Abstract:Assessing the intraocular pressure is a difficult but crucial task in the follow-up of patients that have undergone penetrating keratoplasty. Early recognition of elevated intraocular pressure and/or glaucoma and establishment of the appropriate treatment is essential to ensure the best possible visual outcome for patients dealing with this feared complication. Although Goldmann applanation tonometry is still the gold standard for measuring the intraocular pressure, its limitations in postkeratoplasty eyes, du… Show more
“…This is because, after penetrating keratoplasty, it is difficult to assess the severity and progression of glaucoma using conventional methods (clinical examination of the optic nerve and of the nerve fiber layers, automated perimetry, and optical coherence tomography) because of the partial or total opacification of the corneal graft and a low visual acuity. In these situations, IOP is one of the few objective parameters that can be used for follow-up, although even IOP measurement is subject to many sources of error [14]. Our results are comparable to those of other studies that evaluate the IOP-lowering efficiency of MP-TSCPC, both in patients post PK and in other clinical settings.…”
The main objective of the article was to assess the surgical outcome of micropulse transscleral cyclophotocoagulation in patients presenting with glaucoma after penetrating keratoplasty. We conducted a retrospective study that included 26 eyes of 26 patients who presented with glaucoma after penetrating keratoplasty, and who were treated using micropulse transscleral cyclophotocoagulation between January 2017 and December 2020. The surgeries were performed using the Iridex Cyclo G6 MicroPulse P3 Probe. The intraocular pressure, mean number of antiglaucoma medications, visual acuity, corneal status, and postoperative complications were analyzed. The minimum follow-up period was 12 months. The success rate after 12 months was 76.9%. The baseline median intraocular pressure was 29 mm Hg and decreased to 18 mm Hg after 12 months. The median number of antiglaucoma medications was also reduced from three preoperatively to one after one year. In seven cases (29.92%), the visual acuity decreased and, in four cases (15.38%), the corneal graft was not transparent. We concluded that micropulse transscleral cyclophotocoagulation is an effective and safe method for the treatment of glaucoma after penetrating keratoplasty.
“…This is because, after penetrating keratoplasty, it is difficult to assess the severity and progression of glaucoma using conventional methods (clinical examination of the optic nerve and of the nerve fiber layers, automated perimetry, and optical coherence tomography) because of the partial or total opacification of the corneal graft and a low visual acuity. In these situations, IOP is one of the few objective parameters that can be used for follow-up, although even IOP measurement is subject to many sources of error [14]. Our results are comparable to those of other studies that evaluate the IOP-lowering efficiency of MP-TSCPC, both in patients post PK and in other clinical settings.…”
The main objective of the article was to assess the surgical outcome of micropulse transscleral cyclophotocoagulation in patients presenting with glaucoma after penetrating keratoplasty. We conducted a retrospective study that included 26 eyes of 26 patients who presented with glaucoma after penetrating keratoplasty, and who were treated using micropulse transscleral cyclophotocoagulation between January 2017 and December 2020. The surgeries were performed using the Iridex Cyclo G6 MicroPulse P3 Probe. The intraocular pressure, mean number of antiglaucoma medications, visual acuity, corneal status, and postoperative complications were analyzed. The minimum follow-up period was 12 months. The success rate after 12 months was 76.9%. The baseline median intraocular pressure was 29 mm Hg and decreased to 18 mm Hg after 12 months. The median number of antiglaucoma medications was also reduced from three preoperatively to one after one year. In seven cases (29.92%), the visual acuity decreased and, in four cases (15.38%), the corneal graft was not transparent. We concluded that micropulse transscleral cyclophotocoagulation is an effective and safe method for the treatment of glaucoma after penetrating keratoplasty.
