Clinical manifestation and pathologic finding of unilateral acute hydrops after bilateral laser in situ keratomileusis

Management of acute corneal hydrops - Current perspectives

Acute corneal hydrops (ACH) is a rare but sight-threatening complication of corneal ectasias. We aim to review the current literature on etiopathogenesis, histology, role of ancillary investigations, management, and outcomes of ACH by classifying the various management strategies based on their site of action and the underlying mechanism. A review of the literature was conducted by searching the following databases: PubMed (United States National Library of Medicine), Embase (Reed Elsevier Properties SA), Web of Science (Thomson Reuters), and Scopus (Elsevier BV) till April 2023. The literature search used various combinations of the following keywords: acute corneal hydrops, keratoconus, ectasia, management, keratoplasty. Nine hundred eighty-three articles were identified based on the above searches. Case reports which did not add any new modality of treatment to the existing literature, articles unrelated to management, those with no full text available, and foreign-language articles with no translation available were excluded. Eventually, 75 relevant articles that pertained to the management of ACH were shortlisted and reviewed. Recent studies have described newer surgical interventions like full-thickness or pre-Descemetic sutures, thermokeratoplasty, and plasma injection that aim to close the posterior stromal break. Posterior lamellar keratoplasties act by replacing the posterior torn Descemet's membrane (DM), and early deep anterior lamellar keratoplasty (DALK) has been attempted to combine the correction of the anatomical defect and visual rehabilitation in a single surgery. These surgical interventions may help by reducing the scarring and increasing the number of patients who can be visually rehabilitated with contact lenses rather than keratoplasty.

Scleral Lens Visual Rehabilitation of Sequential Bilateral Corneal Hydrops With Post-LASIK Ectasia

ABSTRACT

This case report describes a unique presentation of bilateral sequential acute corneal hydrops that manifested several years after laser in situ keratomileusis. Initial management included anterior chamber perfluoropropane gas injection and corneal suturing. Longer-term visual rehabilitation involved the use of scleral lenses which significantly reduced lower- and higher-order ocular aberrations.

Compression Sutures to Treat Acute Hydrops in a Case of Bilateral Post-Laser In Situ Keratomileusis Ectasia

ABSTRACT

This a case report of acute hydrops with interface fluid syndrome in a patient with post-laser in situ keratomileusis (LASIK) ectasia treated with compression sutures. A patient with post-LASIK ectasia presented with acute hydrops and fluid accumulation in the LASIK flap-stromal interface sequentially in both eyes. Full thickness compression sutures were applied to appose the edges of the Descemet tear, and this resulted in a rapid resolution of stromal edema and interface fluid. The patient had best distance visual acuities of 20/40 and 20/60 at the last follow-up in the right and left eyes, respectively. Hydrops along with fluid in the interface needed early intervention to prevent complications such as epithelial ingrowth and interface haze. Compression sutures were useful in this case to help bridge the gap between the margins of Descemet tear, hastening the resolution of stromal edema and interface fluid.

Management of acute corneal hydrops after laser in situ keratomileusis

A 43-year-old man developed acute corneal hydrops after laser in situ keratomileusis (LASIK). A persistently fluid-filled interface between the corneal flap and stroma (without flap dehiscence or wound leakage) did not respond to the conservative treatment. To avoid keratoplasty, the subflap fluid was drained by an air injection into the anterior chamber; the surgery also included suturing of the corneal flap and stroma. The corrected distance visual acuity improved rapidly after resolution of the fluid-filled interface and corneal stromal edema, and no leakage was observed. Thus, a minimally invasive surgery to drain the subflap fluid by an air injection was effective for treating a persistently fluid-filled interface in a case of acute corneal hydrops after LASIK.

Spontaneous Resolution of Acute Corneal Hydrops in a Patient With Post-LASIK Ectasia

PURPOSE

To describe a case of acute corneal hydrops in a patient with corneal ectasia after laser in situ keratomileusis (LASIK).

METHODS

An observational study presenting clinical, slit-lamp, and optical coherence tomographic findings.

