Corneal Higher-order Aberrations and Visual Improvement Following Corneal Transplantation in Treating Herpes Simplex Keratitis

Changes in corneal higher-order aberrations during treatment for infectious keratitis

This study aimed to quantify the changes in corneal higher-order aberrations (HOAs) before and after treatment for infectious keratitis and verify the correlation between corneal HOAs and visual acuity. Corneal HOAs were analysed using swept-source anterior segment optical coherence tomography (AS-OCT). Ninety-eight eyes of 96 consecutive patients with infectious keratitis treated with topical eye drops were retrospectively evaluated. Corneal HOAs increased with the infection but decreased with infection resolution following antimicrobial treatment. Corneal HOAs became larger as the degree of corneal findings became more severe. The increase in HOAs of the total cornea was correlated with the decrease in visual acuity both before and after treatment (4 mm, ρ = 0.530 and 0.590; 6 mm, ρ = 0.479 and 0.567, respectively; all P < 0.0001). Furthermore, pretreatment HOA (anterior, 6 mm), pretreatment logMAR best spectacle-corrected visual acuity, and age were prognostic factors significantly associated with posttreatment visual acuity (β = 0.31, P = 0.013; β = 0.36, P < 0.0001; and β = 0.35, P = 0.0007, respectively) (adjusted R² = 0.474). These results indicate that corneal HOAs quantified using AS-OCT can be used as an objective index to evaluate corneal optical function during the treatment of infectious keratitis.

Evidence in the prevention of the recurrence of herpes simplex and herpes zoster keratitis after eye surgery

OBJECTIVE

Herpetic keratitis, either due to herpes simplex keratitis (HSK) or herpes zoster ophthalmicus (HZO), can recur after eye surgery.º Prophylaxis is postulated as necessary to avoid it. The objective of this study was to review the scientific evidence on the preventive methods used in the perioperative period in patients previously affected by HSK/HZO.

METHODS

An exhaustive search was carried out in the PubMed and Web of Science databases to identify relevant articles on prophylaxis and risk of recurrence of HSK/HZO in patients undergoing eye surgery up to 31 December 2019.

RESULTS

There is strong evidence that oral prophylaxis should be recommended after penetrating keratoplasty in patients who have previously had HSK/HZO. For other types of surgery, the evidence is less compelling. However, a latent period of inactivity should be considered between disease and oral prophylaxis.

CONCLUSIONS

Penetrating and lamellar keratoplasty, corneal crosslinking, cataract surgery, and photorefractive and phototherapeutic surgery cause an alteration of the subbasal nerve plexus of the cornea. Due to surgical trauma, as well as the modulation of the ocular immune response caused by steroids applied in the postoperative period, it is possible to induce the reactivation of HSK/HZO, which is common in some cases. Within this article, we discuss the available evidence for HSK/HZO prophylaxis in eye surgery. Further studies are necessary to define the real risk of HSK/HZO recurrence after ocular surgeries, particularly in cataract surgery, and to confirm the efficacy of perioperative prophylaxis with anti-HSK/HZO antivirals.

A Study Validating the Estimation of Anterior Chamber Depth and Iridocorneal Angle with Portable and Non-Portable Slit-Lamp Microscopy

This study assessed the anterior chamber depth (ACD) and iridocorneal angle using a portable smart eye camera (SEC) compared to the conventional slit-lamp microscope and anterior-segment optical coherence tomography (AS-OCT). This retrospective case-control study included 170 eyes from 85 Japanese patients. The correlation between the ACD evaluations conducted with the SEC and conventional slit-lamp was high (r = 0.814). The correlation between the Van-Herick Plus grade obtained using two devices was also high (r = 0.919). A high kappa value was observed for the Van-Herick Plus grading (Kappa = 0.757). A moderate correlation was observed between the ACD measured using AS-OCT and the slit-lamp image acquired with the conventional slit-lamp microscope and SEC (r = 0.609 and 0.641). A strong correlation was observed between the trabecular-iris angle (TIA) measured using AS-OCT and Van-Herick Plus grade obtained with the conventional slit-lamp microscope and SEC (r = 0.702 and 0.764). Strong correlations of ACD evaluation and high kappa value of the Van-Herick Plus grading indicated the adequate subjective assessment function of the SEC. Moderate correlations between the ACD objective measurement and evaluation and strong correlation between the TIA and Van-Herick Plus grade suggested the good objective assessment function of the SEC. The SEC demonstrated adequate performance for ACD evaluation and angle estimation.

