Abstract
Abstract
Objective
To compare the presenting demographic and clinical characteristics of rhegmatogenous retinal detachment (RRD) with other RD types, investigate risk factors of blinding RD and the outcome of surgical intervention.
Design
Prospective, cross-sectional and multicentre.
Setting
Four ophthalmic centres in three geographic locations of Nigeria.
Participants
264 eyes from 237 patients diagnosed with RRD, tractional retinal detachment (TRD) and exudative retinal detachment (ERD) seen between April 2019 and March 2020.
Results
264 eyes of 237 patients were diagnosed out of 35 641 patients screened. RRD was the most common RD (n=167 (70.5%), TRD 61 (25.7%) and ERD 9 (3.8%) patients). The hospital-based prevalence of all RD is 6.6 per 1000 patients (0.66%), and for RRD alone, 4.7 per 1000 patients (0.47%). The most common symptom was a sudden decline in vision, 100 patients (42.2%); floaters and flashes were uncommon, 5 (2.1%). RRD presented earliest, with a median symptom duration of 2 months, and TRD and ERD at 7.5 months each.
The 46–65-year age group had the highest representation, RRD (n=70, 41.9%), TRD (n=41, 67.3%), ERD (n=4, 44.4%). The mean age was highest in TRD (52.3±12.7 years) and lowest in RRD (44.0±17.5 years) and ERD (45.2±20.4 years). Males dominated (RRD 70.1%, TRD 62.3%, and ERD 66.7%). Ocular trauma was highest in RRD 29.3%, TRD 7.5% and ERD 10%; fellow eye RD was highest in TRD 47.5%, ERD 20%, RRD 8% and myopia was highest in RRD 27.6%.
Two-thirds of eyes were blind (Snellen best-corrected visual acuity <3/60). Risk factors are prolonged symptom duration (p=0.03), ocular surgery (cataract surgery) (p=0.04), extent of RD (p=<0.001), increased quadrants of RRD (p=<0.001), macula involvement (p=<0.001), advanced proliferative vitreoretinopathy grade (p<0.004) and lattice degeneration (p<0.03). For all RD, previous intraocular surgery increased the risk of blindness by 2.1 times. Total RD raised the odds of blindness more than 16-fold. Involvement of more quadrants by RD increased the risk by 12 times compared with single-quadrant RD. Macular off RD had an 18-fold higher likelihood of blindness than macular on. Each additional year of age and each extra month of symptom duration increased the risk of blindness by 1.0%. Symptoms lasting over 6 months doubled the odds of blindness.
Shorter symptom duration is associated with better preoperative and postoperative vision. In contrast, longer durations are connected to poorer outcomes. Eyes with symptoms lasting less than a week had a 17% rate of postoperative blindness, compared with 30% in cases lasting 1–3 months, and 51% in cases exceeding 6 months.
Conclusions
Delays in diagnosing and treating RD result in high rates of preoperative blindness, which can be reversed with surgery even after several weeks of symptoms. Understanding the associations between RD and the risk of blinding RD in developing countries will benefit early diagnosis, treatment and improve treatment outcomes.
Keywords: Vetreoretinal, Diabetic retinopathy, Ophthalmology
Strengths and limitations of this study.
This prospective, multicentre study involves a substantial number of retinal detachment cases and is the largest of its kind in Nigeria and West Africa.
The risk factors for blinding retinal detachment were analysed using a regression model, providing valuable local insights into the level of risk associated with each factor—a perspective not previously described in any Nigerian or African retinal detachment study.
A comprehensive analysis was conducted to examine the impact of retinal detachment duration on initial vision at presentation and postoperative outcomes, revealing significant findings that had not been previously reported in the region, and these insights were gained through a retrospective review of the surgical outcomes of research participants, evaluated 4 years after the initial data collection.
Due to the study’s cross-sectional design, it was not possible to conduct a longitudinal follow-up to track the clinical progression of the RD eye or the fellow eye, potentially resulting in incomplete data on the full extent of the risk’s impact on the eyes and vision.
The hospital-based study and reliance on patient reporting of certain information, including symptom duration and medical history, may introduce bias related to overestimating RD incidence and recall errors, respectively.
Introduction
Reports on retinal detachment (RD) in Nigerians and Africans indicate that RD is the most common reason for vitreoretinal surgery, and many RD eyes are blind at presentation, making it a significant eye health concern.1 2 Out of 219 rhegmatogenous RD (RRD) eyes reported by Nkanga et al, 71.4% and 7.5% had blindness and severe visual impairment, respectively.1 Surgical intervention restores vision in RD cases, making it a valuable treatment option.2 As a result, there is a strong interest in RD research. Other studies on RD in Africans, except one from Ethiopia,3 have focused solely on RRD, which is the most common type of RD.2 4 5 In the Ethiopian study, 55 eyes (58.5%) had RRD, and 22 eyes (23.4%) had tractional RD (TRD).3 RRD occurs when a retinal break allows fluid into the subretinal space. TRD is caused by traction forces exerted by the vitreous on the retina that separate the retinal layers, and exudative RD (ERD), which results from a breakdown of the blood–retinal barrier leading to fluid accumulation in the subretinal space without a retinal break, has also been diagnosed in Nigerians.6,9
Okonkwo et al and others have demonstrated that RRD in Nigerians and Africans can be effectively treated, even in cases of delayed and complex presentation, with a high rate of anatomical success and improved vision.2 4 5 10 In these studies, despite the delayed and complex presentation of RRD, the outcomes of surgical intervention for RRD prevent blindness, highlighting the importance of this intervention. Therefore, surgery for RRD is rewarding. For this reason, RRD in Nigerians and Africans warrants further research to understand its associated factors and risks of blinding RD. Identifying these risk factors will aid in early diagnosis and pinpoint intervention points to further improve RD surgery outcomes in the Nigerian and African populations.
Previous reports on RD have been retrospective, considered only RRD and have been limited to experience from a single centre, which restricts the generalisability of the findings. We have conducted a prospective, multicentre study reviewing the clinical data at presentation for the three types of RD, with a focus on RRD, and we investigated the clinical features and risk factors associated with blind RD at presentation.
