Galactose and cataract

Galactosemia is a disorder caused by a deficiency of any one of three possible enzymes involved in the metabolism of galactose: galactokinase, transferase or epimerase. Any single deficient enzyme can result in cataract through the accumulation of galactitol in the lens. The ophthalmologist may play an important role in this disease, since early recognition of cataract development followed by the initiation of a galactose-free diet may lead to clearing of lenticular opacities. The clinical and laboratory findings that distinguish the three enzyme deficiency disorders of galactosemia are discussed. The biochemical genetics of each enzyme also are reviewed, along with the recent evidence linking heterozygous galactokinase deficiency and presenile cataract.     

Comparison of corneal deposits after LASIK and PRK in eyes with granular corneal dystrophy type II

PURPOSE: To compare the characteristics of corneal deposits in eyes with granular corneal dystrophy type II (Avellino corneal dystrophy) after LASIK and photorefractive keratectomy (PRK). METHODS: Patients with heterozygous granular corneal dystrophy type II were examined with slit-lamp microscopy for recurrence of granular corneal dystrophy type II after uneventful LASIK and PRK surgery. One particular case involved bilateral incomplete flaps after LASIK, resulting in excimer laser ablation under the flap in one area and surface ablation in another area of both eyes. Deoxyribonucleic acid sequencing analysis in all patients confirmed the heterozygous status of granular corneal dystrophy type II. RESULTS: An abundance of coarse, white opacities consistent with granular corneal dystrophy type II were observed along the interface in all of the LASIK cases. In comparison, only a mild increase in opacities was noted in the PRK cases. In the LASIK case with bilateral incomplete flaps, abundant opacities were present in both corneas along the interface of the LASIK flap, and a minimal increase of stromal opacities was noted where no LASIK flap was present. CONCLUSIONS: Exacerbation of granular corneal dystrophy type II deposits occurred in the corneal stroma to a much greater degree after LASIK compared to surface ablation surgery.     

Avellino corneal dystrophy after LASIK

OBJECTIVE: To report cases of Avellino corneal dystrophy (ACD) exacerbated by LASIK for myopia. DESIGN: Retrospective, noncomparative, interventional case series and review of the literature. PARTICIPANTS: Seven patients. INTERVENTION: Six patients with exacerbation of granular corneal deposits after LASIK were examined for TGFBI mutations by polymerase chain reaction sequencing of DNA. One previously reported patient who was heterozygous for the ACD gene was followed up for 16 months after mechanical removal of granular deposits from the interface after LASIK. MAIN OUTCOME MEASURES: Slit-lamp examination, visual acuity, manifest refraction, and DNA sequencing analysis. RESULTS: All patients were heterozygous for the Avellino dystrophy gene. Corneal opacities appeared 12 months or more after LASIK. Best spectacle-corrected visual acuity decreased as the number and density of the opacities increased. One patient underwent mechanical removal of granules from the interface and had a severe recurrence within 16 months. Another patient had removal of the granules from the interface with PTK, followed by treatment with topical mitomycin C. In this patient, the cornea has remained relatively clear for 6 months. CONCLUSIONS: Laser in situ keratomileusis increases the deposition of visually significant corneal opacities and is contraindicated in patients with ACD. Mechanical removal of the material from the interface does not prevent further visually significant deposits. Mitomycin C treatment, in conjunction with surgical removal of opacities, may be an effective treatment.     

