Modified technique addresses acute corneal hydrops
The technique can be performed as a primary procedure and offers good results, safety and predictability.
Acute corneal hydrops occurs secondary to a tear in the Descemet’s membrane and results from aqueous seepage into the stroma, forming fluid clefts.
Conventionally, this is managed medically with compression sutures or with intracameral gas or air injections followed in many cases by a secondary pre-Descemetic deep anterior lamellar keratoplasty at a later stage. However, this strategy results in healing with the formation of a scar, with the location of the scar depending on the area of the Descemetic tear. If the scar occurs in the visual axis, it can result in deterioration of vision and necessitate penetrating keratoplasty, thereby exposing the patient to the risks associated with PK, such as rejection and secondary graft failure. Following conventional management, although some patients may undergo a secondary pre-Descemetic DALK at a later stage, this is possible only if the scarring is outside the visual axis. This approach is also associated with the morbidity and expense of a second surgery. Although contact lenses may fit better after resolution of hydrops, the patient can wear them only for limited time per day and generally continues to have poor glass tolerance and poor vision during the remaining hours of the day. It also exposes patients to the risks associated with contact lens wear. Patients who have suboptimal contact lens fit, apical touch and scarring will require special optical lenses, which are expensive.
The following modified technique, proposed by one of us (Jacob), can be performed as a primary procedure for the treatment of acute hydrops and gives excellent results as well as safety and predictability.
Surgery with this technique in the acute stage immediately after the occurrence of hydrops prevents healing by stromal scarring. It provides anatomical correction of ectasia and thinning. It also simultaneously targets multiple pathologies that can be associated with advanced ectasia and results in topographic, pachymetric, biomechanical, visual and structural improvement while allowing decreased contact lens dependence. It provides early and rapid visual rehabilitation, early anatomic rehabilitation and optical correction by regaining corneal structure and transparency. It closes the Descemetic break while still maintaining transparency over the area of the break. As the host Descemetic membrane and endothelium are retained and scarring over the visual axis is avoided, it avoids the risks associated with PK such as rejection and secondary graft failure. It has the advantages of single-stage surgery and avoids costs and morbidities associated with two surgeries (Figures 1 to 3).
Surgery modifications include using a 26-gauge needle with the bevel bent upward instead of down in order to avoid pressure buildup from air that is injected downward. The needle is directed tangentially away from the break, and only small aliquots of air are injected slowly at multiple sites, again to avoid large pressure buildups. Air is injected only to create tissue emphysema, which is then used as a guide for the depth of dissection. Manual deep dissection is then proceeded with centripetally using a blunt dissector, leaving the area of the Descemetic tear or the break for last. Deeper dissection can then be performed after gentle re-induction of emphysema or by using Melles technique of optical recognition. Minimal stroma is intentionally retained above the Descemetic tear to prevent the anterior chamber from collapsing. Finally, the donor graft with Descemet’s membrane and endothelium stripped is sutured onto the host bed, and the Descemet’s tear is tamponaded with air in the anterior chamber. In eyes with extensive edema or with thin residual stroma, the initial groove can be created by manually deepening an ink trephine mark with a sharp crescent blade.
This modified technique can also be used in keratoglobus and pellucid marginal degeneration but with a tucked-in lamellar keratoplasty instead.
- Jacob S, et al. Cornea. 2018;doi:10.1097/ICO.0000000000001693.
- Jacob S. Primary pre descemetic DALK for acute hydrops Soosan Jacob with audio. https://www.youtube.com/watch?v=5ZeAXOmVDJw. Published June 14, 2018.
- For more information:
- Amar Agarwal, MS, FRCS, FRCOphth, is director of Dr. Agarwal’s Eye Hospital and Eye Research Centre. Agarwal is the author of several books published by SLACK Incorporated, publisher of Ocular Surgery News, including Phaco Nightmares: Conquering Cataract Catastrophes, Bimanual Phaco: Mastering the Phakonit/MICS Technique, Dry Eye: A Practical Guide to Ocular Surface Disorders and Stem Cell Surgery and Presbyopia: A Surgical Textbook. He can be reached at 19 Cathedral Road, Chennai 600 086, India; email: firstname.lastname@example.org; website: www.dragarwal.com.