Methods
Our research was a multicentre, prospective, cross-sectional study that encompassed patients visiting ophthalmic clinics in four hospitals in Nigeria. Nigeria is segmented into six zones, broadly categorised by geographic location: North and South, with the South further subdivided into East, South and West, and the North into East, Central and West. The study involved one private hospital and three public hospitals with active ophthalmic clinics, situated in the North Central, South South and South West regions of Nigeria. The research was conducted over a 12-month period, from 1 April 2019 to 30 March 2020. At each of the four study sites, all ophthalmic patients were screened to identify those with RRD, TRD or ERD.
Eligibility criteria: Patients diagnosed with RD were eligible for the study; there were no exclusion criteria. The study included patients of all demographics and ages. A retina specialist at each of the four research sites confirmed the RD diagnosis.
RRD was diagnosed when a convex RD was present along with retinal break(s) and possibly retinal corrugations. A diagnosis of TRD was made if the retina was immobile, with concave contours and surfaces, fibrovascular membranes, neovascular tufts, areas of tractional detachments and subretinal bands. ERD was diagnosed in cases featuring a convex RD without a retinal break and lacking tractional elements in the vitreous or retina. There had to be no retinal corrugations, which indicate RRD. In some ERD cases, intraocular inflammation was present, with evidence of inflammation in either the anterior or posterior chamber. However, eyes with ocular inflammation, including vitritis where ERD was visible, were not excluded. When a fundal view was obstructed by opacity, a B scan was used for diagnosis.
Patients with RRD, TRD or ERD provided informed consent to participate in the study. We informed patients visiting the retina and ophthalmic outpatient clinics about the study and offered them the choice to participate or not. Those who agreed to participate signed a consent form. Parents or caregivers signed on behalf of minors.
Data were collected from consecutive patients diagnosed with RD who visited either the retina or general ophthalmic clinics. Initially, we obtained demographic data from patients reporting sudden or gradual vision loss and inquired about additional complaints or relevant history, including floaters, flashes of light, a veil-like covering or visual field defects (noted to suggest RD), as well as ocular trauma and prior intraocular surgeries such as cataract or glaucoma procedures. The duration of symptoms was carefully documented. Next, we documented a history of any associated systemic diseases, such as diabetes mellitus, hypertension, sickle cell disease and other significant contributory conditions. A comprehensive ocular examination was conducted, including visual acuity testing using a Snellen chart. The best-corrected visual acuity (BCVA) for each eye was assessed and recorded. Visual acuity was classified according to the International Classification of Diseases-10 (ICD-10) code for visual impairment: near normal/mild impairment (≥6/18), moderate impairment (6/24 to 6/60), severe impairment (<6/60 to 3/60) and blindness (<3/60 to no perception of light). Legal blindness was defined as a BCVA of <3/60 (Snellen acuity).11 Subsequently, slit lamp biomicroscopy was performed to examine the anterior segment of the eye and measure intraocular pressure. Dilated slit lamp funduscopy was carried out using either a 90D non-contact lens or a 20D lens in conjunction with binocular indirect ophthalmoscopy. Eyes with no view of the posterior segment were not excluded from the study. When media opacity obstructed fundal view, B-mode ultrasound scanning was employed to evaluate the posterior segment.
The assessed RD data included symptom duration, BCVA, extent of RD and macula status (either attached or detached). Additionally, information was gathered regarding prior trauma history, myopia, previous intraocular surgery, RD in the contralateral eye and characteristics of the RD. We also collected data on the recommended treatment, reasons for not treating and the availability of treatment equipment.
As a follow-up to this research, 4 years after collecting the initial data, we retrospectively reviewed cases of participants who had undergone treatment. We documented their treatment details, visual outcomes and follow-up durations. Additionally, we counted the eyes that received surgical intervention for RD and recorded their visual results at one and twelve months after surgery. We noted whether the postoperative vision at the last visit was improved, unchanged or reduced compared with the vision at initial presentation. The study also analysed the relationship between postoperative visual outcomes and symptom duration using the Kruskal-Wallis test, along with a regression model assessing the odds of blindness after surgery based on symptom duration.
Data for each participant were carefully recorded in a Microsoft Excel sheet, with data from all four sites electronically sent to the data collection centre at the end of each month. A trained data analyst compiled all the information. The principal investigator at each site was responsible for verifying the accuracy and integrity of the data, making sure reports were submitted on time, and sending the data to the centre monthly.
Data management statement
Age and duration of symptoms were summarised with means (SDs) and medians (IQRs), respectively. Categorical variables like gender, trauma history, myopia, previous intraocular surgery and systemic diseases were presented as counts and percentages. The associations between categorical variables and blindness were examined using cross-tabulations, with Pearson’s χ2 or Fisher’s exact test applied as suitable.
Comparisons of continuous variables between blind and non-blind eyes were performed using the Mann-Whitney U test for data that are not normally distributed (such as symptom duration) and the independent samples t-test for variables that follow a normal distribution (such as age).
Two logistic regression models were developed to assess how independent variables affect the likelihood of eyes being blind at presentation. The first model included both univariate and multivariate analyses for all the sampled 264 RD eyes, and the dependent variable was coded 1=blind, 0=not blind. The multivariate analysis controls for potential confounders. ORs and 95% CIs were reported for each predictor.
All analyses were conducted using IBM SPSS Statistics for Windows, V.22.0 (IBM). A p<0.05 was considered statistically significant.
Results
Demographics and clinical symptoms
We screened 35 641 patients in four ophthalmic clinics within the study period. A total of 237 patients were diagnosed with RD during the study period. The average age of the 237 patients diagnosed to have RD was 46.2±16.8 years (range from 6 months to 89 years). Most patients were in the 46–65 years age group (115, 48.5%). Males numbered 161 (67.9%), and females 76 (32.1%), with a male-to-female ratio of 2.1:1. The median duration of symptoms was 3 months (range 1 day to 30 years), with an IQR of 11 months. The most common symptom at presentation was a sudden decline in vision, reported by 100 patients (42.2%). Other frequent symptoms included poor vision in 36 patients (15.2%), progressive loss of vision in 36 patients (15.2%) and blurry vision in 27 patients (11.4%). Additionally, 8 patients (3.4%) experienced a veil-like covering sensation, 10 patients (4.2%) reported reduced vision, 9 patients (3.8%) experienced loss of vision, 5 patients (2.1%) had floaters and flashes of light, 3 patients (1.3%) reported cloudy vision and 1 patient (0.4%) complained of an eyeball misalignment, difficulty reading with glasses and an inferior visual field defect.
