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

Mini-Review: Clinical Features and Management of Granular Corneal Dystrophy Type 2

Granular corneal dystrophy type 2 (GCD2) is an autosomal dominant corneal stromal dystrophy that is caused by p.Arg124His mutation of transforming growth factor β induced (TGFBI) gene. It is characterized by well demarcated granular shaped opacities in central anterior stroma and as the disease progresses, extrusion of the deposits results in ocular pain due to corneal epithelial erosion. Also, diffuse corneal haze which appears late, causes decrease in visual acuity. The prevalence of GCD2 is high in East Asia including Korea. Homozygous patients show a severe phenotype from an early age, and the heterozygote phenotype varies among patients, depending on several types of compound heterozygous TGFBI mutations. In the initial stage, conservative treatments such as artificial tears, antibiotic eye drops, and bandage contact lenses are used to treat corneal erosion. Different surgical methods are used depending on the depth and extent of the stromal deposits. Phototherapeutic keratectomy removes anterior opacities and is advantageous in terms of its applicability and repeatability. For deeper lesions, deep anterior lamellar keratoplasty can be used as the endothelial layer is not always affected. Recurrence following these treatments are reported within a wide range of rates in different studies due to varying definition of recurrence and follow-up period. In patients who have undergone corneal laser vision-correction surgeries such as photorefractive keratectomy, LASEK, or LASIK including SMILE surgery, corneal opacity exacerbates rapidly with severe deterioration of visual acuity. Further investigations on new treatments of GCD2 are necessary.

Contrast Sensitivity Changes after Phototherapeutic Keratectomy in Heterozygote Granular Corneal Dystrophy Type 2

Purpose: Contrast sensitivity, the ability to distinguish the relative difference in luminance of an object from its surrounding or adjacent objects, is a useful measure of visual function. In granular corneal dystrophy type 2 (GCD2), opacity of the corneal stroma causes deterioration in visual function. We compared the contrast sensitivity of GCD2 patients before and after phototherapeutic keratectomy (PTK) to evaluate the perioperative visual function in these patients.Methods: This study included 22 eyes of heterozygote GCD2 patients. The visual acuity and contrast sensitivity were measured before and after PTK. The contrast sensitivity was measured in mesopic and photopic background luminances, with glare (G) levels of 0-2 (G0, G1, and G2, respectively) and spatial frequencies at 1.5, 3, 6, 12, and 18 cycles per degree (cpd).Results: The contrast sensitivity increased after PTK at 1.5 and 3 cpd in mesopic and photopic conditions with G0-2 glare (p < 0.05). At 6 cpd, the contrast sensitivity increased in the mesopic condition with G1 glare, and in the photopic condition with G0-2 glare (p < 0.05). However, there was no change in contrast sensitivity at any glare level at 12 and 18 cpd after PTK.Conclusions: In GCD2 patients, the contrast sensitivity increased significantly after PTK. The vision of GCD2 patients, which is decreased due to corneal opacity, is improved after PTK.

De Novo L509P Mutation of the TGFBI Gene Associated with Slit-Lamp Findings of Lattice Corneal Dystrophy Type IIIA

Background: Mutations of the transforming growth factor-β-induced (TGFBI) gene produce various types of corneal dystrophy. Here, we report a novel de novo L509P mutation not located in a known hot spot of the transforming growth factor-β-induced (TGFBI) gene and its clinical phenotype, which resembles that of lattice corneal dystrophy type IIIA (LCD IIIA). Case presentation: A 36-year-old man (proband) visited our clinic due to decreased visual acuity with intermittent ocular irritation in conjunction with painful recurrent erosions in both eyes for 10 years. Molecular genetic analyses revealed a TGFBI L509P mutation (c.1526T>C) in the proband and one of his sons. Interestingly, neither TGFBI mutations nor corneal abnormalities were detected in either of the proband’s biological parents, indicating the occurrence of a de novo L509P mutation. Clinical examinations, including slit-lamp retro-illumination and Fourier-domain anterior segment optical coherence tomography (FD-OCT), revealed gray deposits in the anterior stroma and deeper refractile lines extending from limbus to limbus in both corneas of the proband, consistent with a diagnosis of LCD IIIA. Superficial diffuse haze and surface irregularity were observed in conjunction with corneal erosions and visual impairment, necessitating phototherapeutic keratectomy (PTK). A 60 μm PTK of the Bowman layer and anterior stroma of the proband’s left eye was performed following the removal of the epithelium in order to remove superficial corneal opacities. His BCVA improved from 20/400 to 20/50 at postoperative week 8 and was maintained for 45 months. Pinhole-corrected VA was 20/20 at the last visit, and corneal opacities had not recurred. Conclusions: An inheritable de novo mutation of L509P in the TGFBI gene can produce severe LCD IIIA, which can be successfully treated with OCT-guided PRK.