Clinical and ultrastructural classification of Reis-Bückler corneal dystrophy

Reis-Bücklers' corneal dystrophy has been incorrectly defined in the English literature: the corneal opacities described in most reports on it do not correspond to Bücklers' original findings, but are equivalent to Thiel and Behnke's honeycomb corneal dystrophy. Moreover, the synonym "annular dystrophy" is based on a misunderstanding and ought to be replaced by the term "maplike dystrophy". Perhaps due to the misnomer, annular or honeycomblike subepithelial opacities have come to be regarded as Reis-Bücklers' dystrophy. Subsequently, histologic and ultra-structural features were also evolved from such supposed cases, and the curly, electron-dense filaments were regarded as pathognomonic. The erroneous definition in the standard literature has been causing diagnostic confusion ever since. Research in the older literature and studies of the author's own patients have established the following original features of Reis-Bücklers' dystrophy: (1) dominant inheritance, (2) early manifestation and rapid progression, (3) painful attacks during childhood, (4) subepithelial corneal opacities extending almost to the limbus, (5) maplike opacity pattern, (6) sheetlike deposits replacing Bowman's membrane in histologic sections, (7) electron-dense rod-shaped bodies observed by electron microscopy. The original Reis-Bücklers' dystrophy resembles granular corneal dystrophy (Groenouw I) histochemically and ultrastructurally, but differs from it in its clinical symptoms, corneal opacity pattern, histopathological arrangement, and probably gene linkage as well. The condition commonly referred to as Reis-Bücklers' dystrophy in the literature is in fact Thiel and Behnke's honeycomb corneal dystrophy.     

An unusual clinical phenotype of Avellino corneal dystrophy associated with an Arg124His beta iG-H3 mutation in an African-American woman

PURPOSE: To describe the clinical features, histologic changes, and genetic analysis of Avellino corneal dystrophy in an African-American woman. DESIGN: Interventional case report. METHODS: A 79-year-old African-American woman with corneal deposits consistent with Avellino corneal dystrophy was studied with histologic and genetic analysis. RESULTS: The patient had multiple crumb-like opacities in the anterior stroma of both eyes. Deep to these lesions were numerous faint, stellate lattice lesions. Corneal scraping confirmed the presence of Masson trichrome and Congo red positive subepithelial deposits. Genetic analysis revealed a heterozygous CGC/CAC change in exon 4 of the beta iG-H3 gene, resulting in an arginine to histidine substitution at codon 124. CONCLUSIONS: This case reveals several novel findings, including surface changes resembling vortex dystrophy and large granular deposits protruding through the anterior corneal surface. This is the first case described in an African-American patient.     

Multiple excimer laser phototherapeutic keratectomies for Avellino corneal dystrophy: a case report

Dear Editor,I am Chihiro Koiwa,from the Department of Ophthalmology,Juntendo University Hospital.I am writing this letter to present a case of multiple excimer laser phototherapeutic keratectomies(PTKs)for Avellino corneal dystrophy(ACD).Corneal dystrophy is a common type of hereditary,noninflammatory,and bilateral corneal disorder that involves various pathological,histological,and clinical manifestations[1].Advanced molecular gene sequencing has identified specific mutations that are associated with most dystrophies of this type.ACD,also known as granular corneal dystrophy typeⅡ[2],is autosomal dominant and associated with the R124H mutation of the transforming growth factor beta-induced(TGFBI)gene and characterized by deposits consistent with both discrete granular and lattice corneal opacities[3-4].An analysis of the TGFBI gene is essential to differentiate ACD because heterozygous R124H mutation carriers have minimal corneal abnormalities,whereas homozygotes have severe visual impairment,starting from early childhood,and early postoperative recurrence of corneal opacity.     

Epithelial corneal basement membrane dystrophy

Dystrophy of the basement membrane of the corneal epithelium is an autosomal-dominant disease. Three distinct forms of opacity occur, either in isolation or in combination with one another. These are (1) dotlike opacities, (2) maplike opacities and (3) fingerprint lines. The present paper describes a family in which 6 members show only the characteristic signs of superficial maplike corneal opacities. There have been no recurrent corneal erosions. In addition, 7 "isolated cases" are described in which both the pure and combined forms of opacity have been observed. The dotlike opacities are demonstrable only when maplike alterations are also present. The patholomechanism leading to these dotlike changes cannot be explained by aberrance of the basement membrane alone. Cases of the three forms of opacity which may occur as secondary phenomena have to be distinguished from the dystrophic form.     

