Laser in situ keratomileusis in patients with corneal guttata and family history of Fuchs' endothelial dystrophy

Laser refractive surgery in corneal dystrophies

Twenty-eight case reports and case series published between 2000 and 2019 concerning laser refractive surgery in patients with corneal dystrophies, resulting in 173 eyes from 94 patients, were included in this systematic review. Best results were achieved in posterior corneal polymorphous and Cogan dystrophy. Unfavorable results were found in Avellino dystrophy and Fuchs endothelial corneal dystrophy (FECD). Photorefractive keratectomy was not indicated in Meesmann and Avellino dystrophy. Laser in situ keratomileusis was indicated in posterior polymorphous corneal dystrophy but not in FECD, Avellino, or Cogan dystrophy. Small-incision lenticule extraction and other dystrophies such as lattice, fleck, Lisch, or François did not achieve enough scientific evidence to report any recommendation.

Small Incision Lenticule Extraction (SMILE) in Patients with Corneal Guttae

Purpose

To report 12-month results of small incision lenticule extraction (SMILE) in the treatment of myopia with corneal guttae (CG).

Methods

We conducted a retrospective analysis of 12 eyes from six patients who had preoperative CG without clinical sign of Fuchs’ endothelial corneal dystrophy (FECD) and had SMILE for correction of myopia. Preoperative and 12-month postoperative measurements included uncorrected distance visual acuity (UDVA), spherical equivalent (SE), endothelial cell density (ECD), the coefficient of variation (CV), the percentage of hexagonal cells (HEX), and central corneal thickness (CCT). The changes in ECD, CV, HEX, and CCT after SMILE were subjected to statistical analysis.

Results

Twelve months postoperatively, the mean SE was −0.10 ± 0.32 D and all eyes had a UDVA of 0 logMAR or better. No eyes developed corneal edema or other complication during the follow-up period. There were no significant changes in the ECD, CV, or HEX at 12 months (all p>0.05).

Conclusion

SMILE yielded improvement in visual acuity and no adverse effects to corneal endothelial cells were found when correcting myopia or myopic astigmatism in patients with CG. However, studies with a greater number of patients and longer follow-up periods are needed to establish the long-term outcomes and safety.

Reversal of laser in situ keratomileusis interface fluid after Descemet stripping automated endothelial keratoplasty for pseudophakic bullous keratopathy

To report a case of interface fluid syndrome (IFS) after laser-assisted in situ keratomileusis (LASIK) in a patient with Anterior chamber intraocular lens (ACIOL) induced corneal decompensation treated with Descemet's stripping automated endothelial keratoplasty (DSAEK). At 6 months follow-up, the cornea became clear with improvement in visual acuity and resolution of interface fluid.

Scanning Acoustic Microscopy Comparison of Descemet's Membrane Normal Tissue and Tissue With Fuchs' Endothelial Dystrophy

Purpose

To describe the application of scanning acoustic microscopy in the GHz-range (GHz-SAM) for qualitative imaging and quantitative characterization of the micromechanical properties of the Descemet's membrane and endothelial cells of cornea tissue.

Methods

Investigated were samples of a normal tissue and a tissue with Fuchs' endothelial dystrophy (FECD, cornea Guttata). Descemet's membranes were fixed on glass substrates and imaged utilizing a focused acoustic lens operating at a center frequency of 1 GHz.

Results

GHz-SAM data, based on the well-established V(z) technique, revealed discrepancies in the velocity of the propagation of Rayleigh surface acoustic waves (RSAW). RSAW were found to be slower in glass substrates with FECD samples than in the same glass substrates (soda-lime) with normal Descemet membrane, which indicates lower shear and bulk moduli of elasticity in tissues affected by FECD.

Conclusions

Noninvasive/nondestructive GHz-SAM, is utilized in this study for the imaging and characterization of Descemet membranes, fixated on glass substrates. V(z) signatures containing sufficient oscillations were obtained for the system of Descemet membranes on glass substrates. The observed variation in the microelastic properties indicates potential for further investigations with GHz-SAM based on the V(z) technique.

Descemet membrane endothelial keratoplasty and refractive surgery

PURPOSE OF REVIEW

Descemet membrane endothelial keratoplasty (DMEK) has become a first-line treatment in corneal endothelial diseases because of its exceptional clinical outcomes and low complication rates. Because of its improved refractive predictability, DMEK is now also considered for managing cases with endothelial decompensation following previous refractive procedures, or in combination with those. This article reviews the clinical outcomes in these cases and discusses the possibility of refractive interventions following DMEK.

