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Ophthalmology > CORNEA
Dystrophy, Granular
Article Last Updated: Mar 15, 2006
AUTHOR AND EDITOR INFORMATION
Section 1 of 11  
Author: William Trattler, MD, Miami Center for Excellence in Eye Care; Consulting Staff, Department of Ophthalmology, Miami Baptist Hospital
William Trattler is a member of the following medical societies: American Academy of Ophthalmology
Coauthor(s):
William Lloyd Clark, MD, Consulting Staff, Palmetto Retina;
Natalie Afshari, MD, Assistant Professor, Cornea and Refractive Surgery, Department of Ophthalmology, Duke University Eye Center, Duke University Medical Center
Editors: Fernando H Murillo-Lopez, MD, Senior Surgeon, Unidad Privada de Oftalmologia CEMES; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Christopher J Rapuano, MD, Professor, Department of Ophthalmology, Jefferson Medical College; Co-Chairman of the Cornea Service, Co-Chairman of Refractive Surgery Department, Wills Eye Hospital; Lance L Brown, OD, MD, Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri; Hampton Roy Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences
Author and Editor Disclosure
Synonyms and related keywords:
granular dystrophy, corneal dystrophy, granular corneal dystrophy
Background
Granular dystrophy is an autosomal dominant, bilateral, noninflammatory condition that results in deposition of opacities in the cornea by adulthood. It specifically affects the middle portion of the cornea (stroma) and eventually can cause decreased vision and eye discomfort. Severe cases of granular dystrophy can be treated with either excimer laser ablation or by replacing cornea (corneal transplant).
Pathophysiology
The cornea is the clear outer coat of the front of eye. A dystrophy of the cornea is defined as a bilateral noninflammatory clouding of cornea. Corneal dystrophies can be divided into 3 categories based on their location within the cornea, as follows: (1) anterior corneal dystrophies affect the corneal epithelium and may involve the Bowman membrane; (2) stromal corneal dystrophies (which include granular dystrophy) affect the central layer of cornea, the stroma; and (3) posterior corneal dystrophies involve the Descemet membrane and endothelium.
Most corneal dystrophies have an onset prior to age 20 years (exceptions include map-dot-fingerprint dystrophy and Fuchs corneal dystrophy). Most corneal dystrophies are dominantly inherited, exceptions being macular dystrophy, type-3 lattice dystrophy, and the autosomal recessive form of congenital hereditary endothelial dystrophy.
Granular corneal dystrophy types I, II (Avellino dystrophy), have been reported to result from mutations in the BIGH3 gene. Depending on the specific mutation in the beta ig-h3 gene, the phenotypes of corneal dystrophy may differ.
Frequency
United States
Uncommon
International
Uncommon
Mortality/Morbidity
- Corneal changes generally first become visible during the second decade of life, but vision may not be affected until the fourth to fifth decade of life.
- Eye pain from recurrent corneal erosions also can occur.
Sex
No sexual predilection has been reported.
Age
Corneal changes usually become visible during the second decade of life, but patients may not be affected until the fourth to fifth decade of life.
History
- Patients may have decreased vision, photosensitivity, and/or eye pain (from recurrent corneal erosions).
- Because granular dystrophy is autosomal dominant, it is likely that one of the parents will have granular corneal dystrophy as well.
Physical
- Granular dystrophy is characterized by bilateral formation of discrete, focal, white granular deposits in the anterior stroma of cornea with clear areas between these deposits.
- The granules are located primarily in the central cornea, with an absence of these deposits in the peripheral cornea.
- The deposits can resemble crushed breadcrumbs or snowflakes. As patients advance in age, the deposits become larger and increase in number. Eventually, the intervening clear areas develop a mild-to-severe corneal haze.
- When there are clear spaces between the deposits, the vision generally is not affected severely. However, with time, the clear spaces become involved with opacity. This later onset opacity in the previously clear spaces is usually much more superficial than the longstanding, dense white granules. The vision declines dramatically when the clear spaces opacify.
Causes
Granular dystrophy is an autosomal dominant condition; its genetic defect has been mapped to chromosome 5q.
Dystrophy, Crystalline
Dystrophy, Lattice
Dystrophy, Macular
Dystrophy, Map-dot-fingerprint
Other Problems to be Considered
Corneal opacities
Other Tests
- Corneal biopsy (which would never be indicated clinically) would reveal eosinophilic hyaline deposits in corneal stroma. When a corneal transplant is performed, the specimen is submitted for histopathologic evaluation
- Masson trichrome stains deposits bright red.
Histologic Findings
When corneal specimens are obtained, light microscopy reveals eosinophilic hyaline deposits in the corneal stroma; the source of hyaline material is still unknown. Masson trichrome stains the deposits bright red.
Medical Care
- When recurrent erosions occur with this condition, they are treated like any other form of recurrent erosion.
- Under care of an ophthalmologist, bandage contact lens along with antibiotics can be prescribed; alternatively, patching with an antibiotic ointment can be used. Some physicians treat recurrent erosions with frequent antibiotic ointments while awake.
- Once the acute episode of recurrent erosion has resolved, preventive treatment may include sodium chloride 5% drops or artificial tear lubricating drops during the day and lubricating ointment at bedtime.
- If recurrent corneal erosions occur despite medical therapy, then excimer laser phototherapeutic keratectomy (PTK) may be considered.
Surgical Care
Excimer laser PTK is quite effective at removing opacities from the superficial cornea. When deep opacities are causing significant visual symptoms, corneal transplantation may be required.
