Frequently Asked Questions

What are those little black spots and lines that I see especially in bright light? Are they dangerous? What are those lightning like flashes that I occasionally see in the sides of my visual field?

Those are called floaters by your eye doctor. Most of the cavity of the eye is filled with a gel-like substance called the vitreous gel. These floaters are clumps of vitreous collagen meshwork that have formed as a result of liquefaction of the vitreous gel, a physiologic process called syneresis. When we are young, the vitreous is a gel that has an invisible meshwork- like structure. When we age the gel liquefies. At age 50 years of age, 60% of us already have liquefaction of the vitreous, either partially or complete. When this happens the collagen meshwork collapses and forms little clumps that now become big enough to cast shadows on our retina. We see them as black or gray dots, patches, lines that move upwards and downwards, and left and right as if floating in our field of vision.

As a general rule these are not ominous signs as they occur as part of the aging process. In certain situations however, they can be dangerous. Occasionally people with vitreous floaters have retinal thinning called lattice, retinal breaks or tears and holes that must be treated right away with focal laser to prevent retinal detachment. Occasionally the floaters are actually red blood cells and clumps of vitreous hemorrhage. The hemorrhage is due to the avulsion of retinal blood vessels that are pulled by the collapse of the vitreous meshwork and separation of the posterior vitreous cortex from the retina.

Flashes are extremely bright lightning like streaks of light seen in the periphery of ones visual field. They are caused by stimulation of the retina by pulling of the posterior vitreous cortex on the retina to which it is attached. They are actually similar to hallucinations since they are generated by the brain, as responses of the retina to the physical stimulation of pulling or traction.

Although usually harmless, it is best to see an Ophthalmologist (eyeMD) if you experience floaters or flashes just to make sure they are not signs of more serious conditions of the retina.

How does diabetes mellitus affect the eye? Will good blood sugar control reverse the bad effects of diabetes on my eye?

Diabetes is a potentially blinding disease. It causes diabetic retinopathy which happens as a result of poor blood circulation and therefore inadequate oxygen supply. Diabetic retinopathy is a retinal disease that results in retinal hemorrhages, ischemic patches and abnormalities in the retinal blood vessels. Abnormal vessel growth eventually leads to massive bleeding and/or traction membrane growth, and eventually traction retinal detachment. The major risk factors are the duration of diabetes, level of blood sugar control, concomitant hypertension and pregnancy. The longer the patient has diabetes, the more he is at risk of developing the disease. By the 15th year of diabetes mellitus, 80 % of diabetics have the lower stages of diabetic retinopathy and approximately 20% already have the blinding stages of the disease.

Good blood sugar control has been proven to reduce the chance of developing diabetic retinopathy or its progression by about 30%. If a patient already has diabetic retinopathy, control of blood sugar will neither reverse the process nor reduce the damage already done to the retina. Any treatments instituted, both to the eyes and the diabetes, including laser treatment to the eyes, blood sugar and blood pressure control are aimed at preventing progression to the higher stages of retinopathy.

The pregnant diabetic patient deserves special attention as progression of the disease can be aggravated by the pregnancy.

Diabetes can also cause affectation of the optic nerve, a condition called diabetic papillopathy. Eye muscle problems (deviation of the eyeball) can also be caused by diabetes mellitus as it can affect the nerve supply of the eye muscles. Cataracts can also be aggravated by diabetes mellitus.

If I eat plenty of carrots and yellow foods will my retina be stronger and more resistant to retinal disease?

The eye and the retina certainly need vitamins. While eating carrots and yellow veggies and foodstuffs rich in vitamin A can help one get this vitamin from natural sources, the eye and retina in particular need more than just vitamin A but also vitamin E and C, zinc and selenium as well. These are called antioxidants. Instead of taking vitamin A supplements alone, it would be better to take a vitamin preparation with A, C, E, selenium and zinc. These are marketed as antioxidants.

Antioxidants remove free radicals from our system and help spare retinal cells (and other body cells) from oxidative damage, and make metabolism more efficient. In this way they are good for not only for our eyes but for our entire body.

Taking these vitamins will not stop myopia and myopic degenerative disease of the retina. In the right amounts (the AREDS formula) antioxidants have been shown to be effective for Age Related Macular Degeneration. Your ophthalmologist can prescribe the anti-oxidant preparation for you.

