Faculty of Health and Life Sciences Degree project work The Prevalence of Anterior Segment and Crystalline Lens Changes in a Nicaraguan Population Author:Georgette Nisa Subject:Optometry Level:First cycle No:2016:O20 i Prevalence of Anterior Segment and Crystalline Lens Changes in a Nicaraguan Population Georgette Nisa Supervisor: Karthikeyan Baskaran Department of medicine and Optometry PhD, Senior Lecturer Linnaeus University SE- 391 82 Kalmar Sweden Examiner: Peter Gierow Department of medicine and Optometry Professor, FAAO Linnaeus University SE- 391 82 Kalmar Sweden The Examination Project Work is included in the Optometrist study program, 180 hp Abstract Aim: The purpose of this study was to find the prevalence of different ocular changes in the anterior segment of the eye and changes in the crystalline lens among Nicaraguan population. Method: The study was done during a journey to Nicaragua with the organization VFA and Synoptik that lasted for two weeks in March/April. There were a total of 134 participants with 71 females and 63 males. The average age of the study participants was 50 (±20) years and the age ranged from 7 to 97 years. The total sample size was collected in the three towns that we visited during the journey: Ticuantepe, Léon and Estéli. The changes were evaluated by direct ophthalmoscopy. Conjunctiva was examined by asking the patients to look into different gaze directions. Cornea and crystalline lens was examined by asking the patient to look directly at the ophthalmoscope. Results: 31% out of the participants enrolled in this study were healthy with no visible ocular changes. The remaining 69% had ocular changes with majority of them having either cataract, pterygium or pinguecula. The prevalence of cataract was 24%, pterygium 20%, pinguecula 10%. There were other minor ocular changes such as red eye in 4%, arcus senilis in 4%, ptosis in 1%, and aphakia in 1% seen in these participants. Conclusion: The UV related changes had the highest prevalence. This study like previous studies have shown that cataract was most prevalent ocular change in this population. Keywords Vision For All, Ocular Changes, Cataract, Pterygium, Pinguecula, Nicaragua. i Sammanfattning Syftet: Syftet med denna studie var att undersöka prevalensen av förändringar i ögats främre segment samt i den kristallina linsen hos befolkningen i Nicaragua. Metod: Studien genomfördes under en resa till Nicaragua med organisationen VFA och Synoptik. Resan skedde i mars/april och varade i två veckor, där städerna Ticuantepe, Estéli och Léon besöktes. Studien hade totalt 134 deltagare från alla tre städerna varav 71 kvinnor och 63 män med en åldersspridning på 7-97 år. Bedömningen av förändringarna gjordes med hjälp av ett oftalmoskop genom att be patienterna att följa examinatorns finger med blicken på olika riktningar. För bedömning av corneala och lentikulära förändringar fick patienterna titta rakt fram på oftalmoskopet. Resultat: 31% av deltagarna hade friska ögon utan några förändringar. De vanligaste okulära förändringar som upptäcktes i denna studie var katarakt, pterygium och pinguecula. Prevalensen av katarakt var 24%, pterygium 20% och pinguecula 10%. De andra förändringar som upptäcktes bland befolkningen var röda ögon 4%, ptos 1%, arcus senilis 4% och afaki1%. Det fanns ingen signifikant skillnad mellan män och kvinnor i de olika förändringarna. Slutstats: Den högsta prevalens av förändringar var bland de UV relaterad förändringar. Denna studie precis som tidigare studier visar att katarakt är det mest prevalenta ögonförändringen bland denna befolkning. ii Thanks/ Acknowledgements I would like to thank my supervisor Karthikeyan Baskaran for all the help throughout the entire project and for his advices. I thank all my amazing co-travelers to Nicaragua: John Godoy, Sara Thoresson, Hege Welin, Maud Arvidsson, Jaime Hellqvist, Camilla Efraimsson, Tomas Hjalmarson, Mona Lundgren, Andreas Johansson and Åsa Mårtensson. It was such a great and memorable experience. I am thankful to Synoptik and VFA for making this journey and study possible I also want to thank my wonderful classmates for an exciting and fun three years together. Big thanks to my parents, siblings and the entire family for all their love, motivation and always be there for me. Finally I would like to thank my Fiancé and soon to be husband Armel Fungula for his support, encouragement and motivation throughout the entire study. iii Contents 1 Introduction _________________________________________________________ 1 1.1 Anatomy of the Eye _______________________________________________ 1 1.1.1 Eyelid _______________________________________________________ 1 1.1.2 Conjunctiva __________________________________________________ 2 1.1.3 Cornea ______________________________________________________ 2 1.1.4 Iris _________________________________________________________ 3 1.1.5 Crystalline Lens _______________________________________________ 4 1.2 Ocular Changes __________________________________________________ 4 1.2.1 Ptosis _______________________________________________________ 4 1.2.2 Red eye ______________________________________________________ 4 1.2.3 Pinguecula ___________________________________________________ 5 1.2.4 Pterygium ___________________________________________________ 6 1.2.5 Arcus Senilis _________________________________________________ 7 1.2.6 Cataract _____________________________________________________ 8 1.3 Vision for All ____________________________________________________ 8 1.4 Nicaragua _______________________________________________________ 9 1.5 Previous Studies __________________________________________________ 9 2 Aim _______________________________________________________________ 11 3 Methods ___________________________________________________________ 12 3.1 Patients ________________________________________________________ 12 3.2 Materials _______________________________________________________ 12 4 Results _____________________________________________________________ 14 5 Discussion __________________________________________________________ 17 6 Conclusion _________________________________________________________ 20 References ___________________________________________________________ 21 Appendix _____________________________________________________________ I iv 1 Introduction Changes in different parts of the eye occur gradually as we get older and they are due to different factors such as age, sicknesses, trauma, infections and exposure to UV radiation. 1.1 Anatomy of the Eye The human eye is divided into thirteen different parts (see figure 1). It is spherical, consists of three coats with different structures and has 24 mm as a mean diameter. The cornea and sclera make up the outer coat, the second coat consists of the uveal tract which is made up of the iris, choroid and the ciliary body. The third and inner coat of the eye includes the retina, macula fovea and the optic disc (Forrester, 2002). figure 1 Schematic diagram of different parts of the eye. (Modified from google, glaucoma.org) 1.1.1 Eyelid The eyelid is a thin skin that covers and protects the anterior surface of the eye from injury and foreign bodies. Other functions of the eyelid are regulation of the amount of light that enters the eye, distribution of tear film on the cornea during blinking and the drainage of tears. The motion of the eyelid is mostly vertical but there is also a horizontal motion of the eyelid that occurs during blinking. This enables the sweeping of the tears towards the superior and inferior puncta along the lid margin. Fibrous tissue also known as the tarsal plate make up the eyelid´s fibrous layer and this gives a firm shape to the eyelid. Because there is a more developed tarsal plate collagen 1 in the upper lid, it enables the lid to be everted. The structure of the eyelid is divided into six parts: skin, subcutaneous layer, muscles, sub muscular areolar layer, fibrous layer, and palpebral conjunctiva. The eyelid has a very elastic, thin and fat free skin composed of dermis, epidermis and subcutaneous tissue. Due to the delicacy and thinness of the skin, the eyelid is susceptible to pathology. (Bergmanson, 2012, p 30). 1.1.2 Conjunctiva The conjunctiva provides a smooth surface to facilitate the sliding of the eyelid every time the eye blinks (Remington, 2005 p 170). It is a thin mucous membrane that stretches from the limbus to the margin of the eyelid and covers the eye ball (Lawrenson, 2010 p, 10). Palpebral, fornix and the bulbar conjunctiva are the three regions of the conjunctiva. The palpebral conjunctiva has many blood vessels and is attached to the tarsal; it also covers the inner eyelid. The bulbar conjunctiva covers the eye ball all the way to the limbus, it can freely move because it is loosely attached to the Tenon´s capsule. The fornix conjunctiva connects both the palpebral and bulbar conjunctiva from the transition of the eyelid to the eye ball (Kanski, 2011, p 132). The conjunctiva is an important protection of the eye because it serves as a barrier for microorganisms and foreign bodies. It is the most active immunological tissue on the outer part of the eye because it contains many immunological cells (Bergmanson, 2012, p 38). 1.1.3 Cornea The cornea is normally transparent with no muscles or blood vessels and is very sensitive due to the many nerves that are present in its stroma and epithelium. (Kanski, 2011 p 168). It protects the eye from outer influences and has approximately 42 dioptres which stands for two thirds