Types and prevalence of RD
Out of 237 RD patients (264 eyes), 167 (70.5%) were diagnosed with RRD, 61 (25.7%) with TRD, and 9 (3.8%) with ERD. Therefore, the hospital-based prevalence of all RD is 6.6 per 1000 patients (0.66%), and for RRD, it is 4.7 per 1000 patients (0.47%). The right eyes numbered 104 (39.4%), the left eyes numbered 106 (40.1%), and the bilateral cases numbered 54 (20.5%), involving 27 patients (11.4%). The distribution of RD eyes was 174 RRD eyes (65.9%), 80 TRD eyes (30.3%) and 10 ERD eyes (3.8%).
Descriptives and distribution of RD types
Table 1 offers a descriptive overview of the demographic and clinical features of three types of RD: RRD, TRD and ERD. To summarise the findings, RRD typically involves younger patients, has shorter symptom duration, a higher prevalence of myopia and is associated with previous eye trauma and intraocular surgeries, including cataract procedures. TRD is generally associated with older age, longer symptom duration, more frequent occurrence in the fellow eye and a stronger connection to systemic diseases. ERD occurs in patients slightly older than RRD but younger than TRD, with a longer symptom duration than RRD but like TRD, and is also related to systemic disease. Notably, trauma, myopia and prior intraocular surgery were not significant factors in TRD and ERD.
Table 1. Summarises the descriptives of three types of RD (RRD vs TRD vs ERD).
| Variables | n=174 | n=80 | n=10 |
|---|---|---|---|
| RRD | TRD | ERD | |
| Age (years) (mean (SD)) | 44.0 (17.5) | 52.3 (12.7) | 45.2 (20.4) |
| Age (years) categories n (%) | |||
| <25 years | 27 (15.5) | 4 (5.0) | 1 (10.0) |
| 26–45 years | 59 (33.9) | 11 (13.8) | 4 (40.0) |
| 46–65 years | 71 (40.8) | 55 (68.8) | 4 (40.0) |
| >66 years | 17 (9.8) | 10 (12.5) | 1 (10.0) |
| Duration of symptoms (months) (median (IQR)) | 2 (11.3) | 7.5 (31) | 7.5 (6.3) |
| Gender n (%) | |||
| Male | 122 (70.1) | 48 (60.0) | 7 (70.0) |
| Female | 52 (29.9) | 32 (40.0) | 3 (30.0) |
| Myopia n (%) | 48 (27.6) | 6 (7.5) | 0 (0.0) |
| Previous intraocular surgery n (%) | 41 (23.6) | 11 (13.8) | 1 (10.0) |
| Previous lens-related surgery n (%) | |||
| Cataract surgery | 17 (9.8) | 3 (3.8) | 0 (0.0) |
| Couching | 13 (7.5) | 2 (2.5) | 1 (10.0) |
| Previous eye trauma n (%) | 51 (29.3) | 6 (7.5) | 1 (10.0) |
| Family history of RRD* n (%) | 5 (2.9) | 1 (1.3) | 0 (0.0) |
| Fellow eye RD n (%) | 19 (10.9) | 32 (40.0) | 2 (20.0) |
| Systemic disease n (%) | 51 (29.3) | 71 (88.8) | 6 (60.0) |
| Lens status† n (%) | |||
| Aphakic | 12 (6.9) | 0 (0.0) | 1 (10.0) |
| Pseudophakic | 18 (10.3) | 3 (3.8) | 0 (0.0) |
| Phakic | 143 (82.2) | 77 (96.3) | 9 (90.0) |
Unavailable data in RRD (three eyes) and TRD (two eyes).
Unavailable data in RRD (one eye).
ERD, exudative RD; RD, retinal detachment; RRD, rhegmatogenous RD; TRD, tractional RD.
A detailed comparison of the three RD types shows that eyes with RRD were, on average, younger (44.0±17.5 years) compared with TRD patients (52.3±12.7 years), as shown in online supplemental figures 1 and 2. ERD patients had a mean age of 45.2±20.4 years. RRD was more common in the younger age group: 86 eyes (49.4%) were under 45 years. TRD patients were older, with the majority falling within the 46–65 years age range (68.8%), as shown in online supplemental figure 3. The median duration of symptoms for RRD was significantly shorter at 2 months, compared with 7.5 months for both TRD and ERD. Males comprised the majority of cases in all RD types: RRD (70.1%), TRD (60.0%), and ERD (70.0%). Myopia was notably more frequent in RRD patients (27.6%) than in TRD (7.5%) and was absent in ERD (0.0%), indicating a strong association between myopia and RRD. RRD eyes also showed the highest rate of previous intraocular surgery (23.6%), followed by TRD (13.8%), and ERD (10.0%). Among the 264 eyes assessed, 86.4% had no history of surgery, 7.6% had undergone cataract surgery, and 6.1% had undergone other ocular surgeries (online supplemental figure 4). Previous eye trauma was more frequent in RRD (29.3%) compared with TRD (7.5%) and ERD (10.0%). Family history of RD was rare: RRD (2.9%), TRD (1.3%) and absent in ERD. A history of fellow eye RD was more common in TRD (40.0%) than RRD (10.9%) and ERD (20.0%). Systemic disease was significantly more prevalent in TRD (88.8%) and ERD (60.0%) than RRD (29.3%), suggesting a stronger association between systemic health and TRD. Most eyes in all RD types were phakic, especially TRD (96.3%). Aphakia was more frequent in RRD (6.9%) and ERD (10.0%) but not present in TRD. Pseudophakia was observed more in RRD (10.3%) compared with TRD (3.8%) and was absent in ERD.
Analysis of eyes presenting with blinding RD (BCVA <3/60)
Out of the total eyes studied, 178 RD eyes (67.4%) had vision worse than 3/60 at presentation (legal blindness was defined as Snellen BCVA less than 3/60). Conversely, 86 eyes (32.6%) had Snellen acuity of 3/60 or better. Table 2 summarises the relationship between various demographic and clinical factors and vision worse than 3/60.