Will a baby’s prematurity cause blindness? What can be done to prevent blindness from Retinopathy of Prematurity?

Not all prematurity results in blindness. A premature baby of a certain weight and birth age, defined as high risk, is open to the development of the disease during the first few weeks of life outside the womb. The definition of high risk is a birthweight of 1500 grams and below, and age at birth of 32 weeks and below. Only 15% of high risk babies actually develop some form/stage of the disease, but only 5-6% of these go into the severely visually debilitating stages. Fortunately only about 1% of all high risk premature babies actually develop blinding disease.

Prematurity is the greatest risk factor. The smaller the baby, and the more premature it is, the greater is the risk. Other risk factors are exposure to oxygen and the associated systemic problems after birth. Blood transfusions, infection, respiratory distress, etc, are definite negative factors that can increase risk and must be taken into consideration.

When a baby fits into the high risk criteria, the retina must be screened by an ophthalmologist who will perform a dilated fundus examination. This means that drops will be instilled onto the baby’s eyes to dilate the pupil temporarily to allow the ophthalmologist to examine the retina. Babies that are found to have some form of the disease will require serial examinations and/or actual management. When the fundus findings fit the description of threshold disease, treatment in the form of laser or cryopexy must be instituted. Sometimes prethreshold treatment may be justified. Higher stages called ROP 4 A & B and ROP 5 will need vitreoretinal surgery which is a more invasive and delicate procedure.

The visual prognosis for ROP 4 B is guarded, and is very bad for ROP 5.

Will I eventually become blind or poorly sighted later in life because of my nearsightedness?

Those who have high myopia or nearsightedness of 6 Diopters (600 in common language) may have myopic retinal changes that have the potential to cause loss of vision of variable degrees. However, not everyone who is highly myopic has these problems. These myopic changes are collectively referred to as myopic degeneration. They come in the form of thinning of the peripheral retina (lattice degeneration), retinal tears and holes, staphylomatous changes (abnormal out-pouching) of the back of the eye, abnormal vessels under the macula (choroidal neovascular membranes), thinning of the retinal pigment epithelium.

When there are lattice lesions, retinal tears and holes, retinal detachment can occur, causing sudden drop in vision. A retinal detachment is a separation of retina from the underlying retinal pigment epithelium and accumulation of fluid in the space. Retinal detachment will need surgery to close this retinal tear or hole to reattach the detached retina. Visual prognosis is always guarded, and vison is almost always subnormal compared to fellow eye in spite of successful surgical reattachment.

Another cause of visial loss in high myopes is the growth of a submacular neovascular membrane. In this case there is a submacular hemorrhage and atrophy and scarring at the macula, the center of vision. When this happens the patient loses only central vision, not peripheral vision. These cases are managed with special pharmacologic and laser treatments. The eventual scar formation results in central visual loss of variable degrees.

Thinning of the layers of the retina at the posterior pole (back portion of the eye) causes loss of vision of varying degrees, depending on the tissue loss and scarring. There is no treatment for this problem.

Again, not everyone who is highly myopic will have these problems. And, patients who have myopic degenerative changes may have all of these at the same time, combinations of these, or perhaps only one.



Dr. David F. Chan

Ano ang diabetic retinopathy? What is diabetic retinopathy?

"Diabetic retinopathy" ang tawag sa pagkasira ng retina, ang balat sa loob ng ating mata, dala ng paglason nito ng mataas an asukal sa dugo o blood sugar.  Dalawa ang kadalasan nitong kategorya.  Una ay ang "diabetic macular edema," kung saan may naiipong manas sa gitnang parte ng retina na responsable sa karamihan ng ating paningin, ang macula.  Tumatagas ang mala-tubig na parte ng ating dugo dala ng pangit at magaslaw na takbo ng dugo dito.  Ang pangalawa ay ang pagtubo ng panibagong mga ugat ng dugo sa retina.  Sa kasamaang palad, itong pagsubok ng mata na buhayin muli ang sariling sirkulasyon ay nakakasama.  Tumatagas at maselan ang mga ugat na ito, at may karugtong pa itong mga sapot, "membrane," o "scaffold" na nakakakulubot at punit ng retina.  Ang mismong magaslaw na takbo ng dugo ay nakakadulot din ng sari-saring ibang sakit, kasama na ang malawakang pagbara ng blood supply o "retinal occlusion."  Kahalintulad nito ang "stroke" sa utak or "heart attack," na sa mata naman naganap.

