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ORIGINAL ARTICLE
Year : 2020  |  Volume : 7  |  Issue : 1  |  Page : 11-15

Screening of retinitis pigmentosa among Sudanese students of Al-Neelain University Eye Hospital, Khartoum, Sudan


1 Department of Outpatient, Khartoum Eye Teaching Hospital, Khartoum, Sudan
2 Department of Ophthalmology, Faculty of Medicine, Al-Neelain University, Khartoum, Sudan

Date of Submission06-Jul-2020
Date of Acceptance16-Jul-2020
Date of Web Publication31-Dec-2020

Correspondence Address:
Prof. Mahgoub Saleem
Department of Ophthalmology, Faculty of Medicine, Al-Neelain University, Khartoum 11111, P.O. Box 10139
Sudan
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DOI: 10.4103/bijo.bijo_8_20

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  Abstract 


Background: Retinitis pigmentosa (RP) is a genetic retinal disorder that leads to progressive visual impairment. Early symptoms are night blindness, followed by the loss of peripheral vision and constricted visual fields. The symptoms and signs worsen as time goes.
Objectives: The objective of this study was to determine the incidence of RP among Sudanese students of Al-Neelain University College of Optometry and Visual Science from March to May 2017.
Materials and Methods: In a cross-sectional observational hospital-based study, which was conducted at Al-Neelain University Eye Hospital, Gabrah, Khartoum, Sudan, in 3-month period, from March to May 2017, by a consecutive sampling technique, 193 Sudanese students from Al-Neelain University College of Optometry and Visual Science were examined for the presence of RP. Data were statistically analyzed using SPSS.
Results: Females were 154 (79.8%) and males were 39 (20.2%). Their mean age was 21.76 years ± 2.5 years (range: 16–25 years). One hundred and forty-five (75.1%) students were between 21 and 25 years and 48 (24.9%) students were between 16 and 20 years. The majority (99.5%) reported negative symptoms of night blindness, and few (0.5%) reported definite positive symptoms of night blindness. Only 2 (1.0%) students out of the whole study group disclosed family history of RP. Sixty-one (31.6%) participants revealed consanguinity; 2 (1%) of them were of first-degree and one (0.5%) of second-degree consanguinity. One hundred and forty-three (74.1%) participants were emmetropic while fifty (25.9%) with minor degrees of ammetropia (±0.5–0.75 diopter). Overall, 188 (97.4%) scored 6/6 best-corrected visual acuity. None of the partinsepants students reviled any degree of color defect. Intraocular pressure in all students was within normal limits. No single student revealed fundus appearance of RP in all 193 candidates and even in those with symptoms of night blindness or family history of RP.
Conclusion: No single RP case with typical fundus appearance and visual functional loss was reported in 193 male and female Sudanese students of Al-Neelain University College of Optometry and Visual Science.

Keywords: Ammetropic, consanguinity, emmetropic, Gabrah, night blindness, optometry, retinitis pigmentosa


How to cite this article:
Gadkariem RE, Saleem M, Osman SM. Screening of retinitis pigmentosa among Sudanese students of Al-Neelain University Eye Hospital, Khartoum, Sudan. Albasar Int J Ophthalmol 2020;7:11-5

How to cite this URL:
Gadkariem RE, Saleem M, Osman SM. Screening of retinitis pigmentosa among Sudanese students of Al-Neelain University Eye Hospital, Khartoum, Sudan. Albasar Int J Ophthalmol [serial online] 2020 [cited 2021 Apr 14];7:11-5. Available from: https://www.bijojournal.org/text.asp?2020/7/1/11/305764