Table 2. Relationship between demographics, clinical characteristics in blind versus non-blind eyes.
| Variables | n=178 | n=86 | P value* |
|---|---|---|---|
| Blind eyes | Non-blind eyes | ||
| Age (years) (mean (SD)) | 47.6 (16.6) | 44.4 (16.8) | 0.14† |
| Age (years) categories n (%) | |||
| <25 years | 22 (12.4) | 10 (11.6) | 0.47 |
| 26–45 years | 46 (28.8) | 28 (32.6) | |
| 46–65 years | 88 (49.4) | 42 (48.8) | |
| >66 years | 22 (12.4) | 6 (7.0) | |
| Duration of symptoms (months) (median (IQR)) | 4 (11.5) | 2 (8.5) | 0.03‡ |
| Duration of symptoms (grouped) n (%) | 0.23 | ||
| <1 week | 13 (7.3) | 9 (10.5) | |
| 1 week to <1 month | 41 (23.0) | 28 (32.6) | |
| 1 to <3 months | 31 (17.4) | 15 (17.4) | |
| 3 to <6 months | 19 (10.7) | 10 (11.6) | |
| >6 months | 74 (41.6) | 24 (27.9) | |
| Gender n (%) | 0.64 | ||
| Male | 121 (68.0) | 56 (65.1) | |
| Female | 57 (32) | 30 (34.9) | |
| Presence of myopia n (%) | 26 (14.6) | 28 (32.6) | 0.001 |
| Previous intraocular surgery n (%) | 42 (23.6) | 11 (12.8) | 0.04 |
| Presence of systemic disease n (%) | 89 (50.0) | 39 (45.3) | 0.48 |
| RD type n (%) | 0.98 | ||
| RRD | 117 (65.7) | 57 (66.3) | |
| TRD | 54 (30.3) | 26 (30.2) | |
| ERD | 7 (3.9) | 3 (3.5) | |
| Previous eye trauma n (%) | 44 (24.7) | 14 (16.3) | 0.12 |
| Family history of RD n (%) | 2 (1.1) | 4 (4.7) | 0.17 |
| Fellow eye RD n (%) | 37 (20.8) | 16 (18.6) | 0.68 |
| Lens status† n (%) | 0.37 | ||
| Aphakic | 10 (5.6) | 3 (3.5) | |
| Pseudophakic | 17 (9.6) | 4 (4.7) | |
| Phakic | 150 (84.3) | 79 (91.9) | |
| Involved quadrants n (%) | <0.001 | ||
| 1 | 6 (4.3) | 8 (11.1) | |
| 2 | 26 (18.4) | 41 (56.9) | |
| 3 | 29 (20.6) | 14 (19.4) | |
| 4 | 80 (56.7) | 9 (12.5) | |
| Macular involvement n (%) | 172 (96.6) | 53 (61.6) | <0.001 |
| Extent of detachment n (%) | <0.001§ | ||
| Subtotal | 49 (43.8) | 52 (92.9) | |
| Total | 63 (56.3) | 4 (7.1) | |
| Presence of PVR n (%) | 49 (27.5) | 9 (10.5) | <0.001 |
| PVR grade n (%)¶ | 0.004 | ||
| A | 2 (1.1) | – | |
| B | 3 (1.7) | 3 (3.5) | |
| C | 17 (9.6) | 5 (5.8) | |
| D | 27 (15.2) | 1 (1.2) | |
| Presence of macular hole n (%) | 1 (0.6) | 1 (1.2) | 0.47 |
Pearson χ2.
Independent t-test.
Mann-Whitney U test.
Fisher’s exact test.
129 blind eyes and 77 non-blind eyes were excluded because they were non-PVR eyes.
ERD, exudative RD; PVR, proliferative vitreoretinopathy; RD, retinal detachment; RRD, rhegmatogenous RD; TRD, tractional RD.
Factors significantly associated with vision <3/60 at presentation (p<0.05)
The median duration of symptoms was notably longer in eyes with vision less than 3/60 (p=0.03, Mann-Whitney U), as shown in table 2. Moreover, a symptom duration exceeding 6 months was more frequently observed in eyes with <3/60 (41.6%) compared with 27.9% in eyes with better vision. Conversely, shorter symptom durations (≤1 month) were more common in non-blind eyes. These results suggest that a prolonged period before seeking treatment is strongly associated with the development of blind RD. Among eyes that were blind, 23.6% had a history of prior intraocular surgery, compared with 12.8% in non-blind eyes (p=0.004). Interestingly, 14.6% of blind eyes were myopic, compared with 32.6% of non-blind eyes (p=0.001), suggesting that myopia may offer some protection against blindness. Generally, a larger extent of RD significantly increases the risk of blindness; 56.7% of blind eyes involved all four quadrants of the retina, while only 12.5% of non-blind eyes did. Conversely, 56.9% of non-blind RD eyes involved two quadrants compared with 18.4% of blind eyes (p<0.001). The link between macular detachment and blindness was also statistically significant (p<0.001), with 96.6% of blind eyes having macula-off RD. Additionally, 56.3% of blind eyes had total RD, versus only 7.1% of non-blind eyes (p<0.001). Proliferative vitreoretinopathy (PVR) was observed in 27.5% of blind eyes compared with 10.5% of non-blind eyes, and this difference was significantly associated with blindness (p<0.001). Among the blind eyes, 15.2% had a Grade D PVR and 9.6% had a Grade C PVR. In contrast, only 1.2% of non-blind eyes had grade D and 5.8% had grade C, indicating a strong link between severe PVR grades and blindness, with the most advanced grades predominantly found in blind eyes (p=0.004).
Logistic regression of the effect of independent variables on presenting vision <3/60 in all RD eyes
The initial model employed univariate and multivariate regression analysis on all RD eyes to assess whether factors including age, symptom duration, gender, prior intraocular surgery, eye trauma, myopia, family history of RD, RD quadrants and RD extent could predict blindness. Findings are represented in table 3.
