{"id":1756,"date":"2026-10-20T08:50:50","date_gmt":"2026-10-20T08:50:50","guid":{"rendered":"https:\/\/laseristanbulclinic.com\/eye-glossary\/"},"modified":"2026-10-20T12:55:35","modified_gmt":"2026-10-20T12:55:35","slug":"eye-glossary","status":"publish","type":"page","link":"https:\/\/laseristanbulclinic.com\/en\/eye-glossary\/","title":{"rendered":"Eye glossary A\u2013Z"},"content":{"rendered":"<!-- Hero (Photo + summary card) Start -->\n<section class=\"page-hero\" id=\"top\">\n\t<div class=\"phero-inner pad with-media container-fluid\"><div class=\"row\">\n\t\t<div class=\"phero-left col-12 col-lg-7\">\n\t\t\t<div data-hero-in><ol class=\"crumbs\" aria-label=\"Breadcrumb\"><li><a href=\"https:\/\/laseristanbulclinic.com\/en\/\">Home: eye surgery in Istanbul<\/a><\/li><li><a href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/\">Knowledge centre<\/a><\/li><li><span aria-current=\"page\">Eye glossary A\u2013Z<\/span><\/li><\/ol><\/div>\t\t\t<h1 class=\"t64 hero-title phero-title\" data-lines>Eye Glossary A\u2013Z: Eye Terms, Parts and Diseases Explained<\/h1>\n\t\t\t\t\t\t<ul class=\"phero-meta\" data-hero-in><li><svg width=\"16\" height=\"16\" aria-hidden=\"true\"><use href=\"#i-check\"\/><\/svg>Medically reviewed by <span class=\"ph\">{{surgeon}}<\/span> \u00b7 Last updated <span class=\"ph\">{{date}}<\/span><\/li><\/ul>\t\t<\/div>\n\t\t<div class=\"phero-right has-media col-12 col-lg-5\">\n\t\t\t\t\t\t<figure class=\"phero-media\" data-hero-in><img decoding=\"async\" width=\"640\" height=\"640\" src=\"https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/eye-iris-illustration-light.webp\" class=\"attachment-large size-large\" alt=\"Illustration of an iris on a light background\" fetchpriority=\"high\" srcset=\"https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/eye-iris-illustration-light.webp 1000w, https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/eye-iris-illustration-light-300x300.webp 300w, https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/eye-iris-illustration-light-150x150.webp 150w, https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/eye-iris-illustration-light-768x768.webp 768w\" sizes=\"(max-width: 640px) 100vw, 640px\" \/><\/figure>\n\t\t\t\t\t\t\t\t\t<div class=\"inshort\" data-hero-in><p>This eye glossary explains 67 eye terms in plain English: the parts of the eye, the numbers on a glasses prescription, and the common and less common eye diseases. Each entry gives a short definition and links to a full page. The terms are checked by Laser Istanbul Clinic&#8217;s three eye surgeons, Prof. Dr. Ahmet Sat\u0131c\u0131, Do\u00e7. Dr. Muhammet Derda \u00d6zer and Op. Dr. Aysan Bayram. A glossary explains words; only an eye examination can tell you what is happening in your own eyes.<\/p><\/div>\n\t\t\t\t\t<\/div>\n\t<\/div><\/div>\n<\/section>\n<!-- Hero (Photo + summary card) End -->\n\n\n<!-- Heading (Text without a heading) Start -->\n<section class=\"psec pad\" id=\"intro\"><div class=\"container-fluid px-0\"><div class=\"row g-0\"><div class=\"col-12\"><div class=\"gen-intro prose\"><p data-reveal>Eye reports and prescriptions are full of words that nobody explains: sphere, axis, macula, zonules, uveitis. This eye glossary puts those words in one place. Every term has a one-line definition below and its own page with the full explanation, so you can read your results, prepare for an appointment or simply understand what your doctor said.<\/p>\n<p data-reveal>The glossary is organised into eight groups instead of one long alphabetical list, because most people arrive with a question rather than a letter: <em>What do the numbers on my prescription mean? Where is the macula? Is a lump on my eyelid a stye?<\/em> Use the group headings to find the area you need, then open the term page.<\/p>\n<p data-reveal>A note on the Turkish titles. &#8220;Prof. Dr.&#8221; means Professor Doctor. &#8220;Do\u00e7. Dr.&#8221; means Associate Professor (Do\u00e7ent) Doctor, and &#8220;Op. Dr.&#8221; means Operator Doctor, the title of a specialist surgeon in T\u00fcrkiye. Where a group below relates to a treatment, we name the surgeon who leads it.<\/p>\n<p data-reveal>This page is for learning, not self-diagnosis. Many eye diseases look alike and some, such as retinal detachment, need treatment within hours. If you have sudden changes in your sight, use the &#8220;when to act fast&#8221; table further down and seek care where you are now.<\/p><div class=\"links-row\" data-reveal><a class=\"link-arrow\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/\">Knowledge centre: all eye health guides <svg width=\"18\" height=\"18\" aria-hidden=\"true\"><use href=\"#i-arrow\"\/><\/svg><\/a><\/div><\/div><\/div><\/div><\/div><\/section>\n<!-- Heading (Text without a heading) End -->\n\n\n<!