  Introduction Top


Retinitis pigmentosa (RP) describes as a heterogeneous group of inherited retinal dystrophies characterized by progressive photoreceptor cell degeneration that affects approximately 1 in 4000 in the general population.[1] It causes severe visual impairment. There are severe progressive degeneration of retinal photoreceptors and deposition of retinal pigments, predominantly in the peripheral retina and sparing of the central retina.[1] The genetics of RP is varied; nonsyndromic cases may be inherited as an autosomal dominant (30%), autosomal recessive (20%), X-linked recessive (15%), or sporadic\simplex traits (30%), and 5% may be early onset and grouped as part of leber congenital amaurosis.[2] Three different missense mutations in the coding region of carbonic anhydrase IV have been discovered. The first was a signal sequence mutation, changing Arg14 to Trp (R14W).[3] The other two mutations change amino acids in the mature portion of the protein, replacing Arg69 and Arg219 with His and Ser, respectively (R69H and R219S).[4] In spite of the lack of treatments, regular general eye checkups are imperative for RP patients because people with RP are still at risk for other eye problems which may be treatable. Patients with RP tend to develop cataracts at an earlier age than individuals without RP. There are higher risk of injury, difficulties with timely access to health care, and greater dependency.[1] The symptoms and signs worsen as time goes by. Early symptoms can include night blindness, followed by the loss of peripheral vision and constricted visual fields, which can progress up to tunnel vision or total blindness.


  Materials and Methods Top


In a cross-sectional observational hospital-based study, which was conducted at Al-Neelain University Eye Hospital, Gabrah, Khartoum, Sudan, in 3-month period, from March to May 2017, 193 apparently healthy Sudanese male and female Al-Neelain University College of Optometry and Visual Science students were enrolled in the current study. Other non-Sudanese students or those who refused to be included in the study, besides those with known history of diabetes mellitus, glaucoma, cataract, corneal opacity, corneal abnormalities, history of corneal surgery, current eye infection, or TORCH disease, were excluded. Two visiting students from other universities were also excluded.

The study population was selected by a consecutive stratified sampling technique from a total of 1170 who were representing the total number of Sudanese Faculty of Optometry and Visual Sciences (FOVS) students at the time of data collection. Faculty of Optometry and Visual Sciences (FOVS), after 5 years coarse it awards its graduates the degree of Bachelor of Optometry (BOptom) with honor.

Study setting and area

Al Neelain University Eye Hospital (NEH) was established in 2010 in Gabrah, Khartoum, Sudan; as part of Al Neelain University Faculty of Optometry and Visual Sciences (FOVS). FOVS was established in 1954 under the name of “Institute of Optometry” in Khartoum Eye Teaching Hospital (KETH), then joined Ministry of Higher Education in 1986 as the “high institute of optometry”. In 1997 it was annexed to Al Neelain University and re named: “Faculty of Optometry and Visual Sciences (FOVS)” which awards its graduates; after 5 years coarse, the degree of Bachelor of Optometry (BOptom) with honor

After well-informed consent, a detailed medical, ophthalmic, and family history was taken from all 198 participants, including age, gender, defective vision, night blindness, and color vision defects, and reported in predesigned “data collection forms.”

A fully standardized ophthalmic examination was conducted. Best-corrected visual acuity (BCVA) was assessed using projected Snellen's Chart by Chart Projector (CP; Chart Projector, CP-770; Nidek Co., Ltd, 34-14 Maehama, Hiroishi-Cho, Gamagori, Aichi 443-0038, Japan; www.nidek.com). Color vision test was done by “Ishihara's 38 Plate Book (Medical Equipment India, Kabir Nagar, New Delhi, Item Code: MEI2210). Intraocular pressure (IOP) measurement was checked routinely by Goldmann Applanation Tonometer (Haag-Streit Diagnostics-Applanation Tonometer AT 900®/870 18 Edition/2014-11; HAAG-STREIT AG Gartenstadtstrasse 10 3098 Koeniz, Switzerland, www.haag-streit.com).

Then, systematic slit-lamp (Haag-Streit Diagnostics-Slit Lamp BQ 900/870 18./2014-11; HAAG-STREIT AG Gartenstadtstrasse 10 3098 Koeniz, Switzerland, www.haag-streit.com) biomicroscopic examination for the anterior segment was done for all candidates, followed by fully dilated fundal examination using 1 or 2 drops of 1% tropicamide-ophthalmic eye drops in both eyes, 10 min before an eye examination (Mydriacyl® (Tropicamide ophthalmic solution, USP; NDC Code(s): 0998-0355-15. Alcon Laboratories, Inc. Hünenberg, Switzerland, Fort Worth, Texas, USA). The fundoscopy was done using: (i) Keeler Specialist Direct Ophthalmoscope (The Keeler Specialist Ophthalmologist; Keeler Instruments Inc. Ltd, 456 Parkway Broomall, PA 19008, USA; www.keelerusa.com) and (ii) and slit-lamp Haag-Streit biomicroscopic fundoscopy using +90 and +78 diopter lenses (V90C, V78C; Volk Optical Inc., 7893, OH 44060, USA, www: [email protected]).

