|Year : 2017 | Volume
| Issue : 2 | Page : 84-88
Aphakia: A 5-Year review at Barau Dikko Teaching Hospital, Kaduna, North-west Nigeria
Amos Bakut Silas
Department of Ophthalmology, Barau Dikko Teaching Hospital, Kaduna State University, Kaduna, Nigeria
|Date of Web Publication||30-Apr-2018|
Dr. Amos Bakut Silas
Department of Ophthalmology, Barau Dikko Teaching Hospital, Kaduna State University, Kaduna
Source of Support: None, Conflict of Interest: None
Aim: To describe the causes, visual potential and the proportion of aphakics that can be prevented from being blind in BDTH, Kaduna. Method: A retrospective review, the records of all aphakics that had refraction from January 2011 and December 2015 was retrieved from the refraction unit of our hospital. Patient's biodata, presenting visual acuity, corrected visual acuity, spherical correction and diagnosis were extracted and analyzed using SPSS version 20. Outcome Measures: Presenting visual acuity, corrected Visual acuity and spherical correction. Results: In 5 years, 56 eyes of 42 patients were refracted, with a mean age of 68.9years, 24 (54.8%) were males and 19 (42.2%) were females. Aphakia was caused by surgery in 29 (51.8%), couching in 23 (41.1%) and trauma in 4 (7.1%). Most eyes were corrected with +10D lens and aphakic spectacles could prevent 45 (83.4%) eyes from blindness. Visual outcome depended on the aetiologic cause of aphakia. Conclusion: There are still a few patients blind from aphakia mainly following cataract surgery. Adequate refraction and provision of spectacles can prevent blindness in a large proportion.
Keywords: Aphakia, cataract, couching, refractive error, trauma
|How to cite this article:|
Silas AB. Aphakia: A 5-Year review at Barau Dikko Teaching Hospital, Kaduna, North-west Nigeria. Arch Med Surg 2017;2:84-8
| Introduction|| |
The crystalline lens is an important component of the refractive media of an eye that directs light to the retina. Absence of the crystalline lens termed aphakia can arise from congenital or acquired causes; from trauma, surgery, or couching – a traditional means of treating cataract by bluntly displacing the lens into the vitreous. Aphakia causes a refractive error, and it is the second most treatable cause of blindness after cataract surgery.
Studies on aphakia had reported prevalence of 0.04%–0.05% (visual acuity [VA] <3/60) and 0.06%–0.19% (VA 6/60). In some African countries, aphakia was found to be the major cause of blindness. In Nigeria, a national survey carried out in 2006 found couching to be one of the major methods used for cataract removal and was associated with poor outcome. This suggests that visual impairment from aphakia will continue to be an issue in the elderly until such a time standard cataract surgery with intraocular lens (IOL) implantation is available to all persons in need.
Fortunately, visual impairment from uncomplicated aphakia is correctable. The use of spectacles is the oldest means of correcting aphakia and dates back to centuries, but problems of “Popeye” appearance of patients, 35% magnification, ring scotoma, and decrease field of view discouraged its use. Contact lenses are another means of correcting aphakia and are superior to spectacles because the retinal image is almost the same size as before cataract surgery. However, because of their thickness, fitting is not easy; they also impede oxygen exchange and are quite expensive. The third means of correction is IOL implantation; this is considered the best method of aphakic visual correction because the implanted lens is almost at its natural anatomic location.
Although the use of IOLs to correct aphakia has become routine since 2000 in our center, Barau Dikko Teaching Hospital (BDTH), Kaduna, Nigeria, we still see people with aphakia in one or both eyes. These are mainly patients who have had their eyes couched as couching is still a common practice in some rural parts of Nigeria, constituting over 40% of cataract interventions. There were also aphakia that results from planned intracapsular cataract extraction (ICCE), unplanned ICCE due to surgical complications, or extracapsular cataract extraction without IOL. Other aphakic patients were those who have had ICCE over decades before IOL surgery became common in Nigeria. We report here the causes, visual presentation, and proportion of aphakic eyes whose vision can be improved with the use of simple spectacle correction at the eye clinic of BDTH, Kaduna, Nigeria.
| Methods|| |
This is a retrospective review of aphakic patients seen in the eye clinic at BDTH, Kaduna, from January 2011 to December 2015. The Ophthalmology Department is manned by four ophthalmologists, two optometrists, ophthalmic nurses, and other support staff.
Ethical clearance for the study was obtained from the Ministry of Health, Kaduna State, before the ethical committee of the hospital was constituted.
Inclusions in this study were any person with aphakia in one or both eyes that presented to the outpatient of BDTH during the study period and any person who had planned or unplanned ICCE or ECCE without IOL surgery in one or both eyes at the BDTH during the study period. Exclusions were those with a history of couching but had corneal scars that prevented slit-lamp confirmation of aphakia.
