Automated superficial lamellar keratectomy augmented by excimer laser masked PTK in the management of severe superficial corneal opacities

Anterior segment optical coherence tomography for superficial keratectomy

PURPOSE

To report the use of anterior segment optical coherence tomography (AS-OCT) for superficial keratectomy (SK) in anterior corneal opacity.

METHODS

The characteristics of 43 eyes (39 patients) with various lesions responsible for anterior corneal opacity were included in this retrospective non-comparative study. AS-OCT was performed on all eyes before surgery. The thickness of corneal opacity and the underlying healthy stroma were measured. SK was performed on each individual.

RESULTS

Four types of anterior corneal opacity were evaluated, including corneal degeneration (26/43), Reis-Bücklers corneal dystrophy (8/43), alkali burn (1/43) and corneal tumors (8/43). Based on AS-OCT images, all eyes showed abnormal hyper-reflective signals in the superficial cornea to less than one-third of the normal corneal thickness in the deepest corneal opacity. All 43 eyes underwent an SK procedure. In addition, 1 eye with alkali burns and 7 eyes with corneal tumors were combined with amniotic membrane transplantation. All eyes restored transparency without significant complications.

CONCLUSION

AS-OCT is a valuable method for objective preoperative and noninvasive assessments of anterior corneal opacities and is useful for guiding SK.

Sutureless superficial anterior lamellar keratoplasty for recurrent corneal haze after repeat excimer laser surface ablation

Background/Aims

To evaluate the 5-year outcomes of sutureless superficial anterior lamellar keratoplasty (SALK) in the treatment of surface ablation-related corneal haze recurring after phototherapeutic keratectomy (PTK).

Methods

Prospective interventional study at a tertiary referral centre in Forli, Italy. Ten consecutive eyes with corneal haze following photorefractive keratectomy, recurring after treatment with PTK with or without mitomycin C, undergoing sutureless SALK. Sutureless SALK was performed using a microkeratome in donor and recipient. Main outcome measures: best spectacle-corrected visual acuity (BSCVA), surgically induced astigmatism (SIA), rate of recurrence and complications.

Results

There were no intraoperative complications and there was no recurrence of haze in any eye postoperatively. BSCVA showed significant improvement at all postoperative time points. Mean preoperative visual acuity improved from 0.46 logMAR units (SD=0.12) to 0.12 (SD=0.12, p=0.0001) at 5 years. At 6 months, SIA was 2.50±1.04 with no further significant change at 5 years (2.53±1.39, p=0.95). There was no significant change in mean spherical equivalent and no significant difference between preoperative and postoperative astigmatism vector values at 5 years.

Conclusions

Sutureless SALK provides a useful treatment option in patients with recurrent haze after excimer laser treatment. It can eliminate haze recurrence for at least a period of 5 years and can improve BSCVA, although there may be significant SIA.

Femtosecond Laser-Assisted Lamellar Keratectomy for Corneal Opacities Secondary to Anterior Corneal Dystrophies: An Interventional Case Series

PURPOSE

To report results of femtosecond laser-assisted lamellar keratectomy (FLK) for corneal opacities secondary to anterior corneal dystrophies.

METHODS

Patients with a clinical diagnosis of Reis-Bücklers corneal dystrophy, granular corneal dystrophy, lattice corneal dystrophy, and macular corneal dystrophy were treated. FLK was performed to remove a central corneal free cap of 9.5 mm in diameter at a depth of 110 to 140 μm on which histological analysis was undertaken. Preoperative and postoperative refraction, best spectacle-corrected visual acuity, corneal topography results, and color photographs were recorded. Postoperative in vivo confocal microscopy of the cornea was performed. Changes in uncorrected visual acuity and best spectacle-corrected visual acuity, keratometry, refractive error, corneal irregularity, residual or recurrent central corneal opacities, and corneal haze were used to assess the outcome.

