Incidence and risk factors for post-penetrating keratoplasty glaucoma

Purpose: To carry out a prospective study to analyze the incidence and various preoperative, intraoperative, and postoperative risk factors for the development of PPKG. Methods: A total of 207 patients were analyzed prospectively, who were operated for penetrating keratoplasty (PK) in a tertiary eye care hospital between the time period of August 1, 2017 and February 28, 2018 and were followed up till the sixth month. Each patient was analyzed at every visit to determine the factors responsible for post?keratoplasty glaucoma. Results: Out of 207 eyes, post?PK glaucoma developed in 84 cases, which yielded an incidence of 41%. Incidence of PPKG (Post PK glaucoma) in various conditions was as follows: in repeat PK 62%, in perforated corneal ulcer 33%, in nonperforated corneal ulcer 29%, in corneal scar including adherent leukoma 37.2%, and in pseudophakic bullous keratopathy and aphakic bullous keratopathy, 14% and 80%, respectively. In age? and sex?adjusted multivariate analysis, the significant risk factors were age (P?value? 0.006), presence of PAS (P?value 0.001), and fellow eye glaucoma (P?value 0.04). Aphakia and combined surgery were not found to be significant. Conclusion: Our study recommends a meticulous examination of the fellow eye to assess the presence of glaucoma as it can increase the suspicion of glaucoma in the eye to be operated. The presence of PAS and age are important risk factors for developing PPKG. The risk of developing PPKG increases exponentially as the number of risk factors increases, but the presence of more than three risk factors does not add to the development of PPKG

Collagen cross-linking in thin corneas.

Collagen cross-linking (CXL) has become the standard of care for progressive keratoconus, after numerous clinical studies have established its efficacy and safety in suitably selected eyes. The standard protocol is applicable in eyes which have a minimum corneal thickness of 400 μm after epithelial debridement. This prerequisite was stipulated to protect the corneal endothelium and intraocular tissues from the deleterious effect of ultraviolet-A (UVA) radiation. However, patients with keratoconus often present with corneal thickness of less than 400 μm and could have otherwise benefited from this procedure. A few modifications of the standard procedure have been suggested to benefit these patients without a compromise in safety. Transepithelial cross-linking, pachymetry-guided epithelial debridement before cross-linking, and the use of hypoosmolar riboflavin are some of the techniques that have been attempted. Although clinical data is limited at the present time, these techniques are worth considering in patients with thin corneas. Further studies are needed to scientifically establish their efficacy and safety.