Data were statistically analyzed using the Statistical Package for the Social Sciences (SPSS) for Windows, version 20 (manufactured by IBM SPSS Inc. PASW Statistics for Windows, version 20, 2015; SPSS Inc., Chicago, IL, USA). Results obtained were presented in tables and figures, with the confidence interval (CI) of 95% and p-value = 0.05. Mean, median, and mode were used to explain demographic variables.

Ethical approval was obtained from Al-Neelain University FOVS administration; verbal consent was obtained from the participants after full explanation of the study objectives and procedures. Confidentiality and anonymity of each candidate identity were adhered.


  Results Top


In total, 193 (486 eyes) of an apparently healthy Sudanese male and female students from Al-Neelain University College of Optometry and Visual Science were examined in the current study. Females were dominating; 154 (79.8%) were females and 39 (20.2%) were males [Table 1] and [Figure 1]. The mean age of the study group was 21.76 years ± 2.5 years (range: 16–25 years). One hundred and forty-five (75.1%) students were between 21 and 25 years and 48 students (24.9%) were between 16 and 20 years [Table 2] and [Figure 2]. The majority (99.5%) reported negative symptoms of night blindness, and few (0.5%) reported definite positive symptoms of night blindness [Table 3] and [Figure 3]. Only 2 (1.0%) students out of the whole study group disclosed family history of RP [Table 4]. Sixty-one (31.6%) participants revealed consanguinity; 2 (1%) of them were of first-degree and one (0.5%) of second-degree consanguinity [Table 5].
Figure 1: Sex distribution of the study population

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Table 1: Age group distribution of the study population

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Figure 2: Age group distribution of the study population

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Table 2: Distribution of ‘Night Blindness’ among the study Population

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Figure 3: Distribution of night blindness symptoms among the study population

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Table 3: Those with and without family history of retinitis pigmentosa

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Table 4: Distribution of consanguinity in the study population

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Table 5: Distribution of emmetropic versus ammetropic in the study population

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One hundred forty-three (74.1%) participants were emmetropic while fifty (25.9%) with minor degrees of ammetropic (±0.5–0.75 diopter); only five (2.6%) students from the ammetropic group were wearing glasses for this minor refractive errors; their BCVA scored 6/9 in four and 6/18 in one student. The rest of the fifty (n = 45) ammetropic candidates scored 6/6 visual acuity (VA) with pinhole (PH) tests. Overall, 188 students (97.4%) scored 6/6 VA without correction or with PH tests (143 emmetropes + 45 minor ammetropes) who were not wearing glasses [Table 6]. No student record color vision defect by Ishihara's 38 plates color vision tests. The IOP in all students was within normal limits with an average of 15 mmHg (range, 10–20 mmHg) with no significant differences between right and left eyes.
Table 6: Distribution of the best-corrected visual acuity in the study population

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Both direct ophthalmoscopy and biomicroscopic fundoscopy, with +90 and +78 diopter lenses, revealed quite normal fundoscopy without fundus appearance of RP in all 193 candidates and even in those with symptoms of night blindness or family history of RP.


  Discussion Top


RP like other hereditary retinal diseases is considered to be one of the important causes of blindness in the young working-age population.[5],[6],[7] Early stages of the disease are characterized by night blindness and constricted visual fields. In later stages, affected patients typically show abnormal accumulation of pigment in the mid-peripheral retina where rod photoreceptors are normally at the highest density.[8] The importance of screening RP in young communities is now widely realized to be very important to detect those affected groups as the disease mostly influenced the patients' daily life and future.[9]

Although the current study reported 2 cases of family history of RP, one case of night blindness, and 61 cases with variable degrees of consanguinity, which increase the probability of RP affection, still no single case of RP was reported in any of the 193 students. This can be explained by the fact that all university students routinely receive good medical checkup on their admission to the scientific colleges and usually advise to change the college if they proved to have RP or any genetic disease that might compromise their visual perfection and affect the future career.

