Clinical presentation and visual status of retinitis pigmentosa patients: a multicenter study in southwestern Nigeria

First Insights Into the Phenotype and Genotype of Inherited Retinal Disorders in the Democratic Republic of Congo (DRC)

PURPOSE/INTRODUCTION

Inherited retinal disorders (IRD) are a highly heterogeneous group of retinal diseases often characterized by progressive bilateral degeneration of rod and cone photoreceptors. Very little information is available on the genotype and phenotype of IRD in Central Africa. We investigated genetic causes of IRD in a well-characterized group of patients from the Democratic Republic of Congo (DRC).

MATERIALS AND METHODS

Ten patients, from eight families, with a clinical diagnosis of IRD in Kinshasa (DRC) were investigated. Each patient underwent general, dysmorphological and ophthalmic examination. DNA was extracted in the Centre for Human Genetics of the University of Kinshasa and clinical Whole Genome Sequencing (cWGS) was performed at Illumina Clinical Service Laboratory through the Illumina iHope program.

RESULTS

The eight probands comprised 4 males and 4 females aged between 17.5 and 76 years. Nyctalopia and reduced visual acuity were the main complaints. All patients had normal hearing and were nondysmorphic. Fundus examination revealed bone-spicule pigment in all patients. Twelve plausible causal variants were identified in six genes: ADAM9, RP1, MERTK, CYP4V2, USH2A, and IFT140. One SNV and one intragenic CNV were novel. The SNV was assumed to be in trans with an intragenic SNV in three families, consistent with the well-known autosomal recessive inheritance for IRD in those genes.

CONCLUSION

We report on the first cohort of African IRD patients investigated by cWGS. Our results indicate that also in Congolese patients, the spectrum of causal genes is broad and we expand the spectrum of causal variants in known IRD genes. This report demonstrates the power of cWGS, especially for genetically heterogeneous diseases.

Clinical presentation and macular morphology in retinitis pigmentosa patients

Background

Optical coherence tomography (OCT) is a noninvasive, frequently used imaging technology that enables detailed viewing of retina anatomy. It is used to monitor disease progression in retinitis pigmentosa (RP) eyes, including detecting changes in retinal thickness.

Purpose

The purpose of the study is to determine the clinical presentation and macular morphology in RP eyes using OCT imaging.

Methods

A retrospective review of case records and OCT scans in eyes diagnosed with RP in two ophthalmic clinics in Nigeria. Biodata, Snellen best-corrected visual acuity (BCVA), intraocular pressure (IOP), vertical cup-to-disc ratio (VCDR), and presence of maculopathy were determined. Data were analyzed using IBM SPSS version 22.0 (IBM Corp. Armonk, NY, USA).

Results

Fifty-five eyes of 28 patients (18 males and 10 females), with a mean age of 47.16 ± 15.56 years (22-77 years), were studied. 40-49 years was the most frequent age group, 28.6%. Severe visual impairment occurred in 22% of eyes and myopia in 32%. Twenty-nine percent had undergone cataract surgery or had a significant cataract. The mean IOP was 11 mmHg, and the mean VCDR was 0.46. On OCT examination, macular atrophy was the most common finding in 74.5% of eyes, epiretinal membrane in 16.3%, cystoid macular edema in 7.3%, vitreomacular adhesion in 5.4%, and vitreomacular traction in 1.8%. There was no association between macular morphology, macular thickness, and BCVA (P = 0.155, P = 0.424).

Conclusion

OCT provides information on macula structure in RP eyes. About 14.5% of eyes had a normal macula, while 85.5% had a maculopathy, confirming that RP eyes have a higher rate of maculopathy than non RP eyes. OCT evaluation of an RP eye should be a standard workup for the early detection of such maculopathy and monitoring for disease progression.

Ocular abnormalities in a large patient cohort with retinitis pigmentosa in Western China

Background

To report the prevalence of ocular abnormalities and investigate visual acuity in a large cohort of retinitis pigmentosa (RP) patients in Western China.

Methods

The medical records and ophthalmic examination reports of 2127 eyes of 1065 RP patients at one eye hospital were retrospectively reviewed to determined the prevalence of ocular abnormalities and the relationship between best corrected visual acuity (BCVA) and macular abnormalities.

Results

Nyctalopia (58.2%) and blurred vision (27.1%) were the leading reasons for RP patients to request an ophthalmic examination. BCVA measurements in the better eyes at first clinical presentation showed that 304 patients (28.5%) were categorised as blind and 220 patients (20.7%) as low vision. The most common ocular abnormalities were macular abnormalities (59.7%) and cataracts (43.1%). The macular abnormalities included epiretinal membranes (51.1%), cystoid macular edema (18.4%), vitreomacular traction syndrome (2.4%), macular holes (2.3%) and choroidal neovascular membranes (0.05%). Glaucoma was found in 35 eyes (1.6%). The proportions of epiretinal membranes (p = 0.001) and macular holes (p = 0.008) increased significantly with age. Cystoid macular edema was significantly associated with poorer visual acuity in RP patients with clear lens (p = 0.002).

Conclusion

Cataracts and macular abnormalities are common in RP patients. Of the macular abnormalities, cystoid macular edema may have a negative effect on BCVA in RP patients with clear lens. Therefore, optical coherence tomography screening in RP patients is highly recommended for early detection and treatment of maculopathy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-020-01797-z.

