reduce unnecessary visual handicap in Nigerian school children so that they can attain their full potential in the course of their education. Also, information from this study is relevant for the purpose of planning eye care programmes for the prevention of blindness in Nigerian school children. This will go a long way in the prevention of unnecessary blindness and visual impairment in school children.

Eye diseases in general out-patient clinic in Ibadan.

BACKGROUND: Eye diseases constitute one of the commonest problems presenting to the general practice clinic. This study was carried out to determine the pattern of eye diseases presenting to the general out-patient clinic and compare it with those in the ophthalmic clinic. METHODS: All patients presenting to the general out-patient clinic of University College Hospital, Ibadan with ocular problems from July to December 1989 were studied. A structured questionnaire was administered for personal, epidemiological and medical background information. Ophthalmic assessments were done by both the general practitioner and the ophthalmologist. RESULTS: A total of 3856 new patients were seen in the general out-patient clinic during the study period. Out of this 482 presented with ocular problems with a male to female ratio of 1.4: 1.0. Conjunctivitis (32.9%), cataract (14.7%), ocular injuries (12.8%), refractive errors (9.9%) and glaucoma (5.3%) were common eye conditions. Diseases of ocular adnexa, scleritis, aphakia and orbital tumours were rare. CONCLUSION: The pattern of eye diseases differed slightly from that presenting in the ophthalmic clinic. It is important that the general practitioner be conversant with common eye conditions presenting to him to enhance better management and reduce unnecessary referrals to ophthalmologists.

Prevalence of atopic diseases in Nigerian children with vernal kerato-conjunctivitis.

A descriptive study of 117 cases of vernal kerato-conjunctivitis (VKC), in children below the age of 18 years, newly presenting to 2 hospitals in Ibadan, Nigeria. All the children had a structured questionnaire administered to them which inquired about demographic and clinical, especially history or presence of other atopic diseases amongst other things. Specifically inquired about were asthma, eczema, allergic rhinitis or hay fever, allergic skin rash e.g. scabies, reaction to drugs and others. The children were also examined to confirm or detect the presence of these atopic diseases. The overall prevalence of atopic conditions was 19.8% amongst cases of VKC. These comprised of 6% asthma, 5% allergic rhinitis and 4.3% eczema. (Total 15.5%). Other forms of atopic conditions like other non-specific allergic skin reactions (0.9%), reaction to certain drugs e.g. chloroguine (0.9%) and other unknown allergic conditions (2.6%). It is suggested that children with VKC should be subjecteed to detailed enquiry and examination with regards to the presence of other atopic conditions. This will go a long way in understanding the type(s) of allergic response involved and perhaps of management of VKC.

Conjunctival impression cytology and biochemical assessment of vitamin A status in Nigerian children.

The study was part of a national survey designed as cross-sectional population survey to estimate the prevalence of Vitamin A deficiency in Nigeria. A multistage cluster random sampling technique was used to select about 163 children between 6 and 71 months of age in 2 health zones of Nigeria, for assessment of their vitamin A status. Conjunctival Impression Cytology (CIC) was compared with biochemical method by estimating serum level of vitamin A using the reverse phase high pressure liquid chromatography (HPLC). Conjunctival impressions were taken from both temporal bulbar conjunctivae of 483 children using the disc applicator. CIC showed significant association with low serum retinol (0.70 umol/l) levels. Children with abnormal CIC had 2.6 times the risk of having low serum retinol levels compared with those with normal CIC (OR = 2.6, 95% C.I = 1.03-6.67). When CIC was classified as normal and abnormal at cut off points of retinol at 0.70 and 0.35 umol/l, the sensitivity of CIC remained low, while the specificity remained high. Although our study did not demonstrate valuable use of CIC as a screening tool under field conditions in a tropical environment like Nigeria, our impression is that, if the technique is further refined and evaluated, there is a high potential for its use in developing countries, because of its simplicity, practicability and non-invasiveness.

Assessment of educational services available to blind and low vision school children in Lagos, Nigeria.

A descriptive study to assess the educational services available to children attending the Pacelli School for the Blind in Lagos, Nigeria. A standardised methodology was used with structured and semi-structured questionnaires. Observations were also made in some areas. Of the 26 children aged 10-15 years who were identified as having low vision, 15 (57.7%) of them had significant improvement in distance and near vision after refraction while one third (31%) had improvement in their reading with low power magnifying lenses. All except 4 (25%) teachers were well educated but none seemed to have appreciable knowledge about the teaching of low vision children as all these children were taught Braille like their blind peers. While educational facilities available were reasonably adequate for blind children, no visual aids were available for low vision children. It is recommended that appropriate educational facilities, optical and non-optical devices should also be provided particularly for low vision children to enable them achieve their optimal potential in life.

Causes of low vision and blindness in children in a blind school in Lagos, Nigeria.

A descriptive study to determine the causes of low vision and blindness in children attending the Pacelli School for the Blind in Lagos State, Nigeria. A standardised methodology was used with structured and semi-structured questioinaires. Twenty-six children aged below 16 years who were identified as having low vision and blindness were examined to determine the causes of the low vision and blindness. The anatomical sites of diseases leading to low vision and blindness in these children were retina (30.8%), lens (23.1%), glaucoma (19.2%), cornea (11.5%) and optic nerve (7.7%). Aetiologically, 38.5% of low vision was due to hereditary factors, 23.1% intra-uterine, 15.4% others and unknown in 23%. Retinal dystrophy was the most common cause of low vision and blindness, while congenital cataract and glaucoma were the major causes of avoidable blindness. Very few cases of corneal scar (Measles/Vitamin A deficiency) were seen. The causes of low vision appeared to be different from those of blindness as hereditary and intra-uterine factors were mainly responsible for low vision. It is recommended that these children be identified early, through low vision care programmes and those with avoidable causes treated accordingly.

Childhood eye diseases in Ibadan.

Eye diseases in 1028 children below 15 years of age, seen at the Eye clinic of the University College Hospital, Ibadan, Nigeria were studied. Refractive error, vernal conjunctivitis, measles keratitis associated with malnutrition and those referrable to injuries were leading causes of eye problems amongst children. Diseases of ocular adnexa (excluding orbital cellulitis) squints, glaucoma, uveitis and trachoma were rare.

Aneurysm of the vein of Galen presenting with proptosis.

A case of proptosis, arterio-venous malformation and aneurysm of the Vein of Galen in a 12 year old schoolboy is presented. This is in addition to the literature of the rare aneurysm involving the Great Vein of Galen. This is the first time this syndrome will be described in association with ophthalmic presentation. It is however remarkable that with such a huge sized aneurysm and A-V malformation, the patient did not have any other neurological deficit except visual field loss. Perhaps the previous series had undetectable visual field loss which was missed as patients might not have complained of visual symptoms.

Malignant melanoma of the eyelid in the black. Case report.

A case of malignant melanoma of the eyelid is presented in addition to the literature of this rare eyelid malignancy in the negro. Its epidemiology, clinical features, diagnosis and treatment are discussed to create more awareness of the occurrence of this tumour especially in the black race.