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

Phototherapeutic keratectomy versus epithelial debridement combined with anterior stromal puncture or diamond-dusted burr for treatment of recurrent corneal erosions

OBJECTIVE

To compare outcomes of phototherapeutic keratectomy (PTK) versus epithelial debridement combined with anterior stromal puncture (ASP) or diamond burr for the treatment of recurrent corneal erosions (RCES) in a large tertiary centre.

METHODS

Patients with a diagnosis of RCES secondary to trauma or epithelial basement membrane dystrophy who underwent a surgical procedure between 2009 and 2019 were included in the study. The following data were collected: demographics, ocular history, prior medical treatment, ocular surgeries, intervention, complete epithelialization at postoperative week 1, recurrences, and complications. Recurrence was defined as either an objective finding of a corneal epithelial defect or symptoms suggestive of recurrent epithelial erosion on history. Recurrence rate and time to epithelialization were compared between groups.

RESULTS

A total of 97 eyes (73 patients) were included in the study. Mean patient age was 51 ± 16.1 years, and mean follow-up was 474 days. RCES was secondary to epithelial basement membrane dystrophy in 80% (n = 78 of 97), trauma (15%, n = 15 of 97), or idiopathic (4%, n = 4 of 97). Epithelial debridement with ASP was performed in 34 eyes (35%), diamond burr in 33 eyes (33%), and PTK in 30 eyes (31%). Compared with epithelial debridement with ASP (recurrence 29.4%), the recurrence rate was significantly lower for both the diamond burr (9.1%, p = 0.031) and PTK groups (10%, p = 0.048). The diamond burr and PTK groups also had a significantly higher rate of complete epithelialization at 1 week (p < 0.05).

CONCLUSION

Compared with epithelial debridement with ASP, diamond burr and PTK have significantly lower rates of recurrence and time to epithelialization and may be considered first for surgical management of RCES.

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.

[Epithelial basement membrane dystrophy diagnosed following LASIK surgery]

A 48-year-old woman with no significant past history underwent bilateral simultaneous laser in situ keratomileusis for correction of her myopia. On the tenth postoperative day, the patient complained of visual decrease and photophobia. Slit lamp exam showed corneal epithelial irregularities. Confocal microscopy was performed and revealed a characteristic appearance of epithelial basement membrane dystrophy (EBMD). The patient was successfully treated with artificial tears and autologous serum eyedrops. EBMD may be missed before LASIK surgery, even after a careful pre-operative examination. Exacerbation of EBMD after LASIK surgery is rare. It should be considered when unexplained corneal epithelial defects or irregularities occur following LASIK. Confocal microscopy is very useful to confirm the diagnosis.

Results of Phototherapeutic Keratectomy in the Management of Flap Striae after LASIK before and after Developing a Standardized Protocol

OBJECTIVE

To evaluate the efficacy and safety of phototherapeutic keratectomy (PTK) for treatment of striae in LASIK flaps.

DESIGN

Retrospective consecutive series.

PARTICIPANTS

Forty-seven eyes of 44 patients with flap striae after LASIK with reduced best-corrected visual acuity (VA) or visual symptoms with at least 3 months' follow-up (consecutive cases from January 2001 to May 2004).

INTERVENTION

Transepithelial PTK.

MAIN OUTCOME MEASURES

Uncorrected VA (UCVA), best spectacle-corrected VA (BSCVA), resolution or reduction of preoperative symptoms, and corneal haze.

RESULTS

Mean UCVA and BSCVA improved from 20/43 and 20/29 to 20/33 and 20/23, respectively. Five eyes (10%) developed 1+ haze and 14 eyes (30%) developed trace haze, generally peaking at 1 to 2 months postoperatively. No visual symptoms or loss of acuity were attributable to haze. A mean hyperopic shift of +0.80 diopters (D) occurred after PTK treatment. Development of a standardized protocol significantly reduced the variability of the refractive shift after PTK (P = 0.003). Results were stable in up to 2 years of follow-up.

CONCLUSIONS

Phototherapeutic keratectomy treatment of LASIK flaps is well tolerated, with stable outcomes and minimal complications. A standardized treatment protocol reduced postoperative refractive variability.