-- Flexible Section Start -->\n<section class=\"panel\" id=\"eye-terms-by-group\"><div class=\"container-fluid px-0\"><div class=\"row g-0\"><div class=\"col-12\"><div class=\"sec-head is-center row\"><div class=\"col-12\"><h2 class=\"t48 sec-title\" data-reveal>Eye terms by group<\/h2><\/div><\/div><div class=\"features row row-cols-1 row-cols-md-2 row-cols-lg-3\" data-stagger><div class=\"col\"><div class=\"feat h-100\"><span class=\"feat-icon\" aria-hidden=\"true\"><svg width=\"26\" height=\"26\" aria-hidden=\"true\"><use href=\"#i-lens\"\/><\/svg><\/span><h3>Reading your prescription and how the eye focuses<\/h3><p>How strong your glasses are, why reading gets harder after 40, and the lens types that correct it. Refractive questions (glasses, laser and lens surgery) are handled by Prof. Dr. Ahmet Sat\u0131c\u0131 and Op. Dr. Aysan Bayram, who both perform laser vision correction.<\/p><div class=\"btn-row\"><\/div><a class=\"feat-go\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/laser-eye-surgery\/\">Laser eye surgery guides <svg width=\"18\" height=\"18\" aria-hidden=\"true\"><use href=\"#i-arrow\"\/><\/svg><\/a><\/div><\/div><div class=\"col\"><div class=\"feat h-100\"><span class=\"feat-icon\" aria-hidden=\"true\"><svg width=\"26\" height=\"26\" aria-hidden=\"true\"><use href=\"#i-sun\"\/><\/svg><\/span><h3>Parts of the eye (anatomy)<\/h3><p>The structures light passes through, from the clear front window to the nerve that carries the picture to the brain.<\/p><div class=\"btn-row\"><\/div><\/div><\/div><div class=\"col\"><div class=\"feat h-100\"><span class=\"feat-icon\" aria-hidden=\"true\"><svg width=\"26\" height=\"26\" aria-hidden=\"true\"><use href=\"#i-lens\"\/><\/svg><\/span><h3>Eye pressure, glaucoma and cataract<\/h3><p>Cataract is a clouded lens; glaucoma is damage to the optic nerve. Cataract is treated by all three of our surgeons; glaucoma is led by Prof. Dr. Ahmet Sat\u0131c\u0131.<\/p><div class=\"btn-row\"><\/div><a class=\"feat-go\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/lens-and-cataract\/\">Lens and cataract guides <svg width=\"18\" height=\"18\" aria-hidden=\"true\"><use href=\"#i-arrow\"\/><\/svg><\/a><\/div><\/div><div class=\"col\"><div class=\"feat h-100\"><span class=\"feat-icon\" aria-hidden=\"true\"><svg width=\"26\" height=\"26\" aria-hidden=\"true\"><use href=\"#i-eye\"\/><\/svg><\/span><h3>Cornea and the surface of the eye<\/h3><p>Conditions of the clear front window and the membrane that covers the white of the eye. Cornea conditions are led by Do\u00e7. Dr. Muhammet Derda \u00d6zer.<\/p><div class=\"btn-row\"><\/div><a class=\"feat-go\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/keratoconus-cornea\/\">Keratoconus and cornea guides <svg width=\"18\" height=\"18\" aria-hidden=\"true\"><use href=\"#i-arrow\"\/><\/svg><\/a><\/div><\/div><div class=\"col\"><div class=\"feat h-100\"><span class=\"feat-icon\" aria-hidden=\"true\"><svg width=\"26\" height=\"26\" aria-hidden=\"true\"><use href=\"#i-car\"\/><\/svg><\/span><h3>Eyelid conditions<\/h3><p>Lumps, bumps and position problems of the eyelids. Eyelid and oculoplastic care is led by Prof. Dr. Ahmet Sat\u0131c\u0131.<\/p><div class=\"btn-row\"><\/div><a class=\"feat-go\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/eyelids\/\">Eyelid and cosmetic guides <svg width=\"18\" height=\"18\" aria-hidden=\"true\"><use href=\"#i-arrow\"\/><\/svg><\/a><\/div><\/div><div class=\"col\"><div class=\"feat h-100\"><span class=\"feat-icon\" aria-hidden=\"true\"><svg width=\"26\" height=\"26\" aria-hidden=\"true\"><use href=\"#i-eye\"\/><\/svg><\/span><h3>Retina, uvea and optic nerve<\/h3><p>Conditions at the back of the eye and in the eye&#8217;s inner layers. Retina and uveitis care is led by Do\u00e7. Dr. Muhammet Derda \u00d6zer, with Op. Dr. Aysan Bayram for retinal disease.<\/p><div class=\"btn-row\"><\/div><a class=\"feat-go\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/retina-glaucoma\/\">Retina and glaucoma guides <svg width=\"18\" height=\"18\" aria-hidden=\"true\"><use href=\"#i-arrow\"\/><\/svg><\/a><\/div><\/div><div class=\"col\"><div class=\"feat h-100\"><span class=\"feat-icon\" aria-hidden=\"true\"><svg width=\"26\" height=\"26\" aria-hidden=\"true\"><use href=\"#i-heart\"\/><\/svg><\/span><h3>Eye movement, alignment and how the eyes develop<\/h3><p>How the eyes point, move and develop, from childhood vision problems to differences present from birth. Squint (strabismus) surgery is led by Prof. Dr. Ahmet Sat\u0131c\u0131.<\/p><div class=\"btn-row\"><\/div><\/div><\/div><div class=\"col\"><div class=\"feat h-100\"><span class=\"feat-icon\" aria-hidden=\"true\"><svg width=\"26\" height=\"26\" aria-hidden=\"true\"><use href=\"#i-heart\"\/><\/svg><\/span><h3>Symptoms people search for<\/h3><div class=\"btn-row\"><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/section>\n<!-- Flexible Section End -->\n\n\n<!