Diabetic retinopathy refers to destructive changes in the retina brought about by toxic effects of elevated blood sugar.  It usually comes in one of two forms.  Frequently, they occur simultaneously.  The first is the accumulation of fluid in the area responsible for central vision, the macula.  This is termed (diabetic) macular edema.  The second is the growth of abnormal new fibrous tissue/membranes and blood vessels.  These new blood vessels are a faulty, insufficient compensation for the poor blood supply.  Additionally, they grow on a scaffold of membranes which can pull on or tear the retina.  This can also cause bleeding in the central cavity of the eye.  Abnormalties of blood flow and supply can also lead to other disease entities, such as sudden, widespread blockages in the form of retinal occlusions.

Ano ang sintomas ng diabetic retinopathy? What are the symptoms of diabetic retinopathy?

Nagmumula ang ating paningin sa maayos na pagtanggap ng ilaw ng ating mga retinal cells.  Bumubuo ang ating retinal cells ng mensahe o "signal" base sa ilaw na pumapasok sa mata, at pinapadala ito sa utak upang pumasok sa kamalayan natin ang "nakikita" ng mata.  Ang anumang pinsala sa retina, samakatuwid, ay magdudulot ng sari-saring abnormal na paningin na may pagkapareho sa ibang sakit sa mata:

  • bawas na detalye sa mga nakikita
  • pagbabaluktot ng paningin
  • pakiramdam na may nagtatakip ng paningin
  • lumulutang na itim

 Mahalagang maalala na maaaring maganda pa ang paningin ng isang taong may diabetes, ngunit may diabetic retinopathy na siya na magagamot!  Ang anumang diagnosis ng diabetes ay dahilan upang maeksamen ang mata/retina.  Maaaring mas lalo itong kailangan kapag ang isang may diabetes ay makapansin ng anumang pagbabago sa paningin.

We can see because light is received and transmitted by our retinal cells.  Any disease of the retina can result in altered vision common to many other eye diseases. 

  • decreased details
  • distortion
  • curtain-like vision loss/darkening
  • floating dark spots

Notably however, a diabetic can have good vision even if treatable, earlier stages of retinopathy are already present!  Any diagnosis of diabetes is thus a valid reason to have an eye/retina exam.  Vision changes in a person with diabetes may make the need for a consultation more urgent.

Paano nakakabulag ang diabetic retinopathy? How does diabetic retinopathy cause decreased vision or blindness?

Ang anumang pinsala o "stress" sa retina ay nakakasira sa mga cells ng retina o "photoreceptors."  Ang pangit na blood supply o manas/"edema," ay nakakabawas sa sustansya ng mga ito at magdulot sa dahan-dahan nitong paglagas/pagkamatay.  Walang kirot ang prosesong ito.  Kung may nalagot na ugat ng dugo at magkalat ang dugo sa loob ng mata, maaari nitong harangin ang ilaw papunta sa retina.  Hindi gumagana ang punit at naka-alsa na retina.  Minsan pa'y sumasabay ang glaucoma at katarata sa tuwing may sakit ng diabetes sa mata.

Any stress on the retina destroys the cells for vision, our photoreceptors.  Poor blood supply, or edema, can deprive cells of nutrition leading to painless cell death.  Blood in the vitreous can block light from reaching the retina.  Torn, detached retina does not function and thus causes vision loss.  Glaucoma and cataract may accompany diabetic eye disease.

Anong pwedeng gawin para maiwasan ito? What can be done to avoid these?

Ang pag-iwas sa mismong diabetes ang pangunahing hakbang para maiwas ang lahat ng ito.  Sa mga may diabetes na, hindi naman katiyakan ang pagkakaroon ng retinopathy.  May pag-uulat mula sa sari-saring mga bansa sa Asya na aabot ng 36.8% ang kaganapan ng retinopathy sa mga may Type 2 diabetes.  Mas malala ito sa mga Kanluraning bansa (Europa at Amerika), pati sa mga may Type 1 o "juvenile" diabetes.  May mga lugar na higit 90% ang retinopathy sa ganitong mga kaso.  Maaga at tuluyang pagkontrol ng diabetes ang susi sa pag-iwas sa retinopathy, kapag nahatulang may diabetes.  Mahalaga ring maalala na ang buntis na may diabetes ay maaari ring makaranas ng matinding retinopathy.  Ang pagbantay sa kanilang paningin, tuwing at lalo kung may diabetes, ay mahalaga rin.

