Unilateral Granular Type 2 Corneal Dystrophy With Exacerbation After LASIK

PURPOSE

The aim of this study was to report a case of unilateral granular corneal dystrophy type 2 (GCD2) with exacerbation after bilateral laser in situ keratomileusis (LASIK).

METHODS

Clinical evaluation, Scheimpflug imaging, anterior segment optical coherence tomography (AS-OCT), cytology, and genetic testing were used to confirm the diagnosis of unilateral GCD2 with exacerbation after bilateral LASIK. Detailed literature review for possible unilateral GCD2 presentations was performed.

RESULTS

A 54-year-old White woman presented with blurred vision in her left eye and a history of bilateral LASIK performed 8 years before. Examination revealed dense opacities in the left cornea only, which were confirmed to be confined to the LASIK interface and adjacent corneal stromal tissue, as determined by AS-OCT. The patient underwent flap lift, interface debris removal, and stromal bed phototherapeutic keratectomy. Cytological analysis showed eosinophilic corneal stromal deposits that stained with trichrome stain and were congophilic on Congo red stain. Genetic testing was positive for heterozygous GCD2 transforming growth factor β-induced gene ( TGFBI ), c.371G>A, p.R124H mutation. There were no opacities identifiable in the right eye on serial slit-lamp examination, Scheimpflug imaging, or OCT imaging at 4 or 8 years after bilateral LASIK. Literature review failed to identify any previous reports of unilateral GCD2.

CONCLUSIONS

This is the first known reported case of unilateral granular corneal dystrophy type 2. LASIK is contraindicated in eyes with corneal stromal dystrophies related to mutations in TGFBI as both flap creation and laser ablation can exacerbate visually significant opacity formation. Scheimpflug and AS-OCT imaging are useful to identify opacities in GCD2.

Neurotrophic Keratopathy After Slow Coagulation Transscleral Cyclophotocoagulation

PURPOSE

Decreased corneal sensation and subsequent neurotrophic keratopathy (NK) is an uncommon complication after transscleral cyclophotocoagulation (TSCPC). Post-TSCPC NK has been rarely reported in the literature, predominantly after traditional, "pop technique" continuous-wave TSCPC or micropulse CPC. The authors report the first case series of NK after slow-coagulation TSCPC (SC-TSCPC).

METHODS

This was a respective chart review of patients who developed NK after SC-TSCPC. The collected data included demographic data, type of glaucoma, risk factors for corneal anesthesia in addition to the number of laser spots, and the extent of the treated area.

RESULTS

Four eyes experienced NK after SC-TSCPC. The median time for the development of NK was 4 weeks. At the final visit, 2 patients had a resolution of NK, 1 had a persistent corneal ulcer, and 1 had worsening NK and corneal perforation.

CONCLUSIONS

NK is a rare but a vision-threatening complication that can develop after SC-TSCPC in patients with risk factors for decreased corneal sensation. Early diagnosis and proper management are crucial to reducing the risk of vision loss and improving the prognosis of these cases.

Concomitant Bandage Contact Lens, Oral Nicergoline, and Topical Autologous Serum for Severe Neurotrophic Keratitis

BACKGROUND

To report the outcomes of using the combination of oral nicergoline, autologous serum, and contact lens to enhance corneal epithelization in neurotrophic keratitis and to discuss the clinical potential of this management.

METHODS

This was a prospective consecutive case series study of eight patients treated for neurotrophic keratitis at the "Conde de Valenciana" Institute of Ophthalmology. Oral nicergoline, autologous serum, and bandage contact lens were initiated at the same time, immediately after stage 3 diagnosis keratitis was confirmed clinically, and until corneal epithelialization was achieved or eminent corneal perforation was seen. In patients where diabetes was a cause, glycosylate hemoglobin was measured to asses metabolic control. Corneal esthesiometry and corrected distance visual acuity were assessed before and after treatment.

RESULTS

This study included eight eyes of eight patients (5 men [62.5%], average age 57±17.9 years). All patients completed at least 1 month of follow-up after nicergoline and contact lens suspension. Of the eight eyes, no one had positive culture growth and complete epithelial healing was achieved in all cases. Half of patients had diabetes and had a poor metabolic control. Corneal sensitivity improved in all eyes almost 2 centimeters in Cochet-Bonnet esthesiometry ( P= 0.01). In addition, final visual acuity gains were obtained ( P= 0.100).

CONCLUSIONS

The combination of oral nicergoline, autologous serum, and bandage contact lens simultaneously could be an alternative in the management of stage 3 neurotrophic keratitis when conventional medical treatment has no improvement of corneal epithelization.

Corneal Electrolysis for Granular Corneal Dystrophy Type 2 (Avellino Corneal Dystrophy) Exacerbation After LASIK

PURPOSE

To report two cases in which exacerbation of granular corneal dystrophy type 2 (GCD2; Avellino corneal dystrophy) after laser in situ keratomileusis (LASIK) was successfully removed by corneal electrolysis.

METHODS

This study involved a 66-year-old man and a 43-year-old man with GCD2 who had undergone bilateral LASIK for myopia 10 or more years prior to presentation. In both patients, GCD2 corneal opacity gradually developed postoperatively at the LASIK flap interface, thus resulting in a decrease of visual acuity. For treatment, the LASIK flaps in both patients were surgically lifted to directly remove the opacity. Corneal electrolysis was then applied to the back of each LASIK flap and stromal bed.

RESULTS

Postoperatively, the ocular symptoms and corneal opacities related to GCD exacerbation disappeared, with improvement of corrected and uncorrected distance visual acuity and almost no change of refractive error.

CONCLUSIONS

The findings reveal that corneal electrolysis is safe and effective for treating exacerbations of GCD2 following LASIK when applied to a surgically lifted flap, and that it successfully removes GCD2-related LASIK flap interface opacities with almost no change of refractive error postoperatively. [J Refract Surg. 2023;39(1):61-65.].

Recurrence of Avellino Corneal Dystrophy Following Penetrating Keratoplasty: A Case Report

Granular - lattice (Avellino) corneal dystrophy is inherited in an autosomal dominant fashion which affects stroma of the cornea with recurrent erosions and decreased vision due to clouding of cornea in later stage. We reported a case of 53-year old woman presented with pain and blurring of vision of left eye for 10 days with history of right eye deep anterior lamellar dystrophy and Left eye penetrating keratoplasty 5years back for Avellino dystrophy. On examination right eye graft was clear and left eye showed circular edges of irregular epithelium with patchy stains and epithelial defect suggestive of recurrence of dystrophy. A patient with recurrent corneal erosions and opacity in cornea has to be examined carefully so as not to overlook Avellino corneal dystrophy. Being a rare disorder this case has been reported to draw the attention of ophthalmologists about its recurrence following keratoplasty.