-- Table (Table on a dark panel) Start -->\n<section class=\"panel dark\" id=\"when-to-act-fast-signs-that-should-not-wait-for-an-appointme\"><div class=\"container-fluid px-0\"><div class=\"row g-0\"><div class=\"col-12\">\n\t\t<h2 class=\"t48 sec-title\" data-reveal>When to act fast: signs that should not wait for an appointment<\/h2>\n\t\t\t<p class=\"t22 sec-lead\" data-reveal>This glossary is not an emergency guide, but a few eye problems cannot wait. If you have any of these, seek urgent eye care where you are now, not a trip abroad.<\/p>\n\t\t\t<div class=\"tbl-flow\"><div class=\"tbl-wrap\" data-reveal><table class=\"tbl rsp\"><thead><tr><th scope=\"col\">If you notice\u2026<\/th><th scope=\"col\">It may be\u2026<\/th><th scope=\"col\">What to do<\/th><\/tr><\/thead><tbody><tr><th scope=\"row\">A sudden shower of floaters, flashes of light, or a dark curtain across your vision<\/th><td data-label=\"It may be\u2026\"><a href=\"\/en\/eye-glossary\/retinal-detachment\/\">Retinal detachment<\/a><\/td><td data-label=\"What to do\">Same-day emergency eye care. The NHS says to contact NHS 111 immediately; elsewhere, go to an eye emergency service or hospital.<\/td><\/tr><tr><th scope=\"row\">Sudden, painless loss of vision in one eye<\/th><td data-label=\"It may be\u2026\"><a href=\"\/en\/eye-glossary\/eye-stroke\/\">Eye stroke<\/a><\/td><td data-label=\"What to do\">Emergency care at once. Treatment works best within hours.<\/td><\/tr><tr><th scope=\"row\">A painful red eye with blurred vision or light sensitivity<\/th><td data-label=\"It may be\u2026\"><a href=\"\/en\/eye-glossary\/keratitis\/\">Keratitis<\/a> or <a href=\"\/en\/eye-glossary\/uveitis\/\">uveitis<\/a><\/td><td data-label=\"What to do\">Urgent same-day assessment by an eye doctor.<\/td><\/tr><tr><th scope=\"row\">New double vision<\/th><td data-label=\"It may be\u2026\"><a href=\"\/en\/eye-glossary\/diplopia\/\">Diplopia<\/a><\/td><td data-label=\"What to do\">Prompt assessment; it can have causes outside the eye.<\/td><\/tr><\/tbody><\/table><\/div><p data-reveal>For long-term problems (a slowly worsening prescription, blurred reading vision, cloudy or dim sight, a lump on the eyelid), the term pages explain what to expect and what an examination looks at.<\/p><\/div>\t<\/div><\/div><\/div><\/section>\n<!-- Table (Table on a dark panel) End -->\n\n\n<!-- List (Related pages) Start -->\n<section class=\"psec pad\" id=\"go-deeper-by-topic\"><div class=\"container-fluid px-0\"><div class=\"row g-0\"><div class=\"col-12\">\n\t<div class=\"sec-head is-center row\"><div class=\"col-12\"><h2 class=\"t48 sec-title\" data-reveal>Go deeper by topic<\/h2><\/div><div class=\"col-12\"><p class=\"t22 sec-lead\" data-reveal>In-depth explainers that sit behind the glossary terms:<\/p><\/div><\/div>\t\t<ul class=\"pg-links row row-cols-1 row-cols-sm-2 row-cols-lg-3\" data-stagger>\n\t\t\t\t<li class=\"col\"><a class=\"pg-link\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/comparisons\/\"><span>Comparisons: which eye treatment is right for you<\/span><svg width=\"22\" height=\"22\" aria-hidden=\"true\"><use href=\"#i-arrow-ur\"\/><\/svg><\/a><\/li>\n\t\t\t\t<li class=\"col\"><a class=\"pg-link\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/laser-eye-surgery\/\"><span>Laser eye surgery guides<\/span><svg width=\"22\" height=\"22\" aria-hidden=\"true\"><use href=\"#i-arrow-ur\"\/><\/svg><\/a><\/li>\n\t\t\t\t<li class=\"col\"><a class=\"pg-link\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/lens-and-cataract\/\"><span>Lens and cataract guides<\/span><svg width=\"22\" height=\"22\" aria-hidden=\"true\"><use href=\"#i-arrow-ur\"\/><\/svg><\/a><\/li>\n\t\t\t\t<li class=\"col\"><a class=\"pg-link\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/keratoconus-cornea\/\"><span>Keratoconus and cornea guides<\/span><svg width=\"22\" height=\"22\" aria-hidden=\"true\"><use href=\"#i-arrow-ur\"\/><\/svg><\/a><\/li>\n\t\t\t\t<li class=\"col\"><a class=\"pg-link\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/retina-glaucoma\/\"><span>Retina and glaucoma guides<\/span><svg width=\"22\" height=\"22\" aria-hidden=\"true\"><use href=\"#i-arrow-ur\"\/><\/svg><\/a><\/li>\n\t\t\t\t<li class=\"col\"><a class=\"pg-link\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/eyelids\/\"><span>Eyelid and cosmetic guides<\/span><svg width=\"22\" height=\"22\" aria-hidden=\"true\"><use href=\"#i-arrow-ur\"\/><\/svg><\/a><\/li>\n\t\t\t\t<li class=\"col\"><a class=\"pg-link\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/conditions\/astigmatism-explained\/\"><span>Astigmatism explained<\/span><svg width=\"22\" height=\"22\" aria-hidden=\"true\"><use href=\"#i-arrow-ur\"\/><\/svg><\/a><\/li>\n\t\t\t\t<li class=\"col\"><a class=\"pg-link\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/conditions\/short-sightedness-explained\/\"><span>Short-sightedness (myopia) explained<\/span><svg width=\"22\" height=\"22\" aria-hidden=\"true\"><use href=\"#i-arrow-ur\"\/><\/svg><\/a><\/li>\n\t\t\t\t<li class=\"col\"><a class=\"pg-link\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/conditions\/dry-eyes-causes-and-home-remedies\/\"><span>Dry eyes: causes and home remedies<\/span><svg width=\"22\" height=\"22\" aria-hidden=\"true\"><use href=\"#i-arrow-ur\"\/><\/svg><\/a><\/li>\n\t\t\t\t<li class=\"col\"><a class=\"pg-link\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/conditions\/lazy-eye-in-children-and-adults\/\"><span>Lazy eye (amblyopia) in children and adults<\/span><svg width=\"22\" height=\"22\" aria-hidden=\"true\"><use href=\"#i-arrow-ur\"\/><\/svg><\/a><\/li>\n\t\t\t\t<li class=\"col\"><a class=\"pg-link\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/conditions\/squint-strabismus-causes\/\"><span>Squint \/ strabismus causes<\/span><svg width=\"22\" height=\"22\" aria-hidden=\"true\"><use href=\"#i-arrow-ur\"\/><\/svg><\/a><\/li>\n\t\t\t<\/ul>\n\t<\/div><\/div><\/div><\/section>\n<!