Table 3. Univariate and multivariate logistic regression for all RD eyes.
| Variable Univariate | B | OR (Exp(B)) | 95% CI | P value |
|---|---|---|---|---|
| Age | 0.01 | 1.001 | 0.996 to 1.027 | 0.14 |
| Duration of symptoms (continuous) | 0.01 | 1.01 | 0.997 to 1.026 | 0.13 |
| Duration of symptoms >6 months | 0.76 | 2.14 | 0.812 to 5.612 | 0.12 |
| Male gender | 0.13 | 1.14 | 0.660 to 1.959 | 0.64 |
| Previous ocular surgery | 0.75 | 2.11 | 1.024 to 4.331 | 0.04 |
| Previous eye trauma | 0.53 | 1.69 | 0.867 to 3.287 | 0.12 |
| Family history of RD | −1.45 | 0.24 | 0.042 to 1.312 | 0.10 |
| Fellow eye RD | 0.14 | 1.15 | 0.598 to 2.205 | 0.68 |
| Presence of myopia | −1.04 | 0.35 | 0.192 to 0.654 | 0.001 |
| Pseudophakia | 0.81 | 2.24 | 0.728 to 6.879 | 0.16 |
| Aphakia | 0.56 | 1.76 | 0.470 to 6.563 | 0.40 |
| Total RD | 2.82 | 16.71 | 5.657 to 49.383 | <0.001 |
| >3 quadrants involved | 2.47 | 11.85 | 3.352 to 41.910 | <0.001 |
| Macula-off RD | 2.88 | 17.84 | 7.094 to 44.912 | <0.001 |
| Multivariate | ||||
| Total RD | 2.11 | 8.24 | 1.92 to 35.43 | 0.005 |
| Macula-off | 2.49 | 12.11 | 2.65 to 55.40 | 0.001 |
| Age | 0.03 | 1.033 | 1.002 to 1.065 | 0.04 |
RD, retinal detachment.
Univariate analysis identified previous intraocular surgery as a significant predictor of blindness (p=0.04). Eyes with such a history had 2.1 times higher odds of being blind at presentation (β=0.745, OR=2.106, 95% CI: 1.024 to 4.331, p=0.04). Interestingly, there was an inverse relationship between a history of myopia and blindness; individuals with a history of myopia had significantly lower odds of blindness at presentation (β=−1.038, OR=0.354, 95% CI: 0.192 to 0.654, p=0.001). The extent of RD was another key predictor. Total RD increased the odds of blindness more than 16-fold (β=2.816, OR=16.714, 95% CI: 5.657 to 49.383, p<0.001). Greater quadrant involvement was associated with increased risk of blindness (p<0.001), with detachment in more than three quadrants raising the odds to 11.85 times that of a single-quadrant detachment (β=2.472, OR=11.85, 95% CI: 3.35 to 41.91, p<0.001). The status of the macula was also significant; eyes with macula-off detachment had 17.9 times higher odds of blindness at presentation compared with macula-on eyes (β=2.882, OR=17.85, 95% CI: 7.09 to 44.91, p<0.001).
In the final multivariate logistic regression model, increasing age, total RD and macula-off status were independently linked to a higher probability of blindness at presentation (table 3). Age appears to be the most significant factor to notice. In the univariate model, the association with age is weak and has a relatively wide CI. After adjusting for other factors, the coefficient becomes approximately three times larger, and the CI no longer includes the null value. This change is likely because accounting for confounding factors clarified the effect of age. Specifically, each additional year of age increased the odds of presenting with blindness by 3.3% (β=0.032, OR=1.0, 95% CI=1.002 to 1.065, p=0.04). Eyes with macula-off detachments had 12 times higher odds of blindness (β=2.494, OR=12.1, 95% CI: 2.65 to 55.40, p=0.001), whereas those with total RRD had 8.2 times increased odds (β=2.109, OR=8.2, 95% CI: 1.92 to 35.43, p=0.005), compared with eyes without these conditions.
Treatment, reasons for non-treatment and treatment outcome
Because we included a retrospective review of outcomes in this study, we were able to determine the treatment outcomes. Table 4 outlines treatments for RD. Surgery was the most frequent treatment approach, vitrectomy alone performed in 52.7% eyes, combined phacoemulsification and vitrectomy in 8.7%, and scleral buckling in 4.5% of eyes. Fewer eyes received laser therapy (2.7%), medical treatment (0.8%) or intravitreal Avastin injections (0.8%). Notably, 11.0% of patients were advised against treatment, and 8.7% received no treatment because of advanced disease or were lost to follow-up. Additionally, 9.8% were referred to other eye hospitals because of resource limitations or a lack of surgical equipment for treating RD.
Table 4. Treatment options and non-treatment of all retinal detachment eyes.
| Treatment | Frequency (n) | Percentage (%) |
|---|---|---|
| Surgical treatment for RD | ||
| Vitrectomy | 139 | 52.7 |
| Phacoemulsification+vitrectomy | 23 | 8.7 |
| Scleral buckle | 12 | 4.5 |
| Non-surgical treatment for RD | ||
| Retinal laser | 7 | 2.7 |
| Medical treatment | 2 | 0.8 |
| Intravitreal Avastin | 2 | 0.8 |
| Others | ||
| Evisceration | 1 | 0.4 |
| No treatment advised | 29 | 11.0 |
| No treatment given or lost to follow-up | 23 | 8.7 |
| Referred to other centres | 26 | 9.8 |
RD, retinal detachment.
Furthermore, during our cross-sectional study, 92 eyes (34.8%) had not undergone any treatment. The primary reasons included a lack of equipment (41.3%) and the inability to afford the costs (40.2%). Others were due to poor prognosis (16.3%) and waiting for specialist review (2.2%).
As shown in table 5, shorter symptom duration correlates with better preoperative mean Log MAR vision compared with longer durations, and this difference was significant (p=0.001). This difference is also reflected in the degree of improvement in postoperative mean vision (p=0.02). Additionally, the preoperative proportion of blind eyes (<3/60) decreased compared with postoperative values after surgery across all five symptom duration categories, indicating the positive effect of surgery on vision. Even eyes with longer symptom durations, >6 months, showed a postoperative reduction in blindness. Nevertheless, postoperative blindness rates were significantly lower in the <1 week group (27.3%) compared with the >6 month group (41.2%) (table 6), indicating that a shorter duration is beneficial for better postoperative outcomes. The average follow-up time for all eyes was 16.3 months, and no statistically significant difference was found between the five symptom duration groups (p>0.05).