Customized Ablation Area PTK as a Technique for Salzmann's Degeneration and Other Focal Stromal Pathologies

PURPOSE

To introduce a customized ablation area photo-therapeutic keratectomy (PTK) technique that uses a preoperatively generated laser ablation profile to accurately match and ablate the area of the pathology.

METHODS

A case of mid-peripheral Salzmann's nodular degeneration causing recurrent epithelial erosion is described. The white-to-white distance, on a slit-lamp image of the patient's eye, was measured by a Placido and dual-Scheimpflug analyzer and used as a scale on a Java-based image processing program to extrapolate the focal corneal pathology's vertical and horizontal dimensions on the corneal plane. The lesion's depth was measured by corneal optical coherence tomography (OCT). Customized ablation area transepithelial PTK, tailored to the exact dimensions of the pathology was then performed in one pass, regionally ablating the area of the pathology only.

RESULTS

Complete epithelial healing was observed by the next day with unaltered visual acuity of 20/20. Corneal OCT performed at 1 and 3 months postoperatively showed near-complete resolution of the lesion. The patient was followed up for a total of 6 months with no reported symptoms of corneal erosions.

CONCLUSIONS

The application of a customized laser ablation area in the treatment of Salzmann's nodular degeneration and other focal stromal pathologies avoids unnecessary epithelial and stromal ablation. This contributes to faster visual recovery and less refractive impact, especially for peripheral lesions. [J Refract Surg. 2020;36(5):340-344.].

DIFFUSE CHORIORETINAL ATROPHY IN CHINESE HIGH MYOPIA: The ZOC-BHVI High Myopia Cohort Study

PURPOSE

To explore the associations between diffuse chorioretinal atrophy (DCA) and age, sex, axial length, spherical equivalent, and best-corrected visual acuity (BCVA) among highly myopic eyes.

METHODS

This study included right eyes of 857 bilaterally highly myopic individuals from the ZOC-BHVI Cohort Study. Participants underwent examinations, including BCVA, ocular biometry, autorefraction, and color fundus photography. An Early Treatment Diabetic Retinopathy Study grid was applied on the fundus photographs to evaluate the location of DCA, which was graded into four categories (D0-D3). The characteristics and ocular biometry were compared between participants' eyes with and without DCA.

RESULTS

Diffuse chorioretinal atrophy was found in 177 (20.6%) eyes. The proportion of participants with DCA in age groups of 7 to 11, 12 to 18, 19 to 39, and ≥ 40 years old was 20.9%, 9.2%, 23.1%, and 52.9%, respectively. The proportion of DCA significantly increased with longer axial length and worse myopic spherical equivalent. Eyes with DCA had poorer BCVA (Snellen visual acuity 20/36, logarithm of minimal angle of resolution 0.26 ± 0.25) than those without DCA (Snellen visual acuity 20/23, logarithm of minimal angle of resolution 0.06 ± 0.14) (P < 0.001). The BCVA gradually declined as the lesion got closer to the fovea (P for trend < 0.001).

CONCLUSION

The proportion of DCA increased with older age, longer axial length, and more myopic spherical equivalent. Diffuse chorioretinal atrophy is a vision-threatening complication of high myopia where BCVA gradually worsens with foveal involvement.

Salzmann's nodular degeneration of cornea associated with thyroid eye disease

Salzmann's nodular degeneration (SND) typically occurs in patients who are female, 50-60 years old, and have a history of corneal inflammation and irritation. Multiple case reports have documented associations between SND and trachoma, viral infections, trauma, contact lens wear, corneal surgeries and corneal exposure. The authors describe a patient with bilateral SND confirmed by anterior segment optical coherence tomography (OCT) imaging in the context of thyroid eye disease (TED) and history of LASIK. Treatment involved propylthiouracil (PTU), artificial tear use, loteprednol etabonate ophthalmic gel, eyelid taping and selenium supplementation and prospective superficial keratectomy with diamond burr polish.

Long-term Clinical Outcomes of Phototherapeutic Keratectomy in Corneas With Granular Corneal Dystrophy Type 2 Exacerbated After LASIK

PURPOSE

To investigate the long-term clinical outcomes and recurrence patterns of phototherapeutic keratectomy (PTK) in patients with granular corneal dystrophy type 2 (GCD2) exacerbated after LASIK.

METHODS

Fifty-one patients (76 eyes) with GCD2 exacerbated after LASIK who underwent PTK between January 2007 and February 2017 were included. Participants underwent ophthalmic examination, including slit-lamp microscopy, corrected distance visual acuity (CDVA), slit-lamp photography, and Fourier domain optical coherence tomography at preoperative and postoperative visits. PTK was performed using VISX S4 IR (VISX, Inc., Santa Clara, CA). Visual acuity, complications, interval, and contributing factors of recurrence were evaluated.

RESULTS

The follow-up period ranged from 1 to 108 months (mean: 35.22 months). The mean logMAR CDVA was 0.55 ± 0.43 (Snellen equivalent 20/80) preoperatively and 0.09 ± 0.43 (Snellen equivalent 20/25) at 3 months postoperatively. Forty-five (61.6%) eyes developed biomicroscopic recurrence at a mean of 18.6 months after PTK; 20 (27.4%) eyes developed significant recurrence at a mean of 31.3 months after PTK. The flap removal group demonstrated better CDVA at 3 years after surgery and lower recurrence and complication rates than the flap conservation group. Multivariate analysis revealed that flap removal remarkably reduced the risk of both any sign of and significant recurrence.

CONCLUSIONS

PTK improved corneal transparency and visual acuity in patients with GCD2 exacerbated after LASIK, although GCD2 eventually recurred. PTK with flap removal was superior to PTK with flap conservation in terms of visual acuity, recurrence, and complications. [J Refract Surg. 2018;34(2):132-139.].

Defect in phosphoinositide signalling through a homozygous variant in PLCB3 causes a new form of spondylometaphyseal dysplasia with corneal dystrophy

BACKGROUND

Bone dysplasias are a large group of disorders affecting the growth and structure of the skeletal system.

METHODS

In the present study, we report the clinical and molecular delineation of a new form of syndromic autosomal recessive spondylometaphyseal dysplasia (SMD) in two Emirati first cousins. They displayed postnatal growth deficiency causing profound limb shortening with proximal and distal segments involvement, narrow chest, radiological abnormalities involving the spine, pelvis and metaphyses, corneal clouding and intellectual disability. Whole genome homozygosity mapping localised the genetic cause to 11q12.1-q13.1, a region spanning 19.32 Mb with ~490 genes. Using whole exome sequencing, we identified four novel homozygous variants within the shared block of homozygosity. Pathogenic variants in genes involved in phospholipid metabolism, such as PLCB4 and PCYT1A, are known to cause bone dysplasia with or without eye anomalies, which led us to select PLCB3 as a strong candidate. This gene encodes phospholipase C β 3, an enzyme that converts phosphatidylinositol 4,5 bisphosphate (PIP2) to inositol 1,4,5 triphosphate (IP3) and diacylglycerol.