Corneal Graft Success Rates in HSV Keratitis: A Systematic Review

Herpes Simplex Virus (HSV) has worldwide prevalence. The primary objective of this systematic review was to compare penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK) regarding the efficacy and complications of the treatment of corneal scarring caused by herpes simplex keratitis. Out of the 469 articles identified during the combined search of the literature based on the PubMed and Cochrane libraries, 10 retrospective and 2 prospective studies published from January 2010 to December 2019 were included. The study outcomes indicated that both surgical approaches resulted in a comparable improvement of visual acuity (VA). However, DALK demonstrated fewer complications in the majority of studies. Higher graft survival rates were associated with higher acyclovir (ACV) doses (above 800 mg/day), topical steroid and antibiotic drops. In conclusion, in terms of postoperative VA, both PK and DALK demonstrate comparable efficacy. However, DALK, which is applied in less severe HSK cases, is associated with fewer complications and better graft survival rates. High dosages of ACV, topical steroids and antibiotics contribute significantly to improved postoperative outcomes.

Ocular surgery after herpes simplex and herpes zoster keratitis

PURPOSE

The recurrence of herpetic stromal keratitis (HSK) and herpes zoster ophthalmicus (HZO) has been reported after a variety of ocular surgeries. The aim of this study was to review the evidence on the preventive methods employed in the perioperative period in patients having undergone HSK/HZO.

METHODS

The PubMed and Web of Science databases were the main resources used to conduct the medical literature search. An extensive search was performed to identify relevant articles concerning the prophylaxis against and risk of HSK/HZO recurrence in patients undergoing ocular surgery up to December 31, 2019.

RESULTS

The disturbance of the corneal nerve plexus occurs during several ocular surgeries including penetrating keratoplasty, lamellar keratoplasty, corneal cross-linking, cataract surgery, as well as photorefractive and phototherapeutic procedures. Such trauma, as well as modulation of the ocular immunological response caused by steroids applied postoperatively, might engender the HSK/HZO reactivation which is not uncommon. There is strong evidence that oral prophylaxis should be recommended just after surgery in patients undergoing penetrating keratoplasty and having suffered from HSK/HZO. For other types of surgeries, the evidence is less compelling; nevertheless, a period of disease quiescence and oral prophylaxis should still be considered.

CONCLUSIONS

Within the article, we discuss the available evidence for HSK/HZO prophylaxis in ocular surgery. Additional studies would be required to define the real risk of HSK/HZO recurrence following eye surgeries, and particularly cataract surgery, and to confirm the utility of perioperative HSK/HZO prophylaxis.

Corneal higher-order aberrations in phlyctenular keratitis

PURPOSE

To characterize tomographic patterns and quantify corneal higher-order aberrations (HOAs) in eyes with corneal scar due to phlyctenular keratitis.

STUDY DESIGN

Retrospective consecutive case series.

METHODS

This study included 51 eyes of 38 patients (24 women; 14 men) with corneal scar due to phlyctenular keratitis. HOAs of the total cornea, and of the anterior and posterior surfaces were measured using anterior segment optical coherence tomography (AS-OCT). Corneal tomographic patterns were classified into five types: increased regular astigmatism, ectasia, asymmetric, flattening and minimal change patterns. The correlation between corneal HOAs and visual acuity was evaluated.