-- List (Related pages) End -->\n\n\n<!-- FAQ (FAQ accordion) Start -->\n<section class=\"faq pad\" id=\"faq\"><div class=\"container-fluid px-0\"><div class=\"row g-0\"><div class=\"col-12\"><div class=\"faq-grid\">\n\t<div class=\"faq-side\">\n\t\t\t\t<h2 class=\"t48\" data-reveal>Questions about eye terms and eye diseases<\/h2>\n\t\t\t\t\t\t\t<\/div>\n\t\t<div class=\"acc\" data-stagger>\n\t\t\t\t<div class=\"acc-item is-open\"><h3><button type=\"button\" class=\"t32\" aria-expanded=\"true\" aria-controls=\"faq-3b751eea-a1\" id=\"faq-3b751eea-q1\">What is an eye glossary?<svg width=\"24\" height=\"24\" aria-hidden=\"true\"><use href=\"#i-plus\"\/><\/svg><\/button><\/h3><div class=\"acc-panel\" id=\"faq-3b751eea-a1\" role=\"region\" aria-labelledby=\"faq-3b751eea-q1\"><div class=\"acc-body\"><p data-reveal>An eye glossary is an A\u2013Z style reference that explains eye terms in plain language: the parts of the eye, the words on a prescription or clinic report, and the names of eye diseases. Ours has 67 entries, each with a short definition on this page and a full page of its own. It helps you understand your results, but it does not replace an eye examination.<\/p><\/div><\/div><\/div>\n\t\t\t\t<div class=\"acc-item\"><h3><button type=\"button\" class=\"t32\" aria-expanded=\"false\" aria-controls=\"faq-3b751eea-a2\" id=\"faq-3b751eea-q2\">What are the most common eye diseases?<svg width=\"24\" height=\"24\" aria-hidden=\"true\"><use href=\"#i-plus\"\/><\/svg><\/button><\/h3><div class=\"acc-panel\" id=\"faq-3b751eea-a2\" role=\"region\" aria-labelledby=\"faq-3b751eea-q2\"><div class=\"acc-body\"><p data-reveal>Eye problems that most people meet in their lifetime include refractive errors such as short-sightedness and astigmatism, cataract, dry eye, conjunctivitis, blepharitis and presbyopia. Glaucoma, macular degeneration and diabetic retinopathy matter most for long-term sight. Each has an entry in the groups above: <a href=\"\/en\/eye-glossary\/cataract\/\">cataract<\/a>, <a href=\"\/en\/eye-glossary\/glaucoma\/\">glaucoma<\/a>, <a href=\"\/en\/eye-glossary\/dry-eye-syndrome\/\">dry eye syndrome<\/a>, <a href=\"\/en\/eye-glossary\/conjunctivitis\/\">conjunctivitis<\/a> and <a href=\"\/en\/eye-glossary\/presbyopia\/\">presbyopia<\/a>.<\/p><\/div><\/div><\/div>\n\t\t\t\t<div class=\"acc-item\"><h3><button type=\"button\" class=\"t32\" aria-expanded=\"false\" aria-controls=\"faq-3b751eea-a3\" id=\"faq-3b751eea-q3\">What are the 10 diseases of the eye?<svg width=\"24\" height=\"24\" aria-hidden=\"true\"><use href=\"#i-plus\"\/><\/svg><\/button><\/h3><div class=\"acc-panel\" id=\"faq-3b751eea-a3\" role=\"region\" aria-labelledby=\"faq-3b751eea-q3\"><div class=\"acc-body\"><p data-reveal>There is no official list of ten, but these ten are the ones people ask about most, and all are explained here: <a href=\"\/en\/eye-glossary\/cataract\/\">cataract<\/a>, <a href=\"\/en\/eye-glossary\/glaucoma\/\">glaucoma<\/a>, <a href=\"\/en\/eye-glossary\/macular-degeneration\/\">macular degeneration<\/a>, <a href=\"\/en\/eye-glossary\/diabetic-retinopathy\/\">diabetic retinopathy<\/a>, <a href=\"\/en\/eye-glossary\/dry-eye-syndrome\/\">dry eye syndrome<\/a>, <a href=\"\/en\/eye-glossary\/conjunctivitis\/\">conjunctivitis<\/a>, <a href=\"\/en\/eye-glossary\/keratoconus\/\">keratoconus<\/a>, <a href=\"\/en\/eye-glossary\/retinal-detachment\/\">retinal detachment<\/a>, <a href=\"\/en\/eye-glossary\/blepharitis\/\">blepharitis<\/a> and <a href=\"\/en\/eye-glossary\/uveitis\/\">uveitis<\/a>.<\/p><\/div><\/div><\/div>\n\t\t\t\t<div class=\"acc-item\"><h3><button type=\"button\" class=\"t32\" aria-expanded=\"false\" aria-controls=\"faq-3b751eea-a4\" id=\"faq-3b751eea-q4\">What are the worst eye diseases?<svg width=\"24\" height=\"24\" aria-hidden=\"true\"><use href=\"#i-plus\"\/><\/svg><\/button><\/h3><div class=\"acc-panel\" id=\"faq-3b751eea-a4\" role=\"region\" aria-labelledby=\"faq-3b751eea-q4\"><div class=\"acc-body\"><p data-reveal>There is no official ranking, but the eye diseases that most threaten sight when untreated are the ones that damage the retina, optic nerve or cornea. Cataract is among the leading causes of blindness worldwide, according to the World Health Organization, yet it is treatable with surgery. Glaucoma has no cure, but the NHS says treatment can slow the damage; retinal detachment and <a href=\"\/en\/eye-glossary\/eye-stroke\/\">eye stroke<\/a> are emergencies; diabetic retinopathy and macular degeneration can cause serious sight loss. Early diagnosis changes the outcome in most of them.