Persistence of granular corneal dystrophy type-1 deposits in the predescemetic layer after big-bubble deep anterior lamellar keratoplasty / Persistência de depósitos da distrofia corneal granular tipo-1 na camada pre-Descemet após transplante lamelar anterior profundo

ABSTRACT We report intraoperative finding of Granular Corneal Dystrophy Type-1 (GCD1) deposits after stromal pneumodissection in deep anterior lamellar keratoplasty (DALK) in a 61-year-old female. Pneumodissection was performed from the center to the periphery of the cornea, characterizing a big bubble type 1 technique which dissects the deep stroma from the predescemetic layer. After stromal removal, persistence of whitish deposits inside the predescemetic layer was noted. During post-operative evaluation, anterior biomicroscopy and anterior segment optical coherence tomography showed granular opacities between the patient's Descemet's membrane and the donor cornea, suggesting possible involvement of the predescemetic layer in GCD1. This may require the surgeon's attention to choose between DALK keratoplasty or penetrating keratoplasty.

RESUMO Relatamos o achado intraoperatório de persistência dos depósitos de Distrofia Granular Tipo 1 (GCD1) após pneumodissecção estromal no transplante de córnea lamelar anterior profundo (DALK) em uma mulher de 61 anos. A pneumodissecção começou a partir do centro para a periferia da córnea, caracterizando uma big bubble tipo 1, que disseca o estroma profundo da camada pré-Descemet. Após a remoção do estroma, notamos a persistência de depósitos esbranquiçados no interior da camada pré-Descemet. Na avaliação pós-operatória, a biomicroscopia anterior e a tomografia de coerência óptica do segmento anterior evidenciaram opacidades granulares entre a membrana de Descemet e a córnea doadora, sugerindo o possível envolvimento da camada pré-Descemet na GCD1, o que pode chamar atenção do cirurgião para decidir entre manter o DALK ou converter para transplante penetrante.

Flap analysis: critical point in laser in situ keratomileusis.

A prospective study of 151 eyes, which underwent laser in situ keratomileusis, was done. Corneal flap creation was performed by using Moria LSK- One microkeratome (160 micrometers thickness) (distributed by Microtech, Inc., Moria, France). Flap thickness (measured by high frequency ultrasound), flap diameter (both horizontal and vertical), hinge size and pupillary hinge distance were recorded. The actual values from the measurement were compared to the predicted values from the microkeratome. The mean flap thickness was 161 +/- 38 micrometers compare to 160 micrometers predicted value. The mean diameter of the flap was 9.00 +/- 0.64 mm vertical and 8.94 +/- 0.54 mm horizontal compare to 9.00 mm predicted value. The hinge size was 4.75 +/- 0.84 mm. The pupillary-hinge distance was 3.35 +/- 0.61 mm. There was very high variable of the flap thickness, which can lead to miscalculation of the residual stroma. This miscalculation will be very critical if the residual stroma is left too thin. Caution should be made in higher level of myopia to avoid the serious complication such as keratectasia.