RESULTS

Mean months from onset was 50.7 ± 74.7 and mean number of recurrences 2.1 ± 1.1 (1-5). Mean logarithm of the minimal angle of resolution (logMAR) was 0.19 ± 0.31. AS-OCT showed ectasia pattern in 16 eyes (31.4%), asymmetric pattern in 12 eyes (23.5%), increased regular astigmatism pattern in 9 eyes (17.6%), flattening pattern in 3 eyes (5.9%) and minimal change pattern in 11 eyes (21.6%). HOAs of the total cornea were 0.57 ± 0.44 μm and 1.16 ± 0.77 μm within a 4-mm and 6-mm diameter, significantly larger than in normal controls (P < 0.0001). LogMAR visual acuity was significantly correlated with corneal HOAs (4-mm: r = 0.558, P < 0.0001, 6-mm: r = 0.566, P < 0.0001), central corneal thickness (r = - 0.349, P = 0.016), and corneal astigmatism (r = 0.414, P = 0.004), but not with average keratometric value (r = - 0.092, P = 0.537).

CONCLUSIONS

The most common tomographic pattern was ectasia, followed by a asymmetric pattern in eyes with phlyctenular keratitis. Corneal HOAs were associated with decreased visual acuity in phlyctenular keratitis patients.

Quantitative evaluation of visual function in patients with cornea verticillata associated with Fabry disease

PURPOSE

To evaluate the visual function of patients with cornea verticillata associated with Fabry disease through quantitative evaluations of contrast sensitivity function and straylight.

METHODS

We enrolled 28 eyes of 14 patients with Fabry disease (mean age, 37.1 ± 17.2  years) and 20 eyes of 20 age-matched healthy controls. Comprehensive ophthalmological examinations were performed and contrast sensitivity and letter contrast sensitivity were measured for all patients, following which the area under the log contrast sensitivity function (AULCSF) was calculated. Straylight was quantified using a straylight metre. Furthermore, subgroup analysis was performed according to the whorl-like pattern of cornea verticillata (mild and typical groups).

RESULTS

All 28 eyes showed cornea verticillata. Visual acuity and letter contrast sensitivity values were the same for normal eyes and those with Fabry disease. AULCSF differed by 0.15 log[s] between the eyes with Fabry disease and the control eyes (p < 0.001), while straylight differed by 0.45 log[s] between the two groups (p < 0.001). Subgroup analysis based on the whorl-like pattern of cornea verticillata showed that AULCSF and straylight differed by 0.11 log[s] and 0.08 log[s], respectively, between the typical and mild groups (p = 0.036 and p = 0.147, respectively).

CONCLUSION

Although cornea verticillata associated with Fabry disease does not affect the visual acuity and letter contrast sensitivity, more comprehensive testing of visual function by the inclusion of straylight and grating contrast sensitivity measurements shows clear functional deficits in these patients.

Impact of Corneal Higher-Order Aberrations on Visual Acuity After Deep Anterior Lamellar Keratoplasty in Treating Keratoconus

PURPOSE

To evaluate the incidence of the Descemet membrane (DM) folds after deep anterior lamellar keratoplasty (DALK) in treating keratoconus. We also evaluated the influence of DM folds and corneal higher-order aberrations (HOAs) on visual acuity after DALK.

METHODS

This retrospective study included 89 consecutive eyes of 87 patients who underwent DALK for the treatment of keratoconus at Tokyo Dental College Ichikawa General Hospital from April 2002 to June 2017. The presence or absence of DM folds was determined by slitlamp microscopy. Visual acuity after DALK was compared between the eyes with and without DM folds. Corneal HOAs of the anterior and posterior surfaces and the total cornea were measured by anterior segment optical coherence tomography. Correlations among the presence of DM folds, corneal HOAs, and visual acuity were analyzed.

RESULTS

The Descemet membrane folds developed in 28.1% (25/89) eyes after DALK for the treatment of keratoconus. However, there were no significant differences in postoperative visual acuity between the eyes with and without DM folds at 1, 3, 6, and 12 months (P=0.739, P=0.106, P=0.223, and P=0.186, respectively). The visual acuity at 12 months was significantly correlated with corneal HOAs within a 4-mm diameter (anterior surface: R=0.546, P=0.003; total cornea: R=0.506, P=0.007).

CONCLUSIONS

Larger corneal HOAs, but not the presence of DM folds, were associated with poor visual acuity after DALK. In treating advanced keratoconus with DALK, it is important to minimize postoperative corneal HOAs, although DALK improves visual acuity by reducing HOAs due to keratoconus.