Ang bilis at dalas ng paglala ng retinopathy ay magkakaiba rin.  May paggamot upang labanan ito, na siya namang mas matagumpay kung maaga ang pagtuklas ng sakit.  Ang payo ng doktor sa schedule ng follow-up check-up ay nakatuon sa maagang pagtuklas at paggamot sa retinopathy.  Mahalaga ito upang maiwasan ang malalang sakit na madalas mas mahirap at magastos gamutin.

Diabetes prevention is the best measure to avoid these pathologies.  While worse diabetes brings higher risk for retinopathy, it does not occur 100% of the time.  In different Asian countries, studies report prevalence of retinopathy in Type 2 diabetics as high as 36.8%.  It is higher in Western countries and among juvenile/Type 1 diabetics.  In some countries, retinopathy has been observed in up to 90+% of them.  Early and sustained control is thus key, given a diagnosis of diabetes.  Diabetes in the pregnant can be severe and rapidly-progressing.  Monitoring of their eyes/vision, especially in the setting of diabetes, is also important.

Progression/worsening rates vary as well.  Therapies exist to prevent progression/worsening.  The key is early enough diagnosis.  Evidence-based follow-up schedules have been developed, appropriate to the severity of retinopathy.  Being faithful to this follow-up schedule with your ophthalmologist will lower your chances of developing advanced, difficult-to-treat retinopathy.

Ano ang kadalasang ginagawa para sa may mga diabetic retinopathy? How is diabetic retinopathy usually treated?

Bukod sa laging pagpapaalala sa pagkontrol ng blood sugar, may sari-saring mga test/laboratory na maaring imungkahi para mas kumpleto ang pag-unawa sa retinopathy.  Kabilang dito ang paglitrato, pagsuri sa sirkulasyon ng retina (angiography, gamit ang dye na fluorescein), o "CT scan" ng mata gamit ang "OCT" (optical coherence tomography).  Maaaring magrekmoenda ng mga partikular na laser at pag-inject ng ilang klaseng gamot sa mata.  Ilan sa mga paggamot na ito ay para sa pagkontra sa paglala ng retinopathy, habang ang iba ay kokontra sa nakapanlalabong manas/macular edema.  Minsan, mabagal at matagal ang pag-igi ng retinopathy, at mangangailangan ng ilang buwan o taon ng pagbantay, testing, at pagpagamot.  Upang ayon sa tamang pag-unawa, inaasahan, at kagustuhan ang gamutan, mahalaga ang maayos na komunikasyon at pakikipagtambalan sa iyong retina specialist.

Aside from advising good blood sugar control, ophthalmologists can recommend different kinds of tests to better understand the severity and extent of your disease.  Photographs, blood vessel studies (angiography with fluorescein dye) or an eye "CT" scan or "OCT" (optical coherence tomography) may be done to document and track diseased areas.  Varied laser treatment and medicines injected into the eye may be recommended.  Some treatments prevent advanced retinopathy from occurring while others treat vision-impairing macular edema.  At times, the disease can be less receptive to treatment, requiring many months/years of repeated treatment, monitoring, and testing.  Communication and partnership with your retina specialist will be important so that your treatment will abide by clear expectations and your wishes.


National Eye Institute (United States of America) 2015, "Facts About Diabetic Eye Disease,"  NEI, accessed 26 March 2019 <>

The Mayo Clinic 2018, "Diabetic retinopathy," accessed 26 March 2019 <>

Tidy C, Jackson C.  2017  "Diabetic Retinopathy." accessed 26 March 2019 <>

American Optometric Association. undated. "Diabetic Retinopathy" AOA, accessed 26 March 2019 <>

Lee R, Wong TY et al.  Epidemiology of diabetic retinopathy, diabetic macular edema and related vision loss. Eye Vis (Lond). 2015; 2: 17.