Glutathione and NADP linked enzymes in human senile cataract

Oxidized and reduced free glutathione were measured in clear and cataractous human lenses. Total glutathione decreases with the course of cataract. There exists a clear difference between different types of cataract. Lenses showing biomicrosopically superficial opacities as well as total opaque lenses contain only small levels of reduced glutathione whereas the level of the oxidized glutathione seems to be less changed. Since the enzyme activities of glutathione reductase and of enzymes linked to hydrogen producing pathways show only slight alterations, except in the mature cataract, the differences of the glutathione content in the various types of cataract may not be explained by the deficiency of enzyme activities. It is assumed that a loss of the reduced glutathione in human lenses occurs under two perhaps independent conditions: (1) the presence of a large amount of opaque lens material (for example nuclear cataract); (2) the occurrence of a superficial destruction of the lens even if the lens is nearly clear (for example subcapsular cataracts). There seems to exist a connection between the reduced glutathione level in the lens and a cation shift.     

Xerophthalmia and anterior-segment blindness among preschool-age children in El Salvador.

A countrywide prevalence survey of 9,508 children was conducted in El Salvador to determine the prevalence of anterior-segment abnormalities and magnitude of clinical vitamin A deficiency. Thirty-six children had corneal opacities, 56% of them secondary to trauma. Such traumatic corneal opacities were 19 times more frequent among urban than rural children, 57.6 vs. 3.1 per 1,000. Keratomalacia accounted for only 8% of all corneal opacities, and for one (and possibly two) of the five cases of bilateral anterior-segment blindness encountered. The prevalance of Bitot spots and vitamin-A-related corneal opacities was 5.3 and 3.2 per 10,000, respectively. There are an estimated 43 new surviving cases of vitamin-A-related corneal opacities in the country each year, one third of which result in bilateral blindness. Fifteen percent of all children examined had grossly purulent conjunctivitis.     

Oligosymptomatic cornea verticillata in a heterozygote for Fabry disease: a novel mutation in the alpha-galactosidase gene

BACKGROUND: Fabry disease is an X-linked genetic disorder involving sphingolipid catabolism, which is caused by lysosomal alpha-galactosidase A deficiency. Ophthalmological findings such as corneal and lens opacities and conjunctival and retinal vessel abnormalities can be the only and/or the first recognizable symptoms, especially in heterozygous females. METHODS: We report on a 34-year-old German woman with cornea verticillata. The alpha-galactosidase A activity was determined in leukocytes using a fluorescence substrate, and the sequence analysis of the alpha galactosidase A gene was performed with genomic DNA. RESULTS: The alpha-galactosidase A activity in leukocytes was significantly low (0.24 nmol/min/mg protein; normal range, 0.4-1.2), which is compatible with a heterozygote for Fabry disease. The following sequence analysis revealed a heterozygous transition in position IVS5 + 2 T > C. Transition of thymine (T) to cytosine (C) affects the donor splice motive of exon 5 and most probably leads to an aberrant splicing procedure of the alpha-galactosidase A gene. CONCLUSION: Our case emphasizes the importance of ophthalmological findings in Fabry disease. The subsequent biochemical and molecular analysis provides a secure diagnosis of female carriers of Fabry disease.     

Confocal microscopy in a case of crystalline keratopathy in a patient with smouldering multiple myeloma

We report the clinical and confocal microscopic findings of the cornea in a patient with smouldering multiple myeloma (SMM) using in vivo scanning laser confocal microscopy. A 72-year-old female underwent a complete ophthalmological examination including slit-lamp biomicroscopy with digital photography, HRT II laser scanning in vivo confocal microscopy and haematological laboratory assessment. Corneal biomicroscopy revealed the presence of bilateral diffuse microgranular tiny grey opacities. In vivo confocal microscopy showed randomly oriented hyper-reflective needle-shaped crystals throughout all levels of the stroma, sparing epithelium and endothelium. In vivo confocal microscopy was very helpful in the differential diagnosis by allowing the nature of the corneal deposits to be established, revealing the typical aspect of the crystals, and excluding granular dystrophy, leading to a suspected diagnosis of SMM. Crystalline corneal deposits may easily be confused as crumb-like opacities typical of granular dystrophy on slit-lamp examination even by experienced ophthalmologists.     

