4901 Calhoun Rd
Houston, Texas 77004

(713) 743-2020 | Monday - Friday 8AM -6PM

University Eye Institute | Our Services

Common Disorders causing vision loss (low vision)

  • congenital problems or disorders
  • traumatic injury to the eye or brain
  • systemic diseases
  • adult onset diseases
  • aging related diseases

The eye disease may cause

  • a loss of acuity (ability to see detail)
  • loss of peripheral vision or parts of the field of vision
  • constant double vision (diplopia)
  • loss of contrast sensitivity
  • reduced or loss of color vision
  • reduced or loss depth perception

These disorders and a host of other vision performance problems prevent an individual from leading a normal lifestyle performing the tasks he/she has always been able to do or would like to do. Specialized microscopic and telescopic lenses, along with other types of prescriptive magnifiers are used to allow the individual to perform simple visual tasks like reading, writing, watching TV, hobbies, performing an occupation, traveling more independently, and in some cases even driving a car. In addition to prescribed optical devices, the loss of vision can be compensated for through the use of electro-optical devices such as closed circuit television, reading machines, or heads-up display devices as found in virtual reality technology. Sometimes a significant improvement in visual performance can be realized with new medical care or simple training techniques.

Congenital vision disorders

Retinitis pigmentosa

Retinitis Pigmentosa is an inheritable condition. There are three ways that RP may be passed to family members: autosomal dominant, autosomal recessive, or X-linked inheritance. RP causes degeneration of the retina, or the back of the eye. The retina is responsible for converting light into electrical impulses that transfer messages to the brain where seeing actually occurs. Different areas of the retina contain specialized cells, called photoreceptors. There are two specific types of photoreceptors, rod and cones. These photoreceptors are responsible for different types of vision depending on their location in the retina. Peripheral vision and night vision are under control of the rods. Central vision and color discrimination are managed by the cones which are concentrated in the center, or macula, of the retina. The patient may experience difficulty in low light situations, and tunnel vision. Color discrimination may also be affected. There are other inherited retinal degenerative diseases that share some of the clinical symptoms of RP.

Albinism

Albinism is a hereditary deficiency of pigmentation, which may involve the entire body (complete albinism) or a part of the body (incomplete albinism). It is believed to be caused by an enzyme deficiency involving the metabolism of melanin during prenatal development and is typically inherited as an autosomal recessive trait. In complete albinism, there is usually lack of pigmentation in skin and hair, as well as in retinal & iris tissue. In ocular albinism, function may vary from normal to impaired and may involve the retina (especially the macula) and iris. Photophobia (sensitivity to light), nystagmus (irregular eye movements), and refractive error (near and far sightedness) are often present. If acuity is decreased, it commonly ranges between 20/70 and 20/200. The condition does not progress. The ocular symptoms of albinism are corrected with tinted or pinhole contact lenses, absorptive lenses, optical aids, and lowered illumination if needed.

Nystagmus

Congenital nystagmus is a condition with involuntary, rhythmic oscillation of eyes; may be horizontal, vertical, rotary, or a combination; fast or slow symmetric or asymmetric; pendular (equal speed in both directions) or jerk (direction designated by the fast phase component). Nystagmus is different depending on gaze; may have null point or point where it decreases. Congenital nystagmus is usually mapped to chromosome 6p. The causes of nystagmus include; achromatopsia, aniridia, blue cone monochromacy, cataract hereditary optic atrophy, high myopia, Leber's congenital amaurosis macular hypoplasia, ocular albinism, optic nerve hypoplasia, retinitis pigmentosa and rod monochromacy. Management options of congenital nystagmus include full correction of refractive error, contact lenses, base-out prism or minus lenses to stimulate convergence, yoked prism to decrease abnormal head posture, vision therapy or extraocular muscle surgery.