RESULTS

The identified variant (c.2632G>T) substitutes a serine for a highly conserved alanine within the Ha2' element of the proximal C-terminal domain. This disrupts binding of the Ha2' element to the catalytic core and destabilises PLCB3. Here we show that this hypomorphic variant leads to elevated levels of PIP2 in patient fibroblasts, causing disorganisation of the F-actin cytoskeleton.

CONCLUSIONS

Our results connect a homozygous loss of function variant in PLCB3 with a new SMD associated with corneal dystrophy and developmental delay (SMDCD).

[Analysis of TGFBI gene mutation in a Chinese family affected with Reis-Bucklers corneal dystrophy]

OBJECTIVE

To analyze the clinical features and TGFBI gene mutation in a Chinese family affected with Reis-Bucklers corneal dystrophy.

METHODS

Genomic DNA was extracted from 53 members including 9 patients from the family. The 17 exons and splice region of introns of the TGFBI gene were amplified by PCR and directly sequenced. All family members were subjected to ophthalmologic examination.

RESULTS

A heterozygous mutation (R124L) was found in exon 4 of the TGFBI gene among all patients from the family. The same mutation was not found among unaffected family members. The inheritance pattern of the family was identified as autosomal dominant, and the Reis-Bucklers corneal dystrophy in the family was diagnosed as the geographic type.

CONCLUSION

The R124L mutation of the TGFBI gene probably underlies the pathogenesis of Reis-Bucklers corneal dystrophy in this Chinese family. Molecular genetic approach is useful for the proper diagnosis of this type of corneal dystrophy.

Retinal vascular nonperfusion in siblings with Dandy-Walker variant

We report the case of a 2-month-old girl with Dandy-Walker variant who presented with strabismus, pathologic myopia measuring -16.00 D in each eye, diffuse chorioretinal atrophy and pigment mottling in the macula of both eyes, and areas of retinal capillary nonperfusion in both eyes. The patient's brother also has Dandy-Walker variant and was found to have bilateral severe myopia, myopic fundi, tilted optic disks with peripapillary atrophy, extensive areas of white without pressure, areas of lattice degeneration, and several chronic-appearing atrophic retinal holes surrounded by pigmentation. We hypothesize that children with Dandy-Walker variant may present with refractive errors such as pathologic myopia and with diverse retinal findings, including retinal ischemia. A lower threshold for ophthalmologic examination may be considered in this population.

[Lattice degeneration of the retina]

Lattice degeneration of the retina is a clinically important type of peripheral retinal dystrophies due to its participation in the pathogenesis of rhegmatogenous retinal detachment. In spite of extensive epidemiological, morphological, and clinical data, the question on causes of this particular type of retinal dystrophies currently remains debatable. Existing hypotheses on pathogenesis of retinal structural changes in lattice degeneration explain it to a certain extent. In clinical ophthalmology it is necessary to pay close attention to this kind of degenerations and distinguish between cases requiring preventive treatment and those requiring monitoring.

Unilateral posterior polymorphous corneal dystrophy associated with ipsilateral anisometropic amblyopia

Posterior polymorphous corneal dystrophy is typically considered asymptomatic unless visual opacity develops. However, some have suggested that asymmetric disease without visual opacity might be associated with asymmetric refractive error, which would have the potential to be the cause of amblyopia in young children. In support of this concept, a case of unilateral posterior polymorphous dystrophy with ipsilateral anisometropic amblyopia is reported.

Epithelial marker expression in Salzmann nodular degeneration shows characteristics of limbal transient amplifying cells and alludes to an involvement of the epithelium in its pathogenesis

PURPOSE

To look at the epithelial nature of Salzmann nodular degeneration (SND) and its possible relation with the aetiology of the subepithelial collagen deposition.

METHODS

Histological slides of 28 patients with SND were analysed for limbal and central corneal epithelial markers. Expression pattern of these markers in the basal layer of the epithelium was analysed and compared to the expression pattern in central corneal and limbal epithelium. Statistical analysis was performed by means of analysis of variance.

RESULTS

Expression of the epithelial stem cell marker ABCG2 and p63 was low in SND. Expression of CK12, a marker for terminally differentiated epithelium, was low, as well. But, CK19 and Enolase-alpha expressions were significantly increased and resembled the expression pattern of transient amplifying cells (TAC) of the limbus.

CONCLUSION

The epithelium in SND shows similar characteristics as TAC of the limbus and seems to be metabolically more active than the differentiated central corneal epithelium. This could be related to the deposition of subepithelial collagen fibrils seen in SND and points out a possible involvement of the corneal epithelium in the aetiology of Salzmann nodular degeneration.

Corneal dystrophies

The term corneal dystrophy embraces a heterogenous group of bilateral genetically determined non-inflammatory corneal diseases that are restricted to the cornea. The designation is imprecise but remains in vogue because of its clinical value. Clinically, the corneal dystrophies can be divided into three groups based on the sole or predominant anatomical location of the abnormalities. Some affect primarily the corneal epithelium and its basement membrane or Bowman layer and the superficial corneal stroma (anterior corneal dystrophies), the corneal stroma (stromal corneal dystrophies), or Descemet membrane and the corneal endothelium (posterior corneal dystrophies). Most corneal dystrophies have no systemic manifestations and present with variable shaped corneal opacities in a clear or cloudy cornea and they affect visual acuity to different degrees. Corneal dystrophies may have a simple autosomal dominant, autosomal recessive or X-linked recessive Mendelian mode of inheritance. Different corneal dystrophies are caused by mutations in the CHST6, KRT3, KRT12, PIP5K3, SLC4A11, TACSTD2, TGFBI, and UBIAD1 genes. Knowledge about the responsible genetic mutations responsible for these disorders has led to a better understanding of their basic defect and to molecular tests for their precise diagnosis. Genes for other corneal dystrophies have been mapped to specific chromosomal loci, but have not yet been identified. As clinical manifestations widely vary with the different entities, corneal dystrophies should be suspected when corneal transparency is lost or corneal opacities occur spontaneously, particularly in both corneas, and especially in the presence of a positive family history or in the offspring of consanguineous parents. Main differential diagnoses include various causes of monoclonal gammopathy, lecithin-cholesterol-acyltransferase deficiency, Fabry disease, cystinosis, tyrosine transaminase deficiency, systemic lysosomal storage diseases (mucopolysaccharidoses, lipidoses, mucolipidoses), and several skin diseases (X-linked ichthyosis, keratosis follicularis spinolosa decalvans). The management of the corneal dystrophies varies with the specific disease. Some are treated medically or with methods that excise or ablate the abnormal corneal tissue, such as deep lamellar endothelial keratoplasty (DLEK) and phototherapeutic keratectomy (PTK). Other less debilitating or asymptomatic dystrophies do not warrant treatment. The prognosis varies from minimal effect on the vision to corneal blindness, with marked phenotypic variability.