Table 5. Symptom duration categorisation against preoperative and postoperative vision and rates of ‘blind’ and ‘not blind’.
| Symptom duration | Preoperative VA (mean LogMAR vision) | Preoperative Snellen VA | Postoperative VA (mean LogMAR vision) | Postoperative Snellen VA | ||
|---|---|---|---|---|---|---|
| Blind n (%) | Not blind n (%) | Blind n (%) | Not blind n (%) | |||
| <1 week | 1.547 | 13 (59.1) | 9 (40.9) | 0.893 | 3 (27.3) | 8 (72.7) |
| 1 week to <1 month | 2.021 | 41 (59.4) | 28 (40.6) | 1.29 | 18 (52.9) | 16 (47.1) |
| 1 to <3 months | 1.883 | 31 (67.4) | 15 (32.6) | 1.15 | 5 (35.7) | 9 (64.3) |
| 3 to <6 months | 2.19 | 19 (65.5) | 10 (34.5) | 1.63 | 3 (42.9) | 4 (57.1) |
| >6 months | 2.692 | 74 (75.5) | 24 (24.5) | 2.32 | 21 (41.2) | 30 (58.8) |
| Significance (p value) | 0.001* | 0.017* | ||||
Mean LogMAR vision represents the average Snellen vision of eyes within each symptom duration category, converted to LogMAR units.
Kruskal Wallis p<0.05.
LogMar, logarithm of the minimum angle of resolution; VA, visual acuity.
Table 6. Change in vision of surgically treated RD eyes.
| Variable | Better n (%) | Same n (%) | Worse n (%) |
|---|---|---|---|
| 1 month n=124 eyes | 54 (43.5) | 31 (25.0) | 39 (31.5) |
| 12 months n=98 eyes | 61 (62.2) | 5 (5.1) | 32 (32.7) |
RD, retinal detachment.
Postoperative outcome
Data on treatment outcomes were available for 209 eyes, of which 169 (80.9%) had surgery. Before surgery, 117 of these 169 eyes (69.2%) were blind. Visual results were assessed at 1 month and 12 months postsurgery. Furthermore, postoperative vision was classified as improved, unchanged or worse relative to presurgery vision.
At the 1-month follow-up, 124 out of 169 surgical eyes (82.7%) had follow-up. Of these, 68/124 eyes (54.8%) remained blind after surgery. At 12 months, 98 of 169 eyes (58.0%) had follow-up. Among these, 39/98 eyes (39.8%) remained blind. Therefore, the proportion of blind eyes at twelve months was noticed to progressively decrease from the value at 1 month.
At the 1-month follow-up, 54 of 124 eyes (43.5%) showed improved vision, while 31 eyes (25%) exhibited no change from baseline, and 39 eyes (31.5%) experienced deterioration. By 12 months, 61 of 98 eyes (62.2%) had improved vision, 5 eyes (5.1%) remained unchanged and 32 eyes (32.7%) worsened compared with baseline, as shown in table 6 and online supplemental figure 5, which compares the rate of improved vision between months 1 and 12.
Earlier presentation (<1 week) was associated with the lowest postoperative blindness rates at months 1 and 12. In contrast, longer symptom duration, particularly beyond 3 months, was associated with higher rates of postoperative blindness at months 1 and 12 (online supplemental figure 6).
Eyes presenting within 1 week and between 1 and 3 months had significantly lower odds of blindness at 1 month compared with those presenting after 6 months. Eyes presenting within 1 week had 78% lower odds (β=−1.514, OR=0.22, 95% CI=0.062 to 0.784, p=0.02) of blindness compared with those presenting after 6 months. Eyes presenting between 1 and 3 months had 69% lower odds (β=−1.517, OR=0.31, 95% CI=0.114 to 0.865, p=0.03) of blindness compared with those presenting after 6 months.
Discussion
Nigeria is the most populous country in Africa,12 with over 200 million people. RD is the most common reason for vitreoretinal surgery and a leading cause of blindness among Nigerians and Africans. Fortunately, surgery often yields successful outcomes even when patients present late, resulting in notable improvements in vision. As a result, treating RRD can be highly effective and can reverse blindness. Addressing RRD presents a valuable chance to decrease blindness rates across Nigeria and the wider African region. However, associations of RD in Nigerians and Africans have not been studied in detail, despite previous research in Caucasians and Asians being extrapolated to Africans without direct evidence. Therefore, we conducted a multicentre study to evaluate the associations of RD and factors linked to blind RD at presentation. The findings from this study, based on research conducted in Nigeria, lay the groundwork for public awareness and intervention programmes aimed at improving clinical presentation and outcomes for RD. These findings will also help in planning larger, nationwide surveys and interventions for RRD and other forms of RD. These research findings could be cautiously extrapolated to other African states.
This study is the first prospective, multicentre research on RD in Nigeria with the largest sample size to date. It focused on RD among Nigerians, analysing demographics and clinical features. We found that 67.4% of patients presented with blinding RD and identified associated risk factors. The 71% rate of blinding RD reported by Nkanga et al is similar to the rates in our study, indicating that significant progress is still needed to improve RD-related presenting vision and visual outcomes in Nigerians. Retrospectively, we evaluated surgical results and their relation to the time to presentation. Our data support findings from studies outside Africa, which show that shorter symptom durations are associated with better visual acuity at presentation and improved preoperative and postoperative vision compared with longer durations (see table 6). Additionally, vitreoretinal surgery reduced blindness rates across all symptom duration groups, regardless of the initial vision, demonstrating its effectiveness in reversing blindness related to RD.
Since Yorston et al’s publication over two decades ago on RD in East Africa,4 subsequent studies have also reported delayed and complicated presentations of RRD in African patients. This pattern seems unique to RRD in Africa and other LMICs, where limited healthcare access results in more severe vision loss in eyes diagnosed to have RD. Risk factors and associations for RRD have been well-documented in other regions of the world. For instance, the association of RRD with previous cataract surgery, trauma and link with family history was reported over a decade ago by the Scottish Retinal Detachment study.13
Epidemiological studies to determine the exact frequency and associations for RRD and other types of RD have not been done in Nigerians. The current study, though hospital-based, is the first attempt to determine associations for RD and, at the same time, investigate the risk for blind RD at presentation in Nigerians. This was a non-interventional study; however, we retrospectively reviewed the records of participants and researched the surgical visual outcome. Presenting vision of RRD and postoperative outcome after surgical repair in Africans has been reported by previous researchers who have shown that though presenting vision is poor, vision does improve in several instances. We examined the rate of blindness in the three types of RD and found this to be high. Overall, in the entire RD cohort, greater than two-thirds of eyes were blind at presentation; individually, RRD 117 (67.2%), TRD 54 (67.5%) and ERD 7 (70%) eyes were blind.