<\/p><\/div><\/div><\/div>\n\t\t\t\t<div class=\"acc-item\"><h3><button type=\"button\" class=\"t32\" aria-expanded=\"false\" aria-controls=\"faq-3b751eea-a5\" id=\"faq-3b751eea-q5\">Is there a list of rare eye diseases?<svg width=\"24\" height=\"24\" aria-hidden=\"true\"><use href=\"#i-plus\"\/><\/svg><\/button><\/h3><div class=\"acc-panel\" id=\"faq-3b751eea-a5\" role=\"region\" aria-labelledby=\"faq-3b751eea-q5\"><div class=\"acc-body\"><p data-reveal>Rare eye diseases affect only a small share of people, and there are many of them, so no single page can list them all. In this glossary, less common conditions include <a href=\"\/en\/eye-glossary\/retinitis-pigmentosa\/\">retinitis pigmentosa<\/a>, <a href=\"\/en\/eye-glossary\/beh-et-s-eye-disease\/\">Beh\u00e7et&#8217;s eye disease<\/a>, <a href=\"\/en\/eye-glossary\/optic-neuritis\/\">optic neuritis<\/a>, <a href=\"\/en\/eye-glossary\/coloboma\/\">coloboma<\/a> and <a href=\"\/en\/eye-glossary\/nystagmus\/\">nystagmus<\/a>. If you have been given a rare diagnosis, an expert second opinion is worth having.<\/p><\/div><\/div><\/div>\n\t\t\t\t<div class=\"acc-item\"><h3><button type=\"button\" class=\"t32\" aria-expanded=\"false\" aria-controls=\"faq-3b751eea-a6\" id=\"faq-3b751eea-q6\">How do I read my glasses prescription?<svg width=\"24\" height=\"24\" aria-hidden=\"true\"><use href=\"#i-plus\"\/><\/svg><\/button><\/h3><div class=\"acc-panel\" id=\"faq-3b751eea-a6\" role=\"region\" aria-labelledby=\"faq-3b751eea-q6\"><div class=\"acc-body\"><p data-reveal>A prescription has up to three main numbers per eye. <a href=\"\/en\/eye-glossary\/sphere\/\">Sphere (SPH)<\/a> is the main power, written in <a href=\"\/en\/eye-glossary\/dioptre\/\">dioptres<\/a>: minus for short-sightedness, plus for long-sightedness. <a href=\"\/en\/eye-glossary\/cylinder\/\">Cylinder (CYL)<\/a> corrects astigmatism, and <a href=\"\/en\/eye-glossary\/axis\/\">axis<\/a> gives its direction in degrees. Reading glasses add a further &#8220;add&#8221; power for <a href=\"\/en\/eye-glossary\/presbyopia\/\">presbyopia<\/a>.<\/p><\/div><\/div><\/div>\n\t\t\t\t<div class=\"acc-item\"><h3><button type=\"button\" class=\"t32\" aria-expanded=\"false\" aria-controls=\"faq-3b751eea-a7\" id=\"faq-3b751eea-q7\">Can I recognise an eye disease from pictures?<svg width=\"24\" height=\"24\" aria-hidden=\"true\"><use href=\"#i-plus\"\/><\/svg><\/button><\/h3><div class=\"acc-panel\" id=\"faq-3b751eea-a7\" role=\"region\" aria-labelledby=\"faq-3b751eea-q7\"><div class=\"acc-body\"><p data-reveal>Not reliably. Pictures can point you in a direction, but many eye conditions look alike: a <a href=\"\/en\/eye-glossary\/stye\/\">stye<\/a> and a <a href=\"\/en\/eye-glossary\/chalazion\/\">chalazion<\/a> are both eyelid lumps, and a <a href=\"\/en\/eye-glossary\/pinguecula\/\">pinguecula<\/a> and a <a href=\"\/en\/eye-glossary\/pterygium\/\">pterygium<\/a> are both growths on the white of the eye, yet they are managed differently. Use the definitions here to understand the terms, and let an eye examination tell you which one you have.<\/p><\/div><\/div><\/div>\n\t\t\t\t<div class=\"acc-item\"><h3><button type=\"button\" class=\"t32\" aria-expanded=\"false\" aria-controls=\"faq-3b751eea-a8\" id=\"faq-3b751eea-q8\">Which of these conditions do your surgeons treat?<svg width=\"24\" height=\"24\" aria-hidden=\"true\"><use href=\"#i-plus\"\/><\/svg><\/button><\/h3><div class=\"acc-panel\" id=\"faq-3b751eea-a8\" role=\"region\" aria-labelledby=\"faq-3b751eea-q8\"><div class=\"acc-body\"><p data-reveal>Between them, our three surgeons treat cataract, lens and laser vision correction, cornea and keratoconus, retina and uveitis, glaucoma, eyelid conditions and squint. Prof. Dr. Ahmet Sat\u0131c\u0131 leads laser, lens, glaucoma, eyelid and squint surgery; Do\u00e7. Dr. Muhammet Derda \u00d6zer leads cornea, keratoconus, retina and uveitis care; Op. Dr. Aysan Bayram treats cataract, laser and retinal disease. Not every term in this glossary needs surgery: many are explained simply so you know what you are looking at.<\/p><div class=\"links-row\" data-reveal><a class=\"link-arrow\" href=\"https:\/\/laseristanbulclinic.com\/en\/eye-health\/\">Knowledge centre: all eye health guides <svg width=\"18\" height=\"18\" aria-hidden=\"true\"><use href=\"#i-arrow\"\/><\/svg><\/a><\/div><\/div><\/div><\/div>\n\t\t\t<\/div>\n\t<\/div><\/div><\/div><\/div><script type=\"application\/ld+json\">{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[{\"@type\":\"Question\",\"name\":\"What is an eye glossary?