Choroidal vascular analysis in myopic eyes: evidence of foveal medium vessel layer thinning.

PURPOSE: To analyse morphologic features of the choroid in Non-pathological myopic eyes using spectral-domain (SD) optical coherence tomography (OCT). METHODS: Retrospective analysis of enhanced depth SD-OCT images of Non-pathological myopic eyes in comparison with age-matched healthy controls was performed. Choroidal thickness (CT) and large choroidal vessel thickness (LCVT) were measured at the fovea, 750 µm nasally from fovea (N750) and 750 µm temporally (T750) from fovea. Medium choroidal vessel thickness (MCVT) was calculated by subtracting LCVT from CT. Choriocapillaris was encompassed by MCVT, given its reduced thickness. Linear regression analysis evaluated the relationship between age and axial with CT, LCVT and MCVT. RESULTS: The study group comprised 42 eyes of 31 patients (mean age 46.13 ± 15.63; 15 females). Control group included 57 eyes of 34 patients (mean age of 42.3 ± 15.29; 24 females). Mean axial length in myopic eyes and control group was 26.57 ± 1.27 and 23.59 ± 0.99 mm respectively. Myopic eyes showed significant thinning of MCVT and CT at all locations (p < 0.0001) compared to controls, unlike LCVT (p > 0.05). With each decade, thinning of up to 37 µm in CT was noted along with thinning of LCVT (up to 22.6 µm) and MCVT (up to 25 µm). Each mm increase in axial length caused 38.2 µm thinning of choroid along with LCVT (<10 µm), however, MCVT showed more notable thinning (>30 µm). CONCLUSION: Significant thinning of MCVT was noted in non-pathological myopic eyes in comparison to healthy subjects. It appears that MCVT has stronger relationship with age and axial length.

Subfoveal Choroidal Vascularity in Myopia: Evidence From Spectral-Domain Optical Coherence Tomography.

BACKGROUND AND OBJECTIVE: To evaluate subfoveal choroidal vascularity in eyes with myopia in comparison to age-matched healthy subjects. PATIENTS AND METHODS: Retrospective analysis of single foveal enhanced depth imaging optical coherence tomography (EDI-OCT) scans of 30 eyes with myopia (axial length greater than 25 mm). Subfoveal choroidal vascularity was evaluated by calculating vessel-area-to-stromal-area ratio using a previously validated automated algorithm. RESULTS: The subfoveal stromal area was significantly smaller in myopes (0.95 mm3 ± 0.22 mm3) compared to controls (1.33 mm3 ± 0.23 mm3; P < .0001). However, there was no significant difference in vascular area or in vessel-area-to-stroma-area ratio between the groups (P = .15 and P = .16, respectively). Subfoveal choroidal vascularity percentage was also not significantly different between the two groups (P = .07). CONCLUSION: Subfoveal choroidal thinning in myopia is primarily associated with a reduction in choroidal stroma, not vascular components. This needs further exploration and has potential clinical applications. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:202-207.].

Postoperative vitreous hemorrhage after diabetic 23-gauge pars plana vitrectomy.

PURPOSE: To report the frequency of postoperative vitreous hemorrhage (VH) in eyes that underwent primary 23-gauge pars plana vitrectomy (PPV) for nonclearing VH resulting from proliferative diabetic retinopathy, as well as associated risk factors. DESIGN: Retrospective, consecutive, interventional case series. SETTING: Institutional (Retina Service of Wills Eye Institute). STUDY POPULATION: One hundred seventy-three eyes of 157 patients. INTERVENTION: Twenty-three-gauge PPV for nonclearing diabetic VH. MAIN OUTCOME MEASURES: Percentage of eyes in which postoperative VH developed, categorized as early, delayed, or severe persistent, as well as percentage requiring reoperation. RESULTS: During a mean follow-up of 32 weeks, 56 (32%) of 173 eyes demonstrated postoperative VH, categorized as early (8 eyes; 5%), delayed (13 eyes; 8%), or severe persistent (35 eyes; 20%). Twenty-two (13%) of 173 eyes required reoperation: 4 (50%) of 8 in the early group, 8 (62%) of 13 in the delayed group, and 10 (29%) of 35 in the severe persistent group. Mean preoperative logarithm of the minimum angle of resolution visual acuity was 1.5 (Snellen equivalent, approximately 20/600); mean postoperative VA was 0.65 (Snellen equivalent, approximately 20/90), a gain of 0.85 (P < .0001). Thirty-four (27%) of 127 eyes with complete scatter photocoagulation before undergoing PPV compared with 22 (48%) of 46 eyes with incomplete scatter photocoagulation before undergoing PPV demonstrated postoperative VH (P = .002). Other factors associated with postoperative VH included younger age (P = .022) and phakia (P = .036). CONCLUSIONS: Postoperative VH was not uncommon after initial 23-gauge PPV for diabetic VH and was associated with incomplete scatter photocoagulation, younger age, and phakia before PPV. However, only a minority of patients required reoperation.