Profile, Visual Presentation and Burden of Retinal Diseases Seen in Ophthalmic Clinics in Sub-Saharan Africa

Purpose

To determine the burden of retinal diseases and the degree of visual impairment associated with each disease, amongst Nigerians.

Patients and Methods

This was a hospital-based multicenter, prospective, cross-sectional, non-comparative study conducted from January to December 2018. Data was obtained from consecutive patients with a retinal diagnosis presenting at the general ophthalmic and specialty retina clinics in four hospitals (three public, and one private teaching eye department) in Nigeria. Biodata, visual acuity and refraction, intraocular pressure, findings on dilated retinal examination, diagnosis and systemic diseases were noted. Degree of monocular and bilateral visual loss associated with each diagnosed retinal disease was summarized and p value was calculated using chi-square test. P < 0.05 was considered significant.

Results

Eight hundred seventy-six of 8614 patients had a retinal diagnosis; establishing a hospital-based retinal disease prevalence of 9.8%. Male:female ratio was 1.1:1. The mean age of study patients was 49.97 (standard deviation 17.64 years). Mean symptom duration was 21.63 months (standard deviation 41.94). The mean intraocular pressure was 13.87 mmHg. Forty-three different retinal diseases were diagnosed. The most common was retinal complications of diabetes, i.e., diabetic retinopathy (DR) alone, diabetic macular edema (DME) alone and a combination of DR and DME, which accounted for 13.7%, 5.6% and 9.3%, respectively (contributed 28.6% of the entire diagnosis). This was followed by retinal detachment (RD), in 219 eyes (15.4%), dry age-related macular degeneration (AMD) in 124 eyes (8.7%). Nearly half of the eyes were blind or severely visually impaired. Blindness occurred in 34.1% of eyes; severe visual impairment in 8.2% of eyes and 29.7% had normal vision. There were 469 patients who had systemic diseases. The common systemic diseases were hypertension in 169 patients (19.3% of the total number of patients), hypertension and diabetes in 156 patients (18%), and diabetes alone in 98 patients (11.1%). Sickle cell disease was present in 1.5%.

Conclusion

There is need to invest in infrastructure, local training and development of systems for early detection and treatment of several retinal diseases in sub-Saharan Africa; DR and DME having the largest burden. Collaborative physician care and management of hypertension and diabetes could significantly reduce the burden of DR and DME.

Retinitis pigmentosa in Onitsha, Nigeria

Background:

Retinitis pigmentosa describes a heterogenous group of progressive hereditary degeneration of the photoreceptor-retinal pigment epithelium complex with varying clinical manifestations. Although studies on the epidemiology of blindness and visual impairment in Nigeria have documented the contribution of retinitis pigmentosa, detailed study of the prevalence, incidence, and pattern of retinitis pigmentosa in Nigeria are few.

Objectives:

The aim of this study was to describe the relative frequency rate and pattern of retinitis pigmentosa among new patients at the Guinness Eye Center Onitsha Nigeria.

Materials and Methods:

Case files of new patients with clinical features of retinitis pigmentosa seen over a 6-year period were reviewed. Information on age, sex, and associated clinical features were extracted into a standard proforma and analyzed.

Results:

Thirty-seven (0.6%) of 5876 new patients had retinitis pigmentosa. There were 25 (67.6%) males and 12 (32.4%) females with an age range of 4–76 years; the median age was 33 years. Family history suggested autosomal dominant inheritance in 15 (40.6%) patients, autosomal recessive inheritance 4 (10.8%), X-linked inheritance 9 (24.3%), and 9 (24.3%) sporadic. Six (16.2%) patients were blind (acuity <3/60) and 22 (59.5%) patients had visual impairment (acuity <6/18). Eight (21.6%) patients had coexistent deafness (syndromic retinitis pigmentosa) including two (5.4%) cases of Usher syndrome.

Conclusions:

The relative frequency rate of retinitis pigmentosa among new patients in our hospital is low but the associated visual and otologic incapacitation are enormous. A prospective study incorporating molecular genetics would more exactly determine the inheritance pattern and the common genes of retinitis pigmentosa in Nigerians.

Acute angle closure following periorbital botulinum toxin injection in a patient with retinitis pigmentosa

A 50-year-old female presented with bilateral retinitis pigmentosa (RP) and acute angle closure (AAC) with fixed mid-dilated pupil and high intraocular pressure (IOP) in the left eye following left side periorbital botulinum toxin A injection for blepharospasm. Glaucomatous optic neuropathy and retinal nerve fiber layer defect were observed in the affected eye using optical coherence tomography although the IOP was maintained at <21 mmHg after the treatment. Botulinum toxin acts at the cholinergic synapse and inhibits acetylcholine release; hence, it can cause transient mydriasis and may lead to AAC in high-risk populations such as patients with RP. Patients should be explained about the possible development of mydriasis associated with botulinum toxin injection, and clinicians must evaluate the level of risk for AAC before administration of botulinum toxin around the eyelid. In cases showing side effects associated with botulinum toxin injection, early diagnosis and treatment is required to prevent blindness.