Avellino corneal dystrophy worsening after laser in situ keratomileusis: further clinicopathologic observations and proposed pathogenesis

PURPOSE

To study the nature of the deposits in Avellino corneal dystrophy (ACD) worsening after laser in situ keratomileusis (LASIK), and suggest a mechanism for histopathogenesis.

DESIGN

Interventional case report.

METHODS

A 28-year-old woman previously diagnosed with bilateral ACD underwent bilateral LASIK. The corneal dystrophy progressively worsened bilaterally, one year later. A penetrating keratoplasty was subsequently performed on the right eye at 31 years of age, and in the left eye a year later. The clinical and histopathologic findings of the corneal graft of the right eye were reported in the literature, with positivity to the Masson trichrome stain, negative staining with Congo red, and heterozygosity for the Arg124His mutation by serum DNA studies. Histopathologic studies of the corneal graft of the left eye were conducted at the University of Texas Southwestern Medical Center.

RESULTS

Histopathologic examination of the excised cornea showed the Masson trichrome positive deposits present from underneath the Bowman layer to the LASIK interface, with absence of deposits posterior to the latter. In contrast to the prior report describing findings in the corneal graft of the left eye, the deposits stained lightly with Congo red, but failed to show birefringence under polarized light, or fluorescence with thioflavin T.

CONCLUSION

Accelerated deposits developing after LASIK in ACD eyes seem to harbor pre-amyloid features. The epithelium is likely to be the culprit, in a pathway independent of with human transforming growth hormone beta (TGF-beta), with deposits developing in the anterior stroma and the stromal interface.

Recurrence of lattice corneal dystrophy caused by incomplete removal of stroma after deep lamellar keratoplasty

PURPOSE

To report clinical and histopathological characteristics of postoperative amyloidosis recurrence in a patient with lattice corneal dystrophy (LCD) type I.

METHODS

The clinical manifestation of recurrent amyloidosis in the residual stroma was delineated in a patient with LCD type I after deep lamellar keratoplasty (DLKP) for 6.5 years. Complete removal of the residual recipient stroma and regrafting of a new cryopreserved donor button were accomplished by a secondary DLKP. The primary DLKP donor graft and the underlying residual stroma of the recipient obtained by the secondary DLKP were examined for analysis of histopathologic and ultrastructural changes.

RESULTS

A tongue-shaped retained stroma with linear opacity was observed underneath the primary DLKP donor graft. The retained stromal layer was thoroughly detached from Descemet membrane, removed, and followed by grafting a new cryopreserved button. The primary donor button exhibited a normal epithelium, fewer keratocytes, an intact Descemet membrane, and mild positive Congo red staining in the middle layer of the stroma. The total retained recipient stroma removed by the secondary DLKP measured approximately 20 mum in thickness, showing thick and massive amyloid accumulation. The surface of the removed residual stroma toward Descemet membrane showed collagen fibers in an interwoven fashion without bundle structure under a scanning electron microscope.

CONCLUSION

Incomplete removal of the recipient stroma by DLKP can lead to the recurrence of amyloidosis in the residual stroma in patients with LCD. Clinical and histologic findings in the primary graft and in the residual recipient stroma implicate stromal genesis of recurrence of LCD after DLKP.

In vivo confocal microscopy in recurrent granular dystrophy in corneal graft after penetrating keratoplasty

Two case reports of recurrent granular dystrophy in corneal grafts after penetrating keratoplasty are presented. Slit-lamp examination and confocal microscopy (HRT II) were performed in two patients with recurrent granular dystrophy. All confocal microscopic findings of granular dystrophy were evaluated in the graft. Dystrophic lesions of the donor cornea presented the same confocal microscopic aspects in both eyes, and were similar to granular dystrophy lesions. Confocal microscopy is an imaging method that may provide new information on corneal microanatomy in dystrophies. It may be particularly useful in improving the early diagnosis of dystrophic lesions in corneal grafts.

Excimer laser exacerbation of Avellino corneal dystrophy

We review the clinical, histopathological, and ultrastructural findings and DNA phenotyping of a patient with Avellino corneal dystrophy exacerbated by laser in situ keratomileusis. The findings are reported and interpreted in the context of a literature review. The case highlights the possible difficulty of recognizing subtle dystrophic findings, as well as the importance of avoiding refractive surgical intervention in patients with Avellino corneal dystrophy to avoid exacerbation of dystrophic deposits in the cornea and subsequent reduction in vision.

Effects of corneal neovascularization on the manifestations of Avellino corneal dystrophy (granular corneal dystrophy type II)

PURPOSE

To evaluate the corneal deposits of Avellino corneal dystrophy (ACD) in patients with corneal neovascularization from pterygium or phthisis bulbi as a way of understanding the pathogenesis of ACD.

METHODS

Five patients with ACD with pterygium, 10 patients with ACD (age >50 years) without pterygium, 1 patient with ACD with phthisis bulbi with corneal neovascularization, and 1 patient with ACD with phthisis bulbi without corneal neovascularization were examined. The corneal deposits of all patients were assessed by slit-lamp examination and reviewed with biomicroscopic photographs. The distance between the limbus and the nearest corneal opacities was measured.

RESULTS

In eyes with vascularized nasal pterygia, there was a granule-free zone adjacent to the advancing edge of the pterygium so that the distance between the nasal limbus and the most nasally located granule exceeds that of the distance between the limbus and the closest granule elsewhere on the cornea. In patients with ACD with phthisis bulbi, no granular deposits were observed in the cornea with neovascularization, but there were deposits in the cornea without neovascularization.

CONCLUSION

Corneal neovascularization prevents the deposition of corneal opacities in patients with ACD.

Light and inherited retinal degeneration

Light deprivation has long been considered a potential treatment for patients with inherited retinal degenerative diseases, but no therapeutic benefit has been demonstrated to date. In the few clinical studies that have addressed this issue, the underlying mutations were unknown. Our rapidly expanding knowledge of the genes and mechanisms involved in retinal degeneration have made it possible to reconsider the potential value of light restriction in specific genetic contexts. This review summarises the clinical evidence for a modifying role of light exposure in retinal degeneration and experimental evidence from animal models, focusing on retinitis pigmentosa with regional degeneration, Oguchi disease, and Stargardt macular dystrophy. These cases illustrate distinct pathophysiological roles for light, and suggest that light restriction may benefit carefully defined subsets of patients.

