New SoClear Lens is So Clear

We have been using a new gas permeable rigid lens called the SoClear lens. It is a scleral lens, which means it has a very large diameter = 13.0 to 15.0 mm. These large diameter rigid lenses work very well for patients with corneal dystrophies such as Keratoconus and pellucid marginal degeneration. The lens completely vaults the cornea and rests on the white of the eye (sclera). Patients with irregular corneas who have had problems in the past with contact lenses find these lenses work almost miraculously well.

These large lenses are a bit time consuming to fit because multiple diagnostic lenses must be applied to the eyes to determine the proper lens fit. The "bowl" of the lens must be filled with saline and orange dye (fluorescein) to evaluate the lens/cornea relationship. Patients with irregular corneas almost always have normal peripheral corneas/ scleras, and these lenses "fit" on that area of the eye. Sceleral contact lenses such as SoClear are the best bet for providing good vision on irregular corneas.

You Can’t Hide From the B-scan

It is fairly common to encounter patients with dense cataracts that do not allow the doctor a very good view of the posterior structures of the eye. These structures include the optic nerve and retina. In our office we use the ScanMate Ultrasound B-unit from DGH to better evaluate the retina and optic nerve when we cannot directly view these structures with standard exam techniques.

Retinal detachments are easily picked up with the B-scan. This instrument is invaluable when the doctor cannot get a good peripheral view of the retina due to cataracts.

Even when the view of posterior eye structures is unimpeded, B-scan can come in handy. Buried drusen in the optic nerve can cause visual field loss. A B-scan can confirm that what appears to be buried drusen really is, and not a more serious optic nerve problem.

The B-scan experience is very comfortable for the patient. We obtain data through a closed eye, so no “goopy stuff” needs to be applied to the open eye when using the probe to obtain an image.

Not - So - Peripheral Vision

At my office, we do a visual field screening test with almost every standard eye examination. This is sometimes incorrectly referred to as a “peripheral vision test”. My Humphrey-Zeiss automated visual fields tester can measure the visual field out to the far periphery, but during the screening mode it only tests the central 30° of the visual field. The vast majority of the neurological disorders we are looking for will be picked up in this 30° central test.

Two main disorders we are looking for are brain tumors and strokes. Both of these disorders can cause a visual field loss because they disrupt the “wiring” in the visual pathway in the brain. The visual cortex, or “seeing” part of the brain, is located at the very back of the cranium. The “wires” in the visual pathway that connect the retina in the eyes to the visual cortex travel through the parietal and temporal lobes of the brain. The “wires” responsible for the left half of our visual field travel in the right side of the brain, and those for the right half of the visual field travel in the left side of the brain. Therefore, any disruption of the wires (from, say, a stroke or a tumor) on the left side of the brain can cause a visual field loss on the right. Problems on the right side of the brain will manifest in the left half of the visual field. When visual fields are screened, careful attention is paid looking for field loss present in both eyes symmetrically on either the left or right half of the field.

It's Good to Be Thick (In Some Places):

Eye pressure is nearly always measured during a comprehensive eye examination. It is an important measurement because high fluid pressure in the eye can cause the gradual death of the optic nerve. This disease process often leads to visual field loss and sometimes central acuity loss, and is known as glaucoma. Other risk factors exist for glaucoma other than high eye pressure. One important risk factor is central corneal thickness.

When eye pressure is measured, the cornea is flattened (applanated) from its normal convex shape to a flat (Plano) state. This flattening is achieved with a puff of air (non-contact tonometry) or with a probe (Goldmann tonometry). The amount of force required to flatten (applanat) the cornea is measured and converted to a fluid pressure in millimeters of mercury. Typical normal eye pressure runs from 8 to 21 millimeters of mercury. When the cornea is flattened, the calculations used to convert the force required to flatten it to fluid pressure, assume that the cornea is “average” thickness. Average is about 550 microns thick centrally.

I was taught in optometry school 30 years ago that almost all corneas are average thickness. We now know that this is not true. Since thin corneas are a contraindication for some refractive surgeries (i.e. LASIK), many practioners have ultrasound–A units that measure central corneal thickness quickly and easily. In my office, use of my ultrasound–A unit (pachymeter) has shown a wide variance among patient’s corneal thickness. It is not unusual to see thick corners (580 microns and higher) or thin corneas (520 microns and lower). Since it is easier to flatten a thin cornea, most experts’ feel that a patients true eye pressure is actually higher than that measured if the patient has a thin cornea. Patients with thick corneas probably have lower pressure than that measured.