All patients who presented to the outpatient clinic had their VA measured in each eye by the nurses using Snellen's chart placed at 6 m or less. If vision was <3/60, it was assessed by the ability to count fingers, see hand movement, or ability to perceive light. In all patients whose unaided VA was <6/9, a pinhole was used to check for improvement after which all patients were seen by the ophthalmologist. The ophthalmologist examines all patients including funduscopy and slit-lamp examination to identify patients with aphakia in one or both eyes. All those with aphakia were referred to the optometrist for refraction. Objective refraction was done with the aid of either an autorefractor or retinoscopy and subsequently refined using different trial lenses to get the best subjective correction. The optometrist entered the patients' bio-data, diagnosis as made by the ophthalmologist, presenting VA, spherical correction, and corrected VA and thereafter referred the patient back to the ophthalmologist. The ophthalmologist assessed the refraction and recommended correction to the patient. Patients who had unplanned ICCE, planned ICCE or ECCE without IOL at our hospital, were included during their first postoperative follow-up. They followed the same procedure as the outpatients outlined above.
The optometrist record book was used to identify patients who were refracted for aphakia from January 2011 to December 2015. The patient's age, sex, laterality, cause of aphakia, entry VA, corrected VA, and subjective corrective lens powers in diopters (D) were noted and entered into a data sheet.
After manual cleaning and coding, the data were entered into and analyzed using SPSS version 20 (IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY, USA: IBM Corp.) Measures of central tendency were calculated for quantitative variables and frequencies for quantitative variables; frequency table was used to establish the frequency distribution. Means and standard deviations of some variables were also determined.
Outcome measures were presenting VA, corrected VA, and spherical correction.
Cataract surgery was defined as an operation for cataract extraction performed by a trained ophthalmologist in a normal theater setting.
Couching was defined as any procedure performed to dislocate the lens in a traditional setting.
Categorization of outcome was based on the WHO standards:
- Good vision: VA of 6/18 or better
- Borderline vision: VA of 6/24–6/60
- Poor vision: VA <6/60.
| Results|| |
Over the 5-year period, 56 aphakic eyes of 42 patients were seen. There were 23 (54.8%) males and 19 (45.2%) females. Of these, 33 (58.9%) right eyes and 22 (39.3%) left eyes were refracted. The mean age of patients was 68.9 ± 14.7 years ranging between 13 and 90 years. Age and sex distribution are shown in [Table 1].
|Table 1: Age and sex distribution of patients who were refracted with aphakia in the 5 years|
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The causes of aphakia were surgery 29 (51.8%), couching 23 (41.1%), and trauma 4 (7.1%). The causes of aphakia from surgery were unplanned ICCE from complications of rent and vitreous loss 14 (48.28%) eyes, planned ICCE from normal lens 10 (34.48%), and planned ICCE from lens displacement 5 (17.24%).
The pattern of spherical correction was +8.0 D, 1 (1.8%); +10.0 D, 47 (83.7%); +11.0 D, 8 (14.3%), respectively.
Two eyes of a patient presented with VA of 6/24 and 6/36 and another patient with unilateral aphakia presented with 6/36. Presenting and corrected VAs of eyes of the study patients are shown in [Table 2].
|Table 2: Presenting and corrected visual acuities of eyes of study participants|
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After correction, VA improved in 51 (91.07%) eyes. Of these, 31 (55.5%) eyes had good outcome vision consisting of 22 (75.9%) eyes that had cataract surgery and 9 (39.1%) eyes that were couched. There was no vision improvement in any of the eyes that had trauma. Six eyes (10.7%) were fully corrected to 6/5 and 6/6, one (1.79%) of which was couched.
Eleven eyes had poor vision after correction. These comprised 1 (3.4%) eye that had cataract surgery, 6 (26.1%) eyes that were couched, and 4 (100%) eyes that had trauma. Corrected visual outcome by etiology of aphakia is shown in [Table 3].
| Discussion|| |
Aphakic blindness is a major issue, especially in some African countries like Nigeria where most advanced means of cataract surgery is not easily accessible. Various reports have been made regarding aphakia caused by couching in Nigeria. In this present study, 56 eyes of 42 patients from all causes of aphakia were studied in the eye clinic of the BDTH.
The mean age showed that aphakia is a condition of the aging population. The reason is most likely due to cataract being a cause of lens removal predominantly among the elderly. Another reason may be because couching is performed on relatively hard lens found only in elderly eyes than the soft lens of the young that cannot withstand couching.,,
In this study, three causes of aphakia were identified: cataract surgery, couching, and trauma. No case arising from a congenital cause was found even as the clinic is a referral center for congenital cataract and has performed about 200 congenital cataract surgeries from 2010, suggesting that congenital aphakia is a rare presentation in our hospital. The most common cause of aphakia was cataract surgery followed by couching and trauma. The Nigerian National Blindness Survey identified couching as the major means of cataract removal in Nigeria with the northwest having the highest burden; this study found that cataract surgery was a more common cause of aphakia than couching; the reason for this may be because this study is a hospital-based study and patients couched in their homes would normally not attend hospitals. Patients who become aphakic in hospital will return to the hospital for correction of their aphakia while those couched are more likely to remain in their communities where they were couched.
