Acute Hydrops After Deep Anterior Lamellar Keratoplasty in a Patient With Keratoconus

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.

Evaluating the safety and efficacy of compression sutures with intracameral perfluoropropane (C3F8) in the management of acute corneal hydrops

BACKGROUND

To evaluate the safety and efficacy of using corneal compression sutures with intracameral perfluoropropane (C3F8) in patients presenting with acute corneal hydrops in ectatic disorders.

METHODS

A retrospective analysis was done for 43 eyes of patients of acute corneal hydrops, managed using a combination of intracameral 14% C3F8 and full-thickness compression sutures. Time for resolution of edema, corneal thickness (CT) change on anterior segment ocular coherence tomography (ASOCT), and visual outcomes were assessed.

RESULTS

Corneal edema resolved with a mean duration of 14.8 ± 3.5 days (range 10-21). The mean CT on ASOCT decreased from a mean of 1437 µm (689-2770 µm) preoperatively to 543 µm (434 -66 µm) on the complete resolution of corneal edema.

CONCLUSION

Our results suggest that full-thickness compression sutures and intracameral C3F8 injection can restore the imperviousness of posterior stroma. This technique appears to be a safe and effective technique for faster resolution of corneal edema post hydrops.

Mechanisms for acute corneal hydrops and perforation

Acute corneal hydrops (ACH) and perforation in corneal thinning diseases are the consequences of exposure to distending intraocular pressure (IOP) forces that are in excess of corneal resistance to them. Apart from thinning, resistance to these forces may be reduced by disease-related tissue changes, such as corneal scarring, which could lower resistance to IOP. Eye rubbing trauma has sometimes been found to be associated with ACH and perforation. This association is not surprising given that the combination of rubbing-related mechanical tissue trauma and the associated increased distending stress of higher IOP seem likely to increase the risk of complications. Many cases of ACH and perforation are described as spontaneous, but this classification may be the consequence of not considering the multiple potential mechanisms for IOP elevation such as coughing, sneezing, nose blowing, and sneeze suppression in addition to those related to eye rubbing/wiping/massaging/touching as well as changes in body orientation, strenuous exercise, and wearing swimming goggles for example. Classification of ACH or perforation as spontaneous may lead patients to assume that nothing can be done to avoid these complications. Patients with corneal thinning diseases who are counseled regarding the potential precipitating mechanisms for IOP elevation will have the opportunity of reducing exposure to them and the risk of the associated complications. In addition, when ACH or perforation occur, faster resolution of edema and wound healing may depend on reducing potentially exacerbating exposures to mechanisms for IOP elevation.

Enzyme-assisted deep anterior lamellar keratoplasty-a new method of lamellar dissection-a wetlab-based pilot study

PURPOSE

To explore the safety of a new technique of lamellar dissection, using enzymatic digestion of the corneal stroma and extracellular matrix.

METHODS

This was a wetlab-based pilot study of hyaluronidase and trypsin-assisted deep anterior lamellar keratoplasty (DALK) in cadaveric human corneal tissue. Enzyme-assisted DALK was performed on 17 tissues. These underwent histologic analysis using a pneumatic dissection specimen as control. Rates of perforation and Descemet membrane (DM) exposure were recorded by clinical observation and by optical coherence tomography in selected cases. Where possible, pre- and postsurgical endothelial cell counts were obtained via specular microscopy. Two tissues from the same donor were halved, with each half soaked in a different solution (Optisol, balanced salt solution, hyaluronidase, and trypsin) for 13.5 hours to observe maximal effect.

RESULTS

Successful exposure of DM was achieved in 8 specimens. In the remaining 9, manual dissection was possible to a residual depth of 25 to 90 μm where measured with optical coherence tomography. Three tissues had perforation of DM, all via manual maneuvers. No deleterious effects on residual host tissue were observed by light microscopy with no significant rates of endothelial cell loss in 8 tissues in which a predissection cell count was obtainable. The 2 enzymes had differing effects on soaked specimens that were reflected intraoperatively.

CONCLUSION

Preliminary results of this ex vivo study are encouraging that enzymolysis may represent an effective innovation in DALK surgery with an acceptable safety profile. Further studies are required to refine the technique and application of the enzymes in vivo.