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"An eye glossary is an A\u2013Z style reference that explains eye terms in plain language: the parts of the eye, the words on a prescription or clinic report, and the names of eye diseases. Ours has 67 entries, each with a short definition on this page and a full page of its own. It helps you understand your results, but it does not replace an eye examination.\"}},{\"@type\":\"Question\",\"name\":\"What are the most common eye diseases?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Eye problems that most people meet in their lifetime include refractive errors such as short-sightedness and astigmatism, cataract, dry eye, conjunctivitis, blepharitis and presbyopia. Glaucoma, macular degeneration and diabetic retinopathy matter most for long-term sight. Each has an entry in the groups above: cataract, glaucoma, dry eye syndrome, conjunctivitis and presbyopia.\"}},{\"@type\":\"Question\",\"name\":\"What are the 10 diseases of the eye?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"There is no official list of ten, but these ten are the ones people ask about most, and all are explained here: cataract, glaucoma, macular degeneration, diabetic retinopathy, dry eye syndrome, conjunctivitis, keratoconus, retinal detachment, blepharitis and uveitis.\"}},{\"@type\":\"Question\",\"name\":\"What are the worst eye diseases?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"There is no official ranking, but the eye diseases that most threaten sight when untreated are the ones that damage the retina, optic nerve or cornea. Cataract is among the leading causes of blindness worldwide, according to the World Health Organization, yet it is treatable with surgery. Glaucoma has no cure, but the NHS says treatment can slow the damage; retinal detachment and eye stroke are emergencies; diabetic retinopathy and macular degeneration can cause serious sight loss. Early diagnosis changes the outcome in most of them.\"}},{\"@type\":\"Question\",\"name\":\"Is there a list of rare eye diseases?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Rare eye diseases affect only a small share of people, and there are many of them, so no single page can list them all. In this glossary, less common conditions include retinitis pigmentosa, Beh\u00e7et's eye disease, optic neuritis, coloboma and nystagmus. If you have been given a rare diagnosis, an expert second opinion is worth having.\"}},{\"@type\":\"Question\",\"name\":\"How do I read my glasses prescription?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"A prescription has up to three main numbers per eye. Sphere (SPH) is the main power, written in dioptres: minus for short-sightedness, plus for long-sightedness. Cylinder (CYL) corrects astigmatism, and axis gives its direction in degrees. Reading glasses add a further \\\"add\\\" power for presbyopia.\"}},{\"@type\":\"Question\",\"name\":\"Can I recognise an eye disease from pictures?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Not reliably. Pictures can point you in a direction, but many eye conditions look alike: a stye and a chalazion are both eyelid lumps, and a pinguecula and a pterygium are both growths on the white of the eye, yet they are managed differently. Use the definitions here to understand the terms, and let an eye examination tell you which one you have.\"}},{\"@type\":\"Question\",\"name\":\"Which of these conditions do your surgeons treat?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Between them, our three surgeons treat cataract, lens and laser vision correction, cornea and keratoconus, retina and uveitis, glaucoma, eyelid conditions and squint. Prof. Dr. Ahmet Sat\u0131c\u0131 leads laser, lens, glaucoma, eyelid and squint surgery; Do\u00e7. Dr. Muhammet Derda \u00d6zer leads cornea, keratoconus, retina and uveitis care; Op. Dr. Aysan Bayram treats cataract, laser and retinal disease. Not every term in this glossary needs surgery: many are explained simply so you know what you are looking at.\"}}]}<\/script><\/section>\n<!-- FAQ (FAQ accordion) End -->\n\n\n<!-- List (Sources and medical review) Start -->\n<section class=\"psec pad tight\"><div class=\"container-fluid px-0\"><div class=\"row g-0\"><div class=\"col-12\"><details class=\"sources\" data-reveal><summary class=\"t22\">Sources for the facts on this page<\/summary><ol>\n\t\t<li><strong>American Academy of Ophthalmology, &#8220;Parts of the Eye&#8221;<\/strong> (anatomy functions: cornea, sclera, conjunctiva, iris and pupil, lens, zonules, vitreous, retina, macula, optic nerve). https:\/\/www.aao.org\/eye-health\/anatomy\/parts-of-eye<\/li>\n\t\t<li><strong>National Eye Institute, &#8220;How the eyes work&#8221;<\/strong> (cornea bends light; iris and pupil; lens; retina; optic nerve). https:\/\/www.nei.nih.gov\/learn-about-eye-health\/healthy-vision\/how-eyes-work<\/li>\n\t\t<li><strong>American Academy of Ophthalmology, &#8220;What Is Presbyopia?