Long-Term Observation of Deep Anterior Lamellar Keratoplasty in Patients with Post-LASIK Granular Corneal Dystrophy Type 2: Two Case Reports

INTRODUCTION

Laser-assisted in situ keratomileusis (LASIK) exacerbates granular corneal dystrophy type 2. Post-LASIK granular corneal dystrophy type 2 is treated by several surgical techniques. To the best of our knowledge, no report has addressed the results of deep anterior lamellar keratoplasty in affected patients. Here, we report our experience regarding deep anterior lamellar keratoplasty treatment of patients with post-LASIK granular corneal dystrophy type 2.

METHODS

We describe two Japanese women who underwent deep anterior lamellar keratoplasty to treat corneal opacities that worsened after LASIK.

RESULTS

One patient had a family history of corneal dystrophies. During the initial visit to our clinic, numerous fine opacities were found at the LASIK flap interface in both patients. The clinical findings were compatible with post-LASIK granular corneal dystrophy type 2. Both patients underwent deep anterior lamellar keratoplasty by one of the authors (T.C.). In both procedures, the surgeon used a visco-dissection technique and successfully removed the whole corneal stroma. Histopathological examination of the excised corneal button from each eye revealed amyloid and hyaline deposits at the LASIK flap interface. Neither patient experienced recurrent corneal opacity during the follow-up visit at 8 years (patient 1) and 6 years (patient 2).

CONCLUSION

Deep anterior lamellar keratoplasty can be used for the treatment of post-LASIK granular corneal dystrophy type 2. Removal of the entire host stroma may be important for the prevention of recurrent corneal opacity.

Deterioration of Avellino corneal dystrophy in a Chinese family after LASIK

AIM

To reveal the importance of TGFBI gene screening for candidates with a family history of corneal disease or granular opacities in corneal stroma before refractive surgery.

METHODS

A 37-year-old male (proband) underwent bilateral laser-assisted in situ keratomileusis (LASIK) in 2002, with right vision decreased significantly in 2006. The proband and other 32 members of the family underwent a detailed ophthalmic examination, including vision acuity, intraocular pressure, slit-lamp photograph, fundus examination, optical coherence tomography (OCT) of cornea, and in vivo confocal microscope (IVCM) and peripheral blood was used for genomic DNA extraction. Seventeen TGFBI gene exons were analyzed via polymerase chain reaction amplification and direct sequencing.

RESULTS

Slit-lamp, IVCM, and OCT images showed that a large amount of dense and confluent granular opaque were seen at the interfaces of the flap and remnant stromal bed in right and light degree in left eye. Sanger sequencing showed that there was a 371G>A mutation (CGC>CAC) in exon 4, which indicated that he harbored a heterozygote R124H mutation, identifying the diagnosis of Avellino corneal dystrophy (ACD). Among the other 32 family members, 6 of them harbored the identical mutation to that in the proband.

CONCLUSION

ACD will worsen and recur after LASIK. Preoperative gene-screening for TGFBI mutations is important in diagnosing ACD.

The 25th Anniversary of Laser Vision Correction in the United States

Laser Vision Correction (LVC) is an elective, self-pay and safe surgical procedure to correct myopia and hyperopia. Since FDA approval 25 years ago, there have been a progression of technological improvements leading to better outcomes and LVC is now one of the safest surgical procedures. With a potential pool of 50 million patients, 6000 trained ophthalmic surgeons regularly treating in over 1000 centers of which 65% are physician owned. Treatments remain low from an earlier peak of 1.4 million to less than 800,000 over last 10 years. The factors preventing patients undergoing surgery have not changed and include the cost of $2000 ± $1000 per eye and fear of laser surgery on their eyes. The latter is overcome by word of mouth referrals and positive social media messaging. In addition, press misinformation and lack of optometrists participating in co-management have not helped grow LVC procedures despite the positive results of the FDA’s Patient Reported Outcomes with LASIK studies known as PROWL. The surgery is quick, and patients can be “in and out” in less than two hours with a rapid recovery, minimal postoperative restrictions and within 24 hours have 20/20 vision. Volume and price drives center and physician profitability with a scheduling capacity of two to four patients’ treatments per hour. Laser vision correction and especially LASIK, remains the treatment of choice for myopic and hyperopic patients wanting to remove their dependency on glasses and contact lenses.