In the current study no case of RP was reported between the 193 participant students of the Faculty of Optometry and Visual Sciences (FOVS), giving 0.00% rate of RP in these group. This result was in contrary with all national and international studies. However, other reports from Sudan estimated RP to be = 0.037%; [10, 11] which it was compatible with other African and non African countries with almost similar ethnicity: like Ethiopia (0.037%), Chad (0.037%), Saudi Arabia (0.037%) and Colombia (0.037%). [10] While the lowest estimate was found in England, estimated RP (0.025%).[10] One of the biggest worldwide RP screening was the 'Beijing population based, cross sectional cohort Eye Study' by Xu L and colleagues, (Northern China;2006) who reported an incidence rate of 0.1%.[6] The limitation of the current study was the small study size, the selected population that might be already well filtered to exclude affected participants with chronic visually compromised, besides in complete examination, for example, visual field examinations and fundal photography.


  Conclusion Top


No single RP case with typical fundus appearance and visual functional loss was reported in 193 male and female Sudanese students of Al-Neelain University College of Optometry and Visual Science.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Hamel C. Retinitis pigmentosa. Orphanet J Rare Dis 2006;1:40.  Back to cited text no. 1
    
2.
Daiger SP, Bowne SJ, Sullivan LS. Perspective on genes and mutations causing retinitis pigmentosa. Arch Ophthalmol 2007;125:151-8.  Back to cited text no. 2
    
3.
Rebello G. Apoptosis-inducing signal sequence mutation in carbonic anhydrase IV indentified in patients with the RP17 form of retinitis pigmentosa. Proc Natl Sci USA 2004;101:6617-22.  Back to cited text no. 3
    
4.
Yang Z, Alvarez BV, Chakarova C, Jiang L, Karan G, Frederick JM, et al. Mutant carbonic anhydrase 4 impairs pH regulation and causes retinal photoreceptor degeneration. Hum Mol Genet 2005;14:255-65.  Back to cited text no. 4
    
5.
Haim M. Epidemiology of retinitis pigmentosa in Denmark. Acta Ophthalmol Scand Suppl 2002; Volume 80; issue 233, PP:1 34.  Back to cited text no. 5
    
6.
Xu L, Hu L, Ma K, Li J, Jonas JB. Prevalence of retinitis pigmentosa in urban and rural adult Chinese: The Beijing Eye Study. Eur J Ophthalmol 2006;16:865-6.  Back to cited text no. 6
    
7.
Strong? S, Liew G, Michaelides M. Retinitis pigmentosa-associated cystoid macular oedema: Pathogenesis and avenues of intervention. Br J Ophthalmol 2017;101:31-7.  Back to cited text no. 7
    
8.
Sugawara T, Hagiwara A, Hiramatsu A, Ogata K, Mitamura Y, Yamamoto S. Relationship between peripheral visual field loss and vision-related quality of life in patients with retinitis pigmentosa. Eye (Lond) 2010;24:535-9.  Back to cited text no. 8
    
9.
Burstedt MS, Mönestam E, Sandgren O. Associations between specific measures of vision and vision-related quality of life in patients with bothnia dystrophy, a defined type of retinitis pigmentosa. Retina 2005;25:317-23.  Back to cited text no. 9
    
10.
Vaidya P, Vaidya A. Retinitis pigmentosa: Disease encumbrance in the eurozone. Vaidya and Vaidya. Int J Ophthalmol Clin Res 2015;2:3.  Back to cited text no. 10
    
11.
Mohamed ZD, Binnawi KH, Abdu M. Prevalence and causes of Childhood Blindness and Visual Impairment in in Quranic Boarding Schools in Al-Gazira State of Sudan Al-Gazira. Sudanese J Ophthalmol 2017; 9;44-9.  Back to cited text no. 11
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

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