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.

Safety, efficacy, and stability indices of LASEK correction in moderate myopia and astigmatism

PURPOSE

To evaluate the visual outcomes and complications in low to moderate levels of myopia and astigmatism treated with laser-assisted subepithelial keratectomy (LASEK) with a focus on postoperative recovery.

SETTING

Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA.

METHODS

A retrospective analysis of a case series of eyes treated with LASEK from 1996 to July 2002 with a follow-up of 2 years was performed. The LASEK technique involved creating an epithelial flap with 25 to 45 seconds of exposure to 20% alcohol, ablating the corneal surface using 3 different excimer lasers and nomogram adjustment, and repositioning the flap and applying a bandage contact lens. The main outcome measures were uncorrected visual acuity (UCVA), efficacy index, manifest refraction, best spectacle-corrected visual acuity (BSCVA), safety index, retreatment rate, and complications.

RESULTS

One hundred seventy-one eyes (85 right eyes and 86 left eyes) of 105 patients were studied. Preoperatively, the mean spherical equivalent was -2.99 diopters (D) +/- 1.43 (SD) (range -0.38 to -7.75 D) and the mean cylinder, -0.78 +/- 0.73 D. The UCVA ranged from 20/800 to 20/32, and the BSCVA ranged from 20/63 to 20/16; the median was 20/20. One week postoperatively, 96% of eyes had a UCVA of 20/40 or better but definitive visual recovery took more than 4 weeks in some eyes. Approximately 95% of eyes were within +/-1.0 D of emmetropia after 4 to 52 weeks; the remaining 5% did not show major deviations. At 4 to 52 weeks, only 1 eye was overcorrected by more than 1.0 D of manifest refraction. The safety index remained close to 1.0 for the follow-up after 4 weeks. The efficacy index displayed a plateau at 0.9 from 1 month to 1 year. No serious complication (including recurrent erosion syndrome) was encountered. The mean follow-up was 31 weeks, and the retreatment rate was 2.9% up to 2 years of follow-up.

CONCLUSIONS

The long-term safety and effectiveness of LASEK for the correction of low to moderate myopia and astigmatism were demonstrated. The treatment effect stabilized after 4 weeks.

Keratocyte activation and inflammation in diffuse lamellar keratitis after formation of an epithelial defect

PURPOSE

To examine the inflammatory reaction in acute or late-onset post-laser in situ keratomileusis (LASIK) diffuse lamellar keratitis (DLK) associated with an epithelial defect.

SETTING

Department of Ophthalmology, Helsinki University Central Hospital, Helsinki, Finland.

METHODS

Six consecutive LASIK patients presented with stage 2 to 3 unilateral DLK 1 to 4 days after formation of an epithelial detachment (intraoperatively or up to 19 months postoperatively). Five corneas of 5 DLK patients, 1 eye twice, were examined by corneal in vivo confocal microscopy 1 to 8 days after the appearance of the epithelial defect. Confocal microscopy of conjunctival venules was performed in 2 of 6 DLK patients to quantify leukocyte rolling and extravasation. Corneas of 5 patients and conjunctival venules of 4 patients who had uneventful LASIK served as controls.

RESULTS

Two of the 4 patients examined 0 to 1 day after the onset of DLK presented with small objects, presumably inflammatory cells (diameter 6.0 to 10.0 microm), in the LASIK flap interface. A third patient examined 1 day after the onset of DLK had larger objects (approximately 13.0 microm in diameter) in the interface. Three other cases (1 to 7 days after the onset of DLK) showed changes typical of keratocyte activation and altered extracellular matrix. All cases healed completely following treatment with steroids. Control LASIK subjects showed some keratocyte activation on day 5.

CONCLUSIONS

Neither uneventful LASIK nor DLK induced an inflammatory reaction displaying leukocyte rolling in conjunctival venules or extravasation into the conjunctival stroma. Diffuse lamellar keratitis related to an epithelial defect does not always lead to the appearance of inflammatory cells in the flap interface. The corneal manifestations of epithelial defect-related DLK may originate from sterile epithelial-stromal or inflammatory cell-stromal cell interactions, leading to alteration of the keratocyte phenotype.