Gender issues in eye care came to prominence when it became the theme of 2009 World Sight Day. The theme sought to highlight the fact that two-third of blindness was in women and that there was gender disparity in uptake of services. Solutions offered to overcome this included bringing service and women together, counseling family members, and women to reach women. Almost a decade later, this study found aphakia was distributed in 54.8% males and 45.2% females, with majority of all causes of aphakia 52 (92.9%) related to cataract interventions: cataract surgery and couching. Epidemiologic studies showed higher prevalence of cataract in women,,, but services are accessed more by men.,,,, A study in Northern Nigeria reported couching coverage of 19.1% males and 16.6% females and cataract surgical coverage of 5.3% males and 2.6% females. This disproportionate gender utilization of cataract services suggests why there are more males than females with aphakia in this study. The explanation for the gender differences in utilization of services has been related to cultural, social, and economic factors that favor men.,,,
Cataract-operated patients are either pseudo or aphakic estimated at 6.1 m (5.1%) in the USA and was expected to rise to 9.5 m by 2020 because of the expected increase in a number of people with cataract. The prevalence of aphakia after cataract surgery was reported by Lundström et al. to be 0.65%. The national survey in Nigeria reported that 41.1% of cataract surgery/interventions had IOL, suggesting that 68.9% were aphakic including couching. In this study, aphakia from cataract surgery alone was 29 (51.8%), out of which 14 (50%) were unplanned, meaning that there were complications of surgery: rent and vitreous loss. A giant rent cannot support a posterior chamber IOL; hence, some surgeons leave the patient aphakic for secondary implantation of IOL. This is the predominant cause of aphakia in developed countries reported at 87.5% because they have overcome couching and transited from non-IOL ICCE surgery long ago. In Nigeria, the transition to IOL surgery was late, first reported by Agbeja  in 1994 and in Kaduna by Adejor  in 1997. We therefore still see a significant proportion of planned aphakics that were operated by ICCE, 10 (34.48%) eyes in the present study.
Another type of planned aphakia after cataract surgery noted in this study was caused by preoperative lens displacement, which was found in 5 (17.24%) eyes similar to Lundström et al.
About 90% of eyes in this study presented blind, but three eyes of two patients presented with borderline vision (6/36 and 6/24). The high rate of blindness is because aphakia causes extremely high hypermetropia. Other studies have reported similar high rate of blindness in uncorrected aphakia.,, The three eyes with borderline presenting vision are most likely myopes because correction of myopia is partly achieved with lens extraction which involves weakening the refractive state of the eye.
Forty-seven (83.7%) eyes were corrected with + 10 D sphere. This finding is consistent or similar with reports from other studies in India and Nepal., Overall, vision after correction improved in 51 (91.1%) eyes. In comparison, another study  carried out in Ilorin, Nigeria, reported improvement in 66.6% of eyes. Only 31 (55.4%) eyes in this study achieved good (6/18 or better) and 14 (25%) borderline vision using +10 D spherical correction. This shows that by correcting aphakia with spectacles, contact lens, or IOL implantation, the burden of blindness contributed by aphakia could be reduced by 80.4% in our setting.
The proportion of eyes that achieved good vision after correction was higher following cataract surgery 22 of 29 (75.9%) than in couching, similar to what has been reported by Kapoor et al. in India and least in trauma. The reason is that ocular trauma may be associated with other tissue damage  that may contribute to vision loss. Other reports on good vision after correction of couched eyes have been reported by other authors in Nigeria.,, Couching has been associated with high rate of complications such as vitreous opacities, hyphema, vitreous hemorrhage, glaucoma, and cystoids macular edema.,, Yet couching is seen in a large proportion of aphakics which may be due to association with. This may be associated with poverty, rural dwelling, ignorance, and high cost of conventional surgery, and the readily available couching services within the communities were cataracts abound in addition to negotiating and accepting their reward in kind as well.,,,,,,,
Six eyes were fully corrected to 6/6, one (16.66%) of which was a couched eye. A study carried out by Schrader  on couched eyes in Northeast Nigeria, and a demonstrated modified couching by use of alpha-chymotrypsin to break the zonules and a frozen probe to dislocate the lens by Girard showed that a properly carried out couching can have better results than a poor surgery. However, the overall success of couching carried out mostly by itinerants who provide minimal postoperative care is not comparable to modern surgeries in terms of visual outcome and complications.,,
| Conclusion|| |
Most aphakics are blind, and cataract surgery is the most important causative factor. Corrective measures such as spectacles, contact lenses, and refractive surgery will prevent this blindness.
Special thanks to Prof. Caleb Mpyet and Dr. Rabiu Mansur M for their contributions.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]