| uman eye is a complex, biological mechanism that | | | | vision. These hands-on models, which are three to |
| allows us to interact with the visible world in | | | | five times larger than a real eye, can be |
| every enterprise from working on a computer to | | | | disassembled to show the various parts of the |
| driving a car or threading a needle. Without sight, | | | | eye and their functions, and are especially useful |
| we would be little more than slugs. Yet most | | | | with children, whose natural curiosity engages a |
| people take sight for granted; until something | | | | respect for vision and a greater tendency to |
| happens to make them question this everyday | | | | wear the eyeglasses prescribed. |
| miracle. | | | | Eye models are also useful for explaining surgical |
| The human eye is not, however, perfect. Defects | | | | interventions that can improve eyesight or |
| in the size or shape of the cornea, lens, vitreous | | | | prevent further deterioration, especially to the old, |
| humor (the fluid space within the eye), macula | | | | whose memory and concentration may be |
| (the focal point), optic nerve or muscles can | | | | further affected by the inability to hear properly. |
| cause us to see imperfectly. These defects are | | | | An eighty-year-old person will understand macular |
| classed as myopia (nearsightedness), hyperopia | | | | degeneration, or diabetic retinopathy, a hundred |
| (farsightedness), presbyopia (aging eye) or | | | | times better by seeing a disassembled model of |
| astigmatism, where an irregularly-shaped cornea, | | | | an eye than by simply listening to an eye surgeon |
| on one or both eyes, causes blurred vision. | | | | describe what can be done to improve vision. |
| The most common problems with vision occur as | | | | For medical education purposes, a 20-centimeter, |
| we age, and can include cataracts (a clouding of | | | | eight-part model of the eye showing the upper |
| the lens), age-related macular degeneration, or | | | | half of the sclera with corneal and eye muscle |
| AMD, a degeneration of the macula, glaucoma | | | | attachments, which subdivides into two halves |
| (caused by an increase in pressure in the vitreous | | | | showing the choroid with its attendant iris and |
| humor which distorts vision), and diabetic | | | | retina, as well as the lens, vitreous humor, eyelid |
| retinopathy, which results from damage to the | | | | and tear duct system, will provide a wealth of |
| blood vessels that feed the retina. Models of the | | | | teaching example prior to actual dissection by a |
| human eye can help explain these conditions and | | | | medical student, or deliver a concise yet definitive |
| diseases to patients and other physicians to help | | | | explanation to mature patients on the intricate |
| everyone understand how the eyes are affected. | | | | workings of the eye. Seven-part models are also |
| Using larger-than-scale models of the eye, | | | | available, in three- or five-times magnifications. |
| ophthalmologists can demonstrate to patients | | | | Some models are available on bases, and all are |
| how, and where, these vision defects occur. This | | | | manufactured of durable plastic compounds with |
| is useful not only for making healthy vision | | | | full-color didactics, and sealed against humidity and |
| recommendations like safety goggles and | | | | body oils to last for years, even with extensive |
| anti-glare monitor screens, but also for prescribing | | | | handling. |
| corrective lenses or contacts to correct faulty | | | | |