&#8221;<\/strong>: loss of close focus; most people notice it shortly after 40. https:\/\/www.aao.org\/eye-health\/diseases\/what-is-presbyopia<\/li>\n\t\t<li><strong>American Academy of Ophthalmology, &#8220;Ocular Hypertension&#8221;<\/strong>: eye pressure higher than normal with a normal-looking optic nerve; raises glaucoma risk but is not glaucoma. https:\/\/www.aao.org\/eye-health\/diseases\/ocular-hypertension<\/li>\n\t\t<li><strong>NHS, &#8220;Cataracts&#8221;<\/strong>: cloudy lens, blurred vision, surgery under local anaesthetic. https:\/\/www.nhs.uk\/conditions\/cataracts\/<\/li>\n\t\t<li><strong>Cambridge University Hospitals NHS Foundation Trust, &#8220;YAG laser posterior capsulotomy following cataract surgery&#8221;<\/strong>: posterior capsule opacification, quick painless YAG laser treatment. https:\/\/www.cuh.nhs.uk\/patient-information\/yag-laser-posterior-capsulotomy-following-cataract-surgery\/<\/li>\n\t\t<li><strong>Leeds Teaching Hospitals NHS Trust, &#8220;Keratoconus &amp; corneal cross-linking&#8221;<\/strong>: keratoconus usually starts in the teenage years; cross-linking stabilises it. https:\/\/www.leedsth.nhs.uk\/patients\/resources\/keratoconus-corneal-cross-linking\/<\/li>\n\t\t<li><strong>NHS, &#8220;Conjunctivitis&#8221;<\/strong>: infection or allergy; infectious forms contagious, allergic not. https:\/\/www.nhs.uk\/conditions\/conjunctivitis\/<\/li>\n\t\t<li><strong>NHS, &#8220;Blepharitis&#8221;<\/strong>: swollen, itchy eyelids; not contagious; often comes and goes. https:\/\/www.nhs.uk\/conditions\/blepharitis\/<\/li>\n\t\t<li><strong>NHS, &#8220;Stye&#8221;<\/strong>: a small, painful lump; a hard, not very painful lump is more likely a chalazion. https:\/\/www.nhs.uk\/conditions\/stye\/<\/li>\n\t\t<li><strong>NHS, &#8220;Dry eyes&#8221;<\/strong>: not enough tears or tears evaporating too quickly. https:\/\/www.nhs.uk\/conditions\/dry-eyes\/<\/li>\n\t\t<li><strong>NHS, &#8220;Retinal detachment&#8221;<\/strong>: floaters, flashes, dark curtain; contact NHS 111 immediately. https:\/\/www.nhs.uk\/conditions\/retinal-detachment\/<\/li>\n\t\t<li><strong>American Academy of Ophthalmology, &#8220;What Are Floaters and Flashes?&#8221;<\/strong>: floaters are shadows from clumps in the vitreous; sudden new floaters, a shadow or curtain need urgent care; jagged lines may be migraine. https:\/\/www.aao.org\/eye-health\/diseases\/what-are-floaters-flashes<\/li>\n\t\t<li><strong>NHS, &#8220;Age-related macular degeneration (AMD)&#8221;<\/strong>: affects central vision; does not cause total blindness. https:\/\/www.nhs.uk\/conditions\/age-related-macular-degeneration-amd\/<\/li>\n\t\t<li><strong>NHS, &#8220;Diabetic retinopathy&#8221;<\/strong>: caused by diabetes; early detection and treatment reduces risk of sight loss. https:\/\/www.nhs.uk\/conditions\/diabetic-retinopathy\/<\/li>\n\t\t<li><strong>American Academy of Ophthalmology, &#8220;What Is a Retinal Artery Occlusion?&#8221;<\/strong>: sudden, painless vision loss; emergency; treatment most effective within hours. https:\/\/www.aao.org\/eye-health\/diseases\/stroke-affecting-eye<\/li>\n\t\t<li><strong>American Academy of Ophthalmology, &#8220;What Is Uveitis?&#8221;<\/strong>: inflammation of the uvea; red eye, light sensitivity, blurred vision. https:\/\/www.aao.org\/eye-health\/diseases\/what-is-uveitis<\/li>\n\t\t<li><strong>NHS, &#8220;Lazy eye&#8221;<\/strong>: vision in one eye does not develop properly; treatment ideally before age 7. https:\/\/www.nhs.uk\/conditions\/lazy-eye\/<\/li>\n\t\t<li><strong>American Academy of Ophthalmology, &#8220;What Is Adult Strabismus?&#8221;<\/strong>: eyes not lined up; adults often see double. https:\/\/www.aao.org\/eye-health\/diseases\/what-is-strabismus<\/li>\n\t\t<li><strong>National Eye Institute, &#8220;Color blindness&#8221;<\/strong>: about 1 in 12 men have colour vision deficiency; mostly inherited. https:\/\/www.nei.nih.gov\/learn-about-eye-health\/eye-conditions-and-diseases\/color-blindness<\/li>\n\t\t<li><strong>World Health Organization fact sheet, &#8220;Blindness and vision impairment&#8221;<\/strong> (10 Feb 2026): cataract among the leading causes of blindness. https:\/\/www.who.int\/news-room\/fact-sheets\/detail\/blindness-and-visual-impairment<\/li>\n\t\t<li><strong>Definitions without a page opened in this session (standard ophthalmic definitions, to be checked by the reviewing surgeon):<\/strong> sphere, cylinder, axis, dioptre, anisometropia, accommodation, visual acuity, stereopsis, contact lens types, orthokeratology, limbus, tear film, rhodopsin, eye colour, keratitis, corneal erosion, pterygium and pinguecula, subconjunctival haemorrhage, chalazion cause, ptosis, entropion and ectropion, xanthelasma, retinitis pigmentosa, optic neuritis, Beh\u00e7et&#8217;s, ocular migraine, nystagmus, diplopia, heterochromia, exophthalmos, coloboma, photophobia, halos and glare. Search results seen for dioptre (reciprocal metre, https:\/\/en.wikipedia.org\/wiki\/Dioptre) and pterygium vs pinguecula (pterygium grows over the cornea, pinguecula does not); re-confirm against AAO\/EyeWiki on the child pages.<\/li>\n\t<\/ol><\/details><\/div><\/div><\/div><\/section>\n<!