Systemic Associations with Keratoconus.

Keratoconus is a disease of the cornea that results in progressive steepening and thinning of the cornea and subsequent vision loss. It nearly always presents as a bilateral disease, suggesting that there is an underlying abnormality of the corneas that becomes manifest with time. However, the mechanisms underlying the development of keratoconus are largely unknown. Associations reported between keratoconus and systemic diseases are abundant in the literature, and the list of possible associations is very long. We found that atopy, Down syndrome, and various connective tissue diseases were the most frequently cited associations in our broad literature search. Additionally, Diabetes Mellitus has been increasingly studied as a possible protective factor against keratoconus. In this review, we have summarized the evidence for and against these particular systemic conditions and keratoconus and have discussed some of the implications of keratoconus patients having these conditions.

Comparison of surgical techniques for recurrent pterygium.

OBJECTIVE: Although conjunctival autograft (CAU) and amniotic membrane grafting (AMG) with mitomycin-C (MMC) are most effective for the treatment of primary pterygium, the optimal surgical treatment of recurrent pterygium is not well established. We thus aimed to examine recurrence rates after recurrent pterygium excision surgery performed with CAU or AMG with or without MMC. METHODS: We performed a retrospective review of adult patients who underwent recurrent pterygium excision surgery at Boston Medical Center between January 1999 and July 2019. Postoperative recurrence rates were compared between surgical treatment groups: CAU + MMC, CAU, AMG + MMC, and AMG. Postoperative and any intraoperative complications were recorded. RESULTS: We identified 41 eyes of 38 patients having undergone recurrent pterygium excision surgery that met our criteria. The observed postoperative recurrence rates were 0% (0 of 8 eyes) with CAU + MMC, 17.7% (3 of 17 eyes) with CAU, 45.5% (5 of 11 eyes) with AMG + MMC, and 80.0% (4 of 5 eyes) with AMG. The postoperative recurrence rate was significantly lower with CAU than with AMG, both with (p = 0.045) and without (p = 0.021) adjuvant MMC. There were no statistically significant differences in repeat recurrence rates with or without MMC with CAU (p = 0.52) or with AMG (p = 0.31). There was 1 reported case of possible complication from MMC resulting in complete amniotic membrane melt. CONCLUSIONS: Our study suggests that CAU results in less repeat recurrence than AMG in the treatment of recurrent pterygium. The use of intraoperative MMC may decrease the recurrence rate, but it is not statistically significant and may be associated with complications.

Granular corneal dystrophy recurrence at the posterior graft-host interface after type 1 big bubble deep anterior lamellar keratoplasty.

PURPOSE: To describe our observations of granular corneal dystrophy (GCD) recurrence isolated to the posterior graft-host interface after type 1 big bubble (BB) deep anterior lamellar keratoplasty (DALK). OBSERVATIONS: We performed a retrospective chart review of 3 eyes in 2 patients, and literature review to summarize GCD recurrence patterns after DALK. A 29-year-old man with GCD underwent DALK by type 1 BB technique. Three years following surgery, he was found to have recurrence of GCD deposits isolated to the posterior graft-host interface. Similarly, a 53-year-old woman with GCD underwent DALK by BB type 1 technique, and was noted to have trace residual deposits at the posterior graft-host interface that increased in number and size over the course of 6 years. Her fellow eye underwent DALK with type 2 BB formation, without evidence of graft-host interface recurrence over a four year period. Our literature review describes the recurrence patterns of 18 cases of GCD following DALK. CONCLUSIONS AND IMPORTANCE: DALK can be prone to GCD recurrence in the central posterior graft-host interface. Recurrent deposits isolated to the posterior graft-host interface following type 1 BB DALK supports the hypothesis that GCD recurrence may be due to residual pathologic keratocytes in the pre-Descemet layer (PDL).

Detection of Malignancy in Ocular Surface Lesions by Inverse Spectroscopic Optical Coherence Tomography and Two-Photon Autofluorescence.

PURPOSE: Advanced imaging is increasingly important in the diagnosis of ocular surface malignancy. Inverse spectroscopic optical coherence tomography (ISOCT) and two-photon autofluorescence microscopy (2P-AF) are emerging techniques capable of quantifying ultrastructural and metabolic changes, respectively. We aimed to detect malignancy in ocular surface lesions using ISOCT and 2P-AF. METHODS: Portions of excised specimens from patients undergoing conjunctival biopsy at Boston Medical Center were imaged by ISOCT and/or 2P-AF, and submitted for histologic diagnosis. Lesions were categorized as malignant, premalignant (with dysplasia) or benign. ISOCT and 2P-AF findings were compared between categories. RESULTS: Fourteen specimens from 13 patients were collected. The IS-OCT marker D was 2.2-fold higher in combined malignant and premalignant (4.27 ± 0.28, n = 3) versus benign (1.92 ± 0.26, n = 11) lesions (P = 9 × 10-4). ISOCT markers µs and µb were not significantly different. By 2P-AF, the redox ratio was 0.24-fold lower in premalignant (0.11 ± 0.004, n = 2) versus benign (0.45 ± 0.04, n = 9) lesions (P = 1.08 × 10-5). CONCLUSIONS: Conjunctival lesions with higher malignant potential had higher D and lower redox ratios. Higher D can correlate with ultrastructural changes associated with malignancy, similar to what has been seen in cancers of the gut mucosa. Lower redox ratios can suggest the presence of the Warburg effect, which is associated with tumorigenesis. TRANSLATIONAL RELEVANCE: IS-OCT and 2P-AF can potentially be applied to the detection of malignancy or malignant potential in ocular surface lesions. ISOCT allows for the detection of nanoscale ultrastructural changes that are not resolvable by conventional OCT.