RECENT FINDINGS

DMEK has been successfully performed in eyes after laser in-situ keratomileusis, eyes after anterior chamber intraocular lens (IOL) implantation and aphakic eyes. Often, DMEK is combined with cataract surgery (triple-DMEK). Initial reports on reducing the refractive cylinder by toric IOL implantation are available. Although there are some reports on phacoemulsification and IOL implantation after phakic DMEK, reports on laser refractive procedures following DMEK are lacking.

SUMMARY

In contrast to earlier keratoplasty techniques, DMEK induces on average only mild refractive shifts owing to the 'natural' restoration of the cornea. As such, DMEK may be ideal in managing corneal decompensation in refractive patients. However, further studies are required to assess the safety and efficacy of DMEK after refractive treatment and of refractive procedures following DMEK.

Management of Interface Fluid Syndrome After LASIK by Descemet Membrane Endothelial Keratoplasty in a Patient With Fuchs' Corneal Endothelial Dystrophy

PURPOSE

To report a case of interface fluid syndrome after LASIK in a patient with Fuchs' corneal endothelial dystrophy treated with Descemet membrane endothelial keratoplasty (DMEK).

METHODS

Case report.

RESULTS

A 74-year-old patient presented with interface fluid syndrome and was treated with DMEK. Its complications in the form of partial graft detachment and cystoid macular edema were successfully managed by rebubbling and topical treatment, respectively. The treatment led to amelioration of both visual acuity and patient satisfaction. At the examination 6 months after DMEK, the cornea was clear and corrected distance visual acuity improved to a satisfactory level.

CONCLUSIONS

Interface fluid syndrome can develop many years after LASIK as a result of corneal endothelial decompensation and can be effectively treated with DMEK. Close postoperative monitoring of patients is paramount to intervene therapeutically in case of transplant detachment or development of cystoid macular edema requiring further surgical or conservative management. [J Refract Surg. 2017;33(5):347-350.].

LASIK and surface ablation in corneal dystrophies

Corneal dystrophies are a rare group of hereditary disorders, that are bilateral, non-inflammatory, and progressive. Clinically, they can be classified based on the anatomic layer of the cornea affected. Refractive surgery and phototherapeutic keratectomy (PTK) can be performed with caution in patients with certain corneal dystrophies, but should be avoided in others. For epithelial basement membrane dystrophy, photorefractive keratectomy (PRK) is the procedure of choice for treatment of refractive error, and PTK may be performed for the treatment of recurrent erosions or irregular astigmatism. PRK and laser-assisted in situ keratomileusis (LASIK) have been associated with exacerbation of combined granular-lattice corneal dystrophy. LASIK and PRK appear to be safe in mild forms of posterior polymorphous corneal dystrophy, whereas LASIK should be avoided in Fuchs dystrophy. The safety of refractive surgery and PTK in the remainder of epithelial, Bowman layer, and stromal dystrophies has yet to be established.

The 7-year cumulative incidence of cornea guttata and morphological changes in the corneal endothelium in the Reykjavik Eye Study

PURPOSE

To examine the corneal endothelium and establish the 7-year cumulative incidence of cornea guttata (CG).

METHODS

Population-based prospective cohort study with 573 participants (third wave of the Reykjavik Eye Study (RES) in 2008). Four hundred and thirty-seven subjects had either right or left eyes available for analysis after excluding confounding eye conditions. The baseline for eyes at risk for developing CG is the second wave of the RES in 2001. Participants underwent specular microscopy and a standardized eye examination.

RESULTS

The cumulative 7-year incidence of CG in either eye was estimated as a 95% confidence interval for the expected value for both genders combined (15-23%), for males (8-18%) and for females (19-29%). In right eye only, the 7-year cumulative incidence for both genders combined was estimated to be 6-11%. For genders combined and for males only, the data indicated no correlation between 7-year cumulated incidence and age at baseline. In women, however, the change of 7-year incidence for CG in at least one eye appeared to be correlated to age at baseline. Reduction of endothelial cell density for corneas with CG at baseline was found [CI (0.95)-132 ± 94].

CONCLUSION

The cumulative 7-year incidence of primary central CG for a middle-aged and older Caucasian population without history of potentially confounding eye disease has been established. Women tend to have higher incidence if onset occurs at middle age. If CG is present, the cell density and the cell size variation decrease within a 7-year period.

Corneal endothelial cell density after myopic intra-LASIK and the effect of AC gas bubbles on the corneal endothelium

PURPOSE

To evaluate the endothelial cell density (ECD) change after laser-assisted in situ keratomileusis (LASIK) using IntraLase FS30® and the influence of anterior chamber gas bubbles (AC gas bubbles) produced during flap creation on the corneal endothelium during the excimer laser ablation.