Reis-Bückler's dystrophy

Summary A case of Reis-Bückler's dystrophy in a 36-year-old man is reported. Its clinical aspect is compared with its histological and ultrastructural features. The slight reticular opacities situated superficially in the central part of the cornea, immediately beneath the epithelium, correspond to dark, irregular deposits. These replaced the basal membrane and Bowman's membrane and are composed of granular material, glycogen granules, and short fibers. These short, curved, osmiophilic fibers whose diameter is approximately 130 Å are also located inside the anterior stromal lamellae. These deposits seem to be the characteristic feature of this particular and rare dystrophy, stated as by Hogan. Their nature and origin are discussed.This paper was presented in part at the Sixth Annual Meeting of the European Club for Ophthalmic Fine Structure in Paris, France on March 31 and April 1, 1978     

Surgical do's and don'ts of corneal dystrophies

PURPOSE OF REVIEW: Characteristics of corneal dystrophies have been described with regards to such as location in the cornea, morphology, material composition, and recurrence after penetrating keratoplasty. The main goal of this review is to describe the surgical methods in treating corneal dystrophies. RECENT FINDINGS: Laser in situ keratomileusis (LASIK) has been shown to aggravate corneal deposits in Avellino dystrophy exacerbation LASIK and hence should be avoided. Phototherapeutic keratectomy (PTK) has shown its usefulness in clearing opacities with visual improvement and prevents painful erosion, resulting in delay or postponement of corneal grafting in some corneal dystrophies. Mitomycin-C may be used topically in conjunction with PTK to reduce the recurrence of the opacities. Topical use of antibody to TGF-beta can also be considered to suppress recurrence of corneal opacities after PTK or lamellar keratectomy. SUMMARY: Clinicians must become more adept at choosing a treatment depending on different genotypes and future studies on treatment of corneal dystrophies should be focused on establishing treatment of categorized corneal dystrophies based on their chromosomal mutation.     

Exacerbation of Avellino corneal dystrophy after LASIK in North America

PURPOSE: To report the first case of Avellino corneal dystrophy exacerbation after LASIK in a white or North American patient. METHODS: Case report and literature review. RESULTS: A 25-year-old white female developed progressive corneal opacities after LASIK. Preoperative examination had revealed only subtle white corneal opacities in each eye. The patient's mother had similar corneal opacities. DNA analysis of the patient revealed a heterozygous mutation at the R124H location in the BIGH3 gene. CONCLUSIONS: LASIK can exacerbate Avellino corneal dystrophy and should be avoided in patients with this condition. A careful history and genetic analysis can identify affected patients and those at risk.     

Electrolytic removal of recurrence of granular corneal dystrophy

AIMS: To report the efficacy of corneal electrolysis for the treatment of recurrent corneal opacities at the subepithelial region or at the host-graft interface of the stroma in granular corneal dystrophy (GCD). METHODS: In patients with recurrences of opacities at the host-graft interface of the stroma after lamellar keratoplasty, the deep aspect of the graft was partially separated from host tissue to expose the deposits. The graft was everted, and electrolysis was applied directly to remove the deposits attached to both surfaces of the host and the graft. Then the graft was returned to its place and sutured. In patients with diffuse subepithelial opacities following penetrating keratoplasty, electrolysis was applied directly to the corneal surface. RESULTS: Deposits in the subepithelial region or at the host-graft interface of the stroma disappeared following treatment, and vision recovered. However, GCD recurred 2-3 years after the treatment. CONCLUSIONS: Corneal electrolysis is a simple, easy, and inexpensive way to remove deposits that recur after lamellar or penetrating keratoplasty for GCD.     