Traumatic vision loss

Traumatic Brain Injury

Traumatic Brain Injury may cause significant physical and functional impairments. Patients with Cerebral Vascular Accidents (Stroke) also manifest similar impairments. A person with a brain injury is very likely to have some degree of visual difficulty as the eye is a direct extension of the brain. 90% of what we perceive is through the visual system and, therefore, the rehabilitation of vision with the brain injury patient is critical to their recovery of function. Ocular diagnoses from brain injury include diplopia from cranial nerve palsies or strabismus, visual field loss, neglect, accommodation (focusing) which is inadequate, optic nerve damage, or retinal damage. The impact of the deficit may be a minor inconvenience in the patients recovery or may impair their ability to recover in many areas of life including ambulating, reading and fine motor tasks. Rehabilitation of the visual system may include partial patching, prisms, spectacles or magnifying devices. Any information gathered in regard to the patient's function is supplied to the referring physician and therapists working with the patient

Retinopathy of prematurity

Retinopathy of Prematurity (ROP) is an abnormal growth of blood vessels in the baby's eye. ROP, one of the most common causes of blindness in children today, is caused by an initial constriction and then rapid growth of blood vessels in the retina Inner lining of the eye). These new vessels grow in the wrong places, and can cause disturbances of the blood drainage pattern. When the blood vessels leak, they cause scarring. These scars later shrink, and pull on the retina, which can sometimes cause it to detach. Fortunately, in most patients with retinopathy of prematurity, the abnormal retinal vessels disappear or regress spontaneously. If the vessels continue to proliferate and place the eye at risk of retinal detachment and visual loss, treatment of the retinopathy is indicated. Treatment of ROP decreases the chances for blindness, but it does not always prevent it. It is most common in babies who are very premature, more than 12 weeks early. In development, blood vessels grow from the back central part of the eye out toward the edges.

This process is completed just a few weeks before the normal time of delivery. In premature babies this process is not complete. If blood vessel growth proceeds normally, the baby does not develop ROP. If the vessels grow and branch abnormally the baby has ROP. If your baby is at risk for ROP, your baby's eyes should be checked by an eye care specialist. These exams start at about 4-6 weeks of age and preformed regularly until the eye vessels have grown to the edges. Most treatment for ROP is done with laser photocoagulation, but other treatment modalities are sometimes used, depending upon the stage of the disease. With treatment, the inner lining of the eye at the ends of these vessels is treated to prevent further abnormal growth of the blood vessels. This helps prevent the retina from being pulled away (detached) from the outer lining by the abnormal vessels. It is important to note that certain problems are more likely to occur in eyes with regressed ROP, these include: retinal detachment, cataract, glaucoma, strabismus (wandering eye), amblyopia (lazy eye), and myopia (nearsightedness).

It is possible that in the teen years or in adulthood these individuals could experience additional vision loss and blindness. Annual eye care remains important throughout the child's life. The grade of ROP describes its severity. The eye advances through the stages, so that grade IV has already gone through grades I, II, and III. Grade I means there is a demarcation line in the retina. This indicates that the peripheral retina is not receiving a completely normal blood flow. In grade II, the line has progressed to a ridge. With both grades I and II of ROP there is a good chance for regression and normal vision for the baby. Most babies who get ROP have grades I or II. These children do well and usually have normal vision corrected with glasses. Grade III means there are abnormal blood vessels in the eye. There is scarring and fluid present as a result of the overgrowth of blood vessels. There is still some chance for regression of the abnormal blood vessels and fluid. The baby still may have good, correctable, vision. Grade IV indicates retinal detachment in response to the fluid build-up and contracting of scar tissue. This level of ROP has little chance for regression. The baby may have limited vision or blindness, depending on the degree of retinal detachment in each eye.

Vision loss due to systemic disease

Diabetic retinopathy

Diabetes mellitus affects those who are glucose intolerant and manifests in high blood glucose levels. There are two types of diabetes, Type 1 (previously known as insulin dependent) and Type 2 (previously known as non-insulin dependent). Both types of diabetes are known to affect the eye by destroying the vasculature in the conjunctiva, retina and central nervous system. Diabetic retinopathy is the result of long standing, uncontrolled systemic diabetes. Fluctuating visual acuity secondary to unstable blood sugar is a common ocular sign. Changes in the iris, crystalline lens, vitreous and retina (the optic nerve and macula) often cause severe vision loss if left untreated. Preventing diabetic retinopathy is to treat the systemic condition by controlling blood sugar levels. If it progresses to diabetic retinopathy, photocoagulation and vitrectomy may be elicited depending on the severity.