We found that the risk factors for blind RRD presentation included longer symptom duration, prior ocular surgery (especially cataract surgery), extent of RD, the number of quadrants involved by RD, macular off status, presence of advanced grade of PVR and lattice degeneration. Limited access to eye and retina care due to patient-related factors (such as poor knowledge or awareness of eye care, financial difficulties and the inability to afford services) and infrastructure and personnel-related issues (like unavailability of ophthalmic care, technology and trained retina specialists) leads to delays in patients seeking care and receiving treatment. These delays result in more severe RDs, macular-involving RDs and sometimes PVR or macular holes at presentation, all of which negatively affect treatment outcomes. Therefore, as observed by other researchers and confirmed in this study, reducing the duration of symptoms before presentation is essential for Nigerian RD patients. Efforts should, therefore, focus on improving access to eye and retina care.4 5
In this study, eyes that had previous ocular surgery, especially cataract surgery, were at risk of blind RRD. There is a trend towards increasing cataract surgical rates in Nigeria and across Africa, as a way of addressing cataract blindness. This may increase the RRD rate, as experienced in some developed countries. Myopia was more associated with RRD (28%) compared with TRD (8%). A recent report indicates an increase in myopia among Nigerian children. Additionally, 1 in 20 African school children is myopic.14 This points to a growing role of myopia in RD across Africa. Myopia intervention is needed in Nigeria and Africa as elsewhere in the world.
According to our search, this study provides the most comprehensive data on associations of RRD in Nigerians. RRD had the highest proportion of eyes. Of 264 eyes, there were 65.9% RRD, 30.3% TRD and 3.8% ERD. RRD contributed two-thirds of the RD cases, and TRD close to one-third. RRD is known to be the most common form of RD in other regions of the world, and our finding confirms this to be the same in Nigerians. The estimated prevalence of RRD in this study, 4.7 per 1000 patients is likely overestimated and will be lower in population studies. But this is the first attempt at establishing RRD prevalence in Nigeria, providing a foundation for future prevalence studies.
Shahid et al from Pakistan report that young age <45 years accounted for most RRD cases.15 The mean age for RRD patients in this study, 44.0±17.5 years, is lower than the 48 years reported from both Ibadan, Nigeria and Accra, Ghana.5 16 In Kenya, the average age was 47 years.4 In a more recent population-based 5-year longitudinal study from Mainz, Germany, mean age was much higher, 55 years.17 In the USA, an older study reported mean age at diagnosis of RRD was 50 years for men and 59 years for women.18 The younger age of African RRD patients compared with Europeans and American populations has also been noted by Yorston et al, but the reasons for this remain a matter of speculation.
Another finding in this study is male dominance. Males were more affected across all types of RD. Generally, there were about two affected males for every female, with male rates of 70.1% for RRD, 62.3% for TRD and 66.7% for ERD. The predominance of male RRD has been a consistent finding in other reports, both within and outside Nigeria and Africa. In our study, RRD had a higher M:F ratio of 2.3:1, compared with 1.7:1 for TRD and 2:1 for ERD. The RRD ratio in this study is similar to Ghana’s 2.5:1.16 There was a notable difference between two Nigerian studies, with ratios of 1.6:1 (Ibadan)5 and 3.7:1 (Kaduna).10 These differences could be due to ethnic or geographic factors influencing Nigerians. A report from India also mirrors our findings with a ratio of 2.4:1.19 Scottish data from a population-based study reports 1.7:1,20 the USA has a ratio of 1.7:1,18 and in Germany, the ratio is 1:1.17 Perhaps the lower M:F ratios in developed countries in Europe and America reflect greater access for females to population studies, considering that the three studies from Europe and the USA were population-based, while our study and other African studies were hospital-based. Accessibility to hospitals and related factors is likely a significant influence. We also found that, consistent with other studies, male gender carried a higher risk of RRD. Conversely, female gender was associated with a higher risk of TRD. The observation that females had a higher risk of presenting with blind RRD, and males with blind TRD, provides important gender-based information that was previously unknown in Nigeria. These differences could be related to poor access and delays in diagnosis of RRD, diabetes and TRD.
Bilateral RRD is a serious concern and carries the risk of bilateral blindness. The rate of bilateral RD in the entire series (ie, patients presenting with bilateral RD) was 11.4%. This is lower than the 17.5% reported from Ethiopia. Keep in mind that both studies include RRD and TRD. In our study, TRD had the highest rate of bilateral cases, at 31%. Systemic diseases, including diabetes mellitus, affect both eyes, and PDR is the most common cause of TRD, as we previously reported.7 Patients with bilateral RRD in this study accounted for 4.2% (8% of eyes). In Kenya, the rate was higher, with 43 out of 345 patients (12.5%) having bilateral RD. The Scottish RD study reported a bilateral RD rate of 7.3%, noting that fellow eye RD was more common in pseudophakic and myopic patients.21 In Germany, no cases of bilateral RD were observed over 5 years of surveillance in Mainz.17 Another study from Regensburg, Germany, reported a 10.4% rate of bilateral RD in eyes.22 Singh et al23 studied the characteristics and outcomes of surgery in 168 bilateral eyes (84 patients). They noted a young age, association with myopia and the occurrence of the same type of retinal break in both eyes. To conclude, the rate of bilateral RD varies widely in the literature, and our rate is probably among the lowest reported. Young age, pseudophakia and myopia are potential risk factors.