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.

Avellino corneal dystrophy exacerbated after LASIK: scanning electron microscopic findings

PURPOSE

To evaluate the ultrastructure of the cornea of Avellino corneal dystrophy (ACD) exacerbated by LASIK.

METHODS

Three ACD patients with exacerbation of granular corneal deposits after LASIK underwent surgical removal of the corneal flap. The corneal flap was processed for scanning electron microscopy (SEM).

RESULTS

SEM of all patients showed abnormal granular clusters in the fibrils of the corneal flap.

CONCLUSION

Laser in situ keratomileusis induces corneal collagen abnormalities and adhesions of granular material in ACD patients.

[Microkeratome-assisted lamellar keratoplasty for recurrent corneal granular dystrophy after phototherapeutic keratectomy]

OBJECTIVE

To evaluate the safety and efficacy of microkeratome-assisted lamellar keratoplasty (MLK) for the treatment of recurrent granular corneal dystrophy (GCD) after phototherapeutic keratectomy (PTK).

METHODS

We performed a prospective study of nine eyes (seven patients) with recurrent granular dystrophy after PTK. A microkeratome was used to cut partial-thickness sections through the anterior surface of the donor and host corneas. The donor disc was placed on the recipient bed with four or eight interrupted sutures. The stitches were removed between 4 and 6 weeks after surgery. Visual acuity (VA), corneal clarity, corneal thickness, and corneal topography were assessed before and at different time points after surgery.

RESULTS

During a mean follow-up period of (18.9 +/- 4.1) months, all grafts were transparent without visible opacity at the interface, and no serious complications occurred. The VA was improved in all cases. seven eyes had best corrected visual acuity with spectacles of 20/40 or better, two eyes reached 20/25. At the last follow-up visit more than 12 months postoperatively, the mean corneal refractive power increased significantly by (2.34 +/- 0.93) D (P < 0.01), and the corneal astigmatism significantly decreased by (0.91 +/- 0.98) D (P < 0.05). The mean corneal thickness was (477.4 +/- 26.9) microm preoperatively and (507.8 +/- 23.4) microm at the last follow-up visit (P < 0.01).

CONCLUSIONS

Our findings suggest that MLK for the treatment of recurrent GCD is a safe and easy-to-perform method for restoring VA.

Automated Lamellar Keratoplasty for Recurrent Granular Corneal Dystrophy After Phototherapeutic Keratectomy

PURPOSE

To evaluate the safety and efficacy of automated lamellar keratoplasty for the treatment of recurrent granular corneal dystrophy after phototherapeutic keratectomy (PTK).

METHODS

We performed a prospective interventional noncomparative case study of nine eyes (seven patients) with severe recurrent granular corneal dystrophy after PTK. An automated microkeratome was used to cut partial-thickness sections through the anterior surface of the donor and host corneas. The donor disc was placed on the recipient bed with four or eight interrupted sutures. The sutures were removed between 4 and 6 weeks postoperatively. Visual acuity, corneal clarity, corneal thickness, and corneal topography were assessed before and at different time points after surgery.

RESULTS

During a mean follow-up period of 18.9 +/- 4.1 months, all grafts were transparent without visible opacity at the interface, and no serious complications occurred. In all cases, the visual acuity improved: seven eyes had best spectacle-corrected visual acuity of > or = 20/40; two eyes reached 20/25. At last follow-up > 12 months postoperatively, the mean corneal refractive power had significantly increased by 2.34 +/- 0.93 diopters (D) (P<.001), and the corneal astigmatism significantly decreased by 0.91 +/- 0.98 D (P<.05). The mean corneal thickness was 477.4 +/- 26.9 microm preoperatively and 507.8 +/- 23.4 microm at last follow-up (P<.001).

CONCLUSIONS

Our findings suggest that automated lamellar keratoplasty for the treatment of recurrent granular corneal dystrophy is a safe and effective method of improving visual acuity, but recurrence remains a risk.

Recurrence of chromosome 10 Thiel-Behnke corneal dystrophy (CDB2) after excimer laser phototherapeutic keratectomy or penetrating keratoplasty

PURPOSE

To evaluate the recurrence of Thiel-Behnke dystrophy (linked to the 10 q23-q24 locus) after phototherapeutic keratectomy or penetrating keratoplasty.

METHODS

This is a retrospective study of 4 patients (8 eyes) who underwent phototherapeutic keratectomy and 1 patient (2 eyes) who underwent penetrating keratoplasty. Best corrected visual acuity was assessed, and biomicroscopic examinations for evidence of recurrent dystrophy were documented and photographed. The location, lesion distribution, and lesion pattern of any recurrence was noted.

RESULTS

Follow-up ranged from 8 months to 25 years (mean +/- SD 9.7 +/- 7.97 years). All 10 eyes showed biomicroscopic evidence of central recurrence. Six eyes showed an intermediate zone of honeycomb opacities as well as a peripheral zone of focal and geographic lesions. Despite the high incidence of recurrence, functional central visual acuity was maintained. All eyes maintained functional best corrected visual acuity (ranging from 20/25 to 20/80) despite the postoperative recurrence.

CONCLUSION

Recurrence of Thiel-Behnke corneal dystrophy is extremely high after either phototherapeutic keratectomy or penetrating keratoplasty. Despite the high incidence of recurrence, the central cornea is the last to be affected. The peripheral-to-central progression of the lesions points to an epithelial origin for the pathogenesis of the dystrophy. Phototherapeutic keratectomy in the treatment of Thiel-Behnke corneal dystrophy offers a safe and effective treatment modality, providing patients up to 8 years of improved vision ranging from 8 months to 8 years (mean +/- SD 3.7 +/- 2.7 years) and delaying or circumventing the need for more invasive intraocular surgical intervention.

Complications associated with anterior basement membrane dystrophy after laser in situ keratomileusis

PURPOSE

To evaluate the complications associated with anterior basement membrane dystrophy (ABMD) after laser in situ keratomileusis (LASIK).

SETTING

Cornea Service, Wills Eye Hospital, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.

METHODS

In this noncontrolled retrospective case series, the medical records of all patients with LASIK complications seen in the Cornea Service at Wills Eye Hospital from January 1, 1998, to December 31, 2002, were reviewed. All patients who presented with ABMD changes after LASIK were included in the study. Patients with a history of trauma before or after surgery were excluded.