-- List (Sources and medical review) End -->\n\n\n<!-- Call to Action (Assessment band) Start -->\n<section class=\"cta-band\" id=\"assessment\">\n\t<div class=\"contact-bg\" aria-hidden=\"true\"><span><\/span><span><\/span><span><\/span><\/div>\n\t<div class=\"cta-inner pad container-fluid\"><div class=\"row\">\n\t\t<div class=\"col-12 col-lg-7\"><div class=\"cta-copy\">\n\t\t\t\t\t\t<h2 class=\"t64\" data-reveal>Found your term? Ask a surgeon about your own eyes<\/h2>\n\t\t\t\t\t\t<p class=\"t22\" data-reveal>Send your prescription, scans or eye reports. Prof. Dr. Sat\u0131c\u0131, Do\u00e7. Dr. \u00d6zer or Op. Dr. Bayram will explain what they mean for your eyes and which treatments, if any, may suit you, in writing and with no obligation.<\/p>\t\t\t\t\t\t<div class=\"cta-actions\" data-reveal><a class=\"pill pill-white\" href=\"https:\/\/laseristanbulclinic.com\/en\/free-consultation\/\"><span class=\"pill-dot\" aria-hidden=\"true\"><\/span><span class=\"pill-label\">Get my free online consultation<\/span><\/a><a class=\"pill pill-line\" href=\"https:\/\/wa.me\/4915783739465?text=Hello%20Laser%20Istanbul%20Clinic%2C%20I%20would%20like%20some%20information%20about%20eye%20treatment.%20Sent%20from%3A%20https%3A%2F%2Flaseristanbulclinic.com%2Fen%2F\" target=\"_blank\" rel=\"noopener\"><span class=\"pill-dot\" aria-hidden=\"true\"><\/span><span class=\"pill-label\">WhatsApp: +49 157 8373 9465<\/span><\/a><\/div>\n\t\t\t\t\t<\/div><\/div>\n\t\t\t\t<div class=\"col-12 col-lg-5\"><div class=\"proof-card\" data-reveal>\n\t\t\t\t\t\t<div class=\"proof-text\">\n\t\t\t\t\t\t\t\t<h3 class=\"t48\">3 eye surgeons<\/h3>\n\t\t\t\t\t\t\t\t\t\t\t\t<p class=\"t22\">Your case is reviewed by a named surgeon, not a salesperson. Reply within <span class=\"ph\">{{response time}}<\/span>.<\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t<ul class=\"avatars\" aria-label=\"Our surgeons\">\n\t\t\t\t\t\t\t\t<li><img decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/prof-dr-ahmet-satici-ophthalmologist-istanbul-150x150.webp\" class=\"attachment-thumbnail size-thumbnail\" alt=\"Prof. Dr. Ahmet Sat\u0131c\u0131\" loading=\"lazy\" srcset=\"https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/prof-dr-ahmet-satici-ophthalmologist-istanbul-150x150.webp 150w, https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/prof-dr-ahmet-satici-ophthalmologist-istanbul-300x300.webp 300w, https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/prof-dr-ahmet-satici-ophthalmologist-istanbul-768x768.webp 768w, https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/prof-dr-ahmet-satici-ophthalmologist-istanbul.webp 806w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><span class=\"tip\">Prof. Dr. Ahmet Sat\u0131c\u0131<\/span><\/li>\n\t\t\t\t\t\t\t\t<li><img decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/doc-dr-muhammet-derda-ozer-cornea-specialist-istanbul-150x150.webp\" class=\"attachment-thumbnail size-thumbnail\" alt=\"Do\u00e7. Dr. Muhammet Derda \u00d6zer\" loading=\"lazy\" \/><span class=\"tip\">Do\u00e7. Dr. Muhammet Derda \u00d6zer<\/span><\/li>\n\t\t\t\t\t\t\t\t<li><img decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/op-dr-aysan-bayram-eye-surgeon-istanbul-150x150.webp\" class=\"attachment-thumbnail size-thumbnail\" alt=\"Op. Dr. Aysan Bayram\" loading=\"lazy\" srcset=\"https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/op-dr-aysan-bayram-eye-surgeon-istanbul-150x150.webp 150w, https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/op-dr-aysan-bayram-eye-surgeon-istanbul-300x300.webp 300w, https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/op-dr-aysan-bayram-eye-surgeon-istanbul-768x768.webp 768w, https:\/\/laseristanbulclinic.com\/wp-content\/uploads\/2026\/10\/op-dr-aysan-bayram-eye-surgeon-istanbul.webp 806w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><span class=\"tip\">Op. Dr. Aysan Bayram<\/span><\/li>\n\t\t\t\t\t\t\t<\/ul>\n\t\t\t\t\t<\/div><\/div>\n\t\t\t<\/div><\/div>\n<\/section>\n<!-- Call to Action (Assessment band) End -->\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":0,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-1756","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/laseristanbulclinic.com\/en\/wp-json\/wp\/v2\/pages\/1756","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/laseristanbulclinic.com\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/laseristanbulclinic.com\/en\/wp-json\/wp\/v2\/types\/page"}],"replies":[{"embeddable":true,"href":"https:\/\/laseristanbulclinic.com\/en\/wp-json\/wp\/v2\/comments?post=1756"}],"version-history":[{"count":2,"href":"https:\/\/laseristanbulclinic.com\/en\/wp-json\/wp\/v2\/pages\/1756\/revisions"}],"predecessor-version":[{"id":2902,"href":"https:\/\/laseristanbulclinic.com\/en\/wp-json\/wp\/v2\/pages\/1756\/revisions\/2902"}],"wp:attachment":[{"href":"https:\/\/laseristanbulclinic.com\/en\/wp-json\/wp\/v2\/media?parent=1756"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}