Though the symptom duration before presentation in our study was undesirably long, RRD patients in this study presented on average earlier than TRD and ERD; 2 months compared with 7.5 months. This could be because RRD is associated with an acute occurrence of PVD, which manifests significant symptoms, unlike TRD and ERD, which have a chronic, slower onset and progression. The predominant patient’s symptom was a sudden decline in vision. Seeing flashes of light and floaters, typical for PVD, occurred in a minority of patients. Therefore, several RRD patients may not volunteer symptoms of acute PVD, including flashes and floaters, at presentation. Duration before clinic presentation is a significant issue highlighted by previous research on RRD. However, the 2 months recorded in this research is the lowest duration reported, compared with other Nigerian and African studies, including 7.5 months (Kaduna), 3 months (Ibadan), 5 months (Accra), and 13.5 months (Lagos). It could be that efforts at increasing awareness and access to eye care are yielding results in Nigeria. From India comes a 1.8-month report of mean symptom duration.19 Efforts should be focused on reducing duration further to less than a week or days of symptom onset and reducing the rate of macular involving RRD, which in this report and others from Nigeria is close to or exceeds 90%.
This study revealed a high rate of blinding RD in Nigerians, and a major finding is the relationship between duration of symptoms at presentation and blinding RD. Eyes that had less than 1 week of symptoms were significantly associated with less blindness than eyes with >6 months of symptoms. Table 5 shows a statistically significant progressive decline in presenting preoperative mean logarithm of the minimum angle of resolution (LogMAR) vision with increasing duration of symptoms, which corresponds to a similar decrease in postoperative mean LogMAR vision. The unacceptably high rate of blinding RD, according to this study, is significantly influenced by disease duration before presentation. Other significant risks of blindness revealed by this research include the extent of RD, macular involvement and PVR, which can be related to the longer duration of disease. The importance of early presentation and rapid treatment of RD is clearly illustrated by the lower rates of preoperative and postoperative blindness seen in eyes that present for treatment within 1 week of symptom onset. Blindness rates at 12 months of follow-up are significantly lower when eyes are treated within a week. 1 week or less should, therefore, be the logical target for treating all Nigerian RD eyes (online supplemental figure 6). Another significant finding of this study is the reduced rate of blindness when comparing preoperative to postoperative vision following vitreoretinal surgery. Our data clearly show that despite weeks of delay, surgical treatment improves the vision in several RD eyes (online supplemental figure 6). These data substantiate previous findings that, despite delayed and complex RD presentations, surgery can be beneficial in curing RD-related blindness. Therefore, access to RD surgical intervention should be listed and prioritised by governments, policy-makers and health authorities as a blindness reversal strategy in Nigerians and Africans.2 4 Vitreoretinal surgery should be prioritised as a vision restoring and blindness preventing intervention.
Our study has limitations, including the absence of long-term follow-up of patients and eyes. As a result, the progression of some RD cases and the monitoring of fellow eyes were not captured. As a result, the entire impact of the assessed variables may not be known. As a hospital-based investigation, it likely overestimates the incidence and rates of RD compared with population-based studies, which tend to provide a more accurate estimate of RD prevalence among Nigerians. Future research should also account for Nigeria’s geographic diversity, since RD may be more prevalent in certain ethnic groups—an aspect this study cannot identify. Furthermore, some data relied on participant self-reporting, such as symptom duration and medical and family histories, which makes the findings vulnerable to patient bias and recall errors. The retrospective component of this study, which considered the surgical visual outcome, gave useful insight into the impact of symptom duration on visual outcome. This adds both weakness and strength to our study. The weakness is due to missing data and the fact that some patients failed to keep their scheduled clinic appointments. However, the 1-month postoperative follow-up rate was 83% and the 12-month rate was 58%. On the other hand, this report of a visual outcome correlating with symptom duration is considered unique to our study and has not been previously reported in any other African RD study. Therefore, this is a strength for our study as it provides useful firsthand information on the impact of symptom duration on surgical outcome, thus providing useful data for advocacy to patients, governments and other stakeholders.
There are improvements that can be made in future studies. For instance, the dioptric quantification of myopia and the axial length of the eyes were not measured to quantify the degree of myopia. Future studies should better characterise the types and numbers of retinal breaks, the occurrence of posterior vitreous detachment and the exact timing of cataract surgery to give an estimate of the time from cataract surgery to developing RRD. Also, Nigeria is a multiethnic country; the incidence of RRD in Nigerians in general and within the diverse ethnicities should be researched to determine if there are ethnic differences in RRD. As attention shifts to posterior segment causes of blindness in Nigerians and Africans, RD and specifically RRD will take centre stage, being a reversible cause of blindness. This research gives a two-thirds estimate of blindness in RD eyes and characterises the local associations and risk factors for RD-related blindness at presentation. The findings of this research will aid in the screening and early diagnosis of RRD and other forms of RD. This will ultimately lead to improved treatment outcomes. The younger age of African RRD patients compared with Caucasians deserves further investigation. This study sets the stage for a Nigerian Retinal Detachment Study, a prospective, population-based, longitudinal study that will determine the true incidence of RRD, examine ethnic differences and ultimately lead to improved outcomes of RRD surgery.
Supplementary material
Footnotes
Funding: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Prepublication history and additional supplemental material for this paper are available online. To view these files, please visit the journal online (https://doi.org/10.1136/bmjopen-2024-098073).
Provenance and peer review: Not commissioned; externally peer reviewed.
Patient consent for publication: Not applicable.
Ethics approval: This study involves human participants. The study adhered to the principles of the Declaration of Helsinki and received ethical approval from the Eye Foundation Hospital’s Health Research Ethics Committee (Reference Number: EFH-HREC/2019/03), which also covered the other study sites. Participants gave written informed consent and could decline the examination without any negative impact on their eye care. Participants gave informed consent to participate in the study before taking part.
Collaborators: Collaborative Retina Research Network (CRRN): Ogugua Ndubuisi Okonkwo, Idris Oyekunle, Olukorede Adenuga, Dennis Nkanga, Wilson Ovienria, Chineze Agweye, Toyin Akanbi, Affiong Ibanga, Martha Mary Udoh.
Patient and public involvement: Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Data availability free text: The data are available from Becky Agbaje, secretary of the Eye Foundation Ethics Committee, who can be reached via email at becky.agbaje@eyefoundationhospital.com or bioethics@eyefoundationhospital.com.
Data availability statement
Data are available on reasonable request.
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