RESULTS

Thirty-five eyes of 18 patients were included. The mean age was 46.2 years. Thirteen eyes (37.1%) had a flap-lift procedure to remove epithelial ingrowth or for an enhancement. The most common reason for the visit was visual complaints, which were seen in 77.8% of patients. Seven patients (38.9%) had visual complaints alone; 27.8% had visual complaints associated with recurrent erosions and 11.1%, with dry eyes. Four patients (22.2%) had recurrent corneal erosions with no visual complaints. On examination, the most common finding was negative staining with fluorescein dye within the LASIK flap, which was seen in all patients. In addition to the ABMD changes, 25.7% had some degree of epithelial ingrowth and 45.7%, irregular astigmatism.

CONCLUSIONS

Anterior basement membrane dystrophy changes post LASIK were associated with visual complaints and/or recurrent erosions. Patients should be carefully screened for ABMD. Those who have ABMD signs or symptoms may not be ideal candidates for LASIK.

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.

A model of FAS1 domain 4 of the corneal protein beta(ig)-h3 gives a clearer view on corneal dystrophies

PURPOSE

A progressive alteration of the cornea resulting in loss of transparency occurs in a set of hereditary diseases known as corneal dystrophies. A number of these dystrophies have been linked to mutations in the 5q31-linked gene product beta(ig)-h3 (TGFBIP, kerato-epithelin, MP78/70, RGD-CAP) although the mechanism by which the mutations cause disease remains unknown. Here we investigate the structural basis for the different corneal dystrophies caused by mutations of the beta(ig)-h3 protein. The integrin binding properties of beta(ig)-h3, described in several recent studies, have been analysed with respect to the beta(ig)-h3 structure.

METHODS

The recently determined structure of a FAS1 domain pair from fasciclin I, an insect cell adhesion molecule and beta(ig)-h3 homologue, was used to generate a homology model of the beta(ig)-h3 FAS1 domain 4.

RESULTS

The structural analysis of FAS1 domain 4 of beta(ig)-h3 predicts that the common mutations at positions 124 and 555 do not substantially alter the beta(ig)-h3 structure. In contrast, the rare missense mutations appear incompatible with the FAS1 fold. A number of residues implicated in integrin binding by previous mutagenesis are mostly buried and appear to have important structural roles.

CONCLUSIONS

The common mutations of beta(ig)-h3 at positions 124 and 555 are likely to affect protein-protein interactions directly, whereas the rare mutations are likely to cause misfolding of the protein within the cell. Previously identified integrin binding residues are unlikely to be directly involved in receptor binding.

Genetic linkage of Francois-Neetens fleck (mouchetée) corneal dystrophy to chromosome 2q35

Francois-Neetens fleck (mouchetée) corneal dystrophy is an autosomal dominant corneal dystrophy characterized by scattered small white flecks occurring at all levels of the corneal stroma. We report linkage of the CFD locus to D2S2289 (Z(max)=4.46, theta=0), D2S325 (Z(max)=3.28, theta=0), D2S317 (Z(max)=3.1, theta=0), D2S143 (Z(max)=3.8, theta=0.03), and D2S2382 (Z(max)=5.0, theta=0) on chromosome 2q35. Multipoint analysis confirmed linkage to the region between D2S117 and D2S126 with a maximum multipoint lod score of 5.0 located midway between D2S2289 and D2S325. Analysis of CFD in these same families assuming a 90% penetrance increased the maximum lod score to 6.28 at D2S157.

Recurrence of corneal stromal dystrophies after penetrating keratoplasty

PURPOSE

To assess the rates of simple and clinically significant recurrences of stromal dystrophies in corneal grafts.

METHODS

We conducted a retrospective review of Wills Eye Hospital records from 1984 to 2001, identifying all patients with stromal corneal dystrophies who had penetrating keratoplasties. Kaplan-Meier curves and chi analysis were performed.

RESULTS

The study population consisted of 35 eyes (21 patients) with lattice dystrophy, 17 eyes (10 patients) with corneal dystrophy of Bowman's membrane (CDB), 14 eyes (eight patients) with macular dystrophy, seven eyes (five patients) with granular dystrophy, and four eyes (four patients) diagnosed with Schnyder's crystalline dystrophy. There was a simple recurrence in 21 (60%) eyes (14 patients) with lattice and in 15 (88%) eyes (eight patients) with CDB. The median time to simple recurrence for the first eye transplanted of each patient was 8.4 years for lattice and 2.0 years for CDB. After 5 years of follow-up, there was a clinically significant recurrence, manifested by recurrent erosions or associated with decreased visual acuity, in the first eye transplanted of each patient, respectively, in six (17.1%) and seven (20%) eyes with lattice and in two (11.8%) and three (17.6%) eyes with CDB.

CONCLUSION

Corneal dystrophy of Bowman's membrane has the highest rate of simple recurrence followed by granular and lattice dystrophies, respectively. However, the rate of clinically significant recurrence, both recurrent erosions and decreased visual acuity, in the first 5 years is similar in CDB and lattice dystrophies. Recurrence is infrequent in macular and Schnyder's crystalline dystrophy. As expected, in genetic diseases, the potential for recurrence exists and increases with follow-up time.

Pre-Descemet's corneal dystrophy associated with ichthyosis

Pre-Descemet's dystrophy is a symmetrical bilateral comeal dystrophy consisting of multiple small discrete opacities of lipid-like material in the deep stroma just anterior to the pre-Descemet's membrane. We presented a case of a 46-year-old male who visited our hospital on account of acute conjunctivitis. On routine examination, we found multiple fine gray dots in the pre-Descemet's area and large, dark, scaly skin lesions over extensor surfaces of the extremities. After consultation with a dermatologist, X-linked recessive ichthyosis was diagnosed.

Phototherapeutic keratectomy for anterior basement membrane dystrophy after laser in situ keratomileusis

OBJECTIVE

To evaluate the efficacy and safety of phototherapeutic keratectomy (PTK) in the treatment of symptomatic anterior basement membrane dystrophy following laser in situ keratomileusis (LASIK).

METHODS

In a retrospective study, 10 eyes of 10 patients that developed symptomatic anterior basement membrane dystrophy following LASIK for myopia were treated with PTK using the VISX S2 (VISX Inc, Santa Clara, Calif) excimer laser. Primary outcome measurements including corneal clarity, resolution of symptoms, uncorrected visual acuity (UCVA), manifest refraction, best spectacle-corrected visual acuity (BSCVA), and complications were evaluated preoperatively, 1 day postoperatively, and at the last postoperative follow-up visit.