RESULTS

A 66-year-old man with a history of moderate myopic astigmatism presented with a sudden loss of vision in his left eye 11 years after undergoing LASIK. He underwent a single enhancement in his left eye and was subsequently diagnosed with ectasia 9 years later. Slit-lamp examination demonstrated a small tear in the Descemet membrane with a large fluid-filled cleft separating the LASIK flap and extending to the flap edge. Because no aqueous humor leakage was detected, the patient was managed conservatively with eventual resolution of the fluid-filled cleft and return of 20/30 visual acuity.

CONCLUSIONS

Acute corneal hydrops is a rare complication of post-LASIK corneal ectasia. In the absence of flap dehiscence and wound leak, such patients may be managed with simple observation.

Meta-analysis of Pentacam vs. ultrasound pachymetry in central corneal thickness measurement in normal, post-LASIK or PRK, and keratoconic or keratoconus-suspect eyes

BACKGROUND

The aim of this meta-analysis is to evaluate the central corneal thickness (CCT) measurement differences between Pentacam (Oculus Inc., Germany) and Ultrasound Pachymetry (USP) in normal (unoperated eyes , myopic and astigmatic eyes without corneal disease or topographic irregularity), after laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK), and keratoconic or keratoconus suspected eyes. We assess whether Pentacam and USP have similar CCT differences in normal, thinner corneas after LASIK or PRK procedures, and kerotoconic or keratoconus suspected eyes.

METHODS

Data sources, including PubMed, Medline, EMBASE, and Cochrane Central Registry of Controlled Trials on the Cochrane Library, were searched to find the relevant studies. Primary outcome measures were CCT measurement between Pentacam and USP. Three groups of eyes were analyzed: normal; LASIK or PRK eyes; and keratoconus suspected or keratoconic eyes.

RESULTS

Nineteen studies describing 1,908 eyes were enrolled in the normal group. Pentacam results were 1.47 μm ,95 % confidence interval (CI) -2.32 to 5.27, higher than USP without statistically significant difference (P = 0.45). Nine studies with total 539 eyes were included in the corneas after LASIK or PRK. The mean difference in the CCT measurement with Pentacam and ultrasound pachymetry was 1.03 μm, with the 95 % CI -3.36 to 5.42, there was no statistically difference (P = 0.64). Four studies with a total of 185 eyes were included in the keratoconic eyes or keratoconus-suspect group, however,the mean difference was -6.33 μm (95 % CI -9.17 to-3.49), which was statistically different between Pentacam and ultrasound pachymetry in the CCT measurement (P < 0.0001).

CONCLUSIONS

Pentacam offers similar CCT results to ultrasound pachymetry in normal eyes, thinner corneas after LASIK or PRK procedures. However, in keratoconic or keratoconus-suspect eyes, Pentacam slightly underestimates the central corneal thickness than does ultrasound pachymetry, which may result from the difficulty in fixation of keratoconic eyes, misalignment of Pentacam and the variation of ultrasonic velocity due to the histological deformation.

Risk Assessment for Ectasia after Corneal Refractive Surgery

PURPOSE

To analyze the epidemiologic features of ectasia after excimer laser corneal refractive surgery, to identify risk factors for its development, and to devise a screening strategy to minimize its occurrence.

DESIGN

Retrospective comparative and case-control study.

PARTICIPANTS

All cases of ectasia after excimer laser corneal refractive surgery published in the English language with adequate information available through December 2005, unpublished cases seeking treatment at the authors' institution from 1998 through 2005, and a contemporaneous control group who underwent uneventful LASIK and experienced a normal postoperative course.

METHODS

Evaluation of preoperative characteristics, including patient age, gender, spherical equivalent refraction, pachymetry, and topographic patterns; perioperative characteristics, including type of surgery performed, flap thickness, ablation depth, and residual stromal bed (RSB) thickness; and postoperative characteristics including time to onset of ectasia.

MAIN OUTCOME MEASURES

Development of postoperative corneal ectasia.