Vision disorders with adult onset

Glaucoma

Glaucoma is a group of diseases usually associated with high pressure within the eye. It can lead to progressive loss of peripheral vision and left untreated can lead to blindness. Glaucoma can be categorized as open angle, closed angle, congenital or secondary. All of these categories can cause the pressure in the eye to increase and lead to deterioration of the optic nerve. With treatment, progression of the disease can be slowed or halted. The treatment spectrum varies from topical medications to surgical intervention. Since patients do not report any symptoms until significant peripheral vision has been lost, early detection can only be attained through an examination with an eye care practitioner.

Stargardt's

Stargardt's disease (also known as fundus flavimaculatus and Stargardt's macular dystrophy) is the most common form of inherited juvenile macular degeneration(MD). Inherited as an autosomal recessive trait, it is a severe form of MD that begins in late childhood, leading to legal blindness. Stargardt's disease is symptomatically similar to age-related macular degeneration, and it affects approximately one in 10,000 children. Stargardt's disease is usually diagnosed in young individuals (less than 20 yo), when decreased central vision is first noticed. It causes a progressive loss of central vision and, in the early stages, patients may have good visual acuity, but they may experience difficulty with reading and seeing in dim lighting. Other common symptoms of Stargardt's disease include blurriness and distortion.

On examination, the ophthalmological findings vary significantly with the progression of the disease. In fundus photos, patients with early Stargardt's disease appear to have simple macular degeneration. Children with the disease typically begin experiencing problems adapting to dark environments and central vision loss between six and twelve years of age, but symptoms may also first appear in adulthood. Currently, there is no effective treatment for Stargardt's disease, but having the genetic code,"instruction manual", may assist in developing new strategies for therapy. It is also important that the learning and working environment be adapted for people with Stargardt's disease. Appropriate low vision aids and lighting are two important considerations for helping both children and adults to function as normally as possible.

Optic Atrophy

Optic atrophy is a degeneration of the optic nerve fibers which sends visual information from the retina to the brain. This condition can lead to a loss of clarity, changes in the field of vision or both. Optic atrophy can arise from a considerable number of causes. Ocular disease can contribute to atrophy of the optic nerve or the disease may be hereditary. Other possible causes include injury to the eye, various types of inflammation or brain tumor, meningitis, poison or drugs, and hydrocephalus. The patient may experience slight blurring to serious sight loss affecting one or both eyes. Although currently there is no cure, the condition usually stabilizes. Functional vision can be enhanced with magnification and other low vision devices.

Vision loss due to age-related causes

Age-related macular degeneration

Macular degeneration, often called AMD or ARMD (for age-related macular degeneration), is the leading cause of blindness in the world affecting as many as 15 million Americans and millions more around the world. The disease attacks the macula of the eye, where our sharpest central vision occurs. Macular degeneration varies widely in severity. Although it rarely causes total blindness, age-related macular degeneration robs those affected of their sharp central vision and can dim contrast sensitivity and color perception. It destroys the clear, "straight ahead" central vision necessary for reading, driving, identifying faces, watching television, doing fine detailed work, safely navigating stairs and performing other daily tasks we take for granted. Peripheral vision may not be affected, and it is possible to see "out of the corner of your eye".

The impact of developing AMD can be devastating to those who were independent and active prior to the onset of this impairment. Their visual world gradually diminishes into a vague blur, making ordinary daily activities challenging. Macular degeneration is diagnosed as either dry (atrophic) or wet (exudative). The dry form is more common than the wet, with about 90% of AMD patients diagnosed with dry AMD. The wet form of the disease usually leads to more serious vision loss it may respond to laser procedures, if diagnosed and treated early. Some common symptoms are a gradual loss of ability to see objects clearly, distorted vision, a gradual loss of color vision and a dark or empty area appearing in the center of vision. If you experience any of these, contact your eye care professional immediately for a comprehensive examination. Central vision that is lost to macular degeneration cannot be restored. However, low vision devices such as telescopic and microscopic lenses can be prescribed to make the best use of the remaining vision. Recent research indicates certain vitamins and minerals may help prevent or slow the progression of macular degeneration.