Have you ever eaten “with your eyes”? The chances are yes. Apart from odor and taste, the sight of food contributes significantly to our assessment and enjoyment of food. In fact, the glamourised appearance of a particular food item often becomes the single most powerful advertisement, especially on social media, to the extent that it becomes commonly called food pornography. As such, eating with our eyes is certainly a true fact, underlining the importance of our sense of sight in the quality of life.
But have you ever thought of eating “for your eyes”?
Eating to see well follows universal dietary principles, which are to have a varied, broad-based diet and preferably fresh food from uncontaminated sources. In addition to this, several unique food apply to visual health. I would divide them into two categories, broadly-speaking: eating for the health of the front of eye and the back of eye.
Firstly, the front of eye. The ocular surface comprising the cornea and conjunctiva is what meets the environment. The cornea, a transparent tissue, permits light through, and provides structural integrity to the front of our eyes, while the conjunctiva is the lining of the white of our eyes. These are usually protected by a thin layer of fluid called the tear film, which can dry out when blinking rate drops due to prolonged visual attention.
Modern, desk-bound lifestyle sees many of us glued to computer screens and for way toolong. The consequence of that is an increase in what is termed “digital eye strain”, which causes tired eyes and sometimes, blurring of vision due to dryness and exposure. Coping mechanisms are none other than reducing the duration of near work and taking frequent visual breaks. Dietary supplements in the form of omega-three fatty acids, either fish oil or plant-based in origin, are commonly prescribed for dry eyes syndrome. Simplified, they work in a two-pronged way: strengthening the external oily layer of the tear film to prevent early evaporation of the tear, and also to improve the health of the oil glands at the lid margin, a vital part of our eye surface. These supplements are, in my experience, truly helpful for low to moderate grades of dry eyes, and are generally very safe to be consumed long term. They are available over the counter in most pharmacies, with several formulae produced specifically for dry eyes, even though generic formulae are often just as effective. .
From my understanding, the amount of these fatty acids acquired from modern day regular meals are usually insufficient, and there are no issues in taking supplements in the form of capsules for these. I occasionally suggest oil forms of these supplements, added to salads or soups. I routinely recommend these supplements to my cataract and LASIK patients, who usually will encounter a short duration of dry eyes post-operation. However, severe grades of dry eyes should also be treated medically with prescription eyedrops.
Eye problems arising from nutritional deficiency such as night blindness and xerophthalmia (very severe dry eyes) from severe lack of Vitamin A are very rarely encountered nowadays due to the improved diet in our society. There is some evidence that adequate Vitamin C from natural food sources has protective effects against cataract formation.
For the back of eye, the central area of the retina called the macula is where photoreceptors are the most concentrated and hence the most sensitive area of our retina. The macula is the site of insult of two common eye diseases: diabetic retinopathy and age-related macula degeneration. This area, when affected by these diseases, may swell up, bleed internally and collect deposits of waste substances. The damage caused to sight can be grave, as central vision and reading are affected. Other than the macula, the rest of the retina may also be affected by diabetes.
Dietary guidelines for diabetic eye disease sufferers are identical to other diabetes sufferers. Studies have, however, shown that a tight control of blood glucose level helps to maintain vision, as the tiny blood vessels of the retina succumb easily to poor diabetes control, resulting in sprouting of new and fragile blood vessels that bleed and scar, causing retina detachment and blindness in the advanced stages.
Often, a visit to a dietitian helps to plan a diabetic diet. A diet composed of regular meals to prevent extreme blood sugar swings is the aim, while keeping intake of calories and body weight in check is definitely a plus. Further attention to types of carbohydrate consumed may also result in maintaining an even keel.
As for age-related macular degeneration, a disease affecting the elderly in which the macula area is affected by deposits of waste material which result in abnormal blood vessels, the link between diet and vision is much studied. These studies showed that a regular intake of lutein and zeaxanthin (carotenoids, or pigments found in naturally colourful food), zinc and vitamin A, C and E can reduce the incidence of disease and reduce the risk of disease progression by up to 25 percent. The dietary recommendations resulting from the oft-quoted large-scale Age-Related Eye Disease Study 2 (AREDS2) form the basis of several oral supplements for macula health, available fairly readily over the counter and in most specialist eye clinics. For natural sources of lutein and zeaxanthin, look no further than the usual colourful fruits and vegetables, including kale, spinach, papaya, blueberries, goji berries and peppers. These colourful foods help to maintain colourful vision.
Care in avoiding the wrong food can also bode well for our sight. Infrequent reports of severe blindness from toxicity to the optic nerves, due to accidental ingestion of methanol are still encountered in the region, even in Singapore. Possible ocular side effects of medications such as steroids and some oral drugs for cardiac and rheumatoid diseases should also be monitored by the eye specialist, to prevent vision impairment.
Healthy eyes and vision are some of the best gifts in life. Why not repay our eyes the enjoyment we derive from it, by eating right for our sight?
Have a date with our Specialists at 360 Health Management Seminar on 30 Mar 2019, Saturday 10am to 2pm at SPH News Centre Auditorium. Our Specialists will be sharing various health issues that you might be facing. Register online at 360health19.sphevents.com.sg
Dr. Daphne Han
Senior Consultant, Ophthalmologist
Singapore Medical Specialists Centre
The Business Times, Sunday, 2 March 2019