“…8 c. On the contrary, for a misaligned button, the suture tensions could vary based on their location, as illustrated in Fig. 8 d, resulting in post-PK complications in refractive errors 44 and intraocular pressure measurement 45 , 46 as reported in the literature. Figure 8 ( a ) Representation of post PK cornea with sutures, ( b ) fracture toughness in trouser tear mode mapped onto the human cornea, ( c ) ideal PK condition with sutures, and ( d ) when the location of PK is offset in one direction.…”
Fracture toughness of the human cornea is one of the critical parameters in suture-involved corneal surgeries and the development of bioengineered mimetics of the human cornea. The present article systematically studied the fracture characteristics of the human cornea to evaluate its resistance to tear in the opening (Mode-I) and trouser tear mode (Mode-III). Tear experiments reveal the dependency of the fracture behavior on the notch size and its location created in the corneal specimens. The findings indicate lamellar tear and collagen fiber pull-out as a failure mechanism in trouser tear and opening mode tests, respectively. Experimental results have shown a localized variation of tear behavior in trouser tear mode and indicated an increasing resistance to tear from the corneal center to the periphery. This article demonstrated the complications of evaluating fracture toughness in opening mode and showed that the limbus was weaker than the cornea and sclera against tearing. The overall outcomes of the present study help in designing experiments to understand the toughness of the diseased tissues, understanding the effect of the suturing location and donor placement, and creating numerical models to study parameters affecting corneal replacement surgery.
“…Pascal dynamic contour tonometry (PDCT), Tono-Pen, ocular response analyzer (ORA), and the iCare all appear to correlate well with, though tend to overestimate, GAT measurements in post-penetrating keratoplasty eyes [23]. PDCT has shown to be minimally affected by central corneal thickness (CCT) or corneal astigmatism, the TonoPen has the advantage of requiring only a small area of contact with the cornea, while newer devices such as ORA take into account altered corneal biomechanics [23]. Alternatively, the iCare may be useful for IOP measurement in postpenetrating keratoplasty eyes with corneal edema [24], likely because of the correlation between iCare with CCT and corneal curvature [23].…”
Section: Assessing Intraocular Pressure In Penetrating Keratoplasty Eyesmentioning
confidence: 99%
“…Furthermore, when the graft is edematous, the IOP may be artificially lowered, potentially leading to false reassurance [22 ]. Pascal dynamic contour tonometry (PDCT), Tono-Pen, ocular response analyzer (ORA), and the iCare all appear to correlate well with, though tend to overestimate, GAT measurements in postpenetrating keratoplasty eyes [23]. PDCT has shown to be minimally affected by central corneal thickness (CCT) or corneal astigmatism, the TonoPen has the advantage of requiring only a small area of contact with the cornea, while newer devices such as ORA take into account altered corneal biomechanics [23].…”
Section: Assessing Intraocular Pressure In Penetrating Keratoplasty Eyesmentioning
Purpose of reviewAdvances in surgical techniques and postoperative care have significantly improved rates of short-term complications following keratoplasty; however, glaucoma remains a highly prevalent long-term and potentially devastating complication for postkeratoplasty patients. In this review, we provide an overview of recent literature on glaucoma management in patients who have undergone penetrating keratoplasty or the Boston keratoprosthesis type I (KPro) implantation.Recent findingsNew research suggests an inflammatory cause underlying glaucoma following KPro. Accurate IOP measurement is difficult in patients postkeratoplasty; study of objective techniques such as PDCT or Tono-Pen in penetrating keratoplasty eyes and trans-palpebral Diaton tonometry in KPro eyes have shown promising results. Early glaucoma surgical intervention should be considered for patients undergoing penetrating keratoplasty and KPro.SummaryPatients who have undergone penetrating keratoplasty or implantation of the Boston keratoprosthesis type I should be monitored frequently for elevated intraocular pressure and for other signs of glaucomatous optic nerve damage. Intraocular pressure elevation should be treated promptly either medically or surgically while minimizing risk to the corneal graft. Further research into inflammatory causes and other treatment modalities is promising for the long-term visual success in these patients.
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