METHODS

Myopic LASIK was performed in 436 eyes of 252 patients at Shinagawa LASIK Center. Average age was 32.4±7.05 years. IntraLase FS30® was used for flap creation and Allgretto Wave Eye-Q® 400Hz was used for excimer laser ablation. Preoperative and 3-month postoperative ECD were measured with a noncontact specular microscope (Noncon Robo FA-3509®) and compared. The preoperative and 3-month postoperative ECD changes that developed AC gas bubbles during the flap creation (19 eyes of 18 patients) were also examined. The change of ECD was compared to the group that did not produce AC gas bubbles.

RESULTS

The average ECD reduction after LASIK was -15±102 cells/mm2 for AC gas bubbles (-) group (0.51%, p>0.05) and -35±130 cells/mm2 (1.21%, p>0.05) for AC gas bubbles (+) group. There was no significant ECD change in the AC gas bubbles (-) and AC gas bubbles (+) groups, and no significant difference was observed between AC gas bubbles (-) and AC gas bubbles (+) groups.

CONCLUSIONS

IntraLase FS30® is a safe and effective tool for LASIK operation which does not cause damage to corneal endothelium. Anterior chamber gas bubbles produced during flap creation did not damage corneal endothelial cells and did not interfere with LASIK operations.

E2-2 protein and Fuchs's corneal dystrophy

BACKGROUND

Fuchs's corneal dystrophy (FCD) is a leading cause of corneal transplantation and affects 5% of persons in the United States who are over the age of 40 years. Clinically visible deposits called guttae develop under the corneal endothelium in patients with FCD. A loss of endothelial cells and deposition of an abnormal extracellular matrix are observed microscopically. In advanced disease, the cornea swells and becomes cloudy because the remaining endothelial cells are not sufficient to keep the cornea dehydrated and clear. Although rare genetic variation that contributes to both early-onset and typical late-onset forms of FCD has been identified, to our knowledge, no common variants have been reported.

METHODS

We performed a genomewide association study and replicated the most significant observations in a second, independent group of subjects.

RESULTS

Alleles in the transcription factor 4 gene (TCF4), encoding a member of the E-protein family (E2-2), were associated with typical FCD (P=2.3x10(-26)). The association increased the odds of having FCD by a factor of 30 for persons with two copies of the disease variants (homozygotes) and discriminated between case subjects and control subjects with about 76% accuracy. At least two regions of the TCF4 locus were associated independently with FCD. Alleles in the gene encoding protein tyrosine phosphatase receptor type G (PTPRG) were associated with FCD (P=4.0x10(-7)), but the association did not reach genomewide significance.

CONCLUSIONS

Genetic variation in TCF4 contributes to the development of FCD. (Funded by the National Eye Institute and others.)

Fuchs' corneal dystrophy

Fuchs' corneal dystrophy (FCD) is a progressive, hereditary disease of the cornea first described a century ago by the Austrian ophthalmologist Ernst Fuchs. Patients often present in the fifth to sixth decade of life with blurry morning vision that increases in duration as the disease progresses. Primarily a condition of the posterior cornea, characteristic features include the formation of focal excrescences of Descemet membrane termed 'guttae', loss of endothelial cell density and end-stage disease manifested by corneal edema and the formation of epithelial bullae. Recent advances in our understanding of the genetic and pathophysiological mechanisms of the disease, as well as the application of new imaging modalities and less invasive surgical procedures, present new opportunities for improved outcomes among patients with FCD.

Age-related differences in the normal human cornea: a laser scanning in vivo confocal microscopy study

AIMS

To quantify and establish baseline normative data for age-related differences in cellular and innervation density in the normal, healthy, human cornea using laser scanning in vivo confocal microscopy.

METHODS

Cross-sectional study of 85 normal subjects assessed via corneal topography and laser scanning in vivo confocal microscopy.

RESULTS

Mean age was 38+/-16 years (range 18-87 years) and 60% of subjects were female. Anterior keratocyte density declined by 0.9% per year (r = -0.423, p<0.001), posterior keratocyte density declined by 0.3% per year (r = -0.250, p = 0.021) and endothelial cell density declined by 0.5% per year (r = -0.615, p<0.001). Sub-basal nerve fibre density declined by 0.9% per year (r = -0.423, p<0.001). No association was observed between age and basal epithelial cell density, or between age and central corneal thickness, corneal astigmatism or horizontal corneal diameter (p>0.05). No association was observed between subject gender and corneal cell or innervation density.

CONCLUSIONS

Using laser scanning in vivo confocal microscopy this study highlights a significant, and relatively linear, reduction in keratocyte and endothelial cell density with increasing subject age. Interestingly, corneal sub-basal nerve fibre density also significantly decreases with increasing age. In vivo laser scanning confocal microscopy provides a safe, non-invasive method for the establishment of normative data and assessment of alterations in human corneal microstructure following surgery or disease processes.