- Excessive corneal erosions or visual decrease from superficial opacities can be treated with PTK. Excimer laser PTK removes superficial opacities, smooths the corneal surface, and allows the epithelium to re-adhere more tightly.
- If the visual acuity drops and most of the opacities are deep, lamellar or full-thickness corneal transplantation can be performed. Although the success rate for corneal transplantation is very high, granular deposits recur with time. Fortunately, when the deposits recur, they tend to be superficial, and amenable to treatment with excimer laser PTK.
Medical therapy for recurrent corneal erosions includes hypertonic saline, which is believed to increase adherence of epithelium to the underlying stroma. Lubrication, especially at bedtime, also may help prevent further corneal erosions.
Drug Category: Hypertonic saline drops
Dehydrates the epithelium, allowing it to better adhere to underlying stroma.
| Drug Name | Sodium chloride 5% (Adsorbonac, Afrin Saline Mist, Muro 128) |
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| Description | Used for temporary relief of corneal edema. |
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| Adult Dose | Solution: 1-2 gtt in affected eye(s) tid/qid
Ointment: 0.25-0.5 inch to lower cul-de-sac qhs |
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| Pediatric Dose | Administer as in adults |
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| Contraindications | Documented hypersensitivity |
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| Interactions | None reported |
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| Pregnancy | A - Safe in pregnancy
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| Precautions | May cause temporary burning and irritation upon use; if pain, change in vision, continued redness or irritation of the eye(s) occur, or if initial condition/problem worsens or persists, reevaluate therapy; do not use product if it changes color or becomes cloudy |
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Drug Category: Lubricating agents
Can moisten ocular surface and decrease frequency of recurrent erosions.
| Drug Name | Artificial tears (Celluvisc, Murine, Refresh, GenTeal, Refresh PM, Lacri-Lube) |
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| Description | Contains equivalent of 0.9% NaCl and are used to maintain ocular tonicity. Acts to stabilize and thicken precorneal tear film and prolong tear film breakup time, which occurs with dry eye states. |
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| Adult Dose | Solution: 1 gtt to affected eye 4-8 times/d
Ointment: 0.25-0.5 inch to lower cul-de-sac qhs |
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| Pediatric Dose | Administer as in adults |
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| Contraindications | Documented hypersensitivity |
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| Interactions | None reported |
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| Pregnancy | A - Safe in pregnancy
|
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| Precautions | Hyperemia, photophobia, stickiness of eyelashes, ocular discomfort or irritation may occur |
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Further Outpatient Care
- Patients with corneal epithelial defects from recurrent erosions need to be observed every few days to make certain the defect is healing.
In/Out Patient Meds
- Patients with corneal epithelial defects from recurrent erosions require treatment with topical antibiotics to prevent infection.
Complications
- Complications of granular corneal dystrophy include loss of vision and recurrent corneal erosions.
- Complications of recurrent erosions include corneal infection and scarring, which can lead to significant decreased vision.
Prognosis
- Prognosis is good, with symptomatic patients being eligible for either laser PTK or corneal transplant.
Special Concerns
- A variant of granular dystrophy is called Avellino dystrophy. Its genetic defect also has been mapped to chromosome 5q.
- In this condition, lattice deposits develop in the cornea years after typical granular deposits have developed. With age, deposits enlarge and form a corneal haze.
- Symptoms are similar to granular dystrophy, with a slightly higher chance of pain and photophobia due to recurrent corneal erosions.
- Management of Avellino dystrophy is similar to granular corneal dystrophy.
- For excessive recurrent corneal erosions or decreased vision in eyes with predominantly superficial corneal opacities, excimer laser PTK can be performed.
- For patients with vision loss after unsuccessful PTK, a corneal transplant can be performed. However, deposits eventually recur in the donor cornea.
- Children of patients with granular corneal dystrophy should be monitored once they reach puberty, because this condition has an autosomal dominant inheritance pattern.
| Media file 1:
Granular dystrophy. Image courtesy of James J Reidy, MD, FACS, Associate Professor of Ophthalmology, State University of New York, School of Medicine & Biomedical Sciences, Buffalo, New York. |
 |  View Full Size Image | |
Media type: Photo
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| Media file 2:
The slit lamp parallelipid demonstrates the deposition of opacities throughout the central stroma. |
 | View Full Size Image | |
Media type: Photo
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- Albert D, Jakobiec F. Principles and Practice of Ophthalmology. Vol 1. 1994:26-49.
- Das S, Langenbucher A, Seitz B. Excimer laser phototherapeutic keratectomy for granular and lattice corneal dystrophy: a comparative study. J Refract Surg. Nov-Dec 2005;21(6):727-31. [Medline].
- Grunauer-Kloevekorn C, Brautigam S, Wolter-Roessler M. Molecular genetic analysis of the BIGH3 gene in lattice type I (Biber-Haab-Dimmer) and granular type II (Avellino) corneal dystrophy: is indirect mutation analysis for hot spots recommended?. Klin Monatsbl Augenheilkd. Dec 2005;222(12):1017-23. [Medline].
- Klintworth GK. Advances in the molecular genetics of corneal dystrophies. Am J Ophthalmol. Dec 1999;128(6):747-54. [Medline].
- Krachmer J. Cornea. Vol 2. 1996.
- Yamamoto S, Okada M, Tsujikawa M, et al. The spectrum of beta ig-h3 gene mutations in Japanese patients with corneal dystrophy. Cornea. May 2000;19(3 Suppl):S21-3. [Medline].
Dystrophy, Granular excerpt Article Last Updated: Mar 15, 2006
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