RESULTS

At the last follow-up visit (mean [SD], 8.8 [5.5] months; range, 4-22 months), 100% of the eyes had clear corneas with no evidence of anterior basement membrane dystrophy, and all eyes were asymptomatic. Mean spherical equivalent changed from -0.75 (0.99) diopters (D) (range, -2.75 to +0.25 D) preoperatively to -0.51 (0.80) D (range, -1.63 to +1.00 D) at the last follow-up visit (P =.64). Uncorrected visual acuity improved from 20/20 or better in 1 eye (10%) and 20/40 or better in 5 eyes (50%) preoperatively to 20/20 or better in 5 eyes (50%) and 20/40 or better in 7 eyes (70%) postoperatively. No eyes lost lines of BSCVA, 2 eyes gained 1 line, 2 eyes gained 2 lines, and 1 eye gained 4 lines. There was a statistically significant improvement in mean logMAR BSCVA postoperatively, improving from 0.06 (0.16) (range, -0.1 to +0.3) to -0.08 (0.07) (range, -0.1 to +0.1) (P =.04). Postoperative complications included diffuse lamellar keratitis that resolved after treatment without sequelae (20%) and induced myopia exceeding -1.50 D (10%).

CONCLUSION

Phototherapeutic keratectomy for the treatment of symptomatic anterior basement membrane dystrophy following LASIK treatment is safe and effective.

Exacerbation of Avellino corneal dystrophy after laser in situ keratomileusis

PURPOSE

To report a case of Avellino corneal dystrophy that increased in severity 1 year after uncomplicated laser in situ keratomileusis (LASIK) for myopia.

METHODS

Avellino dystrophy was confirmed by polymerase chain reaction sequencing of DNA from the patient and her parents.

RESULTS

Best spectacle-corrected visual acuity decreased from 20/20 to 20/30 12 to 20 months after LASIK owing to opacities that appeared centrally in the corneal stroma and the LASIK flap and remaining posterior stroma interface.

CONCLUSIONS

LASIK is contraindicated in patients with Avellino corneal dystrophy because vision may be reduced by corneal opacities that appear in the interface of the flap and remaining posterior stroma postoperatively.

Different recurrence patterns after phototherapeutic keratectomy in the corneal dystrophy resulting from homozygous and heterozygous R124H BIG-H3 mutation

PURPOSE

To report the recurrence pattern of corneal deposits after phototherapeutic keratectomy in patients with corneal dystrophies resulting from homozygous and heterozygous Arg124His (R124H) mutation of the BIG-H3 gene.

METHODS

Slit-lamp examination was performed on patients with corneal dystrophy resulting from a genetically confirmed BIG-H3 R124H mutation.

RESULTS

The recurrence of corneal deposits after phototherapeutic keratectomy in patient with heterozygous R124H mutation was mild; the granular opacities occurred as spot lesions in the central cornea. The patient with a homozygous mutation had a more severe pattern, and the recurrent lesions were diffuse and occurred in the periphery between the corneal epithelium and laser-ablated stroma. The recurrence-free interval in homozygous patients was shorter.

CONCLUSION

The mutation genotype of BIG-H3 gene determines the recurrence pattern after phototherapeutic keratectomy.

Corneal morphology and sensitivity in lattice dystrophy type II (familial amyloidosis, Finnish type)

PURPOSE

To describe the corneal abnormalities and to measure different modalities of corneal sensitivity in corneal lattice dystrophy type II (familial amyloidosis, Finnish type, also known as gelsolin-related amyloidosis and originally as Meretoja syndrome).

METHODS

Twenty eyes of 20 patients were examined by in vivo confocal microscopy and noncontact gas esthesiometry.

RESULTS

Pleomorphism of, and dense deposits between or posterior to, the basal epithelial cells were frequently observed, as well as a reduction of long nerve fiber bundles in the subbasal nerve plexus. The anterior stroma was altered in most cases, with fibrosis and abnormal extracellular matrix. In 15 corneas, thick anterior and midstromal filaments, corresponding to lattice lines, and in 11 corneas, thin undulated structures were observed. The average mechanical sensitivity threshold of 12 subjects was increased, and in the remaining 8 subjects there was no response, even to the highest intensity of stimuli used. Three patients did not respond to CO(2), 11 to heat, and 2 to cold, but those patients who responded had normal thresholds. Patients with more long nerve fiber bundles per confocal microscopic image had better mechanical and cold sensitivity than patients with fewer nerve fiber bundles.

CONCLUSIONS

Lattice lines seem to be related to amyloid material and not to corneal nerves. However, the subbasal nerve density appears reduced, which results mainly in a decrease in mechanical and, to a lesser extent, thermal sensitivity. The location of stromal filaments and undulated structures changes with increasing age.

Absence of ocular manifestations in autosomal dominant Alport syndrome associated with haematological abnormalties

Most patients with Alport syndrome have X-linked or autosomal recessive disease that is characterised by renal failure, hearing loss, and, in nearly 75% of the cases, a dot-and-fleck retinopathy and anterior lenticonus. There are only case reports of individuals with the rare autosomal dominant form, who can have haematuria or renal failure, deafness, and, in addition, low platelet counts and neutrophil inclusions. The ocular features of autosomal dominant inheritance have not been described. We have examined the eyes in the members of two families where Alport syndrome was diagnosed on the basis of the clinical features and family history, and where autosomal dominant inheritance was confirmed by father-to-son disease transmission, the associated haematological abnormalities, and haplotypes that segregated with the recently described locus at chromosome 22q. In Family A, the eyes of two individuals with haematuria, hearing loss, and haematological abnormalities and of nine unaffected family members were examined. In Family B, the eyes of two individuals with renal failure, normal hearing, and haematological abnormalities were examined. None of the affected or unaffected members in either family had a dot-and-fleck retinopathy, anterior lenticonus, a history suggesting recurrent corneal erosions, or corneal dystrophy. These results indicate that the protein abnormality in autosomal dominant Alport syndrome does not produce the retinopathy and lenticonus typical of X-linked and autosomal recessive disease. This may be because the abnormal protein is not present or is less important in the ocular basement membranes than elsewhere, or because the presence of a normal allele in autosomal dominant disease compensates for the defective allele.

In vitro creation of amyloid fibrils from native and Arg124Cys mutated betaIGH3((110-131)) peptides, and its relevance for lattice corneal amyloid dystrophy type I

BetaIGH3 protein has been recently involved in the pathogenesis of blinding corneal diseases, some of which have characteristic amyloid corneal deposits. The 124 codon of the betaig-h3 gene seems to be crucial for the amyloidogenicity of the protein product. We presently report an in vitro system that reproducibly forms amyloid fibrils from betaIGH3((110-131)) derived peptides. We also assessed the differences in fibril formation of two 22-amino acid peptides centered on the 124 residue: the native form and the Arg124Cys peptide (mutation linked to lattice corneal amyloid dystrophy type 1). After dialysis of Arg124Cys peptide against PBS 1/15 M pH 7.4 for 72 hours, Congo red staining and electron microscopy demonstrated the presence of abundant material fulfilling the criteria of amyloid. Quantitative analysis with thioflavine T fluorescence studies confirmed the high capacity of Arg124Cys peptide to form amyloid fibrils when compared to the native form.