Late occurrence of granular dystrophy in bilateral keratoconus: penetrating keratoplasty and long-term follow-up

We report a rare case of keratoconus with granular dystrophy with a follow-up of two decades, documenting the sequential presentation of two diseases confirmed by histology and genetic studies. A 13-year-old boy was diagnosed in 1988 with keratoconus in both eyes (BE) based on slit-lamp biomicroscopy findings of corneal ectasia in BE accompanied by Fleischer's ring, Vogt's striae, a small, old, healed hydrops. The left eye (LE) had central corneal thinning and scar in the central area involving the mid and posterior stroma secondary to healed hydrops. Penetrating keratoplasty (PKP) was advised. The boy was lost to follow-up till 1991 and presented with white, dot-like opacities in the central cornea in the RE only, suggestive of granular corneal dystrophy. Similar findings of white, dot-like opacities were noted in the LE in 1995 and the patient subsequently underwent PKP in BE. Histopathology of corneal buttons confirmed the presence of patchy, crystal-like orange deposits, which stained bright red with Masson's trichrome. Mutational analysis of the TGFBI gene in patient's DNA revealed a heterozygous mutation corresponding to a change in Arg555Trp in the keratoepithelin protein. Granular dystrophy recurred after 8 years in the RE.     

Corneal opacification and lecithin-cholesterol acyltransferase (LCAT) deficiency: a case report

Bilateral corneal opacities are the first clinical sign of a familial lecithin-cholesterol acyltransferase (LCAT) deficiency and can be found in early childhood. Familial LCAT deficiency includes the following typical clinical findings: corneal opacification, proteinuria, anemia, turbid or milky plasma, very low plasma HDL, very low plasma cholesterol esters and lysolecithin, hyperlipidemia, and very low or absent LCAT enzymatic activity. Several patients have had fundus findings including angioid streaks and papilledema. This disease is autosomal recessive and has been reported in a total of 19 patients previously. Progression of the disease has resulted in premature atherosclerosis, renal failure and transplantation, decreasing visual acuity and corneal transplantation.     

Mutation P28T in gene GK1 as the cause of a familial galactokinase deficiency

OBJECTIVE/METHOD: To alert about galactokinase deficiency (GK) as a possible cause of infantile cataracts, and even presenile cataracts in heterozygous carriers. Diagnosis by enzyme and galactitol determination would lead to the introduction of a galactose-free diet which completely prevents the damage. RESULT/CONCLUSIONS: We report on a highly consanguineous Spanish family of gypsy ethnia, with three females of different sibships affected by GK deficiency. The deficiency was due to their homozygosis for mutation P28T in gene GK1. P28T mutation in european Romani gypsies, is also present in Spanish gypsies. It is important to bear in mind that GK deficiency may be an important cause of blindness in that endogamous group.     

Two mutations in the transforming growth factor beta-induced gene associated with familial Lattice corneal dystrophy

AIM: To report a phenotypic variant pedigree of lattice corneal dystrophy (LCD) associated with two mutations, R124C and A546D, in the transforming growth factor beta-induced gene (TGFBI). METHODS: A detailed ocular examination was taken for all participants of a LCD family. Peripheral blood leukocytes from each participant were extracted to obtain the DNA. Polymerase chain reaction (PCR) of all seventeen exons of TGFBI gene was performed. The products were sequenced and analyzed. Histological examination was carried out after a penetrating keratoplasty from the right eye of proband. RESULTS: Genetic analysis showed that the proband and all 6 affected individuals harbored both a heterozygous CGC to TGC mutation at codon 124 and a heterozygous GCC to GAC mutation at codon 546 of TGFBI. None of the 100 control subjects and unaffected family members was positive for these two mutations. Ocular examination displayed multiple refractile lattice-like opacities in anterior stroma of the central cornea and small granular deposits in the peripheral cornea. The deposits were stained positively with Congo red indicating be amyloid in nature and situated mainly in the anterior and middle stroma. CONCLUSION: We observed a novel LCD family which carried two pathogenic mutations (R124C and A546D) in the TGFBI gene. The phenotypic features were apparently different from those associated with corresponding single mutations. The result reveals that although the definite mutation is the most important genetic cause of the disease, some different modifier alleles may influence the phenotype.