RESULTS

There were 171 ectasia cases, including 158 published cases and 13 unpublished cases evaluated at the authors' institution. Ectasia occurred after LASIK in 164 cases (95.9%) and after photorefractive keratectomy (PRK) in 7 cases (4.1%). Compared with controls, more ectasia cases had abnormal preoperative topographies (35.7% vs. 0%; P<1.0x10(-15)), were significantly younger (34.4 vs. 40.0 years; P<1.0x10(-7)), were more myopic (-8.53 vs. -5.09 diopters; P<1.0x10(-7)), had thinner corneas before surgery (521.0 vs. 546.5 microm; P<1.0x10(-7)), and had less RSB thickness (256.3 vs. 317.3 microm; P<1.0x10(-10)). Based on subgroup logistic regression analysis, abnormal topography was the most significant factor that discriminated cases from controls, followed by RSB thickness, age, and preoperative corneal thickness, in that order. A risk factor stratification scale was created, taking all recognized risk factors into account in a weighted fashion. This model had a specificity of 91% and a sensitivity of 96% in this series.

CONCLUSIONS

A quantitative method can be used to identify eyes at risk for developing ectasia after LASIK that, if validated, represents a significant improvement over current screening strategies.

Interface Fluid Syndrome in Human Eye Bank Corneas after LASIK

PURPOSE

To evaluate the effects of corneal edema on human donor corneas that had previous LASIK using a laboratory model with histologic and ultrastructural correlations.

DESIGN

Experimental study.

PARTICIPANTS

Thirty human eye bank corneas from 15 donors (mean age +/- standard deviation, 49.9+/-8.9 years) who had had previous LASIK surgery (2-8 years before death).

METHODS

The corneas were mounted in an artificial anterior chamber and the corneal endothelium was perfused for up to 5.0 hours with 0.9% saline solution (endothelial cell damage group) or BSS Plus at a pressure of 15 mmHg (control group), or BSS Plus at a pressure of 55 mmHg (high-pressure group). The corneas were evaluated by confocal and specular microscopy before, during, and at the end of the experimental period. Subsequently, the specimens were evaluated by light and electron microscopy.

MAIN OUTCOME MEASURES

Corneal thickness, reflectivity, histology, and ultrastructure.

RESULTS

Endothelial cell damage resulted in an increased (141.5+/-38.8 microm) total corneal thickness relative to controls (52.3+/-33.7 microm), whereas high pressure resulted in a decreased thickness (24.8+/-14.1 microm) relative to controls. This ultimately was due to swelling of the LASIK interface in both groups and swelling of the residual stromal bed (RSB) in the endothelial cell damage group or compression of the RSB and, possibly, the flap in the high-pressure group. A significant increase in corneal reflectivity at the LASIK interface occurred in both groups, primarily due to varying degrees of fluid accumulation and associated hydropic keratocyte degeneration, as well as increased corneal reflectivity in the RSB only in the endothelial cell damage group.

CONCLUSIONS

After LASIK surgery, edematous corneas preferentially hydrate and swell in the paracentral and central interface wound, commonly resulting in a hazy corneal appearance primarily due to keratocyte hydropic degeneration. More severe corneal edema is characterized by the formation of an optically empty space corresponding to an interface fluid pocket. The spectrum of interface fluid syndrome can be described in 3 stages.

Acute corneal hydrops with perforation after LASIK-associated keratectasia

Herein a case of acute corneal hydrops with perforation in keratectasia 9 years after bilateral laser in situ keratomileusis is presented. A 27-year-old man presented with right eye sudden loss of vision. Right eye best-corrected visual acuity was counting fingers. Left eye best-corrected visual acuity was 6/9. Right eye slit-lamp examination revealed diffuse corneal oedema with central epithelial cystic change. The interface between the flap and residual stroma was open and filled with fluid. This separation extended nearly to the flap margin. Shallow anterior chamber and aqueous leakage were noted the following day. An emergency penetrating keratoplasty was performed to the right eye. Histopathology of corneal button revealed reactive keratocytes with irregular, wrinkled collagen formation over ablated stroma. Marked stromal oedema was observed. Twelve months after corneal transplantation, vision improved to 6/6 with correction in the right eye.