Advances in the molecular genetics of corneal dystrophies

PURPOSE

To improve our understanding of the role of specific genes on corneal transparency through a review of linkage to specific chromosomal loci and the identification of the mutant genes dealing with the corneal dystrophies.

METHOD

Relevant recent literature on the corneal dystrophies is reviewed.

RESULTS

Molecular genetic studies of the corneal dystrophies suggest that genes on at least 10 human chromosomes are involved in the maintenance of corneal transparency (chromosomes 1, 5, 9, 10, 12, 16, 17, 20, 21, and X). Within the 10 chromosomes to which corneal dystrophies have been mapped, specific genetic mutations in seven genes (GSN, BIGH3, KRT3, See also pp. 687-691. KRT12, MSS1, GLA, and ARSC1) have been identified in 15 corneal dystrophies. Some corneal dystrophies that are considered distinct clinicopathologic entities are actually caused by different mutations in the same gene. For example, lattice dystrophy types I and IIIA, granular corneal dystrophy types I, II (Avellino dystrophy), and III (Reis-Bucklers dystrophy), and Thiel-Behnke corneal dystrophy are the result of mutations in BIGH3. Mutations in three genes (GSN, BIGH3, MSS1) are associated with amyloid deposition in the cornea. A gene for keratoconus has been mapped to chromosome 21, which is noteworthy because of the established association of keratoconus in Down syndrome (trisomy 21).

CONCLUSION

Recent genetic studies on the corneal dystrophies provide insight into some of these disorders at a basic molecular level. Some corneal dystrophies that were previously believed to be distinct clinicopathologic entities are closely related at the molecular level with the different phenotypes resulting from distinct mutations in the same gene. This new knowledge is leading to a revised classification of the corneal dystrophies and to the development of animal models of corneal dystrophies. The latter will lead to a better understanding of the pathogenesis of the disorders and hence to novel therapeutic approaches to those dystrophies that cause significant visual impairment. Research of this nature is only in its infancy.

On the role of kerato-epithelin in the pathogenesis of 5q31-linked corneal dystrophies

PURPOSE

Recently, the authors identified a gene, BIGH3, in which different mutations cause a group of hereditary corneal dystrophies: lattice type I and IIIA (CDLI and CDLIIIA), granular Groenouw type I (CDGGI), Avellino (CDA), and Reis-Bücklers' (CDRB). All these disorders are characterized by the progressive accumulation of corneal deposits with different structural organization. Experiments were conducted to determine the role of kerato-epithelin (KE), the product of BIGH3, in the pathogenesis of the diseases.

METHODS

KE-15 and KE-2, two rabbit antisera raised against peptides from the 69-364 and 426 - 682 amino acid regions of KE respectively, were used for immunohistology of the corneas obtained after keratoplasty in six CDLI patients, three CDGGI patients, and one CDA patient.

RESULTS

The nonamyloid deposits observed in CDGGI stained intensively with KE-15 and KE-2, whereas the amyloid deposits in all analyzed CDLI corneas reacted to KE-2 but not to KE-15. In the CDA cornea, where amyloid and nonamyloid inclusions were present, positive staining with both antisera was observed.

CONCLUSIONS

Pathologic amyloid and nonamyloid deposits observed in CDLI, CDGGI-, and CDA-affected corneas are caused by KE accumulation. Different staining patterns of amyloid and nonamyloid deposits observed with antibodies against the amino and carboxyl termini of KE suggest that two mechanisms of KE misfolding are implicated in the pathogenesis of 5q31-linked corneal dystrophies.

Recurrence of corneal dystrophy after excimer laser phototherapeutic keratectomy

BACKGROUND

Excimer laser phototherapeutic keratectomy (PTK) can be useful to treat anterior corneal dystrophies both before and after penetrating keratoplasty.

OBJECTIVE

To evaluate the recurrence of corneal dystrophies after excimer laser PTK.

DESIGN

Retrospective case series.

PARTICIPANTS

Fifty excimer laser PTK procedures were performed in 43 eyes of 33 patients with corneal dystrophies. Preoperative diagnoses included Reis-Bücklers dystrophy (13 eyes), granular dystrophy (11 eyes), anterior basement membrane (ABM) dystrophy (11 eyes), lattice dystrophy (7 eyes), and Schnyder crystalline dystrophy (1 eye).

INTERVENTION

Two excimer lasers (VISX 20/20 model B and VISX Star) were used to perform all PTKs.

MAIN OUTCOME MEASURES

After PTK, patients were followed on a regular basis with measurement of best-corrected visual acuity and biomicroscopic examination. Evidence of recurrent dystrophy was noted according to specific criteria.

RESULTS

Follow-up range was from 1.1 to 71.2 months (mean, 19.5 months). Clinically significant recurrent dystrophy occurred in 17 eyes. The ABM dystrophy recurred in the form of recurrent corneal erosions in 5 (42%) of the 12 eyes within 6 to 9 months of PTK. Four of these five eyes had mild erosions, which were treated successfully with topical medications while one eye required an additional PTK for an erosion outside the initial treatment area. Eight (47%) of 17 eyes with Reis-Bücklers dystrophy developed clinically significant recurrence an average of 21.6 months after PTK. Three (23%) of 13 eyes with granular dystrophy were found to have a significant recurrence a mean of 40.3 months after PTK. Only one (14%) of seven eyes with lattice dystrophy developed a significant recurrence at 6 months after PTK. Six eyes with significant recurrence after PTK were retreated successfully with additional PTK. Three eyes later developed recurrence of granular and Reis-Bücklers dystrophy after the second PTK. The probability of recurrence of these dystrophies after PTK was calculated using the Kaplan-Meier survival analysis.

CONCLUSION

Phototherapeutic keratectomy can restore and preserve useful visual function for a significant period of time in patients with anterior corneal dystrophies. Even though corneal dystrophies are likely to recur eventually after PTK, successful retreatment with PTK is possible.

Recurrent macular corneal dystrophy type II 49 years after penetrating keratoplasty

Recurrence of macular corneal dystrophy after keratoplasty is rare. We report light microscopic, immunohistochemical, electron microscopic, and serologic findings in a 78-year-old woman who underwent regrafting 49 years following the first penetrating keratoplasty. Examination of the corneal button revealed deposits of glycosaminoglycans in the graft beneath the Bowman layer, throughout the stroma, and in the endothelium with positive staining for antigenic keratan sulfate. By transmission electron microscopy, intracellular and extracellular deposits of a fibrillogranular material were detected in the stroma, Descemet membrane, and endothelium. The serum level of antigenic keratan sulfate was normal. Our findings indicate that macular corneal dystrophy type II may show late recurrence after penetrating keratoplasty with intense deposition of antigenic keratan sulfate in all corneal layers.