RESULTS

Eight eyes of 6 patients were treated. The clinical diagnosis was confirmed histologically in all cases. Visual acuity improved significantly from 0.49 ± 0.2 logMAR to 0.14 ± 0.13 logMAR after a mean follow-up of 29 ± 14 (range 8-54) months. Residual central stromal opacities were noted in 5 of 8 eyes immediately postoperatively. Clinically significant recurrence of disease was noted in 1 eye. Keratometry and refraction remained stable, and no further surgical intervention was needed. Patients with stromal corneal dystrophies had worse outcome than those with Reis-Bücklers corneal dystrophy.

CONCLUSIONS

In this case series, FLK provided both therapeutic and diagnostic intervention, delaying more invasive surgery. In vivo confocal microscopy showed signs of postoperative corneal stromal neuropathy.

Techniques, indications and complications of corneal debridement

The cornea is the most exposed surface of the eye and, as such, is vulnerable to external trauma and the risk of infection. Many corneal diseases alter shape, surface, and transparency and thus result in reduced vision. The external position of the cornea, however, lends itself to diagnostic and therapeutic maneuvers that are commonly performed and readily done in the clinic. More sophisticated techniques require the use of complex equipment such as excimer and femtosecond laser. Complications that develop from poor healing and/or secondary infection are best avoided with appropriate technique, antisepsis, and modification of wound healing. We review corneal debridement in the management of corneal disease.

Successful treatment of superficial corneal irregularity by lamellar keratectomy using the femtosecond laser

The authors report successful vision restoration after cataract surgery using a femtosecond laser in a patient with superficial corneal irregularity. A 62-year-old man with corneal irregularity and a cataract in the left eye was referred for treatment. The superficial corneal opacity causing the irregularity was mainly located within the superficial anterior cornea. To acquire a stable keratometric value, which is important for accurate calculation of intraocular lens power, lamellar keratectomy using a femtosecond laser (IntraLase; AMO, Irvine, CA) was performed to smooth the cornea surface. Postoperatively, corneal smoothness was restored and a stable keratometric value was acquired. Vision was improved with the expected refraction after cataract surgery. The femtosecond laser may be an effective surgical tool for patients with superficial corneal irregularity and cataracts.

Amniotic membrane transplant with superficial keratectomy in superficial corneal degenerations: efficacy in a rural population of north India

Aim:

To evaluate the applicability and efficacy of superficial keratectomy with transplantation of preserved amniotic membrane in superficial corneal degenerations in a rural population of Northern India in terms of visual improvement and surface regularization.

Settings:

Peripheral referral center in rural north India.

Materials and Methods:

This was a prospective non-comparative interventional case series where 24 eyes of 20 farmers from peripheral rural areas (M:F = 19:1) with visually significant superficial degenerative disorders (15 eyes with climatic droplet keratopathy one of which was associated with Salzmann nodular degeneration and nine eyes with band-shaped keratopathy) were subjected to amniotic membrane transplantation (single or multiple layer) combined with superficial keratectomy. Subjective and objective outcomes after surgery were evaluated and analyzed and statistical significance of the outcomes in various disorders was evaluated.

Results:

Eighty-eight per cent (21 eyes) had symptomatic relief from distressing preoperative symptoms while postoperative visual improvement by two or more lines was achieved in 23 eyes (96%) over a mean follow-up period of 26.8 ± 10.2 months. The surface irregularity present preoperatively was relieved in 23 cases while postoperative decline of vision with visually significant scarring was seen in one case (4%), which was labeled as failure.

Conclusions:

Amniotic membrane transplant with superficial keratectomy helped achieve subjective comfort, visual rehabilitation and clinical regularization of the corneal surface in superficial corneal degenerations during the mean followup of 26.8 ± 10.2 months in rural setups.

Phototherapeutische Keratektomie

Phototherapeutic keratectomy (PTK) involves the removal of corneal tissue with an excimer laser for therapeutic and/or functional purposes. In contrast to photorefractive keratectomy, a change in manifest refraction is not the primary goal of the treatment. The main indications are poor epithelial adherence, corneal opacities or an irregular corneal surface, as well as combinations of these. We describe the basic techniques, such as large area and focal PTK and provide recommendations on use of different masking agents. Numerous well established and rare clinical examples are described in terms of achievable PTK results.