Evaluation of ocular surface following PreserFlo Microshunt implantation: Functional outcomes and quality of life

Gloria Gambini, Matteo Mario Carlà, Federico Giannuzzi, Alfonso Savastano, Tomaso Caporossi, Antonio Baldascino, Danilo Iannetta, Lorenzo Vielmo, Stanislao Rizzo

Research output: Contribution to journalArticle


Background: This study aimed to evaluate the impact of PreserFlo Microshunt on the ocular surface, focusing on both objective and subjective parameters.Methods: Prospective-observational study on 48 eyes undergoing PreserFlo Microshunt implantation, standalone or combined with phacoemulsification. At baseline, 1-month, 6-months and 12-months post-operative follow-ups, we performed Ocular Surface Disease Index (OSDI) questionnaire, Schirmer's test (ST), Tear-film break-up time (TBUT), fluoresceine staining (FS), tear osmolarity and minimum corneal epithelial thickness (Epi-Thk(MIN.) ) measurements.Results: OSDI score improved from 37.43 +/- 17.49 at baseline, to 24.13 +/- 12.55 at 1-month (p = 0.003) and to 12.89 +/- 8.54 and 13.09 +/- 10.22 at 6-months and 12-months (p < 0.0001). TBUT and ST, in a similar way, non-significantly increased at 1-month, but then improved at 6-months and 12-months (p < 0.05 for both). Tear osmolarity significantly decreased from 308.2 +/- 7.3 mOsm/L at baseline, to 303.3 +/- 8.2 mOsm/L, 295.6.2 +/- 7.0 mOsm/L and 297.6 +/- 6.8 mOsm/L at 1-month, 6-months and 12-months (p < 0.05 for all). Epi-Thk(MIN) was stable when comparing baseline (44.9 +/- 5.7 mu m) and 1-month (p = 0.28), and successively increased in 6-months (47.8 +/- 5.5 mu m, p = 0.02) and 12-months (48.0 +/- 3.6 mu m, p = 0.01). In subgroup analysis, OSDI score and tear osmolarity were significantly higher at 1-month in combined group compared to standalone group (p = 0.03 and p = 0.02, respectively), but reaching comparable values in successive follow-ups. Further, Oxford scale grades for FS were significantly improved when comparing baseline-6-months and baseline-12-months.Conclusion: PreserFlo implantation improved ocular surface subjective symptoms, increased TBUT and ST, and reduced FS, highlighting the potential benefits of this surgical intervention. Moreover, we reported significant improvements of tear osmolarity and corneal epithelium.
Original languageEnglish
Pages (from-to)42-53
Number of pages12
JournalClinical and Experimental Ophthalmology
Publication statusPublished - 2024


  • PreserFlo Microshunt
  • corneal epithelium
  • dry eye disease
  • ocular surface
  • tear osmolarity


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