Automated Lamellar Keratoplasty for Recurrent Granular Corneal Dystrophy After Phototherapeutic Keratectomy

Management of Stromal Corneal Dystrophies; Review of the Literature with a Focus on Phototherapeutic Keratectomy and Keratoplasty

Corneal dystrophies are a group of non-inflammatory inherited disorders of the cornea. This review considers treatment options for epithelial-stromal and stromal corneal dystrophies: namely Reis–Bücklers, Thiel–Behnke, lattice, Avellino, granular, macular and Schnyder corneal dystrophies. Where there is visual reduction, treatment options may include either phototherapeutic keratectomy (PTK) or corneal transplantation. Due to the anterior location of the deposits in Reis-Bücklers and Thiel–Behnke dystrophies, PTK is considered the treatment of choice. For lattice, Avellino, granular and macular corneal dystrophies, PTK provides temporary visual improvement; however, with recurrences, repeat PTK or a corneal transplant would be needed. For Schnyder dystrophy, should treatment be required, PTK may be the preferred option due to the potential for recurrence of the disease in corneal transplantation. This review discusses the literature and evidence base for the treatment of corneal dystrophies in terms of visual outcomes and recurrence rate.

[Granular corneal dystrophy treated with deep anterior lamellar keratoplasty: comparing histological analysis and optical coherence tomography]

Granular corneal dystrophy is a rare autosomal dominant disease. It is characterized by breadcrumb-like granular opacities in the central corneal stroma. The mutation has been localized in the TGFβI gene, which codes for keratoepithelin, an adhesion protein found in corneal epithelium and stroma. We report the case of granular corneal dystrophy in a 60-year-old man complaining of reduced visual acuity. Slit-lamp examination revealed multiple opacities in the central stroma of his left eye, and recurrent deposits in his other eye 13 years after penetrating keratoplasty. An anterior segment optical coherence tomography (Visante(®) OCT) was used to determine the location of deposits, then a deep anterior lamellar keratoplasty was performed in his left eye. The depth of the deposits revealed by Visante(®) OCT correlated well with the postsurgical histological findings. Visante(®) OCT can therefore help choose between phototherapeutic keratectomy and lamellar keratoplasty, techniques that are less invasive than penetrating keratoplasty, which is advantageous since this dystrophy is known to recur after surgery.

[Microkeratome-assisted anterior lamellar keratoplasty for the removal of corneal scar, caused by pterygium]

AIM

to present our experience with microkeratome-assisted anterior lamellar keratoplasty using a manual microkeratome.

MATERIALS AND METHODS

left eye of a 67 year old man was operated with microkeratome-assisted lamellar keratoplasty to remove a central corneal scar of the anterior stroma and to reduce secondary high-degree irregular astigmia caused by pterygium remnant. Videokeratography was performed to record the status of the cornea.

RESULTS

postoperative best-corrected visual acuity was superior to preoperative value which was 0.6 with +7.0 spherical and -2.0 cylindrical Diopters before the operation. Uncorrected visual acuity improved from 0.15 to 0.6. The topographical cylinder decreased from 7.98 D to 3.79 D, surface asymmetry index from 2.42 to 1.48, surface regularity index form 3.24 to 1.72. Minimum keratometry reading increased from 38.35 to 41.69.

CONCLUSION

microkeratome-assisted anterior lamellar keratoplasty seems to be safe and effective to remove corneal scars and reduce high degree irregular astigmia, moreover, to improve visual acuity.

Deep anterior lamellar keratoplasty with melles technique for granular corneal dystrophy

PURPOSE

The purpose of this study was to evaluate the clinical results of deep anterior lamellar keratoplasty (DALK) using the Melles technique in granular corneal dystrophy.

METHODS

Seven eyes from 5 patients who underwent DALK using Melles technique for granular corneal dystrophy were included in this study. The parameters evaluated included patients' demographics, preoperative and postoperative best spectacle-corrected visual acuities (BSCVAs), and timing and pattern of recurrence.

RESULTS

The mean age of the patients was 37 +/- 9.4 years (range 29-46 years) at the time of surgery. The mean length of follow-up (DALK to last visit) was 38.4 +/- 18.6 months (range 10-63 months). The procedure was performed without any major complication in all eyes. Mean preoperative BSCVA was 20/220 (range 20/400 to 20/100), which improved to 20/27 (range 20/30 to 20/25) at 6 months after DALK. Mean BSCVA was 20/50 (range 20/400-20/20) at last follow-up. Simple recurrence occurred in 5 (71%) of 7 eyes. The mean time from surgery to recurrence was 15.6 +/- 1.8 months (range 13-16 months). Clinically significant recurrences occurred 34 +/- 2 months after the procedures in 3 (43%) of 7 eyes. Two (30%) of 7 eyes had no recurrence at all.

CONCLUSIONS

Although granular corneal dystrophy is likely to recur after DALK, this technique can restore and preserve useful visual function for a significant period in these patients.

Excimer laser-assisted anterior lamellar keratoplasty for keratoconus, corneal problems after laser in situ keratomileusis, and corneal stromal opacities

PURPOSE

To evaluate excimer laser-assisted anterior lamellar keratoplasty to augment thin corneas as in keratoconus (<350 microm) and corneal ectasia after laser in situ keratomileusis (LASIK) and to treat anterior stromal opacities.

SETTING

Ophthalmology Department, School of Medicine, Gazi University, Ankara, Turkey.

METHODS

Thirteen eyes (5 keratoconus, 3 macular dystrophies, 1 post-LASIK ectasia, 1 post-LASIK interstitial keratitis, 3 post-herpetic keratitis sequelae) of 13 patients were included in this prospective study. The treatment group was divided into corneal ectasia and stromal opacity groups. A donor stromal button approximately 350 microm thick received a 100 microm excimer laser ablation on the endothelium. The remaining cornea (epithelium, Bowman's membrane, and stroma) was punched with a 7.5 or 7.7 mm trephine. After transepithelial ablation of the host cornea to 200 mum thickness, the corneal button was sutured with interrupted 10-0 monofilament nylon. Sutures were removed between 3 months and 6 months postoperatively. Preoperative and postoperative simulated keratometric cylinders and corneal thickness values were compared using the Wilcoxon signed rank test. The postoperative spherical equivalent refraction and best spectacle-corrected visual acuity (BSCVA) between the groups were compared using the Mann-Whitney U test.

RESULTS

The mean follow-up was 27.6 months +/- 8.3 (SD). All patients gained 2 lines or more of BSCVA, and no patient lost a line. The mean corneal thickness was 381.2 +/- 88.2 microm preoperatively, which significantly increased to 534.9 +/- 96.6 microm postoperatively (P < .05). The mean preoperative simulated keratometric cylinder was 7.44 +/- 7.18 diopters (D); postoperatively, it decreased to 2.61 +/- 1.73 D (P < .05). There was no significant difference in postoperative spherical equivalent refraction or BSCVA between the groups (P > .05).

CONCLUSIONS

This technique presents a different modality for the treatment of keratoconus, post-LASIK corneal problems, and other corneal stromal opacities with anterior lamellar keratoplasty. Additional studies with more patients and longer follow-up will help determine the role of this technique as a substitute for penetrating keratoplasty in these patients.