Assessment of Tactile Sensitivity Threshold Using Cochet-Bonnet Esthesiometer and Semmes-Weinstein Monofilaments and Their Use in Corneal Neurotization.

PURPOSE: Although the Cochet-Bonnet esthesiometer (CBE) measures corneal sensitivity, it has heretofore only been tested on the index pulp. Tactile skin sensitivity thresholds are measured with Semmes-Weinstein monofilaments (SWM). This study measured skin sensitivity thresholds in healthy individuals using CBE and SWM, and compared both instruments in territories involved in corneal neurotization. METHODS: Overall, 27 healthy individuals were tested by a single examiner at 9 territories on the face, neck, forearm, and leg, using 20-thread SWM and CBE with a diameter of 0.12 mm. Both sides were tested. Thresholds were compared for both instruments and between the different territories using Bayesian methods. RESULTS: Mean sensitivity levels for SWM ranged from 0.010 to 1.128 g, while mean sensitivity levels for CBE ranged from 0.006 to 0.122 g. Thresholds measured with SWM were significantly higher than with CBE. Both instruments demonstrated higher thresholds in the leg territory than the forearm. However, the forearm presented higher thresholds than the head territories. No significant differences were found between the head territories themselves. Overall, right-side territories exhibited lower thresholds than left-side territories. CONCLUSIONS: We have reported the first mapping of skin sensitivity thresholds using CBE. Thresholds measured with CBE and SWM were coherent. The use of CBE on the skin is particularly relevant to the field of corneal neurotization.

Retinal microvascular changes in unilateral functional amblyopia detected by oct-angiography and follow-up during treatment.

OBJECTIVE: To evaluate the macular microvascular changes using optical coherence tomographic angiography (OCT-A) in children with unilateral amblyopia and their reversibility during treatment. METHODS: Patients with unilateral strabismic or anisometropic amblyopia or residual amblyopia from early congenital cataract surgery, examined between October 2019 and March 2021, were included. Vessel density and perfusion density in the superficial capillary plexus and area, perimeter and circularity of the foveal avascular zone (FAZ) were analysed using OCT-A in amblyopic eyes, contralateral eyes and control group healthy eyes. Correlation analyses between the microvascular parameters and the visual acuity were performed. In a pilot study on a few patients from the amblyopic cohort, longitudinal follow-up during treatment was also performed. RESULTS: A total of 128 eyes of 64 patients were included: 32 amblyopic eyes compared with 32 contralateral eyes and 64 control eyes. Vessel density and perfusion density in the superficial capillary plexus were significantly lower in amblyopic eyes compared to control eyes in 6 × 6 mm (p < 0.02) and 3 × 3 mm (p < 0.01) scans. Correlation analyses showed a linear decrease in vessel density and perfusion density with decreasing visual acuity. The microvascular changes observed were reversible with the occlusion treatment of amblyopia (p < 0.001). CONCLUSIONS: The study found a decrease in vessel density and perfusion density in the macula of children with unilateral functional amblyopia. These microvascular changes were correlated with visual acuity and appeared to be reversible with treatment of amblyopia. On the whole, OCT-A appears to be a relevant complementary examination when it comes to diagnosing and monitoring functional amblyopia.

Intra-ocular lens extrusion in a patient with corneal graft melting.

PURPOSE: Postoperative extrusion of an intraocular lens at a site unrelated to the surgical incision is a very rare complication. We report the case of a posterior chamber intraocular lens extrusion through the cornea eight years after a penetrating keratoplasty in a patient with spontaneous aseptic stromal melting. OBSERVATION: A 77-year-old man was treated for pseudophakic bullous keratopathy with a penetrating keratoplasty complicated by chronic graft rejection and severe glaucoma. He referred to our emergency department eight years after the surgery. The examination showed that the pseudophakic lens optic had eroded completely through the donor cornea. The globe remained intact during the extrusion process. The patient underwent excision of the pre-intraocular lens tissue, removal of intraocular lens implant and capsular bag, liberation of synechia, anterior vitrectomy and corneal graft under general anesthesia. There was no complication during or after the surgery. Histologic study suggests that the intraocular lens optic was covered by conjunctival epithelium with malpighian metaplasia. CONCLUSION: To our knowledge, it's the first case of posterior chamber intraocular extrusion through ocular tissues following penetrating keratoplasty. This case emphasizes the importance of early identification of risk factors, strong postoperative follow up and good patient compliance and the need to minimize drug and surgery-induced iatrogenic effects. If the complication does ensue, early surgical intervention may prevent or minimize serious damage.