Thin corneas are an independent risk factor for glaucoma. Irrespective of a patient’s true pressure, the theory goes that patients with thin corneas probably have other structures in the eye that are thinner than normal, which may be more easily damaged by fluid pressure. I always tell patients it’s good to be thick in some places. The cornea is definitely one of those places.

A Goji Berry a Day Keeps the Cataract Doctor Away

There are only two protective pigments in the human lens and retina -Lutein and Zeaxanthin. These two are both yellow pigments. Research indicates that of the two pigments, Zeaxanthin is more important. In the macula (central retina) Zeaxanthin is found at a 2 to 1 ratio to Lutein centrally. Lutein is at a 2 to 1 ratio to Zeaxanthin in the less important peripheral macula. Both Lutein and Zeaxanthin protect the lens from cataract formation.

The P.O.L.A. study published in 2006 indicted that high levels of both Lutein and Zeaxanthin in the diet protect the macula from age-related macular degeneration. Only high levels of Zeaxanthin in the diet however, were shown to protect the lens from cataracts.

Zeaxanthin is less common than Lutein in foods we typically eat. A small amount of Zeaxanthin is found in green leafy vegetables such as kale, spinach, broccoli, and mustard and collard greens. A bit more is found in egg yolks. A better source of Zeaxanthin is found in orange (not green) peppers. The best source of Zeaxanthin in nature is goji berries (also known as wolf berries). These can be purchased in dried form and resemble dried cranberries in taste and appearance.

Since Zeaxanthin is an important protective yellow pigment for the eye, and is sometimes difficult to get in a normal diet, taking it in supplement form makes sense. At Dr. Steven Lutz and Associates, we recommend and sell EyePromise daily eye supplement, which contains 8mg of Zeaxanthin and EyePromise Z-10 which has 10mg Zeaxanthin in pure olive oil. Both supplements cost about 50 cents a day.

Digital Retinal Imaging is Superior

We have utilized digital retinal imaging at Dr. Steven Lutz and Associates, in Ann Arbor Michigan, for about six years. This technology makes viewing the central retina of the eye with high resolution a breeze. Digital retinal imaging is far superior to standard ophthalmoscopy examination technique when evaluating the central retina.

My retinal camera is the Zeiss Visucam. The superb German optics in this unit produces the finest retinal images available anywhere. When evaluating the retinal images in the exam room we utilize high resolution LCD flat screens. The doctor can show the patients their retina on the screen, and can better explain any areas of concern. The imaging system has a zoom feature, allowing the doctor to highly magnify any central retinal area he or she wishes to evaluate more closely. This zoom feature is a key advantage of digital systems over manual ophthalmoscopy.

Age – related macular degeneration (AMD) is a main cause of vision loss in older adults. The earliest signs of AMD are subtle pigmentary changes (and subtle white drusen in the central retina macula). I have found that these subtle pigmentary changes are much easier to see with digital imaging versus standard exam techniques.

Glaucoma - More Than Just Eye Pressure

During a comprehensive eye examination, it is customary to measure eye pressure. This pressure is called intra-ocular pressure (I.O.P.). Many patients dread the air- puff tonometry test, and refer to it as a “glaucoma test”. This is technically not correct, since eye pressure is only one component of a glaucoma diagnosis. In fact, it is possible for a patient to have normal eye pressure, but still have glaucoma. Glaucoma is the (usually) slow death of the optic nerve fiber layer (N.F.L.) usually, but not always, caused by high pressure.

In glaucoma, as the nerve layer slowly dies, it becomes thinner. A scanning laser, such as the Zeiss GDX or the Zeiss OCT, can measure this N.F.L. thickness. These lasers also compare patient results to a data base of people with the patient’s same age and race. These units also perform statistical analysis, showing the doctor how significant a particular deviation in N.F.L. thickness is from a normative data base.

At Dr. Steven Lutz and Associates, we measure eye pressure with both air-puff tonometry and Goldmann aplanation tonometry. We also utilize a Zeiss GDX scanning laser to better help us diagnose and treat glaucoma.