Exacerbation of Granular Corneal Dystrophy Type 2 After Small Incision Lenticule Extraction

PURPOSE

To report the outcome of unilateral small incision lenticule extraction (SMILE) in a patient with granular corneal dystrophy type 2 (GCD2).

METHODS

Slit-lamp photography and Fourier domain optical coherence tomography were used to document the clinical course and appearance of the corneas in a patient with genetically determined GCD2 who underwent unilateral SMILE in the right eye.

RESULTS

Slit-lamp examination of a 23-year-old woman revealed 2 faint opacities at the surgical interface approximately 2 months after the SMILE procedure had been performed on her right eye. Nine and 3 typical GCD2 deposits located immediately beneath the Bowman layer were observed in the right and left corneas, respectively. Over time, the deposits at the interface increased in size, density, and number in the right eye. Fourier domain optical coherence tomography performed 33 months after the SMILE procedure revealed deposits at the SMILE interface that were distinct from those located immediately beneath the Bowman layer. The severity of disease exacerbation was less in this patient than what is typically observed in others who have undergone laser-assisted in situ keratomileusis or photorefractive keratectomy.

CONCLUSIONS

SMILE is contraindicated in patients with GCD2, as are other corneal refractive surgical procedures. This case highlights the importance of genetic testing before the performance of refractive corneal procedures-especially for patients with corneal opacities on preoperative slit-lamp examination or a family history of corneal disease compatible with that of a corneal dystrophy.

Fourier-domain optical coherence tomography-guided phototherapeutic keratectomy for the treatment of anterior corneal scarring

AIM

To evaluate the safety, visual and anatomic outcomes of fourier-domain optical coherence tomography (FD-OCT)-guided excimer laser phototherapeutic keratectomy (PTK) combined with photorefractive keratectomy (PRK) surgery in treating anterior corneal scarring.

METHODS

Clinical data of 23 eyes of 21 patients with anterior corneal scarring underwent FD-OCT-guided PTK and PRK from Dec. 2014 to Jul. 2016 were reviewed. Patients were assessed for preoperative and postoperative uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), contrast sensitivity (CS), FD-OCT, corneal topography and colour figures of anterior segments.

RESULTS

The preoperative corneal pathologic conditions included viral keratitis (7 patients, 7 eyes), band keratopathy (2 patients, 4 eyes), corneal dystrophy (4 patients, 4 eyes), traumatic corneal disease (2 patients, 2 eyes) and corneal chemical injury (6 patients, 6 eyes). Mean follow-up time was 10.65 (range, 3-19)mo. UCVA (in logMAR) improved from a mean of 0.79 (95%CI, 0.28-1.29) preoperatively to a mean of 0.45 (95%CI, 0.29-0.62) postoperatively (P=0.021). BSCVA (in logMAR) improved from 0.57 (95%CI, 0.27-0.88) preoperatively to a mean of 0.28 (95%CI, 0.15-0.41) postoperatively (P=0.001). Corneal topographic indices postoperatively showed significant improvement in corneal cylinder (P=0.009), the surface regularity index (P=0.007) and surface asymmetry index (P=0.00). Postoperative spherical equivalent averaged -0.53 diopters (-1.49 to 0.42). No complications were associated with the treatment.

CONCLUSION

FD-OCT-guided PTK combined with PRK is safe and effective for the treatment of anterior corneal scarring by eliminating or reducing corneal opacities.

Granular corneal dystrophy recurrence at the posterior graft-host interface after type 1 big bubble deep anterior lamellar keratoplasty

Purpose

To describe our observations of granular corneal dystrophy (GCD) recurrence isolated to the posterior graft-host interface after type 1 big bubble (BB) deep anterior lamellar keratoplasty (DALK).

Observations

We performed a retrospective chart review of 3 eyes in 2 patients, and literature review to summarize GCD recurrence patterns after DALK. A 29-year-old man with GCD underwent DALK by type 1 BB technique. Three years following surgery, he was found to have recurrence of GCD deposits isolated to the posterior graft-host interface. Similarly, a 53-year-old woman with GCD underwent DALK by BB type 1 technique, and was noted to have trace residual deposits at the posterior graft-host interface that increased in number and size over the course of 6 years. Her fellow eye underwent DALK with type 2 BB formation, without evidence of graft-host interface recurrence over a four year period. Our literature review describes the recurrence patterns of 18 cases of GCD following DALK.

Conclusions and importance

DALK can be prone to GCD recurrence in the central posterior graft-host interface. Recurrent deposits isolated to the posterior graft-host interface following type 1 BB DALK supports the hypothesis that GCD recurrence may be due to residual pathologic keratocytes in the pre-Descemet layer (PDL).